1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
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 #include <sys/param.h>
33 #include <sys/ktr.h>
34 #include <sys/lock.h>
35 #include <sys/mutex.h>
36 #include <sys/proc.h>
37 #include <sys/ptrace.h>
38 #include <sys/racct.h>
39 #include <sys/sched.h>
40 #include <sys/syscallsubr.h>
41 #include <sys/sx.h>
42 #include <sys/umtxvar.h>
43 #include <sys/unistd.h>
44
45 #include <vm/vm.h>
46 #include <vm/pmap.h>
47 #include <vm/vm_map.h>
48
49 #ifdef COMPAT_LINUX32
50 #include <machine/../linux32/linux.h>
51 #include <machine/../linux32/linux32_proto.h>
52 #else
53 #include <machine/../linux/linux.h>
54 #include <machine/../linux/linux_proto.h>
55 #endif
56 #include <compat/linux/linux.h>
57 #include <compat/linux/linux_emul.h>
58 #include <compat/linux/linux_fork.h>
59 #include <compat/linux/linux_futex.h>
60 #include <compat/linux/linux_mib.h>
61 #include <compat/linux/linux_misc.h>
62 #include <compat/linux/linux_util.h>
63
64 #ifdef LINUX_LEGACY_SYSCALLS
65 int
linux_fork(struct thread * td,struct linux_fork_args * args)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 bzero(&fr, sizeof(fr));
74 fr.fr_flags = RFFDG | RFPROC | RFSTOPPED;
75 fr.fr_procp = &p2;
76 if ((error = fork1(td, &fr)) != 0)
77 return (error);
78
79 td2 = FIRST_THREAD_IN_PROC(p2);
80
81 linux_proc_init(td, td2, false);
82
83 td->td_retval[0] = p2->p_pid;
84
85 /*
86 * Make this runnable after we are finished with it.
87 */
88 thread_lock(td2);
89 TD_SET_CAN_RUN(td2);
90 sched_add(td2, SRQ_BORING);
91
92 return (0);
93 }
94
95 int
linux_vfork(struct thread * td,struct linux_vfork_args * args)96 linux_vfork(struct thread *td, struct linux_vfork_args *args)
97 {
98 struct fork_req fr;
99 int error;
100 struct proc *p2;
101 struct thread *td2;
102
103 bzero(&fr, sizeof(fr));
104 fr.fr_flags = RFFDG | RFPROC | RFMEM | RFPPWAIT | RFSTOPPED;
105 fr.fr_procp = &p2;
106 if ((error = fork1(td, &fr)) != 0)
107 return (error);
108
109 td2 = FIRST_THREAD_IN_PROC(p2);
110
111 linux_proc_init(td, td2, false);
112
113 td->td_retval[0] = p2->p_pid;
114
115 /*
116 * Make this runnable after we are finished with it.
117 */
118 thread_lock(td2);
119 TD_SET_CAN_RUN(td2);
120 sched_add(td2, SRQ_BORING);
121
122 return (0);
123 }
124 #endif
125
126 static int
linux_clone_proc(struct thread * td,struct l_clone_args * args)127 linux_clone_proc(struct thread *td, struct l_clone_args *args)
128 {
129 struct fork_req fr;
130 int error, ff, f2;
131 struct proc *p2;
132 struct thread *td2;
133 int exit_signal;
134 struct linux_emuldata *em;
135
136 f2 = 0;
137 ff = RFPROC | RFSTOPPED;
138 if (LINUX_SIG_VALID(args->exit_signal)) {
139 exit_signal = linux_to_bsd_signal(args->exit_signal);
140 } else if (args->exit_signal != 0)
141 return (EINVAL);
142 else
143 exit_signal = 0;
144
145 if (args->flags & LINUX_CLONE_VM)
146 ff |= RFMEM;
147 if (args->flags & LINUX_CLONE_SIGHAND)
148 ff |= RFSIGSHARE;
149 if ((args->flags & LINUX_CLONE_CLEAR_SIGHAND) != 0)
150 f2 |= FR2_DROPSIG_CAUGHT;
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_tid == 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, false);
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_tid;
185 else
186 em->child_set_tid = NULL;
187
188 if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
189 em->child_clear_tid = args->child_tid;
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_tid,
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(td2, args->stack);
209
210 if (args->flags & LINUX_CLONE_SETTLS)
211 linux_set_cloned_tls(td2, PTRIN(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
linux_clone_thread(struct thread * td,struct l_clone_args * args)238 linux_clone_thread(struct thread *td, struct l_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_tid, args->child_tid);
248
249 if ((args->flags & LINUX_CLONE_PARENT) != 0)
250 return (EINVAL);
251 if (args->flags & LINUX_CLONE_PARENT_SETTID)
252 if (args->parent_tid == NULL)
