xref: /freebsd/sys/compat/linux/linux_fork.c (revision 3fc36ee018bb836bd1796067cf4ef8683f166ebc) 
1 /*-
2  * Copyright (c) 2004 Tim J. Robbins
3  * Copyright (c) 2002 Doug Rabson
4  * Copyright (c) 2000 Marcel Moolenaar
5  * All rights reserved.
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  * 1. Redistributions of source code must retain the above copyright
11  *    notice, this list of conditions and the following disclaimer
12  *    in this position and unchanged.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in the
15  *    documentation and/or other materials provided with the distribution.
16  *
17  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27  */
28 
29 #include <sys/cdefs.h>
30 __FBSDID("$FreeBSD$");
31 
32 #include "opt_compat.h"
33 
34 #include <sys/param.h>
35 #include <sys/systm.h>
36 #include <sys/imgact.h>
37 #include <sys/ktr.h>
38 #include <sys/lock.h>
39 #include <sys/mutex.h>
40 #include <sys/proc.h>
41 #include <sys/racct.h>
42 #include <sys/sched.h>
43 #include <sys/syscallsubr.h>
44 #include <sys/sx.h>
45 #include <sys/umtx.h>
46 #include <sys/unistd.h>
47 #include <sys/wait.h>
48 
49 #include <vm/vm.h>
50 #include <vm/pmap.h>
51 #include <vm/vm_map.h>
52 
53 #ifdef COMPAT_LINUX32
54 #include <machine/../linux32/linux.h>
55 #include <machine/../linux32/linux32_proto.h>
56 #else
57 #include <machine/../linux/linux.h>
58 #include <machine/../linux/linux_proto.h>
59 #endif
60 #include <compat/linux/linux_emul.h>
61 #include <compat/linux/linux_futex.h>
62 #include <compat/linux/linux_misc.h>
63 #include <compat/linux/linux_util.h>
64 
65 int
66 linux_fork(struct thread *td, struct linux_fork_args *args)
67 {
68 	struct fork_req fr;
69 	int error;
70 	struct proc *p2;
71 	struct thread *td2;
72 
73 #ifdef DEBUG
74 	if (ldebug(fork))
75 		printf(ARGS(fork, ""));
76 #endif
77 
78 	bzero(&fr, sizeof(fr));
79 	fr.fr_flags = RFFDG | RFPROC | RFSTOPPED;
80 	fr.fr_procp = &p2;
81 	if ((error = fork1(td, &fr)) != 0)
82 		return (error);
83 
84 	td2 = FIRST_THREAD_IN_PROC(p2);
85 
86 	linux_proc_init(td, td2, 0);
87 
88 	td->td_retval[0] = p2->p_pid;
89 
90 	/*
91 	 * Make this runnable after we are finished with it.
92 	 */
93 	thread_lock(td2);
94 	TD_SET_CAN_RUN(td2);
95 	sched_add(td2, SRQ_BORING);
96 	thread_unlock(td2);
97 
98 	return (0);
99 }
100 
101 int
102 linux_vfork(struct thread *td, struct linux_vfork_args *args)
103 {
104 	struct fork_req fr;
105 	int error;
106 	struct proc *p2;
107 	struct thread *td2;
108 
109 #ifdef DEBUG
110 	if (ldebug(vfork))
111 		printf(ARGS(vfork, ""));
112 #endif
113 
114 	bzero(&fr, sizeof(fr));
115 	fr.fr_flags = RFFDG | RFPROC | RFMEM | RFPPWAIT | RFSTOPPED;
116 	fr.fr_procp = &p2;
117 	if ((error = fork1(td, &fr)) != 0)
118 		return (error);
119 
120 	td2 = FIRST_THREAD_IN_PROC(p2);
121 
122 	linux_proc_init(td, td2, 0);
123 
124    	td->td_retval[0] = p2->p_pid;
125 
126 	/*
127 	 * Make this runnable after we are finished with it.
