| 1 | /* |
| 2 | * Copyright (c) 1982, 1986, 1989, 1991, 1993 |
| 3 | * The Regents of the University of California. All rights reserved. |
| 4 | * (c) UNIX System Laboratories, Inc. |
| 5 | * All or some portions of this file are derived from material licensed |
| 6 | * to the University of California by American Telephone and Telegraph |
| 7 | * Co. or Unix System Laboratories, Inc. and are reproduced herein with |
| 8 | * the permission of UNIX System Laboratories, Inc. |
| 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 | * 3. All advertising materials mentioning features or use of this software |
| 19 | * must display the following acknowledgement: |
| 20 | * This product includes software developed by the University of |
| 21 | * California, Berkeley and its contributors. |
| 22 | * 4. Neither the name of the University nor the names of its contributors |
| 23 | * may be used to endorse or promote products derived from this software |
| 24 | * without specific prior written permission. |
| 25 | * |
| 26 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 27 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 28 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 29 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 30 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 31 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 32 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 33 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 34 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 35 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 36 | * SUCH DAMAGE. |
| 37 | * |
| 38 | * @(#)kern_sig.c 8.7 (Berkeley) 4/18/94 |
| 39 | * $FreeBSD: src/sys/kern/kern_sig.c,v 1.72.2.17 2003/05/16 16:34:34 obrien Exp $ |
| 40 | * $DragonFly: src/sys/kern/kern_sig.c,v 1.27 2004/03/01 06:33:17 dillon Exp $ |
| 41 | */ |
| 42 | |
| 43 | #include "opt_ktrace.h" |
| 44 | |
| 45 | #include <sys/param.h> |
| 46 | #include <sys/systm.h> |
| 47 | #include <sys/kernel.h> |
| 48 | #include <sys/sysproto.h> |
| 49 | #include <sys/signalvar.h> |
| 50 | #include <sys/resourcevar.h> |
| 51 | #include <sys/vnode.h> |
| 52 | #include <sys/event.h> |
| 53 | #include <sys/proc.h> |
| 54 | #include <sys/namei.h> |
| 55 | #include <sys/pioctl.h> |
| 56 | #include <sys/systm.h> |
| 57 | #include <sys/acct.h> |
| 58 | #include <sys/fcntl.h> |
| 59 | #include <sys/wait.h> |
| 60 | #include <sys/ktrace.h> |
| 61 | #include <sys/syslog.h> |
| 62 | #include <sys/stat.h> |
| 63 | #include <sys/sysent.h> |
| 64 | #include <sys/sysctl.h> |
| 65 | #include <sys/malloc.h> |
| 66 | #include <sys/unistd.h> |
| 67 | #include <sys/kern_syscall.h> |
| 68 | |
| 69 | |
| 70 | #include <machine/ipl.h> |
| 71 | #include <machine/cpu.h> |
| 72 | #include <machine/smp.h> |
| 73 | |
| 74 | static int coredump (struct proc *); |
| 75 | static char *expand_name (const char *, uid_t, pid_t); |
| 76 | static int killpg (int sig, int pgid, int all); |
| 77 | static int sig_ffs (sigset_t *set); |
| 78 | static int sigprop (int sig); |
| 79 | static void stop (struct proc *); |
| 80 | #ifdef SMP |
| 81 | static void signotify_remote(void *arg); |
| 82 | #endif |
| 83 | |
| 84 | static int filt_sigattach(struct knote *kn); |
| 85 | static void filt_sigdetach(struct knote *kn); |
| 86 | static int filt_signal(struct knote *kn, long hint); |
| 87 | |
| 88 | struct filterops sig_filtops = |
| 89 | { 0, filt_sigattach, filt_sigdetach, filt_signal }; |
| 90 | |
| 91 | static int kern_logsigexit = 1; |
| 92 | SYSCTL_INT(_kern, KERN_LOGSIGEXIT, logsigexit, CTLFLAG_RW, |
| 93 | &kern_logsigexit, 0, |
| 94 | "Log processes quitting on abnormal signals to syslog(3)"); |
| 95 | |
| 96 | /* |
| 97 | * Can process p, with pcred pc, send the signal sig to process q? |
| 98 | */ |
| 99 | #define CANSIGNAL(q, sig) \ |
| 100 | (!p_trespass(curproc->p_ucred, (q)->p_ucred) || \ |
| 101 | ((sig) == SIGCONT && (q)->p_session == curproc->p_session)) |
| 102 | |
| 103 | /* |
| 104 | * Policy -- Can real uid ruid with ucred uc send a signal to process q? |
| 105 | */ |
| 106 | #define CANSIGIO(ruid, uc, q) \ |
| 107 | ((uc)->cr_uid == 0 || \ |
| 108 | (ruid) == (q)->p_ucred->cr_ruid || \ |
| 109 | (uc)->cr_uid == (q)->p_ucred->cr_ruid || \ |
| 110 | (ruid) == (q)->p_ucred->cr_uid || \ |
| 111 | (uc)->cr_uid == (q)->p_ucred->cr_uid) |
| 112 | |
| 113 | int sugid_coredump; |
| 114 | SYSCTL_INT(_kern, OID_AUTO, sugid_coredump, CTLFLAG_RW, |
| 115 | &sugid_coredump, 0, "Enable coredumping set user/group ID processes"); |
| 116 | |
| 117 | static int do_coredump = 1; |
| 118 | SYSCTL_INT(_kern, OID_AUTO, coredump, CTLFLAG_RW, |
| 119 | &do_coredump, 0, "Enable/Disable coredumps"); |
| 120 | |
| 121 | /* |
| 122 | * Signal properties and actions. |
| 123 | * The array below categorizes the signals and their default actions |
| 124 | * according to the following properties: |
| 125 | */ |
| 126 | #define SA_KILL 0x01 /* terminates process by default */ |
| 127 | #define SA_CORE 0x02 /* ditto and coredumps */ |
| 128 | #define SA_STOP 0x04 /* suspend process */ |
| 129 | #define SA_TTYSTOP 0x08 /* ditto, from tty */ |
| 130 | #define SA_IGNORE 0x10 /* ignore by default */ |
| 131 | #define SA_CONT 0x20 /* continue if suspended */ |
| 132 | #define SA_CANTMASK 0x40 /* non-maskable, catchable */ |
| 133 | #define SA_CKPT 0x80 /* checkpoint process */ |
| 134 | |
| 135 | |
| 136 | static int sigproptbl[NSIG] = { |
| 137 | SA_KILL, /* SIGHUP */ |
| 138 | SA_KILL, /* SIGINT */ |
| 139 | SA_KILL|SA_CORE, /* SIGQUIT */ |
| 140 | SA_KILL|SA_CORE, /* SIGILL */ |
| 141 | SA_KILL|SA_CORE, /* SIGTRAP */ |
| 142 | SA_KILL|SA_CORE, /* SIGABRT */ |
| 143 | SA_KILL|SA_CORE, /* SIGEMT */ |
| 144 | SA_KILL|SA_CORE, /* SIGFPE */ |
| 145 | SA_KILL, /* SIGKILL */ |
| 146 | SA_KILL|SA_CORE, /* SIGBUS */ |
| 147 | SA_KILL|SA_CORE, /* SIGSEGV */ |
