1 /*-
2 * Copyright (c) 2004 Tim J. Robbins
3 * Copyright (c) 2002 Doug Rabson
4 * Copyright (c) 2000 Marcel Moolenaar
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer
12 * in this position and unchanged.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
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_fork.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/lock.h>
39 #include <sys/mutex.h>
40 #include <sys/proc.h>
41 #include <sys/sched.h>
42 #include <sys/sdt.h>
43 #include <sys/sx.h>
44 #include <sys/unistd.h>
45
46 #ifdef COMPAT_LINUX32
47 #include <machine/../linux32/linux.h>
48 #include <machine/../linux32/linux32_proto.h>
49 #else
50 #include <machine/../linux/linux.h>
51 #include <machine/../linux/linux_proto.h>
52 #endif
53 #include <compat/linux/linux_dtrace.h>
54 #include <compat/linux/linux_signal.h>
55 #include <compat/linux/linux_emul.h>
56
57 /* DTrace init */
58 LIN_SDT_PROVIDER_DECLARE(LINUX_DTRACE);
59
60 /* Linuxulator-global DTrace probes */
61 LIN_SDT_PROBE_DECLARE(locks, emul_lock, locked);
62 LIN_SDT_PROBE_DECLARE(locks, emul_lock, unlock);
63
64
65 int
66 linux_fork(struct thread *td, struct linux_fork_args *args)
67 {
68 int error;
69 struct proc *p2;
70 struct thread *td2;
71
72 #ifdef DEBUG
73 if (ldebug(fork))
74 printf(ARGS(fork, ""));
75 #endif
76
77 if ((error = fork1(td, RFFDG | RFPROC | RFSTOPPED, 0, &p2, NULL, 0))
78 != 0)
79 return (error);
80
81 td->td_retval[0] = p2->p_pid;
82 td->td_retval[1] = 0;
83
84 error = linux_proc_init(td, td->td_retval[0], 0);
85 if (error)
86 return (error);
87
88 td2 = FIRST_THREAD_IN_PROC(p2);
89
90 /*
91 * Make this runnable after we are finished with it.
92 */
93 thread_lock(td2);
94 TD_SET_CAN_RUN(td2);
95 sched_add(td2, SRQ_BORING);
96 thread_unlock(td2);
97
98 return (0);
99 }
100
101 int
102 linux_vfork(struct thread *td, struct linux_vfork_args *args)
103 {
104 int error;
105 struct proc *p2;
106 struct thread *td2;
107
108 #ifdef DEBUG
109 if (ldebug(vfork))
110 printf(ARGS(vfork, ""));
111 #endif
112
113 /* Exclude RFPPWAIT */
114 if ((error = fork1(td, RFFDG | RFPROC | RFMEM | RFSTOPPED, 0, &p2,
115 NULL, 0)) != 0)
116 return (error);
117
118 td->td_retval[0] = p2->p_pid;
119
120 error = linux_proc_init(td, td->td_retval[0], 0);
121 if (error)
122 return (error);
123
124 PROC_LOCK(p2);
125 p2->p_flag |= P_PPWAIT;
126 PROC_UNLOCK(p2);
127
128 td2 = FIRST_THREAD_IN_PROC(p2);
129
130 /*
131 * Make this runnable after we are finished with it.
132 */
133 thread_lock(td2);
134 TD_SET_CAN_RUN(td2);
135 sched_add(td2, SRQ_BORING);
136 thread_unlock(td2);
137
138 /* wait for the children to exit, ie. emulate vfork */
139 PROC_LOCK(p2);
140 while (p2->p_flag & P_PPWAIT)
141 cv_wait(&p2->p_pwait, &p2->p_mtx);
142 PROC_UNLOCK(p2);
143
144 return (0);
145 }
146
147 int
148 linux_clone(struct thread *td, struct linux_clone_args *args)
149 {
150 int error, ff = RFPROC | RFSTOPPED;
151 struct proc *p2;
152 struct thread *td2;
153 int exit_signal;
154 struct linux_emuldata *em;
155
156 #ifdef DEBUG
157 if (ldebug(clone)) {
158 printf(ARGS(clone, "flags %x, stack %p, parent tid: %p, "
159 "child tid: %p"), (unsigned)args->flags,
160 args->stack, args->parent_tidptr, args->child_tidptr);
161 }
162 #endif
163
164 exit_signal = args->flags & 0x000000ff;
165 if (LINUX_SIG_VALID(exit_signal)) {
166 if (exit_signal <= LINUX_SIGTBLSZ)
167 exit_signal =
168 linux_to_bsd_signal[_SIG_IDX(exit_signal)];
169 } else if (exit_signal != 0)
170 return (EINVAL);
171
172 if (args->flags & LINUX_CLONE_VM)
173 ff |= RFMEM;
174 if (args->flags & LINUX_CLONE_SIGHAND)
175 ff |= RFSIGSHARE;
176 /*
177 * XXX: In Linux, sharing of fs info (chroot/cwd/umask)
178 * and open files is independant. In FreeBSD, its in one
179 * structure but in reality it does not cause any problems
180 * because both of these flags are usually set together.
