| 1 | /* $NetBSD: kern_exit.c,v 1.267 2016/11/13 15:25:01 christos Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 1998, 1999, 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 Jason R. Thorpe of the Numerical Aerospace Simulation Facility, |
| 9 | * NASA Ames Research Center, and by Andrew Doran. |
| 10 | * |
| 11 | * Redistribution and use in source and binary forms, with or without |
| 12 | * modification, are permitted provided that the following conditions |
| 13 | * are met: |
| 14 | * 1. Redistributions of source code must retain the above copyright |
| 15 | * notice, this list of conditions and the following disclaimer. |
| 16 | * 2. Redistributions in binary form must reproduce the above copyright |
| 17 | * notice, this list of conditions and the following disclaimer in the |
| 18 | * documentation and/or other materials provided with the distribution. |
| 19 | * |
| 20 | * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS |
| 21 | * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED |
| 22 | * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
| 23 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS |
| 24 | * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
| 25 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
| 26 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
| 27 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
| 28 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
| 29 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
| 30 | * POSSIBILITY OF SUCH DAMAGE. |
| 31 | */ |
| 32 | |
| 33 | /* |
| 34 | * Copyright (c) 1982, 1986, 1989, 1991, 1993 |
| 35 | * The Regents of the University of California. All rights reserved. |
| 36 | * (c) UNIX System Laboratories, Inc. |
| 37 | * All or some portions of this file are derived from material licensed |
| 38 | * to the University of California by American Telephone and Telegraph |
| 39 | * Co. or Unix System Laboratories, Inc. and are reproduced herein with |
| 40 | * the permission of UNIX System Laboratories, Inc. |
| 41 | * |
| 42 | * Redistribution and use in source and binary forms, with or without |
| 43 | * modification, are permitted provided that the following conditions |
| 44 | * are met: |
| 45 | * 1. Redistributions of source code must retain the above copyright |
| 46 | * notice, this list of conditions and the following disclaimer. |
| 47 | * 2. Redistributions in binary form must reproduce the above copyright |
| 48 | * notice, this list of conditions and the following disclaimer in the |
| 49 | * documentation and/or other materials provided with the distribution. |
| 50 | * 3. Neither the name of the University nor the names of its contributors |
| 51 | * may be used to endorse or promote products derived from this software |
| 52 | * without specific prior written permission. |
| 53 | * |
| 54 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 55 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 56 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 57 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 58 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 59 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 60 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 61 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 62 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 63 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 64 | * SUCH DAMAGE. |
| 65 | * |
| 66 | * @(#)kern_exit.c 8.10 (Berkeley) 2/23/95 |
| 67 | */ |
| 68 | |
| 69 | #include <sys/cdefs.h> |
| 70 | __KERNEL_RCSID(0, "$NetBSD: kern_exit.c,v 1.267 2016/11/13 15:25:01 christos Exp $" ); |
| 71 | |
| 72 | #include "opt_ktrace.h" |
| 73 | #include "opt_dtrace.h" |
| 74 | #include "opt_perfctrs.h" |
| 75 | #include "opt_sysv.h" |
| 76 | |
| 77 | #include <sys/param.h> |
| 78 | #include <sys/systm.h> |
| 79 | #include <sys/ioctl.h> |
| 80 | #include <sys/tty.h> |
| 81 | #include <sys/time.h> |
| 82 | #include <sys/resource.h> |
| 83 | #include <sys/kernel.h> |
| 84 | #include <sys/proc.h> |
| 85 | #include <sys/buf.h> |
| 86 | #include <sys/wait.h> |
| 87 | #include <sys/file.h> |
| 88 | #include <sys/vnode.h> |
| 89 | #include <sys/syslog.h> |
| 90 | #include <sys/pool.h> |
| 91 | #include <sys/uidinfo.h> |
| 92 | #if defined(PERFCTRS) |
| 93 | #include <sys/pmc.h> |
| 94 | #endif |
| 95 | #include <sys/ptrace.h> |
| 96 | #include <sys/acct.h> |
| 97 | #include <sys/filedesc.h> |
| 98 | #include <sys/ras.h> |
| 99 | #include <sys/signalvar.h> |
| 100 | #include <sys/sched.h> |
| 101 | #include <sys/mount.h> |
| 102 | #include <sys/syscallargs.h> |
| 103 | #include <sys/kauth.h> |
| 104 | #include <sys/sleepq.h> |
| 105 | #include <sys/lockdebug.h> |
| 106 | #include <sys/ktrace.h> |
| 107 | #include <sys/cpu.h> |
| 108 | #include <sys/lwpctl.h> |
| 109 | #include <sys/atomic.h> |
| 110 | #include <sys/sdt.h> |
| 111 | |
| 112 | #include <uvm/uvm_extern.h> |
| 113 | |
| 114 | #ifdef DEBUG_EXIT |
| 115 | int debug_exit = 0; |
| 116 | #define DPRINTF(x) if (debug_exit) printf x |
| 117 | #else |
| 118 | #define DPRINTF(x) |
| 119 | #endif |
| 120 | |
| 121 | static int find_stopped_child(struct proc *, idtype_t, id_t, int, |
| 122 | struct proc **, struct wrusage *, siginfo_t *); |
| 123 | static void proc_free(struct proc *, struct wrusage *); |
| 124 | |
| 125 | /* |
| 126 | * DTrace SDT provider definitions |
| 127 | */ |
| 128 | SDT_PROVIDER_DECLARE(proc); |
| 129 | SDT_PROBE_DEFINE1(proc, kernel, , exit, "int" ); |
