1/*-
2 * Copyright (c) 2007 Dag-Erling Co�dan Sm�rgrav
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer
10 * in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
16 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
17 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
18 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
21 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
|
29__FBSDID("$FreeBSD: head/lib/libutil/flopen.c 169449 2007-05-10 14:56:07Z des $");
|
| 29__FBSDID("$FreeBSD: head/lib/libutil/flopen.c 169450 2007-05-10 15:01:42Z des $"); |
30
|
| 31#include <sys/file.h> |
32#include <sys/stat.h>
33
34#include <errno.h>
35#include <fcntl.h>
36#include <stdarg.h>
|
| 37#include <unistd.h> |
38
|
39#include <libutil.h>
40 |
41int
42flopen(const char *path, int flags, ...)
43{
44 int fd, operation, serrno;
45 struct stat sb, fsb;
46 mode_t mode;
47
48#ifdef O_EXLOCK
49 flags &= ~O_EXLOCK;
50#endif
51
52 mode = 0;
53 if (flags & O_CREAT) {
54 va_list ap;
55
56 va_start(ap, flags);
57 mode = va_arg(ap, int); /* mode_t promoted to int */
58 va_end(ap);
59 }
60
61 operation = LOCK_EX;
62 if (flags & O_NONBLOCK)
63 operation |= LOCK_NB;
64
65 for (;;) {
66 if ((fd = open(path, flags, mode)) == -1)
67 /* non-existent or no access */
68 return (-1);
69 if (flock(fd, operation) == -1) {
70 /* unsupported or interrupted */
71 serrno = errno;
72 close(fd);
73 errno = serrno;
74 return (-1);
75 }
76 if (stat(path, &sb) == -1) {
77 /* disappeared from under our feet */
78 close(fd);
79 continue;
80 }
81 if (fstat(fd, &fsb) == -1) {
82 /* can't happen [tm] */
83 serrno = errno;
84 close(fd);
85 errno = serrno;
86 return (-1);
87 }
88 if (sb.st_dev != fsb.st_dev ||
89 sb.st_ino != fsb.st_ino) {
90 /* changed under our feet */
91 close(fd);
92 continue;
93 }
94 return (fd);
95 }
96}
|