253 return (EINVAL);
254
255 /* Threads should be created with own stack */
256 if (PTRIN(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 bzero(&newtd->td_startzero,
277 __rangeof(struct thread, td_startzero, td_endzero));
278 bcopy(&td->td_startcopy, &newtd->td_startcopy,
279 __rangeof(struct thread, td_startcopy, td_endcopy));
280
281 newtd->td_proc = p;
282 thread_cow_get(newtd, td);
283
284 cpu_copy_thread(newtd, td);
285
286 /* create the emuldata */
287 linux_proc_init(td, newtd, true);
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, PTRIN(args->tls));
294
295 if (args->flags & LINUX_CLONE_CHILD_SETTID)
296 em->child_set_tid = args->child_tid;
297 else
298 em->child_set_tid = NULL;
299
300 if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
301 em->child_clear_tid = args->child_tid;
302 else
303 em->child_clear_tid = NULL;
304
305 cpu_thread_clean(newtd);
306
307 linux_set_upcall(newtd, 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_tid,
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
linux_clone(struct thread * td,struct linux_clone_args * args)360 linux_clone(struct thread *td, struct linux_clone_args *args)
361 {
362 struct l_clone_args ca = {
363 .flags = (lower_32_bits(args->flags) & ~LINUX_CSIGNAL),
364 .child_tid = args->child_tidptr,
365 .parent_tid = args->parent_tidptr,
366 .exit_signal = (lower_32_bits(args->flags) & LINUX_CSIGNAL),
367 .stack = args->stack,
368 .tls = args->tls,
369 };
370
371 if (args->flags & LINUX_CLONE_THREAD)
372 return (linux_clone_thread(td, &ca));
373 else
374 return (linux_clone_proc(td, &ca));
375 }
376
377
378 static int
linux_clone3_args_valid(struct l_user_clone_args * uca)379 linux_clone3_args_valid(struct l_user_clone_args *uca)
380 {
381
382 /* Verify that no unknown flags are passed along. */
383 if ((uca->flags & ~(LINUX_CLONE_LEGACY_FLAGS |
384 LINUX_CLONE_CLEAR_SIGHAND | LINUX_CLONE_INTO_CGROUP)) != 0)
385 return (EINVAL);
386 if ((uca->flags & (LINUX_CLONE_DETACHED | LINUX_CSIGNAL)) != 0)
387 return (EINVAL);
388
389 if ((uca->flags & (LINUX_CLONE_SIGHAND | LINUX_CLONE_CLEAR_SIGHAND)) ==
390 (LINUX_CLONE_SIGHAND | LINUX_CLONE_CLEAR_SIGHAND))
391 return (EINVAL);
392 if ((uca->flags & (LINUX_CLONE_THREAD | LINUX_CLONE_PARENT)) != 0 &&
393 uca->exit_signal != 0)
394 return (EINVAL);
395
396 /* We don't support set_tid, only validate input. */
397 if (uca->set_tid_size > LINUX_MAX_PID_NS_LEVEL)
398 return (EINVAL);
399 if (uca->set_tid == 0 && uca->set_tid_size > 0)
400 return (EINVAL);
401 if (uca->set_tid != 0 && uca->set_tid_size == 0)
402 return (EINVAL);
403
404 if (uca->stack == 0 && uca->stack_size > 0)
405 return (EINVAL);
406 if (uca->stack != 0 && uca->stack_size == 0)
407 return (EINVAL);
408
409 /* Verify that higher 32bits of exit_signal are unset. */
410 if ((uca->exit_signal & ~(uint64_t)LINUX_CSIGNAL) != 0)
411 return (EINVAL);
412
413 /* Verify that no unsupported flags are passed along. */
414 if ((uca->flags & LINUX_CLONE_NEWTIME) != 0) {
415 LINUX_RATELIMIT_MSG("unsupported clone3 option CLONE_NEWTIME");
416 return (ENOSYS);
417 }
418 if ((uca->flags & LINUX_CLONE_INTO_CGROUP) != 0) {
419 LINUX_RATELIMIT_MSG("unsupported clone3 option CLONE_INTO_CGROUP");
420 return (ENOSYS);
421 }
422 if (uca->set_tid != 0 || uca->set_tid_size != 0) {
423 LINUX_RATELIMIT_MSG("unsupported clone3 set_tid");
424 return (ENOSYS);
425 }
426
427 return (0);
428 }
429
430 int
linux_clone3(struct thread * td,struct linux_clone3_args * args)431 linux_clone3(struct thread *td, struct linux_clone3_args *args)
432 {
433 struct l_user_clone_args *uca;
434 struct l_clone_args *ca;
435 size_t size;
436 int error;
437
438 if (args->usize > PAGE_SIZE)
439 return (E2BIG);
440 if (args->usize < LINUX_CLONE_ARGS_SIZE_VER0)
441 return (EINVAL);
442
443 /*
444 * usize can be less than size of struct clone_args, to avoid using
445 * of uninitialized data of struct clone_args, allocate at least
446 * sizeof(struct clone_args) storage and zero it.