| 130 | |
| 131 | /* |
| 132 | * Fill in the appropriate signal information, and signal the parent. |
| 133 | */ |
| 134 | /* XXX noclone works around a gcc 4.5 bug on arm */ |
| 135 | static void __noclone |
| 136 | exit_psignal(struct proc *p, struct proc *pp, ksiginfo_t *ksi) |
| 137 | { |
| 138 | |
| 139 | KSI_INIT(ksi); |
| 140 | if ((ksi->ksi_signo = P_EXITSIG(p)) == SIGCHLD) { |
| 141 | if (p->p_xsig) { |
| 142 | if (p->p_sflag & PS_COREDUMP) |
| 143 | ksi->ksi_code = CLD_DUMPED; |
| 144 | else |
| 145 | ksi->ksi_code = CLD_KILLED; |
| 146 | ksi->ksi_status = p->p_xsig; |
| 147 | } else { |
| 148 | ksi->ksi_code = CLD_EXITED; |
| 149 | ksi->ksi_status = p->p_xexit; |
| 150 | } |
| 151 | } else { |
| 152 | ksi->ksi_code = SI_USER; |
| 153 | ksi->ksi_status = p->p_xsig; |
| 154 | } |
| 155 | /* |
| 156 | * We fill those in, even for non-SIGCHLD. |
| 157 | * It's safe to access p->p_cred unlocked here. |
| 158 | */ |
| 159 | ksi->ksi_pid = p->p_pid; |
| 160 | ksi->ksi_uid = kauth_cred_geteuid(p->p_cred); |
| 161 | /* XXX: is this still valid? */ |
| 162 | ksi->ksi_utime = p->p_stats->p_ru.ru_utime.tv_sec; |
| 163 | ksi->ksi_stime = p->p_stats->p_ru.ru_stime.tv_sec; |
| 164 | } |
| 165 | |
| 166 | /* |
| 167 | * exit -- |
| 168 | * Death of process. |
| 169 | */ |
| 170 | int |
| 171 | sys_exit(struct lwp *l, const struct sys_exit_args *uap, register_t *retval) |
| 172 | { |
| 173 | /* { |
| 174 | syscallarg(int) rval; |
| 175 | } */ |
| 176 | struct proc *p = l->l_proc; |
| 177 | |
| 178 | /* Don't call exit1() multiple times in the same process. */ |
| 179 | mutex_enter(p->p_lock); |
| 180 | if (p->p_sflag & PS_WEXIT) { |
| 181 | mutex_exit(p->p_lock); |
| 182 | lwp_exit(l); |
| 183 | } |
| 184 | |
| 185 | /* exit1() will release the mutex. */ |
| 186 | exit1(l, SCARG(uap, rval), 0); |
| 187 | /* NOTREACHED */ |
| 188 | return (0); |
| 189 | } |
| 190 | |
| 191 | /* |
| 192 | * Exit: deallocate address space and other resources, change proc state |
| 193 | * to zombie, and unlink proc from allproc and parent's lists. Save exit |
| 194 | * status and rusage for wait(). Check for child processes and orphan them. |
| 195 | * |
| 196 | * Must be called with p->p_lock held. Does not return. |
| 197 | */ |
| 198 | void |
| 199 | exit1(struct lwp *l, int exitcode, int signo) |
| 200 | { |
| 201 | struct proc *p, *child, *next_child, *old_parent, *new_parent; |
| 202 | struct pgrp *pgrp; |
| 203 | ksiginfo_t ksi; |
| 204 | ksiginfoq_t kq; |
| 205 | int wakeinit; |
| 206 | |
| 207 | p = l->l_proc; |
| 208 | |
| 209 | KASSERT(mutex_owned(p->p_lock)); |
| 210 | KASSERT(p->p_vmspace != NULL); |
| 211 | |
| 212 | if (__predict_false(p == initproc)) { |
| 213 | panic("init died (signal %d, exit %d)" , signo, exitcode); |
| 214 | } |
| 215 | |
| 216 | p->p_sflag |= PS_WEXIT; |
| 217 | |
| 218 | /* |
| 219 | * Force all other LWPs to exit before we do. Only then can we |
| 220 | * begin to tear down the rest of the process state. |
| 221 | */ |
| 222 | if (p->p_nlwps > 1) { |
| 223 | exit_lwps(l); |
| 224 | } |
| 225 | |
| 226 | ksiginfo_queue_init(&kq); |
| 227 | |
| 228 | /* |
| 229 | * If we have been asked to stop on exit, do so now. |
| 230 | */ |
| 231 | if (__predict_false(p->p_sflag & PS_STOPEXIT)) { |
| 232 | KERNEL_UNLOCK_ALL(l, &l->l_biglocks); |
| 233 | sigclearall(p, &contsigmask, &kq); |
| 234 | |
| 235 | if (!mutex_tryenter(proc_lock)) { |
| 236 | mutex_exit(p->p_lock); |
| 237 | mutex_enter(proc_lock); |
| 238 | mutex_enter(p->p_lock); |
| 239 | } |
| 240 | p->p_waited = 0; |
| 241 | p->p_pptr->p_nstopchild++; |
| 242 | p->p_stat = SSTOP; |
| 243 | mutex_exit(proc_lock); |
| 244 | lwp_lock(l); |
| 245 | p->p_nrlwps--; |
| 246 | l->l_stat = LSSTOP; |
| 247 | lwp_unlock(l); |
| 248 | mutex_exit(p->p_lock); |
| 249 | lwp_lock(l); |
| 250 | mi_switch(l); |
| 251 | KERNEL_LOCK(l->l_biglocks, l); |
| 252 | mutex_enter(p->p_lock); |
| 253 | } |
| 254 | |
| 255 | /* |
| 256 | * Bin any remaining signals and mark the process as dying so it will |
| 257 | * not be found for, e.g. signals. |
| 258 | */ |
| 259 | sigfillset(&p->p_sigctx.ps_sigignore); |
| 260 | sigclearall(p, NULL, &kq); |
| 261 | p->p_stat = SDYING; |
| 262 | mutex_exit(p->p_lock); |
| 263 | ksiginfo_queue_drain(&kq); |
| 264 | |
| 265 | /* Destroy any lwpctl info. */ |
| 266 | if (p->p_lwpctl != NULL) |
| 267 | lwp_ctl_exit(); |
| 268 | |
| 269 | /* |
| 270 | * Drain all remaining references that procfs, ptrace and others may |
| 271 | * have on the process. |
| 272 | */ |
| 273 | rw_enter(&p->p_reflock, RW_WRITER); |
| 274 | |
| 275 | DPRINTF(("%s: %d.%d exiting.\n" , __func__, p->p_pid, l->l_lid)); |
| 276 | |
| 277 | timers_free(p, TIMERS_ALL); |
| 278 | #if defined(__HAVE_RAS) |
| 279 | ras_purgeall(); |
| 280 | #endif |
| 281 | |
| 282 | /* |
| 283 | * Close open files, release open-file table and free signal |
| 284 | * actions. This may block! |
| 285 | */ |
| 286 | fd_free(); |
| 287 | cwdfree(p->p_cwdi); |
| 288 | p->p_cwdi = NULL; |
| 289 | doexithooks(p); |
| 290 | sigactsfree(p->p_sigacts); |
| 291 | |
| 292 | /* |
| 293 | * Write out accounting data. |
| 294 | */ |
| 295 | (void)acct_process(l); |
| 296 | |
| 297 | #ifdef KTRACE |
| 298 | /* |
| 299 | * Release trace file. |
| 300 | */ |
| 301 | if (p->p_tracep != NULL) { |
| 302 | mutex_enter(&ktrace_lock); |
| 303 | ktrderef(p); |
| 304 | mutex_exit(&ktrace_lock); |
| 305 | } |
| 306 | #endif |
| 307 | |
| 308 | p->p_xexit = exitcode; |
| 309 | p->p_xsig = signo; |
| 310 | |
| 311 | /* |
