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25 /* Copyright (c) 1995, 1997 Apple Computer, Inc. All Rights Reserved */
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29 * (c) UNIX System Laboratories, Inc.
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63 * @(#)kern_fork.c 8.8 (Berkeley) 2/14/95
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>
73 #include <sys/resourcevar.h>
74 #include <sys/vnode.h>
78 #include <sys/ktrace.h>
81 #include <mach/mach_types.h>
82 #include <kern/mach_param.h>
84 #include <machine/spl.h>
86 thread_act_t
cloneproc(struct proc
*, int);
87 struct proc
* forkproc(struct proc
*, int);
88 thread_act_t
procdup();
90 #define DOFORK 0x1 /* fork() system call */
91 #define DOVFORK 0x2 /* vfork() system call */
92 static int fork1(struct proc
*, long, register_t
*);
103 return (fork1(p
, (long)DOFORK
, retval
));
110 vfork(p
, uap
, retval
)
115 register struct proc
* newproc
;
117 thread_act_t cur_act
= (thread_act_t
)current_act();
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.
129 uid
= p
->p_cred
->p_ruid
;
130 if ((nprocs
>= maxproc
- 1 && uid
!= 0) || nprocs
>= maxproc
) {
137 * Increment the count of procs running with this uid. Don't allow
138 * a nonprivileged user to exceed their current limit.
140 count
= chgproccnt(uid
, 1);
141 if (uid
!= 0 && count
> p
->p_rlimit
[RLIMIT_NPROC
].rlim_cur
) {
142 (void)chgproccnt(uid
, -1);
146 ut
= (struct uthread
*)get_bsdthread_info(cur_act
);
147 if (ut
->uu_flag
& P_VFORK
) {
148 printf("vfork called recursively by %s\n", p
->p_comm
);
151 p
->p_flag
|= P_VFORK
;
154 /* The newly created process comes with signal lock held */
155 newproc
= (struct proc
*)forkproc(p
,1);
157 LIST_INSERT_AFTER(p
, newproc
, p_pglist
);
159 newproc
->task
= p
->task
;
160 LIST_INSERT_HEAD(&p
->p_children
, newproc
, p_sibling
);
161 LIST_INIT(&newproc
->p_children
);
162 LIST_INSERT_HEAD(&allproc
, newproc
, p_list
);
163 LIST_INSERT_HEAD(PIDHASH(newproc
->p_pid
), newproc
, p_hash
);
164 TAILQ_INIT(& newproc
->p_evlist
);
165 newproc
->p_stat
= SRUN
;
166 newproc
->p_flag
|= P_INVFORK
;
167 newproc
->p_vforkact
= cur_act
;
169 ut
->uu_flag
|= P_VFORK
;
170 ut
->uu_proc
= newproc
;
171 ut
->uu_userstate
= (void *)act_thread_csave();
172 ut
->uu_vforkmask
= ut
->uu_sigmask
;
174 thread_set_child(cur_act
, newproc
->p_pid
);
176 newproc
->p_stats
->p_start
= time
;
177 newproc
->p_acflag
= AFORK
;
180 * Preserve synchronization semantics of vfork. If waiting for
181 * child to exec or exit, set P_PPWAIT on child, and sleep on our
182 * proc (in case of exit).
