lwproc.c revision 1.51 
1/*      $NetBSD: lwproc.c,v 1.51 2020/05/30 19:16:53 ad 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#define RUMP__CURLWP_PRIVATE
29
30#include <sys/cdefs.h>
31__KERNEL_RCSID(0, "$NetBSD: lwproc.c,v 1.51 2020/05/30 19:16:53 ad Exp $");
32
33#include <sys/param.h>
34#include <sys/atomic.h>
35#include <sys/filedesc.h>
36#include <sys/fstrans.h>
37#include <sys/kauth.h>
38#include <sys/kmem.h>
39#include <sys/lwp.h>
40#include <sys/ktrace.h>
41#include <sys/pool.h>
42#include <sys/proc.h>
43#include <sys/queue.h>
44#include <sys/resourcevar.h>
45#include <sys/uidinfo.h>
46#include <sys/psref.h>
47
48#include <rump-sys/kern.h>
49
50#include <rump/rumpuser.h>
51
52#include "rump_curlwp.h"
53
54struct lwp lwp0 = {
55	.l_lid = 0,
56	.l_proc = &proc0,
57	.l_fd = &filedesc0,
58};
59struct lwplist alllwp = LIST_HEAD_INITIALIZER(alllwp);
60
61u_int nprocs = 1;
62
63struct emul *emul_default = &emul_netbsd;
64
65void
66lwp_unsleep(lwp_t *l, bool cleanup)
67{
68
69	KASSERT(mutex_owned(l->l_mutex));
70
71	(*l->l_syncobj->sobj_unsleep)(l, cleanup);
72}
73
74/*
75 * Look up a live LWP within the specified process.
76 *
77 * Must be called with p->p_lock held.
78 */
79struct lwp *
80lwp_find(struct proc *p, lwpid_t id)
81{
82	struct lwp *l;
83
84	KASSERT(mutex_owned(p->p_lock));
85
86	LIST_FOREACH(l, &p->p_lwps, l_sibling) {
87		if (l->l_lid == id)
88			break;
89	}
90
91	/*
92	 * No need to lock - all of these conditions will
93	 * be visible with the process level mutex held.
94	 */
95	if (l != NULL && (l->l_stat == LSIDL || l->l_stat == LSZOMB))
96		l = NULL;
97
98	return l;
99}
100
101void
102lwp_update_creds(struct lwp *l)
103{
104	struct proc *p;
105	kauth_cred_t oldcred;
106
107	p = l->l_proc;
108	oldcred = l->l_cred;
109	l->l_prflag &= ~LPR_CRMOD;
110
111	mutex_enter(p->p_lock);
112	kauth_cred_hold(p->p_cred);
113	l->l_cred = p->p_cred;
114	mutex_exit(p->p_lock);
115
116	if (oldcred != NULL)
117		kauth_cred_free(oldcred);
118}
119
120void
121rump_lwproc_init(void)
122{
123
124	lwproc_curlwpop(RUMPUSER_LWP_CREATE, &lwp0);
125}
126
127struct lwp *
128rump_lwproc_curlwp_hypercall(void)
129{
130
131	return rumpuser_curlwp();
132}
133
134void
135rump_lwproc_curlwp_set(struct lwp *l)
136{
137
138	KASSERT(curlwp == NULL);
139	lwproc_curlwpop(RUMPUSER_LWP_SET, l);
140}
141
142void
143rump_lwproc_curlwp_clear(struct lwp *l)
144{
145
146	KASSERT(l == curlwp);
147	lwproc_curlwpop(RUMPUSER_LWP_CLEAR, l);
148}
149
150static void
151lwproc_proc_free(struct proc *p)
152{
153	kauth_cred_t cred;
154	struct proc *child;
155
156	KASSERT(p->p_stat == SDYING || p->p_stat == SDEAD);
157
158#ifdef KTRACE
159	if (p->p_tracep) {
160		mutex_enter(&ktrace_lock);
161		ktrderef(p);
162		mutex_exit(&ktrace_lock);
163	}
164#endif
165
166	mutex_enter(&proc_lock);
167
168	/* childranee eunt initus */
169	while ((child = LIST_FIRST(&p->p_children)) != NULL) {
170		LIST_REMOVE(child, p_sibling);
171		child->p_pptr = initproc;
172		child->p_ppid = 1;
173		LIST_INSERT_HEAD(&initproc->p_children, child, p_sibling);
174	}
175
176	KASSERT(p->p_nlwps == 0);
177	KASSERT(LIST_EMPTY(&p->p_lwps));
178
179	LIST_REMOVE(p, p_list);
180	LIST_REMOVE(p, p_sibling);
181	proc_free_pid(p->p_pid);
182	atomic_dec_uint(&nprocs);
183	proc_leavepgrp(p); /* releases proc_lock */
184
185	cred = p->p_cred;
186	chgproccnt(kauth_cred_getuid(cred), -1);
187	rump_proc_vfs_release(p);
188
189	doexithooks(p);
190	lim_free(p->p_limit);
191	pstatsfree(p->p_stats);
192	kauth_cred_free(p->p_cred);
193	proc_finispecific(p);
194
195	mutex_obj_free(p->p_lock);
196	mutex_destroy(&p->p_stmutex);
197	mutex_destroy(&p->p_auxlock);
198	rw_destroy(&p->p_reflock);
199	cv_destroy(&p->p_waitcv);
200	cv_destroy(&p->p_lwpcv);
201
202	/* non-local vmspaces are not shared */
203	if (!RUMP_LOCALPROC_P(p)) {
204		struct rump_spctl *ctl = (struct rump_spctl *)p->p_vmspace;
205		KASSERT(p->p_vmspace->vm_refcnt == 1);
206		kmem_free(ctl, sizeof(*ctl));
207	}
208
209	proc_free_mem(p);
210}
211
212/*
213 * Allocate a new process.  Mostly mimic fork by
214 * copying the properties of the parent.  However, there are some
215 * differences.
