| 1 | /* $NetBSD: kern_sig.c,v 1.330 2016/09/13 07:39:45 martin Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc. |
| 5 | * All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to The NetBSD Foundation |
| 8 | * by Andrew Doran. |
| 9 | * |
| 10 | * Redistribution and use in source and binary forms, with or without |
| 11 | * modification, are permitted provided that the following conditions |
| 12 | * are met: |
| 13 | * 1. Redistributions of source code must retain the above copyright |
| 14 | * notice, this list of conditions and the following disclaimer. |
| 15 | * 2. Redistributions in binary form must reproduce the above copyright |
| 16 | * notice, this list of conditions and the following disclaimer in the |
| 17 | * documentation and/or other materials provided with the distribution. |
| 18 | * |
| 19 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
| 20 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| 21 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
| 23 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 24 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 25 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 26 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 27 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 28 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 29 | * POSSIBILITY OF SUCH DAMAGE. |
| 30 | */ |
| 31 | |
| 32 | /* |
| 33 | * Copyright (c) 1982, 1986, 1989, 1991, 1993 |
| 34 | * The Regents of the University of California. All rights reserved. |
| 35 | * (c) UNIX System Laboratories, Inc. |
| 36 | * All or some portions of this file are derived from material licensed |
| 37 | * to the University of California by American Telephone and Telegraph |
| 38 | * Co. or Unix System Laboratories, Inc. and are reproduced herein with |
| 39 | * the permission of UNIX System Laboratories, Inc. |
| 40 | * |
| 41 | * Redistribution and use in source and binary forms, with or without |
| 42 | * modification, are permitted provided that the following conditions |
| 43 | * are met: |
| 44 | * 1. Redistributions of source code must retain the above copyright |
| 45 | * notice, this list of conditions and the following disclaimer. |
| 46 | * 2. Redistributions in binary form must reproduce the above copyright |
| 47 | * notice, this list of conditions and the following disclaimer in the |
| 48 | * documentation and/or other materials provided with the distribution. |
| 49 | * 3. Neither the name of the University nor the names of its contributors |
| 50 | * may be used to endorse or promote products derived from this software |
| 51 | * without specific prior written permission. |
| 52 | * |
| 53 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 54 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 55 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 56 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 57 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 58 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 59 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 60 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 61 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 62 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 63 | * SUCH DAMAGE. |
| 64 | * |
| 65 | * @(#)kern_sig.c 8.14 (Berkeley) 5/14/95 |
| 66 | */ |
| 67 | |
| 68 | /* |
| 69 | * Signal subsystem. |
| 70 | */ |
| 71 | |
| 72 | #include <sys/cdefs.h> |
| 73 | __KERNEL_RCSID(0, "$NetBSD: kern_sig.c,v 1.330 2016/09/13 07:39:45 martin Exp $" ); |
| 74 | |
| 75 | #include "opt_ptrace.h" |
| 76 | #include "opt_dtrace.h" |
| 77 | #include "opt_compat_sunos.h" |
| 78 | #include "opt_compat_netbsd.h" |
| 79 | #include "opt_compat_netbsd32.h" |
| 80 | #include "opt_pax.h" |
| 81 | |
| 82 | #define SIGPROP /* include signal properties table */ |
| 83 | #include <sys/param.h> |
| 84 | #include <sys/signalvar.h> |
| 85 | #include <sys/proc.h> |
| 86 | #include <sys/systm.h> |
| 87 | #include <sys/wait.h> |
| 88 | #include <sys/ktrace.h> |
| 89 | #include <sys/syslog.h> |
| 90 | #include <sys/filedesc.h> |
| 91 | #include <sys/file.h> |
| 92 | #include <sys/pool.h> |
| 93 | #include <sys/ucontext.h> |
| 94 | #include <sys/exec.h> |
| 95 | #include <sys/kauth.h> |
| 96 | #include <sys/acct.h> |
| 97 | #include <sys/callout.h> |
| 98 | #include <sys/atomic.h> |
| 99 | #include <sys/cpu.h> |
| 100 | #include <sys/module.h> |
| 101 | #include <sys/sdt.h> |
| 102 | |
| 103 | #ifdef PAX_SEGVGUARD |
| 104 | #include <sys/pax.h> |
| 105 | #endif /* PAX_SEGVGUARD */ |
| 106 | |
| 107 | #include <uvm/uvm_extern.h> |
| 108 | |
| 109 | #define SIGQUEUE_MAX 32 |
| 110 | static pool_cache_t sigacts_cache __read_mostly; |
| 111 | static pool_cache_t ksiginfo_cache __read_mostly; |
| 112 | static callout_t proc_stop_ch __cacheline_aligned; |
| 113 | |
| 114 | sigset_t contsigmask __cacheline_aligned; |
| 115 | static sigset_t stopsigmask __cacheline_aligned; |
| 116 | sigset_t sigcantmask __cacheline_aligned; |
| 117 | |
| 118 | static void ksiginfo_exechook(struct proc *, void *); |
| 119 | static void proc_stop_callout(void *); |
| 120 | static int sigchecktrace(void); |
| 121 | static int sigpost(struct lwp *, sig_t, int, int); |
| 122 | static int sigput(sigpend_t *, struct proc *, ksiginfo_t *); |
| 123 | static int sigunwait(struct proc *, const ksiginfo_t *); |
| 124 | static void sigswitch(bool, int, int); |
| 125 | |
| 126 | static void sigacts_poolpage_free(struct pool *, void *); |
| 127 | static void *sigacts_poolpage_alloc(struct pool *, int); |
| 128 | |
| 129 | void (*sendsig_sigcontext_vec)(const struct ksiginfo *, const sigset_t *); |
| 130 | int (*coredump_vec)(struct lwp *, const char *) = |
| 131 | (int (*)(struct lwp *, const char *))enosys; |
| 132 | |
| 133 | /* |
| 134 | * DTrace SDT provider definitions |
| 135 | */ |
| 136 | SDT_PROVIDER_DECLARE(proc); |
| 137 | SDT_PROBE_DEFINE3(proc, kernel, , signal__send, |
| 138 | "struct lwp *" , /* target thread */ |
| 139 | "struct proc *" , /* target process */ |
| 140 | "int" ); /* signal */ |
| 141 | SDT_PROBE_DEFINE3(proc, kernel, , signal__discard, |
| 142 | "struct lwp *" , /* target thread */ |
| 143 | "struct proc *" , /* target process */ |
| 144 | "int" ); /* signal */ |
| 145 | SDT_PROBE_DEFINE3(proc, kernel, , signal__handle, |
| 146 | "int" , /* signal */ |
| 147 | "ksiginfo_t *" , /* signal info */ |
| 148 | "void (*)(void)" ); /* handler address */ |
| 149 | |
| 150 | |
| 151 | static struct pool_allocator sigactspool_allocator = { |
| 152 | .pa_alloc = sigacts_poolpage_alloc, |
| 153 | .pa_free = sigacts_poolpage_free |
| 154 | }; |
| 155 | |
| 156 | #ifdef DEBUG |
| 157 | int kern_logsigexit = 1; |
| 158 | #else |
| 159 | int kern_logsigexit = 0; |
| 160 | #endif |
| 161 | |
| 162 | static const char logcoredump[] = |
| 163 | "pid %d (%s), uid %d: exited on signal %d (core dumped)\n" ; |
| 164 | static const char lognocoredump[] = |
| 165 | "pid %d (%s), uid %d: exited on signal %d (core not dumped, err = %d)\n" ; |
| 166 | |
| 167 | static kauth_listener_t signal_listener; |
| 168 | |
| 169 | static int |
| 170 | signal_listener_cb(kauth_cred_t cred, kauth_action_t action, void *cookie, |
| 171 | void *arg0, void *arg1, void *arg2, void *arg3) |
| 172 | { |
| 173 | struct proc *p; |
| 174 | int result, signum; |
| 175 | |
| 176 | result = KAUTH_RESULT_DEFER; |
| 177 | p = arg0; |
| 178 | signum = (int)(unsigned long)arg1; |
| 179 | |
| 180 | if (action != KAUTH_PROCESS_SIGNAL) |
| 181 | return result; |
| 182 | |
| 183 | if (kauth_cred_uidmatch(cred, p->p_cred) || |
| 184 | (signum == SIGCONT && (curproc->p_session == p->p_session))) |
| 185 | result = KAUTH_RESULT_ALLOW; |
| 186 | |
| 187 | return result; |
| 188 | } |
| 189 | |
| 190 | /* |
| 191 | * signal_init: |
| 192 | * |
| 193 | * Initialize global signal-related data structures. |
| 194 | */ |
| 195 | void |
| 196 | signal_init(void) |
| 197 | { |
| 198 | |
| 199 | sigactspool_allocator.pa_pagesz = (PAGE_SIZE)*2; |
| 200 | |
| 201 | sigacts_cache = pool_cache_init(sizeof(struct sigacts), 0, 0, 0, |
| 202 | "sigacts" , sizeof(struct sigacts) > PAGE_SIZE ? |
| 203 | &sigactspool_allocator : NULL, IPL_NONE, NULL, NULL, NULL); |
| 204 | ksiginfo_cache = pool_cache_init(sizeof(ksiginfo_t), 0, 0, 0, |
| 205 | "ksiginfo" , NULL, IPL_VM, NULL, NULL, NULL); |
| 206 | |
| 207 | exechook_establish(ksiginfo_exechook, NULL); |
| 208 | |
| 209 | callout_init(&proc_stop_ch, CALLOUT_MPSAFE); |
| 210 | callout_setfunc(&proc_stop_ch, proc_stop_callout, NULL); |
| 211 | |
| 212 | signal_listener = kauth_listen_scope(KAUTH_SCOPE_PROCESS, |
| 213 | signal_listener_cb, NULL); |
| 214 | } |
| 215 | |
| 216 | /* |
| 217 | * sigacts_poolpage_alloc: |
| 218 | * |
| 219 | * Allocate a page for the sigacts memory pool. |
| 220 | */ |
| 221 | static void * |
| 222 | sigacts_poolpage_alloc(struct pool *pp, int flags) |
| 223 | { |
| 224 | |
| 225 | return (void *)uvm_km_alloc(kernel_map, |
| 226 | PAGE_SIZE * 2, PAGE_SIZE * 2, |
| 227 | ((flags & PR_WAITOK) ? 0 : UVM_KMF_NOWAIT | UVM_KMF_TRYLOCK) |
| 228 | | UVM_KMF_WIRED); |
| 229 | } |
| 230 | |
| 231 | /* |
| 232 | * sigacts_poolpage_free: |
| 233 | * |
| 234 | * Free a page on behalf of the sigacts memory pool. |
| 235 | */ |
| 236 | static void |
| 237 | sigacts_poolpage_free(struct pool *pp, void *v) |
