Support get property context

Co-authored-by: canyie <a1364259@163.com>
Co-authored-by: vvb2060 <vvb2060@gmail.com>
pull/6999/head
topjohnwu 2023-05-18 14:46:32 -07:00
parent fe1ca52f6d
commit f36b21bae5
35 changed files with 42 additions and 3757 deletions

3
.gitmodules vendored
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@ -43,6 +43,9 @@
[submodule "lsplt"]
path = native/src/external/lsplt
url = https://github.com/LSPosed/LSPlt.git
[submodule "system_properties"]
path = native/src/external/system_properties
url = https://github.com/topjohnwu/system_properties.git
[submodule "termux-elf-cleaner"]
path = tools/termux-elf-cleaner
url = https://github.com/termux/termux-elf-cleaner.git

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@ -136,7 +136,6 @@ int magisk_main(int argc, char *argv[]) {
} else if (argc >= 3 && argv[1] == "--install-module"sv) {
install_module(argv[2]);
} else if (argv[1] == "--preinit-device"sv) {
set_log_level_state(LogLevel::Warn, false);
auto name = find_preinit_device();
LOGD("preinit device: %s\n", name.data());
if (!name.empty()) {

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@ -423,6 +423,6 @@ LOCAL_SRC_FILES := \
include $(BUILD_STATIC_LIBRARY)
CWD := $(LOCAL_PATH)
include $(CWD)/systemproperties/Android.mk
include $(CWD)/system_properties/Android.mk
include $(CWD)/mincrypt/Android.mk
include $(CWD)/libcxx/Android.mk

@ -0,0 +1 @@
Subproject commit 7eaf17aa39f1ce156906e36ae3a599054326c307

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@ -1,20 +0,0 @@
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE:= libsystemproperties
LOCAL_C_INCLUDES := $(LOCAL_PATH)/include
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_C_INCLUDES)
LOCAL_STATIC_LIBRARIES := libcxx
LOCAL_CFLAGS := -Wno-deprecated-declarations
LOCAL_SRC_FILES := \
context_node.cpp \
contexts_serialized.cpp \
contexts_split.cpp \
prop_area.cpp \
prop_info.cpp \
system_properties.cpp \
system_property_api.cpp \
system_property_set.cpp \
property_info_parser.cpp
include $(BUILD_STATIC_LIBRARY)

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@ -1,98 +0,0 @@
/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "system_properties/context_node.h"
#include <limits.h>
#include <unistd.h>
#include <async_safe/log.h>
#include "system_properties/system_properties.h"
// pthread_mutex_lock() calls into system_properties in the case of contention.
// This creates a risk of dead lock if any system_properties functions
// use pthread locks after system_property initialization.
//
// For this reason, the below three functions use a bionic Lock and static
// allocation of memory for each filename.
bool ContextNode::Open(bool access_rw, bool* fsetxattr_failed) {
lock_.lock();
if (pa_) {
lock_.unlock();
return true;
}
char filename[PROP_FILENAME_MAX];
int len = async_safe_format_buffer(filename, sizeof(filename), "%s/%s", filename_, context_);
if (len < 0 || len >= PROP_FILENAME_MAX) {
lock_.unlock();
return false;
}
if (access_rw) {
pa_ = prop_area::map_prop_area_rw(filename, context_, fsetxattr_failed);
} else {
pa_ = prop_area::map_prop_area(filename);
}
lock_.unlock();
return pa_;
}
bool ContextNode::CheckAccessAndOpen() {
if (!pa_ && !no_access_) {
if (!CheckAccess() || !Open(false, nullptr)) {
no_access_ = true;
}
}
return pa_;
}
void ContextNode::ResetAccess() {
if (!CheckAccess()) {
Unmap();
no_access_ = true;
} else {
no_access_ = false;
}
}
bool ContextNode::CheckAccess() {
char filename[PROP_FILENAME_MAX];
int len = async_safe_format_buffer(filename, sizeof(filename), "%s/%s", filename_, context_);
if (len < 0 || len >= PROP_FILENAME_MAX) {
return false;
}
return access(filename, R_OK) == 0;
}
void ContextNode::Unmap() {
prop_area::unmap_prop_area(&pa_);
}

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@ -1,172 +0,0 @@
/*
* Copyright (C) 2017 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "system_properties/contexts_serialized.h"
#include <fcntl.h>
#include <limits.h>
#include <sys/mman.h>
#include <sys/prctl.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <new>
#include <async_safe/log.h>
#include "system_properties/system_properties.h"
bool ContextsSerialized::InitializeContextNodes() {
auto num_context_nodes = property_info_area_file_->num_contexts();
auto context_nodes_mmap_size = sizeof(ContextNode) * num_context_nodes;
// We want to avoid malloc in system properties, so we take an anonymous map instead (b/31659220).
void* const map_result = mmap(nullptr, context_nodes_mmap_size, PROT_READ | PROT_WRITE,
MAP_PRIVATE | MAP_ANONYMOUS, -1, 0);
if (map_result == MAP_FAILED) {
return false;
}
prctl(PR_SET_VMA, PR_SET_VMA_ANON_NAME, map_result, context_nodes_mmap_size,
"System property context nodes");
context_nodes_ = reinterpret_cast<ContextNode*>(map_result);
num_context_nodes_ = num_context_nodes;
context_nodes_mmap_size_ = context_nodes_mmap_size;
for (size_t i = 0; i < num_context_nodes; ++i) {
new (&context_nodes_[i]) ContextNode(property_info_area_file_->context(i), filename_);
}
return true;
}
bool ContextsSerialized::MapSerialPropertyArea(bool access_rw, bool* fsetxattr_failed) {
char filename[PROP_FILENAME_MAX];
int len = async_safe_format_buffer(filename, sizeof(filename), "%s/properties_serial", filename_);
if (len < 0 || len >= PROP_FILENAME_MAX) {
serial_prop_area_ = nullptr;
return false;
}
if (access_rw) {
serial_prop_area_ =
prop_area::map_prop_area_rw(filename, "u:object_r:properties_serial:s0", fsetxattr_failed);
} else {
serial_prop_area_ = prop_area::map_prop_area(filename);
}
return serial_prop_area_;
}
bool ContextsSerialized::InitializeProperties() {
if (!property_info_area_file_.LoadDefaultPath()) {
return false;
}
if (!InitializeContextNodes()) {
FreeAndUnmap();
return false;
}
return true;
}
bool ContextsSerialized::Initialize(bool writable, const char* filename, bool* fsetxattr_failed) {
filename_ = filename;
if (!InitializeProperties()) {
return false;
}
if (writable) {
mkdir(filename_, S_IRWXU | S_IXGRP | S_IXOTH);
bool open_failed = false;
if (fsetxattr_failed) {
*fsetxattr_failed = false;
}
for (size_t i = 0; i < num_context_nodes_; ++i) {
if (!context_nodes_[i].Open(true, fsetxattr_failed)) {
open_failed = true;
}
}
if (open_failed || !MapSerialPropertyArea(true, fsetxattr_failed)) {
FreeAndUnmap();
return false;
}
} else {
if (!MapSerialPropertyArea(false, nullptr)) {
FreeAndUnmap();
return false;
}
}
return true;
}
prop_area* ContextsSerialized::GetPropAreaForName(const char* name) {
uint32_t index;
property_info_area_file_->GetPropertyInfoIndexes(name, &index, nullptr);
if (index == ~0u || index >= num_context_nodes_) {
async_safe_format_log(ANDROID_LOG_ERROR, "libc", "Could not find context for property \"%s\"",
name);
return nullptr;
}
auto* context_node = &context_nodes_[index];
if (!context_node->pa()) {
// We explicitly do not check no_access_ in this case because unlike the
// case of foreach(), we want to generate an selinux audit for each
// non-permitted property access in this function.
context_node->Open(false, nullptr);
}
return context_node->pa();
}
void ContextsSerialized::ForEach(void (*propfn)(const prop_info* pi, void* cookie), void* cookie) {
for (size_t i = 0; i < num_context_nodes_; ++i) {
if (context_nodes_[i].CheckAccessAndOpen()) {
context_nodes_[i].pa()->foreach (propfn, cookie);
}
}
}
void ContextsSerialized::ResetAccess() {
for (size_t i = 0; i < num_context_nodes_; ++i) {
context_nodes_[i].ResetAccess();
}
}
void ContextsSerialized::FreeAndUnmap() {
property_info_area_file_.Reset();
if (context_nodes_ != nullptr) {
for (size_t i = 0; i < num_context_nodes_; ++i) {
context_nodes_[i].Unmap();
}
munmap(context_nodes_, context_nodes_mmap_size_);
context_nodes_ = nullptr;
}
prop_area::unmap_prop_area(&serial_prop_area_);
serial_prop_area_ = nullptr;
}