216 *
217 * Switch to the new lwp and return a pointer to it.
218 */
219static struct proc *
220lwproc_newproc(struct proc *parent, struct vmspace *vm, int flags)
221{
222	uid_t uid = kauth_cred_getuid(parent->p_cred);
223	struct proc *p;
224
225	/* maxproc not enforced */
226	atomic_inc_uint(&nprocs);
227
228	/* allocate process */
229	p = proc_alloc();
230	memset(&p->p_startzero, 0,
231	    offsetof(struct proc, p_endzero)
232	      - offsetof(struct proc, p_startzero));
233	memcpy(&p->p_startcopy, &parent->p_startcopy,
234	    offsetof(struct proc, p_endcopy)
235	      - offsetof(struct proc, p_startcopy));
236
237	/* some other garbage we need to zero */
238	p->p_sigacts = NULL;
239	p->p_aio = NULL;
240	p->p_dtrace = NULL;
241	p->p_mqueue_cnt = p->p_exitsig = 0;
242	p->p_flag = p->p_sflag = p->p_slflag = p->p_lflag = p->p_stflag = 0;
243	p->p_trace_enabled = 0;
244	p->p_xsig = p->p_xexit = p->p_acflag = 0;
245	p->p_stackbase = 0;
246
247	p->p_stats = pstatscopy(parent->p_stats);
248
249	p->p_vmspace = vm;
250	p->p_emul = emul_default;
251#ifdef __HAVE_SYSCALL_INTERN
252	p->p_emul->e_syscall_intern(p);
253#endif
254	if (*parent->p_comm)
255		strcpy(p->p_comm, parent->p_comm);
256	else
257		strcpy(p->p_comm, "rumproc");
258
259	if ((flags & RUMP_RFCFDG) == 0)
260		KASSERT(parent == curproc);
261	if (flags & RUMP_RFFDG)
262		p->p_fd = fd_copy();
263	else if (flags & RUMP_RFCFDG)
264		p->p_fd = fd_init(NULL);
265	else
266		fd_share(p);
267
268	lim_addref(parent->p_limit);
269	p->p_limit = parent->p_limit;
270
271	LIST_INIT(&p->p_lwps);
272	LIST_INIT(&p->p_children);
273
274	p->p_lock = mutex_obj_alloc(MUTEX_DEFAULT, IPL_NONE);
275	mutex_init(&p->p_stmutex, MUTEX_DEFAULT, IPL_HIGH);
276	mutex_init(&p->p_auxlock, MUTEX_DEFAULT, IPL_NONE);
277	rw_init(&p->p_reflock);
278	cv_init(&p->p_waitcv, "pwait");
279	cv_init(&p->p_lwpcv, "plwp");
280
281	p->p_pptr = parent;
282	p->p_ppid = parent->p_pid;
283	p->p_stat = SACTIVE;
284
285	kauth_proc_fork(parent, p);
286
287	/* initialize cwd in rump kernels with vfs */
288	rump_proc_vfs_init(p);
289
290	chgproccnt(uid, 1); /* not enforced */
291
292	/* publish proc various proc lists */
293	mutex_enter(&proc_lock);
294	LIST_INSERT_HEAD(&allproc, p, p_list);
295	LIST_INSERT_HEAD(&parent->p_children, p, p_sibling);
296	LIST_INSERT_AFTER(parent, p, p_pglist);
297	mutex_exit(&proc_lock);
298
299	return p;
300}
301
302static void
303lwproc_freelwp(struct lwp *l)
304{
305	struct proc *p;
306
307	p = l->l_proc;
308	mutex_enter(p->p_lock);
309
310	KASSERT(l->l_flag & LW_WEXIT);
311	KASSERT(l->l_refcnt == 0);
312
313	LIST_REMOVE(l, l_sibling);
314	KASSERT(p->p_nlwps >= 1);
315	if (--p->p_nlwps == 0) {
316		KASSERT(p != &proc0);
317		p->p_stat = SDEAD;
318	} else {
319		chglwpcnt(kauth_cred_getuid(p->p_cred), -1);
320	}
321	cv_broadcast(&p->p_lwpcv); /* nobody sleeps on this in a rump kernel? */
322	kauth_cred_free(l->l_cred);
323	l->l_stat = LSIDL;
324	mutex_exit(p->p_lock);
325
326	mutex_enter(&proc_lock);
327	proc_free_lwpid(p, l->l_lid);
328	LIST_REMOVE(l, l_list);
329	mutex_exit(&proc_lock);
330
331	if (l->l_name)