| 312 | * If emulation has process exit hook, call it now. |
| 313 | * Set the exit status now so that the exit hook has |
| 314 | * an opportunity to tweak it (COMPAT_LINUX requires |
| 315 | * this for thread group emulation) |
| 316 | */ |
| 317 | if (p->p_emul->e_proc_exit) |
| 318 | (*p->p_emul->e_proc_exit)(p); |
| 319 | |
| 320 | /* |
| 321 | * Free the VM resources we're still holding on to. |
| 322 | * We must do this from a valid thread because doing |
| 323 | * so may block. This frees vmspace, which we don't |
| 324 | * need anymore. The only remaining lwp is the one |
| 325 | * we run at this moment, nothing runs in userland |
| 326 | * anymore. |
| 327 | */ |
| 328 | uvm_proc_exit(p); |
| 329 | |
| 330 | /* |
| 331 | * Stop profiling. |
| 332 | */ |
| 333 | if (__predict_false((p->p_stflag & PST_PROFIL) != 0)) { |
| 334 | mutex_spin_enter(&p->p_stmutex); |
| 335 | stopprofclock(p); |
| 336 | mutex_spin_exit(&p->p_stmutex); |
| 337 | } |
| 338 | |
| 339 | /* |
| 340 | * If parent is waiting for us to exit or exec, PL_PPWAIT is set; we |
| 341 | * wake up the parent early to avoid deadlock. We can do this once |
| 342 | * the VM resources are released. |
| 343 | */ |
| 344 | mutex_enter(proc_lock); |
| 345 | if (p->p_lflag & PL_PPWAIT) { |
| 346 | #if 0 |
| 347 | lwp_t *lp; |
| 348 | |
| 349 | l->l_lwpctl = NULL; /* was on loan from blocked parent */ |
| 350 | p->p_lflag &= ~PL_PPWAIT; |
| 351 | |
| 352 | lp = p->p_vforklwp; |
| 353 | p->p_vforklwp = NULL; |
| 354 | lp->l_pflag &= ~LP_VFORKWAIT; /* XXX */ |
| 355 | cv_broadcast(&lp->l_waitcv); |
| 356 | #else |
| 357 | l->l_lwpctl = NULL; /* was on loan from blocked parent */ |
| 358 | p->p_lflag &= ~PL_PPWAIT; |
| 359 | cv_broadcast(&p->p_pptr->p_waitcv); |
| 360 | #endif |
| 361 | } |
| 362 | |
| 363 | if (SESS_LEADER(p)) { |
| 364 | struct vnode *vprele = NULL, *vprevoke = NULL; |
| 365 | struct session *sp = p->p_session; |
| 366 | struct tty *tp; |
| 367 | |
| 368 | if (sp->s_ttyvp) { |
| 369 | /* |
| 370 | * Controlling process. |
| 371 | * Signal foreground pgrp, |
| 372 | * drain controlling terminal |
| 373 | * and revoke access to controlling terminal. |
| 374 | */ |
| 375 | tp = sp->s_ttyp; |
| 376 | mutex_spin_enter(&tty_lock); |
| 377 | if (tp->t_session == sp) { |
| 378 | /* we can't guarantee the revoke will do this */ |
| 379 | pgrp = tp->t_pgrp; |
| 380 | tp->t_pgrp = NULL; |
| 381 | tp->t_session = NULL; |
| 382 | mutex_spin_exit(&tty_lock); |
| 383 | if (pgrp != NULL) { |
| 384 | pgsignal(pgrp, SIGHUP, 1); |
| 385 | } |
| 386 | mutex_exit(proc_lock); |
| 387 | (void) ttywait(tp); |
| 388 | mutex_enter(proc_lock); |
| 389 | |
| 390 | /* The tty could have been revoked. */ |
| 391 | vprevoke = sp->s_ttyvp; |
| 392 | } else |
| 393 | mutex_spin_exit(&tty_lock); |
| 394 | vprele = sp->s_ttyvp; |
| 395 | sp->s_ttyvp = NULL; |
| 396 | /* |
| 397 | * s_ttyp is not zero'd; we use this to indicate |
| 398 | * that the session once had a controlling terminal. |
| 399 | * (for logging and informational purposes) |
| 400 | */ |
| 401 | } |
| 402 | sp->s_leader = NULL; |
| 403 | |
| 404 | if (vprevoke != NULL || vprele != NULL) { |
| 405 | if (vprevoke != NULL) { |
| 406 | /* Releases proc_lock. */ |
| 407 | proc_sessrele(sp); |
| 408 | VOP_REVOKE(vprevoke, REVOKEALL); |
| 409 | } else |
| 410 | mutex_exit(proc_lock); |
| 411 | if (vprele != NULL) |
| 412 | vrele(vprele); |
| 413 | mutex_enter(proc_lock); |
| 414 | } |
| 415 | } |
| 416 | fixjobc(p, p->p_pgrp, 0); |
| 417 | |
| 418 | /* |
| 419 | * Finalize the last LWP's specificdata, as well as the |
| 420 | * specificdata for the proc itself. |
| 421 | */ |
| 422 | lwp_finispecific(l); |
| 423 | proc_finispecific(p); |
| 424 | |
| 425 | /* |
| 426 | * Notify interested parties of our demise. |
| 427 | */ |
| 428 | KNOTE(&p->p_klist, NOTE_EXIT); |
| 429 | |
| 430 | SDT_PROBE(proc, kernel, , exit, |
| 431 | ((p->p_sflag & PS_COREDUMP) ? CLD_DUMPED : |
| 432 | (p->p_xsig ? CLD_KILLED : CLD_EXITED)), |
| 433 | 0,0,0,0); |
| 434 | |
| 435 | #if PERFCTRS |
| 436 | /* |
| 437 | * Save final PMC information in parent process & clean up. |
| 438 | */ |
| 439 | if (PMC_ENABLED(p)) { |
| 440 | pmc_save_context(p); |
| 441 | pmc_accumulate(p->p_pptr, p); |
| 442 | pmc_process_exit(p); |
| 443 | } |
| 444 | #endif |
| 445 | |
| 446 | /* |
| 447 | * Reset p_opptr pointer of all former children which got |
| 448 | * traced by another process and were reparented. We reset |
| 449 | * it to NULL here; the trace detach code then reparents |
| 450 | * the child to initproc. We only check allproc list, since |
| 451 | * eventual former children on zombproc list won't reference |
| 452 | * p_opptr anymore. |
| 453 | */ |
| 454 | if (__predict_false(p->p_slflag & PSL_CHTRACED)) { |
| 455 | struct proc *q; |
| 456 | PROCLIST_FOREACH(q, &allproc) { |
| 457 | if (q->p_opptr == p) |
| 458 | q->p_opptr = NULL; |
| 459 | } |
| 460 | PROCLIST_FOREACH(q, &zombproc) { |
| 461 | if (q->p_opptr == p) |
| 462 | q->p_opptr = NULL; |
| 463 | } |
| 464 | } |
| 465 | |
| 466 | /* |
| 467 | * Give orphaned children to init(8). |
| 468 | */ |
| 469 | child = LIST_FIRST(&p->p_children); |
| 470 | wakeinit = (child != NULL); |
| 471 | for (; child != NULL; child = next_child) { |
| 472 | next_child = LIST_NEXT(child, p_sibling); |
| 473 | |
| 474 | /* |
| 475 | * Traced processes are killed since their existence |
| 476 | * means someone is screwing up. Since we reset the |
| 477 | * trace flags, the logic in sys_wait4() would not be |