447 */
448 size = max(args->usize, sizeof(*uca));
449 uca = malloc(size, M_LINUX, M_WAITOK | M_ZERO);
450 error = copyin(args->uargs, uca, args->usize);
451 if (error != 0)
452 goto out;
453 error = linux_clone3_args_valid(uca);
454 if (error != 0)
455 goto out;
456 ca = malloc(sizeof(*ca), M_LINUX, M_WAITOK | M_ZERO);
457 ca->flags = uca->flags;
458 ca->child_tid = PTRIN(uca->child_tid);
459 ca->parent_tid = PTRIN(uca->parent_tid);
460 ca->exit_signal = uca->exit_signal;
461 ca->stack = uca->stack + uca->stack_size;
462 ca->stack_size = uca->stack_size;
463 ca->tls = uca->tls;
464
465 if ((ca->flags & LINUX_CLONE_THREAD) != 0)
466 error = linux_clone_thread(td, ca);
467 else
468 error = linux_clone_proc(td, ca);
469 free(ca, M_LINUX);
470 out:
471 free(uca, M_LINUX);
472 return (error);
473 }
474
475 int
linux_exit(struct thread * td,struct linux_exit_args * args)476 linux_exit(struct thread *td, struct linux_exit_args *args)
477 {
478 struct linux_emuldata *em __diagused;
479
480 em = em_find(td);
481 KASSERT(em != NULL, ("exit: emuldata not found.\n"));
482
483 LINUX_CTR2(exit, "thread(%d) (%d)", em->em_tid, args->rval);
484
485 linux_thread_detach(td);
486
487 /*
488 * XXX. When the last two threads of a process
489 * exit via pthread_exit() try thr_exit() first.
490 */
491 kern_thr_exit(td);
492 exit1(td, args->rval, 0);
493 /* NOTREACHED */
494 }
495
496 int
linux_set_tid_address(struct thread * td,struct linux_set_tid_address_args * args)497 linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args)
498 {
499 struct linux_emuldata *em;
500
501 em = em_find(td);
502 KASSERT(em != NULL, ("set_tid_address: emuldata not found.\n"));
503
504 em->child_clear_tid = args->tidptr;
505
506 td->td_retval[0] = em->em_tid;
507
508 LINUX_CTR3(set_tid_address, "tidptr(%d) %p, returns %d",
509 em->em_tid, args->tidptr, td->td_retval[0]);
510
511 return (0);
512 }
513
514 void
linux_thread_detach(struct thread * td)515 linux_thread_detach(struct thread *td)
516 {
517 struct linux_emuldata *em;
518 int *child_clear_tid;
519 int error;
520
521 em = em_find(td);
522 KASSERT(em != NULL, ("thread_detach: emuldata not found.\n"));
523
524 LINUX_CTR1(thread_detach, "thread(%d)", em->em_tid);
525
526 release_futexes(td, em);
527
528 child_clear_tid = em->child_clear_tid;
529
530 if (child_clear_tid != NULL) {
531 LINUX_CTR2(thread_detach, "thread(%d) %p",
532 em->em_tid, child_clear_tid);
533
534 error = suword32(child_clear_tid, 0);
535 if (error != 0)
536 return;
537
538 error = futex_wake(td, child_clear_tid, 1, false);
539 /*
540 * this cannot happen at the moment and if this happens it
541 * probably means there is a user space bug
542 */
543 if (error != 0)
544 linux_msg(td, "futex stuff in thread_detach failed.");
545 }
546
547 /*
548 * Do not rely on the robust list which is maintained by userspace,
549 * cleanup remaining pi (if any) after release_futexes anyway.
550 */
551 umtx_thread_exit(td);
552 }
553