linux_emul.c revision 293546 
1/*-
2 * Copyright (c) 2006 Roman Divacky
3 * Copyright (c) 2013 Dmitry Chagin
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions
8 * are met:
9 * 1. Redistributions of source code must retain the above copyright
10 *    notice, this list of conditions and the following disclaimer
11 *    in this position and unchanged.
12 * 2. Redistributions in binary form must reproduce the above copyright
13 *    notice, this list of conditions and the following disclaimer in the
14 *    documentation and/or other materials provided with the distribution.
15 * 3. The name of the author may not be used to endorse or promote products
16 *    derived from this software without specific prior written permission
17 *
18 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
19 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
20 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
21 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
22 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
23 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
27 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 */
29
30#include <sys/cdefs.h>
31__FBSDID("$FreeBSD: stable/10/sys/compat/linux/linux_emul.c 293546 2016-01-09 16:44:17Z dchagin $");
32
33#include <sys/param.h>
34#include <sys/systm.h>
35#include <sys/imgact.h>
36#include <sys/kernel.h>
37#include <sys/ktr.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/sysent.h>
45
46#include <compat/linux/linux_emul.h>
47#include <compat/linux/linux_misc.h>
48#include <compat/linux/linux_util.h>
49
50
51/*
52 * This returns reference to the thread emuldata entry (if found)
53 *
54 * Hold PROC_LOCK when referencing emuldata from other threads.
55 */
56struct linux_emuldata *
57em_find(struct thread *td)
58{
59	struct linux_emuldata *em;
60
61	em = td->td_emuldata;
62
63	return (em);
64}
65
66/*
67 * This returns reference to the proc pemuldata entry (if found)
68 *
69 * Hold PROC_LOCK when referencing proc pemuldata from other threads.
70 * Hold LINUX_PEM_LOCK wher referencing pemuldata members.
71 */
72struct linux_pemuldata *
73pem_find(struct proc *p)
74{
75	struct linux_pemuldata *pem;
76
77	pem = p->p_emuldata;
78
79	return (pem);
80}
81
82void
83linux_proc_init(struct thread *td, struct thread *newtd, int flags)
84{
85	struct linux_emuldata *em;
86	struct linux_pemuldata *pem;
87	struct epoll_emuldata *emd;
88
89	if (newtd != NULL) {
90		/* non-exec call */
91		em = malloc(sizeof(*em), M_TEMP, M_WAITOK | M_ZERO);
92		em->pdeath_signal = 0;
93		em->robust_futexes = NULL;
94		if (flags & LINUX_CLONE_THREAD) {
95			LINUX_CTR1(proc_init, "thread newtd(%d)",
96			    newtd->td_tid);
97
98			em->em_tid = newtd->td_tid;
99		} else {
100			LINUX_CTR1(proc_init, "fork newtd(%d)",
101			    newtd->td_proc->p_pid);
102
103			em->em_tid = newtd->td_proc->p_pid;
104
105			pem = malloc(sizeof(*pem), M_LINUX, M_WAITOK | M_ZERO);
106			sx_init(&pem->pem_sx, "lpemlk");
107			newtd->td_proc->p_emuldata = pem;
108		}
109		newtd->td_emuldata = em;
110	} else {
111		/* exec */
112		LINUX_CTR1(proc_init, "exec newtd(%d)",
113		    td->td_proc->p_pid);
114
115		/* lookup the old one */
116		em = em_find(td);
117		KASSERT(em != NULL, ("proc_init: emuldata not found in exec case.\n"));
118
119		em->em_tid = td->td_proc->p_pid;
120
121		 /* epoll should be destroyed in a case of exec. */
122		pem = pem_find(td->td_proc);
123		KASSERT(pem != NULL, ("proc_exit: proc emuldata not found.\n"));
124
125		if (pem->epoll != NULL) {
126			emd = pem->epoll;
127			pem->epoll = NULL;
128			free(emd, M_EPOLL);
129		}
130	}
131
132	em->child_clear_tid = NULL;
133	em->child_set_tid = NULL;
134}
135
136void
137linux_proc_exit(void *arg __unused, struct proc *p)
138{
139	struct linux_pemuldata *pem;
140	struct epoll_emuldata *emd;
141	struct thread *td = curthread;
142
143	if (__predict_false(SV_CURPROC_ABI() != SV_ABI_LINUX))
144		return;
145
146	pem = pem_find(p);
147	if (pem == NULL)
148		return;
149	(p->p_sysent->sv_thread_detach)(td);
150
151	p->p_emuldata = NULL;
152
153	if (pem->epoll != NULL) {
154		emd = pem->epoll;
155		pem->epoll = NULL;
156		free(emd, M_EPOLL);
157	}
158
159	sx_destroy(&pem->pem_sx);
160	free(pem, M_LINUX);
161}
162
163int
164linux_common_execve(struct thread *td, struct image_args *eargs)
165{
166	struct linux_pemuldata *pem;
167	struct epoll_emuldata *emd;
168	struct linux_emuldata *em;
169	struct proc *p;
170	int error;
171
172	p = td->td_proc;
173
174	/*
175	 * Unlike FreeBSD abort all other threads before
176	 * proceeding exec.
