Use gmtime_r instead of gmtime and localtime_r instead of localtime

gmtime isn't thread safe in general. In msvcrt (which lacks gmtime_r),
the buffer used by gmtime is thread specific though.

One call to localtime is left in avconv_opt.c, where thread safety
shouldn't matter (instead of making avconv depend on the libavutil
internal header).
Signed-off-by: Martin Storsjö <martin@martin.st>

libavformat/mov.c

@@ -34,6 +34,7 @@
 #include "libavutil/intreadwrite.h"
 #include "libavutil/intfloat.h"
 #include "libavutil/mathematics.h"
+#include "libavutil/time_internal.h"
 #include "libavutil/avstring.h"
 #include "libavutil/dict.h"
 #include "libavcodec/ac3tab.h"
@@ -739,9 +740,9 @@ static void mov_metadata_creation_time(AVDictionary **metadata, time_t time)
 {
     char buffer[32];
     if (time) {
-        struct tm *ptm;
+        struct tm *ptm, tmbuf;
         time -= 2082844800;  /* seconds between 1904-01-01 and Epoch */
-        ptm = gmtime(&time);
+        ptm = gmtime_r(&time, &tmbuf);
         if (!ptm) return;
         if (strftime(buffer, sizeof(buffer), "%Y-%m-%d %H:%M:%S", ptm))
             av_dict_set(metadata, "creation_time", buffer, 0);

libavformat/mxfenc.c

@@ -35,6 +35,7 @@
 #include <time.h>
 
 #include "libavutil/random_seed.h"
+#include "libavutil/time_internal.h"
 #include "libavcodec/bytestream.h"
 #include "audiointerleave.h"
 #include "avformat.h"
@@ -1386,7 +1387,8 @@ static int mxf_parse_mpeg2_frame(AVFormatContext *s, AVStream *st,
 
 static uint64_t mxf_parse_timestamp(time_t timestamp)
 {
-    struct tm *time = gmtime(&timestamp);
+    struct tm tmbuf;
+    struct tm *time = gmtime_r(&timestamp, &tmbuf);
     if (!time)
         return 0;
     return (uint64_t)(time->tm_year+1900) << 48 |

libavformat/wtv.c

@@ -31,6 +31,7 @@
 #include "libavutil/intreadwrite.h"
 #include "libavutil/intfloat.h"
 #include "libavutil/dict.h"
+#include "libavutil/time_internal.h"
 #include "avformat.h"
 #include "internal.h"
 #include "riff.h"
@@ -428,7 +429,8 @@ static int read_probe(AVProbeData *p)
 static void filetime_to_iso8601(char *buf, int buf_size, int64_t value)
 {
     time_t t = (value / 10000000LL) - 11644473600LL;
-    struct tm *tm = gmtime(&t);
+    struct tm tmbuf;
+    struct tm *tm = gmtime_r(&t, &tmbuf);
     if (tm) {
         if (!strftime(buf, buf_size, "%Y-%m-%d %H:%M:%S", tm))
             buf[0] = '\0';
@@ -442,7 +444,8 @@ static void filetime_to_iso8601(char *buf, int buf_size, int64_t value)
 static void crazytime_to_iso8601(char *buf, int buf_size, int64_t value)
 {
     time_t t = (value / 10000000LL) - 719162LL*86400LL;
-    struct tm *tm = gmtime(&t);
+    struct tm tmbuf;
+    struct tm *tm = gmtime_r(&t, &tmbuf);
     if (tm) {
         if (!strftime(buf, buf_size, "%Y-%m-%d %H:%M:%S", tm))
             buf[0] = '\0';
@@ -456,7 +459,8 @@ static void crazytime_to_iso8601(char *buf, int buf_size, int64_t value)
 static void oledate_to_iso8601(char *buf, int buf_size, int64_t value)
 {
     time_t t = 631112400LL + 86400*av_int2double(value);
-    struct tm *tm = gmtime(&t);
+    struct tm tmbuf;
+    struct tm *tm = gmtime_r(&t, &tmbuf);
     if (tm) {
         if (!strftime(buf, buf_size, "%Y-%m-%d %H:%M:%S", tm))
             buf[0] = '\0';

libavutil/parseutils.c

@@ -29,6 +29,7 @@
 #include "eval.h"
 #include "log.h"
 #include "random_seed.h"
+#include "time_internal.h"
 #include "parseutils.h"
 
 typedef struct {
@@ -483,7 +484,7 @@ int av_parse_time(int64_t *timeval, const char *timestr, int duration)
 {
     const char *p;
     int64_t t;
-    struct tm dt = { 0 };
+    struct tm dt = { 0 }, tmbuf;
     int i;
     static const char * const date_fmt[] = {
         "%Y-%m-%d",
@@ -527,9 +528,9 @@ int av_parse_time(int64_t *timeval, const char *timestr, int duration)
          * current year-month-day time */
         if (!q) {
             if (is_utc) {
-                dt = *gmtime(&now);
+                dt = *gmtime_r(&now, &tmbuf);
             } else {
-                dt = *localtime(&now);
+                dt = *localtime_r(&now, &tmbuf);
             }
             dt.tm_hour = dt.tm_min = dt.tm_sec = 0;
         } else {