root / prex-0.9.0 / usr / lib / posix / process / fork.c @ 03e9c04a
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/*
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* Copyright (c) 2005-2006, Kohsuke Ohtani
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the name of the author nor the names of any co-contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include <sys/prex.h> |
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#include <sys/posix.h> |
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#include <sys/signal.h> |
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#include <ipc/proc.h> |
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#include <ipc/fs.h> |
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#include <ipc/ipc.h> |
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#include <stddef.h> |
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#include <setjmp.h> |
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#include <errno.h> |
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#include <unistd.h> |
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static void __child_entry(void); |
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static jmp_buf __fork_env;
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/*
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* fork() - fork for MMU system.
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*
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* RETURN VALUE:
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*
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* fork() returns 0 to the child process and return the process
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* ID of the child process to the parent process. Or, -1 will be
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* returned to the parent process if error.
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*
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* ERRORS:
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*
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* EAGAIN
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* ENOMEM
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*
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* NOTE:
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*
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* Since no thread is created by task_create(), thread_create()
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* must be called follwing task_crate(). But, when new thread is
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* created by thread_create(), the stack pointer of new thread is
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* used at thread_create() although the stack image is copied at
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* task_create(). So, the stack pointer must be reset to same
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* address of thread_create() before calling task_create();
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* This is a little tricky...
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*
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* The new process is an exact copy of the calling process
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* except as detailed below:
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* - Process IDs are different.
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* - tms_* is set to 0.
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* - Alarm clock is set to 0.
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* - Opend semaphore is inherited.
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* - Pending signals are cleared.
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*
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* - File lock is not inherited.
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* - File descriptor is shared.
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* - Directory stream is shared.
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*/
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static pid_t
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fork(void)
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{ |
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struct msg m;
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task_t tsk; |
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thread_t t; |
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int error;
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pid_t pid; |
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/* Save current stack pointer */
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if (setjmp(__fork_env) == 0) { |
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/*
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* Create new task
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*/
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error = task_create(task_self(), VM_COPY, &tsk); |
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if (error) {
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errno = error; |
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return -1; |
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} |
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if ((error = thread_create(tsk, &t)) != 0) { |
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task_terminate(tsk); |
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errno = error; |
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return -1; |
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} |
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/*
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* Notify to process server
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*/
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m.hdr.code = PS_FORK; |
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m.data[0] = tsk; /* child task */ |
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m.data[1] = 0; /* fork type */ |
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if (__posix_call(__proc_obj, &m, sizeof(m), 1) != 0) |
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return -1; |
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pid = m.data[0];
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/*
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* Notify to file system server
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*/
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m.hdr.code = FS_FORK; |
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m.data[0] = tsk; /* child task */ |
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if (__posix_call(__fs_obj, &m, sizeof(m), 1) != 0) |
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return -1; |
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/*
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* Start child task
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*/
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thread_load(t, __child_entry, NULL);
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thread_resume(t); |
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} else {
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/*
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* Child task
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*/
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#ifdef _REENTRANT
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error = mutex_init(&__sig_lock); |
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#endif
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__sig_pending = 0;
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return 0; |
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} |
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return pid;
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} |
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static void |
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__child_entry(void)
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{ |
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longjmp(__fork_env, 1);
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/* NOTREACHED */
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} |
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pid_t |
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vfork(void)
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{ |
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return fork();
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} |
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