xref: /freebsd/sys/compat/linux/linux_fork.c (revision c66ec88fed842fbaad62c30d510644ceb7bd2d71)
1 /*-
2  * SPDX-License-Identifier: BSD-2-Clause-FreeBSD
3  *
4  * Copyright (c) 2004 Tim J. Robbins
5  * Copyright (c) 2002 Doug Rabson
6  * Copyright (c) 2000 Marcel Moolenaar
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  * 1. Redistributions of source code must retain the above copyright
13  *    notice, this list of conditions and the following disclaimer
14  *    in this position and unchanged.
15  * 2. Redistributions in binary form must reproduce the above copyright
16  *    notice, this list of conditions and the following disclaimer in the
17  *    documentation and/or other materials provided with the distribution.
18  *
19  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
20  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
21  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
22  * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
23  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
24  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
28  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
29  */
30 
31 #include <sys/cdefs.h>
32 __FBSDID("$FreeBSD$");
33 
34 #include "opt_compat.h"
35 
36 #include <sys/param.h>
37 #include <sys/systm.h>
38 #include <sys/imgact.h>
39 #include <sys/ktr.h>
40 #include <sys/lock.h>
41 #include <sys/mutex.h>
42 #include <sys/proc.h>
43 #include <sys/ptrace.h>
44 #include <sys/racct.h>
45 #include <sys/sched.h>
46 #include <sys/syscallsubr.h>
47 #include <sys/sx.h>
48 #include <sys/umtx.h>
49 #include <sys/unistd.h>
50 #include <sys/wait.h>
51 
52 #include <vm/vm.h>
53 #include <vm/pmap.h>
54 #include <vm/vm_map.h>
55 
56 #ifdef COMPAT_LINUX32
57 #include <machine/../linux32/linux.h>
58 #include <machine/../linux32/linux32_proto.h>
59 #else
60 #include <machine/../linux/linux.h>
61 #include <machine/../linux/linux_proto.h>
62 #endif
63 #include <compat/linux/linux_emul.h>
64 #include <compat/linux/linux_futex.h>
65 #include <compat/linux/linux_misc.h>
66 #include <compat/linux/linux_util.h>
67 
68 #ifdef LINUX_LEGACY_SYSCALLS
69 int
70 linux_fork(struct thread *td, struct linux_fork_args *args)
71 {
72 	struct fork_req fr;
73 	int error;
74 	struct proc *p2;
75 	struct thread *td2;
76 
77 	bzero(&fr, sizeof(fr));
78 	fr.fr_flags = RFFDG | RFPROC | RFSTOPPED;
79 	fr.fr_procp = &p2;
80 	if ((error = fork1(td, &fr)) != 0)
81 		return (error);
82 
83 	td2 = FIRST_THREAD_IN_PROC(p2);
84 
85 	linux_proc_init(td, td2, 0);
86 
87 	td->td_retval[0] = p2->p_pid;
88 
89 	/*
90 	 * Make this runnable after we are finished with it.
91 	 */
92 	thread_lock(td2);
93 	TD_SET_CAN_RUN(td2);
94 	sched_add(td2, SRQ_BORING);
95 
96 	return (0);
97 }
98 
99 int
100 linux_vfork(struct thread *td, struct linux_vfork_args *args)
101 {
102 	struct fork_req fr;
103 	int error;
104 	struct proc *p2;
105 	struct thread *td2;
106 
107 	bzero(&fr, sizeof(fr));
108 	fr.fr_flags = RFFDG | RFPROC | RFMEM | RFPPWAIT | RFSTOPPED;
109 	fr.fr_procp = &p2;
110 	if ((error = fork1(td, &fr)) != 0)
111 		return (error);
112 
113 	td2 = FIRST_THREAD_IN_PROC(p2);
114 
115 	linux_proc_init(td, td2, 0);
116 
117 	td->td_retval[0] = p2->p_pid;
118 
119 	/*
120 	 * Make this runnable after we are finished with it.
