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1.1 root 1: /*
2: * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
3: *
4: * @APPLE_LICENSE_HEADER_START@
5: *
6: * The contents of this file constitute Original Code as defined in and
7: * are subject to the Apple Public Source License Version 1.1 (the
8: * "License"). You may not use this file except in compliance with the
9: * License. Please obtain a copy of the License at
10: * http://www.apple.com/publicsource and read it before using this file.
11: *
12: * This Original Code and all software distributed under the License are
13: * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
14: * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
15: * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
16: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
17: * License for the specific language governing rights and limitations
18: * under the License.
19: *
20: * @APPLE_LICENSE_HEADER_END@
21: */
22: /* Copyright (c) 1995, 1997 Apple Computer, Inc. All Rights Reserved */
23: /*
24: * Copyright (c) 1982, 1986, 1989, 1991, 1993
25: * The Regents of the University of California. All rights reserved.
26: * (c) UNIX System Laboratories, Inc.
27: * All or some portions of this file are derived from material licensed
28: * to the University of California by American Telephone and Telegraph
29: * Co. or Unix System Laboratories, Inc. and are reproduced herein with
30: * the permission of UNIX System Laboratories, Inc.
31: *
32: * Redistribution and use in source and binary forms, with or without
33: * modification, are permitted provided that the following conditions
34: * are met:
35: * 1. Redistributions of source code must retain the above copyright
36: * notice, this list of conditions and the following disclaimer.
37: * 2. Redistributions in binary form must reproduce the above copyright
38: * notice, this list of conditions and the following disclaimer in the
39: * documentation and/or other materials provided with the distribution.
40: * 3. All advertising materials mentioning features or use of this software
41: * must display the following acknowledgement:
42: * This product includes software developed by the University of
43: * California, Berkeley and its contributors.
44: * 4. Neither the name of the University nor the names of its contributors
45: * may be used to endorse or promote products derived from this software
46: * without specific prior written permission.
47: *
48: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
49: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
50: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
51: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
52: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
53: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
54: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
55: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
56: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
57: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
58: * SUCH DAMAGE.
59: *
60: * @(#)kern_fork.c 8.8 (Berkeley) 2/14/95
61: */
62:
63: #include <sys/param.h>
64: #include <sys/systm.h>
65: #include <sys/filedesc.h>
66: #include <sys/kernel.h>
67: #include <sys/malloc.h>
68: #include <sys/proc.h>
69: #include <sys/user.h>
70: #include <sys/resourcevar.h>
71: #include <sys/vnode.h>
72: #include <sys/file.h>
73: #include <sys/acct.h>
74: #include <sys/ktrace.h>
75:
76: #import <mach/mach_types.h>
77: #import <kern/mach_param.h>
78:
79: #import <machine/spl.h>
80:
81: thread_t cloneproc(), procdup();
82:
83: #define DOFORK 0x1 /* fork() system call */
84: #define DOVFORK 0x2 /* vfork() system call */
85: static int fork1(struct proc *, long, register_t *);
86:
87: /*
88: * fork system call.
89: */
90: int
91: fork(p, uap, retval)
92: struct proc *p;
93: void *uap;
94: register_t *retval;
95: {
96: return (fork1(p, (long)DOFORK, retval));
97: }
98:
99: /*
100: * vfork system call
101: */
102: int
103: vfork(p, uap, retval)
104: struct proc *p;
105: void *uap;
106: register_t *retval;
107: {
108: return (fork1(p, (long)DOVFORK, retval));
109: }
110:
111: static int
112: fork1(p1, flags, retval)
113: struct proc *p1;
114: long flags;
115: register_t *retval;
116: {
117: register struct proc *p2;
118: register uid_t uid;
119: thread_t newth, self = current_thread();
120: int s, count;
121:
122: /*
123: * Although process entries are dynamically created, we still keep
124: * a global limit on the maximum number we will create. Don't allow
125: * a nonprivileged user to use the last process; don't let root
126: * exceed the limit. The variable nprocs is the current number of
127: * processes, maxproc is the limit.
128: */
129: uid = p1->p_cred->p_ruid;
130: if ((nprocs >= maxproc - 1 && uid != 0) || nprocs >= maxproc) {
131: tablefull("proc");
132: retval[1] = 0;
133: return (EAGAIN);
134: }
135:
136: /*
137: * Increment the count of procs running with this uid. Don't allow
138: * a nonprivileged user to exceed their current limit.