| 148 | SA_KILL|SA_CORE, /* SIGSYS */ |
| 149 | SA_KILL, /* SIGPIPE */ |
| 150 | SA_KILL, /* SIGALRM */ |
| 151 | SA_KILL, /* SIGTERM */ |
| 152 | SA_IGNORE, /* SIGURG */ |
| 153 | SA_STOP, /* SIGSTOP */ |
| 154 | SA_STOP|SA_TTYSTOP, /* SIGTSTP */ |
| 155 | SA_IGNORE|SA_CONT, /* SIGCONT */ |
| 156 | SA_IGNORE, /* SIGCHLD */ |
| 157 | SA_STOP|SA_TTYSTOP, /* SIGTTIN */ |
| 158 | SA_STOP|SA_TTYSTOP, /* SIGTTOU */ |
| 159 | SA_IGNORE, /* SIGIO */ |
| 160 | SA_KILL, /* SIGXCPU */ |
| 161 | SA_KILL, /* SIGXFSZ */ |
| 162 | SA_KILL, /* SIGVTALRM */ |
| 163 | SA_KILL, /* SIGPROF */ |
| 164 | SA_IGNORE, /* SIGWINCH */ |
| 165 | SA_IGNORE, /* SIGINFO */ |
| 166 | SA_KILL, /* SIGUSR1 */ |
| 167 | SA_KILL, /* SIGUSR2 */ |
| 168 | SA_IGNORE, /* SIGTHR */ |
| 169 | SA_CKPT, /* SIGCKPT */ |
| 170 | SA_KILL|SA_CKPT, /* SIGCKPTEXIT */ |
| 171 | SA_IGNORE, |
| 172 | SA_IGNORE, |
| 173 | SA_IGNORE, |
| 174 | SA_IGNORE, |
| 175 | SA_IGNORE, |
| 176 | SA_IGNORE, |
| 177 | SA_IGNORE, |
| 178 | SA_IGNORE, |
| 179 | SA_IGNORE, |
| 180 | SA_IGNORE, |
| 181 | SA_IGNORE, |
| 182 | SA_IGNORE, |
| 183 | SA_IGNORE, |
| 184 | SA_IGNORE, |
| 185 | SA_IGNORE, |
| 186 | SA_IGNORE, |
| 187 | SA_IGNORE, |
| 188 | SA_IGNORE, |
| 189 | SA_IGNORE, |
| 190 | SA_IGNORE, |
| 191 | SA_IGNORE, |
| 192 | SA_IGNORE, |
| 193 | SA_IGNORE, |
| 194 | SA_IGNORE, |
| 195 | SA_IGNORE, |
| 196 | SA_IGNORE, |
| 197 | SA_IGNORE, |
| 198 | SA_IGNORE, |
| 199 | SA_IGNORE, |
| 200 | SA_IGNORE, |
| 201 | |
| 202 | }; |
| 203 | |
| 204 | static __inline int |
| 205 | sigprop(int sig) |
| 206 | { |
| 207 | |
| 208 | if (sig > 0 && sig < NSIG) |
| 209 | return (sigproptbl[_SIG_IDX(sig)]); |
| 210 | return (0); |
| 211 | } |
| 212 | |
| 213 | static __inline int |
| 214 | sig_ffs(sigset_t *set) |
| 215 | { |
| 216 | int i; |
| 217 | |
| 218 | for (i = 0; i < _SIG_WORDS; i++) |
| 219 | if (set->__bits[i]) |
| 220 | return (ffs(set->__bits[i]) + (i * 32)); |
| 221 | return (0); |
| 222 | } |
| 223 | |
| 224 | int |
| 225 | kern_sigaction(int sig, struct sigaction *act, struct sigaction *oact) |
| 226 | { |
| 227 | struct thread *td = curthread; |
| 228 | struct proc *p = td->td_proc; |
| 229 | struct sigacts *ps = p->p_sigacts; |
| 230 | |
| 231 | if (sig <= 0 || sig > _SIG_MAXSIG) |
| 232 | return (EINVAL); |
| 233 | |
| 234 | if (oact) { |
| 235 | oact->sa_handler = ps->ps_sigact[_SIG_IDX(sig)]; |
| 236 | oact->sa_mask = ps->ps_catchmask[_SIG_IDX(sig)]; |
| 237 | oact->sa_flags = 0; |
| 238 | if (SIGISMEMBER(ps->ps_sigonstack, sig)) |
| 239 | oact->sa_flags |= SA_ONSTACK; |
| 240 | if (!SIGISMEMBER(ps->ps_sigintr, sig)) |
| 241 | oact->sa_flags |= SA_RESTART; |
| 242 | if (SIGISMEMBER(ps->ps_sigreset, sig)) |
| 243 | oact->sa_flags |= SA_RESETHAND; |
| 244 | if (SIGISMEMBER(ps->ps_signodefer, sig)) |
| 245 | oact->sa_flags |= SA_NODEFER; |
| 246 | if (SIGISMEMBER(ps->ps_siginfo, sig)) |
| 247 | oact->sa_flags |= SA_SIGINFO; |
| 248 | if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDSTOP) |
| 249 | oact->sa_flags |= SA_NOCLDSTOP; |
| 250 | if (sig == SIGCHLD && p->p_procsig->ps_flag & PS_NOCLDWAIT) |
| 251 | oact->sa_flags |= SA_NOCLDWAIT; |
| 252 | } |
| 253 | if (act) { |
| 254 | if ((sig == SIGKILL || sig == SIGSTOP) && |
| 255 | act->sa_handler != SIG_DFL) |
| 256 | return (EINVAL); |
| 257 | |
| 258 | /* |
| 259 | * Change setting atomically. |
| 260 | */ |
| 261 | (void) splhigh(); |
| 262 | |
| 263 | ps->ps_catchmask[_SIG_IDX(sig)] = act->sa_mask; |
| 264 | SIG_CANTMASK(ps->ps_catchmask[_SIG_IDX(sig)]); |
| 265 | if (act->sa_flags & SA_SIGINFO) { |
| 266 | ps->ps_sigact[_SIG_IDX(sig)] = |
| 267 | (__sighandler_t *)act->sa_sigaction; |
| 268 | SIGADDSET(ps->ps_siginfo, sig); |
| 269 | } else { |
| 270 | ps->ps_sigact[_SIG_IDX(sig)] = act->sa_handler; |
| 271 | SIGDELSET(ps->ps_siginfo, sig); |
| 272 | } |
| 273 | if (!(act->sa_flags & SA_RESTART)) |
| 274 | SIGADDSET(ps->ps_sigintr, sig); |
| 275 | else |
| 276 | SIGDELSET(ps->ps_sigintr, sig); |
| 277 | if (act->sa_flags & SA_ONSTACK) |
| 278 | SIGADDSET(ps->ps_sigonstack, sig); |
| 279 | else |
| 280 | SIGDELSET(ps->ps_sigonstack, sig); |
| 281 | if (act->sa_flags & SA_RESETHAND) |
| 282 | SIGADDSET(ps->ps_sigreset, sig); |
| 283 | else |
| 284 | SIGDELSET(ps->ps_sigreset, sig); |
| 285 | if (act->sa_flags & SA_NODEFER) |
| 286 | SIGADDSET(ps->ps_signodefer, sig); |
| 287 | else |
| 288 | SIGDELSET(ps->ps_signodefer, sig); |
| 289 | if (sig == SIGCHLD) { |
| 290 | if (act->sa_flags & SA_NOCLDSTOP) |
| 291 | p->p_procsig->ps_flag |= PS_NOCLDSTOP; |
| 292 | else |
| 293 | p->p_procsig->ps_flag &= ~PS_NOCLDSTOP; |
| 294 | if (act->sa_flags & SA_NOCLDWAIT) { |
| 295 | /* |
| 296 | * Paranoia: since SA_NOCLDWAIT is implemented |
| 297 | * by reparenting the dying child to PID 1 (and |
| 298 | * trust it to reap the zombie), PID 1 itself |
| 299 | * is forbidden to set SA_NOCLDWAIT. |
| 300 | */ |
| 301 | if (p->p_pid == 1) |
| 302 | p->p_procsig->ps_flag &= ~PS_NOCLDWAIT; |
| 303 | else |
| 304 | p->p_procsig->ps_flag |= PS_NOCLDWAIT; |
| 305 | } else |
| 306 | p->p_procsig->ps_flag &= ~PS_NOCLDWAIT; |
| 307 | } |
| 308 | /* |
| 309 | * Set bit in p_sigignore for signals that are set to SIG_IGN, |
| 310 | * and for signals set to SIG_DFL where the default is to |
| 311 | * ignore. However, don't put SIGCONT in p_sigignore, as we |
| 312 | * have to restart the process. |
| 313 | */ |
| 314 | if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_IGN || |
| 315 | (sigprop(sig) & SA_IGNORE && |
| 316 | ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL)) { |
| 317 | /* never to be seen again */ |
| 318 | SIGDELSET(p->p_siglist, sig); |
| 319 | if (sig != SIGCONT) |
| 320 | /* easier in psignal */ |
| 321 | SIGADDSET(p->p_sigignore, sig); |
| 322 | SIGDELSET(p->p_sigcatch, sig); |
| 323 | } else { |
| 324 | SIGDELSET(p->p_sigignore, sig); |
| 325 | if (ps->ps_sigact[_SIG_IDX(sig)] == SIG_DFL) |