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@ -1,363 +0,0 @@
/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "system_properties/contexts_split.h"
#include <ctype.h>
#include <limits.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <async_safe/log.h>
#include "system_properties/context_node.h"
#include "system_properties/system_properties.h"
class ContextListNode : public ContextNode {
public:
ContextListNode(ContextListNode* next, const char* context, const char* filename)
: ContextNode(strdup(context), filename), next(next) {
}
~ContextListNode() {
free(const_cast<char*>(context()));
}
ContextListNode* next;
};
struct PrefixNode {
PrefixNode(struct PrefixNode* next, const char* prefix, ContextListNode* context)
: prefix(strdup(prefix)), prefix_len(strlen(prefix)), context(context), next(next) {
}
~PrefixNode() {
free(prefix);
}
char* prefix;
const size_t prefix_len;
ContextListNode* context;
PrefixNode* next;
};
template <typename List, typename... Args>
static inline void ListAdd(List** list, Args... args) {
*list = new List(*list, args...);
}
static void ListAddAfterLen(PrefixNode** list, const char* prefix, ContextListNode* context) {
size_t prefix_len = strlen(prefix);
auto next_list = list;
while (*next_list) {
if ((*next_list)->prefix_len < prefix_len || (*next_list)->prefix[0] == '*') {
ListAdd(next_list, prefix, context);
return;
}
next_list = &(*next_list)->next;
}
ListAdd(next_list, prefix, context);
}
template <typename List, typename Func>
static void ListForEach(List* list, Func func) {
while (list) {
func(list);
list = list->next;
}
}
template <typename List, typename Func>
static List* ListFind(List* list, Func func) {
while (list) {
if (func(list)) {
return list;
}
list = list->next;
}
return nullptr;
}
template <typename List>
static void ListFree(List** list) {
while (*list) {
auto old_list = *list;
*list = old_list->next;
delete old_list;
}
}
// The below two functions are duplicated from label_support.c in libselinux.
// TODO: Find a location suitable for these functions such that both libc and
// libselinux can share a common source file.
// The read_spec_entries and read_spec_entry functions may be used to
// replace sscanf to read entries from spec files. The file and
// property services now use these.
// Read an entry from a spec file (e.g. file_contexts)
static inline int read_spec_entry(char** entry, char** ptr, int* len) {
*entry = nullptr;
char* tmp_buf = nullptr;
while (isspace(**ptr) && **ptr != '\0') (*ptr)++;
tmp_buf = *ptr;
*len = 0;
while (!isspace(**ptr) && **ptr != '\0') {
(*ptr)++;
(*len)++;
}
if (*len) {
*entry = strndup(tmp_buf, *len);
if (!*entry) return -1;
}
return 0;
}
// line_buf - Buffer containing the spec entries .
// num_args - The number of spec parameter entries to process.
// ... - A 'char **spec_entry' for each parameter.
// returns - The number of items processed.
//
// This function calls read_spec_entry() to do the actual string processing.
static int read_spec_entries(char* line_buf, int num_args, ...) {
char **spec_entry, *buf_p;
int len, rc, items, entry_len = 0;
va_list ap;
len = strlen(line_buf);
if (line_buf[len - 1] == '\n')
line_buf[len - 1] = '\0';
else
// Handle case if line not \n terminated by bumping
// the len for the check below (as the line is NUL
// terminated by getline(3))
len++;
buf_p = line_buf;
while (isspace(*buf_p)) buf_p++;
// Skip comment lines and empty lines.
if (*buf_p == '#' || *buf_p == '\0') return 0;
// Process the spec file entries
va_start(ap, num_args);
items = 0;
while (items < num_args) {
spec_entry = va_arg(ap, char**);
if (len - 1 == buf_p - line_buf) {
va_end(ap);
return items;
}
rc = read_spec_entry(spec_entry, &buf_p, &entry_len);
if (rc < 0) {
va_end(ap);
return rc;
}
if (entry_len) items++;
}
va_end(ap);
return items;
}
bool ContextsSplit::MapSerialPropertyArea(bool access_rw, bool* fsetxattr_failed) {
char filename[PROP_FILENAME_MAX];
int len = async_safe_format_buffer(filename, sizeof(filename), "%s/properties_serial", filename_);
if (len < 0 || len >= PROP_FILENAME_MAX) {
serial_prop_area_ = nullptr;
return false;
}
if (access_rw) {
serial_prop_area_ =
prop_area::map_prop_area_rw(filename, "u:object_r:properties_serial:s0", fsetxattr_failed);
} else {
serial_prop_area_ = prop_area::map_prop_area(filename);
}
return serial_prop_area_;
}
bool ContextsSplit::InitializePropertiesFromFile(const char* filename) {
FILE* file = fopen(filename, "re");
if (!file) {
return false;
}
char* buffer = nullptr;
size_t line_len;
char* prop_prefix = nullptr;
char* context = nullptr;
while (getline(&buffer, &line_len, file) > 0) {
int items = read_spec_entries(buffer, 2, &prop_prefix, &context);
if (items <= 0) {
continue;
}
if (items == 1) {
free(prop_prefix);
continue;
}
// init uses ctl.* properties as an IPC mechanism and does not write them
// to a property file, therefore we do not need to create property files
// to store them.
if (!strncmp(prop_prefix, "ctl.", 4)) {
free(prop_prefix);
free(context);
continue;
}
auto old_context = ListFind(
contexts_, [context](ContextListNode* l) { return !strcmp(l->context(), context); });
if (old_context) {
ListAddAfterLen(&prefixes_, prop_prefix, old_context);
} else {
ListAdd(&contexts_, context, filename_);
ListAddAfterLen(&prefixes_, prop_prefix, contexts_);
}
free(prop_prefix);
free(context);
}
free(buffer);
fclose(file);
return true;
}
bool ContextsSplit::InitializeProperties() {
// If we do find /property_contexts, then this is being
// run as part of the OTA updater on older release that had
// /property_contexts - b/34370523
if (InitializePropertiesFromFile("/property_contexts")) {
return true;
}
// Use property_contexts from /system & /vendor, fall back to those from /
if (access("/system/etc/selinux/plat_property_contexts", R_OK) != -1) {
if (!InitializePropertiesFromFile("/system/etc/selinux/plat_property_contexts")) {
return false;
}
// Don't check for failure here, so we always have a sane list of properties.
// E.g. In case of recovery, the vendor partition will not have mounted and we
// still need the system / platform properties to function.
if (access("/vendor/etc/selinux/vendor_property_contexts", R_OK) != -1) {
InitializePropertiesFromFile("/vendor/etc/selinux/vendor_property_contexts");
} else {
// Fallback to nonplat_* if vendor_* doesn't exist.
InitializePropertiesFromFile("/vendor/etc/selinux/nonplat_property_contexts");
}
} else {
if (!InitializePropertiesFromFile("/plat_property_contexts")) {
return false;
}
if (access("/vendor_property_contexts", R_OK) != -1) {
InitializePropertiesFromFile("/vendor_property_contexts");
} else {
// Fallback to nonplat_* if vendor_* doesn't exist.
InitializePropertiesFromFile("/nonplat_property_contexts");
}
}
return true;
}
bool ContextsSplit::Initialize(bool writable, const char* filename, bool* fsetxattr_failed) {
filename_ = filename;
if (!InitializeProperties()) {
return false;
}
if (writable) {
mkdir(filename_, S_IRWXU | S_IXGRP | S_IXOTH);
bool open_failed = false;
if (fsetxattr_failed) {
*fsetxattr_failed = false;
}
ListForEach(contexts_, [&fsetxattr_failed, &open_failed](ContextListNode* l) {
if (!l->Open(true, fsetxattr_failed)) {
open_failed = true;
}
});
if (open_failed || !MapSerialPropertyArea(true, fsetxattr_failed)) {
FreeAndUnmap();
return false;
}
} else {
if (!MapSerialPropertyArea(false, nullptr)) {
FreeAndUnmap();
return false;
}
}
return true;
}
prop_area* ContextsSplit::GetPropAreaForName(const char* name) {
auto entry = ListFind(prefixes_, [name](PrefixNode* l) {
return l->prefix[0] == '*' || !strncmp(l->prefix, name, l->prefix_len);
});
if (!entry) {
return nullptr;
}
auto cnode = entry->context;
if (!cnode->pa()) {
// We explicitly do not check no_access_ in this case because unlike the
// case of foreach(), we want to generate an selinux audit for each
// non-permitted property access in this function.
cnode->Open(false, nullptr);
}
return cnode->pa();
}
void ContextsSplit::ForEach(void (*propfn)(const prop_info* pi, void* cookie), void* cookie) {
ListForEach(contexts_, [propfn, cookie](ContextListNode* l) {
if (l->CheckAccessAndOpen()) {
l->pa()->foreach (propfn, cookie);
}
});
}
void ContextsSplit::ResetAccess() {
ListForEach(contexts_, [](ContextListNode* l) { l->ResetAccess(); });
}
void ContextsSplit::FreeAndUnmap() {
ListFree(&prefixes_);
ListFree(&contexts_);
prop_area::unmap_prop_area(&serial_prop_area_);
}

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@ -1,144 +0,0 @@
/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _INCLUDE_SYS__SYSTEM_PROPERTIES_H
#define _INCLUDE_SYS__SYSTEM_PROPERTIES_H
#include <sys/cdefs.h>
#include <stdint.h>
#ifndef _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
#error you should #include <sys/system_properties.h> instead
#endif
//#include <sys/system_properties.h>
#include "system_properties.h"
__BEGIN_DECLS
#define PROP_SERVICE_NAME "property_service"
#define PROP_FILENAME "/dev/__properties__"
#define PROP_MSG_SETPROP 1
#define PROP_MSG_SETPROP2 0x00020001
#define PROP_SUCCESS 0
#define PROP_ERROR_READ_CMD 0x0004
#define PROP_ERROR_READ_DATA 0x0008
#define PROP_ERROR_READ_ONLY_PROPERTY 0x000B
#define PROP_ERROR_INVALID_NAME 0x0010
#define PROP_ERROR_INVALID_VALUE 0x0014
#define PROP_ERROR_PERMISSION_DENIED 0x0018
#define PROP_ERROR_INVALID_CMD 0x001B
#define PROP_ERROR_HANDLE_CONTROL_MESSAGE 0x0020
#define PROP_ERROR_SET_FAILED 0x0024
/*
** This was previously for testing, but now that SystemProperties is its own testable class,
** there is never a reason to call this function and its implementation simply returns -1.
*/
int __system_property_set_filename(const char* __filename);
/*
** Initialize the area to be used to store properties. Can
** only be done by a single process that has write access to
** the property area.
*/
int __system_property_area_init(void);
/* Read the global serial number of the system properties
**
** Called to predict if a series of cached __system_property_find
** objects will have seen __system_property_serial values change.
** But also aids the converse, as changes in the global serial can
** also be used to predict if a failed __system_property_find
** could in-turn now find a new object; thus preventing the
** cycles of effort to poll __system_property_find.
**
** Typically called at beginning of a cache cycle to signal if _any_ possible
** changes have occurred since last. If there is, one may check each individual
** __system_property_serial to confirm dirty, or __system_property_find
** to check if the property now exists. If a call to __system_property_add
** or __system_property_update has completed between two calls to
** __system_property_area_serial then the second call will return a larger
** value than the first call. Beware of race conditions as changes to the
** properties are not atomic, the main value of this call is to determine
** whether the expensive __system_property_find is worth retrying to see if
** a property now exists.
**
** Returns the serial number on success, -1 on error.
*/
uint32_t __system_property_area_serial(void);
/* Add a new system property. Can only be done by a single
** process that has write access to the property area, and
** that process must handle sequencing to ensure the property
** does not already exist and that only one property is added
** or updated at a time.
**
** Returns 0 on success, -1 if the property area is full.
*/
int __system_property_add(const char* __name, unsigned int __name_length, const char* __value, unsigned int __value_length);
/* Delete a system property. Added in resetprop
**
** Returns 0 on success, -1 if the property area is full.
*/
int __system_property_delete(const char *__name, bool __trim_node);
/* Update the value of a system property returned by
** __system_property_find. Can only be done by a single process
** that has write access to the property area, and that process
** must handle sequencing to ensure that only one property is
** updated at a time.
**
** Returns 0 on success, -1 if the parameters are incorrect.
*/
int __system_property_update(prop_info* __pi, const char* __value, unsigned int __value_length);
/* Read the serial number of a system property returned by
** __system_property_find.
**
** Returns the serial number on success, -1 on error.
*/
uint32_t __system_property_serial(const prop_info* __pi);
/* Initialize the system properties area in read only mode.
* Should be done by all processes that need to read system
* properties.
*
* Returns 0 on success, -1 otherwise.
*/
int __system_properties_init(void);
/* Deprecated: use __system_property_wait instead. */
uint32_t __system_property_wait_any(uint32_t __old_serial);
__END_DECLS
#endif

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#pragma once
#define async_safe_format_buffer snprintf
#define async_safe_format_log(...) /* NOP */

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/*
* Copyright (C) 2013 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <errno.h>
#include "bionic_macros.h"
class ErrnoRestorer {
public:
explicit ErrnoRestorer() : saved_errno_(errno) {
}
~ErrnoRestorer() {
errno = saved_errno_;
}
void override(int new_errno) {
saved_errno_ = new_errno;
}
private:
int saved_errno_;
BIONIC_DISALLOW_COPY_AND_ASSIGN(ErrnoRestorer);
};

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/*
* Copyright (C) 2017 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef __BIONIC_PRIVATE_BIONIC_DEFS_H_
#define __BIONIC_PRIVATE_BIONIC_DEFS_H_
/*
* This label is used to mark libc/libdl symbols that may need to be replaced
* by native bridge implementation.
*/
#define __BIONIC_WEAK_FOR_NATIVE_BRIDGE __attribute__((__weak__, __noinline__))
#define __BIONIC_WEAK_VARIABLE_FOR_NATIVE_BRIDGE __attribute__((__weak__))
#endif /* __BIONIC_PRIVATE_BIONIC_DEFS_H_ */

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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _BIONIC_FUTEX_H
#define _BIONIC_FUTEX_H
#include <errno.h>
#include <linux/futex.h>
#include <stdbool.h>
#include <stddef.h>
#include <sys/cdefs.h>
#include <sys/syscall.h>
#include <unistd.h>
struct timespec;
static inline __always_inline int __futex(volatile void* ftx, int op, int value,
const timespec* timeout, int bitset) {
// Our generated syscall assembler sets errno, but our callers (pthread functions) don't want to.
int saved_errno = errno;
int result = syscall(__NR_futex, ftx, op, value, timeout, NULL, bitset);
if (__predict_false(result == -1)) {
result = -errno;
errno = saved_errno;
}
return result;
}
static inline int __futex_wake(volatile void* ftx, int count) {
return __futex(ftx, FUTEX_WAKE, count, nullptr, 0);
}
static inline int __futex_wake_ex(volatile void* ftx, bool shared, int count) {
return __futex(ftx, shared ? FUTEX_WAKE : FUTEX_WAKE_PRIVATE, count, nullptr, 0);
}
static inline int __futex_wait(volatile void* ftx, int value, const timespec* timeout) {
return __futex(ftx, FUTEX_WAIT, value, timeout, 0);
}
static inline int __futex_wait_ex(volatile void* ftx, bool shared, int value) {
return __futex(ftx, (shared ? FUTEX_WAIT_BITSET : FUTEX_WAIT_BITSET_PRIVATE), value, nullptr,
FUTEX_BITSET_MATCH_ANY);
}
__LIBC_HIDDEN__ int __futex_wait_ex(volatile void* ftx, bool shared, int value,
bool use_realtime_clock, const timespec* abs_timeout);
static inline int __futex_pi_unlock(volatile void* ftx, bool shared) {
return __futex(ftx, shared ? FUTEX_UNLOCK_PI : FUTEX_UNLOCK_PI_PRIVATE, 0, nullptr, 0);
}
__LIBC_HIDDEN__ int __futex_pi_lock_ex(volatile void* ftx, bool shared, bool use_realtime_clock,
const timespec* abs_timeout);
#endif /* _BIONIC_FUTEX_H */

