[binutils-gdb] Use ctime_r and localtime_r for threadsafety

[binutils-gdb] Use ctime_r and localtime_r for threadsafety

[Christian Biesinger]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=53fea9c7e6d4993088016a16be56098fd819cebc

commit 53fea9c7e6d4993088016a16be56098fd819cebc
Author: Christian Biesinger <cbiesinger@google.com>
Date:   Thu Oct 31 16:02:41 2019 -0500

    Use ctime_r and localtime_r for threadsafety
    
    To make these calls threadsafe. localtime_r is provided by gnulib if
    necessary, and for ctime_r we can just use it because it is in a linux-
    specific file.
    
    gdb/ChangeLog:
    
    2019-11-15  Christian Biesinger  <cbiesinger@google.com>
    
    	* maint.c (scoped_command_stats::print_time): Use localtime_r
    	instead of localtime (provided through gnulib if necessary).
    	* nat/linux-osdata.c (time_from_time_t): Use ctime_r instead
    	of ctime.
    
    Change-Id: I329bbdc39d5b576f51859ba00f1617e024c30cbd

Diff:
---
 gdb/ChangeLog          | 7 +++++++
 gdb/maint.c            | 5 +++--
 gdb/nat/linux-osdata.c | 6 +++++-
 3 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index f31552b..f727aa4 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,5 +1,12 @@
 2019-11-15  Christian Biesinger  <cbiesinger@google.com>
 
+	* maint.c (scoped_command_stats::print_time): Use localtime_r
+	instead of localtime (provided through gnulib if necessary).
+	* nat/linux-osdata.c (time_from_time_t): Use ctime_r instead
+	of ctime.
+
+2019-11-15  Christian Biesinger  <cbiesinger@google.com>
+
 	* gdbsupport/common-defs.h: Include time.h before pathmax.h to
 	avoid compile errors.
 
diff --git a/gdb/maint.c b/gdb/maint.c
index ec9f4ab..a253584 100644
--- a/gdb/maint.c
+++ b/gdb/maint.c
@@ -1039,10 +1039,11 @@ scoped_command_stats::print_time (const char *msg)
   auto millis = ticks % 1000;
 
   std::time_t as_time = system_clock::to_time_t (now);
-  struct tm *tm = localtime (&as_time);
+  struct tm tm;
+  localtime_r (&as_time, &tm);
 
   char out[100];
-  strftime (out, sizeof (out), "%F %H:%M:%S", tm);
+  strftime (out, sizeof (out), "%F %H:%M:%S", &tm);
 
   printf_unfiltered ("%s.%03d - %s\n", out, (int) millis, msg);
 }
diff --git a/gdb/nat/linux-osdata.c b/gdb/nat/linux-osdata.c
index ca6acd3..d82c062 100644
--- a/gdb/nat/linux-osdata.c
+++ b/gdb/nat/linux-osdata.c
@@ -916,7 +916,11 @@ time_from_time_t (char *time, int maxlen, TIME_T seconds)
     {
       time_t t = (time_t) seconds;
 
-      strncpy (time, ctime (&t), maxlen);
+      /* Per the ctime_r manpage, this buffer needs to be at least 26
+         characters long.  */
+      char buf[30];
+      const char *time_str = ctime_r (&t, buf);
+      strncpy (time, time_str, maxlen);
       time[maxlen - 1] = '\0';
     }
 }