| 326 | SIGDELSET(p->p_sigcatch, sig); |
| 327 | else |
| 328 | SIGADDSET(p->p_sigcatch, sig); |
| 329 | } |
| 330 | |
| 331 | (void) spl0(); |
| 332 | } |
| 333 | return (0); |
| 334 | } |
| 335 | |
| 336 | int |
| 337 | sigaction(struct sigaction_args *uap) |
| 338 | { |
| 339 | struct sigaction act, oact; |
| 340 | struct sigaction *actp, *oactp; |
| 341 | int error; |
| 342 | |
| 343 | actp = (uap->act != NULL) ? &act : NULL; |
| 344 | oactp = (uap->oact != NULL) ? &oact : NULL; |
| 345 | if (actp) { |
| 346 | error = copyin(uap->act, actp, sizeof(act)); |
| 347 | if (error) |
| 348 | return (error); |
| 349 | } |
| 350 | error = kern_sigaction(uap->sig, actp, oactp); |
| 351 | if (oactp && !error) { |
| 352 | error = copyout(oactp, uap->oact, sizeof(oact)); |
| 353 | } |
| 354 | return (error); |
| 355 | } |
| 356 | |
| 357 | /* |
| 358 | * Initialize signal state for process 0; |
| 359 | * set to ignore signals that are ignored by default. |
| 360 | */ |
| 361 | void |
| 362 | siginit(p) |
| 363 | struct proc *p; |
| 364 | { |
| 365 | int i; |
| 366 | |
| 367 | for (i = 1; i <= NSIG; i++) |
| 368 | if (sigprop(i) & SA_IGNORE && i != SIGCONT) |
| 369 | SIGADDSET(p->p_sigignore, i); |
| 370 | } |
| 371 | |
| 372 | /* |
| 373 | * Reset signals for an exec of the specified process. |
| 374 | */ |
| 375 | void |
| 376 | execsigs(p) |
| 377 | struct proc *p; |
| 378 | { |
| 379 | struct sigacts *ps = p->p_sigacts; |
| 380 | int sig; |
| 381 | |
| 382 | /* |
| 383 | * Reset caught signals. Held signals remain held |
| 384 | * through p_sigmask (unless they were caught, |
| 385 | * and are now ignored by default). |
| 386 | */ |
| 387 | while (SIGNOTEMPTY(p->p_sigcatch)) { |
| 388 | sig = sig_ffs(&p->p_sigcatch); |
| 389 | SIGDELSET(p->p_sigcatch, sig); |
| 390 | if (sigprop(sig) & SA_IGNORE) { |
| 391 | if (sig != SIGCONT) |
| 392 | SIGADDSET(p->p_sigignore, sig); |
| 393 | SIGDELSET(p->p_siglist, sig); |
| 394 | } |
| 395 | ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; |
| 396 | } |
| 397 | /* |
| 398 | * Reset stack state to the user stack. |
| 399 | * Clear set of signals caught on the signal stack. |
| 400 | */ |
| 401 | p->p_sigstk.ss_flags = SS_DISABLE; |
| 402 | p->p_sigstk.ss_size = 0; |
| 403 | p->p_sigstk.ss_sp = 0; |
| 404 | p->p_flag &= ~P_ALTSTACK; |
| 405 | /* |
| 406 | * Reset no zombies if child dies flag as Solaris does. |
| 407 | */ |
| 408 | p->p_procsig->ps_flag &= ~PS_NOCLDWAIT; |
| 409 | } |
| 410 | |
| 411 | /* |
| 412 | * kern_sigprocmask() - MP SAFE ONLY IF p == curproc |
| 413 | * |
| 414 | * Manipulate signal mask. This routine is MP SAFE *ONLY* if |
| 415 | * p == curproc. Also remember that in order to remain MP SAFE |
| 416 | * no spl*() calls may be made. |
| 417 | */ |
| 418 | int |
| 419 | kern_sigprocmask(int how, sigset_t *set, sigset_t *oset) |
| 420 | { |
| 421 | struct thread *td = curthread; |
| 422 | struct proc *p = td->td_proc; |
| 423 | int error; |
| 424 | |
| 425 | if (oset != NULL) |
| 426 | *oset = p->p_sigmask; |
| 427 | |
| 428 | error = 0; |
| 429 | if (set != NULL) { |
| 430 | switch (how) { |
| 431 | case SIG_BLOCK: |
| 432 | SIG_CANTMASK(*set); |
| 433 | SIGSETOR(p->p_sigmask, *set); |
| 434 | break; |
| 435 | case SIG_UNBLOCK: |
| 436 | SIGSETNAND(p->p_sigmask, *set); |
| 437 | break; |
| 438 | case SIG_SETMASK: |
| 439 | SIG_CANTMASK(*set); |
| 440 | p->p_sigmask = *set; |
| 441 | break; |
| 442 | default: |
| 443 | error = EINVAL; |
| 444 | break; |
| 445 | } |
| 446 | } |
| 447 | return (error); |
| 448 | } |
| 449 | |
| 450 | /* |
| 451 | * sigprocmask() - MP SAFE |
| 452 | */ |
| 453 | int |
| 454 | sigprocmask(struct sigprocmask_args *uap) |
| 455 | { |
| 456 | sigset_t set, oset; |
| 457 | sigset_t *setp, *osetp; |
| 458 | int error; |
| 459 | |
| 460 | setp = (uap->set != NULL) ? &set : NULL; |
| 461 | osetp = (uap->oset != NULL) ? &oset : NULL; |
| 462 | if (setp) { |
| 463 | error = copyin(uap->set, setp, sizeof(set)); |
| 464 | if (error) |
| 465 | return (error); |
| 466 | } |
| 467 | error = kern_sigprocmask(uap->how, setp, osetp); |
| 468 | if (osetp && !error) { |
| 469 | error = copyout(osetp, uap->oset, sizeof(oset)); |
| 470 | } |
| 471 | return (error); |
| 472 | } |
| 473 | |
| 474 | int |
| 475 | kern_sigpending(struct __sigset *set) |
| 476 | { |
| 477 | struct thread *td = curthread; |
| 478 | struct proc *p = td->td_proc; |
| 479 | |
| 480 | *set = p->p_siglist; |
| 481 | |
| 482 | return (0); |
| 483 | } |
| 484 | |
| 485 | int |
| 486 | sigpending(struct sigpending_args *uap) |
| 487 | { |
| 488 | sigset_t set; |
| 489 | int error; |
| 490 | |
| 491 | error = kern_sigpending(&set); |
| 492 | |
| 493 | if (error == 0) |
| 494 | error = copyout(&set, uap->set, sizeof(set)); |
| 495 | return (error); |
| 496 | } |
| 497 | |
| 498 | /* |
| 499 | * Suspend process until signal, providing mask to be set |
| 500 | * in the meantime. |
| 501 | */ |
| 502 | int |
| 503 | kern_sigsuspend(struct __sigset *set) |
| 504 | { |
| 505 | struct thread *td = curthread; |
| 506 | struct proc *p = td->td_proc; |
| 507 | struct sigacts *ps = p->p_sigacts; |
| 508 | |
| 509 | /* |
| 510 | * When returning from sigsuspend, we want |
| 511 | * the old mask to be restored after the |
| 512 | * signal handler has finished. Thus, we |
| 513 | * save it here and mark the sigacts structure |
| 514 | * to indicate this. |
| 515 | */ |
| 516 | p->p_oldsigmask = p->p_sigmask; |
| 517 | p->p_flag |= P_OLDMASK; |
| 518 | |
| 519 | SIG_CANTMASK(*set); |
| 520 | p->p_sigmask = *set; |
| 521 | while (tsleep(ps, PCATCH, "pause", 0) == 0) |
| 522 | /* void */; |
| 523 | /* always return EINTR rather than ERESTART... */ |
| 524 | return (EINTR); |
| 525 | } |
| 526 | |
| 527 | /* |
| 528 | * Note nonstandard calling convention: libc stub passes mask, not |
| 529 | * pointer, to save a copyin. |
| 530 | */ |