| 478 | * triggered to reparent the process to its |
| 479 | * original parent, so we must do this here. |
| 480 | */ |
| 481 | if (__predict_false(child->p_slflag & PSL_TRACED)) { |
| 482 | mutex_enter(p->p_lock); |
| 483 | child->p_slflag &= |
| 484 | ~(PSL_TRACED|PSL_FSTRACE|PSL_SYSCALL); |
| 485 | mutex_exit(p->p_lock); |
| 486 | if (child->p_opptr != child->p_pptr) { |
| 487 | struct proc *t = child->p_opptr; |
| 488 | proc_reparent(child, t ? t : initproc); |
| 489 | child->p_opptr = NULL; |
| 490 | } else |
| 491 | proc_reparent(child, initproc); |
| 492 | killproc(child, "orphaned traced process" ); |
| 493 | } else |
| 494 | proc_reparent(child, initproc); |
| 495 | } |
| 496 | |
| 497 | /* |
| 498 | * Move proc from allproc to zombproc, it's now nearly ready to be |
| 499 | * collected by parent. |
| 500 | */ |
| 501 | LIST_REMOVE(l, l_list); |
| 502 | LIST_REMOVE(p, p_list); |
| 503 | LIST_INSERT_HEAD(&zombproc, p, p_list); |
| 504 | |
| 505 | /* |
| 506 | * Mark the process as dead. We must do this before we signal |
| 507 | * the parent. |
| 508 | */ |
| 509 | p->p_stat = SDEAD; |
| 510 | |
| 511 | /* Put in front of parent's sibling list for parent to collect it */ |
| 512 | old_parent = p->p_pptr; |
| 513 | old_parent->p_nstopchild++; |
| 514 | if (LIST_FIRST(&old_parent->p_children) != p) { |
| 515 | /* Put child where it can be found quickly */ |
| 516 | LIST_REMOVE(p, p_sibling); |
| 517 | LIST_INSERT_HEAD(&old_parent->p_children, p, p_sibling); |
| 518 | } |
| 519 | |
| 520 | /* |
| 521 | * Notify parent that we're gone. If parent has the P_NOCLDWAIT |
| 522 | * flag set, notify init instead (and hope it will handle |
| 523 | * this situation). |
| 524 | */ |
| 525 | if (old_parent->p_flag & (PK_NOCLDWAIT|PK_CLDSIGIGN)) { |
| 526 | proc_reparent(p, initproc); |
| 527 | wakeinit = 1; |
| 528 | |
| 529 | /* |
| 530 | * If this was the last child of our parent, notify |
| 531 | * parent, so in case he was wait(2)ing, he will |
| 532 | * continue. |
| 533 | */ |
| 534 | if (LIST_FIRST(&old_parent->p_children) == NULL) |
| 535 | cv_broadcast(&old_parent->p_waitcv); |
| 536 | } |
| 537 | |
| 538 | /* Reload parent pointer, since p may have been reparented above */ |
| 539 | new_parent = p->p_pptr; |
| 540 | |
| 541 | if (__predict_false((p->p_slflag & PSL_FSTRACE) == 0 && |
| 542 | p->p_exitsig != 0)) { |
| 543 | exit_psignal(p, new_parent, &ksi); |
| 544 | kpsignal(new_parent, &ksi, NULL); |
| 545 | } |
| 546 | |
| 547 | /* Calculate the final rusage info. */ |
| 548 | calcru(p, &p->p_stats->p_ru.ru_utime, &p->p_stats->p_ru.ru_stime, |
| 549 | NULL, NULL); |
| 550 | |
| 551 | if (wakeinit) |
| 552 | cv_broadcast(&initproc->p_waitcv); |
| 553 | |
| 554 | callout_destroy(&l->l_timeout_ch); |
| 555 | |
| 556 | /* |
| 557 | * Release any PCU resources before becoming a zombie. |
| 558 | */ |
| 559 | pcu_discard_all(l); |
| 560 | |
| 561 | mutex_enter(p->p_lock); |
| 562 | /* Free the linux lwp id */ |
| 563 | if ((l->l_pflag & LP_PIDLID) != 0 && l->l_lid != p->p_pid) |
| 564 | proc_free_pid(l->l_lid); |
| 565 | lwp_drainrefs(l); |
| 566 | lwp_lock(l); |
| 567 | l->l_prflag &= ~LPR_DETACHED; |
| 568 | l->l_stat = LSZOMB; |
| 569 | lwp_unlock(l); |
| 570 | KASSERT(curlwp == l); |
| 571 | KASSERT(p->p_nrlwps == 1); |
| 572 | KASSERT(p->p_nlwps == 1); |
| 573 | p->p_stat = SZOMB; |
| 574 | p->p_nrlwps--; |
| 575 | p->p_nzlwps++; |
| 576 | p->p_ndlwps = 0; |
| 577 | mutex_exit(p->p_lock); |
| 578 | |
| 579 | /* |
| 580 | * Signal the parent to collect us, and drop the proclist lock. |
| 581 | * Drop debugger/procfs lock; no new references can be gained. |
| 582 | */ |
| 583 | cv_broadcast(&p->p_pptr->p_waitcv); |
| 584 | rw_exit(&p->p_reflock); |
| 585 | mutex_exit(proc_lock); |
| 586 | |
| 587 | /* Verify that we hold no locks other than the kernel lock. */ |
| 588 | LOCKDEBUG_BARRIER(&kernel_lock, 0); |
| 589 | |
| 590 | /* |
| 591 | * NOTE: WE ARE NO LONGER ALLOWED TO SLEEP! |
| 592 | */ |
| 593 | |
| 594 | /* |
| 595 | * Give machine-dependent code a chance to free any MD LWP |
| 596 | * resources. This must be done before uvm_lwp_exit(), in |
| 597 | * case these resources are in the PCB. |
| 598 | */ |
| 599 | cpu_lwp_free(l, 1); |
| 600 | |
| 601 | pmap_deactivate(l); |
| 602 | |
| 603 | /* This process no longer needs to hold the kernel lock. */ |
| 604 | #ifdef notyet |
| 605 | /* XXXSMP hold in lwp_userret() */ |
| 606 | KERNEL_UNLOCK_LAST(l); |
| 607 | #else |
| 608 | KERNEL_UNLOCK_ALL(l, NULL); |
| 609 | #endif |
| 610 | |
| 611 | lwp_exit_switchaway(l); |
| 612 | } |
| 613 | |
| 614 | void |
| 615 | exit_lwps(struct lwp *l) |
| 616 | { |
| 617 | proc_t *p = l->l_proc; |
| 618 | lwp_t *l2; |
| 619 | int nlocks; |
| 620 | |
| 621 | KERNEL_UNLOCK_ALL(l, &nlocks); |
| 622 | retry: |
| 623 | KASSERT(mutex_owned(p->p_lock)); |
| 624 | |
| 625 | /* |
| 626 | * Interrupt LWPs in interruptable sleep, unsuspend suspended |
| 627 | * LWPs and then wait for everyone else to finish. |
| 628 | */ |
| 629 | LIST_FOREACH(l2, &p->p_lwps, l_sibling) { |
| 630 | if (l2 == l) |
| 631 | continue; |
| 632 | lwp_lock(l2); |
| 633 | l2->l_flag |= LW_WEXIT; |
| 634 | if ((l2->l_stat == LSSLEEP && (l2->l_flag & LW_SINTR)) || |
| 635 | l2->l_stat == LSSUSPENDED || l2->l_stat == LSSTOP) { |
| 636 | /* setrunnable() will release the lock. */ |
| 637 | setrunnable(l2); |
| 638 | continue; |
| 639 | } |
| 640 | lwp_unlock(l2); |
| 641 | } |
| 642 | |
| 643 | /* |
| 644 | * Wait for every LWP to exit. Note: LWPs can get suspended/slept |