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/*
* Copyright (C) 2015 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#pragma once
#include <stdatomic.h>
#include "private/bionic_futex.h"
#include "private/bionic_macros.h"
// Lock is used in places like pthread_rwlock_t, which can be initialized without calling
// an initialization function. So make sure Lock can be initialized by setting its memory to 0.
class Lock {
private:
enum LockState {
Unlocked = 0,
LockedWithoutWaiter,
LockedWithWaiter,
};
_Atomic(LockState) state;
bool process_shared;
public:
void init(bool process_shared) {
atomic_init(&state, Unlocked);
this->process_shared = process_shared;
}
bool trylock() {
LockState old_state = Unlocked;
return __predict_true(atomic_compare_exchange_strong_explicit(&state, &old_state,
LockedWithoutWaiter, memory_order_acquire, memory_order_relaxed));
}
void lock() {
LockState old_state = Unlocked;
if (__predict_true(atomic_compare_exchange_strong_explicit(&state, &old_state,
LockedWithoutWaiter, memory_order_acquire, memory_order_relaxed))) {
return;
}
while (atomic_exchange_explicit(&state, LockedWithWaiter, memory_order_acquire) != Unlocked) {
// TODO: As the critical section is brief, it is a better choice to spin a few times befor sleeping.
__futex_wait_ex(&state, process_shared, LockedWithWaiter);
}
return;
}
void unlock() {
bool shared = process_shared; /* cache to local variable */
if (atomic_exchange_explicit(&state, Unlocked, memory_order_release) == LockedWithWaiter) {
__futex_wake_ex(&state, shared, 1);
}
}
};
class LockGuard {
public:
explicit LockGuard(Lock& lock) : lock_(lock) {
lock_.lock();
}
~LockGuard() {
lock_.unlock();
}
BIONIC_DISALLOW_COPY_AND_ASSIGN(LockGuard);
private:
Lock& lock_;
};

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/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#pragma once
#include <stdint.h>
#define BIONIC_DISALLOW_COPY_AND_ASSIGN(TypeName) \
TypeName(const TypeName&) = delete; \
void operator=(const TypeName&) = delete
#define BIONIC_DISALLOW_IMPLICIT_CONSTRUCTORS(TypeName) \
TypeName() = delete; \
BIONIC_DISALLOW_COPY_AND_ASSIGN(TypeName)
#define BIONIC_ROUND_UP_POWER_OF_2(value) \
((sizeof(value) == 8) \
? (1UL << (64 - __builtin_clzl(static_cast<unsigned long>(value)))) \
: (1UL << (32 - __builtin_clz(static_cast<unsigned int>(value)))))
static constexpr uintptr_t align_down(uintptr_t p, size_t align) {
return p & ~(align - 1);
}
static constexpr uintptr_t align_up(uintptr_t p, size_t align) {
return (p + align - 1) & ~(align - 1);
}
template <typename T>
static inline T* align_down(T* p, size_t align) {
return reinterpret_cast<T*>(align_down(reinterpret_cast<uintptr_t>(p), align));
}
template <typename T>
static inline T* align_up(T* p, size_t align) {
return reinterpret_cast<T*>(align_up(reinterpret_cast<uintptr_t>(p), align));
}
#if defined(__arm__)
// Do not emit anything for arm, clang does not allow emiting an arm unwind
// directive.
// #define BIONIC_STOP_UNWIND asm volatile(".cantunwind")
#define BIONIC_STOP_UNWIND
#elif defined(__aarch64__)
#define BIONIC_STOP_UNWIND asm volatile(".cfi_undefined x30")
#elif defined(__i386__)
#define BIONIC_STOP_UNWIND asm volatile(".cfi_undefined \%eip")
#elif defined(__x86_64__)
#define BIONIC_STOP_UNWIND asm volatile(".cfi_undefined \%rip")
#elif defined (__mips__)
#define BIONIC_STOP_UNWIND asm volatile(".cfi_undefined $ra")
#endif
// The arraysize(arr) macro returns the # of elements in an array arr.
// The expression is a compile-time constant, and therefore can be
// used in defining new arrays, for example. If you use arraysize on
// a pointer by mistake, you will get a compile-time error.
//
// One caveat is that arraysize() doesn't accept any array of an
// anonymous type or a type defined inside a function.
//
// This template function declaration is used in defining arraysize.
// Note that the function doesn't need an implementation, as we only
// use its type.
template <typename T, size_t N>
char (&ArraySizeHelper(T (&array)[N]))[N]; // NOLINT(readability/casting)
#define arraysize(array) (sizeof(ArraySizeHelper(array)))
// Used to inform clang's -Wimplicit-fallthrough that a fallthrough is intended. There's no way to
// silence (or enable, apparently) -Wimplicit-fallthrough in C yet.
#ifdef __cplusplus
#define __BIONIC_FALLTHROUGH [[clang::fallthrough]]
#else
#define __BIONIC_FALLTHROUGH
#endif

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#pragma once
#include <stdio.h>
#include <syscall.h>
// Missing defines
#ifndef PR_SET_VMA
#define PR_SET_VMA 0x53564d41
#endif
#ifndef PR_SET_VMA_ANON_NAME
#define PR_SET_VMA_ANON_NAME 0
#endif
// Rename symbols
#pragma redefine_extname __system_property_set _system_property_set2
#pragma redefine_extname __system_property_find _system_property_find2
#pragma redefine_extname __system_property_read_callback _system_property_read_callback2
#pragma redefine_extname __system_property_foreach __system_property_foreach2
#pragma redefine_extname __system_property_wait __system_property_wait2
#pragma redefine_extname __system_property_read __system_property_read2
#pragma redefine_extname __system_property_get __system_property_get2
#pragma redefine_extname __system_property_find_nth __system_property_find_nth2
#pragma redefine_extname __system_property_set_filename __system_property_set_filename2
#pragma redefine_extname __system_property_area_init __system_property_area_init2
#pragma redefine_extname __system_property_area_serial __system_property_area_serial2
#pragma redefine_extname __system_property_add __system_property_add2
#pragma redefine_extname __system_property_update __system_property_update2
#pragma redefine_extname __system_property_serial __system_property_serial2
#pragma redefine_extname __system_properties_init __system_properties_init2
#pragma redefine_extname __system_property_wait_any __system_property_wait_any2

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//
// Copyright (C) 2017 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#ifndef PROPERTY_INFO_PARSER_H
#define PROPERTY_INFO_PARSER_H
#include <stdint.h>
#include <stdlib.h>
namespace android {
namespace properties {
// The below structs intentionally do not end with char name[0] or other tricks to allocate
// with a dynamic size, such that they can be added onto in the future without breaking
// backwards compatibility.
struct PropertyEntry {
uint32_t name_offset;
uint32_t namelen;
// This is the context match for this node_; ~0u if it doesn't correspond to any.
uint32_t context_index;
// This is the type for this node_; ~0u if it doesn't correspond to any.
uint32_t type_index;
};
struct TrieNodeInternal {
// This points to a property entry struct, which includes the name for this node
uint32_t property_entry;
// Children are a sorted list of child nodes_; binary search them.
uint32_t num_child_nodes;
uint32_t child_nodes;
// Prefixes are terminating prefix matches at this node, sorted longest to smallest
// Take the first match sequentially found with StartsWith().
uint32_t num_prefixes;
uint32_t prefix_entries;
// Exact matches are a sorted list of exact matches at this node_; binary search them.
uint32_t num_exact_matches;
uint32_t exact_match_entries;
};
struct PropertyInfoAreaHeader {
// The current version of this data as created by property service.
uint32_t current_version;
// The lowest version of libc that can properly parse this data.
uint32_t minimum_supported_version;
uint32_t size;
uint32_t contexts_offset;
uint32_t types_offset;
uint32_t root_offset;
};
class SerializedData {
public:
uint32_t size() const {
return reinterpret_cast<const PropertyInfoAreaHeader*>(data_base_)->size;
}
const char* c_string(uint32_t offset) const {
if (offset != 0 && offset > size()) return nullptr;
return static_cast<const char*>(data_base_ + offset);
}
const uint32_t* uint32_array(uint32_t offset) const {
if (offset != 0 && offset > size()) return nullptr;
return reinterpret_cast<const uint32_t*>(data_base_ + offset);
}
uint32_t uint32(uint32_t offset) const {
if (offset != 0 && offset > size()) return ~0u;
return *reinterpret_cast<const uint32_t*>(data_base_ + offset);
}
const char* data_base() const { return data_base_; }
private:
const char data_base_[0];
};
class TrieNode {
public:
TrieNode() : serialized_data_(nullptr), trie_node_base_(nullptr) {}
TrieNode(const SerializedData* data_base, const TrieNodeInternal* trie_node_base)
: serialized_data_(data_base), trie_node_base_(trie_node_base) {}
const char* name() const {
return serialized_data_->c_string(node_property_entry()->name_offset);
}
uint32_t context_index() const { return node_property_entry()->context_index; }
uint32_t type_index() const { return node_property_entry()->type_index; }
uint32_t num_child_nodes() const { return trie_node_base_->num_child_nodes; }
TrieNode child_node(int n) const {
uint32_t child_node_offset = serialized_data_->uint32_array(trie_node_base_->child_nodes)[n];
const TrieNodeInternal* trie_node_base =
reinterpret_cast<const TrieNodeInternal*>(serialized_data_->data_base() + child_node_offset);
return TrieNode(serialized_data_, trie_node_base);
}
bool FindChildForString(const char* input, uint32_t namelen, TrieNode* child) const;
uint32_t num_prefixes() const { return trie_node_base_->num_prefixes; }
const PropertyEntry* prefix(int n) const {
uint32_t prefix_entry_offset =
serialized_data_->uint32_array(trie_node_base_->prefix_entries)[n];
return reinterpret_cast<const PropertyEntry*>(serialized_data_->data_base() +
prefix_entry_offset);
}
uint32_t num_exact_matches() const { return trie_node_base_->num_exact_matches; }
const PropertyEntry* exact_match(int n) const {
uint32_t exact_match_entry_offset =
serialized_data_->uint32_array(trie_node_base_->exact_match_entries)[n];
return reinterpret_cast<const PropertyEntry*>(serialized_data_->data_base() +
exact_match_entry_offset);
}
private:
const PropertyEntry* node_property_entry() const {
return reinterpret_cast<const PropertyEntry*>(serialized_data_->data_base() +
trie_node_base_->property_entry);
}
const SerializedData* serialized_data_;
const TrieNodeInternal* trie_node_base_;
};
class PropertyInfoArea : private SerializedData {
public:
void GetPropertyInfoIndexes(const char* name, uint32_t* context_index, uint32_t* type_index) const;
void GetPropertyInfo(const char* property, const char** context, const char** type) const;
int FindContextIndex(const char* context) const;
int FindTypeIndex(const char* type) const;
const char* context(uint32_t index) const {
uint32_t context_array_size_offset = contexts_offset();
const uint32_t* context_array = uint32_array(context_array_size_offset + sizeof(uint32_t));
return data_base() + context_array[index];
}
const char* type(uint32_t index) const {
uint32_t type_array_size_offset = types_offset();
const uint32_t* type_array = uint32_array(type_array_size_offset + sizeof(uint32_t));
return data_base() + type_array[index];
}
uint32_t current_version() const { return header()->current_version; }
uint32_t minimum_supported_version() const { return header()->minimum_supported_version; }
uint32_t size() const { return SerializedData::size(); }
uint32_t num_contexts() const { return uint32_array(contexts_offset())[0]; }
uint32_t num_types() const { return uint32_array(types_offset())[0]; }
TrieNode root_node() const { return trie(header()->root_offset); }
private:
void CheckPrefixMatch(const char* remaining_name, const TrieNode& trie_node,
uint32_t* context_index, uint32_t* type_index) const;
const PropertyInfoAreaHeader* header() const {
return reinterpret_cast<const PropertyInfoAreaHeader*>(data_base());
}
uint32_t contexts_offset() const { return header()->contexts_offset; }
uint32_t contexts_array_offset() const { return contexts_offset() + sizeof(uint32_t); }
uint32_t types_offset() const { return header()->types_offset; }
uint32_t types_array_offset() const { return types_offset() + sizeof(uint32_t); }
TrieNode trie(uint32_t offset) const {
if (offset != 0 && offset > size()) return TrieNode();
const TrieNodeInternal* trie_node_base =
reinterpret_cast<const TrieNodeInternal*>(data_base() + offset);
return TrieNode(this, trie_node_base);
}
};
// This is essentially a smart pointer for read only mmap region for property contexts.
class PropertyInfoAreaFile {
public:
PropertyInfoAreaFile() : mmap_base_(nullptr), mmap_size_(0) {}
~PropertyInfoAreaFile() { Reset(); }
PropertyInfoAreaFile(const PropertyInfoAreaFile&) = delete;
void operator=(const PropertyInfoAreaFile&) = delete;
PropertyInfoAreaFile(PropertyInfoAreaFile&&) = default;
PropertyInfoAreaFile& operator=(PropertyInfoAreaFile&&) = default;
bool LoadDefaultPath();
bool LoadPath(const char* filename);
const PropertyInfoArea* operator->() const {
return reinterpret_cast<const PropertyInfoArea*>(mmap_base_);
}
explicit operator bool() const { return mmap_base_ != nullptr; }
void Reset();
private:
void* mmap_base_;
size_t mmap_size_;
};
} // namespace properties
} // namespace android
#endif