| 238 | { |
| 239 | |
| 240 | uvm_km_free(kernel_map, (vaddr_t)v, PAGE_SIZE * 2, UVM_KMF_WIRED); |
| 241 | } |
| 242 | |
| 243 | /* |
| 244 | * sigactsinit: |
| 245 | * |
| 246 | * Create an initial sigacts structure, using the same signal state |
| 247 | * as of specified process. If 'share' is set, share the sigacts by |
| 248 | * holding a reference, otherwise just copy it from parent. |
| 249 | */ |
| 250 | struct sigacts * |
| 251 | sigactsinit(struct proc *pp, int share) |
| 252 | { |
| 253 | struct sigacts *ps = pp->p_sigacts, *ps2; |
| 254 | |
| 255 | if (__predict_false(share)) { |
| 256 | atomic_inc_uint(&ps->sa_refcnt); |
| 257 | return ps; |
| 258 | } |
| 259 | ps2 = pool_cache_get(sigacts_cache, PR_WAITOK); |
| 260 | mutex_init(&ps2->sa_mutex, MUTEX_DEFAULT, IPL_SCHED); |
| 261 | ps2->sa_refcnt = 1; |
| 262 | |
| 263 | mutex_enter(&ps->sa_mutex); |
| 264 | memcpy(ps2->sa_sigdesc, ps->sa_sigdesc, sizeof(ps2->sa_sigdesc)); |
| 265 | mutex_exit(&ps->sa_mutex); |
| 266 | return ps2; |
| 267 | } |
| 268 | |
| 269 | /* |
| 270 | * sigactsunshare: |
| 271 | * |
| 272 | * Make this process not share its sigacts, maintaining all signal state. |
| 273 | */ |
| 274 | void |
| 275 | sigactsunshare(struct proc *p) |
| 276 | { |
| 277 | struct sigacts *ps, *oldps = p->p_sigacts; |
| 278 | |
| 279 | if (__predict_true(oldps->sa_refcnt == 1)) |
| 280 | return; |
| 281 | |
| 282 | ps = pool_cache_get(sigacts_cache, PR_WAITOK); |
| 283 | mutex_init(&ps->sa_mutex, MUTEX_DEFAULT, IPL_SCHED); |
| 284 | memcpy(ps->sa_sigdesc, oldps->sa_sigdesc, sizeof(ps->sa_sigdesc)); |
| 285 | ps->sa_refcnt = 1; |
| 286 | |
| 287 | p->p_sigacts = ps; |
| 288 | sigactsfree(oldps); |
| 289 | } |
| 290 | |
| 291 | /* |
| 292 | * sigactsfree; |
| 293 | * |
| 294 | * Release a sigacts structure. |
| 295 | */ |
| 296 | void |
| 297 | sigactsfree(struct sigacts *ps) |
| 298 | { |
| 299 | |
| 300 | if (atomic_dec_uint_nv(&ps->sa_refcnt) == 0) { |
| 301 | mutex_destroy(&ps->sa_mutex); |
| 302 | pool_cache_put(sigacts_cache, ps); |
| 303 | } |
| 304 | } |
| 305 | |
| 306 | /* |
| 307 | * siginit: |
| 308 | * |
| 309 | * Initialize signal state for process 0; set to ignore signals that |
| 310 | * are ignored by default and disable the signal stack. Locking not |
| 311 | * required as the system is still cold. |
| 312 | */ |
| 313 | void |
| 314 | siginit(struct proc *p) |
| 315 | { |
| 316 | struct lwp *l; |
| 317 | struct sigacts *ps; |
| 318 | int signo, prop; |
| 319 | |
| 320 | ps = p->p_sigacts; |
| 321 | sigemptyset(&contsigmask); |
| 322 | sigemptyset(&stopsigmask); |
| 323 | sigemptyset(&sigcantmask); |
| 324 | for (signo = 1; signo < NSIG; signo++) { |
| 325 | prop = sigprop[signo]; |
| 326 | if (prop & SA_CONT) |
| 327 | sigaddset(&contsigmask, signo); |
| 328 | if (prop & SA_STOP) |
| 329 | sigaddset(&stopsigmask, signo); |
| 330 | if (prop & SA_CANTMASK) |
| 331 | sigaddset(&sigcantmask, signo); |
| 332 | if (prop & SA_IGNORE && signo != SIGCONT) |
| 333 | sigaddset(&p->p_sigctx.ps_sigignore, signo); |
| 334 | sigemptyset(&SIGACTION_PS(ps, signo).sa_mask); |
| 335 | SIGACTION_PS(ps, signo).sa_flags = SA_RESTART; |
| 336 | } |
| 337 | sigemptyset(&p->p_sigctx.ps_sigcatch); |
| 338 | p->p_sflag &= ~PS_NOCLDSTOP; |
| 339 | |
| 340 | ksiginfo_queue_init(&p->p_sigpend.sp_info); |
| 341 | sigemptyset(&p->p_sigpend.sp_set); |
| 342 | |
| 343 | /* |
| 344 | * Reset per LWP state. |
| 345 | */ |
| 346 | l = LIST_FIRST(&p->p_lwps); |
| 347 | l->l_sigwaited = NULL; |
| 348 | l->l_sigstk.ss_flags = SS_DISABLE; |
| 349 | l->l_sigstk.ss_size = 0; |
| 350 | l->l_sigstk.ss_sp = 0; |
| 351 | ksiginfo_queue_init(&l->l_sigpend.sp_info); |
| 352 | sigemptyset(&l->l_sigpend.sp_set); |
| 353 | |
| 354 | /* One reference. */ |
| 355 | ps->sa_refcnt = 1; |
| 356 | } |
| 357 | |
| 358 | /* |
| 359 | * execsigs: |
| 360 | * |
| 361 | * Reset signals for an exec of the specified process. |
| 362 | */ |
| 363 | void |
| 364 | execsigs(struct proc *p) |
| 365 | { |
| 366 | struct sigacts *ps; |
| 367 | struct lwp *l; |
| 368 | int signo, prop; |
| 369 | sigset_t tset; |
| 370 | ksiginfoq_t kq; |
| 371 | |
| 372 | KASSERT(p->p_nlwps == 1); |
| 373 | |
| 374 | sigactsunshare(p); |
| 375 | ps = p->p_sigacts; |
| 376 | |
| 377 | /* |
| 378 | * Reset caught signals. Held signals remain held through |
| 379 | * l->l_sigmask (unless they were caught, and are now ignored |
| 380 | * by default). |
| 381 | * |
| 382 | * No need to lock yet, the process has only one LWP and |
| 383 | * at this point the sigacts are private to the process. |
| 384 | */ |
| 385 | sigemptyset(&tset); |
| 386 | for (signo = 1; signo < NSIG; signo++) { |
| 387 | if (sigismember(&p->p_sigctx.ps_sigcatch, signo)) { |
| 388 | prop = sigprop[signo]; |
| 389 | if (prop & SA_IGNORE) { |
| 390 | if ((prop & SA_CONT) == 0) |
| 391 | sigaddset(&p->p_sigctx.ps_sigignore, |
| 392 | signo); |
| 393 | sigaddset(&tset, signo); |
| 394 | } |
| 395 | SIGACTION_PS(ps, signo).sa_handler = SIG_DFL; |
| 396 | } |
| 397 | sigemptyset(&SIGACTION_PS(ps, signo).sa_mask); |
| 398 | SIGACTION_PS(ps, signo).sa_flags = SA_RESTART; |
| 399 | } |
| 400 | ksiginfo_queue_init(&kq); |
| 401 | |
| 402 | mutex_enter(p->p_lock); |
| 403 | sigclearall(p, &tset, &kq); |
| 404 | sigemptyset(&p->p_sigctx.ps_sigcatch); |
| 405 | |
| 406 | /* |
| 407 | * Reset no zombies if child dies flag as Solaris does. |
| 408 | */ |
| 409 | p->p_flag &= ~(PK_NOCLDWAIT | PK_CLDSIGIGN); |
| 410 | if (SIGACTION_PS(ps, SIGCHLD).sa_handler == SIG_IGN) |
| 411 | SIGACTION_PS(ps, SIGCHLD).sa_handler = SIG_DFL; |
| 412 | |
| 413 | /* |
| 414 | * Reset per-LWP state. |
| 415 | */ |
| 416 | l = LIST_FIRST(&p->p_lwps); |
| 417 | l->l_sigwaited = NULL; |
| 418 | l->l_sigstk.ss_flags = SS_DISABLE; |
| 419 | l->l_sigstk.ss_size = 0; |
| 420 | l->l_sigstk.ss_sp = 0; |
| 421 | ksiginfo_queue_init(&l->l_sigpend.sp_info); |
| 422 | sigemptyset(&l->l_sigpend.sp_set); |
| 423 | mutex_exit(p->p_lock); |
| 424 | |
| 425 | ksiginfo_queue_drain(&kq); |
| 426 | } |
| 427 | |
| 428 | /* |
| 429 | * ksiginfo_exechook: |
| 430 | * |
| 431 | * Free all pending ksiginfo entries from a process on exec. |
| 432 | * Additionally, drain any unused ksiginfo structures in the |
| 433 | * system back to the pool. |
| 434 | * |
| 435 | * XXX This should not be a hook, every process has signals. |
| 436 | */ |
| 437 | static void |
| 438 | ksiginfo_exechook(struct proc *p, void *v) |
| 439 | { |
| 440 | ksiginfoq_t kq; |
| 441 | |
| 442 | ksiginfo_queue_init(&kq); |
| 443 | |
| 444 | mutex_enter(p->p_lock); |
| 445 | sigclearall(p, NULL, &kq); |
| 446 | mutex_exit(p->p_lock); |
| 447 | |
| 448 | ksiginfo_queue_drain(&kq); |
| 449 | } |
| 450 | |
| 451 | /* |
| 452 | * ksiginfo_alloc: |
| 453 | * |
| 454 | * Allocate a new ksiginfo structure from the pool, and optionally copy |
| 455 | * an existing one. If the existing ksiginfo_t is from the pool, and |
| 456 | * has not been queued somewhere, then just return it. Additionally, |
| 457 | * if the existing ksiginfo_t does not contain any information beyond |
| 458 | * the signal number, then just return it. |
| 459 | */ |
| 460 | ksiginfo_t * |
| 461 | ksiginfo_alloc(struct proc *p, ksiginfo_t *ok, int flags) |
| 462 | { |
| 463 | ksiginfo_t *kp; |
| 464 | |
| 465 | if (ok != NULL) { |
| 466 | if ((ok->ksi_flags & (KSI_QUEUED | KSI_FROMPOOL)) == |
| 467 | KSI_FROMPOOL) |
| 468 | return ok; |
| 469 | if (KSI_EMPTY_P(ok)) |
| 470 | return ok; |
| 471 | } |
| 472 | |
| 473 | kp = pool_cache_get(ksiginfo_cache, flags); |
| 474 | if (kp == NULL) { |
| 475 | #ifdef DIAGNOSTIC |
| 476 | printf("Out of memory allocating ksiginfo for pid %d\n" , |
| 477 | p->p_pid); |
| 478 | #endif |
| 479 | return NULL; |
| 480 | } |
| 481 | |
| 482 | if (ok != NULL) { |
| 483 | memcpy(kp, ok, sizeof(*kp)); |
| 484 | kp->ksi_flags &= ~KSI_QUEUED; |
| 485 | } else |
| 486 | KSI_INIT_EMPTY(kp); |
| 487 | |
| 488 | kp->ksi_flags |= KSI_FROMPOOL; |
| 489 | |
| 490 | return kp; |
| 491 | } |
| 492 | |
| 493 | /* |
| 494 | * ksiginfo_free: |
| 495 | * |
| 496 | * If the given ksiginfo_t is from the pool and has not been queued, |
| 497 | * then free it. |
| 498 | */ |
| 499 | void |
| 500 | ksiginfo_free(ksiginfo_t *kp) |
| 501 | { |
| 502 | |
| 503 | if ((kp->ksi_flags & (KSI_QUEUED | KSI_FROMPOOL)) != KSI_FROMPOOL) |
| 504 | return; |
| 505 | pool_cache_put(ksiginfo_cache, kp); |
| 506 | } |
| 507 | |
| 508 | /* |
| 509 | * ksiginfo_queue_drain: |
| 510 | * |
| 511 | * Drain a non-empty ksiginfo_t queue. |
| 512 | */ |
| 513 | void |
| 514 | ksiginfo_queue_drain0(ksiginfoq_t *kq) |
| 515 | { |
| 516 | ksiginfo_t *ksi; |
| 517 | |
| 518 | KASSERT(!TAILQ_EMPTY(kq)); |
| 519 | |
| 520 | while (!TAILQ_EMPTY(kq)) { |
| 521 | ksi = TAILQ_FIRST(kq); |
| 522 | TAILQ_REMOVE(kq, ksi, ksi_list); |
| 523 | pool_cache_put(ksiginfo_cache, ksi); |
| 524 | } |
| 525 | } |
| 526 | |
| 527 | static int |
| 528 | siggetinfo(sigpend_t *sp, ksiginfo_t *out, int signo) |
| 529 | { |
| 530 | ksiginfo_t *ksi, *nksi; |
| 531 | |
| 532 | if (sp == NULL) |
| 533 | goto out; |
| 534 | |
| 535 | /* Find siginfo and copy it out. */ |
| 536 | int count = 0; |
| 537 | TAILQ_FOREACH_SAFE(ksi, &sp->sp_info, ksi_list, nksi) { |
| 538 | if (ksi->ksi_signo != signo) |
| 539 | continue; |
| 540 | if (count++ > 0) /* Only remove the first, count all of them */ |
