From: Adhemerval Zanella <adhemerval.zanella@linaro.com>
Date: Wed, 15 Jul 2015 19:15:47 +0000 (-0300)
Subject: libio: Fix fmemopen 'w' mode with provided buffer
X-Git-Tag: glibc-2.22~54
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=787813b14425c9c2e699a90e27eee1cfdfe73ec2;p=thirdparty%2Fglibc.git

libio: Fix fmemopen 'w' mode with provided buffer

If 'w' mode is used with a provided buffer the fmemopen will try to find
the first null byte to set as maximum internal stream size.  It should be
done only for append mode ('a').

Kudos for Stefan Liebler for finding this error on s390-32.

	* libio/fmemopen.c (__fmemopen): Fix 'w' openmode with provided
	buffer.
	* stdio-common/tst-fmemopen2.c (do_test_with_buffer): Fix typo and
	fail output information.
---

diff --git a/ChangeLog b/ChangeLog
index 809fe1807a9..17f33774deb 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+2015-07-16  Adhemerval Zanella  <adhemerval.zanella@linaro.org>
+
+	* libio/fmemopen.c (__fmemopen): Fix 'w' openmode with provided
+	buffer.
+	* stdio-common/tst-fmemopen2.c (do_test_with_buffer): Fix typo and
+	fail output information.
+
 2015-07-16  Rajalakshmi Srinivasaraghavan  <raji@linux.vnet.ibm.com>
 
 	* sysdeps/powerpc/powerpc64/multiarch/Makefile: Add strstr-power7
diff --git a/libio/fmemopen.c b/libio/fmemopen.c
index e6e6a49f76d..3ab3e8dac48 100644
--- a/libio/fmemopen.c
+++ b/libio/fmemopen.c
@@ -150,7 +150,7 @@ __fmemopen (void *buf, size_t len, const char *mode)
   cookie_io_functions_t iof;
   fmemopen_cookie_t *c;
 
-  c = (fmemopen_cookie_t *) malloc (sizeof (fmemopen_cookie_t));
+  c = (fmemopen_cookie_t *) calloc (sizeof (fmemopen_cookie_t), 1);
   if (c == NULL)
     return NULL;
 
@@ -165,7 +165,6 @@ __fmemopen (void *buf, size_t len, const char *mode)
 	  return NULL;
 	}
       c->buffer[0] = '\0';
-      c->maxpos = 0;
     }
   else
     {
@@ -182,7 +181,8 @@ __fmemopen (void *buf, size_t len, const char *mode)
       if (mode[0] == 'w' && mode[1] == '+')
 	c->buffer[0] = '\0';
 
-      c->maxpos = strnlen (c->buffer, len);
+      if (mode[0] == 'a')
+        c->maxpos = strnlen (c->buffer, len);
     }
 
 
diff --git a/stdio-common/tst-fmemopen2.c b/stdio-common/tst-fmemopen2.c
index 16dd3ad73dc..a2c05c12df3 100644
--- a/stdio-common/tst-fmemopen2.c
+++ b/stdio-common/tst-fmemopen2.c
@@ -34,7 +34,7 @@ do_test_with_buffer (void)
   FILE *fp = fmemopen (buf, nbuf, "w");
   if (fp == NULL)
     {
-      printf ("FAIL: fmemopen failedi (%s)\n", __FUNCTION__);
+      printf ("FAIL: fmemopen failed (%s)\n", __FUNCTION__);
       return 1;
     }
 
@@ -69,7 +69,7 @@ do_test_with_buffer (void)
   if (o != nstr)
     {
       printf ("FAIL: third ftello returned %jd, expected %zu\n",
-	      (intmax_t)o, nbuf);
+	      (intmax_t)o, nstr);
       result = 1;
     }