332		kmem_free(l->l_name, MAXCOMLEN);
333	fstrans_lwp_dtor(l);
334	lwp_finispecific(l);
335
336	lwproc_curlwpop(RUMPUSER_LWP_DESTROY, l);
337	membar_exit();
338	kmem_free(l, sizeof(*l));
339
340	if (p->p_stat == SDEAD)
341		lwproc_proc_free(p);
342}
343
344extern kmutex_t unruntime_lock;
345
346static struct lwp *
347lwproc_makelwp(struct proc *p, bool doswitch, bool procmake)
348{
349	struct lwp *l = kmem_zalloc(sizeof(*l), KM_SLEEP);
350
351	/*
352	 * Account the new lwp to the owner of the process.
353	 * For some reason, NetBSD doesn't count the first lwp
354	 * in a process as a lwp, so skip that.
355	 */
356	if (p->p_nlwps++) {
357		chglwpcnt(kauth_cred_getuid(p->p_cred), 1);
358	}
359
360	l->l_refcnt = 1;
361	l->l_proc = p;
362	l->l_stat = LSIDL;
363	l->l_mutex = &unruntime_lock;
364
365	proc_alloc_lwpid(p, l);
366
367	mutex_enter(p->p_lock);
368	KASSERT((p->p_sflag & PS_RUMP_LWPEXIT) == 0);
369	LIST_INSERT_HEAD(&p->p_lwps, l, l_sibling);
370
371	l->l_fd = p->p_fd;
372	l->l_cpu = &rump_bootcpu;
373	l->l_target_cpu = &rump_bootcpu; /* Initial target CPU always same */
374	l->l_stat = LSRUN;
375	TAILQ_INIT(&l->l_ld_locks);
376	mutex_exit(p->p_lock);
377
378	lwp_update_creds(l);
379	lwp_initspecific(l);
380	PSREF_DEBUG_INIT_LWP(l);
381
382	membar_enter();
383	lwproc_curlwpop(RUMPUSER_LWP_CREATE, l);
384	if (doswitch) {
385		rump_lwproc_switch(l);
386	}
387
388	/* filedesc already has refcount 1 when process is created */
389	if (!procmake) {
390		fd_hold(l);
391	}
392
393	mutex_enter(&proc_lock);
394	LIST_INSERT_HEAD(&alllwp, l, l_list);
395	mutex_exit(&proc_lock);
396
397	return l;
398}
399
400struct lwp *
401rump__lwproc_alloclwp(struct proc *p)
402{
403	bool newproc = false;
404
405	if (p == NULL) {
406		p = lwproc_newproc(&proc0, rump_vmspace_local, RUMP_RFCFDG);
407		newproc = true;
408	}
409
410	return lwproc_makelwp(p, false, newproc);
411}
412
413int
414rump_lwproc_newlwp(pid_t pid)
415{
416	struct proc *p;
417	struct lwp *l;
418
419	l = kmem_zalloc(sizeof(*l), KM_SLEEP);
420	mutex_enter(&proc_lock);
421	p = proc_find_raw(pid);
422	if (p == NULL) {
423		mutex_exit(&proc_lock);
424		kmem_free(l, sizeof(*l));
425		return ESRCH;
426	}
427	mutex_enter(p->p_lock);
428	if (p->p_sflag & PS_RUMP_LWPEXIT) {
429		mutex_exit(&proc_lock);
430		mutex_exit(p->p_lock);
431		kmem_free(l, sizeof(*l));
432		return EBUSY;
433	}
434	mutex_exit(p->p_lock);
435	mutex_exit(&proc_lock);
436
437	/* XXX what holds proc? */
438
439	lwproc_makelwp(p, true, false);
440
441	return 0;
442}
443
444int
445rump_lwproc_rfork_vmspace(struct vmspace *vm, int flags)
446{
447	struct proc *p;
448
449	if (flags & ~(RUMP_RFFDG|RUMP_RFCFDG) ||
450	    (~flags & (RUMP_RFFDG|RUMP_RFCFDG)) == 0)
451		return EINVAL;
452
453	p = lwproc_newproc(curproc, vm, flags);
454	lwproc_makelwp(p, true, true);
455
456	return 0;
457}
458
459int
460rump_lwproc_rfork(int flags)
461{
462
463	return rump_lwproc_rfork_vmspace(rump_vmspace_local, flags);
464}
465
466/*
467 * Switch to a new process/thread.  Release previous one if
468 * deemed to be exiting.  This is considered a slow path for
469 * rump kernel entry.
