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: src/sys/compat/linux/linux_emul.c,v 1.22 2008/10/31 10:38:30 kib Exp $");
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/kernel.h>
38 #include <sys/lock.h>
39 #include <sys/malloc.h>
40 #include <sys/mutex.h>
41 #include <sys/sx.h>
42 #include <sys/proc.h>
43 #include <sys/syscallsubr.h>
44 #include <sys/sysproto.h>
45 #include <sys/unistd.h>
46
47 #ifdef COMPAT_LINUX32
48 #include <machine/../linux32/linux.h>
49 #include <machine/../linux32/linux32_proto.h>
50 #else
51 #include <machine/../linux/linux.h>
52 #include <machine/../linux/linux_proto.h>
53 #endif
54
55 #include <compat/linux/linux_emul.h>
56 #include <compat/linux/linux_futex.h>
57
58 struct sx emul_shared_lock;
59 struct mtx emul_lock;
60
61 /* this returns locked reference to the emuldata entry (if found) */
62 struct linux_emuldata *
63 em_find(struct proc *p, int locked)
64 {
65 struct linux_emuldata *em;
66
67 if (locked == EMUL_DOLOCK)
68 EMUL_LOCK(&emul_lock);
69
70 em = p->p_emuldata;
71
72 if (em == NULL && locked == EMUL_DOLOCK)
73 EMUL_UNLOCK(&emul_lock);
74
75 return (em);
76 }
77
78 int
79 linux_proc_init(struct thread *td, pid_t child, int flags)
80 {
81 struct linux_emuldata *em, *p_em;
82 struct proc *p;
83
84 if (child != 0) {
85 /* non-exec call */
86 em = malloc(sizeof *em, M_LINUX, M_WAITOK | M_ZERO);
87 em->pid = child;
88 em->pdeath_signal = 0;
89 em->robust_futexes = NULL;
90 if (flags & LINUX_CLONE_THREAD) {
91 /* handled later in the code */
92 } else {
93 struct linux_emuldata_shared *s;
94
95 s = malloc(sizeof *s, M_LINUX, M_WAITOK | M_ZERO);
96 s->refs = 1;
97 s->group_pid = child;
98
99 LIST_INIT(&s->threads);
100 em->shared = s;
101 }
102 } else {
103 /* lookup the old one */
104 em = em_find(td->td_proc, EMUL_DOLOCK);
105 KASSERT(em != NULL, ("proc_init: emuldata not found in exec case.\n"));
106 }
107
108 em->child_clear_tid = NULL;
109 em->child_set_tid = NULL;
110
111 /*
112 * allocate the shared struct only in clone()/fork cases in the case
113 * of clone() td = calling proc and child = pid of the newly created
114 * proc
115 */
116 if (child != 0) {
117 if (flags & LINUX_CLONE_THREAD) {
118 /* lookup the parent */
119 /*
120 * we dont have to lock the p_em because
121 * its waiting for us in linux_clone so
122 * there is no chance of it changing the
123 * p_em->shared address
124 */
125 p_em = em_find(td->td_proc, EMUL_DONTLOCK);
126 KASSERT(p_em != NULL, ("proc_init: parent emuldata not found for CLONE_THREAD\n"));
127 em->shared = p_em->shared;
128 EMUL_SHARED_WLOCK(&emul_shared_lock);
129 em->shared->refs++;
130 EMUL_SHARED_WUNLOCK(&emul_shared_lock);
131 } else {
132 /*
133 * handled earlier to avoid malloc(M_WAITOK) with
134 * rwlock held
135 */
136 }
137 }
138 if (child != 0) {
139 EMUL_SHARED_WLOCK(&emul_shared_lock);
140 LIST_INSERT_HEAD(&em->shared->threads, em, threads);
141 EMUL_SHARED_WUNLOCK(&emul_shared_lock);
142
143 p = pfind(child);
144 KASSERT(p != NULL, ("process not found in proc_init\n"));
145 p->p_emuldata = em;
146 PROC_UNLOCK(p);
147 } else
148 EMUL_UNLOCK(&emul_lock);
149
150 return (0);
151 }
152
153 void
154 linux_proc_exit(void *arg __unused, struct proc *p)
155 {
156 struct linux_emuldata *em;
157 int error;
158 struct thread *td = FIRST_THREAD_IN_PROC(p);
159 int *child_clear_tid;
160 struct proc *q, *nq;
161
162 if (__predict_true(p->p_sysent != &elf_linux_sysvec))
163 return;
164
165 release_futexes(p);
166
167 /* find the emuldata */
168 em = em_find(p, EMUL_DOLOCK);
169
170 KASSERT(em != NULL, ("proc_exit: emuldata not found.\n"));
171
172 /* reparent all procs that are not a thread leader to initproc */
173 if (em->shared->group_pid != p->p_pid) {
174 child_clear_tid = em->child_clear_tid;
175 EMUL_UNLOCK(&emul_lock);
176 sx_xlock(&proctree_lock);
177 wakeup(initproc);
178 PROC_LOCK(p);
179 proc_reparent(p, initproc);
180 p->p_sigparent = SIGCHLD;
181 PROC_UNLOCK(p);
182 sx_xunlock(&proctree_lock);
183 } else {
184 child_clear_tid = em->child_clear_tid;
185 EMUL_UNLOCK(&emul_lock);
186 }
187
188 EMUL_SHARED_WLOCK(&emul_shared_lock);
189 LIST_REMOVE(em, threads);
190