184 newproc
->p_flag
|= P_PPWAIT
;
186 /* drop the signal lock on the child */
187 signal_unlock(newproc
);
189 retval
[0] = newproc
->p_pid
;
190 retval
[1] = 1; /* mark child */
196 * Return to parent vfork ehread()
199 vfork_return(th_act
, p
, p2
, retval
)
207 thread_t newth
, self
= current_thread();
208 thread_act_t cur_act
= (thread_act_t
)current_act();
213 ut
= (struct uthread
*)get_bsdthread_info(cur_act
);
215 act_thread_catt(ut
->uu_userstate
);
217 /* Make sure only one at this time */
219 if (p
->p_vforkcnt
<0)
220 panic("vfork cnt is -ve");
221 if (p
->p_vforkcnt
<=0)
222 p
->p_flag
&= ~P_VFORK
;
223 ut
->uu_userstate
= 0;
224 ut
->uu_flag
&= ~P_VFORK
;
226 ut
->uu_sigmask
= ut
->uu_vforkmask
;
227 p2
->p_flag
&= ~P_INVFORK
;
228 p2
->p_vforkact
= (void *)0;
230 thread_set_parent(cur_act
, p2
->p_pid
);
233 retval
[0] = p2
->p_pid
;
234 retval
[1] = 0; /* mark parent */
247 kern_return_t result
;
248 extern task_t kernel_task
;
250 if (parent
->task
== kernel_task
)
251 result
= task_create_local(TASK_NULL
, FALSE
, FALSE
, &task
);
253 result
= task_create_local(parent
->task
, TRUE
, FALSE
, &task
);
254 if (result
!= KERN_SUCCESS
)
255 printf("fork/procdup: task_create failed. Code: 0x%x\n", result
);
257 /* task->proc = child; */
258 set_bsdtask_info(task
, child
);
259 if (child
->p_nice
!= 0)
260 resetpriority(child
);
261 result
= thread_create(task
, &thread
);
262 if (result
!= KERN_SUCCESS
)
263 printf("fork/procdup: thread_create failed. Code: 0x%x\n", result
);
270 fork1(p1
, flags
, retval
)
275 register struct proc
*p2
;
282 * Although process entries are dynamically created, we still keep
283 * a global limit on the maximum number we will create. Don't allow
284 * a nonprivileged user to use the last process; don't let root
285 * exceed the limit. The variable nprocs is the current number of
286 * processes, maxproc is the limit.
288 uid
= p1
->p_cred
->p_ruid
;
289 if ((nprocs
>= maxproc
- 1 && uid
!= 0) || nprocs
>= maxproc
) {
296 * Increment the count of procs running with this uid. Don't allow
297 * a nonprivileged user to exceed their current limit.
299 count
= chgproccnt(uid
, 1);
300 if (uid
!= 0 && count
> p1
->p_rlimit
[RLIMIT_NPROC
].rlim_cur
) {
301 (void)chgproccnt(uid
, -1);
305 /* The newly created process comes with signal lock held */
306 newth
= cloneproc(p1
, 1);
308 /* p2 = newth->task->proc; */
309 p2
= (struct proc
*)(get_bsdtask_info(get_threadtask(newth
)));
311 thread_set_child(newth
, p2
->p_pid
);
314 p2
->p_stats
->p_start
= time
;
316 p2
->p_acflag
= AFORK
;
319 * Preserve synchronization semantics of vfork. If waiting for
320 * child to exec or exit, set P_PPWAIT on child, and sleep on our
321 * proc (in case of exit).
323 if (flags
== DOVFORK
)
324 p2
->p_flag
|= P_PPWAIT
;
325 /* drop the signal lock on the child */
328 (void) thread_resume(newth
);
330 /* drop the extra references we got during the creation */
331 if (t
= (task_t
)get_threadtask(newth
)) {
334 act_deallocate(newth
);
336 while (p2
->p_flag
& P_PPWAIT
)
337 tsleep(p1
, PWAIT
, "ppwait", 0);
339 retval
[0] = p2
->p_pid
;
340 retval
[1] = 0; /* mark parent */
348 * Create a new process from a specified process.
349 * On return newly created child process has signal
350 * lock held to block delivery of signal to it if called with
351 * lock set. fork() code needs to explicity remove this lock
352 * before signals can be delivered
356 register struct proc
*p1
;
359 register struct proc
*p2
;
362 p2
= (struct proc
*)forkproc(p1
,lock
);
365 th
= procdup(p2
, p1
); /* child, parent */
367 LIST_INSERT_AFTER(p1
, p2
, p_pglist
);
369 LIST_INSERT_HEAD(&p1
->p_children
, p2
, p_sibling
);
370 LIST_INIT(&p2
->p_children
);
371 LIST_INSERT_HEAD(&allproc
, p2
, p_list
);
372 LIST_INSERT_HEAD(PIDHASH(p2
->p_pid
), p2
, p_hash
);
373 TAILQ_INIT(&p2
->p_evlist
);
375 * Make child runnable, set start time.