470 */
471void
472rump_lwproc_switch(struct lwp *newlwp)
473{
474	struct lwp *l = curlwp;
475
476	KASSERT(!(l->l_flag & LW_WEXIT) || newlwp);
477
478	if (__predict_false(newlwp && (newlwp->l_pflag & LP_RUNNING)))
479		panic("lwp %p (%d:%d) already running",
480		    newlwp, newlwp->l_proc->p_pid, newlwp->l_lid);
481
482	if (newlwp == NULL) {
483		l->l_pflag &= ~LP_RUNNING;
484		l->l_flag |= LW_RUMP_CLEAR;
485		return;
486	}
487
488	/* fd_free() must be called from curlwp context.  talk about ugh */
489	if (l->l_flag & LW_WEXIT) {
490		fd_free();
491	}
492
493	KERNEL_UNLOCK_ALL(NULL, &l->l_biglocks);
494	lwproc_curlwpop(RUMPUSER_LWP_CLEAR, l);
495
496	newlwp->l_cpu = newlwp->l_target_cpu = l->l_cpu;
497	newlwp->l_mutex = l->l_mutex;
498	newlwp->l_pflag |= LP_RUNNING;
499
500	lwproc_curlwpop(RUMPUSER_LWP_SET, newlwp);
501	curcpu()->ci_curlwp = newlwp;
502	KERNEL_LOCK(newlwp->l_biglocks, NULL);
503
504	/*
505	 * Check if the thread should get a signal.  This is
506	 * mostly to satisfy the "record" rump sigmodel.
507	 */
508	mutex_enter(newlwp->l_proc->p_lock);
509	if (sigispending(newlwp, 0)) {
510		newlwp->l_flag |= LW_PENDSIG;
511	}
512	mutex_exit(newlwp->l_proc->p_lock);
513
514	l->l_mutex = &unruntime_lock;
515	l->l_pflag &= ~LP_RUNNING;
516	l->l_flag &= ~LW_PENDSIG;
517	l->l_stat = LSRUN;
518
519	if (l->l_flag & LW_WEXIT) {
520		l->l_stat = LSIDL;
521		lwproc_freelwp(l);
522	}
523}
524
525/*
526 * Mark the current thread to be released upon return from
527 * kernel.
528 */
529void
530rump_lwproc_releaselwp(void)
531{
532	struct lwp *l = curlwp;
533
534	if (l->l_refcnt == 0 || l->l_flag & LW_WEXIT)
535		panic("releasing non-pertinent lwp");
536
537	rump__lwproc_lwprele();
538	KASSERT(l->l_refcnt == 0 && (l->l_flag & LW_WEXIT));
539}
540
541/*
542 * In-kernel routines used to add and remove references for the
543 * current thread.  The main purpose is to make it possible for
544 * implicit threads to persist over scheduling operations in
545 * rump kernel drivers.  Note that we don't need p_lock in a
546 * rump kernel, since we do refcounting only for curlwp.
547 */
548void
549rump__lwproc_lwphold(void)
550{
551	struct lwp *l = curlwp;
552
553	l->l_refcnt++;
554	l->l_flag &= ~LW_WEXIT;
555}
556
557void
558rump__lwproc_lwprele(void)
559{
560	struct lwp *l = curlwp;
561
562	l->l_refcnt--;
563	if (l->l_refcnt == 0)
564		l->l_flag |= LW_WEXIT;
565}
566
567struct lwp *
568rump_lwproc_curlwp(void)
569{
570	struct lwp *l = curlwp;
571
572	if (l->l_flag & LW_WEXIT)
573		return NULL;
574	return l;
575}
576
577/* this interface is under construction (like the proverbial 90's web page) */
578int rump_i_know_what_i_am_doing_with_sysents = 0;
579void
580rump_lwproc_sysent_usenative()
581{
582
583	if (!rump_i_know_what_i_am_doing_with_sysents)
584		panic("don't use rump_lwproc_sysent_usenative()");
585	curproc->p_emul = &emul_netbsd;
586}
587