Annotation of prex-old/usr/lib/posix/process/fork.c, Revision 1.1.1.1.2.1
1.1 nbrk 1: /*
2: * Copyright (c) 2005-2006, Kohsuke Ohtani
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: * 2. Redistributions in binary form must reproduce the above copyright
11: * notice, this list of conditions and the following disclaimer in the
12: * documentation and/or other materials provided with the distribution.
13: * 3. Neither the name of the author nor the names of any co-contributors
14: * may be used to endorse or promote products derived from this software
15: * without specific prior written permission.
16: *
17: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20: * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27: * SUCH DAMAGE.
28: */
29:
30: #include <prex/prex.h>
31: #include <prex/posix.h>
32: #include <prex/signal.h>
33: #include <server/proc.h>
34: #include <server/fs.h>
35: #include <server/stdmsg.h>
36:
37: #include <stddef.h>
38: #include <setjmp.h>
39: #include <errno.h>
1.1.1.1.2.1! nbrk 40: #include <unistd.h>
1.1 nbrk 41:
42: static void __child_entry(void);
43:
44: static jmp_buf __fork_env;
45:
46: /*
47: * fork() - fork for MMU system.
48: *
49: * RETURN VALUE:
50: *
51: * fork() returns 0 to the child process and return the process
52: * ID of the child process to the parent process. Or, -1 will be
53: * returned to the parent process if error.
54: *
55: * ERRORS:
56: *
57: * EAGAIN
58: * ENOMEM
59: *
60: * NOTE:
61: *
62: * Since no thread is created by task_create(), thread_create()
63: * must be called follwing task_crate(). But, when new thread is
64: * created by thread_create(), the stack pointer of new thread is
65: * used at thread_create() although the stack image is copied at
66: * task_create(). So, the stack pointer must be reset to same
67: * address of thread_create() before calling task_create();
68: * This is a little tricky...
69: *
70: * The new process is an exact copy of the calling process
71: * except as detailed below:
72: * - Process IDs are different.
73: * - tms_* is set to 0.
74: * - Alarm clock is set to 0.
75: * - Opend semaphore is inherited.
76: * - Pending signals are cleared.
77: *
78: * - File lock is not inherited.
79: * - File descriptor is same
80: * - Directory stream is same
81: */
82: static pid_t
83: fork(void)
84: {
85: struct msg m;
86: task_t tsk;
87: thread_t th;
88: int err;
89: pid_t pid;
90:
91: /* Save current stack pointer */
92: if (setjmp(__fork_env) == 0) {
93: /*
94: * Create new task
95: */
96: err = task_create(task_self(), VM_COPY, &tsk);
97: if (err) {
98: errno = err;
99: return -1;
100: }
101: if ((err = thread_create(tsk, &th)) != 0) {
102: task_terminate(tsk);
103: errno = err;
104: return -1;
105: }
106: /*
107: * Notify to process server
108: */
109: m.hdr.code = PS_FORK;
110: m.data[0] = tsk; /* child task */
111: m.data[1] = 0; /* fork type */
112: if (__posix_call(__proc_obj, &m, sizeof(m), 1) != 0)
113: return -1;
114: pid = m.data[0];
115:
116: /*
117: * Notify to file system server
118: */
119: m.hdr.code = FS_FORK;
120: m.data[0] = tsk; /* child task */
121: if (__posix_call(__fs_obj, &m, sizeof(m), 1) != 0)
122: return -1;
123:
124: /*
125: * Start child task
126: */
127: thread_load(th, __child_entry, NULL);
128: thread_resume(th);
129: } else {
130: /*
131: * Child task
132: */
133: #ifdef _REENTRANT
134: err = mutex_init(&__sig_lock);
135: #endif
136: __sig_pending = 0;
137: return 0;
138: }
139: return pid;
140: }
141:
142: static void
143: __child_entry(void)
144: {
145:
146: longjmp(__fork_env, 1);
147: /* NOTREACHED */
148: }
149:
150: pid_t
151: vfork(void)
152: {
153:
154: return fork();
155: }
156:
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