root / prex-0.9.0 / usr / server / proc / proc_fork.c @ 03e9c04a
History | View | Annotate | Download (4.62 KB)
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 |
/*
|
31 |
* fork.c - fork() support
|
32 |
*/
|
33 |
|
34 |
#include <sys/prex.h> |
35 |
#include <ipc/proc.h> |
36 |
#include <sys/list.h> |
37 |
|
38 |
#include <unistd.h> |
39 |
#include <errno.h> |
40 |
#include <stdlib.h> |
41 |
#include <string.h> |
42 |
|
43 |
#include "proc.h" |
44 |
|
45 |
static int vfork_start(struct proc *); |
46 |
|
47 |
/*
|
48 |
* PID previously allocated.
|
49 |
*
|
50 |
* Note: The following pids are reserved by default.
|
51 |
* pid = 0: Process server
|
52 |
* pid = 1: Init process
|
53 |
*/
|
54 |
static pid_t last_pid = 1; |
55 |
|
56 |
/*
|
57 |
* Assign new pid.
|
58 |
* Returns pid on sucess, or 0 on failure.
|
59 |
*/
|
60 |
static pid_t
|
61 |
pid_alloc(void)
|
62 |
{ |
63 |
pid_t pid; |
64 |
|
65 |
pid = last_pid + 1;
|
66 |
if (pid >= PID_MAX)
|
67 |
pid = 1;
|
68 |
while (pid != last_pid) {
|
69 |
if (p_find(pid) == NULL) |
70 |
break;
|
71 |
if (++pid >= PID_MAX)
|
72 |
pid = 1;
|
73 |
} |
74 |
if (pid == last_pid)
|
75 |
return 0; |
76 |
last_pid = pid; |
77 |
return pid;
|
78 |
} |
79 |
|
80 |
/*
|
81 |
* Create a new process.
|
82 |
*/
|
83 |
int
|
84 |
newproc(struct proc *p, pid_t pid, task_t task)
|
85 |
{ |
86 |
struct pgrp *pg;
|
87 |
|
88 |
pg = curproc->p_pgrp; |
89 |
|
90 |
if (pid == 0) { |
91 |
pid = pid_alloc(); |
92 |
if (pid == 0) { |
93 |
/* Too many processes */
|
94 |
return EAGAIN;
|
95 |
} |
96 |
} |
97 |
/*
|
98 |
* make proc entry for new proc
|
99 |
*/
|
100 |
p->p_parent = curproc; |
101 |
p->p_pgrp = pg; |
102 |
p->p_stat = SRUN; |
103 |
p->p_exitcode = 0;
|
104 |
p->p_pid = pid; |
105 |
p->p_task = task; |
106 |
p->p_vforked = 0;
|
107 |
p->p_invfork = 0;
|
108 |
|
109 |
list_init(&p->p_children); |
110 |
p_add(p); |
111 |
list_insert(&curproc->p_children, &p->p_sibling); |
112 |
list_insert(&pg->pg_members, &p->p_pgrp_link); |
113 |
list_insert(&allproc, &p->p_link); |
114 |
|
115 |
return 0; |
116 |
} |
117 |
|
118 |
/*
|
119 |
* fork() support.
|
120 |
*
|
121 |
* It creates new process data and update all process relations.
|
122 |
* The task creation and the thread creation are done by the
|
123 |
* fork() library stub.
|
124 |
*/
|
125 |
int
|
126 |
sys_fork(task_t child, int vfork, pid_t *retval)
|
127 |
{ |
128 |
struct proc *p;
|
129 |
int error;
|
130 |
|
131 |
DPRINTF(("proc: fork child=%x vfork=%d\n", child, vfork));
|
132 |
|
133 |
if (vfork && curproc->p_invfork) {
|
134 |
DPRINTF(("proc: vfork under vfork!\n"));
|
135 |
return EINVAL;
|
136 |
} |
137 |
|
138 |
if (task_to_proc(child) != NULL) { |
139 |
DPRINTF(("proc: process already exists\n"));
|
140 |
return EINVAL;
|
141 |
} |
142 |
|
143 |
if ((p = malloc(sizeof(struct proc))) == NULL) |
144 |
return ENOMEM;
|
145 |
memset(p, 0, sizeof(*p)); |
146 |
|
147 |
error = newproc(p, 0, child);
|
148 |
if (error)
|
149 |
return error;
|
150 |
|
151 |
if (vfork) {
|
152 |
vfork_start(curproc); |
153 |
p->p_invfork = 1;
|
154 |
} |
155 |
|
156 |
DPRINTF(("proc: fork newpid=%d\n", p->p_pid));
|
157 |
*retval = p->p_pid; |
158 |
return 0; |
159 |
} |
160 |
|
161 |
/*
|
162 |
* Clean up all resource created by fork().
|
163 |
*/
|
164 |
void
|
165 |
cleanup(struct proc *p)
|
166 |
{ |
167 |
struct proc *pp;
|
168 |
|
169 |
DPRINTF(("proc: cleanup pid=%d\n", p->p_pid));
|
170 |
pp = p->p_parent; |
171 |
list_remove(&p->p_sibling); |
172 |
list_remove(&p->p_pgrp_link); |
173 |
list_remove(&p->p_link); |
174 |
free(p); |
175 |
} |
176 |
|
177 |
static int |
178 |
vfork_start(struct proc *p)
|
179 |
{ |
180 |
void *stack;
|
181 |
|
182 |
/*
|
183 |
* Save parent's stack
|
184 |
*/
|
185 |
DPRINTF(("proc: vfork_start stack=%x\n", p->p_stackbase));
|
186 |
|
187 |
if (vm_allocate(p->p_task, &stack, DFLSTKSZ, 1) != 0) { |
188 |
DPRINTF(("proc: failed to allocate save stack\n"));
|
189 |
return ENOMEM;
|
190 |
} |
191 |
|
192 |
memcpy(stack, p->p_stackbase, DFLSTKSZ); |
193 |
p->p_stacksaved = stack; |
194 |
|
195 |
p->p_vforked = 1;
|
196 |
return 0; |
197 |
} |
198 |
|
199 |
void
|
200 |
vfork_end(struct proc *p)
|
201 |
{ |
202 |
|
203 |
DPRINTF(("proc: vfork_end org=%x saved=%x\n", p->p_stackbase,
|
204 |
p->p_stacksaved)); |
205 |
/*
|
206 |
* Restore parent's stack
|
207 |
*/
|
208 |
memcpy(p->p_stackbase, p->p_stacksaved, DFLSTKSZ); |
209 |
vm_free(p->p_task, p->p_stacksaved); |
210 |
|
211 |
/*
|
212 |
* Resume parent
|
213 |
*/
|
214 |
p->p_vforked = 0;
|
215 |
task_resume(p->p_task); |
216 |
} |