128 	 */
129 	thread_lock(td2);
130 	TD_SET_CAN_RUN(td2);
131 	sched_add(td2, SRQ_BORING);
132 	thread_unlock(td2);
133 
134 	return (0);
135 }
136 
137 static int
138 linux_clone_proc(struct thread *td, struct linux_clone_args *args)
139 {
140 	struct fork_req fr;
141 	int error, ff = RFPROC | RFSTOPPED;
142 	struct proc *p2;
143 	struct thread *td2;
144 	int exit_signal;
145 	struct linux_emuldata *em;
146 
147 #ifdef DEBUG
148 	if (ldebug(clone)) {
149 		printf(ARGS(clone, "flags %x, stack %p, parent tid: %p, "
150 		    "child tid: %p"), (unsigned)args->flags,
151 		    args->stack, args->parent_tidptr, args->child_tidptr);
152 	}
153 #endif
154 
155 	exit_signal = args->flags & 0x000000ff;
156 	if (LINUX_SIG_VALID(exit_signal)) {
157 		exit_signal = linux_to_bsd_signal(exit_signal);
158 	} else if (exit_signal != 0)
159 		return (EINVAL);
160 
161 	if (args->flags & LINUX_CLONE_VM)
162 		ff |= RFMEM;
163 	if (args->flags & LINUX_CLONE_SIGHAND)
164 		ff |= RFSIGSHARE;
165 	/*
166 	 * XXX: In Linux, sharing of fs info (chroot/cwd/umask)
167 	 * and open files is independent.  In FreeBSD, its in one
168 	 * structure but in reality it does not cause any problems
169 	 * because both of these flags are usually set together.
170 	 */
171 	if (!(args->flags & (LINUX_CLONE_FILES | LINUX_CLONE_FS)))
172 		ff |= RFFDG;
173 
174 	if (args->flags & LINUX_CLONE_PARENT_SETTID)
175 		if (args->parent_tidptr == NULL)
176 			return (EINVAL);
177 
178 	if (args->flags & LINUX_CLONE_VFORK)
179 		ff |= RFPPWAIT;
180 
181 	bzero(&fr, sizeof(fr));
182 	fr.fr_flags = ff;
183 	fr.fr_procp = &p2;
184 	error = fork1(td, &fr);
185 	if (error)
186 		return (error);
187 
188 	td2 = FIRST_THREAD_IN_PROC(p2);
189 
190 	/* create the emuldata */
191 	linux_proc_init(td, td2, args->flags);
192 
193 	em = em_find(td2);
194 	KASSERT(em != NULL, ("clone_proc: emuldata not found.\n"));
195 
196 	if (args->flags & LINUX_CLONE_CHILD_SETTID)
197 		em->child_set_tid = args->child_tidptr;
198 	else
199 	   	em->child_set_tid = NULL;
200 
201 	if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
202 		em->child_clear_tid = args->child_tidptr;
203 	else
204 	   	em->child_clear_tid = NULL;
205 
206 	if (args->flags & LINUX_CLONE_PARENT_SETTID) {
207 		error = copyout(&p2->p_pid, args->parent_tidptr,
208 		    sizeof(p2->p_pid));
209 		if (error)
210 			printf(LMSG("copyout failed!"));
211 	}
212 
213 	PROC_LOCK(p2);
214 	p2->p_sigparent = exit_signal;
215 	PROC_UNLOCK(p2);
216 	/*
217 	 * In a case of stack = NULL, we are supposed to COW calling process
218 	 * stack. This is what normal fork() does, so we just keep tf_rsp arg
219 	 * intact.
220 	 */
221 	linux_set_upcall_kse(td2, PTROUT(args->stack));
222 
223 	if (args->flags & LINUX_CLONE_SETTLS)
224 		linux_set_cloned_tls(td2, args->tls);
225 
226 	/*
227 	 * If CLONE_PARENT is set, then the parent of the new process will be
228 	 * the same as that of the calling process.
229 	 */
230 	if (args->flags & LINUX_CLONE_PARENT) {
231 		sx_xlock(&proctree_lock);
232 		PROC_LOCK(p2);
233 		proc_reparent(p2, td->td_proc->p_pptr);
234 		PROC_UNLOCK(p2);
235 		sx_xunlock(&proctree_lock);
236 	}
237 
238 #ifdef DEBUG
239 	if (ldebug(clone))
240 		printf(LMSG("clone: successful rfork to %d, "
241 		    "stack %p sig = %d"), (int)p2->p_pid, args->stack,
242 		    exit_signal);
243 #endif
244 
245 	/*
246 	 * Make this runnable after we are finished with it.
