Replace readlink calls with a safer version that guarantees NULL-termination.

This patch is part of a bigger patch that helps merging the breakpad code
with the modified version in Chromium OS.

Specifically, this patch makes the following changes:
1. Add a SafeReadLink function that wraps sys_readlink() to resolve a
   symbolic link but guarantees the result is NULL-terminated on success.
2. Refactor other source code to use SafeReadLink instead of readlink()
   or sys_readlink().

BUG=455
TEST=Tested the following:
1. Build on 32-bit and 64-bit Linux with gcc 4.4.3 and gcc 4.6.
2. Build on Mac OS X 10.6.8 with gcc 4.2 and clang 3.0 (with latest gmock).
3. All unit tests pass.
4. Run minidump-2-core to covnert a minidump file to a core file.
Review URL: http://breakpad.appspot.com/334001

git-svn-id: http://google-breakpad.googlecode.com/svn/trunk@896 4c0a9323-5329-0410-9bdc-e9ce6186880e

1 files changed, 3 insertions, 3 deletions

diff --git a/src/common/linux/file_id_unittest.cc b/src/common/linux/file_id_unittest.cc
index 977f97d2..94bc80e4 100644
--- a/src/common/linux/file_id_unittest.cc
+++ b/src/common/linux/file_id_unittest.cc
@@ -33,12 +33,14 @@
 #include <stdlib.h>
 
 #include "common/linux/file_id.h"
+#include "common/linux/safe_readlink.h"
 #include "common/linux/synth_elf.h"
 #include "common/test_assembler.h"
 #include "common/tests/auto_tempdir.h"
 #include "breakpad_googletest_includes.h"
 
 using namespace google_breakpad;
+using google_breakpad::SafeReadLink;
 using google_breakpad::synth_elf::BuildIDNote;
 using google_breakpad::synth_elf::ELF;
 using google_breakpad::test_assembler::kLittleEndian;
@@ -61,9 +63,7 @@ TEST(FileIDStripTest, StripSelf) {
   // FileID::ElfFileIdentifier, then make a copy of this binary,
   // strip it, and ensure that the result is the same.
   char exe_name[PATH_MAX];
-  ssize_t len = readlink("/proc/self/exe", exe_name, PATH_MAX - 1);
-  ASSERT_NE(len, -1);
-  exe_name[len] = '\0';
+  ASSERT_TRUE(SafeReadLink("/proc/self/exe", exe_name));
 
   // copy our binary to a temp file, and strip it
   AutoTempDir temp_dir;