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1.1 root 1: /*
2: * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
3: *
4: * @APPLE_LICENSE_HEADER_START@
5: *
6: * Portions Copyright (c) 1999 Apple Computer, Inc. All Rights
7: * Reserved. This file contains Original Code and/or Modifications of
8: * Original Code as defined in and that are subject to the Apple Public
9: * Source License Version 1.1 (the "License"). You may not use this file
10: * except in compliance with the License. Please obtain a copy of the
11: * License at http://www.apple.com/publicsource and read it before using
12: * this file.
13: *
14: * The Original Code and all software distributed under the License are
15: * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
16: * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
17: * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
18: * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT. Please see the
19: * License for the specific language governing rights and limitations
20: * under the License.
21: *
22: * @APPLE_LICENSE_HEADER_END@
23: */
24:
25: /* Copyright (c) 1995, 1997 Apple Computer, Inc. All Rights Reserved */
26: /*
27: * Copyright (c) 1982, 1986, 1989, 1991, 1993
28: * The Regents of the University of California. All rights reserved.
29: * (c) UNIX System Laboratories, Inc.
30: * All or some portions of this file are derived from material licensed
31: * to the University of California by American Telephone and Telegraph
32: * Co. or Unix System Laboratories, Inc. and are reproduced herein with
33: * the permission of UNIX System Laboratories, Inc.
34: *
35: * Redistribution and use in source and binary forms, with or without
36: * modification, are permitted provided that the following conditions
37: * are met:
38: * 1. Redistributions of source code must retain the above copyright
39: * notice, this list of conditions and the following disclaimer.
40: * 2. Redistributions in binary form must reproduce the above copyright
41: * notice, this list of conditions and the following disclaimer in the
42: * documentation and/or other materials provided with the distribution.
43: * 3. All advertising materials mentioning features or use of this software
44: * must display the following acknowledgement:
45: * This product includes software developed by the University of
46: * California, Berkeley and its contributors.
47: * 4. Neither the name of the University nor the names of its contributors
48: * may be used to endorse or promote products derived from this software
49: * without specific prior written permission.
50: *
51: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
52: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
53: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
54: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
55: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
56: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
57: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
58: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
59: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
60: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
61: * SUCH DAMAGE.
62: *
63: * @(#)kern_fork.c 8.8 (Berkeley) 2/14/95
64: */
65:
66: #include <sys/param.h>
67: #include <sys/systm.h>
68: #include <sys/filedesc.h>
69: #include <sys/kernel.h>
70: #include <sys/malloc.h>
71: #include <sys/proc.h>
72: #include <sys/user.h>
73: #include <sys/resourcevar.h>
74: #include <sys/vnode.h>
75: #include <sys/file.h>
76: #include <sys/acct.h>
77: #include <sys/ktrace.h>
78:
79: #import <mach/mach_types.h>
80: #import <kern/mach_param.h>
81:
82: #import <machine/spl.h>
83:
84: thread_t cloneproc(), procdup();
85:
86: #define DOFORK 0x1 /* fork() system call */
87: #define DOVFORK 0x2 /* vfork() system call */
88: static int fork1(struct proc *, long, register_t *);
89:
90: /*
91: * fork system call.
92: */
93: int
94: fork(p, uap, retval)
95: struct proc *p;
96: void *uap;
97: register_t *retval;
98: {
99: return (fork1(p, (long)DOFORK, retval));
100: }
101:
102: /*
103: * vfork system call
104: */
105: int
106: vfork(p, uap, retval)
107: struct proc *p;
108: void *uap;
109: register_t *retval;
110: {
111: return (fork1(p, (long)DOVFORK, retval));
112: }
113:
114: static int
115: fork1(p1, flags, retval)
116: struct proc *p1;
117: long flags;
118: register_t *retval;
119: {
120: register struct proc *p2;
121: register uid_t uid;
122: thread_t newth, self = current_thread();
123: int s, count;
124:
125: /*
126: * Although process entries are dynamically created, we still keep
127: * a global limit on the maximum number we will create. Don't allow
128: * a nonprivileged user to use the last process; don't let root
129: * exceed the limit. The variable nprocs is the current number of
130: * processes, maxproc is the limit.
131: */
132: uid = p1->p_cred->p_ruid;
133: if ((nprocs >= maxproc - 1 && uid != 0) || nprocs >= maxproc) {
134: tablefull("proc");
135: retval[1] = 0;
136: return (EAGAIN);
137: }
138:
139: /*
140: * Increment the count of procs running with this uid. Don't allow
141: * a nonprivileged user to exceed their current limit.