| 541 | continue; |
| 542 | TAILQ_REMOVE(&sp->sp_info, ksi, ksi_list); |
| 543 | KASSERT((ksi->ksi_flags & KSI_FROMPOOL) != 0); |
| 544 | KASSERT((ksi->ksi_flags & KSI_QUEUED) != 0); |
| 545 | ksi->ksi_flags &= ~KSI_QUEUED; |
| 546 | if (out != NULL) { |
| 547 | memcpy(out, ksi, sizeof(*out)); |
| 548 | out->ksi_flags &= ~(KSI_FROMPOOL | KSI_QUEUED); |
| 549 | } |
| 550 | ksiginfo_free(ksi); |
| 551 | } |
| 552 | if (count) |
| 553 | return count; |
| 554 | |
| 555 | out: |
| 556 | /* If there is no siginfo, then manufacture it. */ |
| 557 | if (out != NULL) { |
| 558 | KSI_INIT(out); |
| 559 | out->ksi_info._signo = signo; |
| 560 | out->ksi_info._code = SI_NOINFO; |
| 561 | } |
| 562 | return 0; |
| 563 | } |
| 564 | |
| 565 | /* |
| 566 | * sigget: |
| 567 | * |
| 568 | * Fetch the first pending signal from a set. Optionally, also fetch |
| 569 | * or manufacture a ksiginfo element. Returns the number of the first |
| 570 | * pending signal, or zero. |
| 571 | */ |
| 572 | int |
| 573 | sigget(sigpend_t *sp, ksiginfo_t *out, int signo, const sigset_t *mask) |
| 574 | { |
| 575 | sigset_t tset; |
| 576 | int count; |
| 577 | |
| 578 | /* If there's no pending set, the signal is from the debugger. */ |
| 579 | if (sp == NULL) |
| 580 | goto out; |
| 581 | |
| 582 | /* Construct mask from signo, and 'mask'. */ |
| 583 | if (signo == 0) { |
| 584 | if (mask != NULL) { |
| 585 | tset = *mask; |
| 586 | __sigandset(&sp->sp_set, &tset); |
| 587 | } else |
| 588 | tset = sp->sp_set; |
| 589 | |
| 590 | /* If there are no signals pending - return. */ |
| 591 | if ((signo = firstsig(&tset)) == 0) |
| 592 | goto out; |
| 593 | } else { |
| 594 | KASSERT(sigismember(&sp->sp_set, signo)); |
| 595 | } |
| 596 | |
| 597 | sigdelset(&sp->sp_set, signo); |
| 598 | out: |
| 599 | count = siggetinfo(sp, out, signo); |
| 600 | if (count > 1) |
| 601 | sigaddset(&sp->sp_set, signo); |
| 602 | return signo; |
| 603 | } |
| 604 | |
| 605 | /* |
| 606 | * sigput: |
| 607 | * |
| 608 | * Append a new ksiginfo element to the list of pending ksiginfo's. |
| 609 | */ |
| 610 | static int |
| 611 | sigput(sigpend_t *sp, struct proc *p, ksiginfo_t *ksi) |
| 612 | { |
| 613 | ksiginfo_t *kp; |
| 614 | |
| 615 | KASSERT(mutex_owned(p->p_lock)); |
| 616 | KASSERT((ksi->ksi_flags & KSI_QUEUED) == 0); |
| 617 | |
| 618 | sigaddset(&sp->sp_set, ksi->ksi_signo); |
| 619 | |
| 620 | /* |
| 621 | * If there is no siginfo, we are done. |
| 622 | */ |
| 623 | if (KSI_EMPTY_P(ksi)) |
| 624 | return 0; |
| 625 | |
| 626 | KASSERT((ksi->ksi_flags & KSI_FROMPOOL) != 0); |
| 627 | |
| 628 | size_t count = 0; |
| 629 | TAILQ_FOREACH(kp, &sp->sp_info, ksi_list) { |
| 630 | count++; |
| 631 | if (ksi->ksi_signo >= SIGRTMIN && ksi->ksi_signo <= SIGRTMAX) |
| 632 | continue; |
| 633 | if (kp->ksi_signo == ksi->ksi_signo) { |
| 634 | KSI_COPY(ksi, kp); |
| 635 | kp->ksi_flags |= KSI_QUEUED; |
| 636 | return 0; |
| 637 | } |
| 638 | } |
| 639 | |
| 640 | if (count >= SIGQUEUE_MAX) { |
| 641 | #ifdef DIAGNOSTIC |
| 642 | printf("%s(%d): Signal queue is full signal=%d\n" , |
| 643 | p->p_comm, p->p_pid, ksi->ksi_signo); |
| 644 | #endif |
| 645 | return EAGAIN; |
| 646 | } |
| 647 | ksi->ksi_flags |= KSI_QUEUED; |
| 648 | TAILQ_INSERT_TAIL(&sp->sp_info, ksi, ksi_list); |
| 649 | |
| 650 | return 0; |
| 651 | } |
| 652 | |
| 653 | /* |
| 654 | * sigclear: |
| 655 | * |
| 656 | * Clear all pending signals in the specified set. |
| 657 | */ |
| 658 | void |
| 659 | sigclear(sigpend_t *sp, const sigset_t *mask, ksiginfoq_t *kq) |
| 660 | { |
| 661 | ksiginfo_t *ksi, *next; |
| 662 | |
| 663 | if (mask == NULL) |
| 664 | sigemptyset(&sp->sp_set); |
| 665 | else |
| 666 | sigminusset(mask, &sp->sp_set); |
| 667 | |
| 668 | TAILQ_FOREACH_SAFE(ksi, &sp->sp_info, ksi_list, next) { |
| 669 | if (mask == NULL || sigismember(mask, ksi->ksi_signo)) { |
| 670 | TAILQ_REMOVE(&sp->sp_info, ksi, ksi_list); |
| 671 | KASSERT((ksi->ksi_flags & KSI_FROMPOOL) != 0); |
| 672 | KASSERT((ksi->ksi_flags & KSI_QUEUED) != 0); |
| 673 | TAILQ_INSERT_TAIL(kq, ksi, ksi_list); |
| 674 | } |
| 675 | } |
| 676 | } |
| 677 | |
| 678 | /* |
| 679 | * sigclearall: |
| 680 | * |
| 681 | * Clear all pending signals in the specified set from a process and |
| 682 | * its LWPs. |
| 683 | */ |
| 684 | void |
| 685 | sigclearall(struct proc *p, const sigset_t *mask, ksiginfoq_t *kq) |
| 686 | { |
| 687 | struct lwp *l; |
| 688 | |
| 689 | KASSERT(mutex_owned(p->p_lock)); |
| 690 | |
| 691 | sigclear(&p->p_sigpend, mask, kq); |
| 692 | |
| 693 | LIST_FOREACH(l, &p->p_lwps, l_sibling) { |
| 694 | sigclear(&l->l_sigpend, mask, kq); |
| 695 | } |
| 696 | } |
| 697 | |
| 698 | /* |
| 699 | * sigispending: |
| 700 | * |
| 701 | * Return the first signal number if there are pending signals for the |
| 702 | * current LWP. May be called unlocked provided that LW_PENDSIG is set, |
| 703 | * and that the signal has been posted to the appopriate queue before |
| 704 | * LW_PENDSIG is set. |
| 705 | */ |
| 706 | int |
| 707 | sigispending(struct lwp *l, int signo) |
| 708 | { |
| 709 | struct proc *p = l->l_proc; |
| 710 | sigset_t tset; |
| 711 | |
| 712 | membar_consumer(); |
| 713 | |
| 714 | tset = l->l_sigpend.sp_set; |
| 715 | sigplusset(&p->p_sigpend.sp_set, &tset); |
| 716 | sigminusset(&p->p_sigctx.ps_sigignore, &tset); |
| 717 | sigminusset(&l->l_sigmask, &tset); |
| 718 | |
| 719 | if (signo == 0) { |
| 720 | return firstsig(&tset); |
| 721 | } |
| 722 | return sigismember(&tset, signo) ? signo : 0; |
| 723 | } |
| 724 | |
| 725 | void |
| 726 | getucontext(struct lwp *l, ucontext_t *ucp) |
| 727 | { |
| 728 | struct proc *p = l->l_proc; |
| 729 | |
| 730 | KASSERT(mutex_owned(p->p_lock)); |
| 731 | |
| 732 | ucp->uc_flags = 0; |
| 733 | ucp->uc_link = l->l_ctxlink; |
| 734 | ucp->uc_sigmask = l->l_sigmask; |
| 735 | ucp->uc_flags |= _UC_SIGMASK; |
| 736 | |
| 737 | /* |
| 738 | * The (unsupplied) definition of the `current execution stack' |
| 739 | * in the System V Interface Definition appears to allow returning |
| 740 | * the main context stack. |
| 741 | */ |
| 742 | if ((l->l_sigstk.ss_flags & SS_ONSTACK) == 0) { |
| 743 | ucp->uc_stack.ss_sp = (void *)l->l_proc->p_stackbase; |
| 744 | ucp->uc_stack.ss_size = ctob(l->l_proc->p_vmspace->vm_ssize); |
| 745 | ucp->uc_stack.ss_flags = 0; /* XXX, def. is Very Fishy */ |
| 746 | } else { |
| 747 | /* Simply copy alternate signal execution stack. */ |
| 748 | ucp->uc_stack = l->l_sigstk; |
| 749 | } |
| 750 | ucp->uc_flags |= _UC_STACK; |
| 751 | mutex_exit(p->p_lock); |
| 752 | cpu_getmcontext(l, &ucp->uc_mcontext, &ucp->uc_flags); |
| 753 | mutex_enter(p->p_lock); |
| 754 | } |
| 755 | |
| 756 | int |
| 757 | setucontext(struct lwp *l, const ucontext_t *ucp) |
| 758 | { |
| 759 | struct proc *p = l->l_proc; |
| 760 | int error; |
| 761 | |
| 762 | KASSERT(mutex_owned(p->p_lock)); |
| 763 | |
| 764 | if ((ucp->uc_flags & _UC_SIGMASK) != 0) { |
| 765 | error = sigprocmask1(l, SIG_SETMASK, &ucp->uc_sigmask, NULL); |
| 766 | if (error != 0) |
| 767 | return error; |
| 768 | } |
| 769 | |
| 770 | mutex_exit(p->p_lock); |
| 771 | error = cpu_setmcontext(l, &ucp->uc_mcontext, ucp->uc_flags); |
| 772 | mutex_enter(p->p_lock); |
| 773 | if (error != 0) |
| 774 | return (error); |
| 775 | |
| 776 | l->l_ctxlink = ucp->uc_link; |
| 777 | |
| 778 | /* |
| 779 | * If there was stack information, update whether or not we are |
| 780 | * still running on an alternate signal stack. |
| 781 | */ |
| 782 | if ((ucp->uc_flags & _UC_STACK) != 0) { |
| 783 | if (ucp->uc_stack.ss_flags & SS_ONSTACK) |
| 784 | l->l_sigstk.ss_flags |= SS_ONSTACK; |
| 785 | else |
| 786 | l->l_sigstk.ss_flags &= ~SS_ONSTACK; |
| 787 | } |
| 788 | |
| 789 | return 0; |
| 790 | } |
| 791 | |
| 792 | /* |
| 793 | * killpg1: common code for kill process group/broadcast kill. |
| 794 | */ |
| 795 | int |
| 796 | killpg1(struct lwp *l, ksiginfo_t *ksi, int pgid, int all) |
| 797 | { |
| 798 | struct proc *p, *cp; |
| 799 | kauth_cred_t pc; |
| 800 | struct pgrp *pgrp; |
| 801 | int nfound; |
| 802 | int signo = ksi->ksi_signo; |
| 803 | |
| 804 | cp = l->l_proc; |
| 805 | pc = l->l_cred; |
| 806 | nfound = 0; |
| 807 | |
| 808 | mutex_enter(proc_lock); |
| 809 | if (all) { |
| 810 | /* |
| 811 | * Broadcast. |
| 812 | */ |
| 813 | PROCLIST_FOREACH(p, &allproc) { |
| 814 | if (p->p_pid <= 1 || p == cp || |
| 815 | (p->p_flag & PK_SYSTEM) != 0) |
| 816 | continue; |
| 817 | mutex_enter(p->p_lock); |
| 818 | if (kauth_authorize_process(pc, |
| 819 | KAUTH_PROCESS_SIGNAL, p, KAUTH_ARG(signo), NULL, |
| 820 | NULL) == 0) { |
| 821 | nfound++; |
| 822 | if (signo) |
| 823 | kpsignal2(p, ksi); |
| 824 | } |
| 825 | mutex_exit(p->p_lock); |
| 826 | } |
| 827 | } else { |
| 828 | if (pgid == 0) |
| 829 | /* Zero pgid means send to my process group. */ |
| 830 | pgrp = cp->p_pgrp; |
| 831 | else { |
| 832 | pgrp = pgrp_find(pgid); |
| 833 | if (pgrp == NULL) |
| 834 | goto out; |
| 835 | } |
| 836 | LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { |
| 837 | if (p->p_pid <= 1 || p->p_flag & PK_SYSTEM) |
| 838 | continue; |
| 839 | mutex_enter(p->p_lock); |
| 840 | if (kauth_authorize_process(pc, KAUTH_PROCESS_SIGNAL, |
| 841 | p, KAUTH_ARG(signo), NULL, NULL) == 0) { |
| 842 | nfound++; |
| 843 | if (signo && P_ZOMBIE(p) == 0) |
| 844 | kpsignal2(p, ksi); |
| 845 | } |
