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authorAdhemerval Zanella <adhemerval.zanella@linaro.com>2015-07-15 16:15:47 -0300
committerAdhemerval Zanella <adhemerval.zanella@linaro.com>2015-07-16 15:21:49 -0300
commit787813b14425c9c2e699a90e27eee1cfdfe73ec2 (patch)
tree8fb22cea093163f6706988781a5eb6012dd442e1 /libio
parentb42f8cad52ebfbfd43ebf6e42e606b489ffbd466 (diff)
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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.
Diffstat (limited to 'libio')
-rw-r--r--libio/fmemopen.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/libio/fmemopen.c b/libio/fmemopen.c
index e6e6a49f76..3ab3e8dac4 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);
     }