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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#ifndef _INCLUDE_SYS_SYSTEM_PROPERTIES_H
#define _INCLUDE_SYS_SYSTEM_PROPERTIES_H
#include <sys/cdefs.h>
#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>
#include "private/hacks.h"
__BEGIN_DECLS
typedef struct prop_info prop_info;
#define PROP_VALUE_MAX 92
/*
* Sets system property `name` to `value`, creating the system property if it doesn't already exist.
*/
int __system_property_set(const char* __name, const char* __value) __INTRODUCED_IN(12);
/*
* Returns a `prop_info` corresponding system property `name`, or nullptr if it doesn't exist.
* Use __system_property_read_callback to query the current value.
*
* Property lookup is expensive, so it can be useful to cache the result of this function.
*/
const prop_info* __system_property_find(const char* __name);
/*
* Calls `callback` with a consistent trio of name, value, and serial number for property `pi`.
*/
void __system_property_read_callback(const prop_info* __pi,
void (*__callback)(void* __cookie, const char* __name, const char* __value, uint32_t __serial),
void* __cookie) __INTRODUCED_IN(26);
/*
* Passes a `prop_info` for each system property to the provided
* callback. Use __system_property_read_callback() to read the value.
*
* This method is for inspecting and debugging the property system, and not generally useful.
*/
int __system_property_foreach(void (*__callback)(const prop_info* __pi, void* __cookie), void* __cookie)
__INTRODUCED_IN(19);
/*
* Waits for the specific system property identified by `pi` to be updated
* past `old_serial`. Waits no longer than `relative_timeout`, or forever
* if `relaive_timeout` is null.
*
* If `pi` is null, waits for the global serial number instead.
*
* If you don't know the current serial, use 0.
*
* Returns true and updates `*new_serial_ptr` on success, or false if the call
* timed out.
*/
struct timespec;
bool __system_property_wait(const prop_info* __pi, uint32_t __old_serial, uint32_t* __new_serial_ptr, const struct timespec* __relative_timeout)
__INTRODUCED_IN(26);
/* Deprecated. In Android O and above, there's no limit on property name length. */
#define PROP_NAME_MAX 32
/* Deprecated. Use __system_property_read_callback instead. */
int __system_property_read(const prop_info* __pi, char* __name, char* __value);
/* Deprecated. Use __system_property_read_callback instead. */
int __system_property_get(const char* __name, char* __value);
/* Deprecated. Use __system_property_foreach instead. */
const prop_info* __system_property_find_nth(unsigned __n);
__END_DECLS
#endif

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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#pragma once
#include "private/bionic_lock.h"
#include "prop_area.h"
class ContextNode {
public:
ContextNode(const char* context, const char* filename)
: context_(context), pa_(nullptr), no_access_(false), filename_(filename) {
lock_.init(false);
}
~ContextNode() {
Unmap();
}
BIONIC_DISALLOW_COPY_AND_ASSIGN(ContextNode);
bool Open(bool access_rw, bool* fsetxattr_failed);
bool CheckAccessAndOpen();
void ResetAccess();
void Unmap();
const char* context() const {
return context_;
}
prop_area* pa() {
return pa_;
}
private:
bool CheckAccess();
Lock lock_;
const char* context_;
prop_area* pa_;
bool no_access_;
const char* filename_;
};

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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#pragma once
#include "prop_area.h"
#include "prop_info.h"
class Contexts {
public:
virtual ~Contexts() {
}
virtual bool Initialize(bool writable, const char* filename, bool* fsetxattr_failed) = 0;
virtual prop_area* GetPropAreaForName(const char* name) = 0;
virtual prop_area* GetSerialPropArea() = 0;
virtual void ForEach(void (*propfn)(const prop_info* pi, void* cookie), void* cookie) = 0;
virtual void ResetAccess() = 0;
virtual void FreeAndUnmap() = 0;
};

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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#pragma once
#include "contexts.h"
#include "prop_area.h"
#include "prop_info.h"
class ContextsPreSplit : public Contexts {
public:
virtual ~ContextsPreSplit() override {
}
// We'll never initialize this legacy option as writable, so don't even check the arg.
virtual bool Initialize(bool, const char* filename, bool*) override {
pre_split_prop_area_ = prop_area::map_prop_area(filename);
return pre_split_prop_area_ != nullptr;
}
virtual prop_area* GetPropAreaForName(const char*) override {
return pre_split_prop_area_;
}
virtual prop_area* GetSerialPropArea() override {
return pre_split_prop_area_;
}
virtual void ForEach(void (*propfn)(const prop_info* pi, void* cookie), void* cookie) override {
pre_split_prop_area_->foreach (propfn, cookie);
}
// This is a no-op for pre-split properties as there is only one property file and it is
// accessible by all domains
virtual void ResetAccess() override {
}
virtual void FreeAndUnmap() override {
prop_area::unmap_prop_area(&pre_split_prop_area_);
}
private:
prop_area* pre_split_prop_area_ = nullptr;
};

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/*
* Copyright (C) 2017 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#pragma once
#include <property_info_parser/property_info_parser.h>
#include "context_node.h"
#include "contexts.h"
class ContextsSerialized : public Contexts {
public:
virtual ~ContextsSerialized() override {
}
virtual bool Initialize(bool writable, const char* filename, bool* fsetxattr_failed) override;
virtual prop_area* GetPropAreaForName(const char* name) override;
virtual prop_area* GetSerialPropArea() override {
return serial_prop_area_;
}
virtual void ForEach(void (*propfn)(const prop_info* pi, void* cookie), void* cookie) override;
virtual void ResetAccess() override;
virtual void FreeAndUnmap() override;
private:
bool InitializeContextNodes();
bool InitializeProperties();
bool MapSerialPropertyArea(bool access_rw, bool* fsetxattr_failed);
const char* filename_;
android::properties::PropertyInfoAreaFile property_info_area_file_;
ContextNode* context_nodes_ = nullptr;
size_t num_context_nodes_ = 0;
size_t context_nodes_mmap_size_ = 0;
prop_area* serial_prop_area_ = nullptr;
};

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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#pragma once
#include "contexts.h"
struct PrefixNode;
class ContextListNode;
class ContextsSplit : public Contexts {
public:
virtual ~ContextsSplit() override {
}
virtual bool Initialize(bool writable, const char* filename, bool* fsetxattr_failed) override;
virtual prop_area* GetPropAreaForName(const char* name) override;
virtual prop_area* GetSerialPropArea() override {
return serial_prop_area_;
}
virtual void ForEach(void (*propfn)(const prop_info* pi, void* cookie), void* cookie) override;
virtual void ResetAccess() override;
virtual void FreeAndUnmap() override;
private:
bool MapSerialPropertyArea(bool access_rw, bool* fsetxattr_failed);
bool InitializePropertiesFromFile(const char* filename);
bool InitializeProperties();
PrefixNode* prefixes_ = nullptr;
ContextListNode* contexts_ = nullptr;
prop_area* serial_prop_area_ = nullptr;
const char* filename_ = nullptr;
};

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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#pragma once
#include <stdatomic.h>
#include <stdint.h>
#include <string.h>
#include <sys/mman.h>
#include "private/bionic_macros.h"
#include "prop_info.h"
// Properties are stored in a hybrid trie/binary tree structure.
// Each property's name is delimited at '.' characters, and the tokens are put
// into a trie structure. Siblings at each level of the trie are stored in a
// binary tree. For instance, "ro.secure"="1" could be stored as follows:
//
// +-----+ children +----+ children +--------+
// | |-------------->| ro |-------------->| secure |
// +-----+ +----+ +--------+
// / \ / |
// left / \ right left / | prop +===========+
// v v v +-------->| ro.secure |
// +-----+ +-----+ +-----+ +-----------+
// | net | | sys | | com | | 1 |
// +-----+ +-----+ +-----+ +===========+
// Represents a node in the trie.
struct prop_bt {
uint32_t namelen;
// The property trie is updated only by the init process (single threaded) which provides
// property service. And it can be read by multiple threads at the same time.
// As the property trie is not protected by locks, we use atomic_uint_least32_t types for the
// left, right, children "pointers" in the trie node. To make sure readers who see the
// change of "pointers" can also notice the change of prop_bt structure contents pointed by
// the "pointers", we always use release-consume ordering pair when accessing these "pointers".
// prop "points" to prop_info structure if there is a propery associated with the trie node.
// Its situation is similar to the left, right, children "pointers". So we use
// atomic_uint_least32_t and release-consume ordering to protect it as well.
// We should also avoid rereading these fields redundantly, since not
// all processor implementations ensure that multiple loads from the
// same field are carried out in the right order.
atomic_uint_least32_t prop;
atomic_uint_least32_t left;
atomic_uint_least32_t right;
atomic_uint_least32_t children;
char name[0];
prop_bt(const char* name, const uint32_t name_length) {
this->namelen = name_length;
memcpy(this->name, name, name_length);
this->name[name_length] = '\0';
}
private:
BIONIC_DISALLOW_COPY_AND_ASSIGN(prop_bt);
};
class prop_area {
public:
static prop_area* map_prop_area_rw(const char* filename, const char* context,
bool* fsetxattr_failed);
static prop_area* map_prop_area(const char* filename);
static void unmap_prop_area(prop_area** pa) {
if (*pa) {
munmap(*pa, pa_size_);
*pa = nullptr;
}
}
prop_area(const uint32_t magic, const uint32_t version) : magic_(magic), version_(version) {
atomic_init(&serial_, 0u);
memset(reserved_, 0, sizeof(reserved_));
// Allocate enough space for the root node.
bytes_used_ = sizeof(prop_bt);
}
const prop_info* find(const char* name);
bool add(const char* name, unsigned int namelen, const char* value, unsigned int valuelen);
bool rm(const char *name, bool trim_node);
bool foreach (void (*propfn)(const prop_info* pi, void* cookie), void* cookie);
atomic_uint_least32_t* serial() {
return &serial_;
}
uint32_t magic() const {
return magic_;
}
uint32_t version() const {
return version_;
}
private:
static prop_area* map_fd_ro(const int fd);
void* allocate_obj(const size_t size, uint_least32_t* const off);
prop_bt* new_prop_bt(const char* name, uint32_t namelen, uint_least32_t* const off);
prop_info* new_prop_info(const char* name, uint32_t namelen, const char* value, uint32_t valuelen,
uint_least32_t* const off);
void* to_prop_obj(uint_least32_t off);
prop_bt* to_prop_bt(atomic_uint_least32_t* off_p);
prop_info* to_prop_info(atomic_uint_least32_t* off_p);
prop_bt* root_node();
/* resetprop new: traverse through the trie and find the node */
prop_bt *find_prop_bt(prop_bt *const bt, const char* name, bool alloc_if_needed);
/* resetprop new: trim unneeded nodes from trie */
bool prune_node(prop_bt *const node);
prop_bt* find_prop_bt(prop_bt* const bt, const char* name, uint32_t namelen, bool alloc_if_needed);
const prop_info* find_property(prop_bt* const trie, const char* name, uint32_t namelen,
const char* value, uint32_t valuelen, bool alloc_if_needed);
bool foreach_property(prop_bt* const trie, void (*propfn)(const prop_info* pi, void* cookie),
void* cookie);
// The original design doesn't include pa_size or pa_data_size in the prop_area struct itself.
// Since we'll need to be backwards compatible with that design, we don't gain much by adding it
// now, especially since we don't have any plans to make different property areas different sizes,
// and thus we share these two variables among all instances.
static size_t pa_size_;
static size_t pa_data_size_;
uint32_t bytes_used_;
atomic_uint_least32_t serial_;
uint32_t magic_;
uint32_t version_;
uint32_t reserved_[28];
char data_[0];
BIONIC_DISALLOW_COPY_AND_ASSIGN(prop_area);
};

