Annotation of prex-old/usr/lib/posix/process/fork.c, Revision 1.1
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>
! 40:
! 41: static void __child_entry(void);
! 42:
! 43: static jmp_buf __fork_env;
! 44:
! 45: /*
! 46: * fork() - fork for MMU system.
! 47: *
! 48: * RETURN VALUE:
! 49: *
! 50: * fork() returns 0 to the child process and return the process
! 51: * ID of the child process to the parent process. Or, -1 will be
! 52: * returned to the parent process if error.
! 53: *
! 54: * ERRORS:
! 55: *
! 56: * EAGAIN
! 57: * ENOMEM
! 58: *
! 59: * NOTE:
! 60: *
! 61: * Since no thread is created by task_create(), thread_create()
! 62: * must be called follwing task_crate(). But, when new thread is
! 63: * created by thread_create(), the stack pointer of new thread is
! 64: * used at thread_create() although the stack image is copied at
! 65: * task_create(). So, the stack pointer must be reset to same
! 66: * address of thread_create() before calling task_create();
! 67: * This is a little tricky...
! 68: *
! 69: * The new process is an exact copy of the calling process
! 70: * except as detailed below:
! 71: * - Process IDs are different.
! 72: * - tms_* is set to 0.
! 73: * - Alarm clock is set to 0.
! 74: * - Opend semaphore is inherited.
! 75: * - Pending signals are cleared.
! 76: *
! 77: * - File lock is not inherited.
! 78: * - File descriptor is same
! 79: * - Directory stream is same
! 80: */
! 81: static pid_t
! 82: fork(void)
! 83: {
! 84: struct msg m;
! 85: task_t tsk;
! 86: thread_t th;
! 87: int err;
! 88: pid_t pid;
! 89:
! 90: /* Save current stack pointer */
! 91: if (setjmp(__fork_env) == 0) {
! 92: /*
! 93: * Create new task
! 94: */
! 95: err = task_create(task_self(), VM_COPY, &tsk);
! 96: if (err) {
! 97: errno = err;
! 98: return -1;
! 99: }
! 100: if ((err = thread_create(tsk, &th)) != 0) {
! 101: task_terminate(tsk);
! 102: errno = err;
! 103: return -1;
! 104: }
! 105: /*
! 106: * Notify to process server
! 107: */
! 108: m.hdr.code = PS_FORK;
! 109: m.data[0] = tsk; /* child task */
! 110: m.data[1] = 0; /* fork type */
! 111: if (__posix_call(__proc_obj, &m, sizeof(m), 1) != 0)
! 112: return -1;
! 113: pid = m.data[0];
! 114:
! 115: /*
! 116: * Notify to file system server
! 117: */
! 118: m.hdr.code = FS_FORK;
! 119: m.data[0] = tsk; /* child task */
! 120: if (__posix_call(__fs_obj, &m, sizeof(m), 1) != 0)
! 121: return -1;
! 122:
! 123: /*
! 124: * Start child task
! 125: */
! 126: thread_load(th, __child_entry, NULL);
! 127: thread_resume(th);
! 128: } else {
! 129: /*
! 130: * Child task
! 131: */
! 132: #ifdef _REENTRANT
! 133: err = mutex_init(&__sig_lock);
! 134: #endif
! 135: __sig_pending = 0;
! 136: return 0;
! 137: }
! 138: return pid;
! 139: }
! 140:
! 141: static void
! 142: __child_entry(void)
! 143: {
! 144:
! 145: longjmp(__fork_env, 1);
! 146: /* NOTREACHED */
! 147: }
! 148:
! 149: pid_t
! 150: vfork(void)
! 151: {
! 152:
! 153: return fork();
! 154: }
! 155:
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