121 	 */
122 	thread_lock(td2);
123 	TD_SET_CAN_RUN(td2);
124 	sched_add(td2, SRQ_BORING);
125 
126 	return (0);
127 }
128 #endif
129 
130 static int
131 linux_clone_proc(struct thread *td, struct linux_clone_args *args)
132 {
133 	struct fork_req fr;
134 	int error, ff = RFPROC | RFSTOPPED, f2;
135 	struct proc *p2;
136 	struct thread *td2;
137 	int exit_signal;
138 	struct linux_emuldata *em;
139 
140 	f2 = 0;
141 	exit_signal = args->flags & 0x000000ff;
142 	if (LINUX_SIG_VALID(exit_signal)) {
143 		exit_signal = linux_to_bsd_signal(exit_signal);
144 	} else if (exit_signal != 0)
145 		return (EINVAL);
146 
147 	if (args->flags & LINUX_CLONE_VM)
148 		ff |= RFMEM;
149 	if (args->flags & LINUX_CLONE_SIGHAND)
150 		ff |= RFSIGSHARE;
151 	if (args->flags & LINUX_CLONE_FILES) {
152 		if (!(args->flags & LINUX_CLONE_FS))
153 			f2 |= FR2_SHARE_PATHS;
154 	} else {
155 		ff |= RFFDG;
156 		if (args->flags & LINUX_CLONE_FS)
157 			f2 |= FR2_SHARE_PATHS;
158 	}
159 
160 	if (args->flags & LINUX_CLONE_PARENT_SETTID)
161 		if (args->parent_tidptr == NULL)
162 			return (EINVAL);
163 
164 	if (args->flags & LINUX_CLONE_VFORK)
165 		ff |= RFPPWAIT;
166 
167 	bzero(&fr, sizeof(fr));
168 	fr.fr_flags = ff;
169 	fr.fr_flags2 = f2;
170 	fr.fr_procp = &p2;
171 	error = fork1(td, &fr);
172 	if (error)
173 		return (error);
174 
175 	td2 = FIRST_THREAD_IN_PROC(p2);
176 
177 	/* create the emuldata */
178 	linux_proc_init(td, td2, args->flags);
179 
180 	em = em_find(td2);
181 	KASSERT(em != NULL, ("clone_proc: emuldata not found.\n"));
182 
183 	if (args->flags & LINUX_CLONE_CHILD_SETTID)
184 		em->child_set_tid = args->child_tidptr;
185 	else
186 		em->child_set_tid = NULL;
187 
188 	if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
189 		em->child_clear_tid = args->child_tidptr;
190 	else
191 		em->child_clear_tid = NULL;
192 
193 	if (args->flags & LINUX_CLONE_PARENT_SETTID) {
194 		error = copyout(&p2->p_pid, args->parent_tidptr,
195 		    sizeof(p2->p_pid));
196 		if (error)
197 			linux_msg(td, "copyout p_pid failed!");
198 	}
199 
200 	PROC_LOCK(p2);
201 	p2->p_sigparent = exit_signal;
202 	PROC_UNLOCK(p2);
203 	/*
204 	 * In a case of stack = NULL, we are supposed to COW calling process
205 	 * stack. This is what normal fork() does, so we just keep tf_rsp arg
206 	 * intact.
207 	 */
208 	linux_set_upcall_kse(td2, PTROUT(args->stack));
209 
210 	if (args->flags & LINUX_CLONE_SETTLS)
211 		linux_set_cloned_tls(td2, args->tls);
212 
213 	/*
214 	 * If CLONE_PARENT is set, then the parent of the new process will be
215 	 * the same as that of the calling process.
