Fix timegm behavior for android.

time_t on android is 32 bit.
We should detect overflow and return -1.

BUG=
TEST=


Review URL: http://codereview.chromium.org/8976004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@114762 0039d316-1c4b-4281-b951-d872f2087c98

2 files changed, 18 insertions, 7 deletions

diff --git a/base/os_compat_android.cc b/base/os_compat_android.cc
index d500656..e8b6e2f 100644
--- a/base/os_compat_android.cc
+++ b/base/os_compat_android.cc
@@ -4,6 +4,8 @@
 
 #include "base/os_compat_android.h"
 
+#include <time64.h>
+
 #include "base/stringprintf.h"
 
 // There is no futimes() avaiable in Bionic, so we provide our own
@@ -15,4 +17,16 @@ int futimes(int fd, const struct timeval tv[2]) {
   return utimes(fd_path.c_str(), tv);
 }
 
+// Android has only timegm64() and no timegm().
+// We replicate the behaviour of timegm() when the result overflows time_t.
+time_t timegm(struct tm* const t) {
+  // time_t is signed on Android.
+  static const time_t kTimeMax = ~(1 << (sizeof(time_t) * CHAR_BIT - 1));
+  static const time_t kTimeMin = (1 << (sizeof(time_t) * CHAR_BIT - 1));
+  time64_t result = timegm64(t);
+  if (result < kTimeMin || result > kTimeMax)
+    return -1;
+  return result;
+}
+
 }  // extern "C"
diff --git a/base/os_compat_android.h b/base/os_compat_android.h
index af6e167..e43319d 100644
--- a/base/os_compat_android.h
+++ b/base/os_compat_android.h
@@ -8,15 +8,17 @@
 
 #include <fcntl.h>
 #include <sys/types.h>
-#include <time64.h>
 #include <utime.h>
 
-// Not implemented in Bionic. See platform_file_android.cc.
+// Not implemented in Bionic.
 extern "C" int futimes(int fd, const struct timeval tv[2]);
 
 // The prototype of mkdtemp is missing.
 extern "C" char* mkdtemp(char* path);
 
+// Android has no timegm().
+extern "C" time_t timegm(struct tm* const t);
+
 // The lockf() function is not available on Android; we translate to flock().
 #define F_LOCK LOCK_EX
 #define F_ULOCK LOCK_UN
@@ -24,9 +26,4 @@ inline int lockf(int fd, int cmd, off_t ignored_len) {
   return flock(fd, cmd);
 }
 
-// Android has only timegm64() and no timegm().
-inline time_t timegm(struct tm* const tmp) {
-  return static_cast<time_t>(timegm64(tmp));
-}
-
 #endif  // BASE_OS_COMPAT_ANDROID_H_