Improve curl example

- Update sandbox policy (bring back inclusion of `/lib` to enable glibc
  resolver
- Better error handling using new `curl_util` library

Signed-off-by: Christian Blichmann <cblichmann@google.com>

oss-internship-2020/curl/CMakeLists.txt

@@ -45,6 +45,7 @@ add_subdirectory(
 
 # Generate SAPI header
 add_sapi_library(curl_sapi
+  SOURCES sandbox.h
 
   # List of all the methods in https://curl.haxx.se/libcurl/c/allfuncs.html
   # Some are added or modified because the original ones are not supported
@@ -127,10 +128,16 @@ add_sapi_library(curl_sapi
 
   NAMESPACE curl
 )
-
-# Include generated SAPI header
 target_include_directories(curl_sapi INTERFACE
-  "${PROJECT_BINARY_DIR}"
+  "${PROJECT_BINARY_DIR}" # Include generated SAPI header
+)
+
+add_library(curl_util STATIC
+  curl_util.cc
+  curl_util.h
+)
+target_link_libraries(curl_util PUBLIC
+  curl_sapi
 )
 
 # Add examples

oss-internship-2020/curl/curl_util.cc

@@ -0,0 +1,37 @@
+// Copyright 2021 Google LLC
+//
+// 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 "curl_util.h"  // NOLINT(build/include)
+
+#include "absl/status/statusor.h"
+#include "absl/strings/str_cat.h"
+
+namespace curl {
+
+std::string StrError(curl::CurlApi* api, int curl_error) {
+  absl::StatusOr<void*> remote_error_message =
+      api->curl_easy_strerror(static_cast<CURLcode>(curl_error));
+  if (!remote_error_message.ok()) {
+    return absl::StrCat("Code ", curl_error, " (curl_easy_strerror failed)");
+  }
+
+  absl::StatusOr<std::string> error_message =
+      api->sandbox()->GetCString(sapi::v::RemotePtr(*remote_error_message));
+  if (!error_message.ok()) {
+    return absl::StrCat("Code ", curl_error, " (error getting error message)");
+  }
+  return *error_message;
+}
+
+}  // namespace curl

oss-internship-2020/curl/curl_util.h

@@ -0,0 +1,30 @@
+// Copyright 2021 Google LLC
+//
+// 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 CURL_UTIL_H_
+#define CURL_UTIL_H_
+
+#include <string>
+
+#include "curl_sapi.sapi.h"  // NOLINT(build/include)
+
+namespace curl {
+
+// Calls into the sandbox to retrieve the error message for the curl error code
+// in curl_error.
+std::string StrError(curl::CurlApi* api, int curl_error);
+
+}  // namespace curl
+
+#endif  // CURL_UTIL_H_

oss-internship-2020/curl/examples/CMakeLists.txt

@@ -22,6 +22,7 @@ add_executable(example1
 )
 target_link_libraries(example1 PRIVATE
   curl_sapi
+  curl_util
   sapi::sapi
 )
 
@@ -32,6 +33,7 @@ add_executable(example2
 )
 target_link_libraries(example2 PRIVATE
   curl_sapi
+  curl_util
   sapi::sapi
 )
 
@@ -42,6 +44,7 @@ add_executable(example3
 )
 target_link_libraries(example3 PRIVATE
   curl_sapi
+  curl_util
   sapi::sapi
 )
 
@@ -52,6 +55,7 @@ add_executable(example4
 )
 target_link_libraries(example4 PRIVATE
   curl_sapi
+  curl_util
   sapi::sapi
 )
 
@@ -62,6 +66,7 @@ add_executable(example5
 )
 target_link_libraries(example5 PRIVATE
   curl_sapi
+  curl_util
   sapi::sapi
 )
 
@@ -72,5 +77,6 @@ add_executable(example6
 )
 target_link_libraries(example6 PRIVATE
   curl_sapi
+  curl_util
   sapi::sapi
 )

oss-internship-2020/curl/examples/example1.cc

@@ -17,8 +17,11 @@
 
 #include <cstdlib>
 
+#include "../curl_util.h"  // NOLINT(build/include)
 #include "../sandbox.h"    // NOLINT(build/include)
 #include "absl/strings/str_cat.h"
+#include "curl_sapi.sapi.h"  // NOLINT(build/include)
+#include "sandboxed_api/util/status_macros.h"
 
 namespace {
 
@@ -33,7 +36,7 @@ absl::Status Example1() {
   SAPI_ASSIGN_OR_RETURN(curl_handle, api.curl_easy_init());
   sapi::v::RemotePtr curl(curl_handle);
   if (!curl_handle) {
-    return absl::UnavailableError("curl_easy_init failed: curl is NULL");
+    return absl::UnknownError("curl_easy_init failed: Invalid curl handle");
   }
 
   int curl_code;
@@ -44,8 +47,8 @@ absl::Status Example1() {
       curl_code,
       api.curl_easy_setopt_ptr(&curl, curl::CURLOPT_URL, url.PtrBefore()));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_setopt_ptr failed: ", curl_code));
+    return absl::UnknownError(absl::StrCat("curl_easy_setopt_ptr failed: ",
+                                           curl::StrError(&api, curl_code)));
   }
 
