zygote: Redirect 64-bit libc localtime and localtime_r routines.

content/zygote/zygote_main_linux.cc

Index: content/zygote/zygote_main_linux.cc
diff --git a/content/zygote/zygote_main_linux.cc b/content/zygote/zygote_main_linux.cc
index 21f54d8dfa9318328c7874b398c5da6dfa021cf9..36b1a8db2239b17518282cfe047c4bb546b7b7e3 100644
--- a/content/zygote/zygote_main_linux.cc
+++ b/content/zygote/zygote_main_linux.cc
@@ -173,7 +173,9 @@ typedef int (*Xstat64Function)(int version, const char *path,
 
 static pthread_once_t g_libc_localtime_funcs_guard = PTHREAD_ONCE_INIT;
 static LocaltimeFunction g_libc_localtime;
+static LocaltimeFunction g_libc_localtime64;
 static LocaltimeRFunction g_libc_localtime_r;
+static LocaltimeRFunction g_libc_localtime64_r;
 
 static pthread_once_t g_libc_file_io_funcs_guard = PTHREAD_ONCE_INIT;
 static FopenFunction g_libc_fopen;
@@ -184,8 +186,12 @@ static Xstat64Function g_libc_xstat64;
 static void InitLibcLocaltimeFunctions() {
   g_libc_localtime = reinterpret_cast<LocaltimeFunction>(
       dlsym(RTLD_NEXT, "localtime"));
+  g_libc_localtime64 = reinterpret_cast<LocaltimeFunction>(
+      dlsym(RTLD_NEXT, "localtime64"));
   g_libc_localtime_r = reinterpret_cast<LocaltimeRFunction>(
       dlsym(RTLD_NEXT, "localtime_r"));
+  g_libc_localtime64_r = reinterpret_cast<LocaltimeRFunction>(
+      dlsym(RTLD_NEXT, "localtime64_r"));
 
   if (!g_libc_localtime || !g_libc_localtime_r) {

[Jorge Lucangeli Obes, 2012/05/16 02:59:45]

Shouldn't you add checks for the *64 versions of the functions, since you're
calling them in the new code? Are we sure the bug below does not apply in this
case?

[hshi1, 2012/05/16 17:36:16]

Done.

     // http://code.google.com/p/chromium/issues/detail?id=16800
@@ -205,7 +211,11 @@ static void InitLibcLocaltimeFunctions() {
     g_libc_localtime_r = gmtime_r;
 }
 
-struct tm* localtime(const time_t* timep) {
+__attribute__ ((__visibility__("default")))

[Jorge Lucangeli Obes, 2012/05/16 02:59:45]

Why do we need the visibility annotations?

[hshi1, 2012/05/16 03:04:09]

This is a copy&paste based on the fopen/fopen64 code. I'm not sure if it is
really needed or not...

On 2012/05/16 02:59:45, Jorge Lucangeli Obes wrote:

[hshi1, 2012/05/16 17:36:16]

It appears to be useless. I would assume that visiblity is "default" by default!

On 2012/05/16 03:04:09, hshi1 wrote:

[hshi1, 2012/05/16 17:44:57]

Sorry, I take this back. It appears that the visibility setting is indeed
necessary. Without this line I will get a system hang at boot time. I am guess
that is why this is used in the tricks for fopen and fopen64 below.

+struct tm* localtime_override(const time_t* timep) __asm__ ("localtime");
+
+__attribute__ ((__visibility__("default")))
+struct tm* localtime_override(const time_t* timep) {
   if (g_am_zygote_or_renderer) {
     static struct tm time_struct;
     static char timezone_string[64];
@@ -219,7 +229,30 @@ struct tm* localtime(const time_t* timep) {
   }
 }
 
-struct tm* localtime_r(const time_t* timep, struct tm* result) {
+__attribute__ ((__visibility__("default")))
+struct tm* localtime64_override(const time_t* timep) __asm__ ("localtime64");
+
+__attribute__ ((__visibility__("default")))
+struct tm* localtime64_override(const time_t* timep) {
+  if (g_am_zygote_or_renderer) {
+    static struct tm time_struct;
+    static char timezone_string[64];
+    ProxyLocaltimeCallToBrowser(*timep, &time_struct, timezone_string,
+                                sizeof(timezone_string));
+    return &time_struct;
+  } else {
+    CHECK_EQ(0, pthread_once(&g_libc_localtime_funcs_guard,
+                             InitLibcLocaltimeFunctions));
+    return g_libc_localtime64(timep);
+  }
+}
+
+__attribute__ ((__visibility__("default")))
+struct tm* localtime_r_override(const time_t* timep,
+                                struct tm* result) __asm__ ("localtime_r");
+
+__attribute__ ((__visibility__("default")))
+struct tm* localtime_r_override(const time_t* timep, struct tm* result) {
   if (g_am_zygote_or_renderer) {
     ProxyLocaltimeCallToBrowser(*timep, result, NULL, 0);
     return result;
@@ -230,6 +263,22 @@ struct tm* localtime_r(const time_t* timep, struct tm* result) {
   }
 }
 
+__attribute__ ((__visibility__("default")))
+struct tm* localtime64_r_override(const time_t* timep,
+                                  struct tm* result) __asm__ ("localtime64_r");
+
+__attribute__ ((__visibility__("default")))
+struct tm* localtime64_r_override(const time_t* timep, struct tm* result) {
+  if (g_am_zygote_or_renderer) {
+    ProxyLocaltimeCallToBrowser(*timep, result, NULL, 0);
+    return result;
+  } else {
+    CHECK_EQ(0, pthread_once(&g_libc_localtime_funcs_guard,
+                             InitLibcLocaltimeFunctions));
+    return g_libc_localtime64_r(timep, result);
+  }
+}
+
 // TODO(sergeyu): Currently this code doesn't work properly under ASAN
 // - it crashes content_unittests. Make sure it works properly and
 // enable it here. http://crbug.com/123263