1 /*-
2 * Copyright (c) 2006 Roman Divacky
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
7 * are met:
8 * 1. Redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer
10 * in this position and unchanged.
11 * 2. Redistributions in binary form must reproduce the above copyright
12 * notice, this list of conditions and the following disclaimer in the
13 * documentation and/or other materials provided with the distribution.
14 * 3. The name of the author may not be used to endorse or promote products
15 * derived from this software without specific prior written permission
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: releng/9.2/sys/compat/linux/linux_emul.c 246290 2013-02-03 18:14:37Z dchagin $");
31
32 #include "opt_compat.h"
33 #include "opt_kdtrace.h"
34
35 #include <sys/param.h>
36 #include <sys/systm.h>
37 #include <sys/imgact.h>
38 #include <sys/kernel.h>
39 #include <sys/lock.h>
40 #include <sys/malloc.h>
41 #include <sys/mutex.h>
42 #include <sys/sdt.h>
43 #include <sys/sx.h>
44 #include <sys/proc.h>
45 #include <sys/syscallsubr.h>
46 #include <sys/sysent.h>
47 #include <sys/sysproto.h>
48 #include <sys/unistd.h>
49
50 #ifdef COMPAT_LINUX32
51 #include <machine/../linux32/linux.h>
52 #include <machine/../linux32/linux32_proto.h>
53 #else
54 #include <machine/../linux/linux.h>
55 #include <machine/../linux/linux_proto.h>
56 #endif
57
58 #include <compat/linux/linux_dtrace.h>
59 #include <compat/linux/linux_emul.h>
60 #include <compat/linux/linux_futex.h>
61
62 /**
63 * Special DTrace provider for the linuxulator.
64 *
65 * In this file we define the provider for the entire linuxulator. All
66 * modules (= files of the linuxulator) use it.
67 *
68 * We define a different name depending on the emulated bitsize, see
69 * ../../<ARCH>/linux{,32}/linux.h, e.g.:
70 * native bitsize = linuxulator
71 * amd64, 32bit emulation = linuxulator32
72 */
73 LIN_SDT_PROVIDER_DEFINE(LINUX_DTRACE);
74
75 /**
76 * Special DTrace module "locks", it covers some linuxulator internal
77 * locks.
78 */
79 LIN_SDT_PROBE_DEFINE1(locks, emul_lock, locked, "struct mtx *");
80 LIN_SDT_PROBE_DEFINE1(locks, emul_lock, unlock, "struct mtx *");
81 LIN_SDT_PROBE_DEFINE1(locks, emul_shared_rlock, locked, "struct sx *");
82 LIN_SDT_PROBE_DEFINE1(locks, emul_shared_rlock, unlock, "struct sx *");
83 LIN_SDT_PROBE_DEFINE1(locks, emul_shared_wlock, locked, "struct sx *");
84 LIN_SDT_PROBE_DEFINE1(locks, emul_shared_wlock, unlock, "struct sx *");
85
86 /**
87 * DTrace probes in this module.
88 */
89 LIN_SDT_PROBE_DEFINE2(emul, em_find, entry, "struct proc *", "int");
90 LIN_SDT_PROBE_DEFINE0(emul, em_find, return);
91 LIN_SDT_PROBE_DEFINE3(emul, proc_init, entry, "struct thread *", "pid_t",
92 "int");
93 LIN_SDT_PROBE_DEFINE0(emul, proc_init, create_thread);
94 LIN_SDT_PROBE_DEFINE0(emul, proc_init, fork);
95 LIN_SDT_PROBE_DEFINE0(emul, proc_init, exec);
96 LIN_SDT_PROBE_DEFINE0(emul, proc_init, return);
97 LIN_SDT_PROBE_DEFINE1(emul, proc_exit, entry, "struct proc *");
98 LIN_SDT_PROBE_DEFINE0(emul, proc_exit, futex_failed);
99 LIN_SDT_PROBE_DEFINE3(emul, proc_exit, reparent, "pid_t", "pid_t",
100 "struct proc *");
101 LIN_SDT_PROBE_DEFINE1(emul, proc_exit, child_clear_tid_error, "int");
102 LIN_SDT_PROBE_DEFINE0(emul, proc_exit, return);
103 LIN_SDT_PROBE_DEFINE2(emul, proc_exec, entry, "struct proc *",
104 "struct image_params *");