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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#pragma once
#include <stdatomic.h>
#include <stdint.h>
//#include <sys/system_properties.h>
#include "../system_properties.h"
#include "private/bionic_macros.h"
// The C11 standard doesn't allow atomic loads from const fields,
// though C++11 does. Fudge it until standards get straightened out.
static inline uint_least32_t load_const_atomic(const atomic_uint_least32_t* s, memory_order mo) {
atomic_uint_least32_t* non_const_s = const_cast<atomic_uint_least32_t*>(s);
return atomic_load_explicit(non_const_s, mo);
}
struct prop_info {
// Read only properties will not set anything but the bottom most bit of serial and the top byte.
// We borrow the 2nd from the top byte for extra flags, and use the bottom most bit of that for
// our first user, kLongFlag.
constexpr static uint32_t kLongFlag = 1 << 16;
// The error message fits in part of a union with the previous 92 char property value so there
// must be room left over after the error message for the offset to the new longer property value
// and future expansion fields if needed. Note that this value cannot ever increase. The offset
// to the new longer property value appears immediately after it, so an increase of this size will
// break compatibility.
constexpr static size_t kLongLegacyErrorBufferSize = 56;
public:
atomic_uint_least32_t serial;
// we need to keep this buffer around because the property
// value can be modified whereas name is constant.
union {
char value[PROP_VALUE_MAX];
struct {
char error_message[kLongLegacyErrorBufferSize];
uint32_t offset;
} long_property;
};
char name[0];
bool is_long() const {
return (load_const_atomic(&serial, memory_order_relaxed) & kLongFlag) != 0;
}
const char* long_value() const {
// We can't store pointers here since this is shared memory that will have different absolute
// pointers in different processes. We don't have data_ from prop_area, but since we know
// `this` is data_ + some offset and long_value is data_ + some other offset, we calculate the
// offset from `this` to long_value and store it as long_property.offset.
return reinterpret_cast<const char*>(this) + long_property.offset;
}
prop_info(const char* name, uint32_t namelen, const char* value, uint32_t valuelen);
prop_info(const char* name, uint32_t namelen, uint32_t long_offset);
private:
BIONIC_DISALLOW_IMPLICIT_CONSTRUCTORS(prop_info);
};
static_assert(sizeof(prop_info) == 96, "sizeof struct prop_info must be 96 bytes");

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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#pragma once
#include <stdint.h>
#include <sys/param.h>
//#include <sys/system_properties.h>
#include "../system_properties.h"
#include "contexts.h"
#include "contexts_pre_split.h"
#include "contexts_serialized.h"
#include "contexts_split.h"
constexpr int PROP_FILENAME_MAX = 1024;
class SystemProperties {
public:
friend struct LocalPropertyTestState;
friend class SystemPropertiesTest;
// Note that system properties are initialized before libc calls static initializers, so
// doing any initialization in this constructor is an error. Even a Constructor that zero
// initializes this class will clobber the previous property initialization.
// We rely on the static SystemProperties in libc to be placed in .bss and zero initialized.
SystemProperties() = default;
// Special constructor for testing that also zero initializes the important members.
explicit SystemProperties(bool initialized) : initialized_(initialized) {
}
BIONIC_DISALLOW_COPY_AND_ASSIGN(SystemProperties);
bool Init(const char* filename);
bool AreaInit(const char* filename, bool* fsetxattr_failed);
uint32_t AreaSerial();
const prop_info* Find(const char* name);
int Read(const prop_info* pi, char* name, char* value);
void ReadCallback(const prop_info* pi,
void (*callback)(void* cookie, const char* name, const char* value,
uint32_t serial),
void* cookie);
int Get(const char* name, char* value);
int Update(prop_info* pi, const char* value, unsigned int len);
int Add(const char* name, unsigned int namelen, const char* value, unsigned int valuelen);
int Delete(const char *name, bool trim_node);
uint32_t Serial(const prop_info* pi);
uint32_t WaitAny(uint32_t old_serial);
bool Wait(const prop_info* pi, uint32_t old_serial, uint32_t* new_serial_ptr,
const timespec* relative_timeout);
const prop_info* FindNth(unsigned n);
int Foreach(void (*propfn)(const prop_info* pi, void* cookie), void* cookie);
private:
// We don't want to use new or malloc in properties (b/31659220), and we don't want to waste a
// full page by using mmap(), so we set aside enough space to create any context of the three
// contexts.
static constexpr size_t kMaxContextsAlign =
MAX(alignof(ContextsSerialized), MAX(alignof(ContextsSplit), alignof(ContextsPreSplit)));
static constexpr size_t kMaxContextsSize =
MAX(sizeof(ContextsSerialized), MAX(sizeof(ContextsSplit), sizeof(ContextsPreSplit)));
alignas(kMaxContextsAlign) char contexts_data_[kMaxContextsSize];
Contexts* contexts_;
bool initialized_;
char property_filename_[PROP_FILENAME_MAX];
};

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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "system_properties/prop_area.h"
#include <errno.h>
#include <fcntl.h>
#include <stdlib.h>
#include <sys/cdefs.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <sys/xattr.h>
#include <unistd.h>
#include <new>
#include <async_safe/log.h>
constexpr size_t PA_SIZE = 128 * 1024;
constexpr uint32_t PROP_AREA_MAGIC = 0x504f5250;
constexpr uint32_t PROP_AREA_VERSION = 0xfc6ed0ab;
size_t prop_area::pa_size_ = 0;
size_t prop_area::pa_data_size_ = 0;
prop_area* prop_area::map_prop_area_rw(const char* filename, const char* context,
bool* fsetxattr_failed) {
/* dev is a tmpfs that we can use to carve a shared workspace
* out of, so let's do that...
*/
const int fd = open(filename, O_RDWR | O_CREAT | O_NOFOLLOW | O_CLOEXEC | O_EXCL, 0444);
if (fd < 0) {
if (errno == EACCES) {
/* for consistency with the case where the process has already
* mapped the page in and segfaults when trying to write to it
*/
abort();
}
return nullptr;
}
if (context) {
if (fsetxattr(fd, XATTR_NAME_SELINUX, context, strlen(context) + 1, 0) != 0) {
async_safe_format_log(ANDROID_LOG_ERROR, "libc",
"fsetxattr failed to set context (%s) for \"%s\"", context, filename);
/*
* fsetxattr() will fail during system properties tests due to selinux policy.
* We do not want to create a custom policy for the tester, so we will continue in
* this function but set a flag that an error has occurred.
* Init, which is the only daemon that should ever call this function will abort
* when this error occurs.
* Otherwise, the tester will ignore it and continue, albeit without any selinux
* property separation.
*/
if (fsetxattr_failed) {
*fsetxattr_failed = true;
}
}
}
if (ftruncate(fd, PA_SIZE) < 0) {
close(fd);
return nullptr;
}
pa_size_ = PA_SIZE;
pa_data_size_ = pa_size_ - sizeof(prop_area);
void* const memory_area = mmap(nullptr, pa_size_, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (memory_area == MAP_FAILED) {
close(fd);
return nullptr;
}
prop_area* pa = new (memory_area) prop_area(PROP_AREA_MAGIC, PROP_AREA_VERSION);
close(fd);
return pa;
}
prop_area* prop_area::map_fd_ro(const int fd) {
struct stat fd_stat;
if (fstat(fd, &fd_stat) < 0) {
return nullptr;
}
if ((fd_stat.st_uid != 0) || (fd_stat.st_gid != 0) ||
((fd_stat.st_mode & (S_IWGRP | S_IWOTH)) != 0) ||
(fd_stat.st_size < static_cast<off_t>(sizeof(prop_area)))) {
return nullptr;
}
pa_size_ = fd_stat.st_size;
pa_data_size_ = pa_size_ - sizeof(prop_area);
/* resetprop: add PROT_WRITE */
void* const map_result = mmap(nullptr, pa_size_, PROT_READ | PROT_WRITE, MAP_SHARED, fd, 0);
if (map_result == MAP_FAILED) {
return nullptr;
}
prop_area* pa = reinterpret_cast<prop_area*>(map_result);
if ((pa->magic() != PROP_AREA_MAGIC) || (pa->version() != PROP_AREA_VERSION)) {
munmap(pa, pa_size_);
return nullptr;
}
return pa;
}
prop_area* prop_area::map_prop_area(const char* filename) {
/* resetprop: O_RDONLY -> O_RDWR */
int fd = open(filename, O_CLOEXEC | O_NOFOLLOW | O_RDWR);
if (fd == -1) return nullptr;
prop_area* map_result = map_fd_ro(fd);
close(fd);
return map_result;
}
void* prop_area::allocate_obj(const size_t size, uint_least32_t* const off) {
const size_t aligned = __BIONIC_ALIGN(size, sizeof(uint_least32_t));
if (bytes_used_ + aligned > pa_data_size_) {
return nullptr;
}
*off = bytes_used_;
bytes_used_ += aligned;
return data_ + *off;
}
prop_bt* prop_area::new_prop_bt(const char* name, uint32_t namelen, uint_least32_t* const off) {
uint_least32_t new_offset;
void* const p = allocate_obj(sizeof(prop_bt) + namelen + 1, &new_offset);
if (p != nullptr) {
prop_bt* bt = new (p) prop_bt(name, namelen);
*off = new_offset;
return bt;
}
return nullptr;
}
prop_info* prop_area::new_prop_info(const char* name, uint32_t namelen, const char* value,
uint32_t valuelen, uint_least32_t* const off) {
uint_least32_t new_offset;
void* const p = allocate_obj(sizeof(prop_info) + namelen + 1, &new_offset);
if (p == nullptr) return nullptr;
prop_info* info;
if (valuelen >= PROP_VALUE_MAX) {
uint32_t long_value_offset = 0;
char* long_location = reinterpret_cast<char*>(allocate_obj(valuelen + 1, &long_value_offset));
if (!long_location) return nullptr;
memcpy(long_location, value, valuelen);
long_location[valuelen] = '\0';
// Both new_offset and long_value_offset are offsets based off of data_, however prop_info
// does not know what data_ is, so we change this offset to be an offset from the prop_info
// pointer that contains it.
long_value_offset -= new_offset;
info = new (p) prop_info(name, namelen, long_value_offset);
} else {
info = new (p) prop_info(name, namelen, value, valuelen);
}
*off = new_offset;
return info;
}
void* prop_area::to_prop_obj(uint_least32_t off) {
if (off > pa_data_size_) return nullptr;
return (data_ + off);
}
inline prop_bt* prop_area::to_prop_bt(atomic_uint_least32_t* off_p) {
uint_least32_t off = atomic_load_explicit(off_p, memory_order_consume);
return reinterpret_cast<prop_bt*>(to_prop_obj(off));
}
inline prop_info* prop_area::to_prop_info(atomic_uint_least32_t* off_p) {
uint_least32_t off = atomic_load_explicit(off_p, memory_order_consume);
return reinterpret_cast<prop_info*>(to_prop_obj(off));
}
inline prop_bt* prop_area::root_node() {
return reinterpret_cast<prop_bt*>(to_prop_obj(0));
}
static int cmp_prop_name(const char* one, uint32_t one_len, const char* two, uint32_t two_len) {
if (one_len < two_len)
return -1;
else if (one_len > two_len)
return 1;
else
return strncmp(one, two, one_len);
}
prop_bt* prop_area::find_prop_bt(prop_bt* const bt, const char* name, uint32_t namelen,
bool alloc_if_needed) {
prop_bt* current = bt;
while (true) {
if (!current) {
return nullptr;
}
const int ret = cmp_prop_name(name, namelen, current->name, current->namelen);
if (ret == 0) {
return current;
}
if (ret < 0) {
uint_least32_t left_offset = atomic_load_explicit(&current->left, memory_order_relaxed);
if (left_offset != 0) {
current = to_prop_bt(&current->left);
} else {
if (!alloc_if_needed) {
return nullptr;
}
uint_least32_t new_offset;
prop_bt* new_bt = new_prop_bt(name, namelen, &new_offset);
if (new_bt) {
atomic_store_explicit(&current->left, new_offset, memory_order_release);
}
return new_bt;
}
} else {
uint_least32_t right_offset = atomic_load_explicit(&current->right, memory_order_relaxed);
if (right_offset != 0) {
current = to_prop_bt(&current->right);
} else {
if (!alloc_if_needed) {
return nullptr;
}
uint_least32_t new_offset;
prop_bt* new_bt = new_prop_bt(name, namelen, &new_offset);
if (new_bt) {
atomic_store_explicit(&current->right, new_offset, memory_order_release);
}
return new_bt;
}
}
}
}
/* resetprop new: traverse through the trie and find the node.
* This was originally part of prop_area::find_property. */
prop_bt *prop_area::find_prop_bt(prop_bt *const bt, const char *name, bool alloc_if_needed) {
if (!bt) return nullptr;
const char* remaining_name = name;
prop_bt* current = bt;
while (true) {
const char* sep = strchr(remaining_name, '.');
const bool want_subtree = (sep != nullptr);
const uint32_t substr_size = (want_subtree) ? sep - remaining_name : strlen(remaining_name);
if (!substr_size) {
return nullptr;
}
prop_bt* root = nullptr;
uint_least32_t children_offset = atomic_load_explicit(&current->children, memory_order_relaxed);
if (children_offset != 0) {
root = to_prop_bt(&current->children);
} else if (alloc_if_needed) {
uint_least32_t new_offset;
root = new_prop_bt(remaining_name, substr_size, &new_offset);
if (root) {
atomic_store_explicit(&current->children, new_offset, memory_order_release);
}
}
if (!root) {
return nullptr;
}
current = find_prop_bt(root, remaining_name, substr_size, alloc_if_needed);
if (!current) {
return nullptr;
}
if (!want_subtree) break;
remaining_name = sep + 1;
}
return current;
}
/* resetprop: move trie traversal logic out of the function */
const prop_info* prop_area::find_property(prop_bt* const trie, const char* name, uint32_t namelen,
const char* value, uint32_t valuelen,
bool alloc_if_needed) {
prop_bt* current = find_prop_bt(trie, name, alloc_if_needed);
if (!current)
return nullptr;
uint_least32_t prop_offset = atomic_load_explicit(&current->prop, memory_order_relaxed);
if (prop_offset != 0) {
return to_prop_info(&current->prop);
} else if (alloc_if_needed) {
uint_least32_t new_offset;
prop_info* new_info = new_prop_info(name, namelen, value, valuelen, &new_offset);
if (new_info) {
atomic_store_explicit(&current->prop, new_offset, memory_order_release);
}
return new_info;
} else {
return nullptr;
}
}
bool prop_area::foreach_property(prop_bt* const trie,
void (*propfn)(const prop_info* pi, void* cookie), void* cookie) {
if (!trie) return false;
uint_least32_t left_offset = atomic_load_explicit(&trie->left, memory_order_relaxed);
if (left_offset != 0) {
const int err = foreach_property(to_prop_bt(&trie->left), propfn, cookie);
if (err < 0) return false;
}
uint_least32_t prop_offset = atomic_load_explicit(&trie->prop, memory_order_relaxed);
if (prop_offset != 0) {
prop_info* info = to_prop_info(&trie->prop);
if (!info) return false;
propfn(info, cookie);
}
uint_least32_t children_offset = atomic_load_explicit(&trie->children, memory_order_relaxed);
if (children_offset != 0) {
const int err = foreach_property(to_prop_bt(&trie->children), propfn, cookie);
if (err < 0) return false;
}
uint_least32_t right_offset = atomic_load_explicit(&trie->right, memory_order_relaxed);
if (right_offset != 0) {
const int err = foreach_property(to_prop_bt(&trie->right), propfn, cookie);
if (err < 0) return false;
}
return true;
}
const prop_info* prop_area::find(const char* name) {
return find_property(root_node(), name, strlen(name), nullptr, 0, false);
}
bool prop_area::add(const char* name, unsigned int namelen, const char* value,
unsigned int valuelen) {
return find_property(root_node(), name, namelen, value, valuelen, true);
}
bool prop_area::prune_node(prop_bt * const node) {
bool is_leaf = true;
if (atomic_load_explicit(&node->children, memory_order_relaxed) != 0) {
if (prune_node(to_prop_bt(&node->children))) {
atomic_store_explicit(&node->children, 0u, memory_order_release);
} else {
is_leaf = false;
}
}
if (atomic_load_explicit(&node->left, memory_order_relaxed) != 0) {
if (prune_node(to_prop_bt(&node->left))) {
atomic_store_explicit(&node->left, 0u, memory_order_release);
} else {
is_leaf = false;
}
}
if (atomic_load_explicit(&node->right, memory_order_relaxed) != 0) {
if (prune_node(to_prop_bt(&node->right))) {
atomic_store_explicit(&node->right, 0u, memory_order_release);
} else {
is_leaf = false;
}
}
if (is_leaf && atomic_load_explicit(&node->prop, memory_order_relaxed) == 0) {
// Wipe out this node
memset(node->name, 0, node->namelen);
memset(node, 0, sizeof(*node));
return true;
}
return false;
}
bool prop_area::rm(const char *name, bool trim_node) {
prop_bt *node = find_prop_bt(root_node(), name, false);
if (!node)
return false;
prop_info *info = nullptr;
uint_least32_t prop_offset = atomic_load_explicit(&node->prop, memory_order_relaxed);
if (prop_offset != 0) {
info = to_prop_info(&node->prop);
}
// De-reference the existing property ASAP
atomic_store_explicit(&node->prop, 0u, memory_order_release);
if (info) {
// Wipe out the old info
if (info->is_long()) {
char *value = const_cast<char*>(info->long_value());
memset(value, 0, strlen(value));
}
memset(info->name, 0, strlen(info->name));
memset(info, 0, sizeof(*info));
}
if (trim_node) {
prune_node(root_node());
}
return true;
}
bool prop_area::foreach (void (*propfn)(const prop_info* pi, void* cookie), void* cookie) {
return foreach_property(root_node(), propfn, cookie);
}

