use gmtime_r() instead of gmtime()

This avoids pulling in gmtime's static buffer:

function                                             old     new   delta
svlogd_main                                         1401    1412     +11
send_headers                                         668     678     +10
gmtime                                                21       -     -21
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 2/0 up/down: 21/-21)              Total: 0 bytes
   text	   data	    bss	    dec	    hex	filename
 920221	    555	   5804	 926580	  e2374	busybox_old
 920221	    555	   5740	 926516	  e2334	busybox_unstripped
                   ^^^^

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

3 files changed, 8 insertions, 3 deletions

diff --git a/networking/httpd.c b/networking/httpd.c
index 74196a4f1..9439e206c 100644
--- a/networking/httpd.c
+++ b/networking/httpd.c
@@ -1046,6 +1046,7 @@ static void send_headers(int responseNum)
         /* Fixed size 29-byte string. Example: Sun, 06 Nov 1994 08:49:37 GMT */
         char date_str[40]; /* using a bit larger buffer to paranoia reasons */
 
+        struct tm tm;
         const char *responseString = "";
         const char *infoString = NULL;
 #if ENABLE_FEATURE_HTTPD_ERROR_PAGES
@@ -1074,7 +1075,8 @@ static void send_headers(int responseNum)
          * always fit into those kbytes.
          */
 
-        strftime(date_str, sizeof(date_str), RFC1123FMT, gmtime(&timer));
+        strftime(date_str, sizeof(date_str), RFC1123FMT, gmtime_r(&timer, &tm));
+        /* ^^^ using gmtime_r() instead of gmtime() to not use static data */
         len = sprintf(iobuf,
                         "HTTP/1.0 %d %s\r\n"
                         "Content-type: %s\r\n"
@@ -1128,7 +1130,7 @@ static void send_headers(int responseNum)
 #endif
 
         if (file_size != -1) {    /* file */
-                strftime(date_str, sizeof(date_str), RFC1123FMT, gmtime(&last_mod));
+                strftime(date_str, sizeof(date_str), RFC1123FMT, gmtime_r(&last_mod, &tm));
 #if ENABLE_FEATURE_HTTPD_RANGES
                 if (responseNum == HTTP_PARTIAL_CONTENT) {
                         len += sprintf(iobuf + len,
diff --git a/runit/svlogd.c b/runit/svlogd.c
index 412290ca9..13de2570f 100644
--- a/runit/svlogd.c
+++ b/runit/svlogd.c
@@ -347,11 +347,13 @@ static unsigned pmatch(const char *p, const char *s, unsigned len)
 /* NUL terminated */
 static void fmt_time_human_30nul(char *s, char dt_delim)
 {
+        struct tm tm;
         struct tm *ptm;
         struct timeval tv;
 
         gettimeofday(&tv, NULL);
-        ptm = gmtime(&tv.tv_sec);
+        ptm = gmtime_r(&tv.tv_sec, &tm);
+        /* ^^^ using gmtime_r() instead of gmtime() to not use static data */
         sprintf(s, "%04u-%02u-%02u%c%02u:%02u:%02u.%06u000",
                 (unsigned)(1900 + ptm->tm_year),
                 (unsigned)(ptm->tm_mon + 1),
diff --git a/sysklogd/syslogd_and_logger.c b/sysklogd/syslogd_and_logger.c
index 9bba195d4..94d8273b6 100644
--- a/sysklogd/syslogd_and_logger.c
+++ b/sysklogd/syslogd_and_logger.c
@@ -53,6 +53,7 @@ typedef struct _code {
 static const CODE *const bb_prioritynames = prioritynames;
 static const CODE *const bb_facilitynames = facilitynames;
 
+
 #if ENABLE_SYSLOGD
 #include "syslogd.c"
 #endif