105 LIN_SDT_PROBE_DEFINE0(emul, proc_exec, return);
106 LIN_SDT_PROBE_DEFINE0(emul, linux_schedtail, entry);
107 LIN_SDT_PROBE_DEFINE1(emul, linux_schedtail, copyout_error, "int");
108 LIN_SDT_PROBE_DEFINE0(emul, linux_schedtail, return);
109 LIN_SDT_PROBE_DEFINE1(emul, linux_set_tid_address, entry, "int *");
110 LIN_SDT_PROBE_DEFINE0(emul, linux_set_tid_address, return);
111 LIN_SDT_PROBE_DEFINE2(emul, linux_kill_threads, entry, "struct thread *",
112 "int");
113 LIN_SDT_PROBE_DEFINE1(emul, linux_kill_threads, kill, "pid_t");
114 LIN_SDT_PROBE_DEFINE0(emul, linux_kill_threads, return);
115
116 struct sx emul_shared_lock;
117 struct mtx emul_lock;
118
119 /* this returns locked reference to the emuldata entry (if found) */
120 struct linux_emuldata *
121 em_find(struct proc *p, int locked)
122 {
123 struct linux_emuldata *em;
124
125 LIN_SDT_PROBE2(emul, em_find, entry, p, locked);
126
127 if (locked == EMUL_DOLOCK)
128 EMUL_LOCK(&emul_lock);
129
130 em = p->p_emuldata;
131
132 if (em == NULL && locked == EMUL_DOLOCK)
133 EMUL_UNLOCK(&emul_lock);
134
135 LIN_SDT_PROBE1(emul, em_find, return, em);
136 return (em);
137 }
138
139 int
140 linux_proc_init(struct thread *td, pid_t child, int flags)
141 {
142 struct linux_emuldata *em, *p_em;
143 struct proc *p;
144
145 LIN_SDT_PROBE3(emul, proc_init, entry, td, child, flags);
146
147 if (child != 0) {
148 /* fork or create a thread */
149 em = malloc(sizeof *em, M_LINUX, M_WAITOK | M_ZERO);
150 em->pid = child;
151 em->pdeath_signal = 0;
152 em->flags = 0;
153 em->robust_futexes = NULL;
154 if (flags & LINUX_CLONE_THREAD) {
155 /* handled later in the code */
156 LIN_SDT_PROBE0(emul, proc_init, create_thread);
157 } else {
158 struct linux_emuldata_shared *s;
159
160 LIN_SDT_PROBE0(emul, proc_init, fork);
161
162 s = malloc(sizeof *s, M_LINUX, M_WAITOK | M_ZERO);
163 s->refs = 1;
164 s->group_pid = child;
165
166 LIST_INIT(&s->threads);
167 em->shared = s;
168 }
169 } else {
170 /* exec */
171 LIN_SDT_PROBE0(emul, proc_init, exec);
172
173 /* lookup the old one */
174 em = em_find(td->td_proc, EMUL_DOLOCK);
175 KASSERT(em != NULL, ("proc_init: emuldata not found in exec case.\n"));
176 }
177
178 em->child_clear_tid = NULL;
179 em->child_set_tid = NULL;
180
181 /*
182 * allocate the shared struct only in clone()/fork cases in the case
183 * of clone() td = calling proc and child = pid of the newly created
184 * proc
185 */
186 if (child != 0) {
187 if (flags & LINUX_CLONE_THREAD) {
188 /* lookup the parent */
189 /*
190 * we dont have to lock the p_em because
191 * its waiting for us in linux_clone so
192 * there is no chance of it changing the
193 * p_em->shared address
194 */
195 p_em = em_find(td->td_proc, EMUL_DONTLOCK);
196 KASSERT(p_em != NULL, ("proc_init: parent emuldata not found for CLONE_THREAD\n"));
197 em->shared = p_em->shared;
198 EMUL_SHARED_WLOCK(&emul_shared_lock);
199 em->shared->refs++;
200 EMUL_SHARED_WUNLOCK(&emul_shared_lock);
201 } else {
202 /*
203 * handled earlier to avoid malloc(M_WAITOK) with
204 * rwlock held
205 */
206 }
207
208 EMUL_SHARED_WLOCK(&emul_shared_lock);
209 LIST_INSERT_HEAD(&em->shared->threads, em, threads);
210 EMUL_SHARED_WUNLOCK(&emul_shared_lock);
211
212 p = pfind(child);
213 KASSERT(p != NULL, ("process not found in proc_init\n"));
214 p->p_emuldata = em;
215 PROC_UNLOCK(p);
216 } else
217 EMUL_UNLOCK(&emul_lock);
218
219 LIN_SDT_PROBE0(emul, proc_init, return);
