linux_emul.c revision 293558 
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 293558 2016-01-09 17:02:35Z 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		if (flags & LINUX_CLONE_THREAD) {
93			LINUX_CTR1(proc_init, "thread newtd(%d)",
94			    newtd->td_tid);
95
96			em->em_tid = newtd->td_tid;
97		} else {
98			LINUX_CTR1(proc_init, "fork newtd(%d)",
99			    newtd->td_proc->p_pid);
100
101			em->em_tid = newtd->td_proc->p_pid;
102
103			pem = malloc(sizeof(*pem), M_LINUX, M_WAITOK | M_ZERO);
104			sx_init(&pem->pem_sx, "lpemlk");
105			newtd->td_proc->p_emuldata = pem;
106		}
107		newtd->td_emuldata = em;
108	} else {
109		/* exec */
110		LINUX_CTR1(proc_init, "exec newtd(%d)",
111		    td->td_proc->p_pid);
112
113		/* lookup the old one */
114		em = em_find(td);
115		KASSERT(em != NULL, ("proc_init: emuldata not found in exec case.\n"));
116
117		em->em_tid = td->td_proc->p_pid;
118		em->flags = 0;
119		em->pdeath_signal = 0;
120		em->robust_futexes = NULL;
121		em->child_clear_tid = NULL;
122		em->child_set_tid = NULL;
123
124		 /* epoll should be destroyed in a case of exec. */
125		pem = pem_find(td->td_proc);
126		KASSERT(pem != NULL, ("proc_exit: proc emuldata not found.\n"));
127
128		if (pem->epoll != NULL) {
129			emd = pem->epoll;
130			pem->epoll = NULL;
131			free(emd, M_EPOLL);
132		}
133	}
134
135}
136
137void
138linux_proc_exit(void *arg __unused, struct proc *p)
139{
140	struct linux_pemuldata *pem;
141	struct epoll_emuldata *emd;
142	struct thread *td = curthread;
143
144	if (__predict_false(SV_CURPROC_ABI() != SV_ABI_LINUX))
145		return;
146
147	pem = pem_find(p);
148	if (pem == NULL)
149		return;
150	(p->p_sysent->sv_thread_detach)(td);
151
152	p->p_emuldata = NULL;
153
154	if (pem->epoll != NULL) {
155		emd = pem->epoll;
156		pem->epoll = NULL;
157		free(emd, M_EPOLL);
158	}
159
160	sx_destroy(&pem->pem_sx);
161	free(pem, M_LINUX);
162}
163
164int
165linux_common_execve(struct thread *td, struct image_args *eargs)
166{
167	struct linux_pemuldata *pem;
168	struct epoll_emuldata *emd;
169	struct linux_emuldata *em;
170	struct proc *p;
171	int error;
172
173	p = td->td_proc;
174
175	/*
176	 * Unlike FreeBSD abort all other threads before
177	 * proceeding exec.
178	 */
179	PROC_LOCK(p);
180	/* See exit1() comments. */
181	thread_suspend_check(0);
182	while (p->p_flag & P_HADTHREADS) {
183		if (!thread_single(p, SINGLE_EXIT))
184			break;
185		thread_suspend_check(0);
186	}
187	PROC_UNLOCK(p);
188
189	error = kern_execve(td, eargs, NULL);
190	if (error != 0)
191		return (error);
192
193	/*
194	 * In a case of transition from Linux binary execing to
195	 * FreeBSD binary we destroy linux emuldata thread & proc entries.
196	 */
197	if (SV_CURPROC_ABI() != SV_ABI_LINUX) {
198		PROC_LOCK(p);
199		em = em_find(td);
200		KASSERT(em != NULL, ("proc_exec: thread emuldata not found.\n"));
201		td->td_emuldata = NULL;
202
203		pem = pem_find(p);
204		KASSERT(pem != NULL, ("proc_exec: proc pemuldata not found.\n"));
205		p->p_emuldata = NULL;
206		PROC_UNLOCK(p);
207
208		if (pem->epoll != NULL) {
209			emd = pem->epoll;
210			pem->epoll = NULL;
211			free(emd, M_EPOLL);
212		}
213
214		free(em, M_TEMP);
215		free(pem, M_LINUX);
216	}
217	return (0);
218}
219
220void
221linux_proc_exec(void *arg __unused, struct proc *p, struct image_params *imgp)
222{
223	struct thread *td = curthread;
224
225	/*
226	 * In a case of execing to linux binary we create linux
227	 * emuldata thread entry.
228	 */
229	if (__predict_false((imgp->sysent->sv_flags & SV_ABI_MASK) ==
230	    SV_ABI_LINUX)) {
231
232		if (SV_PROC_ABI(p) == SV_ABI_LINUX)
233			linux_proc_init(td, NULL, 0);
234		else
235			linux_proc_init(td, td, 0);
236	}
237}
238
239void
240linux_thread_dtor(void *arg __unused, struct thread *td)
241{
242	struct linux_emuldata *em;
243
244	em = em_find(td);
245	if (em == NULL)
246		return;
247	td->td_emuldata = NULL;
248
249	LINUX_CTR1(exit, "thread dtor(%d)", em->em_tid);
250
251	free(em, M_TEMP);
252}
253
254void
255linux_schedtail(struct thread *td)
256{
257	struct linux_emuldata *em;
258	struct proc *p;
259	int error = 0;
260	int *child_set_tid;
261
262	p = td->td_proc;
263
264	em = em_find(td);
265	KASSERT(em != NULL, ("linux_schedtail: thread emuldata not found.\n"));
266	child_set_tid = em->child_set_tid;
267
268	if (child_set_tid != NULL) {
269		error = copyout(&em->em_tid, child_set_tid,
270		    sizeof(em->em_tid));
271		LINUX_CTR4(clone, "schedtail(%d) %p stored %d error %d",
272		    td->td_tid, child_set_tid, em->em_tid, error);
273	} else
274		LINUX_CTR1(clone, "schedtail(%d)", em->em_tid);
275}
276