181 */
182 if (!(args->flags & (LINUX_CLONE_FILES | LINUX_CLONE_FS)))
183 ff |= RFFDG;
184
185 /*
186 * Attempt to detect when linux_clone(2) is used for creating
187 * kernel threads. Unfortunately despite the existence of the
188 * CLONE_THREAD flag, version of linuxthreads package used in
189 * most popular distros as of beginning of 2005 doesn't make
190 * any use of it. Therefore, this detection relies on
191 * empirical observation that linuxthreads sets certain
192 * combination of flags, so that we can make more or less
193 * precise detection and notify the FreeBSD kernel that several
194 * processes are in fact part of the same threading group, so
195 * that special treatment is necessary for signal delivery
196 * between those processes and fd locking.
197 */
198 if ((args->flags & 0xffffff00) == LINUX_THREADING_FLAGS)
199 ff |= RFTHREAD;
200
201 if (args->flags & LINUX_CLONE_PARENT_SETTID)
202 if (args->parent_tidptr == NULL)
203 return (EINVAL);
204
205 error = fork1(td, ff, 0, &p2, NULL, 0);
206 if (error)
207 return (error);
208
209 if (args->flags & (LINUX_CLONE_PARENT | LINUX_CLONE_THREAD)) {
210 sx_xlock(&proctree_lock);
211 PROC_LOCK(p2);
212 proc_reparent(p2, td->td_proc->p_pptr);
213 PROC_UNLOCK(p2);
214 sx_xunlock(&proctree_lock);
215 }
216
217 /* create the emuldata */
218 error = linux_proc_init(td, p2->p_pid, args->flags);
219 /* reference it - no need to check this */
220 em = em_find(p2, EMUL_DOLOCK);
221 KASSERT(em != NULL, ("clone: emuldata not found."));
222 /* and adjust it */
223
224 if (args->flags & LINUX_CLONE_THREAD) {
225 #ifdef notyet
226 PROC_LOCK(p2);
227 p2->p_pgrp = td->td_proc->p_pgrp;
228 PROC_UNLOCK(p2);
229 #endif
230 exit_signal = 0;
231 }
232
233 if (args->flags & LINUX_CLONE_CHILD_SETTID)
234 em->child_set_tid = args->child_tidptr;
235 else
236 em->child_set_tid = NULL;
237
238 if (args->flags & LINUX_CLONE_CHILD_CLEARTID)
239 em->child_clear_tid = args->child_tidptr;
240 else
241 em->child_clear_tid = NULL;
242
243 EMUL_UNLOCK(&emul_lock);
244
245 if (args->flags & LINUX_CLONE_PARENT_SETTID) {
246 error = copyout(&p2->p_pid, args->parent_tidptr,
247 sizeof(p2->p_pid));
248 if (error)
249 printf(LMSG("copyout failed!"));
250 }
251
252 PROC_LOCK(p2);
253 p2->p_sigparent = exit_signal;
254 PROC_UNLOCK(p2);
255 td2 = FIRST_THREAD_IN_PROC(p2);
256 /*
257 * In a case of stack = NULL, we are supposed to COW calling process
258 * stack. This is what normal fork() does, so we just keep tf_rsp arg
259 * intact.
260 */
261 if (args->stack)
262 linux_set_upcall_kse(td2, PTROUT(args->stack));
263
264 if (args->flags & LINUX_CLONE_SETTLS)
265 linux_set_cloned_tls(td2, args->tls);
266
267 #ifdef DEBUG
268 if (ldebug(clone))
269 printf(LMSG("clone: successful rfork to %d, "
270 "stack %p sig = %d"), (int)p2->p_pid, args->stack,
271 exit_signal);
272 #endif
273 if (args->flags & LINUX_CLONE_VFORK) {
274 PROC_LOCK(p2);
275 p2->p_flag |= P_PPWAIT;
276 PROC_UNLOCK(p2);
277 }
278
279 /*
280 * Make this runnable after we are finished with it.
281 */
282 thread_lock(td2);
283 TD_SET_CAN_RUN(td2);
284 sched_add(td2, SRQ_BORING);
285 thread_unlock(td2);
286
287 td->td_retval[0] = p2->p_pid;
288 td->td_retval[1] = 0;
289
290 if (args->flags & LINUX_CLONE_VFORK) {
291 /* wait for the children to exit, ie. emulate vfork */
292 PROC_LOCK(p2);
293 while (p2->p_flag & P_PPWAIT)
294 cv_wait(&p2->p_pwait, &p2->p_mtx);
295 PROC_UNLOCK(p2);
296 }
297
298 return (0);
299 }
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