Module Name: src
Committed By: christos
Date: Fri Jul 16 12:34:10 UTC 2021
Modified Files:
src/lib/libc/stdio: fvwrite.c
Log Message:
When fflush fails, adjust pointers and the io vectors. From RVP. Fixes
core-dump at cvs(1) exit(3).
To generate a diff of this commit:
cvs rdiff -u -r1.27 -r1.28 src/lib/libc/stdio/fvwrite.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/lib/libc/stdio/fvwrite.c
diff -u src/lib/libc/stdio/fvwrite.c:1.27 src/lib/libc/stdio/fvwrite.c:1.28
--- src/lib/libc/stdio/fvwrite.c:1.27 Thu Jul 8 05:06:51 2021
+++ src/lib/libc/stdio/fvwrite.c Fri Jul 16 08:34:10 2021
@@ -1,4 +1,4 @@
-/* $NetBSD: fvwrite.c,v 1.27 2021/07/08 09:06:51 christos Exp $ */
+/* $NetBSD: fvwrite.c,v 1.28 2021/07/16 12:34:10 christos Exp $ */
/*-
* Copyright (c) 1990, 1993
@@ -37,7 +37,7 @@
#if 0
static char sccsid[] = "@(#)fvwrite.c 8.1 (Berkeley) 6/4/93";
#else
-__RCSID("$NetBSD: fvwrite.c,v 1.27 2021/07/08 09:06:51 christos Exp $");
+__RCSID("$NetBSD: fvwrite.c,v 1.28 2021/07/16 12:34:10 christos Exp $");
#endif
#endif /* LIBC_SCCS and not lint */
@@ -51,6 +51,40 @@ __RCSID("$NetBSD: fvwrite.c,v 1.27 2021/
#include "local.h"
#include "fvwrite.h"
+static int
+flush_adj(FILE *fp, struct __suio *uio, struct __siov *iov, ssize_t w)
+{
+ int rc;
+
+ _DIAGASSERT(w >= 0);
+ _DIAGASSERT(fp->_w >= 0);
+
+ if ((rc = fflush(fp)) == 0)
+ return 0;
+
+ /*
+ * If we have to return without writing the whole buffer,
+ * adjust for how much fflush() has written for us.
+ * `w' is the amt. of new user data just copied into our
+ * internal buffer in _this_ fwrite() call.
+ */
+ if (fp->_w < w) {
+ /* some new data was also written */
+ ssize_t i = w - fp->_w;
+
+ /* adjust amt. written */
+ uio->uio_resid -= i;
+ iov->iov_len -= i;
+ } else {
+ /* only old stuff was written */
+
+ /* adjust _p and _w so user can retry */
+ fp->_p -= w;
+ fp->_w += w;
+ }
+ return rc;
+}
+
/*
* Write some memory regions. Return zero on success, EOF on error.
*
@@ -102,10 +136,8 @@ __sfvwrite(FILE *fp, struct __suio *uio)
if (w <= 0) \
goto err
#define FLUSH(nw) \
- if (fflush(fp)) { \
- fp->_p -= nw; /* rewind unwritten */ \
- goto err; \
- }
+ if (flush_adj(fp, uio, iov - 1, nw)) \
+ goto err
if (fp->_flags & __SNBF) {
/*
