[PATCH 2.0][BZ #15670] Replace alloca in __tzfile_read by malloc.

[Ondřej Bílka]

On Mon, Oct 14, 2013 at 08:24:09PM +0200, Ondřej Bílka wrote:
> > if you're going to switch to malloc, then it seems like using asprintf would 
> > be simpler:
> > 	if (asprintf (&new, "%s/%s", tzdir, file))
> > 		goto ret_free_transitions;
> 
> ti would,

A asprintf simplifies code a bit as a size calculations are now
redundant.

	[BZ #15670]
	* time/tzfile.c (__tzfile_read): Replace alloca with malloc.


diff --git a/time/tzfile.c b/time/tzfile.c
index 9dd5130..6048d41 100644
--- a/time/tzfile.c
+++ b/time/tzfile.c
@@ -114,6 +114,7 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
   int was_using_tzfile = __use_tzfile;
   int trans_width = 4;
   size_t tzspec_len;
+  char *new = NULL;
 
   if (sizeof (time_t) != 4 && sizeof (time_t) != 8)
     abort ();
@@ -145,22 +146,12 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
   if (*file != '/')
     {
       const char *tzdir;
-      unsigned int len, tzdir_len;
-      char *new, *tmp;
 
       tzdir = getenv ("TZDIR");
       if (tzdir == NULL || *tzdir == '\0')
-	{
-	  tzdir = default_tzdir;
-	  tzdir_len = sizeof (default_tzdir) - 1;
-	}
-      else
-	tzdir_len = strlen (tzdir);
-      len = strlen (file) + 1;
-      new = (char *) __alloca (tzdir_len + 1 + len);
-      tmp = __mempcpy (new, tzdir, tzdir_len);
-      *tmp++ = '/';
-      memcpy (tmp, file, len);
+	tzdir = default_tzdir;
+      if (__asprintf (&new, "%s/%s", tzdir, file) == -1)
+	goto ret_free_transitions;
       file = new;
     }
 
@@ -173,6 +164,7 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
     {
       /* Nothing to do.  */
       __use_tzfile = 1;
+      free (new);
       return;
     }
 
@@ -528,11 +520,13 @@ __tzfile_read (const char *file, size_t extra, char **extrap)
   __timezone = -rule_stdoff;
 
   __use_tzfile = 1;
+  free (new);
   return;
 
  lose:
   fclose (f);
  ret_free_transitions:
+  free (new);
   free ((void *) transitions);
   transitions = NULL;
 }