| 645 | * behind us or there may even be new LWPs created. Therefore, a |
| 646 | * full retry is required on error. |
| 647 | */ |
| 648 | while (p->p_nlwps > 1) { |
| 649 | if (lwp_wait(l, 0, NULL, true)) { |
| 650 | goto retry; |
| 651 | } |
| 652 | } |
| 653 | |
| 654 | KERNEL_LOCK(nlocks, l); |
| 655 | KASSERT(p->p_nlwps == 1); |
| 656 | } |
| 657 | |
| 658 | int |
| 659 | do_sys_waitid(idtype_t idtype, id_t id, int *pid, int *status, int options, |
| 660 | struct wrusage *wru, siginfo_t *si) |
| 661 | { |
| 662 | proc_t *child; |
| 663 | int error; |
| 664 | |
| 665 | |
| 666 | if (wru != NULL) |
| 667 | memset(wru, 0, sizeof(*wru)); |
| 668 | if (si != NULL) |
| 669 | memset(si, 0, sizeof(*si)); |
| 670 | |
| 671 | mutex_enter(proc_lock); |
| 672 | error = find_stopped_child(curproc, idtype, id, options, &child, |
| 673 | wru, si); |
| 674 | if (child == NULL) { |
| 675 | mutex_exit(proc_lock); |
| 676 | *pid = 0; |
| 677 | return error; |
| 678 | } |
| 679 | *pid = child->p_pid; |
| 680 | |
| 681 | if (child->p_stat == SZOMB) { |
| 682 | /* Child is exiting */ |
| 683 | *status = P_WAITSTATUS(child); |
| 684 | /* proc_free() will release the proc_lock. */ |
| 685 | if (options & WNOWAIT) { |
| 686 | mutex_exit(proc_lock); |
| 687 | } else { |
| 688 | proc_free(child, wru); |
| 689 | } |
| 690 | } else { |
| 691 | /* Don't mark SIGCONT if we are being stopped */ |
| 692 | *status = (child->p_xsig == SIGCONT && child->p_stat != SSTOP) ? |
| 693 | W_CONTCODE() : W_STOPCODE(child->p_xsig); |
| 694 | mutex_exit(proc_lock); |
| 695 | } |
| 696 | return 0; |
| 697 | } |
| 698 | |
| 699 | int |
| 700 | do_sys_wait(int *pid, int *status, int options, struct rusage *ru) |
| 701 | { |
| 702 | idtype_t idtype; |
| 703 | id_t id; |
| 704 | int ret; |
| 705 | struct wrusage wru; |
| 706 | |
| 707 | /* |
| 708 | * Translate the special pid values into the (idtype, pid) |
| 709 | * pair for wait6. The WAIT_MYPGRP case is handled by |
| 710 | * find_stopped_child() on its own. |
| 711 | */ |
| 712 | if (*pid == WAIT_ANY) { |
| 713 | idtype = P_ALL; |
| 714 | id = 0; |
| 715 | } else if (*pid < 0) { |
| 716 | idtype = P_PGID; |
| 717 | id = (id_t)-*pid; |
| 718 | } else { |
| 719 | idtype = P_PID; |
| 720 | id = (id_t)*pid; |
| 721 | } |
| 722 | options |= WEXITED | WTRAPPED; |
| 723 | ret = do_sys_waitid(idtype, id, pid, status, options, ru ? &wru : NULL, |
| 724 | NULL); |
| 725 | if (ru) |
| 726 | *ru = wru.wru_self; |
| 727 | return ret; |
| 728 | } |
| 729 | |
| 730 | int |
| 731 | sys___wait450(struct lwp *l, const struct sys___wait450_args *uap, |
| 732 | register_t *retval) |
| 733 | { |
| 734 | /* { |
| 735 | syscallarg(int) pid; |
| 736 | syscallarg(int *) status; |
| 737 | syscallarg(int) options; |
| 738 | syscallarg(struct rusage *) rusage; |
| 739 | } */ |
| 740 | int error, status, pid = SCARG(uap, pid); |
| 741 | struct rusage ru; |
| 742 | |
| 743 | error = do_sys_wait(&pid, &status, SCARG(uap, options), |
| 744 | SCARG(uap, rusage) != NULL ? &ru : NULL); |
| 745 | |
| 746 | retval[0] = pid; |
| 747 | if (pid == 0) { |
| 748 | return error; |
| 749 | } |
| 750 | if (SCARG(uap, status)) { |
| 751 | error = copyout(&status, SCARG(uap, status), sizeof(status)); |
| 752 | } |
| 753 | if (SCARG(uap, rusage) && error == 0) { |
| 754 | error = copyout(&ru, SCARG(uap, rusage), sizeof(ru)); |
| 755 | } |
| 756 | return error; |
| 757 | } |
| 758 | |
| 759 | int |
| 760 | sys_wait6(struct lwp *l, const struct sys_wait6_args *uap, register_t *retval) |
| 761 | { |
| 762 | /* { |
| 763 | syscallarg(idtype_t) idtype; |
| 764 | syscallarg(id_t) id; |
| 765 | syscallarg(int *) status; |
| 766 | syscallarg(int) options; |
| 767 | syscallarg(struct wrusage *) wru; |
| 768 | syscallarg(siginfo_t *) si; |
| 769 | } */ |
| 770 | struct wrusage wru, *wrup; |
| 771 | siginfo_t si, *sip; |
| 772 | idtype_t idtype; |
| 773 | int pid; |
| 774 | id_t id; |
| 775 | int error, status; |
| 776 | |
| 777 | idtype = SCARG(uap, idtype); |
| 778 | id = SCARG(uap, id); |
| 779 | |
| 780 | if (SCARG(uap, wru) != NULL) |
| 781 | wrup = &wru; |
| 782 | else |
| 783 | wrup = NULL; |
| 784 | |
| 785 | if (SCARG(uap, info) != NULL) |
| 786 | sip = &si; |
| 787 | else |
| 788 | sip = NULL; |
| 789 | |
| 790 | /* |
| 791 | * We expect all callers of wait6() to know about WEXITED and |
| 792 | * WTRAPPED. |
| 793 | */ |
| 794 | error = do_sys_waitid(idtype, id, &pid, &status, SCARG(uap, options), |
| 795 | wrup, sip); |
| 796 | |
| 797 | retval[0] = pid; /* tell userland who it was */ |
| 798 | |
| 799 | #if 0 |
| 800 | /* |
| 801 | * should we copyout if there was no process, hence no useful data? |
| 802 | * We don't for an old sytle wait4() (etc) but I believe |
| 803 | * FreeBSD does for wait6(), so a tossup... Go with FreeBSD for now. |
| 804 | */ |
| 805 | if (pid == 0) |
| 806 | return error; |
| 807 | #endif |
| 808 | |
| 809 | if (SCARG(uap, status) != NULL && error == 0) |
| 810 | error = copyout(&status, SCARG(uap, status), sizeof(status)); |
| 811 | if (SCARG(uap, wru) != NULL && error == 0) |
| 812 | error = copyout(&wru, SCARG(uap, wru), sizeof(wru)); |
| 813 | if (SCARG(uap, info) != NULL && error == 0) |
| 814 | error = copyout(&si, SCARG(uap, info), sizeof(si)); |
| 815 | return error; |
| 816 | } |
| 817 | |
| 818 | |
| 819 | /* |
| 820 | * Find a process that matches the provided criteria, and fill siginfo |
| 821 | * and resources if found. |
| 822 | * Returns: |
| 823 | * -1: Not found, abort early |
| 824 | * 0: Not matched |
| 825 | * 1: Matched, there might be more matches |