   // Set the library to follow a redirection
@@ -53,8 +56,8 @@ absl::Status Example1() {
       curl_code,
       api.curl_easy_setopt_long(&curl, curl::CURLOPT_FOLLOWLOCATION, 1l));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_setopt_long failed: ", curl_code));
+    return absl::UnknownError(absl::StrCat("curl_easy_setopt_long failed: ",
+                                           curl::StrError(&api, curl_code)));
   }
 
   // Disable authentication of peer certificate
@@ -62,15 +65,15 @@ absl::Status Example1() {
       curl_code,
       api.curl_easy_setopt_long(&curl, curl::CURLOPT_SSL_VERIFYPEER, 0l));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_setopt_long failed: ", curl_code));
+    return absl::UnknownError(absl::StrCat("curl_easy_setopt_long failed: ",
+                                           curl::StrError(&api, curl_code)));
   }
 
   // Perform the request
   SAPI_ASSIGN_OR_RETURN(curl_code, api.curl_easy_perform(&curl));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_perform failed: ", curl_code));
+    return absl::UnknownError(absl::StrCat("curl_easy_perform failed: ",
+                                           curl::StrError(&api, curl_code)));
   }
 
   // Cleanup curl

oss-internship-2020/curl/examples/example2.cc

@@ -16,10 +16,11 @@
 // HTTP GET request using callbacks
 
 #include <cstdlib>
-#include <iostream>
 
+#include "../curl_util.h"  // NOLINT(build/include)
 #include "../sandbox.h"    // NOLINT(build/include)
 #include "absl/strings/str_cat.h"
+#include "sandboxed_api/util/status_macros.h"
 
 namespace {
 
@@ -40,7 +41,7 @@ absl::Status Example2() {
   SAPI_ASSIGN_OR_RETURN(curl_handle, api.curl_easy_init());
   sapi::v::RemotePtr curl(curl_handle);
   if (!curl_handle) {
-    return absl::UnavailableError("curl_easy_init failed: curl is NULL");
+    return absl::UnavailableError("curl_easy_init failed: Invalid curl handle");
   }
 
   int curl_code;
@@ -51,8 +52,8 @@ absl::Status Example2() {
       curl_code,
       api.curl_easy_setopt_ptr(&curl, curl::CURLOPT_URL, url.PtrBefore()));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_setopt_ptr failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_easy_setopt_ptr failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Set WriteMemoryCallback as the write function
@@ -60,8 +61,8 @@ absl::Status Example2() {
       curl_code, api.curl_easy_setopt_ptr(&curl, curl::CURLOPT_WRITEFUNCTION,
                                           &write_to_memory));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_setopt_ptr failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_easy_setopt_ptr failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Pass 'chunk' struct to the callback function
@@ -70,8 +71,8 @@ absl::Status Example2() {
                         api.curl_easy_setopt_ptr(&curl, curl::CURLOPT_WRITEDATA,
                                                  chunk.PtrBoth()));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_setopt_ptr failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_easy_setopt_ptr failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Set a user agent
@@ -80,15 +81,15 @@ absl::Status Example2() {
                         api.curl_easy_setopt_ptr(&curl, curl::CURLOPT_USERAGENT,
                                                  user_agent.PtrBefore()));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_setopt_ptr failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_easy_setopt_ptr failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Perform the request
   SAPI_ASSIGN_OR_RETURN(curl_code, api.curl_easy_perform(&curl));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_perform failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_easy_perform failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Retrieve memory size

oss-internship-2020/curl/examples/example3.cc

@@ -17,7 +17,11 @@
 
 #include <cstdlib>
 
+#include "../curl_util.h"  // NOLINT(build/include)
 #include "../sandbox.h"    // NOLINT(build/include)
+#include "absl/strings/str_cat.h"
+#include "curl_sapi.sapi.h"  // NOLINT(build/include)
+#include "sandboxed_api/util/status_macros.h"
 