| 531 | int |
| 532 | sigsuspend(struct sigsuspend_args *uap) |
| 533 | { |
| 534 | sigset_t mask; |
| 535 | int error; |
| 536 | |
| 537 | error = copyin(uap->sigmask, &mask, sizeof(mask)); |
| 538 | if (error) |
| 539 | return (error); |
| 540 | |
| 541 | error = kern_sigsuspend(&mask); |
| 542 | |
| 543 | return (error); |
| 544 | } |
| 545 | |
| 546 | int |
| 547 | kern_sigaltstack(struct sigaltstack *ss, struct sigaltstack *oss) |
| 548 | { |
| 549 | struct thread *td = curthread; |
| 550 | struct proc *p = td->td_proc; |
| 551 | |
| 552 | if ((p->p_flag & P_ALTSTACK) == 0) |
| 553 | p->p_sigstk.ss_flags |= SS_DISABLE; |
| 554 | |
| 555 | if (oss) |
| 556 | *oss = p->p_sigstk; |
| 557 | |
| 558 | if (ss) { |
| 559 | if (ss->ss_flags & SS_DISABLE) { |
| 560 | if (p->p_sigstk.ss_flags & SS_ONSTACK) |
| 561 | return (EINVAL); |
| 562 | p->p_flag &= ~P_ALTSTACK; |
| 563 | p->p_sigstk.ss_flags = ss->ss_flags; |
| 564 | } else { |
| 565 | if (ss->ss_size < p->p_sysent->sv_minsigstksz) |
| 566 | return (ENOMEM); |
| 567 | p->p_flag |= P_ALTSTACK; |
| 568 | p->p_sigstk = *ss; |
| 569 | } |
| 570 | } |
| 571 | |
| 572 | return (0); |
| 573 | } |
| 574 | |
| 575 | int |
| 576 | sigaltstack(struct sigaltstack_args *uap) |
| 577 | { |
| 578 | stack_t ss, oss; |
| 579 | int error; |
| 580 | |
| 581 | if (uap->ss) { |
| 582 | error = copyin(uap->ss, &ss, sizeof(ss)); |
| 583 | if (error) |
| 584 | return (error); |
| 585 | } |
| 586 | |
| 587 | error = kern_sigaltstack(uap->ss ? &ss : NULL, |
| 588 | uap->oss ? &oss : NULL); |
| 589 | |
| 590 | if (error == 0 && uap->oss) |
| 591 | error = copyout(&oss, uap->oss, sizeof(*uap->oss)); |
| 592 | return (error); |
| 593 | } |
| 594 | |
| 595 | /* |
| 596 | * Common code for kill process group/broadcast kill. |
| 597 | * cp is calling process. |
| 598 | */ |
| 599 | static int |
| 600 | killpg(int sig, int pgid, int all) |
| 601 | { |
| 602 | struct proc *cp = curproc; |
| 603 | struct proc *p; |
| 604 | struct pgrp *pgrp; |
| 605 | int nfound = 0; |
| 606 | |
| 607 | if (all) |
| 608 | /* |
| 609 | * broadcast |
| 610 | */ |
| 611 | FOREACH_PROC_IN_SYSTEM(p) { |
| 612 | if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || |
| 613 | p == cp || !CANSIGNAL(p, sig)) |
| 614 | continue; |
| 615 | nfound++; |
| 616 | if (sig) |
| 617 | psignal(p, sig); |
| 618 | } |
| 619 | else { |
| 620 | if (pgid == 0) |
| 621 | /* |
| 622 | * zero pgid means send to my process group. |
| 623 | */ |
| 624 | pgrp = cp->p_pgrp; |
| 625 | else { |
| 626 | pgrp = pgfind(pgid); |
| 627 | if (pgrp == NULL) |
| 628 | return (ESRCH); |
| 629 | } |
| 630 | LIST_FOREACH(p, &pgrp->pg_members, p_pglist) { |
| 631 | if (p->p_pid <= 1 || p->p_flag & P_SYSTEM || |
| 632 | p->p_stat == SZOMB || |
| 633 | !CANSIGNAL(p, sig)) |
| 634 | continue; |
| 635 | nfound++; |
| 636 | if (sig) |
| 637 | psignal(p, sig); |
| 638 | } |
| 639 | } |
| 640 | return (nfound ? 0 : ESRCH); |
| 641 | } |
| 642 | |
| 643 | int |
| 644 | kern_kill(int sig, int pid) |
| 645 | { |
| 646 | struct thread *td = curthread; |
| 647 | struct proc *p = td->td_proc; |
| 648 | |
| 649 | if ((u_int)sig > _SIG_MAXSIG) |
| 650 | return (EINVAL); |
| 651 | if (pid > 0) { |
| 652 | /* kill single process */ |
| 653 | if ((p = pfind(pid)) == NULL) |
| 654 | return (ESRCH); |
| 655 | if (!CANSIGNAL(p, sig)) |
| 656 | return (EPERM); |
| 657 | if (sig) |
| 658 | psignal(p, sig); |
| 659 | return (0); |
| 660 | } |
| 661 | switch (pid) { |
| 662 | case -1: /* broadcast signal */ |
| 663 | return (killpg(sig, 0, 1)); |
| 664 | case 0: /* signal own process group */ |
| 665 | return (killpg(sig, 0, 0)); |
| 666 | default: /* negative explicit process group */ |
| 667 | return (killpg(sig, -pid, 0)); |
| 668 | } |
| 669 | /* NOTREACHED */ |
| 670 | } |
| 671 | |
| 672 | int |
| 673 | kill(struct kill_args *uap) |
| 674 | { |
| 675 | int error; |
| 676 | |
| 677 | error = kern_kill(uap->signum, uap->pid); |
| 678 | |
| 679 | return (error); |
| 680 | } |
| 681 | |
| 682 | /* |
| 683 | * Send a signal to a process group. |
| 684 | */ |
| 685 | void |
| 686 | gsignal(int pgid, int sig) |
| 687 | { |
| 688 | struct pgrp *pgrp; |
| 689 | |
| 690 | if (pgid && (pgrp = pgfind(pgid))) |
| 691 | pgsignal(pgrp, sig, 0); |
| 692 | } |
| 693 | |
| 694 | /* |
| 695 | * Send a signal to a process group. If checktty is 1, |
| 696 | * limit to members which have a controlling terminal. |
| 697 | */ |
| 698 | void |
| 699 | pgsignal(pgrp, sig, checkctty) |
| 700 | struct pgrp *pgrp; |
| 701 | int sig, checkctty; |
| 702 | { |
| 703 | struct proc *p; |
| 704 | |
| 705 | if (pgrp) |
| 706 | LIST_FOREACH(p, &pgrp->pg_members, p_pglist) |
| 707 | if (checkctty == 0 || p->p_flag & P_CONTROLT) |
| 708 | psignal(p, sig); |
| 709 | } |
| 710 | |
| 711 | /* |
| 712 | * Send a signal caused by a trap to the current process. |
| 713 | * If it will be caught immediately, deliver it with correct code. |
| 714 | * Otherwise, post it normally. |
| 715 | */ |
| 716 | void |
| 717 | trapsignal(p, sig, code) |
| 718 | struct proc *p; |
| 719 | int sig; |
| 720 | u_long code; |
| 721 | { |
| 722 | struct sigacts *ps = p->p_sigacts; |
| 723 | |
| 724 | if ((p->p_flag & P_TRACED) == 0 && SIGISMEMBER(p->p_sigcatch, sig) && |
| 725 | !SIGISMEMBER(p->p_sigmask, sig)) { |
| 726 | p->p_stats->p_ru.ru_nsignals++; |
| 727 | #ifdef KTRACE |
| 728 | if (KTRPOINT(p->p_thread, KTR_PSIG)) |
| 729 | ktrpsig(p->p_tracep, sig, ps->ps_sigact[_SIG_IDX(sig)], |
| 730 | &p->p_sigmask, code); |
| 731 | #endif |
| 732 | (*p->p_sysent->sv_sendsig)(ps->ps_sigact[_SIG_IDX(sig)], sig, |
| 733 | &p->p_sigmask, code); |
| 734 | SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); |
| 735 | if (!SIGISMEMBER(ps->ps_signodefer, sig)) |
| 736 | SIGADDSET(p->p_sigmask, sig); |
| 737 | if (SIGISMEMBER(ps->ps_sigreset, sig)) { |
| 738 | /* |
| 739 | * See kern_sigaction() for origin of this code. |