| 846 | mutex_exit(p->p_lock); |
| 847 | } |
| 848 | } |
| 849 | out: |
| 850 | mutex_exit(proc_lock); |
| 851 | return nfound ? 0 : ESRCH; |
| 852 | } |
| 853 | |
| 854 | /* |
| 855 | * Send a signal to a process group. If checktty is set, limit to members |
| 856 | * which have a controlling terminal. |
| 857 | */ |
| 858 | void |
| 859 | pgsignal(struct pgrp *pgrp, int sig, int checkctty) |
| 860 | { |
| 861 | ksiginfo_t ksi; |
| 862 | |
| 863 | KASSERT(!cpu_intr_p()); |
| 864 | KASSERT(mutex_owned(proc_lock)); |
| 865 | |
| 866 | KSI_INIT_EMPTY(&ksi); |
| 867 | ksi.ksi_signo = sig; |
| 868 | kpgsignal(pgrp, &ksi, NULL, checkctty); |
| 869 | } |
| 870 | |
| 871 | void |
| 872 | kpgsignal(struct pgrp *pgrp, ksiginfo_t *ksi, void *data, int checkctty) |
| 873 | { |
| 874 | struct proc *p; |
| 875 | |
| 876 | KASSERT(!cpu_intr_p()); |
| 877 | KASSERT(mutex_owned(proc_lock)); |
| 878 | KASSERT(pgrp != NULL); |
| 879 | |
| 880 | LIST_FOREACH(p, &pgrp->pg_members, p_pglist) |
| 881 | if (checkctty == 0 || p->p_lflag & PL_CONTROLT) |
| 882 | kpsignal(p, ksi, data); |
| 883 | } |
| 884 | |
| 885 | /* |
| 886 | * Send a signal caused by a trap to the current LWP. If it will be caught |
| 887 | * immediately, deliver it with correct code. Otherwise, post it normally. |
| 888 | */ |
| 889 | void |
| 890 | trapsignal(struct lwp *l, ksiginfo_t *ksi) |
| 891 | { |
| 892 | struct proc *p; |
| 893 | struct sigacts *ps; |
| 894 | int signo = ksi->ksi_signo; |
| 895 | sigset_t *mask; |
| 896 | |
| 897 | KASSERT(KSI_TRAP_P(ksi)); |
| 898 | |
| 899 | ksi->ksi_lid = l->l_lid; |
| 900 | p = l->l_proc; |
| 901 | |
| 902 | KASSERT(!cpu_intr_p()); |
| 903 | mutex_enter(proc_lock); |
| 904 | mutex_enter(p->p_lock); |
| 905 | mask = &l->l_sigmask; |
| 906 | ps = p->p_sigacts; |
| 907 | |
| 908 | if ((p->p_slflag & PSL_TRACED) == 0 && |
| 909 | sigismember(&p->p_sigctx.ps_sigcatch, signo) && |
| 910 | !sigismember(mask, signo)) { |
| 911 | mutex_exit(proc_lock); |
| 912 | l->l_ru.ru_nsignals++; |
| 913 | kpsendsig(l, ksi, mask); |
| 914 | mutex_exit(p->p_lock); |
| 915 | if (ktrpoint(KTR_PSIG)) { |
| 916 | if (p->p_emul->e_ktrpsig) |
| 917 | p->p_emul->e_ktrpsig(signo, |
| 918 | SIGACTION_PS(ps, signo).sa_handler, |
| 919 | mask, ksi); |
| 920 | else |
| 921 | ktrpsig(signo, |
| 922 | SIGACTION_PS(ps, signo).sa_handler, |
| 923 | mask, ksi); |
| 924 | } |
| 925 | } else { |
| 926 | /* XXX for core dump/debugger */ |
| 927 | p->p_sigctx.ps_lwp = l->l_lid; |
| 928 | p->p_sigctx.ps_signo = ksi->ksi_signo; |
| 929 | p->p_sigctx.ps_code = ksi->ksi_trap; |
| 930 | kpsignal2(p, ksi); |
| 931 | mutex_exit(p->p_lock); |
| 932 | mutex_exit(proc_lock); |
| 933 | } |
| 934 | } |
| 935 | |
| 936 | /* |
| 937 | * Fill in signal information and signal the parent for a child status change. |
| 938 | */ |
| 939 | void |
| 940 | child_psignal(struct proc *p, int mask) |
| 941 | { |
| 942 | ksiginfo_t ksi; |
| 943 | struct proc *q; |
| 944 | int xsig; |
| 945 | |
| 946 | KASSERT(mutex_owned(proc_lock)); |
| 947 | KASSERT(mutex_owned(p->p_lock)); |
| 948 | |
| 949 | xsig = p->p_xsig; |
| 950 | |
| 951 | KSI_INIT(&ksi); |
| 952 | ksi.ksi_signo = SIGCHLD; |
| 953 | ksi.ksi_code = (xsig == SIGCONT ? CLD_CONTINUED : CLD_STOPPED); |
| 954 | ksi.ksi_pid = p->p_pid; |
| 955 | ksi.ksi_uid = kauth_cred_geteuid(p->p_cred); |
| 956 | ksi.ksi_status = xsig; |
| 957 | ksi.ksi_utime = p->p_stats->p_ru.ru_utime.tv_sec; |
| 958 | ksi.ksi_stime = p->p_stats->p_ru.ru_stime.tv_sec; |
| 959 | |
| 960 | q = p->p_pptr; |
| 961 | |
| 962 | mutex_exit(p->p_lock); |
| 963 | mutex_enter(q->p_lock); |
| 964 | |
| 965 | if ((q->p_sflag & mask) == 0) |
| 966 | kpsignal2(q, &ksi); |
| 967 | |
| 968 | mutex_exit(q->p_lock); |
| 969 | mutex_enter(p->p_lock); |
| 970 | } |
| 971 | |
| 972 | void |
| 973 | psignal(struct proc *p, int signo) |
| 974 | { |
| 975 | ksiginfo_t ksi; |
| 976 | |
| 977 | KASSERT(!cpu_intr_p()); |
| 978 | KASSERT(mutex_owned(proc_lock)); |
| 979 | |
| 980 | KSI_INIT_EMPTY(&ksi); |
| 981 | ksi.ksi_signo = signo; |
| 982 | mutex_enter(p->p_lock); |
| 983 | kpsignal2(p, &ksi); |
| 984 | mutex_exit(p->p_lock); |
| 985 | } |
| 986 | |
| 987 | void |
| 988 | kpsignal(struct proc *p, ksiginfo_t *ksi, void *data) |
| 989 | { |
| 990 | fdfile_t *ff; |
| 991 | file_t *fp; |
| 992 | fdtab_t *dt; |
| 993 | |
| 994 | KASSERT(!cpu_intr_p()); |
| 995 | KASSERT(mutex_owned(proc_lock)); |
| 996 | |
| 997 | if ((p->p_sflag & PS_WEXIT) == 0 && data) { |
| 998 | size_t fd; |
| 999 | filedesc_t *fdp = p->p_fd; |
| 1000 | |
| 1001 | /* XXXSMP locking */ |
| 1002 | ksi->ksi_fd = -1; |
| 1003 | dt = fdp->fd_dt; |
| 1004 | for (fd = 0; fd < dt->dt_nfiles; fd++) { |
| 1005 | if ((ff = dt->dt_ff[fd]) == NULL) |
| 1006 | continue; |
| 1007 | if ((fp = ff->ff_file) == NULL) |
| 1008 | continue; |
| 1009 | if (fp->f_data == data) { |
| 1010 | ksi->ksi_fd = fd; |
| 1011 | break; |
| 1012 | } |
| 1013 | } |
| 1014 | } |
| 1015 | mutex_enter(p->p_lock); |
| 1016 | kpsignal2(p, ksi); |
| 1017 | mutex_exit(p->p_lock); |
| 1018 | } |
| 1019 | |
| 1020 | /* |
| 1021 | * sigismasked: |
| 1022 | * |
| 1023 | * Returns true if signal is ignored or masked for the specified LWP. |
| 1024 | */ |
| 1025 | int |
| 1026 | sigismasked(struct lwp *l, int sig) |
| 1027 | { |
| 1028 | struct proc *p = l->l_proc; |
| 1029 | |
| 1030 | return sigismember(&p->p_sigctx.ps_sigignore, sig) || |
| 1031 | sigismember(&l->l_sigmask, sig); |
| 1032 | } |
| 1033 | |
| 1034 | /* |
| 1035 | * sigpost: |
| 1036 | * |
| 1037 | * Post a pending signal to an LWP. Returns non-zero if the LWP may |
| 1038 | * be able to take the signal. |
| 1039 | */ |
| 1040 | static int |
| 1041 | sigpost(struct lwp *l, sig_t action, int prop, int sig) |
| 1042 | { |
| 1043 | int rv, masked; |
| 1044 | struct proc *p = l->l_proc; |
| 1045 | |
| 1046 | KASSERT(mutex_owned(p->p_lock)); |
| 1047 | |
| 1048 | /* |
| 1049 | * If the LWP is on the way out, sigclear() will be busy draining all |
| 1050 | * pending signals. Don't give it more. |
| 1051 | */ |
| 1052 | if (l->l_refcnt == 0) |
| 1053 | return 0; |
| 1054 | |
| 1055 | SDT_PROBE(proc, kernel, , signal__send, l, p, sig, 0, 0); |
| 1056 | |
| 1057 | /* |
| 1058 | * Have the LWP check for signals. This ensures that even if no LWP |
| 1059 | * is found to take the signal immediately, it should be taken soon. |
| 1060 | */ |
| 1061 | lwp_lock(l); |
| 1062 | l->l_flag |= LW_PENDSIG; |
| 1063 | |
| 1064 | /* |
| 1065 | * SIGCONT can be masked, but if LWP is stopped, it needs restart. |
| 1066 | * Note: SIGKILL and SIGSTOP cannot be masked. |
| 1067 | */ |
| 1068 | masked = sigismember(&l->l_sigmask, sig); |
| 1069 | if (masked && ((prop & SA_CONT) == 0 || l->l_stat != LSSTOP)) { |
| 1070 | lwp_unlock(l); |
| 1071 | return 0; |
| 1072 | } |
| 1073 | |
| 1074 | /* |
| 1075 | * If killing the process, make it run fast. |
| 1076 | */ |
| 1077 | if (__predict_false((prop & SA_KILL) != 0) && |
| 1078 | action == SIG_DFL && l->l_priority < MAXPRI_USER) { |
| 1079 | KASSERT(l->l_class == SCHED_OTHER); |
| 1080 | lwp_changepri(l, MAXPRI_USER); |
| 1081 | } |
| 1082 | |
| 1083 | /* |
| 1084 | * If the LWP is running or on a run queue, then we win. If it's |
| 1085 | * sleeping interruptably, wake it and make it take the signal. If |
| 1086 | * the sleep isn't interruptable, then the chances are it will get |
| 1087 | * to see the signal soon anyhow. If suspended, it can't take the |
| 1088 | * signal right now. If it's LWP private or for all LWPs, save it |
| 1089 | * for later; otherwise punt. |
| 1090 | */ |
| 1091 | rv = 0; |
| 1092 | |
| 1093 | switch (l->l_stat) { |
| 1094 | case LSRUN: |
| 1095 | case LSONPROC: |
| 1096 | lwp_need_userret(l); |
| 1097 | rv = 1; |
| 1098 | break; |
| 1099 | |
| 1100 | case LSSLEEP: |
| 1101 | if ((l->l_flag & LW_SINTR) != 0) { |
| 1102 | /* setrunnable() will release the lock. */ |
| 1103 | setrunnable(l); |
| 1104 | return 1; |
| 1105 | } |
| 1106 | break; |
| 1107 | |
| 1108 | case LSSUSPENDED: |
| 1109 | if ((prop & SA_KILL) != 0 && (l->l_flag & LW_WCORE) != 0) { |
| 1110 | /* lwp_continue() will release the lock. */ |
| 1111 | lwp_continue(l); |
| 1112 | return 1; |
| 1113 | } |
| 1114 | break; |
| 1115 | |
| 1116 | case LSSTOP: |
| 1117 | if ((prop & SA_STOP) != 0) |
| 1118 | break; |
| 1119 | |
| 1120 | /* |
| 1121 | * If the LWP is stopped and we are sending a continue |
| 1122 | * signal, then start it again. |
| 1123 | */ |
| 1124 | if ((prop & SA_CONT) != 0) { |
| 1125 | if (l->l_wchan != NULL) { |
| 1126 | l->l_stat = LSSLEEP; |
| 1127 | p->p_nrlwps++; |
| 1128 | rv = 1; |
| 1129 | break; |
| 1130 | } |
| 1131 | /* setrunnable() will release the lock. */ |
| 1132 | setrunnable(l); |
| 1133 | return 1; |
| 1134 | } else if (l->l_wchan == NULL || (l->l_flag & LW_SINTR) != 0) { |
| 1135 | /* setrunnable() will release the lock. */ |
| 1136 | setrunnable(l); |
| 1137 | return 1; |
| 1138 | } |
| 1139 | break; |
| 1140 | |
| 1141 | default: |
| 1142 | break; |
| 1143 | } |
| 1144 | |
| 1145 | lwp_unlock(l); |
| 1146 | return rv; |
| 1147 | } |
| 1148 | |
| 1149 | /* |
| 1150 | * Notify an LWP that it has a pending signal. |
| 1151 | */ |
| 1152 | void |
| 1153 | signotify(struct lwp *l) |
| 1154 | { |
| 1155 | KASSERT(lwp_locked(l, NULL)); |
| 1156 | |
| 1157 | l->l_flag |= LW_PENDSIG; |
| 1158 | lwp_need_userret(l); |
| 1159 | } |
| 1160 | |
