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_flock_stub.c (71579) _flock_stub.c (72373)
1/*
2 * Copyright (c) 1998 John Birrell <jb@cimlogic.com.au>.
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

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24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
1/*
2 * Copyright (c) 1998 John Birrell <jb@cimlogic.com.au>.
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

--- 15 unchanged lines hidden (view full) ---

24 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
25 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
26 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
27 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
28 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
29 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
30 * SUCH DAMAGE.
31 *
32 * $FreeBSD: head/lib/libc/stdio/_flock_stub.c 71579 2001-01-24 13:01:12Z deischen $
32 * $FreeBSD: head/lib/libc/stdio/_flock_stub.c 72373 2001-02-11 22:06:43Z deischen $
33 *
34 */
35
33 *
34 */
35
36/*
37 * POSIX stdio FILE locking functions. These assume that the locking
38 * is only required at FILE structure level, not at file descriptor
39 * level too.
40 *
41 */
42
43#include "namespace.h"
36#include <stdio.h>
44#include <stdio.h>
45#include <stdlib.h>
46#include <string.h>
47#include <pthread.h>
48#include "un-namespace.h"
37
38/*
49
50/*
39 * Declare weak references in case the application is not linked
40 * with libpthread.
51 * Weak symbols for externally visible functions in this file:
41 */
52 */
42#pragma weak flockfile=_flockfile_stub
43#pragma weak _flockfile=_flockfile_stub
44#pragma weak _flockfile_debug=_flockfile_debug_stub
45#pragma weak ftrylockfile=_ftrylockfile_stub
46#pragma weak _ftrylockfile=_ftrylockfile_stub
47#pragma weak funlockfile=_funlockfile_stub
48#pragma weak _funlockfile=_funlockfile_stub
53#pragma weak flockfile=_flockfile
54#pragma weak _flockfile_debug=_flockfile_debug_stub
55#pragma weak ftrylockfile=_ftrylockfile
56#pragma weak funlockfile=_funlockfile
49
57
58static int init_lock(FILE *);
59
50/*
60/*
51 * This function is a stub for the _flockfile function in libpthread.
61 * The FILE lock structure. The FILE *fp is locked when the mutex
62 * is locked.
52 */
63 */
64struct __file_lock {
65 pthread_mutex_t fl_mutex;
66 pthread_t fl_owner; /* current owner */
67 int fl_count; /* recursive lock count */
68};
69
70/*
71 * Allocate and initialize a file lock.
72 */
73static int
74init_lock(FILE *fp)
75{
76 struct __file_lock *p;
77 int ret;
78
79 if ((p = malloc(sizeof(struct __file_lock))) == NULL)
80 ret = -1;
81 else {
82 p->fl_mutex = PTHREAD_MUTEX_INITIALIZER;
83 p->fl_owner = NULL;
84 p->fl_count = 0;
85 fp->_lock = p;
86 ret = 0;
87 }
88 return (ret);
89}
90
53void
91void
54_flockfile_stub(FILE *fp)
92_flockfile(FILE *fp)
55{
93{
94 pthread_t curthread = _pthread_self();
95
96 /*
97 * Check if this is a real file with a valid lock, creating
98 * the lock if needed:
99 */
100 if ((fp->_file >= 0) &&
101 ((fp->_lock != NULL) || (init_lock(fp) == 0))) {
102 if (fp->_lock->fl_owner == curthread)
103 fp->_lock->fl_count++;
104 else {
105 /*
106 * Make sure this mutex is treated as a private
107 * internal mutex:
108 */
109 _pthread_mutex_lock(&fp->_lock->fl_mutex);
110 fp->_lock->fl_owner = curthread;
111 fp->_lock->fl_count = 1;
112 }
113 }
56}
57
58/*
114}
115
116/*
59 * This function is a stub for the _flockfile_debug function in libpthread.
117 * This can be overriden by the threads library if it is linked in.
60 */
61void
62_flockfile_debug_stub(FILE *fp, char *fname, int lineno)
63{
118 */
119void
120_flockfile_debug_stub(FILE *fp, char *fname, int lineno)
121{
122 _flockfile(fp);
64}
65
123}
124
66/*
67 * This function is a stub for the _ftrylockfile function in libpthread.
68 */
69int
125int
70_ftrylockfile_stub(FILE *fp)
126_ftrylockfile(FILE *fp)
71{
127{
72 return(0);
128 pthread_t curthread = _pthread_self();
129 int ret = 0;
130
131 /*
132 * Check if this is a real file with a valid lock, creating
133 * the lock if needed:
134 */
135 if ((fp->_file >= 0) &&
136 ((fp->_lock != NULL) || (init_lock(fp) == 0))) {
137 if (fp->_lock->fl_owner == curthread)
138 fp->_lock->fl_count++;
139 /*
140 * Make sure this mutex is treated as a private
141 * internal mutex:
142 */
143 else if (_pthread_mutex_trylock(&fp->_lock->fl_mutex) == 0) {
144 fp->_lock->fl_owner = curthread;
145 fp->_lock->fl_count = 1;
146 }
147 else
148 ret = -1;
149 }
150 else
151 ret = -1;
152 return (ret);
73}
74
153}
154
75/*
76 * This function is a stub for the _funlockfile function in libpthread.
77 */
78void
79_funlockfile_stub(FILE *fp)
155void
156_funlockfile(FILE *fp)
80{
157{
158 pthread_t curthread = _pthread_self();
159
160 /*
161 * Check if this is a real file with a valid lock owned
162 * by the current thread:
163 */
164 if ((fp->_file >= 0) && (fp->_lock != NULL) &&
165 (fp->_lock->fl_owner == curthread)) {
166 /*
167 * Check if this thread has locked the FILE
168 * more than once:
169 */
170 if (fp->_lock->fl_count > 1)
171 /*
172 * Decrement the count of the number of
173 * times the running thread has locked this
174 * file:
175 */
176 fp->_lock->fl_count--;
177 else {
178 /*
179 * The running thread will release the
180 * lock now:
181 */
182 fp->_lock->fl_count = 0;
183 fp->_lock->fl_owner = NULL;
184 _pthread_mutex_unlock(&fp->_lock->fl_mutex);
185 }
186 }
81}
187}