| 740 | */ |
| 741 | SIGDELSET(p->p_sigcatch, sig); |
| 742 | if (sig != SIGCONT && |
| 743 | sigprop(sig) & SA_IGNORE) |
| 744 | SIGADDSET(p->p_sigignore, sig); |
| 745 | ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; |
| 746 | } |
| 747 | } else { |
| 748 | p->p_code = code; /* XXX for core dump/debugger */ |
| 749 | p->p_sig = sig; /* XXX to verify code */ |
| 750 | psignal(p, sig); |
| 751 | } |
| 752 | } |
| 753 | |
| 754 | /* |
| 755 | * Send the signal to the process. If the signal has an action, the action |
| 756 | * is usually performed by the target process rather than the caller; we add |
| 757 | * the signal to the set of pending signals for the process. |
| 758 | * |
| 759 | * Exceptions: |
| 760 | * o When a stop signal is sent to a sleeping process that takes the |
| 761 | * default action, the process is stopped without awakening it. |
| 762 | * o SIGCONT restarts stopped processes (or puts them back to sleep) |
| 763 | * regardless of the signal action (eg, blocked or ignored). |
| 764 | * |
| 765 | * Other ignored signals are discarded immediately. |
| 766 | */ |
| 767 | |
| 768 | /* |
| 769 | * temporary hack to allow checkpoint code to continue to |
| 770 | * be in a module for the moment |
| 771 | */ |
| 772 | |
| 773 | static proc_func_t ckpt_func; |
| 774 | |
| 775 | proc_func_t |
| 776 | register_ckpt_func(proc_func_t func) |
| 777 | { |
| 778 | proc_func_t old_func; |
| 779 | |
| 780 | old_func = ckpt_func; |
| 781 | ckpt_func = func; |
| 782 | return (old_func); |
| 783 | } |
| 784 | |
| 785 | void |
| 786 | psignal(p, sig) |
| 787 | struct proc *p; |
| 788 | int sig; |
| 789 | { |
| 790 | int s, prop; |
| 791 | sig_t action; |
| 792 | |
| 793 | if (sig > _SIG_MAXSIG || sig <= 0) { |
| 794 | printf("psignal: signal %d\n", sig); |
| 795 | panic("psignal signal number"); |
| 796 | } |
| 797 | |
| 798 | s = splhigh(); |
| 799 | KNOTE(&p->p_klist, NOTE_SIGNAL | sig); |
| 800 | splx(s); |
| 801 | |
| 802 | prop = sigprop(sig); |
| 803 | |
| 804 | /* |
| 805 | * If proc is traced, always give parent a chance; |
| 806 | * if signal event is tracked by procfs, give *that* |
| 807 | * a chance, as well. |
| 808 | */ |
| 809 | if ((p->p_flag & P_TRACED) || (p->p_stops & S_SIG)) |
| 810 | action = SIG_DFL; |
| 811 | else { |
| 812 | /* |
| 813 | * If the signal is being ignored, |
| 814 | * then we forget about it immediately. |
| 815 | * (Note: we don't set SIGCONT in p_sigignore, |
| 816 | * and if it is set to SIG_IGN, |
| 817 | * action will be SIG_DFL here.) |
| 818 | */ |
| 819 | if (SIGISMEMBER(p->p_sigignore, sig) || (p->p_flag & P_WEXIT)) |
| 820 | return; |
| 821 | if (SIGISMEMBER(p->p_sigmask, sig)) |
| 822 | action = SIG_HOLD; |
| 823 | else if (SIGISMEMBER(p->p_sigcatch, sig)) |
| 824 | action = SIG_CATCH; |
| 825 | else |
| 826 | action = SIG_DFL; |
| 827 | } |
| 828 | |
| 829 | if (p->p_nice > NZERO && action == SIG_DFL && (prop & SA_KILL) && |
| 830 | (p->p_flag & P_TRACED) == 0) |
| 831 | p->p_nice = NZERO; |
| 832 | |
| 833 | if (prop & SA_CONT) |
| 834 | SIG_STOPSIGMASK(p->p_siglist); |
| 835 | |
| 836 | |
| 837 | if (prop & SA_STOP) { |
| 838 | /* |
| 839 | * If sending a tty stop signal to a member of an orphaned |
| 840 | * process group, discard the signal here if the action |
| 841 | * is default; don't stop the process below if sleeping, |
| 842 | * and don't clear any pending SIGCONT. |
| 843 | */ |
| 844 | if (prop & SA_TTYSTOP && p->p_pgrp->pg_jobc == 0 && |
| 845 | action == SIG_DFL) |
| 846 | return; |
| 847 | SIG_CONTSIGMASK(p->p_siglist); |
| 848 | } |
| 849 | SIGADDSET(p->p_siglist, sig); |
| 850 | |
| 851 | /* |
| 852 | * Defer further processing for signals which are held, |
| 853 | * except that stopped processes must be continued by SIGCONT. |
| 854 | */ |
| 855 | if (action == SIG_HOLD && (!(prop & SA_CONT) || p->p_stat != SSTOP)) |
| 856 | return; |
| 857 | s = splhigh(); |
| 858 | switch (p->p_stat) { |
| 859 | |
| 860 | case SSLEEP: |
| 861 | /* |
| 862 | * If process is sleeping uninterruptibly |
| 863 | * we can't interrupt the sleep... the signal will |
| 864 | * be noticed when the process returns through |
| 865 | * trap() or syscall(). |
| 866 | */ |
| 867 | if ((p->p_flag & P_SINTR) == 0) |
| 868 | goto out; |
| 869 | /* |
| 870 | * Process is sleeping and traced... make it runnable |
| 871 | * so it can discover the signal in issignal() and stop |
| 872 | * for the parent. |
| 873 | */ |
| 874 | if (p->p_flag & P_TRACED) |
| 875 | goto run; |
| 876 | /* |
| 877 | * If SIGCONT is default (or ignored) and process is |
| 878 | * asleep, we are finished; the process should not |
| 879 | * be awakened. |
| 880 | */ |
| 881 | if ((prop & SA_CONT) && action == SIG_DFL) { |
| 882 | SIGDELSET(p->p_siglist, sig); |
| 883 | goto out; |
| 884 | } |
| 885 | /* |
| 886 | * When a sleeping process receives a stop |
| 887 | * signal, process immediately if possible. |
| 888 | * All other (caught or default) signals |
| 889 | * cause the process to run. |
| 890 | */ |
| 891 | if (prop & SA_STOP) { |
| 892 | if (action != SIG_DFL) |
| 893 | goto run; |
| 894 | /* |
| 895 | * If a child holding parent blocked, |
| 896 | * stopping could cause deadlock. |
| 897 | */ |
| 898 | if (p->p_flag & P_PPWAIT) |
| 899 | goto out; |
| 900 | SIGDELSET(p->p_siglist, sig); |
| 901 | p->p_xstat = sig; |
| 902 | if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0) |
| 903 | psignal(p->p_pptr, SIGCHLD); |
| 904 | stop(p); |
| 905 | goto out; |
| 906 | } else |
| 907 | goto run; |
| 908 | /*NOTREACHED*/ |
| 909 | |
| 910 | case SSTOP: |
| 911 | /* |
| 912 | * If traced process is already stopped, |
| 913 | * then no further action is necessary. |
| 914 | */ |
| 915 | if (p->p_flag & P_TRACED) |
| 916 | goto out; |
| 917 | |
| 918 | /* |
| 919 | * Kill signal always sets processes running. |
| 920 | */ |
