[src/trunk]: src/lib/libc/gen When updating wtmpx, if the write fails make su...

[matt <matt%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/024c8a31ad78
branches:  trunk
changeset: 550937:024c8a31ad78
user:      matt <matt%NetBSD.org@localhost>
date:      Mon Aug 25 23:09:37 2003 +0000

description:
When updating wtmpx, if the write fails make sure to close the file (to
release the lock held on it).  Use O_SHLOCK when adding just one record
since O_APPEND will enforce the atomicity that is required.

diffstat:

 lib/libc/gen/utmpx.c |  17 ++++++++++++-----
 1 files changed, 12 insertions(+), 5 deletions(-)

diffs (54 lines):

diff -r db776f92c69b -r 024c8a31ad78 lib/libc/gen/utmpx.c
--- a/lib/libc/gen/utmpx.c      Mon Aug 25 23:00:23 2003 +0000
+++ b/lib/libc/gen/utmpx.c      Mon Aug 25 23:09:37 2003 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: utmpx.c,v 1.18 2003/08/24 15:14:18 kleink Exp $         */
+/*     $NetBSD: utmpx.c,v 1.19 2003/08/25 23:09:37 matt Exp $   */
 
 /*-
  * Copyright (c) 2002 The NetBSD Foundation, Inc.
@@ -38,7 +38,7 @@
 #include <sys/cdefs.h>
 
 #if defined(LIBC_SCCS) && !defined(lint)
-__RCSID("$NetBSD: utmpx.c,v 1.18 2003/08/24 15:14:18 kleink Exp $");
+__RCSID("$NetBSD: utmpx.c,v 1.19 2003/08/25 23:09:37 matt Exp $");
 #endif /* LIBC_SCCS and not lint */
 
 #include "namespace.h"
@@ -308,11 +308,12 @@
 updwtmpx(const char *file, const struct utmpx *utx)
 {
        int fd;
+       int saved_errno;
 
        _DIAGASSERT(file != NULL);
        _DIAGASSERT(utx != NULL);
 
-       fd = open(file, O_WRONLY|O_APPEND|O_EXLOCK);
+       fd = open(file, O_WRONLY|O_APPEND|O_SHLOCK);
 
        if (fd == -1) {
                if ((fd = open(file, O_CREAT|O_WRONLY|O_EXLOCK, 0644)) == -1)
@@ -321,13 +322,19 @@
                ut.ut_type = SIGNATURE;
                (void)memcpy(ut.ut_user, vers, sizeof(vers));
                if (write(fd, &ut, sizeof(ut)) == -1)
-                       return -1;
+                       goto failed;
        }
        if (write(fd, utx, sizeof(*utx)) == -1)
-               return -1;
+               goto failed;
        if (close(fd) == -1)
                return -1;
        return 0;
+
+  failed:
+       saved_errno = errno;
+       (void) close(fd);
+       errno = saved_errno;
+       return -1;
 }