142: */
143: count = chgproccnt(uid, 1);
144: if (uid != 0 && count > p1->p_rlimit[RLIMIT_NPROC].rlim_cur) {
145: (void)chgproccnt(uid, -1);
146: return (EAGAIN);
147: }
148:
149: newth = cloneproc(p1);
150: thread_dup(self, newth);
151: p2 = newth->task->proc;
152: s = splhigh();
153: p2->p_stats->p_start = time;
154: splx(s);
155: p2->p_acflag = AFORK;
156:
157: /*
158: * Preserve synchronization semantics of vfork. If waiting for
159: * child to exec or exit, set P_PPWAIT on child, and sleep on our
160: * proc (in case of exit).
161: */
162: if (flags == DOVFORK)
163: p2->p_flag |= P_PPWAIT;
164:
165: (void) thread_resume(newth);
166:
167: while (p2->p_flag & P_PPWAIT)
168: tsleep(p1, PWAIT, "ppwait", 0);
169:
170: retval[0] = p2->p_pid;
171: retval[1] = 0; /* mark parent */
172:
173: return (0);
174: }
175:
176: /*
177: * cloneproc()
178: *
179: * Create a new process from a specified process.
180: */
181: thread_t
182: cloneproc(p1)
183: register struct proc *p1;
184: {
185: register struct proc *p2, *newproc;
186: static int nextpid = 0, pidchecked = 0;
187: thread_t th;
188:
189: /* Allocate new proc. */
190: MALLOC_ZONE(newproc, struct proc *,
191: sizeof *newproc, M_PROC, M_WAITOK);
192: MALLOC_ZONE(newproc->p_cred, struct pcred *,
193: sizeof *newproc->p_cred, M_SUBPROC, M_WAITOK);
194: MALLOC_ZONE(newproc->p_stats, struct pstats *,
195: sizeof *newproc->p_stats, M_SUBPROC, M_WAITOK);
196: MALLOC_ZONE(newproc->p_sigacts, struct sigacts *,
197: sizeof *newproc->p_sigacts, M_SUBPROC, M_WAITOK);
198:
199: /*
200: * Find an unused process ID. We remember a range of unused IDs
201: * ready to use (from nextpid+1 through pidchecked-1).
202: */
203: nextpid++;
204: retry:
205: /*
206: * If the process ID prototype has wrapped around,
207: * restart somewhat above 0, as the low-numbered procs
208: * tend to include daemons that don't exit.
209: */
210: if (nextpid >= PID_MAX) {
211: nextpid = 100;
212: pidchecked = 0;
213: }
214: if (nextpid >= pidchecked) {
215: int doingzomb = 0;
216:
217: pidchecked = PID_MAX;
218: /*
219: * Scan the active and zombie procs to check whether this pid
220: * is in use. Remember the lowest pid that's greater
221: * than nextpid, so we can avoid checking for a while.
222: */
223: p2 = allproc.lh_first;
224: again:
225: for (; p2 != 0; p2 = p2->p_list.le_next) {
226: while (p2->p_pid == nextpid ||
227: p2->p_pgrp->pg_id == nextpid) {
228: nextpid++;
229: if (nextpid >= pidchecked)
230: goto retry;
231: }
232: if (p2->p_pid > nextpid && pidchecked > p2->p_pid)
233: pidchecked = p2->p_pid;
234: if (p2->p_pgrp->pg_id > nextpid &&
235: pidchecked > p2->p_pgrp->pg_id)
236: pidchecked = p2->p_pgrp->pg_id;
237: }
238: if (!doingzomb) {
239: doingzomb = 1;
240: p2 = zombproc.lh_first;
241: goto again;
242: }
243: }
244:
245: nprocs++;
246: p2 = newproc;
247: p2->p_stat = SIDL;
248: p2->p_pid = nextpid;
249:
250: /*
251: * Make a proc table entry for the new process.
252: * Start by zeroing the section of proc that is zero-initialized,
253: * then copy the section that is copied directly from the parent.