216 	 */
217 	if (args->flags & LINUX_CLONE_PARENT) {
218 		sx_xlock(&proctree_lock);
219 		PROC_LOCK(p2);
220 		proc_reparent(p2, td->td_proc->p_pptr, true);
221 		PROC_UNLOCK(p2);
222 		sx_xunlock(&proctree_lock);
223 	}
224 
225 	/*
226 	 * Make this runnable after we are finished with it.
227 	 */
228 	thread_lock(td2);
229 	TD_SET_CAN_RUN(td2);
230 	sched_add(td2, SRQ_BORING);
231 
232 	td->td_retval[0] = p2->p_pid;
233 
234 	return (0);
235 }
236 
237 static int
238 linux_clone_thread(struct thread *td, struct linux_clone_args *args)
239 {
240 	struct linux_emuldata *em;
241 	struct thread *newtd;
242 	struct proc *p;
243 	int error;
244 
245 	LINUX_CTR4(clone_thread, "thread(%d) flags %x ptid %p ctid %p",
246 	    td->td_tid, (unsigned)args->flags,
247 	    args->parent_tidptr, args->child_tidptr);
248 
249 	if ((args->flags & LINUX_CLONE_PARENT) != 0)
250 		return (EINVAL);
251 	if (args->flags & LINUX_CLONE_PARENT_SETTID)
252 		if (args->parent_tidptr == NULL)
253 			return (EINVAL);
254 
255 	/* Threads should be created with own stack */
256 	if (args->stack == NULL)
257 		return (EINVAL);
258 
259 	p = td->td_proc;
260 
261 #ifdef RACCT
262 	if (racct_enable) {
263 		PROC_LOCK(p);
264 		error = racct_add(p, RACCT_NTHR, 1);
265 		PROC_UNLOCK(p);
266 		if (error != 0)
267 			return (EPROCLIM);
268 	}
269 #endif
270 
271 	/* Initialize our td */
272 	error = kern_thr_alloc(p, 0, &newtd);
273 	if (error)
274 		goto fail;
275 
276 	cpu_copy_thread(newtd, td);
277 
278 	bzero(&newtd->td_startzero,
279 	    __rangeof(struct thread, td_startzero, td_endzero));
280 	bcopy(&td->td_startcopy, &newtd->td_startcopy,
281 	    __rangeof(struct thread, td_startcopy, td_endcopy));
282 
283 	newtd->td_proc = p;
284 	thread_cow_get(newtd, td);
285 
286 	/* create the emuldata */
287 	linux_proc_init(td, newtd, args->flags);
288 
289 	em = em_find(newtd);
290 	KASSERT(em != NULL, ("clone_thread: emuldata not found.\n"));
291 
292 	if (args->flags & LINUX_CLONE_SETTLS)
293 		linux_set_cloned_tls(newtd, args->tls);
294 
295 	if (args->flags & LINUX_CLONE_CHILD_SETTID)
296 		em->child_set_tid = args->child_tidptr;
297 	else
298 		em->child_set_tid = NULL;
299 
300 	if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
301 		em->child_clear_tid = args->child_tidptr;
302 	else
303 		em->child_clear_tid = NULL;
304 
305 	cpu_thread_clean(newtd);
306 
307 	linux_set_upcall_kse(newtd, PTROUT(args->stack));
308 
309 	PROC_LOCK(p);
310 	p->p_flag |= P_HADTHREADS;
311 	thread_link(newtd, p);
312 	bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
313 
314 	thread_lock(td);
315 	/* let the scheduler know about these things. */
316 	sched_fork_thread(td, newtd);
317 	thread_unlock(td);
318 	if (P_SHOULDSTOP(p))
319 		newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
320 
321 	if (p->p_ptevents & PTRACE_LWP)
322 		newtd->td_dbgflags |= TDB_BORN;
323 	PROC_UNLOCK(p);
324 
325 	tidhash_add(newtd);
326 
327 	LINUX_CTR2(clone_thread, "thread(%d) successful clone to %d",
328 	    td->td_tid, newtd->td_tid);
329 
330 	if (args->flags & LINUX_CLONE_PARENT_SETTID) {
331 		error = copyout(&newtd->td_tid, args->parent_tidptr,
332 		    sizeof(newtd->td_tid));
333 		if (error)
334 			linux_msg(td, "clone_thread: copyout td_tid failed!");
335 	}
336 
337 	/*
338 	 * Make this runnable after we are finished with it.