| 921 | if (sig == SIGKILL) |
| 922 | goto run; |
| 923 | |
| 924 | if (prop & SA_CONT) { |
| 925 | /* |
| 926 | * If SIGCONT is default (or ignored), we continue the |
| 927 | * process but don't leave the signal in p_siglist, as |
| 928 | * it has no further action. If SIGCONT is held, we |
| 929 | * continue the process and leave the signal in |
| 930 | * p_siglist. If the process catches SIGCONT, let it |
| 931 | * handle the signal itself. If it isn't waiting on |
| 932 | * an event, then it goes back to run state. |
| 933 | * Otherwise, process goes back to sleep state. |
| 934 | */ |
| 935 | if (action == SIG_DFL) |
| 936 | SIGDELSET(p->p_siglist, sig); |
| 937 | if (action == SIG_CATCH) |
| 938 | goto run; |
| 939 | if (p->p_wchan == 0) |
| 940 | goto run; |
| 941 | clrrunnable(p, SSLEEP); |
| 942 | goto out; |
| 943 | } |
| 944 | |
| 945 | if (prop & SA_STOP) { |
| 946 | /* |
| 947 | * Already stopped, don't need to stop again. |
| 948 | * (If we did the shell could get confused.) |
| 949 | */ |
| 950 | SIGDELSET(p->p_siglist, sig); |
| 951 | goto out; |
| 952 | } |
| 953 | |
| 954 | /* |
| 955 | * If process is sleeping interruptibly, then simulate a |
| 956 | * wakeup so that when it is continued, it will be made |
| 957 | * runnable and can look at the signal. But don't make |
| 958 | * the process runnable, leave it stopped. |
| 959 | */ |
| 960 | if (p->p_wchan && (p->p_flag & P_SINTR)) |
| 961 | unsleep(p->p_thread); |
| 962 | goto out; |
| 963 | |
| 964 | default: |
| 965 | /* |
| 966 | * SRUN, SIDL, SZOMB do nothing with the signal, |
| 967 | * other than kicking ourselves if we are running. |
| 968 | * It will either never be noticed, or noticed very soon. |
| 969 | * |
| 970 | * For SMP we may have to forward the request to another cpu. |
| 971 | * YYY the MP lock prevents the target process from moving |
| 972 | * to another cpu, see kern/kern_switch.c |
| 973 | */ |
| 974 | #ifdef SMP |
| 975 | if (p == lwkt_preempted_proc()) { |
| 976 | signotify(); |
| 977 | } else { |
| 978 | struct thread *td = p->p_thread; |
| 979 | |
| 980 | if (td->td_gd != mycpu) |
| 981 | lwkt_send_ipiq(td->td_gd, signotify_remote, p); |
| 982 | } |
| 983 | #else |
| 984 | if (p == lwkt_preempted_proc()) |
| 985 | signotify(); |
| 986 | #endif |
| 987 | goto out; |
| 988 | } |
| 989 | /*NOTREACHED*/ |
| 990 | run: |
| 991 | setrunnable(p); |
| 992 | out: |
| 993 | splx(s); |
| 994 | } |
| 995 | |
| 996 | #ifdef SMP |
| 997 | |
| 998 | /* |
| 999 | * This function is called via an IPI. We will be in a critical section but |
| 1000 | * the MP lock will NOT be held. Also note that by the time the ipi message |
| 1001 | * gets to us the process 'p' (arg) may no longer be scheduled or even valid. |
| 1002 | */ |
| 1003 | static void |
| 1004 | signotify_remote(void *arg) |
| 1005 | { |
| 1006 | struct proc *p = arg; |
| 1007 | if (p == lwkt_preempted_proc()) |
| 1008 | signotify(); |
| 1009 | } |
| 1010 | |
| 1011 | #endif |
| 1012 | |
| 1013 | /* |
| 1014 | * If the current process has received a signal that would interrupt a |
| 1015 | * system call, return EINTR or ERESTART as appropriate. |
| 1016 | */ |
| 1017 | int |
| 1018 | iscaught(struct proc *p) |
| 1019 | { |
| 1020 | int sig; |
| 1021 | |
| 1022 | if (p) { |
| 1023 | if ((sig = CURSIG(p)) != 0) { |
| 1024 | if (SIGISMEMBER(p->p_sigacts->ps_sigintr, sig)) |
| 1025 | return (EINTR); |
| 1026 | return (ERESTART); |
| 1027 | } |
| 1028 | } |
| 1029 | return(EWOULDBLOCK); |
| 1030 | } |
| 1031 | |
| 1032 | /* |
| 1033 | * If the current process has received a signal (should be caught or cause |
| 1034 | * termination, should interrupt current syscall), return the signal number. |
| 1035 | * Stop signals with default action are processed immediately, then cleared; |
| 1036 | * they aren't returned. This is checked after each entry to the system for |
| 1037 | * a syscall or trap (though this can usually be done without calling issignal |
| 1038 | * by checking the pending signal masks in the CURSIG macro.) The normal call |
| 1039 | * sequence is |
| 1040 | * |
| 1041 | * while (sig = CURSIG(curproc)) |
| 1042 | * postsig(sig); |
| 1043 | */ |
| 1044 | int |
| 1045 | issignal(p) |
| 1046 | struct proc *p; |
| 1047 | { |
| 1048 | sigset_t mask; |
| 1049 | int sig, prop; |
| 1050 | |
| 1051 | for (;;) { |
| 1052 | int traced = (p->p_flag & P_TRACED) || (p->p_stops & S_SIG); |
| 1053 | |
| 1054 | mask = p->p_siglist; |
| 1055 | SIGSETNAND(mask, p->p_sigmask); |
| 1056 | if (p->p_flag & P_PPWAIT) |
| 1057 | SIG_STOPSIGMASK(mask); |
| 1058 | if (!SIGNOTEMPTY(mask)) /* no signal to send */ |
| 1059 | return (0); |
| 1060 | sig = sig_ffs(&mask); |
| 1061 | |
| 1062 | STOPEVENT(p, S_SIG, sig); |
| 1063 | |
| 1064 | /* |
| 1065 | * We should see pending but ignored signals |
| 1066 | * only if P_TRACED was on when they were posted. |
| 1067 | */ |
| 1068 | if (SIGISMEMBER(p->p_sigignore, sig) && (traced == 0)) { |
| 1069 | SIGDELSET(p->p_siglist, sig); |
| 1070 | continue; |
| 1071 | } |
| 1072 | if (p->p_flag & P_TRACED && (p->p_flag & P_PPWAIT) == 0) { |
| 1073 | /* |
| 1074 | * If traced, always stop, and stay |
| 1075 | * stopped until released by the parent. |
| 1076 | */ |
| 1077 | p->p_xstat = sig; |
| 1078 | psignal(p->p_pptr, SIGCHLD); |
| 1079 | do { |
| 1080 | stop(p); |
| 1081 | mi_switch(); |
| 1082 | } while (!trace_req(p) && p->p_flag & P_TRACED); |
| 1083 | |
| 1084 | /* |
| 1085 | * If parent wants us to take the signal, |
| 1086 | * then it will leave it in p->p_xstat; |
| 1087 | * otherwise we just look for signals again. |
| 1088 | */ |
| 1089 | SIGDELSET(p->p_siglist, sig); /* clear old signal */ |
| 1090 | sig = p->p_xstat; |
| 1091 | if (sig == 0) |
| 1092 | continue; |
| 1093 | |
| 1094 | /* |
| 1095 | * Put the new signal into p_siglist. If the |
| 1096 | * signal is being masked, look for other signals. |