254: */
255: bzero(&p2->p_startzero,
256: (unsigned) ((caddr_t)&p2->p_endzero - (caddr_t)&p2->p_startzero));
257: bcopy(&p1->p_startcopy, &p2->p_startcopy,
258: (unsigned) ((caddr_t)&p2->p_endcopy - (caddr_t)&p2->p_startcopy));
259:
260: /*
261: * Duplicate sub-structures as needed.
262: * Increase reference counts on shared objects.
263: * The p_stats and p_sigacts substructs are set in vm_fork.
264: */
265: p2->p_flag = P_INMEM;
266: if (p1->p_flag & P_PROFIL)
267: startprofclock(p2);
268: bcopy(p1->p_cred, p2->p_cred, sizeof(*p2->p_cred));
269: p2->p_cred->p_refcnt = 1;
270: crhold(p1->p_ucred);
271: lockinit(&p2->p_cred->pc_lock, PLOCK, "proc cred", 0, 0);
272:
273: /* bump references to the text vnode (for procfs) */
274: p2->p_textvp = p1->p_textvp;
275: if (p2->p_textvp)
276: VREF(p2->p_textvp);
277:
278: p2->p_fd = fdcopy(p1);
279: /*
280: * If p_limit is still copy-on-write, bump refcnt,
281: * otherwise get a copy that won't be modified.
282: * (If PL_SHAREMOD is clear, the structure is shared
283: * copy-on-write.)
284: */
285: if (p1->p_limit->p_lflags & PL_SHAREMOD)
286: p2->p_limit = limcopy(p1->p_limit);
287: else {
288: p2->p_limit = p1->p_limit;
289: p2->p_limit->p_refcnt++;
290: }
291:
292: bzero(&p2->p_stats->pstat_startzero,
293: (unsigned) ((caddr_t)&p2->p_stats->pstat_endzero -
294: (caddr_t)&p2->p_stats->pstat_startzero));
295: bcopy(&p1->p_stats->pstat_startcopy, &p2->p_stats->pstat_startcopy,
296: ((caddr_t)&p2->p_stats->pstat_endcopy -
297: (caddr_t)&p2->p_stats->pstat_startcopy));
298:
299: if (p1->p_sigacts != NULL)
300: (void)memcpy(p2->p_sigacts,
301: p1->p_sigacts, sizeof *p2->p_sigacts);
302: else
303: (void)memset(p2->p_sigacts, 0, sizeof *p2->p_sigacts);
304:
305: if (p1->p_session->s_ttyvp != NULL && p1->p_flag & P_CONTROLT)
306: p2->p_flag |= P_CONTROLT;
307:
308: p2->p_xstat = 0;
309: p2->p_ru = NULL;
310:
311: p2->p_debugger = 0; /* don't inherit */
312: simple_lock_init(&p2->siglock);
313: p2->sigwait = FALSE;
314: p2->sigwait_thread = NULL;
315: p2->exit_thread = NULL;
316: p2->user_stack = p1->user_stack;
317:
318: #if KTRACE
319: /*
320: * Copy traceflag and tracefile if enabled.
321: * If not inherited, these were zeroed above.
322: */
323: if (p1->p_traceflag&KTRFAC_INHERIT) {
324: p2->p_traceflag = p1->p_traceflag;
325: if ((p2->p_tracep = p1->p_tracep) != NULL)
326: VREF(p2->p_tracep);
327: }
328: #endif
329:
330: th = procdup(p2, p1); /* child, parent */
331: LIST_INSERT_AFTER(p1, p2, p_pglist);
332: p2->p_pptr = p1;
333: LIST_INSERT_HEAD(&p1->p_children, p2, p_sibling);
334: LIST_INIT(&p2->p_children);
335: LIST_INSERT_HEAD(&allproc, p2, p_list);
336: LIST_INSERT_HEAD(PIDHASH(p2->p_pid), p2, p_hash);
337: TAILQ_INIT(&p2->p_evlist);
338: /*
339: * Make child runnable, set start time.
340: */
341: p2->p_stat = SRUN;
342:
343: return(th);
344: }
345:
346: struct zone *u_thread_zone;
347:
348: void
349: uzone_init()
350: {
351: u_thread_zone = zinit(sizeof(struct uthread),
352: THREAD_MAX * sizeof(struct uthread),
353: THREAD_CHUNK * sizeof(struct uthread),
354: FALSE, "uthreads");
355: }
356:
357: void
358: uthread_free(uthread)
359: struct uthread *uthread;
360: {
361: zfree(u_thread_zone, (vm_offset_t) uthread);
362: }
363:
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