| 1161 | /* |
| 1162 | * Find an LWP within process p that is waiting on signal ksi, and hand |
| 1163 | * it on. |
| 1164 | */ |
| 1165 | static int |
| 1166 | sigunwait(struct proc *p, const ksiginfo_t *ksi) |
| 1167 | { |
| 1168 | struct lwp *l; |
| 1169 | int signo; |
| 1170 | |
| 1171 | KASSERT(mutex_owned(p->p_lock)); |
| 1172 | |
| 1173 | signo = ksi->ksi_signo; |
| 1174 | |
| 1175 | if (ksi->ksi_lid != 0) { |
| 1176 | /* |
| 1177 | * Signal came via _lwp_kill(). Find the LWP and see if |
| 1178 | * it's interested. |
| 1179 | */ |
| 1180 | if ((l = lwp_find(p, ksi->ksi_lid)) == NULL) |
| 1181 | return 0; |
| 1182 | if (l->l_sigwaited == NULL || |
| 1183 | !sigismember(&l->l_sigwaitset, signo)) |
| 1184 | return 0; |
| 1185 | } else { |
| 1186 | /* |
| 1187 | * Look for any LWP that may be interested. |
| 1188 | */ |
| 1189 | LIST_FOREACH(l, &p->p_sigwaiters, l_sigwaiter) { |
| 1190 | KASSERT(l->l_sigwaited != NULL); |
| 1191 | if (sigismember(&l->l_sigwaitset, signo)) |
| 1192 | break; |
| 1193 | } |
| 1194 | } |
| 1195 | |
| 1196 | if (l != NULL) { |
| 1197 | l->l_sigwaited->ksi_info = ksi->ksi_info; |
| 1198 | l->l_sigwaited = NULL; |
| 1199 | LIST_REMOVE(l, l_sigwaiter); |
| 1200 | cv_signal(&l->l_sigcv); |
| 1201 | return 1; |
| 1202 | } |
| 1203 | |
| 1204 | return 0; |
| 1205 | } |
| 1206 | |
| 1207 | /* |
| 1208 | * Send the signal to the process. If the signal has an action, the action |
| 1209 | * is usually performed by the target process rather than the caller; we add |
| 1210 | * the signal to the set of pending signals for the process. |
| 1211 | * |
| 1212 | * Exceptions: |
| 1213 | * o When a stop signal is sent to a sleeping process that takes the |
| 1214 | * default action, the process is stopped without awakening it. |
| 1215 | * o SIGCONT restarts stopped processes (or puts them back to sleep) |
| 1216 | * regardless of the signal action (eg, blocked or ignored). |
| 1217 | * |
| 1218 | * Other ignored signals are discarded immediately. |
| 1219 | */ |
| 1220 | int |
| 1221 | kpsignal2(struct proc *p, ksiginfo_t *ksi) |
| 1222 | { |
| 1223 | int prop, signo = ksi->ksi_signo; |
| 1224 | struct sigacts *sa; |
| 1225 | struct lwp *l = NULL; |
| 1226 | ksiginfo_t *kp; |
| 1227 | lwpid_t lid; |
| 1228 | sig_t action; |
| 1229 | bool toall; |
| 1230 | int error = 0; |
| 1231 | |
| 1232 | KASSERT(!cpu_intr_p()); |
| 1233 | KASSERT(mutex_owned(proc_lock)); |
| 1234 | KASSERT(mutex_owned(p->p_lock)); |
| 1235 | KASSERT((ksi->ksi_flags & KSI_QUEUED) == 0); |
| 1236 | KASSERT(signo > 0 && signo < NSIG); |
| 1237 | |
| 1238 | /* |
| 1239 | * If the process is being created by fork, is a zombie or is |
| 1240 | * exiting, then just drop the signal here and bail out. |
| 1241 | */ |
| 1242 | if (p->p_stat != SACTIVE && p->p_stat != SSTOP) |
| 1243 | return 0; |
| 1244 | |
| 1245 | /* |
| 1246 | * Notify any interested parties of the signal. |
| 1247 | */ |
| 1248 | KNOTE(&p->p_klist, NOTE_SIGNAL | signo); |
| 1249 | |
| 1250 | /* |
| 1251 | * Some signals including SIGKILL must act on the entire process. |
| 1252 | */ |
| 1253 | kp = NULL; |
| 1254 | prop = sigprop[signo]; |
| 1255 | toall = ((prop & SA_TOALL) != 0); |
| 1256 | lid = toall ? 0 : ksi->ksi_lid; |
| 1257 | |
| 1258 | /* |
| 1259 | * If proc is traced, always give parent a chance. |
| 1260 | */ |
| 1261 | if (p->p_slflag & PSL_TRACED) { |
| 1262 | action = SIG_DFL; |
| 1263 | |
| 1264 | if (lid == 0) { |
| 1265 | /* |
| 1266 | * If the process is being traced and the signal |
| 1267 | * is being caught, make sure to save any ksiginfo. |
| 1268 | */ |
| 1269 | if ((kp = ksiginfo_alloc(p, ksi, PR_NOWAIT)) == NULL) |
| 1270 | goto discard; |
| 1271 | if ((error = sigput(&p->p_sigpend, p, kp)) != 0) |
| 1272 | goto out; |
| 1273 | } |
| 1274 | } else { |
| 1275 | /* |
| 1276 | * If the signal was the result of a trap and is not being |
| 1277 | * caught, then reset it to default action so that the |
| 1278 | * process dumps core immediately. |
| 1279 | */ |
| 1280 | if (KSI_TRAP_P(ksi)) { |
| 1281 | sa = p->p_sigacts; |
| 1282 | mutex_enter(&sa->sa_mutex); |
| 1283 | if (!sigismember(&p->p_sigctx.ps_sigcatch, signo)) { |
| 1284 | sigdelset(&p->p_sigctx.ps_sigignore, signo); |
| 1285 | SIGACTION(p, signo).sa_handler = SIG_DFL; |
| 1286 | } |
| 1287 | mutex_exit(&sa->sa_mutex); |
| 1288 | } |
| 1289 | |
| 1290 | /* |
| 1291 | * If the signal is being ignored, then drop it. Note: we |
| 1292 | * don't set SIGCONT in ps_sigignore, and if it is set to |
| 1293 | * SIG_IGN, action will be SIG_DFL here. |
| 1294 | */ |
| 1295 | if (sigismember(&p->p_sigctx.ps_sigignore, signo)) |
| 1296 | goto discard; |
| 1297 | |
| 1298 | else if (sigismember(&p->p_sigctx.ps_sigcatch, signo)) |
| 1299 | action = SIG_CATCH; |
| 1300 | else { |
| 1301 | action = SIG_DFL; |
| 1302 | |
| 1303 | /* |
| 1304 | * If sending a tty stop signal to a member of an |
| 1305 | * orphaned process group, discard the signal here if |
| 1306 | * the action is default; don't stop the process below |
| 1307 | * if sleeping, and don't clear any pending SIGCONT. |
| 1308 | */ |
| 1309 | if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0) |
| 1310 | goto discard; |
| 1311 | |
| 1312 | if (prop & SA_KILL && p->p_nice > NZERO) |
| 1313 | p->p_nice = NZERO; |
| 1314 | } |
| 1315 | } |
| 1316 | |
| 1317 | /* |
| 1318 | * If stopping or continuing a process, discard any pending |
| 1319 | * signals that would do the inverse. |
| 1320 | */ |
| 1321 | if ((prop & (SA_CONT | SA_STOP)) != 0) { |
| 1322 | ksiginfoq_t kq; |
| 1323 | |
| 1324 | ksiginfo_queue_init(&kq); |
| 1325 | if ((prop & SA_CONT) != 0) |
| 1326 | sigclear(&p->p_sigpend, &stopsigmask, &kq); |
| 1327 | if ((prop & SA_STOP) != 0) |
| 1328 | sigclear(&p->p_sigpend, &contsigmask, &kq); |
| 1329 | ksiginfo_queue_drain(&kq); /* XXXSMP */ |
| 1330 | } |
| 1331 | |
| 1332 | /* |
| 1333 | * If the signal doesn't have SA_CANTMASK (no override for SIGKILL, |
| 1334 | * please!), check if any LWPs are waiting on it. If yes, pass on |
| 1335 | * the signal info. The signal won't be processed further here. |
| 1336 | */ |
| 1337 | if ((prop & SA_CANTMASK) == 0 && !LIST_EMPTY(&p->p_sigwaiters) && |
| 1338 | p->p_stat == SACTIVE && (p->p_sflag & PS_STOPPING) == 0 && |
| 1339 | sigunwait(p, ksi)) |
| 1340 | goto discard; |
| 1341 | |
| 1342 | /* |
| 1343 | * XXXSMP Should be allocated by the caller, we're holding locks |
| 1344 | * here. |
| 1345 | */ |
| 1346 | if (kp == NULL && (kp = ksiginfo_alloc(p, ksi, PR_NOWAIT)) == NULL) |
| 1347 | goto discard; |
| 1348 | |
| 1349 | /* |
| 1350 | * LWP private signals are easy - just find the LWP and post |
| 1351 | * the signal to it. |
| 1352 | */ |
| 1353 | if (lid != 0) { |
| 1354 | l = lwp_find(p, lid); |
| 1355 | if (l != NULL) { |
| 1356 | if ((error = sigput(&l->l_sigpend, p, kp)) != 0) |
| 1357 | goto out; |
| 1358 | membar_producer(); |
| 1359 | (void)sigpost(l, action, prop, kp->ksi_signo); |
| 1360 | } |
| 1361 | goto out; |
| 1362 | } |
| 1363 | |
| 1364 | /* |
| 1365 | * Some signals go to all LWPs, even if posted with _lwp_kill() |
| 1366 | * or for an SA process. |
| 1367 | */ |
| 1368 | if (p->p_stat == SACTIVE && (p->p_sflag & PS_STOPPING) == 0) { |
| 1369 | if ((p->p_slflag & PSL_TRACED) != 0) |
| 1370 | goto deliver; |
| 1371 | |
| 1372 | /* |
| 1373 | * If SIGCONT is default (or ignored) and process is |
| 1374 | * asleep, we are finished; the process should not |
| 1375 | * be awakened. |
| 1376 | */ |
| 1377 | if ((prop & SA_CONT) != 0 && action == SIG_DFL) |
| 1378 | goto out; |
| 1379 | } else { |
| 1380 | /* |
| 1381 | * Process is stopped or stopping. |
| 1382 | * - If traced, then no action is needed, unless killing. |
| 1383 | * - Run the process only if sending SIGCONT or SIGKILL. |
| 1384 | */ |
| 1385 | if ((p->p_slflag & PSL_TRACED) != 0 && signo != SIGKILL) { |
| 1386 | goto out; |
| 1387 | } |
| 1388 | if ((prop & SA_CONT) != 0 || signo == SIGKILL) { |
| 1389 | /* |
| 1390 | * Re-adjust p_nstopchild if the process was |
| 1391 | * stopped but not yet collected by its parent. |
| 1392 | */ |
| 1393 | if (p->p_stat == SSTOP && !p->p_waited) |
| 1394 | p->p_pptr->p_nstopchild--; |
| 1395 | p->p_stat = SACTIVE; |
| 1396 | p->p_sflag &= ~PS_STOPPING; |
| 1397 | if (p->p_slflag & PSL_TRACED) { |
| 1398 | KASSERT(signo == SIGKILL); |
| 1399 | goto deliver; |
| 1400 | } |
| 1401 | /* |
| 1402 | * Do not make signal pending if SIGCONT is default. |
| 1403 | * |
| 1404 | * If the process catches SIGCONT, let it handle the |
| 1405 | * signal itself (if waiting on event - process runs, |
| 1406 | * otherwise continues sleeping). |
| 1407 | */ |
| 1408 | if ((prop & SA_CONT) != 0) { |
| 1409 | p->p_xsig = SIGCONT; |
| 1410 | p->p_sflag |= PS_CONTINUED; |
| 1411 | child_psignal(p, 0); |
| 1412 | if (action == SIG_DFL) { |
| 1413 | KASSERT(signo != SIGKILL); |
| 1414 | goto deliver; |
| 1415 | } |
| 1416 | } |
| 1417 | } else if ((prop & SA_STOP) != 0) { |
| 1418 | /* |
| 1419 | * Already stopped, don't need to stop again. |
| 1420 | * (If we did the shell could get confused.) |
| 1421 | */ |
| 1422 | goto out; |
| 1423 | } |
| 1424 | } |
| 1425 | /* |
| 1426 | * Make signal pending. |
| 1427 | */ |
| 1428 | KASSERT((p->p_slflag & PSL_TRACED) == 0); |
| 1429 | if ((error = sigput(&p->p_sigpend, p, kp)) != 0) |
| 1430 | goto out; |
| 1431 | deliver: |
