lwproc.c revision 1.7 
1/*      $NetBSD: lwproc.c,v 1.7 2011/01/02 12:52:25 pooka Exp $	*/
2
3/*
4 * Copyright (c) 2010, 2011 Antti Kantee.  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 * 2. Redistributions in binary form must reproduce the above copyright
12 *    notice, this list of conditions and the following disclaimer in the
13 *    documentation and/or other materials provided with the distribution.
14 *
15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
16 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
17 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
18 * DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
19 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
20 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
21 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
22 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
23 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
24 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
25 * SUCH DAMAGE.
26 */
27
28#include <sys/cdefs.h>
29__KERNEL_RCSID(0, "$NetBSD: lwproc.c,v 1.7 2011/01/02 12:52:25 pooka Exp $");
30
31#include <sys/param.h>
32#include <sys/atomic.h>
33#include <sys/filedesc.h>
34#include <sys/kauth.h>
35#include <sys/kmem.h>
36#include <sys/lwp.h>
37#include <sys/pool.h>
38#include <sys/proc.h>
39#include <sys/queue.h>
40#include <sys/resourcevar.h>
41#include <sys/uidinfo.h>
42
43#include <rump/rumpuser.h>
44
45#include "rump_private.h"
46
47static void
48lwproc_proc_free(struct proc *p)
49{
50	kauth_cred_t cred;
51
52	mutex_enter(proc_lock);
53
54	KASSERT(p->p_nlwps == 0);
55	KASSERT(LIST_EMPTY(&p->p_lwps));
56	KASSERT(p->p_stat == SIDL || p->p_stat == SDEAD);
57
58	LIST_REMOVE(p, p_list);
59	LIST_REMOVE(p, p_sibling);
60	proc_free_pid(p->p_pid); /* decrements nprocs */
61	proc_leavepgrp(p); /* releases proc_lock */
62
63	cred = p->p_cred;
64	chgproccnt(kauth_cred_getuid(cred), -1);
65	if (rump_proc_vfs_release)
66		rump_proc_vfs_release(p);
67
68	limfree(p->p_limit);
69	pstatsfree(p->p_stats);
70	kauth_cred_free(p->p_cred);
71	proc_finispecific(p);
72
73	mutex_obj_free(p->p_lock);
74	mutex_destroy(&p->p_stmutex);
75	mutex_destroy(&p->p_auxlock);
76	rw_destroy(&p->p_reflock);
77	cv_destroy(&p->p_waitcv);
78	cv_destroy(&p->p_lwpcv);
79
80	/* non-kernel vmspaces are not shared */
81	if (p->p_vmspace != vmspace_kernel()) {
82		KASSERT(p->p_vmspace->vm_refcnt == 1);
83		kmem_free(p->p_vmspace, sizeof(*p->p_vmspace));
84	}
85
86	proc_free_mem(p);
87}
88
89/*
90 * Allocate a new process.  Mostly mimic fork by
91 * copying the properties of the parent.  However, there are some
92 * differences.  For example, we never share the fd table.
93 *
94 * Switch to the new lwp and return a pointer to it.
