xref: /freebsd/sys/compat/linux/linux_fork.c (revision 0a36787e4c1fa0cf77dcf83be0867178476e372b)
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/unistd.h>
49 #include <sys/wait.h>
50 
51 #include <vm/vm.h>
52 #include <vm/pmap.h>
53 #include <vm/vm_map.h>
54 
55 #ifdef COMPAT_LINUX32
56 #include <machine/../linux32/linux.h>
57 #include <machine/../linux32/linux32_proto.h>
58 #else
59 #include <machine/../linux/linux.h>
60 #include <machine/../linux/linux_proto.h>
61 #endif
62 #include <compat/linux/linux_emul.h>
63 #include <compat/linux/linux_futex.h>
64 #include <compat/linux/linux_misc.h>
65 #include <compat/linux/linux_util.h>
66 
67 #ifdef LINUX_LEGACY_SYSCALLS
68 int
69 linux_fork(struct thread *td, struct linux_fork_args *args)
70 {
71 	struct fork_req fr;
72 	int error;
73 	struct proc *p2;
74 	struct thread *td2;
75 
76 	bzero(&fr, sizeof(fr));
77 	fr.fr_flags = RFFDG | RFPROC | RFSTOPPED;
78 	fr.fr_procp = &p2;
79 	if ((error = fork1(td, &fr)) != 0)
80 		return (error);
81 
82 	td2 = FIRST_THREAD_IN_PROC(p2);
83 
84 	linux_proc_init(td, td2, 0);
85 
86 	td->td_retval[0] = p2->p_pid;
87 
88 	/*
89 	 * Make this runnable after we are finished with it.
90 	 */
91 	thread_lock(td2);
92 	TD_SET_CAN_RUN(td2);
93 	sched_add(td2, SRQ_BORING);
94 
95 	return (0);
96 }
97 
98 int
99 linux_vfork(struct thread *td, struct linux_vfork_args *args)
100 {
101 	struct fork_req fr;
102 	int error;
103 	struct proc *p2;
104 	struct thread *td2;
105 
106 	bzero(&fr, sizeof(fr));
107 	fr.fr_flags = RFFDG | RFPROC | RFMEM | RFPPWAIT | RFSTOPPED;
108 	fr.fr_procp = &p2;
109 	if ((error = fork1(td, &fr)) != 0)
110 		return (error);
111 
112 	td2 = FIRST_THREAD_IN_PROC(p2);
113 
114 	linux_proc_init(td, td2, 0);
115 
116 	td->td_retval[0] = p2->p_pid;
117 
118 	/*
119 	 * Make this runnable after we are finished with it.
120 	 */
121 	thread_lock(td2);
122 	TD_SET_CAN_RUN(td2);
123 	sched_add(td2, SRQ_BORING);
124 
125 	return (0);
126 }
127 #endif
128 
129 static int
130 linux_clone_proc(struct thread *td, struct linux_clone_args *args)
131 {
132 	struct fork_req fr;
133 	int error, ff = RFPROC | RFSTOPPED, f2;
134 	struct proc *p2;
135 	struct thread *td2;
136 	int exit_signal;
137 	struct linux_emuldata *em;
138 
139 	f2 = 0;
140 	exit_signal = args->flags & 0x000000ff;
141 	if (LINUX_SIG_VALID(exit_signal)) {
142 		exit_signal = linux_to_bsd_signal(exit_signal);
143 	} else if (exit_signal != 0)
144 		return (EINVAL);
145 
146 	if (args->flags & LINUX_CLONE_VM)
147 		ff |= RFMEM;
148 	if (args->flags & LINUX_CLONE_SIGHAND)
149 		ff |= RFSIGSHARE;
150 	if (args->flags & LINUX_CLONE_FILES) {
151 		if (!(args->flags & LINUX_CLONE_FS))
152 			f2 |= FR2_SHARE_PATHS;
153 	} else {
154 		ff |= RFFDG;
155 		if (args->flags & LINUX_CLONE_FS)
156 			f2 |= FR2_SHARE_PATHS;
157 	}
158 
159 	if (args->flags & LINUX_CLONE_PARENT_SETTID)
160 		if (args->parent_tidptr == NULL)
161 			return (EINVAL);
162 
163 	if (args->flags & LINUX_CLONE_VFORK)
164 		ff |= RFPPWAIT;
165 
166 	bzero(&fr, sizeof(fr));
167 	fr.fr_flags = ff;
168 	fr.fr_flags2 = f2;
169 	fr.fr_procp = &p2;
170 	error = fork1(td, &fr);
171 	if (error)
172 		return (error);
173 
174 	td2 = FIRST_THREAD_IN_PROC(p2);
175 
176 	/* create the emuldata */
177 	linux_proc_init(td, td2, args->flags);
178 
179 	em = em_find(td2);
180 	KASSERT(em != NULL, ("clone_proc: emuldata not found.\n"));
181 
182 	if (args->flags & LINUX_CLONE_CHILD_SETTID)
183 		em->child_set_tid = args->child_tidptr;
184 	else
185 		em->child_set_tid = NULL;
186 
187 	if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
188 		em->child_clear_tid = args->child_tidptr;
189 	else
190 		em->child_clear_tid = NULL;
191 
192 	if (args->flags & LINUX_CLONE_PARENT_SETTID) {
193 		error = copyout(&p2->p_pid, args->parent_tidptr,
194 		    sizeof(p2->p_pid));
195 		if (error)
196 			linux_msg(td, "copyout p_pid failed!");
197 	}
198 
199 	PROC_LOCK(p2);
200 	p2->p_sigparent = exit_signal;
201 	PROC_UNLOCK(p2);
202 	/*
203 	 * In a case of stack = NULL, we are supposed to COW calling process
204 	 * stack. This is what normal fork() does, so we just keep tf_rsp arg
205 	 * intact.