384 register struct proc
*p1
;
387 register struct proc
*p2
, *newproc
;
388 static int nextpid
= 0, pidchecked
= 0;
391 /* Allocate new proc. */
392 MALLOC_ZONE(newproc
, struct proc
*,
393 sizeof *newproc
, M_PROC
, M_WAITOK
);
394 MALLOC_ZONE(newproc
->p_cred
, struct pcred
*,
395 sizeof *newproc
->p_cred
, M_SUBPROC
, M_WAITOK
);
396 MALLOC_ZONE(newproc
->p_stats
, struct pstats
*,
397 sizeof *newproc
->p_stats
, M_SUBPROC
, M_WAITOK
);
398 MALLOC_ZONE(newproc
->p_sigacts
, struct sigacts
*,
399 sizeof *newproc
->p_sigacts
, M_SUBPROC
, M_WAITOK
);
402 * Find an unused process ID. We remember a range of unused IDs
403 * ready to use (from nextpid+1 through pidchecked-1).
408 * If the process ID prototype has wrapped around,
409 * restart somewhat above 0, as the low-numbered procs
410 * tend to include daemons that don't exit.
412 if (nextpid
>= PID_MAX
) {
416 if (nextpid
>= pidchecked
) {
419 pidchecked
= PID_MAX
;
421 * Scan the active and zombie procs to check whether this pid
422 * is in use. Remember the lowest pid that's greater
423 * than nextpid, so we can avoid checking for a while.
425 p2
= allproc
.lh_first
;
427 for (; p2
!= 0; p2
= p2
->p_list
.le_next
) {
428 while (p2
->p_pid
== nextpid
||
429 p2
->p_pgrp
->pg_id
== nextpid
||
430 p2
->p_session
->s_sid
== nextpid
) {
432 if (nextpid
>= pidchecked
)
435 if (p2
->p_pid
> nextpid
&& pidchecked
> p2
->p_pid
)
436 pidchecked
= p2
->p_pid
;
437 if (p2
->p_pgrp
&& p2
->p_pgrp
->pg_id
> nextpid
&&
438 pidchecked
> p2
->p_pgrp
->pg_id
)
439 pidchecked
= p2
->p_pgrp
->pg_id
;
440 if (p2
->p_session
->s_sid
> nextpid
&&
441 pidchecked
> p2
->p_session
->s_sid
)
442 pidchecked
= p2
->p_session
->s_sid
;
446 p2
= zombproc
.lh_first
;
457 * Make a proc table entry for the new process.
458 * Start by zeroing the section of proc that is zero-initialized,
459 * then copy the section that is copied directly from the parent.
461 bzero(&p2
->p_startzero
,
462 (unsigned) ((caddr_t
)&p2
->p_endzero
- (caddr_t
)&p2
->p_startzero
));
463 bcopy(&p1
->p_startcopy
, &p2
->p_startcopy
,
464 (unsigned) ((caddr_t
)&p2
->p_endcopy
- (caddr_t
)&p2
->p_startcopy
));
465 p2
->vm_shm
= (void *)NULL
; /* Make sure it is zero */
468 * Duplicate sub-structures as needed.
469 * Increase reference counts on shared objects.
470 * The p_stats and p_sigacts substructs are set in vm_fork.
472 p2
->p_flag
= P_INMEM
;
473 if (p1
->p_flag
& P_PROFIL
)
475 bcopy(p1
->p_cred
, p2
->p_cred
, sizeof(*p2
->p_cred
));
476 p2
->p_cred
->p_refcnt
= 1;
478 lockinit(&p2
->p_cred
->pc_lock
, PLOCK
, "proc cred", 0, 0);
480 /* bump references to the text vnode */
481 p2
->p_textvp
= p1
->p_textvp
;
485 p2
->p_fd
= fdcopy(p1
);
490 * If p_limit is still copy-on-write, bump refcnt,
491 * otherwise get a copy that won't be modified.