247 	 */
248 	thread_lock(td2);
249 	TD_SET_CAN_RUN(td2);
250 	sched_add(td2, SRQ_BORING);
251 	thread_unlock(td2);
252 
253 	td->td_retval[0] = p2->p_pid;
254 
255 	return (0);
256 }
257 
258 static int
259 linux_clone_thread(struct thread *td, struct linux_clone_args *args)
260 {
261 	struct linux_emuldata *em;
262 	struct thread *newtd;
263 	struct proc *p;
264 	int error;
265 
266 #ifdef DEBUG
267 	if (ldebug(clone)) {
268 		printf(ARGS(clone, "thread: flags %x, stack %p, parent tid: %p, "
269 		    "child tid: %p"), (unsigned)args->flags,
270 		    args->stack, args->parent_tidptr, args->child_tidptr);
271 	}
272 #endif
273 
274 	LINUX_CTR4(clone_thread, "thread(%d) flags %x ptid %p ctid %p",
275 	    td->td_tid, (unsigned)args->flags,
276 	    args->parent_tidptr, args->child_tidptr);
277 
278 	if (args->flags & LINUX_CLONE_PARENT_SETTID)
279 		if (args->parent_tidptr == NULL)
280 			return (EINVAL);
281 
282 	/* Threads should be created with own stack */
283 	if (args->stack == NULL)
284 		return (EINVAL);
285 
286 	p = td->td_proc;
287 
288 #ifdef RACCT
289 	if (racct_enable) {
290 		PROC_LOCK(p);
291 		error = racct_add(p, RACCT_NTHR, 1);
292 		PROC_UNLOCK(p);
293 		if (error != 0)
294 			return (EPROCLIM);
295 	}
296 #endif
297 
298 	/* Initialize our td */
299 	error = kern_thr_alloc(p, 0, &newtd);
300 	if (error)
301 		goto fail;
302 
303 	cpu_copy_thread(newtd, td);
304 
305 	bzero(&newtd->td_startzero,
306 	    __rangeof(struct thread, td_startzero, td_endzero));
307 	bcopy(&td->td_startcopy, &newtd->td_startcopy,
308 	    __rangeof(struct thread, td_startcopy, td_endcopy));
309 
310 	newtd->td_proc = p;
311 	thread_cow_get(newtd, td);
312 
313 	/* create the emuldata */
314 	linux_proc_init(td, newtd, args->flags);
315 
316 	em = em_find(newtd);
317 	KASSERT(em != NULL, ("clone_thread: emuldata not found.\n"));
318 
319 	if (args->flags & LINUX_CLONE_SETTLS)
320 		linux_set_cloned_tls(newtd, args->tls);
321 
322 	if (args->flags & LINUX_CLONE_CHILD_SETTID)
323 		em->child_set_tid = args->child_tidptr;
324 	else
325 	   	em->child_set_tid = NULL;
326 
327 	if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
328 		em->child_clear_tid = args->child_tidptr;
329 	else
330 	   	em->child_clear_tid = NULL;
331 
332 	cpu_thread_clean(newtd);
333 
334 	linux_set_upcall_kse(newtd, PTROUT(args->stack));
335 
336 	PROC_LOCK(p);
337 	p->p_flag |= P_HADTHREADS;
338 	bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
339 
340 	if (args->flags & LINUX_CLONE_PARENT)
341 		thread_link(newtd, p->p_pptr);
342 	else
343 		thread_link(newtd, p);
344 
345 	thread_lock(td);
346 	/* let the scheduler know about these things. */
347 	sched_fork_thread(td, newtd);
348 	thread_unlock(td);
349 	if (P_SHOULDSTOP(p))
350 		newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
351 	PROC_UNLOCK(p);
352 
353 	tidhash_add(newtd);
354 
355 #ifdef DEBUG
356 	if (ldebug(clone))
357 		printf(ARGS(clone, "successful clone to %d, stack %p"),
358 		(int)newtd->td_tid, args->stack);
359 #endif
360 
361 	LINUX_CTR2(clone_thread, "thread(%d) successful clone to %d",
362 	    td->td_tid, newtd->td_tid);
363 
364 	if (args->flags & LINUX_CLONE_PARENT_SETTID) {
365 		error = copyout(&newtd->td_tid, args->parent_tidptr,
366 		    sizeof(newtd->td_tid));
367 		if (error)
368 			printf(LMSG("clone_thread: copyout failed!"));
369 	}
370 
371 	/*
372 	 * Make this runnable after we are finished with it.
