filedup.c revision 269847 
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#include "apr_strings.h"
19#include "apr_portable.h"
20#include "apr_thread_mutex.h"
21#include "apr_arch_inherit.h"
22
23static apr_status_t file_dup(apr_file_t **new_file,
24                             apr_file_t *old_file, apr_pool_t *p,
25                             int which_dup)
26{
27    int rv;
28#ifdef HAVE_DUP3
29    int flags = 0;
30#endif
31
32    if (which_dup == 2) {
33        if ((*new_file) == NULL) {
34            /* We can't dup2 unless we have a valid new_file */
35            return APR_EINVAL;
36        }
37#ifdef HAVE_DUP3
38        if (!((*new_file)->flags & (APR_FOPEN_NOCLEANUP|APR_INHERIT)))
39            flags |= O_CLOEXEC;
40        rv = dup3(old_file->filedes, (*new_file)->filedes, flags);
41#else
42        rv = dup2(old_file->filedes, (*new_file)->filedes);
43        if (!((*new_file)->flags & (APR_FOPEN_NOCLEANUP|APR_INHERIT))) {
44            int flags;
45
46            if (rv == -1)
47                return errno;
48
49            if ((flags = fcntl((*new_file)->filedes, F_GETFD)) == -1)
50                return errno;
51
52            flags |= FD_CLOEXEC;
53            if (fcntl((*new_file)->filedes, F_SETFD, flags) == -1)
54                return errno;
55
56        }
57#endif
58    } else {
59        rv = dup(old_file->filedes);
60    }
61
62    if (rv == -1)
63        return errno;
64
65    if (which_dup == 1) {
66        (*new_file) = (apr_file_t *)apr_pcalloc(p, sizeof(apr_file_t));
67        (*new_file)->pool = p;
68        (*new_file)->filedes = rv;
69    }
70
71    (*new_file)->fname = apr_pstrdup(p, old_file->fname);
72    (*new_file)->buffered = old_file->buffered;
73
74    /* If the existing socket in a dup2 is already buffered, we
75     * have an existing and valid (hopefully) mutex, so we don't
76     * want to create it again as we could leak!
77     */
78#if APR_HAS_THREADS
79    if ((*new_file)->buffered && !(*new_file)->thlock && old_file->thlock) {
80        apr_thread_mutex_create(&((*new_file)->thlock),
81                                APR_THREAD_MUTEX_DEFAULT, p);
82    }
83#endif
84    /* As above, only create the buffer if we haven't already
85     * got one.
86     */
87    if ((*new_file)->buffered && !(*new_file)->buffer) {
88        (*new_file)->buffer = apr_palloc(p, old_file->bufsize);
89        (*new_file)->bufsize = old_file->bufsize;
90    }
91
92    /* this is the way dup() works */
93    (*new_file)->blocking = old_file->blocking;
94
95    /* make sure unget behavior is consistent */
96    (*new_file)->ungetchar = old_file->ungetchar;
97
98    /* apr_file_dup2() retains the original cleanup, reflecting
99     * the existing inherit and nocleanup flags.  This means,
100     * that apr_file_dup2() cannot be called against an apr_file_t
101     * already closed with apr_file_close, because the expected
102     * cleanup was already killed.
103     */
104    if (which_dup == 2) {
105        return APR_SUCCESS;
106    }
107
108    /* apr_file_dup() retains all old_file flags with the exceptions
109     * of APR_INHERIT and APR_FOPEN_NOCLEANUP.
110     * The user must call apr_file_inherit_set() on the dupped
111     * apr_file_t when desired.
112     */
113    (*new_file)->flags = old_file->flags
114                       & ~(APR_INHERIT | APR_FOPEN_NOCLEANUP);
115
116    apr_pool_cleanup_register((*new_file)->pool, (void *)(*new_file),
117                              apr_unix_file_cleanup,
118                              apr_unix_child_file_cleanup);
119#ifndef WAITIO_USES_POLL
120    /* Start out with no pollset.  apr_wait_for_io_or_timeout() will
121     * initialize the pollset if needed.
122     */
123    (*new_file)->pollset = NULL;
124#endif
125    return APR_SUCCESS;
126}
127
128APR_DECLARE(apr_status_t) apr_file_dup(apr_file_t **new_file,
129                                       apr_file_t *old_file, apr_pool_t *p)
130{
131    return file_dup(new_file, old_file, p, 1);
132}
133
134APR_DECLARE(apr_status_t) apr_file_dup2(apr_file_t *new_file,
135                                        apr_file_t *old_file, apr_pool_t *p)
136{
137    return file_dup(&new_file, old_file, p, 2);
138}
139
140APR_DECLARE(apr_status_t) apr_file_setaside(apr_file_t **new_file,
141                                            apr_file_t *old_file,
142                                            apr_pool_t *p)
143{
144    *new_file = (apr_file_t *)apr_pmemdup(p, old_file, sizeof(apr_file_t));
145    (*new_file)->pool = p;
146    if (old_file->buffered) {
147        (*new_file)->buffer = apr_palloc(p, old_file->bufsize);
148        (*new_file)->bufsize = old_file->bufsize;
149        if (old_file->direction == 1) {
150            memcpy((*new_file)->buffer, old_file->buffer, old_file->bufpos);
151        }
152        else {
153            memcpy((*new_file)->buffer, old_file->buffer, old_file->dataRead);
154        }
155#if APR_HAS_THREADS
156        if (old_file->thlock) {
157            apr_thread_mutex_create(&((*new_file)->thlock),
158                                    APR_THREAD_MUTEX_DEFAULT, p);
159            apr_thread_mutex_destroy(old_file->thlock);
160        }
161#endif /* APR_HAS_THREADS */
162    }
163    if (old_file->fname) {
164        (*new_file)->fname = apr_pstrdup(p, old_file->fname);
165    }
166    if (!(old_file->flags & APR_FOPEN_NOCLEANUP)) {
167        apr_pool_cleanup_register(p, (void *)(*new_file),
168                                  apr_unix_file_cleanup,
169                                  ((*new_file)->flags & APR_INHERIT)
170                                     ? apr_pool_cleanup_null
171                                     : apr_unix_child_file_cleanup);
172    }
173
174    old_file->filedes = -1;
175    apr_pool_cleanup_kill(old_file->pool, (void *)old_file,
176                          apr_unix_file_cleanup);
177#ifndef WAITIO_USES_POLL
178    (*new_file)->pollset = NULL;
179#endif
180    return APR_SUCCESS;
181}
182