 namespace {
 
@@ -25,9 +29,9 @@ class CurlSapiSandboxEx3 : public curl::CurlSapiSandbox {
  public:
   CurlSapiSandboxEx3(std::string ssl_certificate, std::string ssl_key,
                      std::string ca_certificates)
-      : ssl_certificate(ssl_certificate),
-        ssl_key(ssl_key),
-        ca_certificates(ca_certificates) {}
+      : ssl_certificate(std::move(ssl_certificate)),
+        ssl_key(std::move(ssl_key)),
+        ca_certificates(std::move(ca_certificates)) {}
 
  private:
   std::unique_ptr<sandbox2::Policy> ModifyPolicy(
@@ -35,11 +39,9 @@ class CurlSapiSandboxEx3 : public curl::CurlSapiSandbox {
     // Add the syscalls and files missing in CurlSandbox to a new PolicyBuilder
     auto policy_builder = std::make_unique<sandbox2::PolicyBuilder>();
     (*policy_builder)
-        .AllowFutexOp(FUTEX_WAIT_PRIVATE)
         .AllowGetPIDs()
         .AllowGetRandom()
         .AllowHandleSignals()
-        .AllowSyscall(__NR_sysinfo)
         .AddFile(ssl_certificate)
         .AddFile(ssl_key)
         .AddFile(ca_certificates);
@@ -52,9 +54,10 @@ class CurlSapiSandboxEx3 : public curl::CurlSapiSandbox {
   std::string ca_certificates;
 };
 
-absl::Status Example3(std::string ssl_certificate, std::string ssl_key,
-                      std::string ssl_key_password,
-                      std::string ca_certificates) {
+absl::Status Example3(const std::string& ssl_certificate,
+                      const std::string& ssl_key,
+                      const std::string& ssl_key_password,
+                      const std::string& ca_certificates) {
   // Initialize sandbox2 and sapi
   CurlSapiSandboxEx3 sandbox(ssl_certificate, ssl_key, ca_certificates);
   SAPI_RETURN_IF_ERROR(sandbox.Init());
@@ -65,8 +68,8 @@ absl::Status Example3(std::string ssl_certificate, std::string ssl_key,
   // Initialize curl (CURL_GLOBAL_DEFAULT = 3)
   SAPI_ASSIGN_OR_RETURN(curl_code, api.curl_global_init(3l));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_global_init failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_global_init failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Initialize curl easy handle
@@ -74,7 +77,7 @@ absl::Status Example3(std::string ssl_certificate, std::string ssl_key,
   SAPI_ASSIGN_OR_RETURN(curl_handle, api.curl_easy_init());
   sapi::v::RemotePtr curl(curl_handle);
   if (!curl_handle) {
-    return absl::UnavailableError("curl_easy_init failed: curl is NULL");
+    return absl::UnavailableError("curl_easy_init failed: Invalid curl handle");
   }
 
   // Specify URL to get (using HTTPS)
@@ -83,8 +86,8 @@ absl::Status Example3(std::string ssl_certificate, std::string ssl_key,
       curl_code,
       api.curl_easy_setopt_ptr(&curl, curl::CURLOPT_URL, url.PtrBefore()));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_setopt_ptr failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_easy_setopt_ptr failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Set the SSL certificate type to "PEM"
@@ -93,8 +96,8 @@ absl::Status Example3(std::string ssl_certificate, std::string ssl_key,
       curl_code, api.curl_easy_setopt_ptr(&curl, curl::CURLOPT_SSLCERTTYPE,
                                           ssl_cert_type.PtrBefore()));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_setopt_ptr failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_easy_setopt_ptr failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Set the certificate for client authentication
@@ -103,8 +106,8 @@ absl::Status Example3(std::string ssl_certificate, std::string ssl_key,
       curl_code, api.curl_easy_setopt_ptr(&curl, curl::CURLOPT_SSLCERT,
                                           sapi_ssl_certificate.PtrBefore()));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_setopt_ptr failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_easy_setopt_ptr failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Set the private key for client authentication
@@ -113,8 +116,8 @@ absl::Status Example3(std::string ssl_certificate, std::string ssl_key,
                         api.curl_easy_setopt_ptr(&curl, curl::CURLOPT_SSLKEY,
                                                  sapi_ssl_key.PtrBefore()));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_setopt_ptr failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_easy_setopt_ptr failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Set the password used to protect the private key
@@ -123,8 +126,8 @@ absl::Status Example3(std::string ssl_certificate, std::string ssl_key,
       curl_code, api.curl_easy_setopt_ptr(&curl, curl::CURLOPT_KEYPASSWD,
                                           sapi_ssl_key_password.PtrBefore()));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_setopt_ptr failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_easy_setopt_ptr failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Set the file with the certificates vaildating the server
@@ -133,8 +136,8 @@ absl::Status Example3(std::string ssl_certificate, std::string ssl_key,
       curl_code, api.curl_easy_setopt_ptr(&curl, curl::CURLOPT_CAINFO,
                                           sapi_ca_certificates.PtrBefore()));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_setopt_ptr failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_easy_setopt_ptr failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Verify the authenticity of the server
@@ -142,15 +145,15 @@ absl::Status Example3(std::string ssl_certificate, std::string ssl_key,
       curl_code,
       api.curl_easy_setopt_long(&curl, curl::CURLOPT_SSL_VERIFYPEER, 1L));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_setopt_long failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_easy_setopt_long failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Perform the request
   SAPI_ASSIGN_OR_RETURN(curl_code, api.curl_easy_perform(&curl));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_perform failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_easy_perform failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Cleanup curl easy handle