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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "system_properties/prop_info.h"
#include <string.h>
constexpr static const char kLongLegacyError[] =
"Must use __system_property_read_callback() to read";
static_assert(sizeof(kLongLegacyError) < prop_info::kLongLegacyErrorBufferSize,
"Error message for long properties read by legacy libc must fit within 56 chars");
prop_info::prop_info(const char* name, uint32_t namelen, const char* value, uint32_t valuelen) {
memcpy(this->name, name, namelen);
this->name[namelen] = '\0';
atomic_init(&this->serial, valuelen << 24);
memcpy(this->value, value, valuelen);
this->value[valuelen] = '\0';
}
prop_info::prop_info(const char* name, uint32_t namelen, uint32_t long_offset) {
memcpy(this->name, name, namelen);
this->name[namelen] = '\0';
atomic_uint_least32_t error_value_len = sizeof(kLongLegacyError) - 1;
atomic_init(&this->serial, error_value_len << 24 | kLongFlag);
memcpy(this->long_property.error_message, kLongLegacyError, sizeof(kLongLegacyError));
this->long_property.offset = long_offset;
}

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@ -1,246 +0,0 @@
//
// Copyright (C) 2017 The Android Open Source Project
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//
#include "property_info_parser/property_info_parser.h"
#include <fcntl.h>
#include <string.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
namespace android {
namespace properties {
namespace {
// Binary search to find index of element in an array compared via f(search).
template <typename F>
int Find(uint32_t array_length, F&& f) {
int bottom = 0;
int top = array_length - 1;
while (top >= bottom) {
int search = (top + bottom) / 2;
auto cmp = f(search);
if (cmp == 0) return search;
if (cmp < 0) bottom = search + 1;
if (cmp > 0) top = search - 1;
}
return -1;
}
} // namespace
// Binary search the list of contexts to find the index of a given context string.
// Only should be used for TrieSerializer to construct the Trie.
int PropertyInfoArea::FindContextIndex(const char* context) const {
return Find(num_contexts(), [this, context](auto array_offset) {
auto string_offset = uint32_array(contexts_array_offset())[array_offset];
return strcmp(c_string(string_offset), context);
});
}
// Binary search the list of types to find the index of a given type string.
// Only should be used for TrieSerializer to construct the Trie.
int PropertyInfoArea::FindTypeIndex(const char* type) const {
return Find(num_types(), [this, type](auto array_offset) {
auto string_offset = uint32_array(types_array_offset())[array_offset];
return strcmp(c_string(string_offset), type);
});
}
// Binary search the list of children nodes to find a TrieNode for a given property piece.
// Used to traverse the Trie in GetPropertyInfoIndexes().
bool TrieNode::FindChildForString(const char* name, uint32_t namelen, TrieNode* child) const {
auto node_index = Find(trie_node_base_->num_child_nodes, [this, name, namelen](auto array_offset) {
const char* child_name = child_node(array_offset).name();
int cmp = strncmp(child_name, name, namelen);
if (cmp == 0 && child_name[namelen] != '\0') {
// We use strncmp() since name isn't null terminated, but we don't want to match only a
// prefix of a child node's name, so we check here if we did only match a prefix and
// return 1, to indicate to the binary search to search earlier in the array for the real
// match.
return 1;
}
return cmp;
});
if (node_index == -1) {
return false;
}
*child = child_node(node_index);
return true;
}
void PropertyInfoArea::CheckPrefixMatch(const char* remaining_name, const TrieNode& trie_node,
uint32_t* context_index, uint32_t* type_index) const {
const uint32_t remaining_name_size = strlen(remaining_name);
for (uint32_t i = 0; i < trie_node.num_prefixes(); ++i) {
auto prefix_len = trie_node.prefix(i)->namelen;
if (prefix_len > remaining_name_size) continue;
if (!strncmp(c_string(trie_node.prefix(i)->name_offset), remaining_name, prefix_len)) {
if (trie_node.prefix(i)->context_index != ~0u) {
*context_index = trie_node.prefix(i)->context_index;
}
if (trie_node.prefix(i)->type_index != ~0u) {
*type_index = trie_node.prefix(i)->type_index;
}
return;
}
}
}
void PropertyInfoArea::GetPropertyInfoIndexes(const char* name, uint32_t* context_index,
uint32_t* type_index) const {
uint32_t return_context_index = ~0u;
uint32_t return_type_index = ~0u;
const char* remaining_name = name;
auto trie_node = root_node();
while (true) {
const char* sep = strchr(remaining_name, '.');
// Apply prefix match for prefix deliminated with '.'
if (trie_node.context_index() != ~0u) {
return_context_index = trie_node.context_index();
}
if (trie_node.type_index() != ~0u) {
return_type_index = trie_node.type_index();
}
// Check prefixes at this node. This comes after the node check since these prefixes are by
// definition longer than the node itself.
CheckPrefixMatch(remaining_name, trie_node, &return_context_index, &return_type_index);
if (sep == nullptr) {
break;
}
const uint32_t substr_size = sep - remaining_name;
TrieNode child_node;
if (!trie_node.FindChildForString(remaining_name, substr_size, &child_node)) {
break;
}
trie_node = child_node;
remaining_name = sep + 1;
}
// We've made it to a leaf node, so check contents and return appropriately.
// Check exact matches
for (uint32_t i = 0; i < trie_node.num_exact_matches(); ++i) {
if (!strcmp(c_string(trie_node.exact_match(i)->name_offset), remaining_name)) {
if (context_index != nullptr) {
if (trie_node.exact_match(i)->context_index != ~0u) {
*context_index = trie_node.exact_match(i)->context_index;
} else {
*context_index = return_context_index;
}
}
if (type_index != nullptr) {
if (trie_node.exact_match(i)->type_index != ~0u) {
*type_index = trie_node.exact_match(i)->type_index;
} else {
*type_index = return_type_index;
}
}
return;
}
}
// Check prefix matches for prefixes not deliminated with '.'
CheckPrefixMatch(remaining_name, trie_node, &return_context_index, &return_type_index);
// Return previously found prefix match.
if (context_index != nullptr) *context_index = return_context_index;
if (type_index != nullptr) *type_index = return_type_index;
return;
}
void PropertyInfoArea::GetPropertyInfo(const char* property, const char** context,
const char** type) const {
uint32_t context_index;
uint32_t type_index;
GetPropertyInfoIndexes(property, &context_index, &type_index);
if (context != nullptr) {
if (context_index == ~0u) {
*context = nullptr;
} else {
*context = this->context(context_index);
}
}
if (type != nullptr) {
if (type_index == ~0u) {
*type = nullptr;
} else {
*type = this->type(type_index);
}
}
}
bool PropertyInfoAreaFile::LoadDefaultPath() {
return LoadPath("/dev/__properties__/property_info");
}
bool PropertyInfoAreaFile::LoadPath(const char* filename) {
int fd = open(filename, O_CLOEXEC | O_NOFOLLOW | O_RDONLY);
struct stat fd_stat;
if (fstat(fd, &fd_stat) < 0) {
close(fd);
return false;
}
if ((fd_stat.st_uid != 0) || (fd_stat.st_gid != 0) ||
((fd_stat.st_mode & (S_IWGRP | S_IWOTH)) != 0) ||
(fd_stat.st_size < static_cast<off_t>(sizeof(PropertyInfoArea)))) {
close(fd);
return false;
}
auto mmap_size = fd_stat.st_size;
void* map_result = mmap(nullptr, mmap_size, PROT_READ, MAP_SHARED, fd, 0);
if (map_result == MAP_FAILED) {
close(fd);
return false;
}
auto property_info_area = reinterpret_cast<PropertyInfoArea*>(map_result);
if (property_info_area->minimum_supported_version() > 1 ||
property_info_area->size() != mmap_size) {
munmap(map_result, mmap_size);
close(fd);
return false;
}
close(fd);
mmap_base_ = map_result;
mmap_size_ = mmap_size;
return true;
}
void PropertyInfoAreaFile::Reset() {
if (mmap_size_ > 0) {
munmap(mmap_base_, mmap_size_);
}
mmap_base_ = nullptr;
mmap_size_ = 0;
}
} // namespace properties
} // namespace android

