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readv update for POSIX.1-2001

POSIX.1-2001 requires that readv fails with EINVAL if the total buffer
length overflows the range of ssize_t.

Andreas.

2002-01-31  Andreas Schwab  <schwab@suse.de>

	* sysdeps/posix/readv.c: Check for ssize_t overflow.

--- sysdeps/posix/readv.c.~1.8.~	Mon Jul 16 10:44:44 2001
+++ sysdeps/posix/readv.c	Thu Jan 31 10:36:01 2002
@@ -19,6 +19,7 @@
 #include <stdlib.h>
 #include <unistd.h>
 #include <string.h>
+#include <limits.h>
 #include <sys/uio.h>
 
 /* Read data from file descriptor FD, and put the result in the
@@ -40,7 +41,15 @@
   /* Find the total number of bytes to be read.  */
   bytes = 0;
   for (i = 0; i < count; ++i)
-    bytes += vector[i].iov_len;
+    {
+      /* Check for ssize_t overflow.  */
+      if (SSIZE_MAX - bytes < vector[i].iov_len)
+	{
+	  errno = EINVAL;
+	  return -1;
+	}
+      bytes += vector[i].iov_len;
+    }
 
   /* Allocate a temporary buffer to hold the data.  */
   buffer = (char *) __alloca (bytes);

-- 
Andreas Schwab, SuSE Labs, schwab@suse.de
SuSE GmbH, Deutschherrnstr. 15-19, D-90429 Nürnberg
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