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_threadproc.h"
18
19APR_DECLARE(apr_status_t) apr_proc_detach(int daemonize)
20{
21    if (chdir("/") == -1) {
22        return errno;
23    }
24
25#if !defined(MPE) && !defined(OS2) && !defined(TPF) && !defined(BEOS)
26    /* Don't detach for MPE because child processes can't survive the death of
27     * the parent. */
28    if (daemonize) {
29        int x;
30
31        if ((x = fork()) > 0) {
32            exit(0);
33        }
34        else if (x == -1) {
35            perror("fork");
36            fprintf(stderr, "unable to fork new process\n");
37            exit(1);  /* we can't do anything here, so just exit. */
38        }
39        /* RAISE_SIGSTOP(DETACH); */
40    }
41#endif
42
43#ifdef HAVE_SETSID
44    /* A setsid() failure is not fatal if we didn't just fork().
45     * The calling process may be the process group leader, in
46     * which case setsid() will fail with EPERM.
47     */
48    if (setsid() == -1 && daemonize) {
49        return errno;
50    }
51#elif defined(NEXT) || defined(NEWSOS)
52    if (setpgrp(0, getpid()) == -1) {
53        return errno;
54    }
55#elif defined(OS2) || defined(TPF) || defined(MPE)
56    /* do nothing */
57#else
58    if (setpgid(0, 0) == -1) {
59        return errno;
60    }
61#endif
62
63    /* close out the standard file descriptors */
64    if (freopen("/dev/null", "r", stdin) == NULL) {
65        return errno;
66        /* continue anyhow -- note we can't close out descriptor 0 because we
67         * have nothing to replace it with, and if we didn't have a descriptor
68         * 0 the next file would be created with that value ... leading to
69         * havoc.
70         */
71    }
72    if (freopen("/dev/null", "w", stdout) == NULL) {
73        return errno;
74    }
75     /* We are going to reopen this again in a little while to the error
76      * log file, but better to do it twice and suffer a small performance
77      * hit for consistancy than not reopen it here.
78      */
79    if (freopen("/dev/null", "w", stderr) == NULL) {
80        return errno;
81    }
82    return APR_SUCCESS;
83}
84
85#if (!HAVE_WAITPID)
86/* From ikluft@amdahl.com
87 * this is not ideal but it works for SVR3 variants
88 * Modified by dwd@bell-labs.com to call wait3 instead of wait because
89 *   apache started to use the WNOHANG option.
90 */
91int waitpid(pid_t pid, int *statusp, int options)
92{
93    int tmp_pid;
94    if (kill(pid, 0) == -1) {
95        errno = ECHILD;
96        return -1;
97    }
98    while (((tmp_pid = wait3(statusp, options, 0)) != pid) &&
99                (tmp_pid != -1) && (tmp_pid != 0) && (pid != -1))
100        ;
101    return tmp_pid;
102}
103#endif
104
105