linux_emul.c revision 293532 
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 293532 2016-01-09 16:20:29Z 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#include <sys/sysproto.h>
46#include <sys/unistd.h>
47
48#include <compat/linux/linux_emul.h>
49#include <compat/linux/linux_misc.h>
50#include <compat/linux/linux_util.h>
51
52
53/*
54 * This returns reference to the thread emuldata entry (if found)
55 *
56 * Hold PROC_LOCK when referencing emuldata from other threads.
57 */
58struct linux_emuldata *
59em_find(struct thread *td)
60{
61	struct linux_emuldata *em;
62
63	em = td->td_emuldata;
64
65	return (em);
66}
67
68/*
69 * This returns reference to the proc pemuldata entry (if found)
70 *
71 * Hold PROC_LOCK when referencing proc pemuldata from other threads.
72 * Hold LINUX_PEM_LOCK wher referencing pemuldata members.
73 */
74struct linux_pemuldata *
75pem_find(struct proc *p)
76{
77	struct linux_pemuldata *pem;
78
79	pem = p->p_emuldata;
80
81	return (pem);
82}
83
84void
85linux_proc_init(struct thread *td, struct thread *newtd, int flags)
86{
87	struct linux_emuldata *em;
88	struct linux_pemuldata *pem;
89
90	if (newtd != NULL) {
91		/* non-exec call */
92		em = malloc(sizeof(*em), M_TEMP, M_WAITOK | M_ZERO);
93		em->pdeath_signal = 0;
94		em->robust_futexes = NULL;
95		if (flags & LINUX_CLONE_THREAD) {
96			em->em_tid = newtd->td_tid;
97		} else {
98
99			em->em_tid = newtd->td_proc->p_pid;
100
101			pem = malloc(sizeof(*pem), M_LINUX, M_WAITOK | M_ZERO);
102			sx_init(&pem->pem_sx, "lpemlk");
103			newtd->td_proc->p_emuldata = pem;
104		}
105		newtd->td_emuldata = em;
106	} else {
107		/* exec */
108
109		/* lookup the old one */
110		em = em_find(td);
111		KASSERT(em != NULL, ("proc_init: emuldata not found in exec case.\n"));
112
113		em->em_tid = td->td_proc->p_pid;
114	}
115
116	em->child_clear_tid = NULL;
117	em->child_set_tid = NULL;
118}
119
120void
121linux_proc_exit(void *arg __unused, struct proc *p)
122{
123	struct linux_pemuldata *pem;
124	struct thread *td = curthread;
125
126	if (__predict_false(SV_CURPROC_ABI() != SV_ABI_LINUX))
127		return;
128
129	pem = pem_find(p);
130	if (pem == NULL)
131		return;
132	(p->p_sysent->sv_thread_detach)(td);
133
134	p->p_emuldata = NULL;
135
136	sx_destroy(&pem->pem_sx);
137	free(pem, M_LINUX);
138}
139
140int
141linux_common_execve(struct thread *td, struct image_args *eargs)
142{
143	struct linux_pemuldata *pem;
144	struct linux_emuldata *em;
145	struct proc *p;
146	int error;
147
148	p = td->td_proc;
149
150	/*
151	 * Unlike FreeBSD abort all other threads before
152	 * proceeding exec.
153	 */
154	PROC_LOCK(p);
155	/* See exit1() comments. */
156	thread_suspend_check(0);
157	while (p->p_flag & P_HADTHREADS) {
158		if (!thread_single(p, SINGLE_EXIT))
159			break;
160		thread_suspend_check(0);
161	}
162	PROC_UNLOCK(p);
163
164	error = kern_execve(td, eargs, NULL);
165	if (error != 0)
166		return (error);
167
168	/*
169	 * In a case of transition from Linux binary execing to
170	 * FreeBSD binary we destroy linux emuldata thread & proc entries.
171	 */
172	if (SV_CURPROC_ABI() != SV_ABI_LINUX) {
173		PROC_LOCK(p);
174		em = em_find(td);
175		KASSERT(em != NULL, ("proc_exec: thread emuldata not found.\n"));
176		td->td_emuldata = NULL;
177
178		pem = pem_find(p);
179		KASSERT(pem != NULL, ("proc_exec: proc pemuldata not found.\n"));
180		p->p_emuldata = NULL;
181		PROC_UNLOCK(p);
182
183		free(em, M_TEMP);
184		free(pem, M_LINUX);
185	}
186	return (0);
187}
188
189void
190linux_proc_exec(void *arg __unused, struct proc *p, struct image_params *imgp)
191{
192	struct thread *td = curthread;
193
194	/*
195	 * In a case of execing to linux binary we create linux
196	 * emuldata thread entry.
197	 */
198	if (__predict_false((imgp->sysent->sv_flags & SV_ABI_MASK) ==
199	    SV_ABI_LINUX)) {
200		if (SV_PROC_ABI(p) == SV_ABI_LINUX)
201			linux_proc_init(td, NULL, 0);
202		else
203			linux_proc_init(td, td, 0);
204	}
205}
206
207void
208linux_thread_dtor(void *arg __unused, struct thread *td)
209{
210	struct linux_emuldata *em;
211
212	em = em_find(td);
213	if (em == NULL)
214		return;
215	td->td_emuldata = NULL;
216
217	LINUX_CTR1(exit, "thread dtor(%d)", em->em_tid);
218
219	free(em, M_TEMP);
220}
221
222void
223linux_schedtail(struct thread *td)
224{
225	struct linux_emuldata *em;
226	struct proc *p;
227	int error = 0;
228	int *child_set_tid;
229
230	p = td->td_proc;
231
232	em = em_find(td);
233	KASSERT(em != NULL, ("linux_schedtail: thread emuldata not found.\n"));
234	child_set_tid = em->child_set_tid;
235
236	if (child_set_tid != NULL) {
237		error = copyout(&em->em_tid, (int *)child_set_tid,
238		    sizeof(em->em_tid));
239		LINUX_CTR4(clone, "schedtail(%d) %p stored %d error %d",
240		    td->td_tid, child_set_tid, em->em_tid, error);
241	} else
242		LINUX_CTR1(clone, "schedtail(%d)", em->em_tid);
243}
244