1 /* Licensed to the Apache Software Foundation (ASF) under one or more
2 * contributor license agreements. See the NOTICE file distributed with
3 * this work for additional information regarding copyright ownership.
4 * The ASF licenses this file to You under the Apache License, Version 2.0
5 * (the "License"); you may not use this file except in compliance with
6 * the License. You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 #include "apr_arch_file_io.h"
18
19 #if APR_HAVE_FCNTL_H
20 #include <fcntl.h>
21 #endif
22 #ifdef HAVE_SYS_FILE_H
23 #include <sys/file.h>
24 #endif
25
apr_file_lock(apr_file_t * thefile,int type)26 APR_DECLARE(apr_status_t) apr_file_lock(apr_file_t *thefile, int type)
27 {
28 int rc;
29
30 #if defined(HAVE_FCNTL_H)
31 {
32 struct flock l = { 0 };
33 int fc;
34
35 l.l_whence = SEEK_SET; /* lock from current point */
36 l.l_start = 0; /* begin lock at this offset */
37 l.l_len = 0; /* lock to end of file */
38 if ((type & APR_FLOCK_TYPEMASK) == APR_FLOCK_SHARED)
39 l.l_type = F_RDLCK;
40 else
41 l.l_type = F_WRLCK;
42
43 fc = (type & APR_FLOCK_NONBLOCK) ? F_SETLK : F_SETLKW;
44
45 /* keep trying if fcntl() gets interrupted (by a signal) */
46 while ((rc = fcntl(thefile->filedes, fc, &l)) < 0 && errno == EINTR)
47 continue;
48
49 if (rc == -1) {
50 /* on some Unix boxes (e.g., Tru64), we get EACCES instead
51 * of EAGAIN; we don't want APR_STATUS_IS_EAGAIN() matching EACCES
52 * since that breaks other things, so fix up the retcode here
53 */
54 if (errno == EACCES) {
55 return EAGAIN;
56 }
57 return errno;
58 }
59 }
60 #elif defined(HAVE_SYS_FILE_H)
61 {
62 int ltype;
63
64 if ((type & APR_FLOCK_TYPEMASK) == APR_FLOCK_SHARED)
65 ltype = LOCK_SH;
66 else
67 ltype = LOCK_EX;
68 if ((type & APR_FLOCK_NONBLOCK) != 0)
69 ltype |= LOCK_NB;
70
71 /* keep trying if flock() gets interrupted (by a signal) */
72 while ((rc = flock(thefile->filedes, ltype)) < 0 && errno == EINTR)
73 continue;
74
75 if (rc == -1)
76 return errno;
77 }
78 #else
79 #error No file locking mechanism is available.
80 #endif
81
82 return APR_SUCCESS;
83 }
84
apr_file_unlock(apr_file_t * thefile)85 APR_DECLARE(apr_status_t) apr_file_unlock(apr_file_t *thefile)
86 {
87 int rc;
88
89 #if defined(HAVE_FCNTL_H)
90 {
91 struct flock l = { 0 };
92
93 l.l_whence = SEEK_SET; /* lock from current point */
94 l.l_start = 0; /* begin lock at this offset */
95 l.l_len = 0; /* lock to end of file */
96 l.l_type = F_UNLCK;
97
98 /* keep trying if fcntl() gets interrupted (by a signal) */
99 while ((rc = fcntl(thefile->filedes, F_SETLKW, &l)) < 0
100 && errno == EINTR)
101 continue;
102
103 if (rc == -1)
104 return errno;
105 }
106 #elif defined(HAVE_SYS_FILE_H)
107 {
108 /* keep trying if flock() gets interrupted (by a signal) */
109 while ((rc = flock(thefile->filedes, LOCK_UN)) < 0 && errno == EINTR)
110 continue;
111
112 if (rc == -1)
113 return errno;
114 }
115 #else
116 #error No file locking mechanism is available.
117 #endif
118
119 return APR_SUCCESS;
120 }
121