From ed0086eb66f49f54fd3a8502fb781554131ff3a9 Mon Sep 17 00:00:00 2001
From: Christian Blichmann <cblichmann@google.com>
Date: Mon, 14 Sep 2020 01:18:09 -0700
Subject: [PATCH] Fix dynamic binary startup on PPC and newer glibc (> 2.19)

This allows the `_llseek` syscall when it is defined.

PiperOrigin-RevId: 331498182
Change-Id: I2760b264e3a82000b38d278a9c280501a3dbc724
---
 sandboxed_api/sandbox2/policybuilder.cc | 6 +++++-
 sandboxed_api/sandbox2/stack_trace.cc   | 3 +++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/sandboxed_api/sandbox2/policybuilder.cc b/sandboxed_api/sandbox2/policybuilder.cc
index c0bfd41..678677d 100644
--- a/sandboxed_api/sandbox2/policybuilder.cc
+++ b/sandboxed_api/sandbox2/policybuilder.cc
@@ -533,7 +533,11 @@ PolicyBuilder& PolicyBuilder::AllowStaticStartup() {
 PolicyBuilder& PolicyBuilder::AllowDynamicStartup() {
   AllowRead();
   AllowStat();
-  AllowSyscalls({__NR_lseek, __NR_close, __NR_munmap});
+  AllowSyscalls({__NR_lseek,
+#ifdef __NR__llseek
+                 __NR__llseek,  // Newer glibc on PPC
+#endif
+                 __NR_close, __NR_munmap});
   AddPolicyOnSyscall(__NR_mprotect, {
                                         ARG_32(2),
                                         JEQ32(PROT_READ, ALLOW),
diff --git a/sandboxed_api/sandbox2/stack_trace.cc b/sandboxed_api/sandbox2/stack_trace.cc
index 868b89e..ef494b1 100644
--- a/sandboxed_api/sandbox2/stack_trace.cc
+++ b/sandboxed_api/sandbox2/stack_trace.cc
@@ -86,6 +86,9 @@ std::unique_ptr<Policy> StackTracePeer::GetPolicy(pid_t target_pid,
       // libunwind
       .AllowSyscall(__NR_fstat)
       .AllowSyscall(__NR_lseek)
+#ifdef __NR__llseek
+      .AllowSyscall(__NR__llseek)  // Newer glibc on PPC
+#endif
       .AllowSyscall(__NR_mincore)
       .AllowSyscall(__NR_mprotect)
       .AllowSyscall(__NR_munmap)