191 em->shared->refs--;
192 if (em->shared->refs == 0) {
193 EMUL_SHARED_WUNLOCK(&emul_shared_lock);
194 free(em->shared, M_LINUX);
195 } else
196 EMUL_SHARED_WUNLOCK(&emul_shared_lock);
197
198 if (child_clear_tid != NULL) {
199 struct linux_sys_futex_args cup;
200 int null = 0;
201
202 error = copyout(&null, child_clear_tid, sizeof(null));
203 if (error) {
204 free(em, M_LINUX);
205 return;
206 }
207
208 /* futexes stuff */
209 cup.uaddr = child_clear_tid;
210 cup.op = LINUX_FUTEX_WAKE;
211 cup.val = 0x7fffffff; /* Awake everyone */
212 cup.timeout = NULL;
213 cup.uaddr2 = NULL;
214 cup.val3 = 0;
215 error = linux_sys_futex(FIRST_THREAD_IN_PROC(p), &cup);
216 /*
217 * this cannot happen at the moment and if this happens it
218 * probably means there is a user space bug
219 */
220 if (error)
221 printf(LMSG("futex stuff in proc_exit failed.\n"));
222 }
223
224 /* clean the stuff up */
225 free(em, M_LINUX);
226
227 /* this is a little weird but rewritten from exit1() */
228 sx_xlock(&proctree_lock);
229 q = LIST_FIRST(&p->p_children);
230 for (; q != NULL; q = nq) {
231 nq = LIST_NEXT(q, p_sibling);
232 if (q->p_flag & P_WEXIT)
233 continue;
234 if (__predict_false(q->p_sysent != &elf_linux_sysvec))
235 continue;
236 em = em_find(q, EMUL_DOLOCK);
237 KASSERT(em != NULL, ("linux_reparent: emuldata not found: %i\n", q->p_pid));
238 PROC_LOCK(q);
239 if ((q->p_flag & P_WEXIT) == 0 && em->pdeath_signal != 0) {
240 psignal(q, em->pdeath_signal);
241 }
242 PROC_UNLOCK(q);
243 EMUL_UNLOCK(&emul_lock);
244 }
245 sx_xunlock(&proctree_lock);
246 }
247
248 /*
249 * This is used in a case of transition from FreeBSD binary execing to linux binary
250 * in this case we create linux emuldata proc entry with the pid of the currently running
251 * process.
252 */
253 void
254 linux_proc_exec(void *arg __unused, struct proc *p, struct image_params *imgp)
255 {
256 if (__predict_false(imgp->sysent == &elf_linux_sysvec
257 && p->p_sysent != &elf_linux_sysvec))
258 linux_proc_init(FIRST_THREAD_IN_PROC(p), p->p_pid, 0);
259 if (__predict_false(imgp->sysent != &elf_linux_sysvec
260 && p->p_sysent == &elf_linux_sysvec)) {
261 struct linux_emuldata *em;
262
263 /*
264 * XXX:There's a race because here we assign p->p_emuldata NULL
265 * but the process is still counted as linux one for a short
266 * time so some other process might reference it and try to
267 * access its p->p_emuldata and panicing on a NULL reference.
268 */
269 em = em_find(p, EMUL_DONTLOCK);
270
271 KASSERT(em != NULL, ("proc_exec: emuldata not found.\n"));
272
273 EMUL_SHARED_WLOCK(&emul_shared_lock);
274 LIST_REMOVE(em, threads);
275
276 PROC_LOCK(p);
277 p->p_emuldata = NULL;
278 PROC_UNLOCK(p);
279
280 em->shared->refs--;
281 if (em->shared->refs == 0) {
282 EMUL_SHARED_WUNLOCK(&emul_shared_lock);
283 free(em->shared, M_LINUX);
284 } else
285 EMUL_SHARED_WUNLOCK(&emul_shared_lock);
286
287 free(em, M_LINUX);
288 }
289 }
290
291 void
292 linux_schedtail(void *arg __unused, struct proc *p)
293 {
294 struct linux_emuldata *em;
295 int error = 0;
296 int *child_set_tid;
297
298 if (__predict_true(p->p_sysent != &elf_linux_sysvec))
299 return;
300
301 /* find the emuldata */
302 em = em_find(p, EMUL_DOLOCK);
303
304 KASSERT(em != NULL, ("linux_schedtail: emuldata not found.\n"));
305 child_set_tid = em->child_set_tid;
306 EMUL_UNLOCK(&emul_lock);
307
308 if (child_set_tid != NULL)
309 error = copyout(&p->p_pid, (int *)child_set_tid,
310 sizeof(p->p_pid));
311
312 return;
313 }
314
315 int
316 linux_set_tid_address(struct thread *td, struct linux_set_tid_address_args *args)
317 {
318 struct linux_emuldata *em;
319
320 #ifdef DEBUG
321 if (ldebug(set_tid_address))
322 printf(ARGS(set_tid_address, "%p"), args->tidptr);
323 #endif
324
325 /* find the emuldata */
326 em = em_find(td->td_proc, EMUL_DOLOCK);
327
328 KASSERT(em != NULL, ("set_tid_address: emuldata not found.\n"));
329
330 em->child_clear_tid = args->tidptr;
331 td->td_retval[0] = td->td_proc->p_pid;
332
333 EMUL_UNLOCK(&emul_lock);
334 return 0;
335 }
336 Cache object: fe3f2cd0fb3f02c84d2a0eb85645a450
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