| 1432 | /* |
| 1433 | * Before we set LW_PENDSIG on any LWP, ensure that the signal is |
| 1434 | * visible on the per process list (for sigispending()). This |
| 1435 | * is unlikely to be needed in practice, but... |
| 1436 | */ |
| 1437 | membar_producer(); |
| 1438 | |
| 1439 | /* |
| 1440 | * Try to find an LWP that can take the signal. |
| 1441 | */ |
| 1442 | LIST_FOREACH(l, &p->p_lwps, l_sibling) { |
| 1443 | if (sigpost(l, action, prop, kp->ksi_signo) && !toall) |
| 1444 | break; |
| 1445 | } |
| 1446 | signo = -1; |
| 1447 | out: |
| 1448 | /* |
| 1449 | * If the ksiginfo wasn't used, then bin it. XXXSMP freeing memory |
| 1450 | * with locks held. The caller should take care of this. |
| 1451 | */ |
| 1452 | ksiginfo_free(kp); |
| 1453 | if (signo == -1) |
| 1454 | return error; |
| 1455 | discard: |
| 1456 | SDT_PROBE(proc, kernel, , signal__discard, l, p, signo, 0, 0); |
| 1457 | return error; |
| 1458 | } |
| 1459 | |
| 1460 | void |
| 1461 | kpsendsig(struct lwp *l, const ksiginfo_t *ksi, const sigset_t *mask) |
| 1462 | { |
| 1463 | struct proc *p = l->l_proc; |
| 1464 | |
| 1465 | KASSERT(mutex_owned(p->p_lock)); |
| 1466 | (*p->p_emul->e_sendsig)(ksi, mask); |
| 1467 | } |
| 1468 | |
| 1469 | /* |
| 1470 | * Stop any LWPs sleeping interruptably. |
| 1471 | */ |
| 1472 | static void |
| 1473 | proc_stop_lwps(struct proc *p) |
| 1474 | { |
| 1475 | struct lwp *l; |
| 1476 | |
| 1477 | KASSERT(mutex_owned(p->p_lock)); |
| 1478 | KASSERT((p->p_sflag & PS_STOPPING) != 0); |
| 1479 | |
| 1480 | LIST_FOREACH(l, &p->p_lwps, l_sibling) { |
| 1481 | lwp_lock(l); |
| 1482 | if (l->l_stat == LSSLEEP && (l->l_flag & LW_SINTR) != 0) { |
| 1483 | l->l_stat = LSSTOP; |
| 1484 | p->p_nrlwps--; |
| 1485 | } |
| 1486 | lwp_unlock(l); |
| 1487 | } |
| 1488 | } |
| 1489 | |
| 1490 | /* |
| 1491 | * Finish stopping of a process. Mark it stopped and notify the parent. |
| 1492 | * |
| 1493 | * Drop p_lock briefly if PS_NOTIFYSTOP is set and ppsig is true. |
| 1494 | */ |
| 1495 | static void |
| 1496 | proc_stop_done(struct proc *p, bool ppsig, int ppmask) |
| 1497 | { |
| 1498 | |
| 1499 | KASSERT(mutex_owned(proc_lock)); |
| 1500 | KASSERT(mutex_owned(p->p_lock)); |
| 1501 | KASSERT((p->p_sflag & PS_STOPPING) != 0); |
| 1502 | KASSERT(p->p_nrlwps == 0 || (p->p_nrlwps == 1 && p == curproc)); |
| 1503 | |
| 1504 | p->p_sflag &= ~PS_STOPPING; |
| 1505 | p->p_stat = SSTOP; |
| 1506 | p->p_waited = 0; |
| 1507 | p->p_pptr->p_nstopchild++; |
| 1508 | if ((p->p_sflag & PS_NOTIFYSTOP) != 0) { |
| 1509 | if (ppsig) { |
| 1510 | /* child_psignal drops p_lock briefly. */ |
| 1511 | child_psignal(p, ppmask); |
| 1512 | } |
| 1513 | cv_broadcast(&p->p_pptr->p_waitcv); |
| 1514 | } |
| 1515 | } |
| 1516 | |
| 1517 | /* |
| 1518 | * Stop the current process and switch away when being stopped or traced. |
| 1519 | */ |
| 1520 | static void |
| 1521 | sigswitch(bool ppsig, int ppmask, int signo) |
| 1522 | { |
| 1523 | struct lwp *l = curlwp; |
| 1524 | struct proc *p = l->l_proc; |
| 1525 | int biglocks; |
| 1526 | |
| 1527 | KASSERT(mutex_owned(p->p_lock)); |
| 1528 | KASSERT(l->l_stat == LSONPROC); |
| 1529 | KASSERT(p->p_nrlwps > 0); |
| 1530 | |
| 1531 | /* |
| 1532 | * On entry we know that the process needs to stop. If it's |
| 1533 | * the result of a 'sideways' stop signal that has been sourced |
| 1534 | * through issignal(), then stop other LWPs in the process too. |
| 1535 | */ |
| 1536 | if (p->p_stat == SACTIVE && (p->p_sflag & PS_STOPPING) == 0) { |
| 1537 | KASSERT(signo != 0); |
| 1538 | proc_stop(p, 1, signo); |
| 1539 | KASSERT(p->p_nrlwps > 0); |
| 1540 | } |
| 1541 | |
| 1542 | /* |
| 1543 | * If we are the last live LWP, and the stop was a result of |
| 1544 | * a new signal, then signal the parent. |
| 1545 | */ |
| 1546 | if ((p->p_sflag & PS_STOPPING) != 0) { |
| 1547 | if (!mutex_tryenter(proc_lock)) { |
| 1548 | mutex_exit(p->p_lock); |
| 1549 | mutex_enter(proc_lock); |
| 1550 | mutex_enter(p->p_lock); |
| 1551 | } |
| 1552 | |
| 1553 | if (p->p_nrlwps == 1 && (p->p_sflag & PS_STOPPING) != 0) { |
| 1554 | /* |
| 1555 | * Note that proc_stop_done() can drop |
| 1556 | * p->p_lock briefly. |
| 1557 | */ |
| 1558 | proc_stop_done(p, ppsig, ppmask); |
| 1559 | } |
| 1560 | |
| 1561 | mutex_exit(proc_lock); |
| 1562 | } |
| 1563 | |
| 1564 | /* |
| 1565 | * Unlock and switch away. |
| 1566 | */ |
| 1567 | KERNEL_UNLOCK_ALL(l, &biglocks); |
| 1568 | if (p->p_stat == SSTOP || (p->p_sflag & PS_STOPPING) != 0) { |
| 1569 | p->p_nrlwps--; |
| 1570 | lwp_lock(l); |
| 1571 | KASSERT(l->l_stat == LSONPROC || l->l_stat == LSSLEEP); |
| 1572 | l->l_stat = LSSTOP; |
| 1573 | lwp_unlock(l); |
| 1574 | } |
| 1575 | |
| 1576 | mutex_exit(p->p_lock); |
| 1577 | lwp_lock(l); |
| 1578 | mi_switch(l); |
| 1579 | KERNEL_LOCK(biglocks, l); |
| 1580 | mutex_enter(p->p_lock); |
| 1581 | } |
| 1582 | |
| 1583 | /* |
| 1584 | * Check for a signal from the debugger. |
| 1585 | */ |
| 1586 | static int |
| 1587 | sigchecktrace(void) |
| 1588 | { |
| 1589 | struct lwp *l = curlwp; |
| 1590 | struct proc *p = l->l_proc; |
| 1591 | int signo; |
| 1592 | |
| 1593 | KASSERT(mutex_owned(p->p_lock)); |
| 1594 | |
| 1595 | /* If there's a pending SIGKILL, process it immediately. */ |
| 1596 | if (sigismember(&p->p_sigpend.sp_set, SIGKILL)) |
| 1597 | return 0; |
| 1598 | |
| 1599 | /* |
| 1600 | * If we are no longer being traced, or the parent didn't |
| 1601 | * give us a signal, or we're stopping, look for more signals. |
| 1602 | */ |
| 1603 | if ((p->p_slflag & PSL_TRACED) == 0 || p->p_xsig == 0 || |
| 1604 | (p->p_sflag & PS_STOPPING) != 0) |
| 1605 | return 0; |
| 1606 | |
| 1607 | /* |
| 1608 | * If the new signal is being masked, look for other signals. |
| 1609 | * `p->p_sigctx.ps_siglist |= mask' is done in setrunnable(). |
| 1610 | */ |
| 1611 | signo = p->p_xsig; |
| 1612 | p->p_xsig = 0; |
| 1613 | if (sigismember(&l->l_sigmask, signo)) { |
| 1614 | signo = 0; |
| 1615 | } |
| 1616 | return signo; |
| 1617 | } |
| 1618 | |
| 1619 | /* |
| 1620 | * If the current process has received a signal (should be caught or cause |
| 1621 | * termination, should interrupt current syscall), return the signal number. |
| 1622 | * |
| 1623 | * Stop signals with default action are processed immediately, then cleared; |
| 1624 | * they aren't returned. This is checked after each entry to the system for |
| 1625 | * a syscall or trap. |
| 1626 | * |
| 1627 | * We will also return -1 if the process is exiting and the current LWP must |
| 1628 | * follow suit. |
| 1629 | */ |
| 1630 | int |
| 1631 | issignal(struct lwp *l) |
| 1632 | { |
| 1633 | struct proc *p; |
| 1634 | int signo, prop; |
| 1635 | sigpend_t *sp; |
| 1636 | sigset_t ss; |
| 1637 | |
| 1638 | p = l->l_proc; |
| 1639 | sp = NULL; |
| 1640 | signo = 0; |
| 1641 | |
| 1642 | KASSERT(p == curproc); |
| 1643 | KASSERT(mutex_owned(p->p_lock)); |
| 1644 | |
| 1645 | for (;;) { |
| 1646 | /* Discard any signals that we have decided not to take. */ |
| 1647 | if (signo != 0) { |
| 1648 | (void)sigget(sp, NULL, signo, NULL); |
| 1649 | } |
| 1650 | |
| 1651 | /* |
| 1652 | * If the process is stopped/stopping, then stop ourselves |
| 1653 | * now that we're on the kernel/userspace boundary. When |
| 1654 | * we awaken, check for a signal from the debugger. |
| 1655 | */ |
| 1656 | if (p->p_stat == SSTOP || (p->p_sflag & PS_STOPPING) != 0) { |
| 1657 | sigswitch(true, PS_NOCLDSTOP, 0); |
| 1658 | signo = sigchecktrace(); |
| 1659 | } else |
| 1660 | signo = 0; |
| 1661 | |
| 1662 | /* Signals from the debugger are "out of band". */ |
| 1663 | sp = NULL; |
| 1664 | |
| 1665 | /* |
| 1666 | * If the debugger didn't provide a signal, find a pending |
| 1667 | * signal from our set. Check per-LWP signals first, and |
| 1668 | * then per-process. |
| 1669 | */ |
| 1670 | if (signo == 0) { |
| 1671 | sp = &l->l_sigpend; |
| 1672 | ss = sp->sp_set; |
| 1673 | if ((p->p_lflag & PL_PPWAIT) != 0) |
| 1674 | sigminusset(&stopsigmask, &ss); |
| 1675 | sigminusset(&l->l_sigmask, &ss); |
| 1676 | |
| 1677 | if ((signo = firstsig(&ss)) == 0) { |
| 1678 | sp = &p->p_sigpend; |
| 1679 | ss = sp->sp_set; |
| 1680 | if ((p->p_lflag & PL_PPWAIT) != 0) |
| 1681 | sigminusset(&stopsigmask, &ss); |
| 1682 | sigminusset(&l->l_sigmask, &ss); |
| 1683 | |
| 1684 | if ((signo = firstsig(&ss)) == 0) { |
| 1685 | /* |
| 1686 | * No signal pending - clear the |
| 1687 | * indicator and bail out. |
| 1688 | */ |
| 1689 | lwp_lock(l); |
| 1690 | l->l_flag &= ~LW_PENDSIG; |
| 1691 | lwp_unlock(l); |
| 1692 | sp = NULL; |
| 1693 | break; |
| 1694 | } |
| 1695 | } |
| 1696 | } |
| 1697 | |
| 1698 | /* |
| 1699 | * We should see pending but ignored signals only if |
| 1700 | * we are being traced. |
| 1701 | */ |
| 1702 | if (sigismember(&p->p_sigctx.ps_sigignore, signo) && |
| 1703 | (p->p_slflag & PSL_TRACED) == 0) { |
| 1704 | /* Discard the signal. */ |
| 1705 | continue; |
| 1706 | } |
| 1707 | |
| 1708 | /* |
| 1709 | * If traced, always stop, and stay stopped until released |
| 1710 | * by the debugger. If the our parent process is waiting |
| 1711 | * for us, don't hang as we could deadlock. |
| 1712 | */ |
| 1713 | if ((p->p_slflag & PSL_TRACED) != 0 && |
| 1714 | (p->p_lflag & PL_PPWAIT) == 0 && signo != SIGKILL) { |
| 1715 | /* |
| 1716 | * Take the signal, but don't remove it from the |
