Libc-1439.100.3.tar.gz

[apple/libc.git] / stdio / FreeBSD / fwrite.c

diff --git a/stdio/FreeBSD/fwrite.c b/stdio/FreeBSD/fwrite.c
index 27b660e8ca22b4499d872d46e45f4ee5cf41f509..09eae8374dd6520429b3b2c04c39e7b78690222f 100644 (file)
--- a/stdio/FreeBSD/fwrite.c
+++ b/stdio/FreeBSD/fwrite.c
@@ -13,10 +13,6 @@
  * 2. Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in the
  *    documentation and/or other materials provided with the distribution.
- * 3. All advertising materials mentioning features or use of this software
- *    must display the following acknowledgement:
- *     This product includes software developed by the University of
- *     California, Berkeley and its contributors.
  * 4. Neither the name of the University nor the names of its contributors
  *    may be used to endorse or promote products derived from this software
  *    without specific prior written permission.
@@ -38,7 +34,7 @@
 static char sccsid[] = "@(#)fwrite.c   8.1 (Berkeley) 6/4/93";
 #endif /* LIBC_SCCS and not lint */
 #include <sys/cdefs.h>
-__FBSDID("$FreeBSD: src/lib/libc/stdio/fwrite.c,v 1.11 2002/10/12 16:13:41 mike Exp $");
+__FBSDID("$FreeBSD: src/lib/libc/stdio/fwrite.c,v 1.13 2009/07/12 13:09:43 ed Exp $");
 
 #include "namespace.h"
 #include <stdio.h>
@@ -47,6 +43,13 @@ __FBSDID("$FreeBSD: src/lib/libc/stdio/fwrite.c,v 1.11 2002/10/12 16:13:41 mike
 #include "fvwrite.h"
 #include "libc_private.h"
 
+/*
+ * The maximum amount to write to avoid integer overflow (especially for
+ * uio_resid in struct __suio).  INT_MAX is odd, so it make sense to make it
+ * even.  We subtract (BUFSIZ - 1) to get a whole number of BUFSIZ chunks.
+ */
+#define MAXWRITE       (INT_MAX - (BUFSIZ - 1))
+
 /*
  * Write `count' objects (each size `size') from memory to the given file.
  * Return the number of whole objects written.
@@ -57,24 +60,40 @@ fwrite(buf, size, count, fp)
        size_t size, count;
        FILE * __restrict fp;
 {
-       size_t n;
+       size_t n, resid;
        struct __suio uio;
        struct __siov iov;
+       int s;
 
-       iov.iov_base = (void *)buf;
-       uio.uio_resid = iov.iov_len = n = count * size;
+       /*
+        * ANSI and SUSv2 require a return value of 0 if size or count are 0.
+        */
+       n = count * size;
+#if __DARWIN_UNIX03
+       if (n == 0)
+               return (0);
+#endif
        uio.uio_iov = &iov;
        uio.uio_iovcnt = 1;
 
        FLOCKFILE(fp);
        ORIENT(fp, -1);
-       /*
-        * The usual case is success (__sfvwrite returns 0);
-        * skip the divide if this happens, since divides are
-        * generally slow and since this occurs whenever size==0.
-        */
-       if (__sfvwrite(fp, &uio) != 0)
-           count = (n - uio.uio_resid) / size;
+
+       for (resid = n; resid > 0; buf += s, resid -= s) {
+               s = resid > INT_MAX ? MAXWRITE : (int)resid;
+               iov.iov_base = (void *)buf;
+               uio.uio_resid = iov.iov_len = s;
+
+               /*
+                * The usual case is success (__sfvwrite returns 0);
+                * skip the divide if this happens, since divides are
+                * generally slow and since this occurs whenever size==0.
+                */
+               if (__sfvwrite(fp, &uio) != 0) {
+                       count = (n - resid + s - uio.uio_resid) / size;
+                       break;
+               }
+       }
        FUNLOCKFILE(fp);
        return (count);
 }