220 return (0);
221 }
222
223 void
224 linux_proc_exit(void *arg __unused, struct proc *p)
225 {
226 struct linux_emuldata *em;
227 int error, shared_flags, shared_xstat;
228 struct thread *td = FIRST_THREAD_IN_PROC(p);
229 int *child_clear_tid;
230 struct proc *q, *nq;
231
232 if (__predict_true(p->p_sysent != &elf_linux_sysvec))
233 return;
234
235 LIN_SDT_PROBE1(emul, proc_exit, entry, p);
236
237 release_futexes(p);
238
239 /* find the emuldata */
240 em = em_find(p, EMUL_DOLOCK);
241
242 KASSERT(em != NULL, ("proc_exit: emuldata not found.\n"));
243
244 /* reparent all procs that are not a thread leader to initproc */
245 if (em->shared->group_pid != p->p_pid) {
246 LIN_SDT_PROBE3(emul, proc_exit, reparent,
247 em->shared->group_pid, p->p_pid, p);
248
249 child_clear_tid = em->child_clear_tid;
250 EMUL_UNLOCK(&emul_lock);
251 sx_xlock(&proctree_lock);
252 wakeup(initproc);
253 PROC_LOCK(p);
254 proc_reparent(p, initproc);
255 p->p_sigparent = SIGCHLD;
256 PROC_UNLOCK(p);
257 sx_xunlock(&proctree_lock);
258 } else {
259 child_clear_tid = em->child_clear_tid;
260 EMUL_UNLOCK(&emul_lock);
261 }
262
263 EMUL_SHARED_WLOCK(&emul_shared_lock);
264 shared_flags = em->shared->flags;
265 shared_xstat = em->shared->xstat;
266 LIST_REMOVE(em, threads);
267
268 em->shared->refs--;
269 if (em->shared->refs == 0) {
270 EMUL_SHARED_WUNLOCK(&emul_shared_lock);
271 free(em->shared, M_LINUX);
272 } else
273 EMUL_SHARED_WUNLOCK(&emul_shared_lock);
274
275 if ((shared_flags & EMUL_SHARED_HASXSTAT) != 0)
276 p->p_xstat = shared_xstat;
277
278 if (child_clear_tid != NULL) {
279 struct linux_sys_futex_args cup;
280 int null = 0;
281
282 error = copyout(&null, child_clear_tid, sizeof(null));
283 if (error) {
284 LIN_SDT_PROBE1(emul, proc_exit,
285 child_clear_tid_error, error);
286
287 free(em, M_LINUX);
288
289 LIN_SDT_PROBE0(emul, proc_exit, return);
290 return;
291 }
292
293 /* futexes stuff */
294 cup.uaddr = child_clear_tid;
295 cup.op = LINUX_FUTEX_WAKE;
296 cup.val = 0x7fffffff; /* Awake everyone */
297 cup.timeout = NULL;
298 cup.uaddr2 = NULL;
299 cup.val3 = 0;
300 error = linux_sys_futex(FIRST_THREAD_IN_PROC(p), &cup);
301 /*
302 * this cannot happen at the moment and if this happens it
303 * probably means there is a user space bug
304 */
305 if (error) {
306 LIN_SDT_PROBE0(emul, proc_exit, futex_failed);
307 printf(LMSG("futex stuff in proc_exit failed.\n"));
308 }
309 }
310
311 /* clean the stuff up */
312 free(em, M_LINUX);
313
314 /* this is a little weird but rewritten from exit1() */
315 sx_xlock(&proctree_lock);
316 q = LIST_FIRST(&p->p_children);
317 for (; q != NULL; q = nq) {
318 nq = LIST_NEXT(q, p_sibling);
319 if (q->p_flag & P_WEXIT)
320 continue;
321 if (__predict_false(q->p_sysent != &elf_linux_sysvec))
322 continue;
323 em = em_find(q, EMUL_DOLOCK);
324 KASSERT(em != NULL, ("linux_reparent: emuldata not found: %i\n", q->p_pid));
325 PROC_LOCK(q);
326 if ((q->p_flag & P_WEXIT) == 0 && em->pdeath_signal != 0) {
327 kern_psignal(q, em->pdeath_signal);
328 }
329 PROC_UNLOCK(q);
330 EMUL_UNLOCK(&emul_lock);
331 }
332 sx_xunlock(&proctree_lock);
333
334 LIN_SDT_PROBE0(emul, proc_exit, return);
335 }
336
337 /*
338 * This is used in a case of transition from FreeBSD binary execing to linux binary
339 * in this case we create linux emuldata proc entry with the pid of the currently running
340 * process.