| 826 | * 2: This is the only match |
| 827 | */ |
| 828 | static int |
| 829 | match_process(const struct proc *pp, struct proc **q, idtype_t idtype, id_t id, |
| 830 | int options, struct wrusage *wrusage, siginfo_t *siginfo) |
| 831 | { |
| 832 | struct rusage *rup; |
| 833 | struct proc *p = *q; |
| 834 | int rv = 1; |
| 835 | |
| 836 | mutex_enter(p->p_lock); |
| 837 | switch (idtype) { |
| 838 | case P_ALL: |
| 839 | break; |
| 840 | case P_PID: |
| 841 | if (p->p_pid != (pid_t)id) { |
| 842 | mutex_exit(p->p_lock); |
| 843 | p = *q = proc_find_raw((pid_t)id); |
| 844 | if (p == NULL || p->p_stat == SIDL || p->p_pptr != pp) { |
| 845 | *q = NULL; |
| 846 | return -1; |
| 847 | } |
| 848 | mutex_enter(p->p_lock); |
| 849 | } |
| 850 | rv++; |
| 851 | break; |
| 852 | case P_PGID: |
| 853 | if (p->p_pgid != (pid_t)id) |
| 854 | goto out; |
| 855 | break; |
| 856 | case P_SID: |
| 857 | if (p->p_session->s_sid != (pid_t)id) |
| 858 | goto out; |
| 859 | break; |
| 860 | case P_UID: |
| 861 | if (kauth_cred_geteuid(p->p_cred) != (uid_t)id) |
| 862 | goto out; |
| 863 | break; |
| 864 | case P_GID: |
| 865 | if (kauth_cred_getegid(p->p_cred) != (gid_t)id) |
| 866 | goto out; |
| 867 | break; |
| 868 | case P_CID: |
| 869 | case P_PSETID: |
| 870 | case P_CPUID: |
| 871 | /* XXX: Implement me */ |
| 872 | default: |
| 873 | out: |
| 874 | mutex_exit(p->p_lock); |
| 875 | return 0; |
| 876 | } |
| 877 | |
| 878 | if ((options & WEXITED) == 0 && p->p_stat == SZOMB) |
| 879 | goto out; |
| 880 | |
| 881 | if (siginfo != NULL) { |
| 882 | siginfo->si_errno = 0; |
| 883 | |
| 884 | /* |
| 885 | * SUSv4 requires that the si_signo value is always |
| 886 | * SIGCHLD. Obey it despite the rfork(2) interface |
| 887 | * allows to request other signal for child exit |
| 888 | * notification. |
| 889 | */ |
| 890 | siginfo->si_signo = SIGCHLD; |
| 891 | |
| 892 | /* |
| 893 | * This is still a rough estimate. We will fix the |
| 894 | * cases TRAPPED, STOPPED, and CONTINUED later. |
| 895 | */ |
| 896 | if (p->p_sflag & PS_COREDUMP) { |
| 897 | siginfo->si_code = CLD_DUMPED; |
| 898 | siginfo->si_status = p->p_xsig; |
| 899 | } else if (p->p_xsig) { |
| 900 | siginfo->si_code = CLD_KILLED; |
| 901 | siginfo->si_status = p->p_xsig; |
| 902 | } else { |
| 903 | siginfo->si_code = CLD_EXITED; |
| 904 | siginfo->si_status = p->p_xexit; |
| 905 | } |
| 906 | |
| 907 | siginfo->si_pid = p->p_pid; |
| 908 | siginfo->si_uid = kauth_cred_geteuid(p->p_cred); |
| 909 | siginfo->si_utime = p->p_stats->p_ru.ru_utime.tv_sec; |
| 910 | siginfo->si_stime = p->p_stats->p_ru.ru_stime.tv_sec; |
| 911 | } |
| 912 | |
| 913 | /* |
| 914 | * There should be no reason to limit resources usage info to |
| 915 | * exited processes only. A snapshot about any resources used |
| 916 | * by a stopped process may be exactly what is needed. |
| 917 | */ |
| 918 | if (wrusage != NULL) { |
| 919 | rup = &wrusage->wru_self; |
| 920 | *rup = p->p_stats->p_ru; |
| 921 | calcru(p, &rup->ru_utime, &rup->ru_stime, NULL, NULL); |
| 922 | |
| 923 | rup = &wrusage->wru_children; |
| 924 | *rup = p->p_stats->p_cru; |
| 925 | calcru(p, &rup->ru_utime, &rup->ru_stime, NULL, NULL); |
| 926 | } |
| 927 | |
| 928 | mutex_exit(p->p_lock); |
| 929 | return rv; |
| 930 | } |
| 931 | |
| 932 | /* |
| 933 | * Determine if there are existing processes being debugged |
| 934 | * that used to be (and sometime later will be again) children |
| 935 | * of a specific parent (while matching wait criteria) |
| 936 | */ |
| 937 | static bool |
| 938 | debugged_child_exists(idtype_t idtype, id_t id, int options, siginfo_t *si, |
| 939 | const struct proc *parent) |
| 940 | { |
| 941 | struct proc *pp; |
| 942 | |
| 943 | /* |
| 944 | * If we are searching for a specific pid, we can optimise a little |
| 945 | */ |
| 946 | if (idtype == P_PID) { |
| 947 | /* |
| 948 | * Check the specific process to see if its real parent is us |
| 949 | */ |
| 950 | pp = proc_find_raw((pid_t)id); |
| 951 | if (pp != NULL && pp->p_stat != SIDL && pp->p_opptr == parent) { |
| 952 | /* |
| 953 | * using P_ALL here avoids match_process() doing the |
| 954 | * same work that we just did, but incorrectly for |
| 955 | * this scenario. |
| 956 | */ |
| 957 | if (match_process(parent, &pp, P_ALL, id, options, |
| 958 | NULL, si)) |
| 959 | return true; |
| 960 | } |
| 961 | return false; |
| 962 | } |
| 963 | |
| 964 | /* |
| 965 | * For the hard cases, just look everywhere to see if some |
| 966 | * stolen (reparented) process is really our lost child. |
| 967 | * Then check if that process could satisfy the wait conditions. |
| 968 | */ |
| 969 | |
| 970 | /* |
| 971 | * XXX inefficient, but hopefully fairly rare. |
| 972 | * XXX should really use a list of reparented processes. |
| 973 | */ |
| 974 | PROCLIST_FOREACH(pp, &allproc) { |
| 975 | if (pp->p_stat == SIDL) /* XXX impossible ?? */ |
| 976 | continue; |
| 977 | if (pp->p_opptr == parent && |
| 978 | match_process(parent, &pp, idtype, id, options, NULL, si)) |
| 979 | return true; |
| 980 | } |
| 981 | PROCLIST_FOREACH(pp, &zombproc) { |
| 982 | if (pp->p_stat == SIDL) /* XXX impossible ?? */ |
| 983 | continue; |
| 984 | if (pp->p_opptr == parent && |
| 985 | match_process(parent, &pp, idtype, id, options, NULL, si)) |
| 986 | return true; |
| 987 | } |
| 988 | |
| 989 | return false; |
| 990 | } |
| 991 | |
| 992 | /* |
| 993 | * Scan list of child processes for a child process that has stopped or |
| 994 | * exited. Used by sys_wait4 and 'compat' equivalents. |