| 1097 | */ |
| 1098 | SIGADDSET(p->p_siglist, sig); |
| 1099 | if (SIGISMEMBER(p->p_sigmask, sig)) |
| 1100 | continue; |
| 1101 | |
| 1102 | /* |
| 1103 | * If the traced bit got turned off, go back up |
| 1104 | * to the top to rescan signals. This ensures |
| 1105 | * that p_sig* and ps_sigact are consistent. |
| 1106 | */ |
| 1107 | if ((p->p_flag & P_TRACED) == 0) |
| 1108 | continue; |
| 1109 | } |
| 1110 | |
| 1111 | prop = sigprop(sig); |
| 1112 | |
| 1113 | /* |
| 1114 | * Decide whether the signal should be returned. |
| 1115 | * Return the signal's number, or fall through |
| 1116 | * to clear it from the pending mask. |
| 1117 | */ |
| 1118 | switch ((int)(intptr_t)p->p_sigacts->ps_sigact[_SIG_IDX(sig)]) { |
| 1119 | |
| 1120 | case (int)SIG_DFL: |
| 1121 | /* |
| 1122 | * Don't take default actions on system processes. |
| 1123 | */ |
| 1124 | if (p->p_pid <= 1) { |
| 1125 | #ifdef DIAGNOSTIC |
| 1126 | /* |
| 1127 | * Are you sure you want to ignore SIGSEGV |
| 1128 | * in init? XXX |
| 1129 | */ |
| 1130 | printf("Process (pid %lu) got signal %d\n", |
| 1131 | (u_long)p->p_pid, sig); |
| 1132 | #endif |
| 1133 | break; /* == ignore */ |
| 1134 | } |
| 1135 | |
| 1136 | /* |
| 1137 | * Handle the in-kernel checkpoint action |
| 1138 | */ |
| 1139 | if (prop & SA_CKPT) { |
| 1140 | if (ckpt_func) |
| 1141 | ckpt_func(p); |
| 1142 | break; |
| 1143 | } |
| 1144 | |
| 1145 | /* |
| 1146 | * If there is a pending stop signal to process |
| 1147 | * with default action, stop here, |
| 1148 | * then clear the signal. However, |
| 1149 | * if process is member of an orphaned |
| 1150 | * process group, ignore tty stop signals. |
| 1151 | */ |
| 1152 | if (prop & SA_STOP) { |
| 1153 | if (p->p_flag & P_TRACED || |
| 1154 | (p->p_pgrp->pg_jobc == 0 && |
| 1155 | prop & SA_TTYSTOP)) |
| 1156 | break; /* == ignore */ |
| 1157 | p->p_xstat = sig; |
| 1158 | stop(p); |
| 1159 | if ((p->p_pptr->p_procsig->ps_flag & PS_NOCLDSTOP) == 0) |
| 1160 | psignal(p->p_pptr, SIGCHLD); |
| 1161 | mi_switch(); |
| 1162 | break; |
| 1163 | } else if (prop & SA_IGNORE) { |
| 1164 | /* |
| 1165 | * Except for SIGCONT, shouldn't get here. |
| 1166 | * Default action is to ignore; drop it. |
| 1167 | */ |
| 1168 | break; /* == ignore */ |
| 1169 | } else |
| 1170 | return (sig); |
| 1171 | /*NOTREACHED*/ |
| 1172 | |
| 1173 | case (int)SIG_IGN: |
| 1174 | /* |
| 1175 | * Masking above should prevent us ever trying |
| 1176 | * to take action on an ignored signal other |
| 1177 | * than SIGCONT, unless process is traced. |
| 1178 | */ |
| 1179 | if ((prop & SA_CONT) == 0 && |
| 1180 | (p->p_flag & P_TRACED) == 0) |
| 1181 | printf("issignal\n"); |
| 1182 | break; /* == ignore */ |
| 1183 | |
| 1184 | default: |
| 1185 | /* |
| 1186 | * This signal has an action, let |
| 1187 | * postsig() process it. |
| 1188 | */ |
| 1189 | return (sig); |
| 1190 | } |
| 1191 | SIGDELSET(p->p_siglist, sig); /* take the signal! */ |
| 1192 | } |
| 1193 | /* NOTREACHED */ |
| 1194 | } |
| 1195 | |
| 1196 | /* |
| 1197 | * Put the argument process into the stopped state and notify the parent |
| 1198 | * via wakeup. Signals are handled elsewhere. The process must not be |
| 1199 | * on the run queue. |
| 1200 | */ |
| 1201 | void |
| 1202 | stop(p) |
| 1203 | struct proc *p; |
| 1204 | { |
| 1205 | |
| 1206 | p->p_stat = SSTOP; |
| 1207 | p->p_flag &= ~P_WAITED; |
| 1208 | wakeup((caddr_t)p->p_pptr); |
| 1209 | } |
| 1210 | |
| 1211 | /* |
| 1212 | * Take the action for the specified signal |
| 1213 | * from the current set of pending signals. |
| 1214 | */ |
| 1215 | void |
| 1216 | postsig(sig) |
| 1217 | int sig; |
| 1218 | { |
| 1219 | struct proc *p = curproc; |
| 1220 | struct sigacts *ps = p->p_sigacts; |
| 1221 | sig_t action; |
| 1222 | sigset_t returnmask; |
| 1223 | int code; |
| 1224 | |
| 1225 | KASSERT(sig != 0, ("postsig")); |
| 1226 | |
| 1227 | SIGDELSET(p->p_siglist, sig); |
| 1228 | action = ps->ps_sigact[_SIG_IDX(sig)]; |
| 1229 | #ifdef KTRACE |
| 1230 | if (KTRPOINT(p->p_thread, KTR_PSIG)) |
| 1231 | ktrpsig(p->p_tracep, sig, action, p->p_flag & P_OLDMASK ? |
| 1232 | &p->p_oldsigmask : &p->p_sigmask, 0); |
| 1233 | #endif |
| 1234 | STOPEVENT(p, S_SIG, sig); |
| 1235 | |
| 1236 | if (action == SIG_DFL) { |
| 1237 | /* |
| 1238 | * Default action, where the default is to kill |
| 1239 | * the process. (Other cases were ignored above.) |
| 1240 | */ |
| 1241 | sigexit(p, sig); |
| 1242 | /* NOTREACHED */ |
| 1243 | } else { |
| 1244 | /* |
| 1245 | * If we get here, the signal must be caught. |
| 1246 | */ |
| 1247 | KASSERT(action != SIG_IGN && !SIGISMEMBER(p->p_sigmask, sig), |
| 1248 | ("postsig action")); |
| 1249 | /* |
| 1250 | * Set the new mask value and also defer further |
| 1251 | * occurrences of this signal. |
| 1252 | * |
| 1253 | * Special case: user has done a sigsuspend. Here the |
| 1254 | * current mask is not of interest, but rather the |
| 1255 | * mask from before the sigsuspend is what we want |
| 1256 | * restored after the signal processing is completed. |
| 1257 | */ |
| 1258 | (void) splhigh(); |
| 1259 | if (p->p_flag & P_OLDMASK) { |
| 1260 | returnmask = p->p_oldsigmask; |
| 1261 | p->p_flag &= ~P_OLDMASK; |
| 1262 | } else |
| 1263 | returnmask = p->p_sigmask; |
| 1264 | |
| 1265 | SIGSETOR(p->p_sigmask, ps->ps_catchmask[_SIG_IDX(sig)]); |
| 1266 | if (!SIGISMEMBER(ps->ps_signodefer, sig)) |
| 1267 | SIGADDSET(p->p_sigmask, sig); |
| 1268 | |
| 1269 | if (SIGISMEMBER(ps->ps_sigreset, sig)) { |
| 1270 | /* |
| 1271 | * See kern_sigaction() for origin of this code. |
| 1272 | */ |
| 1273 | SIGDELSET(p->p_sigcatch, sig); |
| 1274 | if (sig != SIGCONT && |
| 1275 | sigprop(sig) & SA_IGNORE) |
| 1276 | SIGADDSET(p->p_sigignore, sig); |
| 1277 | ps->ps_sigact[_SIG_IDX(sig)] = SIG_DFL; |
| 1278 | } |
| 1279 | (void) spl0(); |
| 1280 | p->p_stats->p_ru.ru_nsignals++; |
