File: [local] / prex-old / usr / server / proc / fork.c (download)
Revision 1.1.1.1 (vendor branch), Tue Jun 3 09:38:51 2008 UTC (16 years ago) by nbrk
Branch: MAIN, KOHSUKE
CVS Tags: PREX_0_7_BASE, HEAD Branch point for: PREX_0_8_BASE
Changes since 1.1: +0 -0 lines
Yeah, this is an initial import of Prex, portable real-time microkernel
operating system. I wanna hack it for non-profit but fun, so let it in.
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/*
* Copyright (c) 2005-2006, Kohsuke Ohtani
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. Neither the name of the author nor the names of any co-contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*/
/*
* fork.c - fork() support
*/
#include <prex/prex.h>
#include <server/proc.h>
#include <sys/list.h>
#include <unistd.h>
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include "proc.h"
static int vfork_start(struct proc *proc);
/*
* fork() support.
*
* It creates new process data and update all process relations.
* The task creation and the thread creation are done by the fork()
* library stub.
*/
int
proc_fork(struct msg *msg)
{
struct proc *p;
struct pgrp *pgrp;
task_t child;
pid_t pid;
int vfork;
if (curproc == NULL)
return EINVAL;
child = (task_t)msg->data[0];
vfork = msg->data[1];
dprintf("fork: parent=%x child=%x vfork=%d\n",
msg->hdr.task, child, vfork);
if (task_to_proc(child) != NULL)
return EINVAL; /* Process already exists */
if ((pid = pid_assign()) == 0)
return EAGAIN; /* Too many processes */
if ((p = malloc(sizeof(struct proc))) == NULL)
return ENOMEM;
p->parent = curproc;
p->pgrp = curproc->pgrp;
p->stat = SRUN;
p->exit_code = 0;
p->pid = pid;
p->task = child;
list_init(&p->children);
proc_add(p);
list_insert(&curproc->children, &p->sibling);
pgrp = p->pgrp;
list_insert(&pgrp->members, &p->pgrp_link);
list_insert(&allproc, &p->link);
if (vfork)
vfork_start(curproc);
dprintf("fork: new pid=%d\n", p->pid);
msg->data[0] = (int)p->pid;
return 0;
}
/*
* Clean up all resource created by fork().
*/
void
proc_cleanup(struct proc *proc)
{
struct proc *pp;
pp = proc->parent;
list_remove(&proc->sibling);
list_remove(&proc->pgrp_link);
proc_remove(proc);
list_remove(&proc->link);
free(proc);
}
static int
vfork_start(struct proc *proc)
{
void *stack;
/*
* Save parent's stack
*/
if (vm_allocate(proc->task, &stack, USTACK_SIZE, 1) != 0)
return ENOMEM;
memcpy(stack, proc->stack_base, USTACK_SIZE);
proc->stack_saved = stack;
proc->wait_vfork = 1;
dprintf("vfork_start: saved=%x org=%x\n", stack, proc->stack_base);
return 0;
}
void
vfork_end(struct proc *proc)
{
dprintf("vfork_end: org=%x saved=%x\n", proc->stack_base,
proc->stack_saved);
/*
* Restore parent's stack
*/
memcpy(proc->stack_base, proc->stack_saved, USTACK_SIZE);
vm_free(proc->task, proc->stack_saved);
/*
* Resume parent
*/
proc->wait_vfork = 0;
task_resume(proc->task);
}