| 995 | * |
| 996 | * Must be called with the proc_lock held, and may release while waiting. |
| 997 | */ |
| 998 | static int |
| 999 | find_stopped_child(struct proc *parent, idtype_t idtype, id_t id, int options, |
| 1000 | struct proc **child_p, struct wrusage *wru, siginfo_t *si) |
| 1001 | { |
| 1002 | struct proc *child, *dead; |
| 1003 | int error; |
| 1004 | |
| 1005 | KASSERT(mutex_owned(proc_lock)); |
| 1006 | |
| 1007 | if (options & ~WALLOPTS) { |
| 1008 | *child_p = NULL; |
| 1009 | return EINVAL; |
| 1010 | } |
| 1011 | |
| 1012 | if ((options & WSELECTOPTS) == 0) { |
| 1013 | /* |
| 1014 | * We will be unable to find any matching processes, |
| 1015 | * because there are no known events to look for. |
| 1016 | * Prefer to return error instead of blocking |
| 1017 | * indefinitely. |
| 1018 | */ |
| 1019 | *child_p = NULL; |
| 1020 | return EINVAL; |
| 1021 | } |
| 1022 | |
| 1023 | if ((pid_t)id == WAIT_MYPGRP && (idtype == P_PID || idtype == P_PGID)) { |
| 1024 | mutex_enter(parent->p_lock); |
| 1025 | id = (id_t)parent->p_pgid; |
| 1026 | mutex_exit(parent->p_lock); |
| 1027 | idtype = P_PGID; |
| 1028 | } |
| 1029 | |
| 1030 | for (;;) { |
| 1031 | error = ECHILD; |
| 1032 | dead = NULL; |
| 1033 | |
| 1034 | LIST_FOREACH(child, &parent->p_children, p_sibling) { |
| 1035 | int rv = match_process(parent, &child, idtype, id, |
| 1036 | options, wru, si); |
| 1037 | if (rv == -1) |
| 1038 | break; |
| 1039 | if (rv == 0) |
| 1040 | continue; |
| 1041 | |
| 1042 | /* |
| 1043 | * Wait for processes with p_exitsig != SIGCHLD |
| 1044 | * processes only if WALTSIG is set; wait for |
| 1045 | * processes with p_exitsig == SIGCHLD only |
| 1046 | * if WALTSIG is clear. |
| 1047 | */ |
| 1048 | if (((options & WALLSIG) == 0) && |
| 1049 | (options & WALTSIG ? child->p_exitsig == SIGCHLD |
| 1050 | : P_EXITSIG(child) != SIGCHLD)){ |
| 1051 | if (rv == 2) { |
| 1052 | child = NULL; |
| 1053 | break; |
| 1054 | } |
| 1055 | continue; |
| 1056 | } |
| 1057 | |
| 1058 | error = 0; |
| 1059 | if ((options & WNOZOMBIE) == 0) { |
| 1060 | if (child->p_stat == SZOMB) |
| 1061 | break; |
| 1062 | if (child->p_stat == SDEAD) { |
| 1063 | /* |
| 1064 | * We may occasionally arrive here |
| 1065 | * after receiving a signal, but |
| 1066 | * immediately before the child |
| 1067 | * process is zombified. The wait |
| 1068 | * will be short, so avoid returning |
| 1069 | * to userspace. |
| 1070 | */ |
| 1071 | dead = child; |
| 1072 | } |
| 1073 | } |
| 1074 | |
| 1075 | if ((options & WCONTINUED) != 0 && |
| 1076 | child->p_xsig == SIGCONT && |
| 1077 | (child->p_sflag & PS_CONTINUED)) { |
| 1078 | if ((options & WNOWAIT) == 0) { |
| 1079 | child->p_sflag &= ~PS_CONTINUED; |
| 1080 | child->p_waited = 1; |
| 1081 | parent->p_nstopchild--; |
| 1082 | } |
| 1083 | if (si) { |
| 1084 | si->si_status = child->p_xsig; |
| 1085 | si->si_code = CLD_CONTINUED; |
| 1086 | } |
| 1087 | break; |
| 1088 | } |
| 1089 | |
| 1090 | if ((options & (WTRAPPED|WSTOPPED)) != 0 && |
| 1091 | child->p_stat == SSTOP && |
| 1092 | child->p_waited == 0 && |
| 1093 | ((child->p_slflag & PSL_TRACED) || |
| 1094 | options & (WUNTRACED|WSTOPPED))) { |
| 1095 | if ((options & WNOWAIT) == 0) { |
| 1096 | child->p_waited = 1; |
| 1097 | parent->p_nstopchild--; |
| 1098 | } |
| 1099 | if (si) { |
| 1100 | si->si_status = child->p_xsig; |
| 1101 | si->si_code = |
| 1102 | (child->p_slflag & PSL_TRACED) ? |
| 1103 | CLD_TRAPPED : CLD_STOPPED; |
| 1104 | } |
| 1105 | break; |
| 1106 | } |
| 1107 | if (parent->p_nstopchild == 0 || rv == 2) { |
| 1108 | child = NULL; |
| 1109 | break; |
| 1110 | } |
| 1111 | } |
| 1112 | |
| 1113 | /* |
| 1114 | * If we found nothing, but we are the bereaved parent |
| 1115 | * of a stolen child, look and see if that child (or |
| 1116 | * one of them) meets our search criteria. If so, then |
| 1117 | * we cannot succeed, but we can hang (wait...), |
| 1118 | * or if WNOHANG, return 0 instead of ECHILD |
| 1119 | */ |
| 1120 | if (child == NULL && error == ECHILD && |
| 1121 | (parent->p_slflag & PSL_CHTRACED) && |
| 1122 | debugged_child_exists(idtype, id, options, si, parent)) |
| 1123 | error = 0; |
| 1124 | |
| 1125 | if (child != NULL || error != 0 || |
| 1126 | ((options & WNOHANG) != 0 && dead == NULL)) { |
| 1127 | *child_p = child; |
| 1128 | return error; |
| 1129 | } |
| 1130 | |
| 1131 | /* |
| 1132 | * Wait for another child process to stop. |
| 1133 | */ |
| 1134 | error = cv_wait_sig(&parent->p_waitcv, proc_lock); |
| 1135 | |
| 1136 | if (error != 0) { |
| 1137 | *child_p = NULL; |
| 1138 | return error; |
| 1139 | } |
| 1140 | } |
| 1141 | } |
| 1142 | |
| 1143 | /* |
| 1144 | * Free a process after parent has taken all the state info. Must be called |
| 1145 | * with the proclist lock held, and will release before returning. |
| 1146 | * |
| 1147 | * *ru is returned to the caller, and must be freed by the caller. |
| 1148 | */ |
| 1149 | static void |
| 1150 | proc_free(struct proc *p, struct wrusage *wru) |
| 1151 | { |
| 1152 | struct proc *parent = p->p_pptr; |
| 1153 | struct lwp *l; |
| 1154 | ksiginfo_t ksi; |
| 1155 | kauth_cred_t cred1, cred2; |
| 1156 | uid_t uid; |
| 1157 | |
| 1158 | KASSERT(mutex_owned(proc_lock)); |
| 1159 | KASSERT(p->p_nlwps == 1); |
| 1160 | KASSERT(p->p_nzlwps == 1); |
| 1161 | KASSERT(p->p_nrlwps == 0); |
| 1162 | KASSERT(p->p_stat == SZOMB); |
| 1163 | |
| 1164 | /* |
| 1165 | * If we got the child via ptrace(2) or procfs, and |