177	 */
178	PROC_LOCK(p);
179	/* See exit1() comments. */
180	thread_suspend_check(0);
181	while (p->p_flag & P_HADTHREADS) {
182		if (!thread_single(p, SINGLE_EXIT))
183			break;
184		thread_suspend_check(0);
185	}
186	PROC_UNLOCK(p);
187
188	error = kern_execve(td, eargs, NULL);
189	if (error != 0)
190		return (error);
191
192	/*
193	 * In a case of transition from Linux binary execing to
194	 * FreeBSD binary we destroy linux emuldata thread & proc entries.
195	 */
196	if (SV_CURPROC_ABI() != SV_ABI_LINUX) {
197		PROC_LOCK(p);
198		em = em_find(td);
199		KASSERT(em != NULL, ("proc_exec: thread emuldata not found.\n"));
200		td->td_emuldata = NULL;
201
202		pem = pem_find(p);
203		KASSERT(pem != NULL, ("proc_exec: proc pemuldata not found.\n"));
204		p->p_emuldata = NULL;
205		PROC_UNLOCK(p);
206
207		if (pem->epoll != NULL) {
208			emd = pem->epoll;
209			pem->epoll = NULL;
210			free(emd, M_EPOLL);
211		}
212
213		free(em, M_TEMP);
214		free(pem, M_LINUX);
215	}
216	return (0);
217}
218
219void
220linux_proc_exec(void *arg __unused, struct proc *p, struct image_params *imgp)
221{
222	struct thread *td = curthread;
223
224	/*
225	 * In a case of execing to linux binary we create linux
226	 * emuldata thread entry.
227	 */
228	if (__predict_false((imgp->sysent->sv_flags & SV_ABI_MASK) ==
229	    SV_ABI_LINUX)) {
230
231		if (SV_PROC_ABI(p) == SV_ABI_LINUX)
232			linux_proc_init(td, NULL, 0);
233		else
234			linux_proc_init(td, td, 0);
235	}
236}
237
238void
239linux_thread_dtor(void *arg __unused, struct thread *td)
240{
241	struct linux_emuldata *em;
242
243	em = em_find(td);
244	if (em == NULL)
245		return;
246	td->td_emuldata = NULL;
247
248	LINUX_CTR1(exit, "thread dtor(%d)", em->em_tid);
249
250	free(em, M_TEMP);
251}
252
253void
254linux_schedtail(struct thread *td)
255{
256	struct linux_emuldata *em;
257	struct proc *p;
258	int error = 0;
259	int *child_set_tid;
260
261	p = td->td_proc;
262
263	em = em_find(td);
264	KASSERT(em != NULL, ("linux_schedtail: thread emuldata not found.\n"));
265	child_set_tid = em->child_set_tid;
266
267	if (child_set_tid != NULL) {
268		error = copyout(&em->em_tid, (int *)child_set_tid,
269		    sizeof(em->em_tid));
270		LINUX_CTR4(clone, "schedtail(%d) %p stored %d error %d",
271		    td->td_tid, child_set_tid, em->em_tid, error);
272	} else
273		LINUX_CTR1(clone, "schedtail(%d)", em->em_tid);
274}
275