linux_emul.c revision 293560 
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 293560 2016-01-09 17:05:00Z 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	struct proc *p;
89
90	if (newtd != NULL) {
91		p = newtd->td_proc;
92
93		/* non-exec call */
94		em = malloc(sizeof(*em), M_TEMP, M_WAITOK | M_ZERO);
95		if (flags & LINUX_CLONE_THREAD) {
96			LINUX_CTR1(proc_init, "thread newtd(%d)",
97			    newtd->td_tid);
98
99			em->em_tid = newtd->td_tid;
100		} else {
101			LINUX_CTR1(proc_init, "fork newtd(%d)", p->p_pid);
102
103			em->em_tid = p->p_pid;
104
105			pem = malloc(sizeof(*pem), M_LINUX, M_WAITOK | M_ZERO);
106			sx_init(&pem->pem_sx, "lpemlk");
107			p->p_emuldata = pem;
108		}
109		newtd->td_emuldata = em;
110	} else {
111		p = td->td_proc;
112
113		/* exec */
114		LINUX_CTR1(proc_init, "exec newtd(%d)", p->p_pid);
115
116		/* lookup the old one */
117		em = em_find(td);
118		KASSERT(em != NULL, ("proc_init: emuldata not found in exec case.\n"));
119
120		em->em_tid = p->p_pid;
121		em->flags = 0;
122		em->pdeath_signal = 0;
123		em->robust_futexes = NULL;
124		em->child_clear_tid = NULL;
125		em->child_set_tid = NULL;
126
127		 /* epoll should be destroyed in a case of exec. */
128		pem = pem_find(p);
129		KASSERT(pem != NULL, ("proc_exit: proc emuldata not found.\n"));
130
131		if (pem->epoll != NULL) {
132			emd = pem->epoll;
133			pem->epoll = NULL;
134			free(emd, M_EPOLL);
135		}
136	}
137
138}
139
140void
141linux_proc_exit(void *arg __unused, struct proc *p)
142{
143	struct linux_pemuldata *pem;
144	struct epoll_emuldata *emd;
145	struct thread *td = curthread;
146
147	if (__predict_false(SV_CURPROC_ABI() != SV_ABI_LINUX))
148		return;
149
150	LINUX_CTR3(proc_exit, "thread(%d) proc(%d) p %p",
151	    td->td_tid, p->p_pid, p);
152
153	pem = pem_find(p);
154	if (pem == NULL)
155		return;
156	(p->p_sysent->sv_thread_detach)(td);
157
158	p->p_emuldata = NULL;
159
160	if (pem->epoll != NULL) {
161		emd = pem->epoll;
162		pem->epoll = NULL;
163		free(emd, M_EPOLL);
164	}
165
166	sx_destroy(&pem->pem_sx);
167	free(pem, M_LINUX);
168}
169
170int
171linux_common_execve(struct thread *td, struct image_args *eargs)
172{
173	struct linux_pemuldata *pem;
174	struct epoll_emuldata *emd;
175	struct linux_emuldata *em;
176	struct proc *p;
177	int error;
178
179	p = td->td_proc;
180
181	/*
182	 * Unlike FreeBSD abort all other threads before
183	 * proceeding exec.
184	 */
185	PROC_LOCK(p);
186	/* See exit1() comments. */
187	thread_suspend_check(0);
188	while (p->p_flag & P_HADTHREADS) {
189		if (!thread_single(p, SINGLE_EXIT))
190			break;
191		thread_suspend_check(0);
192	}
193	PROC_UNLOCK(p);
194
195	error = kern_execve(td, eargs, NULL);
196	if (error != 0)
197		return (error);
198
199	/*
200	 * In a case of transition from Linux binary execing to
201	 * FreeBSD binary we destroy linux emuldata thread & proc entries.
202	 */
203	if (SV_CURPROC_ABI() != SV_ABI_LINUX) {
204		PROC_LOCK(p);
205		em = em_find(td);
206		KASSERT(em != NULL, ("proc_exec: thread emuldata not found.\n"));
207		td->td_emuldata = NULL;
208
209		pem = pem_find(p);
210		KASSERT(pem != NULL, ("proc_exec: proc pemuldata not found.\n"));
211		p->p_emuldata = NULL;
212		PROC_UNLOCK(p);
213
214		if (pem->epoll != NULL) {
215			emd = pem->epoll;
216			pem->epoll = NULL;
217			free(emd, M_EPOLL);
218		}
219
220		free(em, M_TEMP);
221		free(pem, M_LINUX);
222	}
223	return (0);
224}
225
226void
227linux_proc_exec(void *arg __unused, struct proc *p, struct image_params *imgp)
228{
229	struct thread *td = curthread;
230
231	/*
232	 * In a case of execing to linux binary we create linux
233	 * emuldata thread entry.
234	 */
235	if (__predict_false((imgp->sysent->sv_flags & SV_ABI_MASK) ==
236	    SV_ABI_LINUX)) {
237
238		if (SV_PROC_ABI(p) == SV_ABI_LINUX)
239			linux_proc_init(td, NULL, 0);
240		else
241			linux_proc_init(td, td, 0);
242	}
243}
244
245void
246linux_thread_dtor(void *arg __unused, struct thread *td)
247{
248	struct linux_emuldata *em;
249
250	em = em_find(td);
251	if (em == NULL)
252		return;
253	td->td_emuldata = NULL;
254
255	LINUX_CTR1(thread_dtor, "thread(%d)", em->em_tid);
256
257	free(em, M_TEMP);
258}
259
260void
261linux_schedtail(struct thread *td)
262{
263	struct linux_emuldata *em;
264	struct proc *p;
265	int error = 0;
266	int *child_set_tid;
267
268	p = td->td_proc;
269
270	em = em_find(td);
271	KASSERT(em != NULL, ("linux_schedtail: thread emuldata not found.\n"));
272	child_set_tid = em->child_set_tid;
273
274	if (child_set_tid != NULL) {
275		error = copyout(&em->em_tid, child_set_tid,
276		    sizeof(em->em_tid));
277		LINUX_CTR4(schedtail, "thread(%d) %p stored %d error %d",
278		    td->td_tid, child_set_tid, em->em_tid, error);
279	} else
280		LINUX_CTR1(schedtail, "thread(%d)", em->em_tid);
281}
282