206 	 */
207 	linux_set_upcall(td2, PTROUT(args->stack));
208 
209 	if (args->flags & LINUX_CLONE_SETTLS)
210 		linux_set_cloned_tls(td2, args->tls);
211 
212 	/*
213 	 * If CLONE_PARENT is set, then the parent of the new process will be
214 	 * the same as that of the calling process.
215 	 */
216 	if (args->flags & LINUX_CLONE_PARENT) {
217 		sx_xlock(&proctree_lock);
218 		PROC_LOCK(p2);
219 		proc_reparent(p2, td->td_proc->p_pptr, true);
220 		PROC_UNLOCK(p2);
221 		sx_xunlock(&proctree_lock);
222 	}
223 
224 	/*
225 	 * Make this runnable after we are finished with it.
226 	 */
227 	thread_lock(td2);
228 	TD_SET_CAN_RUN(td2);
229 	sched_add(td2, SRQ_BORING);
230 
231 	td->td_retval[0] = p2->p_pid;
232 
233 	return (0);
234 }
235 
236 static int
237 linux_clone_thread(struct thread *td, struct linux_clone_args *args)
238 {
239 	struct linux_emuldata *em;
240 	struct thread *newtd;
241 	struct proc *p;
242 	int error;
243 
244 	LINUX_CTR4(clone_thread, "thread(%d) flags %x ptid %p ctid %p",
245 	    td->td_tid, (unsigned)args->flags,
246 	    args->parent_tidptr, args->child_tidptr);
247 
248 	if ((args->flags & LINUX_CLONE_PARENT) != 0)
249 		return (EINVAL);
250 	if (args->flags & LINUX_CLONE_PARENT_SETTID)
251 		if (args->parent_tidptr == NULL)
252 			return (EINVAL);
253 
254 	/* Threads should be created with own stack */
255 	if (args->stack == NULL)
256 		return (EINVAL);
257 
258 	p = td->td_proc;
259 
260 #ifdef RACCT
261 	if (racct_enable) {
262 		PROC_LOCK(p);
263 		error = racct_add(p, RACCT_NTHR, 1);
264 		PROC_UNLOCK(p);
265 		if (error != 0)
266 			return (EPROCLIM);
267 	}
268 #endif
269 
270 	/* Initialize our td */
271 	error = kern_thr_alloc(p, 0, &newtd);
272 	if (error)
273 		goto fail;
274 
275 	cpu_copy_thread(newtd, td);
276 
277 	bzero(&newtd->td_startzero,
278 	    __rangeof(struct thread, td_startzero, td_endzero));
279 	bcopy(&td->td_startcopy, &newtd->td_startcopy,
280 	    __rangeof(struct thread, td_startcopy, td_endcopy));
281 
282 	newtd->td_proc = p;
283 	thread_cow_get(newtd, td);
284 
285 	/* create the emuldata */
286 	linux_proc_init(td, newtd, args->flags);
287 
288 	em = em_find(newtd);
289 	KASSERT(em != NULL, ("clone_thread: emuldata not found.\n"));
290 
291 	if (args->flags & LINUX_CLONE_SETTLS)
292 		linux_set_cloned_tls(newtd, args->tls);
293 
294 	if (args->flags & LINUX_CLONE_CHILD_SETTID)
295 		em->child_set_tid = args->child_tidptr;
296 	else
297 		em->child_set_tid = NULL;
298 
299 	if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
300 		em->child_clear_tid = args->child_tidptr;
301 	else
302 		em->child_clear_tid = NULL;
303 
304 	cpu_thread_clean(newtd);
305 
306 	linux_set_upcall(newtd, PTROUT(args->stack));
307 
308 	PROC_LOCK(p);
309 	p->p_flag |= P_HADTHREADS;
310 	thread_link(newtd, p);
311 	bcopy(p->p_comm, newtd->td_name, sizeof(newtd->td_name));
312 
313 	thread_lock(td);
314 	/* let the scheduler know about these things. */
315 	sched_fork_thread(td, newtd);
316 	thread_unlock(td);
317 	if (P_SHOULDSTOP(p))
318 		newtd->td_flags |= TDF_ASTPENDING | TDF_NEEDSUSPCHK;
319 
320 	if (p->p_ptevents & PTRACE_LWP)
321 		newtd->td_dbgflags |= TDB_BORN;
322 	PROC_UNLOCK(p);
323 
324 	tidhash_add(newtd);
325 
326 	LINUX_CTR2(clone_thread, "thread(%d) successful clone to %d",
327 	    td->td_tid, newtd->td_tid);
328 
329 	if (args->flags & LINUX_CLONE_PARENT_SETTID) {
330 		error = copyout(&newtd->td_tid, args->parent_tidptr,
331 		    sizeof(newtd->td_tid));
332 		if (error)
333 			linux_msg(td, "clone_thread: copyout td_tid failed!");
334 	}
335 
336 	/*
337 	 * Make this runnable after we are finished with it.