| 1717 | * siginfo queue, because the debugger can send |
| 1718 | * it later. |
| 1719 | */ |
| 1720 | if (sp) |
| 1721 | sigdelset(&sp->sp_set, signo); |
| 1722 | p->p_xsig = signo; |
| 1723 | |
| 1724 | /* Emulation-specific handling of signal trace */ |
| 1725 | if (p->p_emul->e_tracesig == NULL || |
| 1726 | (*p->p_emul->e_tracesig)(p, signo) == 0) |
| 1727 | sigswitch(!(p->p_slflag & PSL_FSTRACE), 0, |
| 1728 | signo); |
| 1729 | |
| 1730 | /* Check for a signal from the debugger. */ |
| 1731 | if ((signo = sigchecktrace()) == 0) |
| 1732 | continue; |
| 1733 | |
| 1734 | /* Signals from the debugger are "out of band". */ |
| 1735 | sp = NULL; |
| 1736 | } |
| 1737 | |
| 1738 | prop = sigprop[signo]; |
| 1739 | |
| 1740 | /* |
| 1741 | * Decide whether the signal should be returned. |
| 1742 | */ |
| 1743 | switch ((long)SIGACTION(p, signo).sa_handler) { |
| 1744 | case (long)SIG_DFL: |
| 1745 | /* |
| 1746 | * Don't take default actions on system processes. |
| 1747 | */ |
| 1748 | if (p->p_pid <= 1) { |
| 1749 | #ifdef DIAGNOSTIC |
| 1750 | /* |
| 1751 | * Are you sure you want to ignore SIGSEGV |
| 1752 | * in init? XXX |
| 1753 | */ |
| 1754 | printf_nolog("Process (pid %d) got sig %d\n" , |
| 1755 | p->p_pid, signo); |
| 1756 | #endif |
| 1757 | continue; |
| 1758 | } |
| 1759 | |
| 1760 | /* |
| 1761 | * If there is a pending stop signal to process with |
| 1762 | * default action, stop here, then clear the signal. |
| 1763 | * However, if process is member of an orphaned |
| 1764 | * process group, ignore tty stop signals. |
| 1765 | */ |
| 1766 | if (prop & SA_STOP) { |
| 1767 | /* |
| 1768 | * XXX Don't hold proc_lock for p_lflag, |
| 1769 | * but it's not a big deal. |
| 1770 | */ |
| 1771 | if (p->p_slflag & PSL_TRACED || |
| 1772 | ((p->p_lflag & PL_ORPHANPG) != 0 && |
| 1773 | prop & SA_TTYSTOP)) { |
| 1774 | /* Ignore the signal. */ |
| 1775 | continue; |
| 1776 | } |
| 1777 | /* Take the signal. */ |
| 1778 | (void)sigget(sp, NULL, signo, NULL); |
| 1779 | p->p_xsig = signo; |
| 1780 | p->p_sflag &= ~PS_CONTINUED; |
| 1781 | signo = 0; |
| 1782 | sigswitch(true, PS_NOCLDSTOP, p->p_xsig); |
| 1783 | } else if (prop & SA_IGNORE) { |
| 1784 | /* |
| 1785 | * Except for SIGCONT, shouldn't get here. |
| 1786 | * Default action is to ignore; drop it. |
| 1787 | */ |
| 1788 | continue; |
| 1789 | } |
| 1790 | break; |
| 1791 | |
| 1792 | case (long)SIG_IGN: |
| 1793 | #ifdef DEBUG_ISSIGNAL |
| 1794 | /* |
| 1795 | * Masking above should prevent us ever trying |
| 1796 | * to take action on an ignored signal other |
| 1797 | * than SIGCONT, unless process is traced. |
| 1798 | */ |
| 1799 | if ((prop & SA_CONT) == 0 && |
| 1800 | (p->p_slflag & PSL_TRACED) == 0) |
| 1801 | printf_nolog("issignal\n" ); |
| 1802 | #endif |
| 1803 | continue; |
| 1804 | |
| 1805 | default: |
| 1806 | /* |
| 1807 | * This signal has an action, let postsig() process |
| 1808 | * it. |
| 1809 | */ |
| 1810 | break; |
| 1811 | } |
| 1812 | |
| 1813 | break; |
| 1814 | } |
| 1815 | |
| 1816 | l->l_sigpendset = sp; |
| 1817 | return signo; |
| 1818 | } |
| 1819 | |
| 1820 | /* |
| 1821 | * Take the action for the specified signal |
| 1822 | * from the current set of pending signals. |
| 1823 | */ |
| 1824 | void |
| 1825 | postsig(int signo) |
| 1826 | { |
| 1827 | struct lwp *l; |
| 1828 | struct proc *p; |
| 1829 | struct sigacts *ps; |
| 1830 | sig_t action; |
| 1831 | sigset_t *returnmask; |
| 1832 | ksiginfo_t ksi; |
| 1833 | |
| 1834 | l = curlwp; |
| 1835 | p = l->l_proc; |
| 1836 | ps = p->p_sigacts; |
| 1837 | |
| 1838 | KASSERT(mutex_owned(p->p_lock)); |
| 1839 | KASSERT(signo > 0); |
| 1840 | |
| 1841 | /* |
| 1842 | * Set the new mask value and also defer further occurrences of this |
| 1843 | * signal. |
| 1844 | * |
| 1845 | * Special case: user has done a sigsuspend. Here the current mask is |
| 1846 | * not of interest, but rather the mask from before the sigsuspend is |
| 1847 | * what we want restored after the signal processing is completed. |
| 1848 | */ |
| 1849 | if (l->l_sigrestore) { |
| 1850 | returnmask = &l->l_sigoldmask; |
| 1851 | l->l_sigrestore = 0; |
| 1852 | } else |
| 1853 | returnmask = &l->l_sigmask; |
| 1854 | |
| 1855 | /* |
| 1856 | * Commit to taking the signal before releasing the mutex. |
| 1857 | */ |
| 1858 | action = SIGACTION_PS(ps, signo).sa_handler; |
| 1859 | l->l_ru.ru_nsignals++; |
| 1860 | if (l->l_sigpendset == NULL) { |
| 1861 | /* From the debugger */ |
| 1862 | if (!siggetinfo(&l->l_sigpend, &ksi, signo)) |
| 1863 | (void)siggetinfo(&p->p_sigpend, &ksi, signo); |
| 1864 | } else |
| 1865 | sigget(l->l_sigpendset, &ksi, signo, NULL); |
| 1866 | |
| 1867 | if (ktrpoint(KTR_PSIG)) { |
| 1868 | mutex_exit(p->p_lock); |
| 1869 | if (p->p_emul->e_ktrpsig) |
| 1870 | p->p_emul->e_ktrpsig(signo, action, |
| 1871 | returnmask, &ksi); |
| 1872 | else |
| 1873 | ktrpsig(signo, action, returnmask, &ksi); |
| 1874 | mutex_enter(p->p_lock); |
| 1875 | } |
| 1876 | |
| 1877 | SDT_PROBE(proc, kernel, , signal__handle, signo, &ksi, action, 0, 0); |
| 1878 | |
| 1879 | if (action == SIG_DFL) { |
| 1880 | /* |
| 1881 | * Default action, where the default is to kill |
| 1882 | * the process. (Other cases were ignored above.) |
| 1883 | */ |
| 1884 | sigexit(l, signo); |
| 1885 | return; |
| 1886 | } |
| 1887 | |
| 1888 | /* |
| 1889 | * If we get here, the signal must be caught. |
| 1890 | */ |
| 1891 | #ifdef DIAGNOSTIC |
| 1892 | if (action == SIG_IGN || sigismember(&l->l_sigmask, signo)) |
| 1893 | panic("postsig action" ); |
| 1894 | #endif |
| 1895 | |
| 1896 | kpsendsig(l, &ksi, returnmask); |
| 1897 | } |
| 1898 | |
| 1899 | /* |
| 1900 | * sendsig: |
| 1901 | * |
| 1902 | * Default signal delivery method for NetBSD. |
| 1903 | */ |
| 1904 | void |
| 1905 | sendsig(const struct ksiginfo *ksi, const sigset_t *mask) |
| 1906 | { |
| 1907 | struct sigacts *sa; |
| 1908 | int sig; |
| 1909 | |
| 1910 | sig = ksi->ksi_signo; |
| 1911 | sa = curproc->p_sigacts; |
| 1912 | |
| 1913 | switch (sa->sa_sigdesc[sig].sd_vers) { |
| 1914 | case 0: |
| 1915 | case 1: |
| 1916 | /* Compat for 1.6 and earlier. */ |
| 1917 | if (sendsig_sigcontext_vec == NULL) { |
| 1918 | break; |
| 1919 | } |
| 1920 | (*sendsig_sigcontext_vec)(ksi, mask); |
| 1921 | return; |
| 1922 | case 2: |
| 1923 | case 3: |
| 1924 | sendsig_siginfo(ksi, mask); |
| 1925 | return; |
| 1926 | default: |
| 1927 | break; |
| 1928 | } |
| 1929 | |
| 1930 | printf("sendsig: bad version %d\n" , sa->sa_sigdesc[sig].sd_vers); |
| 1931 | sigexit(curlwp, SIGILL); |
| 1932 | } |
| 1933 | |
| 1934 | /* |
| 1935 | * sendsig_reset: |
| 1936 | * |
| 1937 | * Reset the signal action. Called from emulation specific sendsig() |
| 1938 | * before unlocking to deliver the signal. |
| 1939 | */ |
| 1940 | void |
| 1941 | sendsig_reset(struct lwp *l, int signo) |
| 1942 | { |
| 1943 | struct proc *p = l->l_proc; |
| 1944 | struct sigacts *ps = p->p_sigacts; |
| 1945 | |
| 1946 | KASSERT(mutex_owned(p->p_lock)); |
| 1947 | |
| 1948 | p->p_sigctx.ps_lwp = 0; |
| 1949 | p->p_sigctx.ps_code = 0; |
| 1950 | p->p_sigctx.ps_signo = 0; |
| 1951 | |
| 1952 | mutex_enter(&ps->sa_mutex); |
| 1953 | sigplusset(&SIGACTION_PS(ps, signo).sa_mask, &l->l_sigmask); |
| 1954 | if (SIGACTION_PS(ps, signo).sa_flags & SA_RESETHAND) { |
| 1955 | sigdelset(&p->p_sigctx.ps_sigcatch, signo); |
| 1956 | if (signo != SIGCONT && sigprop[signo] & SA_IGNORE) |
| 1957 | sigaddset(&p->p_sigctx.ps_sigignore, signo); |
| 1958 | SIGACTION_PS(ps, signo).sa_handler = SIG_DFL; |
| 1959 | } |
| 1960 | mutex_exit(&ps->sa_mutex); |
| 1961 | } |
| 1962 | |
| 1963 | /* |
| 1964 | * Kill the current process for stated reason. |
| 1965 | */ |
| 1966 | void |
| 1967 | killproc(struct proc *p, const char *why) |
| 1968 | { |
| 1969 | |
| 1970 | KASSERT(mutex_owned(proc_lock)); |
| 1971 | |
| 1972 | log(LOG_ERR, "pid %d was killed: %s\n" , p->p_pid, why); |
| 1973 | uprintf_locked("sorry, pid %d was killed: %s\n" , p->p_pid, why); |
| 1974 | psignal(p, SIGKILL); |
| 1975 | } |
| 1976 | |
| 1977 | /* |
| 1978 | * Force the current process to exit with the specified signal, dumping core |
| 1979 | * if appropriate. We bypass the normal tests for masked and caught |
| 1980 | * signals, allowing unrecoverable failures to terminate the process without |
| 1981 | * changing signal state. Mark the accounting record with the signal |
| 1982 | * termination. If dumping core, save the signal number for the debugger. |
| 1983 | * Calls exit and does not return. |
| 1984 | */ |
| 1985 | void |
| 1986 | sigexit(struct lwp *l, int signo) |
| 1987 | { |
| 1988 | int exitsig, error, docore; |
| 1989 | struct proc *p; |
| 1990 | struct lwp *t; |
| 1991 | |
| 1992 | p = l->l_proc; |
| 1993 | |
| 1994 | KASSERT(mutex_owned(p->p_lock)); |
| 1995 | KERNEL_UNLOCK_ALL(l, NULL); |
| 1996 | |
| 1997 | /* |
| 1998 | * Don't permit coredump() multiple times in the same process. |
| 1999 | * Call back into sigexit, where we will be suspended until |
| 2000 | * the deed is done. Note that this is a recursive call, but |
| 2001 | * LW_WCORE will prevent us from coming back this way. |
| 2002 | */ |
| 2003 | if ((p->p_sflag & PS_WCORE) != 0) { |
| 2004 | lwp_lock(l); |
| 2005 | l->l_flag |= (LW_WCORE | LW_WEXIT | LW_WSUSPEND); |
| 2006 | lwp_unlock(l); |
| 2007 | mutex_exit(p->p_lock); |