139: */
140: count = chgproccnt(uid, 1);
141: if (uid != 0 && count > p1->p_rlimit[RLIMIT_NPROC].rlim_cur) {
142: (void)chgproccnt(uid, -1);
143: return (EAGAIN);
144: }
145:
146: newth = cloneproc(p1);
147: thread_dup(current_act(), newth);
148: /* p2 = newth->task->proc; */
149: p2 = (struct proc *)(get_bsdtask_info(get_threadtask(newth)));
150:
151: thread_set_child(newth, p2->p_pid);
152:
153: s = splhigh();
154: p2->p_stats->p_start = time;
155: splx(s);
156: p2->p_acflag = AFORK;
157:
158: /*
159: * Preserve synchronization semantics of vfork. If waiting for
160: * child to exec or exit, set P_PPWAIT on child, and sleep on our
161: * proc (in case of exit).
162: */
163: if (flags == DOVFORK)
164: p2->p_flag |= P_PPWAIT;
165:
166: (void) thread_resume(newth);
167:
168: while (p2->p_flag & P_PPWAIT)
169: tsleep(p1, PWAIT, "ppwait", 0);
170:
171: retval[0] = p2->p_pid;
172: retval[1] = 0; /* mark parent */
173:
174: return (0);
175: }
176:
177: /*
178: * cloneproc()
179: *
180: * Create a new process from a specified process.
181: */
182: thread_t
183: cloneproc(p1)
184: register struct proc *p1;
185: {
186: register struct proc *p2, *newproc;
187: static int nextpid = 0, pidchecked = 0;
188: thread_t th;
189:
190: /* Allocate new proc. */
191: MALLOC_ZONE(newproc, struct proc *,
192: sizeof *newproc, M_PROC, M_WAITOK);
193: MALLOC_ZONE(newproc->p_cred, struct pcred *,
194: sizeof *newproc->p_cred, M_SUBPROC, M_WAITOK);
195: MALLOC_ZONE(newproc->p_stats, struct pstats *,
196: sizeof *newproc->p_stats, M_SUBPROC, M_WAITOK);
197: MALLOC_ZONE(newproc->p_sigacts, struct sigacts *,
198: sizeof *newproc->p_sigacts, M_SUBPROC, M_WAITOK);
199:
200: /*
201: * Find an unused process ID. We remember a range of unused IDs
202: * ready to use (from nextpid+1 through pidchecked-1).
203: */
204: nextpid++;
205: retry:
206: /*
207: * If the process ID prototype has wrapped around,
208: * restart somewhat above 0, as the low-numbered procs
209: * tend to include daemons that don't exit.
210: */
211: if (nextpid >= PID_MAX) {
212: nextpid = 100;
213: pidchecked = 0;
214: }
215: if (nextpid >= pidchecked) {
216: int doingzomb = 0;
217:
218: pidchecked = PID_MAX;
219: /*
220: * Scan the active and zombie procs to check whether this pid
221: * is in use. Remember the lowest pid that's greater
222: * than nextpid, so we can avoid checking for a while.
223: */
224: p2 = allproc.lh_first;
225: again:
226: for (; p2 != 0; p2 = p2->p_list.le_next) {
227: while (p2->p_pid == nextpid ||
228: p2->p_pgrp->pg_id == nextpid) {
229: nextpid++;
230: if (nextpid >= pidchecked)
231: goto retry;
232: }
233: if (p2->p_pid > nextpid && pidchecked > p2->p_pid)
234: pidchecked = p2->p_pid;
235: if (p2->p_pgrp->pg_id > nextpid &&
236: pidchecked > p2->p_pgrp->pg_id)
237: pidchecked = p2->p_pgrp->pg_id;
238: }
239: if (!doingzomb) {
240: doingzomb = 1;
241: p2 = zombproc.lh_first;
242: goto again;
243: }
244: }
245:
246: nprocs++;
247: p2 = newproc;
248: p2->p_stat = SIDL;
249: p2->p_pid = nextpid;
250:
251: /*
252: * Make a proc table entry for the new process.
253: * Start by zeroing the section of proc that is zero-initialized,
254: * then copy the section that is copied directly from the parent.
255: */
256: bzero(&p2->p_startzero,
257: (unsigned) ((caddr_t)&p2->p_endzero - (caddr_t)&p2->p_startzero));
258: bcopy(&p1->p_startcopy, &p2->p_startcopy,
259: (unsigned) ((caddr_t)&p2->p_endcopy - (caddr_t)&p2->p_startcopy));
260: p2->vm_shm = (void *)NULL; /* Make sure it is zero */
261:
262: /*
263: * Duplicate sub-structures as needed.