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/*
* Copyright (C) 2008 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include "system_properties/system_properties.h"
#include <errno.h>
#include <stdatomic.h>
#include <stdlib.h>
#include <string.h>
#include <sys/stat.h>
#include <sys/types.h>
#include <unistd.h>
#include <new>
#include <async_safe/log.h>
#include "private/ErrnoRestorer.h"
#include "private/bionic_futex.h"
#include "system_properties/context_node.h"
#include "system_properties/prop_area.h"
#include "system_properties/prop_info.h"
#define SERIAL_DIRTY(serial) ((serial)&1)
#define SERIAL_VALUE_LEN(serial) ((serial) >> 24)
static bool is_dir(const char* pathname) {
struct stat info;
if (stat(pathname, &info) == -1) {
return false;
}
return S_ISDIR(info.st_mode);
}
bool SystemProperties::Init(const char* filename) {
// This is called from __libc_init_common, and should leave errno at 0 (http://b/37248982).
ErrnoRestorer errno_restorer;
if (initialized_) {
/* resetprop remove */
// contexts_->ResetAccess();
return true;
}
if (strlen(filename) >= PROP_FILENAME_MAX) {
return false;
}
strcpy(property_filename_, filename);
if (is_dir(property_filename_)) {
if (access("/dev/__properties__/property_info", R_OK) == 0) {
contexts_ = new (contexts_data_) ContextsSerialized();
if (!contexts_->Initialize(false, property_filename_, nullptr)) {
return false;
}
} else {
contexts_ = new (contexts_data_) ContextsSplit();
if (!contexts_->Initialize(false, property_filename_, nullptr)) {
return false;
}
}
} else {
contexts_ = new (contexts_data_) ContextsPreSplit();
if (!contexts_->Initialize(false, property_filename_, nullptr)) {
return false;
}
}
initialized_ = true;
return true;
}
bool SystemProperties::AreaInit(const char* filename, bool* fsetxattr_failed) {
if (strlen(filename) >= PROP_FILENAME_MAX) {
return false;
}
strcpy(property_filename_, filename);
contexts_ = new (contexts_data_) ContextsSerialized();
if (!contexts_->Initialize(true, property_filename_, fsetxattr_failed)) {
return false;
}
initialized_ = true;
return true;
}
uint32_t SystemProperties::AreaSerial() {
if (!initialized_) {
return -1;
}
prop_area* pa = contexts_->GetSerialPropArea();
if (!pa) {
return -1;
}
// Make sure this read fulfilled before __system_property_serial
return atomic_load_explicit(pa->serial(), memory_order_acquire);
}
const prop_info* SystemProperties::Find(const char* name) {
if (!initialized_) {
return nullptr;
}
prop_area* pa = contexts_->GetPropAreaForName(name);
if (!pa) {
async_safe_format_log(ANDROID_LOG_ERROR, "libc", "Access denied finding property \"%s\"", name);
return nullptr;
}
return pa->find(name);
}
static bool is_read_only(const char* name) {
return strncmp(name, "ro.", 3) == 0;
}
int SystemProperties::Read(const prop_info* pi, char* name, char* value) {
while (true) {
uint32_t serial = Serial(pi); // acquire semantics
size_t len = SERIAL_VALUE_LEN(serial);
memcpy(value, pi->value, len + 1);
// TODO: Fix the synchronization scheme here.
// There is no fully supported way to implement this kind
// of synchronization in C++11, since the memcpy races with
// updates to pi, and the data being accessed is not atomic.
// The following fence is unintuitive, but would be the
// correct one if memcpy used memory_order_relaxed atomic accesses.
// In practice it seems unlikely that the generated code would
// would be any different, so this should be OK.
atomic_thread_fence(memory_order_acquire);
if (serial == load_const_atomic(&(pi->serial), memory_order_relaxed)) {
if (name != nullptr) {
size_t namelen = strlcpy(name, pi->name, PROP_NAME_MAX);
if (namelen >= PROP_NAME_MAX) {
async_safe_format_log(ANDROID_LOG_ERROR, "libc",
"The property name length for \"%s\" is >= %d;"
" please use __system_property_read_callback"
" to read this property. (the name is truncated to \"%s\")",
pi->name, PROP_NAME_MAX - 1, name);
}
}
if (is_read_only(pi->name) && pi->is_long()) {
async_safe_format_log(
ANDROID_LOG_ERROR, "libc",
"The property \"%s\" has a value with length %zu that is too large for"
" __system_property_get()/__system_property_read(); use"
" __system_property_read_callback() instead.",
pi->name, strlen(pi->long_value()));
}
return len;
}
}
}
void SystemProperties::ReadCallback(const prop_info* pi,
void (*callback)(void* cookie, const char* name,
const char* value, uint32_t serial),
void* cookie) {
// Read only properties don't need to copy the value to a temporary buffer, since it can never
// change.
if (is_read_only(pi->name)) {
uint32_t serial = Serial(pi);
if (pi->is_long()) {
callback(cookie, pi->name, pi->long_value(), serial);
} else {
callback(cookie, pi->name, pi->value, serial);
}
return;
}
while (true) {
uint32_t serial = Serial(pi); // acquire semantics
size_t len = SERIAL_VALUE_LEN(serial);
char value_buf[len + 1];
memcpy(value_buf, pi->value, len);
value_buf[len] = '\0';
// TODO: see todo in Read function
atomic_thread_fence(memory_order_acquire);
if (serial == load_const_atomic(&(pi->serial), memory_order_relaxed)) {
callback(cookie, pi->name, value_buf, serial);
return;
}
}
}
int SystemProperties::Get(const char* name, char* value) {
const prop_info* pi = Find(name);
if (pi != nullptr) {
return Read(pi, nullptr, value);
} else {
value[0] = 0;
return 0;
}
}
int SystemProperties::Update(prop_info* pi, const char* value, unsigned int len) {
if (len >= PROP_VALUE_MAX) {
return -1;
}
if (!initialized_) {
return -1;
}
prop_area* pa = contexts_->GetSerialPropArea();
if (!pa) {
return -1;
}
uint32_t serial = atomic_load_explicit(&pi->serial, memory_order_relaxed);
serial |= 1;
atomic_store_explicit(&pi->serial, serial, memory_order_relaxed);
// The memcpy call here also races. Again pretend it
// used memory_order_relaxed atomics, and use the analogous
// counterintuitive fence.
atomic_thread_fence(memory_order_release);
strlcpy(pi->value, value, len + 1);
atomic_store_explicit(&pi->serial, (len << 24) | ((serial + 1) & 0xffffff), memory_order_release);
__futex_wake(&pi->serial, INT32_MAX);
atomic_store_explicit(pa->serial(), atomic_load_explicit(pa->serial(), memory_order_relaxed) + 1,
memory_order_release);
__futex_wake(pa->serial(), INT32_MAX);
return 0;
}
int SystemProperties::Add(const char* name, unsigned int namelen, const char* value,
unsigned int valuelen) {
if (valuelen >= PROP_VALUE_MAX && !is_read_only(name)) {
return -1;
}
if (namelen < 1) {
return -1;
}
if (!initialized_) {
return -1;
}
prop_area* serial_pa = contexts_->GetSerialPropArea();
if (serial_pa == nullptr) {
return -1;
}
prop_area* pa = contexts_->GetPropAreaForName(name);
if (!pa) {
async_safe_format_log(ANDROID_LOG_ERROR, "libc", "Access denied adding property \"%s\"", name);
return -1;
}
bool ret = pa->add(name, namelen, value, valuelen);
if (!ret) {
return -1;
}
// There is only a single mutator, but we want to make sure that
// updates are visible to a reader waiting for the update.
atomic_store_explicit(serial_pa->serial(),
atomic_load_explicit(serial_pa->serial(), memory_order_relaxed) + 1,
memory_order_release);
__futex_wake(serial_pa->serial(), INT32_MAX);
return 0;
}
int SystemProperties::Delete(const char *name, bool trim_node) {
if (!initialized_) {
return -1;
}
prop_area* serial_pa = contexts_->GetSerialPropArea();
if (serial_pa == nullptr) {
return -1;
}
prop_area* pa = contexts_->GetPropAreaForName(name);
if (!pa) {
async_safe_format_log(ANDROID_LOG_ERROR, "libc", "Access denied adding property \"%s\"", name);
return -1;
}
bool ret = pa->rm(name, trim_node);
if (!ret) {
return -1;
}
// There is only a single mutator, but we want to make sure that
// updates are visible to a reader waiting for the update.
atomic_store_explicit(serial_pa->serial(),
atomic_load_explicit(serial_pa->serial(), memory_order_relaxed) + 1,
memory_order_release);
__futex_wake(serial_pa->serial(), INT32_MAX);
return 0;
}
// Wait for non-locked serial, and retrieve it with acquire semantics.
uint32_t SystemProperties::Serial(const prop_info* pi) {
uint32_t serial = load_const_atomic(&pi->serial, memory_order_acquire);
while (SERIAL_DIRTY(serial)) {
__futex_wait(const_cast<_Atomic(uint_least32_t)*>(&pi->serial), serial, nullptr);
serial = load_const_atomic(&pi->serial, memory_order_acquire);
}
return serial;
}
uint32_t SystemProperties::WaitAny(uint32_t old_serial) {
uint32_t new_serial;
Wait(nullptr, old_serial, &new_serial, nullptr);
return new_serial;
}
bool SystemProperties::Wait(const prop_info* pi, uint32_t old_serial, uint32_t* new_serial_ptr,
const timespec* relative_timeout) {
// Are we waiting on the global serial or a specific serial?
atomic_uint_least32_t* serial_ptr;
if (pi == nullptr) {
if (!initialized_) {
return -1;
}
prop_area* serial_pa = contexts_->GetSerialPropArea();
if (serial_pa == nullptr) {
return -1;
}
serial_ptr = serial_pa->serial();
} else {
serial_ptr = const_cast<atomic_uint_least32_t*>(&pi->serial);
}
uint32_t new_serial;
do {
int rc;
if ((rc = __futex_wait(serial_ptr, old_serial, relative_timeout)) != 0 && rc == -ETIMEDOUT) {
return false;
}
new_serial = load_const_atomic(serial_ptr, memory_order_acquire);
} while (new_serial == old_serial);
*new_serial_ptr = new_serial;
return true;
}
const prop_info* SystemProperties::FindNth(unsigned n) {
struct find_nth {
const uint32_t sought;
uint32_t current;
const prop_info* result;
explicit find_nth(uint32_t n) : sought(n), current(0), result(nullptr) {
}
static void fn(const prop_info* pi, void* ptr) {
find_nth* self = reinterpret_cast<find_nth*>(ptr);
if (self->current++ == self->sought) self->result = pi;
}
} state(n);
Foreach(find_nth::fn, &state);
return state.result;
}
int SystemProperties::Foreach(void (*propfn)(const prop_info* pi, void* cookie), void* cookie) {
if (!initialized_) {
return -1;
}
contexts_->ForEach(propfn, cookie);
return 0;
}

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@ -1,131 +0,0 @@
/*
* Copyright (C) 2017 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
//#include <sys/_system_properties.h>
#include <_system_properties.h>
#include <system_properties/prop_area.h>
#include <system_properties/system_properties.h>
#include "private/bionic_defs.h"
static SystemProperties system_properties;
static_assert(__is_trivially_constructible(SystemProperties),
"System Properties must be trivially constructable");
// This is public because it was exposed in the NDK. As of 2017-01, ~60 apps reference this symbol.
// It is set to nullptr and never modified.
__BIONIC_WEAK_VARIABLE_FOR_NATIVE_BRIDGE
prop_area* __system_property_area__ = nullptr;
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
int __system_properties_init() {
return system_properties.Init(PROP_FILENAME) ? 0 : -1;
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
int __system_property_set_filename(const char*) {
return -1;
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
int __system_property_area_init() {
bool fsetxattr_failed = false;
return system_properties.AreaInit(PROP_FILENAME, &fsetxattr_failed) && !fsetxattr_failed ? 0 : -1;
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
uint32_t __system_property_area_serial() {
return system_properties.AreaSerial();
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
const prop_info* __system_property_find(const char* name) {
return system_properties.Find(name);
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
int __system_property_read(const prop_info* pi, char* name, char* value) {
return system_properties.Read(pi, name, value);
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
void __system_property_read_callback(const prop_info* pi,
void (*callback)(void* cookie, const char* name,
const char* value, uint32_t serial),
void* cookie) {
return system_properties.ReadCallback(pi, callback, cookie);
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
int __system_property_get(const char* name, char* value) {
return system_properties.Get(name, value);
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
int __system_property_update(prop_info* pi, const char* value, unsigned int len) {
return system_properties.Update(pi, value, len);
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
int __system_property_add(const char* name, unsigned int namelen, const char* value,
unsigned int valuelen) {
return system_properties.Add(name, namelen, value, valuelen);
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
int __system_property_delete(const char *name, bool trim_node) {
return system_properties.Delete(name, trim_node);
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
uint32_t __system_property_serial(const prop_info* pi) {
return system_properties.Serial(pi);
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
uint32_t __system_property_wait_any(uint32_t old_serial) {
return system_properties.WaitAny(old_serial);
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
bool __system_property_wait(const prop_info* pi, uint32_t old_serial, uint32_t* new_serial_ptr,
const timespec* relative_timeout) {
return system_properties.Wait(pi, old_serial, new_serial_ptr, relative_timeout);
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
const prop_info* __system_property_find_nth(unsigned n) {
return system_properties.FindNth(n);
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
int __system_property_foreach(void (*propfn)(const prop_info* pi, void* cookie), void* cookie) {
return system_properties.Foreach(propfn, cookie);
}