| 2008 | lwp_userret(l); |
| 2009 | panic("sigexit 1" ); |
| 2010 | /* NOTREACHED */ |
| 2011 | } |
| 2012 | |
| 2013 | /* If process is already on the way out, then bail now. */ |
| 2014 | if ((p->p_sflag & PS_WEXIT) != 0) { |
| 2015 | mutex_exit(p->p_lock); |
| 2016 | lwp_exit(l); |
| 2017 | panic("sigexit 2" ); |
| 2018 | /* NOTREACHED */ |
| 2019 | } |
| 2020 | |
| 2021 | /* |
| 2022 | * Prepare all other LWPs for exit. If dumping core, suspend them |
| 2023 | * so that their registers are available long enough to be dumped. |
| 2024 | */ |
| 2025 | if ((docore = (sigprop[signo] & SA_CORE)) != 0) { |
| 2026 | p->p_sflag |= PS_WCORE; |
| 2027 | for (;;) { |
| 2028 | LIST_FOREACH(t, &p->p_lwps, l_sibling) { |
| 2029 | lwp_lock(t); |
| 2030 | if (t == l) { |
| 2031 | t->l_flag &= ~LW_WSUSPEND; |
| 2032 | lwp_unlock(t); |
| 2033 | continue; |
| 2034 | } |
| 2035 | t->l_flag |= (LW_WCORE | LW_WEXIT); |
| 2036 | lwp_suspend(l, t); |
| 2037 | } |
| 2038 | |
| 2039 | if (p->p_nrlwps == 1) |
| 2040 | break; |
| 2041 | |
| 2042 | /* |
| 2043 | * Kick any LWPs sitting in lwp_wait1(), and wait |
| 2044 | * for everyone else to stop before proceeding. |
| 2045 | */ |
| 2046 | p->p_nlwpwait++; |
| 2047 | cv_broadcast(&p->p_lwpcv); |
| 2048 | cv_wait(&p->p_lwpcv, p->p_lock); |
| 2049 | p->p_nlwpwait--; |
| 2050 | } |
| 2051 | } |
| 2052 | |
| 2053 | exitsig = signo; |
| 2054 | p->p_acflag |= AXSIG; |
| 2055 | p->p_sigctx.ps_signo = signo; |
| 2056 | |
| 2057 | if (docore) { |
| 2058 | mutex_exit(p->p_lock); |
| 2059 | error = (*coredump_vec)(l, NULL); |
| 2060 | |
| 2061 | if (kern_logsigexit) { |
| 2062 | int uid = l->l_cred ? |
| 2063 | (int)kauth_cred_geteuid(l->l_cred) : -1; |
| 2064 | |
| 2065 | if (error) |
| 2066 | log(LOG_INFO, lognocoredump, p->p_pid, |
| 2067 | p->p_comm, uid, signo, error); |
| 2068 | else |
| 2069 | log(LOG_INFO, logcoredump, p->p_pid, |
| 2070 | p->p_comm, uid, signo); |
| 2071 | } |
| 2072 | |
| 2073 | #ifdef PAX_SEGVGUARD |
| 2074 | pax_segvguard(l, p->p_textvp, p->p_comm, true); |
| 2075 | #endif /* PAX_SEGVGUARD */ |
| 2076 | /* Acquire the sched state mutex. exit1() will release it. */ |
| 2077 | mutex_enter(p->p_lock); |
| 2078 | if (error == 0) |
| 2079 | p->p_sflag |= PS_COREDUMP; |
| 2080 | } |
| 2081 | |
| 2082 | /* No longer dumping core. */ |
| 2083 | p->p_sflag &= ~PS_WCORE; |
| 2084 | |
| 2085 | exit1(l, 0, exitsig); |
| 2086 | /* NOTREACHED */ |
| 2087 | } |
| 2088 | |
| 2089 | /* |
| 2090 | * Put process 'p' into the stopped state and optionally, notify the parent. |
| 2091 | */ |
| 2092 | void |
| 2093 | proc_stop(struct proc *p, int notify, int signo) |
| 2094 | { |
| 2095 | struct lwp *l; |
| 2096 | |
| 2097 | KASSERT(mutex_owned(p->p_lock)); |
| 2098 | |
| 2099 | /* |
| 2100 | * First off, set the stopping indicator and bring all sleeping |
| 2101 | * LWPs to a halt so they are included in p->p_nrlwps. We musn't |
| 2102 | * unlock between here and the p->p_nrlwps check below. |
| 2103 | */ |
| 2104 | p->p_sflag |= PS_STOPPING; |
| 2105 | if (notify) |
| 2106 | p->p_sflag |= PS_NOTIFYSTOP; |
| 2107 | else |
| 2108 | p->p_sflag &= ~PS_NOTIFYSTOP; |
| 2109 | membar_producer(); |
| 2110 | |
| 2111 | proc_stop_lwps(p); |
| 2112 | |
| 2113 | /* |
| 2114 | * If there are no LWPs available to take the signal, then we |
| 2115 | * signal the parent process immediately. Otherwise, the last |
| 2116 | * LWP to stop will take care of it. |
| 2117 | */ |
| 2118 | |
| 2119 | if (p->p_nrlwps == 0) { |
| 2120 | proc_stop_done(p, true, PS_NOCLDSTOP); |
| 2121 | } else { |
| 2122 | /* |
| 2123 | * Have the remaining LWPs come to a halt, and trigger |
| 2124 | * proc_stop_callout() to ensure that they do. |
| 2125 | */ |
| 2126 | LIST_FOREACH(l, &p->p_lwps, l_sibling) { |
| 2127 | sigpost(l, SIG_DFL, SA_STOP, signo); |
| 2128 | } |
| 2129 | callout_schedule(&proc_stop_ch, 1); |
| 2130 | } |
| 2131 | } |
| 2132 | |
| 2133 | /* |
| 2134 | * When stopping a process, we do not immediatly set sleeping LWPs stopped, |
| 2135 | * but wait for them to come to a halt at the kernel-user boundary. This is |
| 2136 | * to allow LWPs to release any locks that they may hold before stopping. |
| 2137 | * |
| 2138 | * Non-interruptable sleeps can be long, and there is the potential for an |
| 2139 | * LWP to begin sleeping interruptably soon after the process has been set |
| 2140 | * stopping (PS_STOPPING). These LWPs will not notice that the process is |
| 2141 | * stopping, and so complete halt of the process and the return of status |
| 2142 | * information to the parent could be delayed indefinitely. |
| 2143 | * |
| 2144 | * To handle this race, proc_stop_callout() runs once per tick while there |
| 2145 | * are stopping processes in the system. It sets LWPs that are sleeping |
| 2146 | * interruptably into the LSSTOP state. |
| 2147 | * |
| 2148 | * Note that we are not concerned about keeping all LWPs stopped while the |
| 2149 | * process is stopped: stopped LWPs can awaken briefly to handle signals. |
| 2150 | * What we do need to ensure is that all LWPs in a stopping process have |
| 2151 | * stopped at least once, so that notification can be sent to the parent |
| 2152 | * process. |
| 2153 | */ |
| 2154 | static void |
| 2155 | proc_stop_callout(void *cookie) |
| 2156 | { |
| 2157 | bool more, restart; |
| 2158 | struct proc *p; |
| 2159 | |
| 2160 | (void)cookie; |
| 2161 | |
| 2162 | do { |
| 2163 | restart = false; |
| 2164 | more = false; |
| 2165 | |
| 2166 | mutex_enter(proc_lock); |
| 2167 | PROCLIST_FOREACH(p, &allproc) { |
| 2168 | mutex_enter(p->p_lock); |
| 2169 | |
| 2170 | if ((p->p_sflag & PS_STOPPING) == 0) { |
| 2171 | mutex_exit(p->p_lock); |
| 2172 | continue; |
| 2173 | } |
| 2174 | |
| 2175 | /* Stop any LWPs sleeping interruptably. */ |
| 2176 | proc_stop_lwps(p); |
| 2177 | if (p->p_nrlwps == 0) { |
| 2178 | /* |
| 2179 | * We brought the process to a halt. |
| 2180 | * Mark it as stopped and notify the |
| 2181 | * parent. |
| 2182 | */ |
| 2183 | if ((p->p_sflag & PS_NOTIFYSTOP) != 0) { |
| 2184 | /* |
| 2185 | * Note that proc_stop_done() will |
| 2186 | * drop p->p_lock briefly. |
| 2187 | * Arrange to restart and check |
| 2188 | * all processes again. |
| 2189 | */ |
| 2190 | restart = true; |
| 2191 | } |
| 2192 | proc_stop_done(p, true, PS_NOCLDSTOP); |
| 2193 | } else |
| 2194 | more = true; |
| 2195 | |
| 2196 | mutex_exit(p->p_lock); |
| 2197 | if (restart) |
| 2198 | break; |
| 2199 | } |
| 2200 | mutex_exit(proc_lock); |
| 2201 | } while (restart); |
| 2202 | |
| 2203 | /* |
| 2204 | * If we noted processes that are stopping but still have |
| 2205 | * running LWPs, then arrange to check again in 1 tick. |
| 2206 | */ |
| 2207 | if (more) |
| 2208 | callout_schedule(&proc_stop_ch, 1); |
| 2209 | } |
| 2210 | |
| 2211 | /* |
| 2212 | * Given a process in state SSTOP, set the state back to SACTIVE and |
| 2213 | * move LSSTOP'd LWPs to LSSLEEP or make them runnable. |
| 2214 | */ |
| 2215 | void |
| 2216 | proc_unstop(struct proc *p) |
| 2217 | { |
| 2218 | struct lwp *l; |
| 2219 | int sig; |
| 2220 | |
| 2221 | KASSERT(mutex_owned(proc_lock)); |
| 2222 | KASSERT(mutex_owned(p->p_lock)); |
| 2223 | |
| 2224 | p->p_stat = SACTIVE; |
| 2225 | p->p_sflag &= ~PS_STOPPING; |
| 2226 | sig = p->p_xsig; |
| 2227 | |
| 2228 | if (!p->p_waited) |
| 2229 | p->p_pptr->p_nstopchild--; |
| 2230 | |
| 2231 | LIST_FOREACH(l, &p->p_lwps, l_sibling) { |
| 2232 | lwp_lock(l); |
| 2233 | if (l->l_stat != LSSTOP) { |
| 2234 | lwp_unlock(l); |
| 2235 | continue; |
| 2236 | } |
| 2237 | if (l->l_wchan == NULL) { |
| 2238 | setrunnable(l); |
| 2239 | continue; |
| 2240 | } |
| 2241 | if (sig && (l->l_flag & LW_SINTR) != 0) { |
| 2242 | setrunnable(l); |
| 2243 | sig = 0; |
| 2244 | } else { |
| 2245 | l->l_stat = LSSLEEP; |
| 2246 | p->p_nrlwps++; |
| 2247 | lwp_unlock(l); |
| 2248 | } |
| 2249 | } |
| 2250 | } |
| 2251 | |
| 2252 | static int |
| 2253 | filt_sigattach(struct knote *kn) |
| 2254 | { |
| 2255 | struct proc *p = curproc; |
| 2256 | |
| 2257 | kn->kn_obj = p; |
| 2258 | kn->kn_flags |= EV_CLEAR; /* automatically set */ |
| 2259 | |
| 2260 | mutex_enter(p->p_lock); |
| 2261 | SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); |
| 2262 | mutex_exit(p->p_lock); |
| 2263 | |
| 2264 | return 0; |
| 2265 | } |
| 2266 | |
| 2267 | static void |
| 2268 | filt_sigdetach(struct knote *kn) |
| 2269 | { |
| 2270 | struct proc *p = kn->kn_obj; |
| 2271 | |
| 2272 | mutex_enter(p->p_lock); |
| 2273 | SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); |
| 2274 | mutex_exit(p->p_lock); |
| 2275 | } |
| 2276 | |
| 2277 | /* |
| 2278 | * Signal knotes are shared with proc knotes, so we apply a mask to |
| 2279 | * the hint in order to differentiate them from process hints. This |
| 2280 | * could be avoided by using a signal-specific knote list, but probably |
| 2281 | * isn't worth the trouble. |
| 2282 | */ |
| 2283 | static int |
| 2284 | filt_signal(struct knote *kn, long hint) |
| 2285 | { |
| 2286 | |
| 2287 | if (hint & NOTE_SIGNAL) { |
| 2288 | hint &= ~NOTE_SIGNAL; |
| 2289 | |
| 2290 | if (kn->kn_id == hint) |
| 2291 | kn->kn_data++; |
| 2292 | } |
| 2293 | return (kn->kn_data != 0); |
| 2294 | } |
| 2295 | |
| 2296 | const struct filterops sig_filtops = { |
| 2297 | 0, filt_sigattach, filt_sigdetach, filt_signal |
| 2298 | }; |
| 2299 | |