| 1166 | * the parent is different (meaning the process was |
| 1167 | * attached, rather than run as a child), then we need |
| 1168 | * to give it back to the old parent, and send the |
| 1169 | * parent the exit signal. The rest of the cleanup |
| 1170 | * will be done when the old parent waits on the child. |
| 1171 | */ |
| 1172 | if ((p->p_slflag & PSL_TRACED) != 0 && p->p_opptr != parent) { |
| 1173 | mutex_enter(p->p_lock); |
| 1174 | p->p_slflag &= ~(PSL_TRACED|PSL_FSTRACE|PSL_SYSCALL); |
| 1175 | mutex_exit(p->p_lock); |
| 1176 | parent = (p->p_opptr == NULL) ? initproc : p->p_opptr; |
| 1177 | proc_reparent(p, parent); |
| 1178 | p->p_opptr = NULL; |
| 1179 | if (p->p_exitsig != 0) { |
| 1180 | exit_psignal(p, parent, &ksi); |
| 1181 | kpsignal(parent, &ksi, NULL); |
| 1182 | } |
| 1183 | cv_broadcast(&parent->p_waitcv); |
| 1184 | mutex_exit(proc_lock); |
| 1185 | return; |
| 1186 | } |
| 1187 | |
| 1188 | sched_proc_exit(parent, p); |
| 1189 | |
| 1190 | /* |
| 1191 | * Add child times of exiting process onto its own times. |
| 1192 | * This cannot be done any earlier else it might get done twice. |
| 1193 | */ |
| 1194 | l = LIST_FIRST(&p->p_lwps); |
| 1195 | p->p_stats->p_ru.ru_nvcsw += (l->l_ncsw - l->l_nivcsw); |
| 1196 | p->p_stats->p_ru.ru_nivcsw += l->l_nivcsw; |
| 1197 | ruadd(&p->p_stats->p_ru, &l->l_ru); |
| 1198 | ruadd(&p->p_stats->p_ru, &p->p_stats->p_cru); |
| 1199 | ruadd(&parent->p_stats->p_cru, &p->p_stats->p_ru); |
| 1200 | if (wru != NULL) { |
| 1201 | wru->wru_self = p->p_stats->p_ru; |
| 1202 | wru->wru_children = p->p_stats->p_cru; |
| 1203 | } |
| 1204 | p->p_xsig = 0; |
| 1205 | p->p_xexit = 0; |
| 1206 | |
| 1207 | /* |
| 1208 | * At this point we are going to start freeing the final resources. |
| 1209 | * If anyone tries to access the proc structure after here they will |
| 1210 | * get a shock - bits are missing. Attempt to make it hard! We |
| 1211 | * don't bother with any further locking past this point. |
| 1212 | */ |
| 1213 | p->p_stat = SIDL; /* not even a zombie any more */ |
| 1214 | LIST_REMOVE(p, p_list); /* off zombproc */ |
| 1215 | parent->p_nstopchild--; |
| 1216 | LIST_REMOVE(p, p_sibling); |
| 1217 | |
| 1218 | /* |
| 1219 | * Let pid be reallocated. |
| 1220 | */ |
| 1221 | proc_free_pid(p->p_pid); |
| 1222 | |
| 1223 | /* |
| 1224 | * Unlink process from its process group. |
| 1225 | * Releases the proc_lock. |
| 1226 | */ |
| 1227 | proc_leavepgrp(p); |
| 1228 | |
| 1229 | /* |
| 1230 | * Delay release until after lwp_free. |
| 1231 | */ |
| 1232 | cred2 = l->l_cred; |
| 1233 | |
| 1234 | /* |
| 1235 | * Free the last LWP's resources. |
| 1236 | * |
| 1237 | * lwp_free ensures the LWP is no longer running on another CPU. |
| 1238 | */ |
| 1239 | lwp_free(l, false, true); |
| 1240 | |
| 1241 | /* |
| 1242 | * Now no one except us can reach the process p. |
| 1243 | */ |
| 1244 | |
| 1245 | /* |
| 1246 | * Decrement the count of procs running with this uid. |
| 1247 | */ |
| 1248 | cred1 = p->p_cred; |
| 1249 | uid = kauth_cred_getuid(cred1); |
| 1250 | (void)chgproccnt(uid, -1); |
| 1251 | |
| 1252 | /* |
| 1253 | * Release substructures. |
| 1254 | */ |
| 1255 | |
| 1256 | lim_free(p->p_limit); |
| 1257 | pstatsfree(p->p_stats); |
| 1258 | kauth_cred_free(cred1); |
| 1259 | kauth_cred_free(cred2); |
| 1260 | |
| 1261 | /* |
| 1262 | * Release reference to text vnode |
| 1263 | */ |
| 1264 | if (p->p_textvp) |
| 1265 | vrele(p->p_textvp); |
| 1266 | |
| 1267 | mutex_destroy(&p->p_auxlock); |
| 1268 | mutex_obj_free(p->p_lock); |
| 1269 | mutex_destroy(&p->p_stmutex); |
| 1270 | cv_destroy(&p->p_waitcv); |
| 1271 | cv_destroy(&p->p_lwpcv); |
| 1272 | rw_destroy(&p->p_reflock); |
| 1273 | |
| 1274 | proc_free_mem(p); |
| 1275 | } |
| 1276 | |
| 1277 | /* |
| 1278 | * Change the parent of a process for tracing purposes. |
| 1279 | */ |
| 1280 | void |
| 1281 | proc_changeparent(struct proc *t, struct proc *p) |
| 1282 | { |
| 1283 | SET(t->p_slflag, PSL_TRACED); |
| 1284 | t->p_opptr = t->p_pptr; |
| 1285 | if (t->p_pptr == p) |
| 1286 | return; |
| 1287 | struct proc *parent = t->p_pptr; |
| 1288 | |
| 1289 | if (parent->p_lock < t->p_lock) { |
| 1290 | if (!mutex_tryenter(parent->p_lock)) { |
| 1291 | mutex_exit(t->p_lock); |
| 1292 | mutex_enter(parent->p_lock); |
| 1293 | mutex_enter(t->p_lock); |
| 1294 | } |
| 1295 | } else if (parent->p_lock > t->p_lock) { |
| 1296 | mutex_enter(parent->p_lock); |
| 1297 | } |
| 1298 | parent->p_slflag |= PSL_CHTRACED; |
| 1299 | proc_reparent(t, p); |
| 1300 | if (parent->p_lock != t->p_lock) |
| 1301 | mutex_exit(parent->p_lock); |
| 1302 | } |
| 1303 | |
| 1304 | /* |
| 1305 | * make process 'parent' the new parent of process 'child'. |
| 1306 | * |
| 1307 | * Must be called with proc_lock held. |
| 1308 | */ |
| 1309 | void |
| 1310 | proc_reparent(struct proc *child, struct proc *parent) |
| 1311 | { |
| 1312 | |
| 1313 | KASSERT(mutex_owned(proc_lock)); |
| 1314 | |
| 1315 | if (child->p_pptr == parent) |
| 1316 | return; |
| 1317 | |
| 1318 | if (child->p_stat == SZOMB || child->p_stat == SDEAD || |
| 1319 | (child->p_stat == SSTOP && !child->p_waited)) { |
| 1320 | child->p_pptr->p_nstopchild--; |
| 1321 | parent->p_nstopchild++; |
| 1322 | } |
| 1323 | if (parent == initproc) { |
| 1324 | child->p_exitsig = SIGCHLD; |
| 1325 | child->p_ppid = parent->p_pid; |
| 1326 | } |
| 1327 | |
| 1328 | LIST_REMOVE(child, p_sibling); |
| 1329 | LIST_INSERT_HEAD(&parent->p_children, child, p_sibling); |
| 1330 | child->p_pptr = parent; |
| 1331 | } |
| 1332 | |