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@ -1,317 +0,0 @@
/*
* Copyright (C) 2017 The Android Open Source Project
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* * Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in
* the documentation and/or other materials provided with the
* distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
* OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
* OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
#include <errno.h>
#include <poll.h>
#include <stdatomic.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/uio.h>
#include <sys/un.h>
#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
//#include <sys/_system_properties.h>
#include <_system_properties.h>
#include <unistd.h>
#include <async_safe/log.h>
#include "private/bionic_defs.h"
#include "private/bionic_macros.h"
static const char property_service_socket[] = "/dev/socket/" PROP_SERVICE_NAME;
static const char* kServiceVersionPropertyName = "ro.property_service.version";
#define CHECK(x) /* NOP */
class PropertyServiceConnection {
public:
PropertyServiceConnection() : last_error_(0) {
socket_ = ::socket(AF_LOCAL, SOCK_STREAM | SOCK_CLOEXEC, 0);
if (socket_ == -1) {
last_error_ = errno;
return;
}
const size_t namelen = strlen(property_service_socket);
sockaddr_un addr;
memset(&addr, 0, sizeof(addr));
strlcpy(addr.sun_path, property_service_socket, sizeof(addr.sun_path));
addr.sun_family = AF_LOCAL;
socklen_t alen = namelen + offsetof(sockaddr_un, sun_path) + 1;
if (TEMP_FAILURE_RETRY(connect(socket_, reinterpret_cast<sockaddr*>(&addr), alen)) == -1) {
last_error_ = errno;
close(socket_);
socket_ = -1;
}
}
bool IsValid() {
return socket_ != -1;
}
int GetLastError() {
return last_error_;
}
bool RecvInt32(int32_t* value) {
int result = TEMP_FAILURE_RETRY(recv(socket_, value, sizeof(*value), MSG_WAITALL));
return CheckSendRecvResult(result, sizeof(*value));
}
int socket() {
return socket_;
}
~PropertyServiceConnection() {
if (socket_ != -1) {
close(socket_);
}
}
private:
bool CheckSendRecvResult(int result, int expected_len) {
if (result == -1) {
last_error_ = errno;
} else if (result != expected_len) {
last_error_ = -1;
} else {
last_error_ = 0;
}
return last_error_ == 0;
}
int socket_;
int last_error_;
friend class SocketWriter;
};
class SocketWriter {
public:
explicit SocketWriter(PropertyServiceConnection* connection)
: connection_(connection), iov_index_(0), uint_buf_index_(0) {
}
SocketWriter& WriteUint32(uint32_t value) {
CHECK(uint_buf_index_ < kUintBufSize);
CHECK(iov_index_ < kIovSize);
uint32_t* ptr = uint_buf_ + uint_buf_index_;
uint_buf_[uint_buf_index_++] = value;
iov_[iov_index_].iov_base = ptr;
iov_[iov_index_].iov_len = sizeof(*ptr);
++iov_index_;
return *this;
}
SocketWriter& WriteString(const char* value) {
uint32_t valuelen = strlen(value);
WriteUint32(valuelen);
if (valuelen == 0) {
return *this;
}
CHECK(iov_index_ < kIovSize);
iov_[iov_index_].iov_base = const_cast<char*>(value);
iov_[iov_index_].iov_len = valuelen;
++iov_index_;
return *this;
}
bool Send() {
if (!connection_->IsValid()) {
return false;
}
if (writev(connection_->socket(), iov_, iov_index_) == -1) {
connection_->last_error_ = errno;
return false;
}
iov_index_ = uint_buf_index_ = 0;
return true;
}
private:
static constexpr size_t kUintBufSize = 8;
static constexpr size_t kIovSize = 8;
PropertyServiceConnection* connection_;
iovec iov_[kIovSize];
size_t iov_index_;
uint32_t uint_buf_[kUintBufSize];
size_t uint_buf_index_;
BIONIC_DISALLOW_IMPLICIT_CONSTRUCTORS(SocketWriter);
};
struct prop_msg {
unsigned cmd;
char name[PROP_NAME_MAX];
char value[PROP_VALUE_MAX];
};
static int send_prop_msg(const prop_msg* msg) {
PropertyServiceConnection connection;
if (!connection.IsValid()) {
return connection.GetLastError();
}
int result = -1;
int s = connection.socket();
const int num_bytes = TEMP_FAILURE_RETRY(send(s, msg, sizeof(prop_msg), 0));
if (num_bytes == sizeof(prop_msg)) {
// We successfully wrote to the property server but now we
// wait for the property server to finish its work. It
// acknowledges its completion by closing the socket so we
// poll here (on nothing), waiting for the socket to close.
// If you 'adb shell setprop foo bar' you'll see the POLLHUP
// once the socket closes. Out of paranoia we cap our poll
// at 250 ms.
pollfd pollfds[1];
pollfds[0].fd = s;
pollfds[0].events = 0;
const int poll_result = TEMP_FAILURE_RETRY(poll(pollfds, 1, 250 /* ms */));
if (poll_result == 1 && (pollfds[0].revents & POLLHUP) != 0) {
result = 0;
} else {
// Ignore the timeout and treat it like a success anyway.
// The init process is single-threaded and its property
// service is sometimes slow to respond (perhaps it's off
// starting a child process or something) and thus this
// times out and the caller thinks it failed, even though
// it's still getting around to it. So we fake it here,
// mostly for ctl.* properties, but we do try and wait 250
// ms so callers who do read-after-write can reliably see
// what they've written. Most of the time.
// TODO: fix the system properties design.
async_safe_format_log(ANDROID_LOG_WARN, "libc",
"Property service has timed out while trying to set \"%s\" to \"%s\"",
msg->name, msg->value);
result = 0;
}
}
return result;
}
static constexpr uint32_t kProtocolVersion1 = 1;
static constexpr uint32_t kProtocolVersion2 = 2; // current
static atomic_uint_least32_t g_propservice_protocol_version(0);
static void detect_protocol_version() {
char value[PROP_VALUE_MAX];
if (__system_property_get(kServiceVersionPropertyName, value) == 0) {
g_propservice_protocol_version = kProtocolVersion1;
async_safe_format_log(ANDROID_LOG_WARN, "libc",
"Using old property service protocol (\"%s\" is not set)",
kServiceVersionPropertyName);
} else {
uint32_t version = static_cast<uint32_t>(atoll(value));
if (version >= kProtocolVersion2) {
g_propservice_protocol_version = kProtocolVersion2;
} else {
async_safe_format_log(ANDROID_LOG_WARN, "libc",
"Using old property service protocol (\"%s\"=\"%s\")",
kServiceVersionPropertyName, value);
g_propservice_protocol_version = kProtocolVersion1;
}
}
}
__BIONIC_WEAK_FOR_NATIVE_BRIDGE
int __system_property_set(const char* key, const char* value) {
if (key == nullptr) return -1;
if (value == nullptr) value = "";
if (g_propservice_protocol_version == 0) {
detect_protocol_version();
}
if (g_propservice_protocol_version == kProtocolVersion1) {
// Old protocol does not support long names or values
if (strlen(key) >= PROP_NAME_MAX) return -1;
if (strlen(value) >= PROP_VALUE_MAX) return -1;
prop_msg msg;
memset(&msg, 0, sizeof msg);
msg.cmd = PROP_MSG_SETPROP;
strlcpy(msg.name, key, sizeof msg.name);
strlcpy(msg.value, value, sizeof msg.value);
return send_prop_msg(&msg);
} else {
// New protocol only allows long values for ro. properties only.
if (strlen(value) >= PROP_VALUE_MAX && strncmp(key, "ro.", 3) != 0) return -1;
// Use proper protocol
PropertyServiceConnection connection;
if (!connection.IsValid()) {
errno = connection.GetLastError();
async_safe_format_log(
ANDROID_LOG_WARN, "libc",
"Unable to set property \"%s\" to \"%s\": connection failed; errno=%d (%s)", key, value,
errno, strerror(errno));
return -1;
}
SocketWriter writer(&connection);
if (!writer.WriteUint32(PROP_MSG_SETPROP2).WriteString(key).WriteString(value).Send()) {
errno = connection.GetLastError();
async_safe_format_log(ANDROID_LOG_WARN, "libc",
"Unable to set property \"%s\" to \"%s\": write failed; errno=%d (%s)",
key, value, errno, strerror(errno));
return -1;
}
int result = -1;
if (!connection.RecvInt32(&result)) {
errno = connection.GetLastError();
async_safe_format_log(ANDROID_LOG_WARN, "libc",
"Unable to set property \"%s\" to \"%s\": recv failed; errno=%d (%s)",
key, value, errno, strerror(errno));
return -1;
}
if (result != PROP_SUCCESS) {
async_safe_format_log(ANDROID_LOG_WARN, "libc",
"Unable to set property \"%s\" to \"%s\": error code: 0x%x", key, value,
result);
return -1;
}
return 0;
}
}

View File

@ -5,6 +5,7 @@
int setprop(const char *name, const char *value, bool prop_svc = true);
std::string getprop(const char *name, bool persist = false);
std::string getpropcontext(const char *name);
void getprops(void (*callback)(const char *, const char *, void *),
void *cookie = nullptr, bool persist = false);
int delprop(const char *name, bool persist = false);

View File

@ -3,7 +3,8 @@
#include <string>
#include <map>
#include <system_properties.h>
#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
#include <api/_system_properties.h>
#define PERSISTENT_PROPERTY_DIR "/data/property"

View File

@ -6,11 +6,6 @@
#include <resetprop.hpp>
#include <base.hpp>
#undef __INTRODUCED_IN
#define __INTRODUCED_IN(...)
#define _REALLY_INCLUDE_SYS__SYSTEM_PROPERTIES_H_
#include <_system_properties.h>
#include "prop.hpp"
using namespace std;
@ -65,6 +60,8 @@ Flags:
(this flag only affects setprop)
-p read/write props from/to persistent storage
(this flag only affects getprop and delprop)
-Z show property contexts instead of values
(this flag only affects getprop)
)EOF", arg0);
exit(1);
@ -118,6 +115,7 @@ static void read_prop(const prop_info *pi, void *cb) {
struct sysprop_stub {
virtual int setprop(const char *name, const char *value, bool trigger) { return 1; }
virtual string getprop(const char *name, bool persist) { return string(); }
virtual string getcontext(const char *name) { return string(); }
virtual void getprops(void (*callback)(const char *, const char *, void *),
void *cookie, bool persist) {}
virtual int delprop(const char *name, bool persist) { return 1; }
@ -211,6 +209,18 @@ struct resetprop : public sysprop {
return val;
}
string getcontext(const char *name) override {
if (!check_legal_property_name(name))
return "";
auto val = __system_property_get_context(name);
if (val == nullptr) {
LOGD("resetprop: prop [%s] does not support context\n", name);
return "";
}
LOGD("resetprop: getcontext [%s]: [%s]\n", name, val);
return val;
}
void getprops(void (*callback)(const char *, const char *, void *),
void *cookie, bool persist) override {
prop_list list;
@ -270,10 +280,20 @@ static void print_props(bool persist) {
}, nullptr, persist);
}
static void print_props_context() {
getprops([](const char *name, const char *, auto) {
printf("[%s]: [%s]\n", name, getpropcontext(name).data());
}, nullptr, false);
}
string getprop(const char *name, bool persist) {
return get_impl()->getprop(name, persist);
}
string getpropcontext(const char *name) {
return get_impl()->getcontext(name);
}
void getprops(void (*callback)(const char *, const char *, void *), void *cookie, bool persist) {
get_impl()->getprops(callback, cookie, persist);
}
@ -299,6 +319,7 @@ int resetprop_main(int argc, char *argv[]) {
bool prop_svc = true;
bool persist = false;
bool verbose = false;
bool context = false;
char *argv0 = argv[0];
--argc;
@ -326,6 +347,9 @@ int resetprop_main(int argc, char *argv[]) {
case 'n':
prop_svc = false;
continue;
case 'Z':
context = true;
continue;
case '\0':
break;
case 'h':
@ -342,10 +366,13 @@ int resetprop_main(int argc, char *argv[]) {
switch (argc) {
case 0:
print_props(persist);
if (context)
print_props_context();
else
print_props(persist);
return 0;
case 1: {
string prop = getprop(argv[0], persist);
string prop = context ? getpropcontext(argv[0]) : getprop(argv[0], persist);
if (prop.empty())
return 1;
printf("%s\n", prop.data());