oss-internship-2020/curl/examples/example4.cc

@@ -17,10 +17,11 @@
 
 #include <cstdlib>
 
+#include "../curl_util.h"  // NOLINT(build/include)
 #include "../sandbox.h"    // NOLINT(build/include)
-#include "curl_sapi.sapi.h"  // NOLINT(build/include)
-#include "sandboxed_api/util/flag.h"
 #include "absl/strings/str_cat.h"
+#include "curl_sapi.sapi.h"  // NOLINT(build/include)
+#include "sandboxed_api/util/status_macros.h"
 
 namespace {
 
@@ -38,8 +39,8 @@ absl::Status Example4() {
   // Initialize curl (CURL_GLOBAL_DEFAULT = 3)
   SAPI_ASSIGN_OR_RETURN(curl_code, api.curl_global_init(3l));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_global_init failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_global_init failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Initialize http_handle
@@ -47,7 +48,7 @@ absl::Status Example4() {
   SAPI_ASSIGN_OR_RETURN(curl_handle, api.curl_easy_init());
   sapi::v::RemotePtr http_handle(curl_handle);
   if (!curl_handle) {
-    return absl::UnavailableError("curl_easy_init failed: curl is NULL");
+    return absl::UnavailableError("curl_easy_init failed: Invalid curl handle");
   }
 
   // Specify URL to get
@@ -56,8 +57,8 @@ absl::Status Example4() {
       curl_code, api.curl_easy_setopt_ptr(&http_handle, curl::CURLOPT_URL,
                                           url.PtrBefore()));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_setopt_ptr failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_easy_setopt_ptr failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Initialize multi_handle
@@ -66,15 +67,15 @@ absl::Status Example4() {
   sapi::v::RemotePtr multi_handle(curlm_handle);
   if (!curlm_handle) {
     return absl::UnavailableError(
-        "curl_multi_init failed: multi_handle is NULL");
+        "curl_multi_init failed: multi_handle is invalid");
   }
 
   // Add http_handle to the multi stack
   SAPI_ASSIGN_OR_RETURN(curl_code,
                         api.curl_multi_add_handle(&multi_handle, &http_handle));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_multi_add_handle failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_multi_add_handle failed: ", curl::StrError(&api, curl_code)));
   }
 
   while (still_running.GetValue()) {
@@ -85,8 +86,8 @@ absl::Status Example4() {
         curl_code,
         api.curl_multi_perform(&multi_handle, still_running.PtrBoth()));
     if (curl_code != 0) {
-      return absl::UnavailableError(
-          absl::StrCat("curl_mutli_perform failed: ", curl_code));
+      return absl::UnavailableError(absl::StrCat(
+          "curl_mutli_perform failed: ", curl::StrError(&api, curl_code)));
     }
 
     if (still_running.GetValue()) {
@@ -96,8 +97,8 @@ absl::Status Example4() {
           curl_code, api.curl_multi_poll_sapi(&multi_handle, &null_ptr, 0, 1000,
                                               numfds.PtrBoth()));
       if (curl_code != 0) {
-        return absl::UnavailableError(
-            absl::StrCat("curl_multi_poll_sapi failed: ", curl_code));
+        return absl::UnavailableError(absl::StrCat(
+            "curl_multi_poll_sapi failed: ", curl::StrError(&api, curl_code)));
       }
     }
   }
@@ -106,8 +107,8 @@ absl::Status Example4() {
   SAPI_ASSIGN_OR_RETURN(
       curl_code, api.curl_multi_remove_handle(&multi_handle, &http_handle));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_multi_remove_handle failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_multi_remove_handle failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Cleanup http_handle
@@ -116,8 +117,8 @@ absl::Status Example4() {
   // Cleanup multi_handle
   SAPI_ASSIGN_OR_RETURN(curl_code, api.curl_multi_cleanup(&multi_handle));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_multi_cleanup failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_multi_cleanup failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Cleanup curl

oss-internship-2020/curl/examples/example5.cc

@@ -19,8 +19,11 @@
 #include <future>  // NOLINT(build/c++11)
 #include <thread>  // NOLINT(build/c++11)
 
