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