Use realpath() to find the path to the extension unpack dir on posix systems.

Extensions are unpacked by a sandboxed utility process.  The sandbox forbids file access outside the directory the extension will be unpacked in.  If the path to that directory contains a symbolic link, then unpacking will fail because following the link will cause file system access outside the sandbox path.  Use realpath() to get a symlink free path to the directory where the extension will be unpacked.

A similar issue exists on windows, with junctions instead of symlinks.  This will be fixed in another change.

BUG=13044,35198
TEST=FileUtilTest.RealPath

Review URL: http://codereview.chromium.org/2001013

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@47032 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 10 insertions, 0 deletions

diff --git a/base/file_util_posix.cc b/base/file_util_posix.cc
index d9cbe09..9db41fe 100644
--- a/base/file_util_posix.cc
+++ b/base/file_util_posix.cc
@@ -14,6 +14,7 @@
 #include <string.h>
 #include <sys/errno.h>
 #include <sys/mman.h>
+#include <sys/param.h>
 #include <sys/stat.h>
 #include <sys/time.h>
 #include <sys/types.h>
@@ -735,6 +736,15 @@ bool HasFileBeenModifiedSince(const FileEnumerator::FindInfo& find_info,
   return find_info.stat.st_mtime >= cutoff_time.ToTimeT();
 }
 
+bool RealPath(const FilePath& path, FilePath* real_path) {
+  FilePath::CharType buf[PATH_MAX];
+  if (!realpath(path.value().c_str(), buf))
+    return false;
+
+  *real_path = FilePath(buf);
+  return true;
+}
+
 #if !defined(OS_MACOSX)
 bool GetTempDir(FilePath* path) {
   const char* tmp = getenv("TMPDIR");