373 	 */
374 	thread_lock(newtd);
375 	TD_SET_CAN_RUN(newtd);
376 	sched_add(newtd, SRQ_BORING);
377 	thread_unlock(newtd);
378 
379 	td->td_retval[0] = newtd->td_tid;
380 
381 	return (0);
382 
383 fail:
384 #ifdef RACCT
385 	if (racct_enable) {
386 		PROC_LOCK(p);
387 		racct_sub(p, RACCT_NTHR, 1);
388 		PROC_UNLOCK(p);
389 	}
390 #endif
391 	return (error);
392 }
393 
394 int
395 linux_clone(struct thread *td, struct linux_clone_args *args)
396 {
397 
398 	if (args->flags & LINUX_CLONE_THREAD)
399 		return (linux_clone_thread(td, args));
400 	else
401 		return (linux_clone_proc(td, args));
402 }
403 
404 int
405 linux_exit(struct thread *td, struct linux_exit_args *args)
406 {
407 	struct linux_emuldata *em;
408 
409 	em = em_find(td);
410 	KASSERT(em != NULL, ("exit: emuldata not found.\n"));
411 
412 	LINUX_CTR2(exit, "thread(%d) (%d)", em->em_tid, args->rval);
413 
414 	umtx_thread_exit(td);
415 
416 	linux_thread_detach(td);
417 
418 	/*
419 	 * XXX. When the last two threads of a process
420 	 * exit via pthread_exit() try thr_exit() first.
421 	 */
422 	kern_thr_exit(td);
423 	exit1(td, args->rval, 0);
424 		/* NOTREACHED */
425 }
426 
427 int
428 linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args)
429 {
430 	struct linux_emuldata *em;
431 
432 	em = em_find(td);
433 	KASSERT(em != NULL, ("set_tid_address: emuldata not found.\n"));
434 
435 	em->child_clear_tid = args->tidptr;
436 
437 	td->td_retval[0] = em->em_tid;
438 
439 	LINUX_CTR3(set_tid_address, "tidptr(%d) %p, returns %d",
440 	    em->em_tid, args->tidptr, td->td_retval[0]);
441 
442 	return (0);
443 }
444 
445 void
446 linux_thread_detach(struct thread *td)
447 {
448 	struct linux_sys_futex_args cup;
449 	struct linux_emuldata *em;
450 	int *child_clear_tid;
451 	int error;
452 
453 	em = em_find(td);
454 	KASSERT(em != NULL, ("thread_detach: emuldata not found.\n"));
455 
456 	LINUX_CTR1(thread_detach, "thread(%d)", em->em_tid);
457 
458 	release_futexes(td, em);
459 
460 	child_clear_tid = em->child_clear_tid;
461 
462 	if (child_clear_tid != NULL) {
463 
464 		LINUX_CTR2(thread_detach, "thread(%d) %p",
465 		    em->em_tid, child_clear_tid);
466 
467 		error = suword32(child_clear_tid, 0);
468 		if (error != 0)
469 			return;
470 
471 		cup.uaddr = child_clear_tid;
472 		cup.op = LINUX_FUTEX_WAKE;
473 		cup.val = 1;		/* wake one */
474 		cup.timeout = NULL;
475 		cup.uaddr2 = NULL;
476 		cup.val3 = 0;
477 		error = linux_sys_futex(td, &cup);
478 		/*
479 		 * this cannot happen at the moment and if this happens it
480 		 * probably means there is a user space bug
481 		 */
482 		if (error != 0)
483 			linux_msg(td, "futex stuff in thread_detach failed.");
484 	}
485 }
486