From: Bruno Haible <bruno@clisp.org>
Date: Sat, 3 Nov 2007 14:22:52 +0000 (+0100)
Subject: Fix detection of overflow: don't assume that snprintf is C99 compliant.
X-Git-Tag: v0.1~8011
X-Git-Url: http://erislabs.org.uk/gitweb/?a=commitdiff_plain;h=6c48d0159096088da3d62b4dce62838bc3f8607c;p=gnulib.git

Fix detection of overflow: don't assume that snprintf is C99 compliant.
---

diff --git a/ChangeLog b/ChangeLog
index 15cd4c705..6c965e410 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,11 @@
 2007-11-03  Bruno Haible  <bruno@clisp.org>
 
+	* lib/vasnprintf.c (VASNPRINTF): Don't assume that snprintf's return
+	value is C99 compliant.
+	Needed for OSF/1 5.1.
+
+2007-11-03  Bruno Haible  <bruno@clisp.org>
+
 	Fix out-of-memory handling of vasnprintf.
 	* lib/printf-parse.c: Include <errno.h>.
 	(PRINTF_PARSE): When failing, set errno to EINVAL or ENOMEM.
diff --git a/lib/vasnprintf.c b/lib/vasnprintf.c
index f081e3ade..6b4d6c6a5 100644
--- a/lib/vasnprintf.c
+++ b/lib/vasnprintf.c
@@ -3658,8 +3658,12 @@ VASNPRINTF (DCHAR_T *resultbuf, size_t *lengthp,
 		      }
 
 #if USE_SNPRINTF
-		    /* Handle overflow of the allocated buffer.  */
-		    if (count >= maxlen)
+		    /* Handle overflow of the allocated buffer.
+		       If such an overflow occurs, a C99 compliant snprintf()
+		       returns a count >= maxlen.  However, a non-compliant
+		       snprintf() function returns only count = maxlen - 1.  To
+		       cover both cases, test whether count >= maxlen - 1.  */
+		    if ((unsigned int) count + 1 >= maxlen)
 		      {
 			/* If maxlen already has attained its allowed maximum,
 			   allocating more memory will not increase maxlen.