341 */
342 void
343 linux_proc_exec(void *arg __unused, struct proc *p, struct image_params *imgp)
344 {
345 if (__predict_false(imgp->sysent == &elf_linux_sysvec)) {
346 LIN_SDT_PROBE2(emul, proc_exec, entry, p, imgp);
347 }
348 if (__predict_false(imgp->sysent == &elf_linux_sysvec
349 && p->p_sysent != &elf_linux_sysvec))
350 linux_proc_init(FIRST_THREAD_IN_PROC(p), p->p_pid, 0);
351 if (__predict_false((p->p_sysent->sv_flags & SV_ABI_MASK) ==
352 SV_ABI_LINUX))
353 /* Kill threads regardless of imgp->sysent value */
354 linux_kill_threads(FIRST_THREAD_IN_PROC(p), SIGKILL);
355 if (__predict_false(imgp->sysent != &elf_linux_sysvec
356 && p->p_sysent == &elf_linux_sysvec)) {
357 struct linux_emuldata *em;
358
359 /*
360 * XXX:There's a race because here we assign p->p_emuldata NULL
361 * but the process is still counted as linux one for a short
362 * time so some other process might reference it and try to
363 * access its p->p_emuldata and panicing on a NULL reference.
364 */
365 em = em_find(p, EMUL_DONTLOCK);
366
367 KASSERT(em != NULL, ("proc_exec: emuldata not found.\n"));
368
369 EMUL_SHARED_WLOCK(&emul_shared_lock);
370 LIST_REMOVE(em, threads);
371
372 PROC_LOCK(p);
373 p->p_emuldata = NULL;
374 PROC_UNLOCK(p);
375
376 em->shared->refs--;
377 if (em->shared->refs == 0) {
378 EMUL_SHARED_WUNLOCK(&emul_shared_lock);
379 free(em->shared, M_LINUX);
380 } else
381 EMUL_SHARED_WUNLOCK(&emul_shared_lock);
382
383 free(em, M_LINUX);
384 }
385
386 if (__predict_false(imgp->sysent == &elf_linux_sysvec)) {
387 LIN_SDT_PROBE0(emul, proc_exec, return);
388 }
389 }
390
391 void
392 linux_schedtail(struct thread *td)
393 {
394 struct linux_emuldata *em;
395 struct proc *p;
396 int error = 0;
397 int *child_set_tid;
398
399 p = td->td_proc;
400
401 LIN_SDT_PROBE1(emul, linux_schedtail, entry, p);
402
403 /* find the emuldata */
404 em = em_find(p, EMUL_DOLOCK);
405
406 KASSERT(em != NULL, ("linux_schedtail: emuldata not found.\n"));
407 child_set_tid = em->child_set_tid;
408 EMUL_UNLOCK(&emul_lock);
409
410 if (child_set_tid != NULL) {
411 error = copyout(&p->p_pid, (int *)child_set_tid,
412 sizeof(p->p_pid));
413
414 if (error != 0) {
415 LIN_SDT_PROBE1(emul, linux_schedtail, copyout_error,
416 error);
417 }
418 }
419
420 LIN_SDT_PROBE0(emul, linux_schedtail, return);
421
422 return;
423 }
424
425 int
426 linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args)
427 {
428 struct linux_emuldata *em;
429
430 LIN_SDT_PROBE1(emul, linux_set_tid_address, entry, args->tidptr);
431
432 /* find the emuldata */
433 em = em_find(td->td_proc, EMUL_DOLOCK);
434
435 KASSERT(em != NULL, ("set_tid_address: emuldata not found.\n"));
436
437 em->child_clear_tid = args->tidptr;
438 td->td_retval[0] = td->td_proc->p_pid;
439
440 EMUL_UNLOCK(&emul_lock);
441
442 LIN_SDT_PROBE0(emul, linux_set_tid_address, return);
443 return 0;
444 }
445
446 void
447 linux_kill_threads(struct thread *td, int sig)
448 {
449 struct linux_emuldata *em, *td_em, *tmp_em;
450 struct proc *sp;
451
452 LIN_SDT_PROBE2(emul, linux_kill_threads, entry, td, sig);
453
454 td_em = em_find(td->td_proc, EMUL_DONTLOCK);
455
456 KASSERT(td_em != NULL, ("linux_kill_threads: emuldata not found.\n"));
457
458 EMUL_SHARED_RLOCK(&emul_shared_lock);
459 LIST_FOREACH_SAFE(em, &td_em->shared->threads, threads, tmp_em) {
460 if (em->pid == td_em->pid)
461 continue;
462
463 sp = pfind(em->pid);
464 if ((sp->p_flag & P_WEXIT) == 0)
465 kern_psignal(sp, sig);
466 PROC_UNLOCK(sp);
467
468 LIN_SDT_PROBE1(emul, linux_kill_threads, kill, em->pid);
469 }
470 EMUL_SHARED_RUNLOCK(&emul_shared_lock);
471
472 LIN_SDT_PROBE0(emul, linux_kill_threads, return);
473 }
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