338 	 */
339 	thread_lock(newtd);
340 	TD_SET_CAN_RUN(newtd);
341 	sched_add(newtd, SRQ_BORING);
342 
343 	td->td_retval[0] = newtd->td_tid;
344 
345 	return (0);
346 
347 fail:
348 #ifdef RACCT
349 	if (racct_enable) {
350 		PROC_LOCK(p);
351 		racct_sub(p, RACCT_NTHR, 1);
352 		PROC_UNLOCK(p);
353 	}
354 #endif
355 	return (error);
356 }
357 
358 int
359 linux_clone(struct thread *td, struct linux_clone_args *args)
360 {
361 
362 	if (args->flags & LINUX_CLONE_THREAD)
363 		return (linux_clone_thread(td, args));
364 	else
365 		return (linux_clone_proc(td, args));
366 }
367 
368 int
369 linux_exit(struct thread *td, struct linux_exit_args *args)
370 {
371 	struct linux_emuldata *em;
372 
373 	em = em_find(td);
374 	KASSERT(em != NULL, ("exit: emuldata not found.\n"));
375 
376 	LINUX_CTR2(exit, "thread(%d) (%d)", em->em_tid, args->rval);
377 
378 	linux_thread_detach(td);
379 
380 	/*
381 	 * XXX. When the last two threads of a process
382 	 * exit via pthread_exit() try thr_exit() first.
383 	 */
384 	kern_thr_exit(td);
385 	exit1(td, args->rval, 0);
386 		/* NOTREACHED */
387 }
388 
389 int
390 linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args)
391 {
392 	struct linux_emuldata *em;
393 
394 	em = em_find(td);
395 	KASSERT(em != NULL, ("set_tid_address: emuldata not found.\n"));
396 
397 	em->child_clear_tid = args->tidptr;
398 
399 	td->td_retval[0] = em->em_tid;
400 
401 	LINUX_CTR3(set_tid_address, "tidptr(%d) %p, returns %d",
402 	    em->em_tid, args->tidptr, td->td_retval[0]);
403 
404 	return (0);
405 }
406 
407 void
408 linux_thread_detach(struct thread *td)
409 {
410 	struct linux_sys_futex_args cup;
411 	struct linux_emuldata *em;
412 	int *child_clear_tid;
413 	int error;
414 
415 	em = em_find(td);
416 	KASSERT(em != NULL, ("thread_detach: emuldata not found.\n"));
417 
418 	LINUX_CTR1(thread_detach, "thread(%d)", em->em_tid);
419 
420 	release_futexes(td, em);
421 
422 	child_clear_tid = em->child_clear_tid;
423 
424 	if (child_clear_tid != NULL) {
425 		LINUX_CTR2(thread_detach, "thread(%d) %p",
426 		    em->em_tid, child_clear_tid);
427 
428 		error = suword32(child_clear_tid, 0);
429 		if (error != 0)
430 			return;
431 
432 		cup.uaddr = child_clear_tid;
433 		cup.op = LINUX_FUTEX_WAKE;
434 		cup.val = 1;		/* wake one */
435 		cup.timeout = NULL;
436 		cup.uaddr2 = NULL;
437 		cup.val3 = 0;
438 		error = linux_sys_futex(td, &cup);
439 		/*
440 		 * this cannot happen at the moment and if this happens it
441 		 * probably means there is a user space bug
442 		 */
443 		if (error != 0)
444 			linux_msg(td, "futex stuff in thread_detach failed.");
445 	}
446 }
447