492 * (If PL_SHAREMOD is clear, the structure is shared
495 if (p1
->p_limit
->p_lflags
& PL_SHAREMOD
)
496 p2
->p_limit
= limcopy(p1
->p_limit
);
498 p2
->p_limit
= p1
->p_limit
;
499 p2
->p_limit
->p_refcnt
++;
502 bzero(&p2
->p_stats
->pstat_startzero
,
503 (unsigned) ((caddr_t
)&p2
->p_stats
->pstat_endzero
-
504 (caddr_t
)&p2
->p_stats
->pstat_startzero
));
505 bcopy(&p1
->p_stats
->pstat_startcopy
, &p2
->p_stats
->pstat_startcopy
,
506 ((caddr_t
)&p2
->p_stats
->pstat_endcopy
-
507 (caddr_t
)&p2
->p_stats
->pstat_startcopy
));
509 if (p1
->p_sigacts
!= NULL
)
510 (void)memcpy(p2
->p_sigacts
,
511 p1
->p_sigacts
, sizeof *p2
->p_sigacts
);
513 (void)memset(p2
->p_sigacts
, 0, sizeof *p2
->p_sigacts
);
515 if (p1
->p_session
->s_ttyvp
!= NULL
&& p1
->p_flag
& P_CONTROLT
)
516 p2
->p_flag
|= P_CONTROLT
;
521 p2
->p_debugger
= 0; /* don't inherit */
522 lockinit(&p2
->signal_lock
, PVM
, "signal", 0, 0);
523 /* block all signals to reach the process */
527 p2
->sigwait_thread
= NULL
;
528 p2
->exit_thread
= NULL
;
529 p2
->user_stack
= p1
->user_stack
;
530 p2
->p_xxxsigpending
= 0;
533 TAILQ_INIT(&p2
->p_uthlist
);
537 * Copy traceflag and tracefile if enabled.
538 * If not inherited, these were zeroed above.
540 if (p1
->p_traceflag
&KTRFAC_INHERIT
) {
541 p2
->p_traceflag
= p1
->p_traceflag
;
542 if ((p2
->p_tracep
= p1
->p_tracep
) != NULL
)
550 #include <kern/zalloc.h>
552 struct zone
*uthread_zone
;
553 int uthread_zone_inited
= 0;
558 if (!uthread_zone_inited
) {
559 uthread_zone
= zinit(sizeof(struct uthread
),
560 THREAD_MAX
* sizeof(struct uthread
),
561 THREAD_CHUNK
* sizeof(struct uthread
),
563 uthread_zone_inited
= 1;
568 uthread_alloc(task_t task
, thread_act_t thr_act
)
571 struct uthread
*uth
, *uth_parent
;
573 extern task_t kernel_task
;
574 boolean_t funnel_state
;
576 if (!uthread_zone_inited
)
579 ut
= (void *)zalloc(uthread_zone
);
580 bzero(ut
, sizeof(struct uthread
));
582 if (task
!= kernel_task
) {
583 uth
= (struct uthread
*)ut
;
584 p
= get_bsdtask_info(task
);
586 funnel_state
= thread_funnel_set(kernel_flock
, TRUE
);
587 uth_parent
= (struct uthread
*)get_bsdthread_info(current_act());
589 if (uth_parent
->uu_flag
& USAS_OLDMASK
)
590 uth
->uu_sigmask
= uth_parent
->uu_oldmask
;
592 uth
->uu_sigmask
= uth_parent
->uu_sigmask
;
594 uth
->uu_act
= thr_act
;
597 TAILQ_INSERT_TAIL(&p
->p_uthlist
, uth
, uu_list
);
599 (void)thread_funnel_set(kernel_flock
, funnel_state
);
607 uthread_free(task_t task
, void *uthread
, void * bsd_info
)
610 struct uthread
*uth
= (struct uthread
*)uthread
;
611 struct proc
* p
= (struct proc
*)bsd_info
;
612 extern task_t kernel_task
;
614 boolean_t funnel_state
;
616 sel
= &uth
->uu_state
.ss_select
;
617 /* cleanup the select bit space */
619 FREE(sel
->ibits
, M_TEMP
);
620 FREE(sel
->obits
, M_TEMP
);
623 if (sel
->allocsize
&& uth
->uu_wqsub
){
624 kfree(uth
->uu_wqsub
, sel
->allocsize
);
625 sel
->count
= sel
->nfcount
= 0;
631 if ((task
!= kernel_task
) && p
) {
632 funnel_state
= thread_funnel_set(kernel_flock
, TRUE
);
634 TAILQ_REMOVE(&p
->p_uthlist
, uth
, uu_list
);
636 (void)thread_funnel_set(kernel_flock
, funnel_state
);
638 /* and free the uthread itself */
639 zfree(uthread_zone
, (vm_offset_t
)uthread
);