339 	 */
340 	thread_lock(newtd);
341 	TD_SET_CAN_RUN(newtd);
342 	sched_add(newtd, SRQ_BORING);
343 
344 	td->td_retval[0] = newtd->td_tid;
345 
346 	return (0);
347 
348 fail:
349 #ifdef RACCT
350 	if (racct_enable) {
351 		PROC_LOCK(p);
352 		racct_sub(p, RACCT_NTHR, 1);
353 		PROC_UNLOCK(p);
354 	}
355 #endif
356 	return (error);
357 }
358 
359 int
360 linux_clone(struct thread *td, struct linux_clone_args *args)
361 {
362 
363 	if (args->flags & LINUX_CLONE_THREAD)
364 		return (linux_clone_thread(td, args));
365 	else
366 		return (linux_clone_proc(td, args));
367 }
368 
369 int
370 linux_exit(struct thread *td, struct linux_exit_args *args)
371 {
372 	struct linux_emuldata *em;
373 
374 	em = em_find(td);
375 	KASSERT(em != NULL, ("exit: emuldata not found.\n"));
376 
377 	LINUX_CTR2(exit, "thread(%d) (%d)", em->em_tid, args->rval);
378 
379 	umtx_thread_exit(td);
380 
381 	linux_thread_detach(td);
382 
383 	/*
384 	 * XXX. When the last two threads of a process
385 	 * exit via pthread_exit() try thr_exit() first.
386 	 */
387 	kern_thr_exit(td);
388 	exit1(td, args->rval, 0);
389 		/* NOTREACHED */
390 }
391 
392 int
393 linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args)
394 {
395 	struct linux_emuldata *em;
396 
397 	em = em_find(td);
398 	KASSERT(em != NULL, ("set_tid_address: emuldata not found.\n"));
399 
400 	em->child_clear_tid = args->tidptr;
401 
402 	td->td_retval[0] = em->em_tid;
403 
404 	LINUX_CTR3(set_tid_address, "tidptr(%d) %p, returns %d",
405 	    em->em_tid, args->tidptr, td->td_retval[0]);
406 
407 	return (0);
408 }
409 
410 void
411 linux_thread_detach(struct thread *td)
412 {
413 	struct linux_sys_futex_args cup;
414 	struct linux_emuldata *em;
415 	int *child_clear_tid;
416 	int error;
417 
418 	em = em_find(td);
419 	KASSERT(em != NULL, ("thread_detach: emuldata not found.\n"));
420 
421 	LINUX_CTR1(thread_detach, "thread(%d)", em->em_tid);
422 
423 	release_futexes(td, em);
424 
425 	child_clear_tid = em->child_clear_tid;
426 
427 	if (child_clear_tid != NULL) {
428 		LINUX_CTR2(thread_detach, "thread(%d) %p",
429 		    em->em_tid, child_clear_tid);
430 
431 		error = suword32(child_clear_tid, 0);
432 		if (error != 0)
433 			return;
434 
435 		cup.uaddr = child_clear_tid;
436 		cup.op = LINUX_FUTEX_WAKE;
437 		cup.val = 1;		/* wake one */
438 		cup.timeout = NULL;
439 		cup.uaddr2 = NULL;
440 		cup.val3 = 0;
441 		error = linux_sys_futex(td, &cup);
442 		/*
443 		 * this cannot happen at the moment and if this happens it
444 		 * probably means there is a user space bug
445 		 */
446 		if (error != 0)
447 			linux_msg(td, "futex stuff in thread_detach failed.");
448 	}
449 }
450