264: * Increase reference counts on shared objects.
265: * The p_stats and p_sigacts substructs are set in vm_fork.
266: */
267: p2->p_flag = P_INMEM;
268: if (p1->p_flag & P_PROFIL)
269: startprofclock(p2);
270: bcopy(p1->p_cred, p2->p_cred, sizeof(*p2->p_cred));
271: p2->p_cred->p_refcnt = 1;
272: crhold(p1->p_ucred);
273: lockinit(&p2->p_cred->pc_lock, PLOCK, "proc cred", 0, 0);
274:
275: /* bump references to the text vnode (for procfs) */
276: p2->p_textvp = p1->p_textvp;
277: if (p2->p_textvp)
278: VREF(p2->p_textvp);
279:
280: p2->p_fd = fdcopy(p1);
281: if (p1->vm_shm) {
282: shmfork(p1,p2);
283: }
284: /*
285: * If p_limit is still copy-on-write, bump refcnt,
286: * otherwise get a copy that won't be modified.
287: * (If PL_SHAREMOD is clear, the structure is shared
288: * copy-on-write.)
289: */
290: if (p1->p_limit->p_lflags & PL_SHAREMOD)
291: p2->p_limit = limcopy(p1->p_limit);
292: else {
293: p2->p_limit = p1->p_limit;
294: p2->p_limit->p_refcnt++;
295: }
296:
297: bzero(&p2->p_stats->pstat_startzero,
298: (unsigned) ((caddr_t)&p2->p_stats->pstat_endzero -
299: (caddr_t)&p2->p_stats->pstat_startzero));
300: bcopy(&p1->p_stats->pstat_startcopy, &p2->p_stats->pstat_startcopy,
301: ((caddr_t)&p2->p_stats->pstat_endcopy -
302: (caddr_t)&p2->p_stats->pstat_startcopy));
303:
304: if (p1->p_sigacts != NULL)
305: (void)memcpy(p2->p_sigacts,
306: p1->p_sigacts, sizeof *p2->p_sigacts);
307: else
308: (void)memset(p2->p_sigacts, 0, sizeof *p2->p_sigacts);
309:
310: if (p1->p_session->s_ttyvp != NULL && p1->p_flag & P_CONTROLT)
311: p2->p_flag |= P_CONTROLT;
312:
313: p2->p_xstat = 0;
314: p2->p_ru = NULL;
315:
316: p2->p_debugger = 0; /* don't inherit */
317: simple_lock_init(&p2->siglock);
318: p2->sigwait = FALSE;
319: p2->sigwait_thread = NULL;
320: p2->exit_thread = NULL;
321: p2->user_stack = p1->user_stack;
322:
323: #if KTRACE
324: /*
325: * Copy traceflag and tracefile if enabled.
326: * If not inherited, these were zeroed above.
327: */
328: if (p1->p_traceflag&KTRFAC_INHERIT) {
329: p2->p_traceflag = p1->p_traceflag;
330: if ((p2->p_tracep = p1->p_tracep) != NULL)
331: VREF(p2->p_tracep);
332: }
333: #endif
334:
335: th = procdup(p2, p1); /* child, parent */
336: LIST_INSERT_AFTER(p1, p2, p_pglist);
337: p2->p_pptr = p1;
338: LIST_INSERT_HEAD(&p1->p_children, p2, p_sibling);
339: LIST_INIT(&p2->p_children);
340: LIST_INSERT_HEAD(&allproc, p2, p_list);
341: LIST_INSERT_HEAD(PIDHASH(p2->p_pid), p2, p_hash);
342: TAILQ_INIT(&p2->p_evlist);
343: /*
344: * Make child runnable, set start time.
345: */
346: p2->p_stat = SRUN;
347:
348: return(th);
349: }
350:
351: struct zone *u_thread_zone;
352:
353: void
354: uzone_init()
355: {
356: u_thread_zone = zinit(sizeof(struct uthread),
357: THREAD_MAX * sizeof(struct uthread),
358: THREAD_CHUNK * sizeof(struct uthread),
359: "uthreads");
360: }
361:
362: void
363: uthread_free(uthread)
364: struct uthread *uthread;
365: {
366: zfree(u_thread_zone, (vm_offset_t) uthread);
367: }
368:
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