+#include "../curl_util.h"  // NOLINT(build/include)
 #include "../sandbox.h"    // NOLINT(build/include)
 #include "absl/strings/str_cat.h"
+#include "curl_sapi.sapi.h"  // NOLINT(build/include)
+#include "sandboxed_api/util/status_macros.h"
 
 namespace {
 
@@ -30,7 +33,7 @@ absl::Status pull_one_url(const std::string& url, curl::CurlApi& api) {
   SAPI_ASSIGN_OR_RETURN(curl_handle, api.curl_easy_init());
   sapi::v::RemotePtr curl(curl_handle);
   if (!curl_handle) {
-    return absl::UnavailableError("curl_easy_init failed: curl is NULL");
+    return absl::UnavailableError("curl_easy_init failed: Invalid curl handle");
   }
 
   int curl_code;
@@ -41,15 +44,15 @@ absl::Status pull_one_url(const std::string& url, curl::CurlApi& api) {
       curl_code,
       api.curl_easy_setopt_ptr(&curl, curl::CURLOPT_URL, sapi_url.PtrBefore()));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_setopt_ptr failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_easy_setopt_ptr failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Perform the request
   SAPI_ASSIGN_OR_RETURN(curl_code, api.curl_easy_perform(&curl));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_easy_perform failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_easy_perform failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Cleanup curl easy handle
@@ -58,10 +61,6 @@ absl::Status pull_one_url(const std::string& url, curl::CurlApi& api) {
   return absl::OkStatus();
 }
 
-const std::vector<std::string> urls = {
-    "http://example.com", "http://example.edu", "http://example.net",
-    "http://example.org"};
-
 absl::Status Example5() {
   // Initialize sandbox2 and sapi
   curl::CurlSapiSandbox sandbox;
@@ -73,11 +72,14 @@ absl::Status Example5() {
   // Initialize curl (CURL_GLOBAL_DEFAULT = 3)
   SAPI_ASSIGN_OR_RETURN(curl_code, api.curl_global_init(3l));
   if (curl_code != 0) {
-    return absl::UnavailableError(
-        absl::StrCat("curl_global_init failed: ", curl_code));
+    return absl::UnavailableError(absl::StrCat(
+        "curl_global_init failed: ", curl::StrError(&api, curl_code)));
   }
 
   // Create the threads (by using futures)
+  const std::vector<std::string> urls = {
+      "http://example.com", "http://example.edu", "http://example.net",
+      "http://example.org"};
   std::vector<std::future<absl::Status>> futures;
   for (auto& url : urls) {
     futures.emplace_back(

oss-internship-2020/curl/examples/example6.cc

@@ -17,8 +17,12 @@
 
 #include <cstdlib>
 
+#include "../curl_util.h"  // NOLINT(build/include)
 #include "../sandbox.h"    // NOLINT(build/include)
+#include "absl/strings/str_cat.h"
+#include "curl_sapi.sapi.h"  // NOLINT(build/include)
 #include "sandboxed_api/transaction.h"
+#include "sandboxed_api/util/status_macros.h"
 
 namespace {
 

oss-internship-2020/curl/sandbox.h

@@ -29,16 +29,17 @@ namespace curl {
 class CurlSapiSandbox : public curl::CurlSandbox {
  protected:
   std::unique_ptr<sandbox2::Policy> ModifyPolicy(
-      sandbox2::PolicyBuilder* policy_builder) override {
+      sandbox2::PolicyBuilder*) override {
     // Return a new policy
     return sandbox2::PolicyBuilder()
         .AllowDynamicStartup()
         .AllowExit()
         .AllowFork()
+        .AllowFutexOp(FUTEX_WAIT_PRIVATE)
         .AllowFutexOp(FUTEX_WAKE_PRIVATE)
+        .AllowFutexOp(FUTEX_REQUEUE_PRIVATE)
         .AllowMmap()
         .AllowOpen()
-        .AllowRead()
         .AllowSafeFcntl()
         .AllowWrite()
         .AllowAccess()
@@ -62,6 +63,7 @@ class CurlSapiSandbox : public curl::CurlSandbox {
             __NR_socket,
             __NR_sysinfo,
         })
+        .AddDirectory("/lib")
         .AllowUnrestrictedNetworking()
         .BuildOrDie();
   }