95 */
96static struct proc *
97lwproc_newproc(struct proc *parent, int flags)
98{
99	uid_t uid = kauth_cred_getuid(parent->p_cred);
100	struct proc *p;
101
102	/* maxproc not enforced */
103	atomic_inc_uint(&nprocs);
104
105	/* allocate process */
106	p = proc_alloc();
107	memset(&p->p_startzero, 0,
108	    offsetof(struct proc, p_endzero)
109	      - offsetof(struct proc, p_startzero));
110	memcpy(&p->p_startcopy, &parent->p_startcopy,
111	    offsetof(struct proc, p_endcopy)
112	      - offsetof(struct proc, p_startcopy));
113
114	p->p_stats = pstatscopy(parent->p_stats);
115
116	p->p_vmspace = vmspace_kernel();
117	p->p_emul = &emul_netbsd;
118
119	if ((flags & RUMP_RFCFDG) == 0)
120		KASSERT(parent == curproc);
121	if (flags & RUMP_RFFDG)
122		p->p_fd = fd_copy();
123	else if (flags & RUMP_RFCFDG)
124		p->p_fd = fd_init(NULL);
125	else
126		fd_share(p);
127
128	lim_addref(parent->p_limit);
129	p->p_limit = parent->p_limit;
130
131	LIST_INIT(&p->p_lwps);
132	LIST_INIT(&p->p_children);
133
134	p->p_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
135	mutex_init(&p->p_stmutex, MUTEX_DEFAULT, IPL_NONE);
136	mutex_init(&p->p_auxlock, MUTEX_DEFAULT, IPL_NONE);
137	rw_init(&p->p_reflock);
138	cv_init(&p->p_waitcv, "pwait");
139	cv_init(&p->p_lwpcv, "plwp");
140
141	p->p_pptr = parent;
142	p->p_ppid = parent->p_pid;
143
144	kauth_proc_fork(parent, p);
145
146	/* initialize cwd in rump kernels with vfs */
147	if (rump_proc_vfs_init)
148		rump_proc_vfs_init(p);
149
150	chgproccnt(uid, 1); /* not enforced */
151
152	/* publish proc various proc lists */
153	mutex_enter(proc_lock);
154	LIST_INSERT_HEAD(&allproc, p, p_list);
155	LIST_INSERT_HEAD(&parent->p_children, p, p_sibling);
156	LIST_INSERT_AFTER(parent, p, p_pglist);
157	mutex_exit(proc_lock);
158
159	return p;
160}
161
162static void
163lwproc_freelwp(struct lwp *l)
164{
165	struct proc *p;
166	bool freeproc;
167
168	p = l->l_proc;
169	mutex_enter(p->p_lock);
170
171	/* XXX: l_refcnt */
172	KASSERT(l->l_flag & LW_WEXIT);
173	KASSERT(l->l_refcnt == 0);
174
175	/* ok, zero references, continue with nuke */
176	LIST_REMOVE(l, l_sibling);
177	KASSERT(p->p_nlwps >= 1);
178	if (--p->p_nlwps == 0) {
179		KASSERT(p != &proc0);
180		p->p_stat = SDEAD;
181	}
182	freeproc = p->p_nlwps == 0;
183	cv_broadcast(&p->p_lwpcv); /* nobody sleeps on this in rump? */
184	kauth_cred_free(l->l_cred);
185	mutex_exit(p->p_lock);
186
187	mutex_enter(proc_lock);
188	LIST_REMOVE(l, l_list);
189	mutex_exit(proc_lock);
190
191	if (l->l_name)
192		kmem_free(l->l_name, MAXCOMLEN);
193	lwp_finispecific(l);
194
195	kmem_free(l, sizeof(*l));
196
197	if (p->p_stat == SDEAD)
198		lwproc_proc_free(p);
199}
200
201/*
202 * called with p_lock held, releases lock before return
203 */
204static void
205lwproc_makelwp(struct proc *p, struct lwp *l, bool doswitch, bool procmake)
206{
207
208	p->p_nlwps++;
209	l->l_refcnt = 1;
210	l->l_proc = p;
211
212	l->l_lid = p->p_nlwpid++;
213	LIST_INSERT_HEAD(&p->p_lwps, l, l_sibling);
214	mutex_exit(p->p_lock);
215
216	lwp_update_creds(l);
217
218	l->l_fd = p->p_fd;
219	l->l_cpu = NULL;
220	l->l_target_cpu = rump_cpu; /* Initial target CPU always the same */
221
222	lwp_initspecific(l);
223
224	if (doswitch) {
225		rump_lwproc_switch(l);
226	}
227
228	/* filedesc already has refcount 1 when process is created */
229	if (!procmake) {
230		fd_hold(l);
231	}
232
233	mutex_enter(proc_lock);
234	LIST_INSERT_HEAD(&alllwp, l, l_list);
235	mutex_exit(proc_lock);
236}
237
238struct lwp *
239rump__lwproc_alloclwp(struct proc *p)
240{
241	struct lwp *l;
242	bool newproc = false;
243
244	if (p == NULL) {
245		p = lwproc_newproc(&proc0, 0);
246		newproc = true;
247	}
248
249	l = kmem_zalloc(sizeof(*l), KM_SLEEP);
250
251	mutex_enter(p->p_lock);
252	lwproc_makelwp(p, l, false, newproc);
253
254	return l;
255}
256
257int
258rump_lwproc_newlwp(pid_t pid)
259{
260	struct proc *p;
261	struct lwp *l;
262
263	l = kmem_zalloc(sizeof(*l), KM_SLEEP);
264	mutex_enter(proc_lock);
265	p = proc_find_raw(pid);
266	if (p == NULL) {
267		mutex_exit(proc_lock);
268		kmem_free(l, sizeof(*l));
269		return ESRCH;
270	}
271	mutex_enter(p->p_lock);
272	mutex_exit(proc_lock);
273	lwproc_makelwp(p, l, true, false);
274
275	return 0;
276}
277
278int
279rump_lwproc_rfork(int flags)
280{
281	struct proc *p;
282	struct lwp *l;
283
284	if (flags & ~(RUMP_RFFDG|RUMP_RFCFDG) ||
285	    (~flags & (RUMP_RFFDG|RUMP_RFCFDG)) == 0)
286		return EINVAL;
287
288	p = lwproc_newproc(curproc, flags);
289	l = kmem_zalloc(sizeof(*l), KM_SLEEP);
290	mutex_enter(p->p_lock);
291	lwproc_makelwp(p, l, true, true);
292
293	return 0;
294}
295
296/*
297 * Switch to a new process/thread.  Release previous one if
298 * deemed to be exiting.  This is considered a slow path for
299 * rump kernel entry.
300 */
301void
302rump_lwproc_switch(struct lwp *newlwp)
303{
304	struct lwp *l = curlwp;
305
306	KASSERT(!(l->l_flag & LW_WEXIT) || newlwp);
307
308	if (__predict_false(newlwp && (newlwp->l_pflag & LP_RUNNING)))
309		panic("lwp %p (%d:%d) already running",
310		    newlwp, newlwp->l_proc->p_pid, newlwp->l_lid);
311
312	if (newlwp == NULL) {
313		l->l_pflag &= ~LP_RUNNING;
314		l->l_flag |= LW_RUMP_CLEAR;
315		return;
316	}
317
318	/* fd_free() must be called from curlwp context.  talk about ugh */
319	if (l->l_flag & LW_WEXIT) {
320		fd_free();
321	}
322
323	rumpuser_set_curlwp(NULL);
324
325	newlwp->l_cpu = newlwp->l_target_cpu = l->l_cpu;
326	newlwp->l_mutex = l->l_mutex;
327	newlwp->l_pflag |= LP_RUNNING;
328
329	rumpuser_set_curlwp(newlwp);
330
331	/*
332	 * Check if the thread should get a signal.  This is
333	 * mostly to satisfy the "record" rump sigmodel.
334	 */
335	mutex_enter(newlwp->l_proc->p_lock);
336	if (sigispending(newlwp, 0)) {
337		newlwp->l_flag |= LW_PENDSIG;
338	}
339	mutex_exit(newlwp->l_proc->p_lock);
340
341	l->l_mutex = NULL;
342	l->l_cpu = NULL;
343	l->l_pflag &= ~LP_RUNNING;
344	l->l_flag &= ~LW_PENDSIG;
345
346	if (l->l_flag & LW_WEXIT) {
347		lwproc_freelwp(l);
348	}
349}
350
351void
352rump_lwproc_releaselwp(void)
353{
354	struct proc *p;
355	struct lwp *l = curlwp;
356
357	if (l->l_refcnt == 0 && l->l_flag & LW_WEXIT)
358		panic("releasing non-pertinent lwp");
359
360	p = l->l_proc;
361	mutex_enter(p->p_lock);
362	KASSERT(l->l_refcnt != 0);
363	l->l_refcnt--;
364	mutex_exit(p->p_lock);
365	l->l_flag |= LW_WEXIT; /* will be released when unscheduled */
366}
367
368struct lwp *
369rump_lwproc_curlwp(void)
370{
371	struct lwp *l = curlwp;
372
373	if (l->l_flag & LW_WEXIT)
374		return NULL;
375	return l;
376}
377