| 1281 | if (p->p_sig != sig) { |
| 1282 | code = 0; |
| 1283 | } else { |
| 1284 | code = p->p_code; |
| 1285 | p->p_code = 0; |
| 1286 | p->p_sig = 0; |
| 1287 | } |
| 1288 | (*p->p_sysent->sv_sendsig)(action, sig, &returnmask, code); |
| 1289 | } |
| 1290 | } |
| 1291 | |
| 1292 | /* |
| 1293 | * Kill the current process for stated reason. |
| 1294 | */ |
| 1295 | void |
| 1296 | killproc(p, why) |
| 1297 | struct proc *p; |
| 1298 | char *why; |
| 1299 | { |
| 1300 | log(LOG_ERR, "pid %d (%s), uid %d, was killed: %s\n", p->p_pid, p->p_comm, |
| 1301 | p->p_ucred ? p->p_ucred->cr_uid : -1, why); |
| 1302 | psignal(p, SIGKILL); |
| 1303 | } |
| 1304 | |
| 1305 | /* |
| 1306 | * Force the current process to exit with the specified signal, dumping core |
| 1307 | * if appropriate. We bypass the normal tests for masked and caught signals, |
| 1308 | * allowing unrecoverable failures to terminate the process without changing |
| 1309 | * signal state. Mark the accounting record with the signal termination. |
| 1310 | * If dumping core, save the signal number for the debugger. Calls exit and |
| 1311 | * does not return. |
| 1312 | */ |
| 1313 | void |
| 1314 | sigexit(struct proc *p, int sig) |
| 1315 | { |
| 1316 | p->p_acflag |= AXSIG; |
| 1317 | if (sigprop(sig) & SA_CORE) { |
| 1318 | p->p_sig = sig; |
| 1319 | /* |
| 1320 | * Log signals which would cause core dumps |
| 1321 | * (Log as LOG_INFO to appease those who don't want |
| 1322 | * these messages.) |
| 1323 | * XXX : Todo, as well as euid, write out ruid too |
| 1324 | */ |
| 1325 | if (coredump(p) == 0) |
| 1326 | sig |= WCOREFLAG; |
| 1327 | if (kern_logsigexit) |
| 1328 | log(LOG_INFO, |
| 1329 | "pid %d (%s), uid %d: exited on signal %d%s\n", |
| 1330 | p->p_pid, p->p_comm, |
| 1331 | p->p_ucred ? p->p_ucred->cr_uid : -1, |
| 1332 | sig &~ WCOREFLAG, |
| 1333 | sig & WCOREFLAG ? " (core dumped)" : ""); |
| 1334 | } |
| 1335 | exit1(W_EXITCODE(0, sig)); |
| 1336 | /* NOTREACHED */ |
| 1337 | } |
| 1338 | |
| 1339 | static char corefilename[MAXPATHLEN+1] = {"%N.core"}; |
| 1340 | SYSCTL_STRING(_kern, OID_AUTO, corefile, CTLFLAG_RW, corefilename, |
| 1341 | sizeof(corefilename), "process corefile name format string"); |
| 1342 | |
| 1343 | /* |
| 1344 | * expand_name(name, uid, pid) |
| 1345 | * Expand the name described in corefilename, using name, uid, and pid. |
| 1346 | * corefilename is a printf-like string, with three format specifiers: |
| 1347 | * %N name of process ("name") |
| 1348 | * %P process id (pid) |
| 1349 | * %U user id (uid) |
| 1350 | * For example, "%N.core" is the default; they can be disabled completely |
| 1351 | * by using "/dev/null", or all core files can be stored in "/cores/%U/%N-%P". |
| 1352 | * This is controlled by the sysctl variable kern.corefile (see above). |
| 1353 | */ |
| 1354 | |
| 1355 | static char * |
| 1356 | expand_name(name, uid, pid) |
| 1357 | const char *name; uid_t uid; pid_t pid; { |
| 1358 | char *temp; |
| 1359 | char buf[11]; /* Buffer for pid/uid -- max 4B */ |
| 1360 | int i, n; |
| 1361 | char *format = corefilename; |
| 1362 | size_t namelen; |
| 1363 | |
| 1364 | temp = malloc(MAXPATHLEN + 1, M_TEMP, M_NOWAIT); |
| 1365 | if (temp == NULL) |
| 1366 | return NULL; |
| 1367 | namelen = strlen(name); |
| 1368 | for (i = 0, n = 0; n < MAXPATHLEN && format[i]; i++) { |
| 1369 | int l; |
| 1370 | switch (format[i]) { |
| 1371 | case '%': /* Format character */ |
| 1372 | i++; |
| 1373 | switch (format[i]) { |
| 1374 | case '%': |
| 1375 | temp[n++] = '%'; |
| 1376 | break; |
| 1377 | case 'N': /* process name */ |
| 1378 | if ((n + namelen) > MAXPATHLEN) { |
| 1379 | log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", |
| 1380 | pid, name, uid, temp, name); |
| 1381 | free(temp, M_TEMP); |
| 1382 | return NULL; |
| 1383 | } |
| 1384 | memcpy(temp+n, name, namelen); |
| 1385 | n += namelen; |
| 1386 | break; |
| 1387 | case 'P': /* process id */ |
| 1388 | l = sprintf(buf, "%u", pid); |
| 1389 | if ((n + l) > MAXPATHLEN) { |
| 1390 | log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", |
| 1391 | pid, name, uid, temp, name); |
| 1392 | free(temp, M_TEMP); |
| 1393 | return NULL; |
| 1394 | } |
| 1395 | memcpy(temp+n, buf, l); |
| 1396 | n += l; |
| 1397 | break; |
| 1398 | case 'U': /* user id */ |
| 1399 | l = sprintf(buf, "%u", uid); |
| 1400 | if ((n + l) > MAXPATHLEN) { |
| 1401 | log(LOG_ERR, "pid %d (%s), uid (%u): Path `%s%s' is too long\n", |
| 1402 | pid, name, uid, temp, name); |
| 1403 | free(temp, M_TEMP); |
| 1404 | return NULL; |
| 1405 | } |
| 1406 | memcpy(temp+n, buf, l); |
| 1407 | n += l; |
| 1408 | break; |
| 1409 | default: |
| 1410 | log(LOG_ERR, "Unknown format character %c in `%s'\n", format[i], format); |
| 1411 | } |
| 1412 | break; |
| 1413 | default: |
| 1414 | temp[n++] = format[i]; |
| 1415 | } |
| 1416 | } |
| 1417 | temp[n] = '\0'; |
| 1418 | return temp; |
| 1419 | } |
| 1420 | |
| 1421 | /* |
| 1422 | * Dump a process' core. The main routine does some |
| 1423 | * policy checking, and creates the name of the coredump; |
| 1424 | * then it passes on a vnode and a size limit to the process-specific |
| 1425 | * coredump routine if there is one; if there _is not_ one, it returns |
| 1426 | * ENOSYS; otherwise it returns the error from the process-specific routine. |
| 1427 | */ |
| 1428 | |
| 1429 | static int |
| 1430 | coredump(struct proc *p) |
| 1431 | { |
| 1432 | struct vnode *vp; |
| 1433 | struct ucred *cred = p->p_ucred; |
| 1434 | struct thread *td = p->p_thread; |
| 1435 | struct flock lf; |
| 1436 | struct nameidata nd; |
| 1437 | struct vattr vattr; |
| 1438 | int error, error1; |
| 1439 | char *name; /* name of corefile */ |
| 1440 | off_t limit; |
| 1441 | |
| 1442 | STOPEVENT(p, S_CORE, 0); |
| 1443 | |
| 1444 | if (((sugid_coredump == 0) && p->p_flag & P_SUGID) || do_coredump == 0) |
| 1445 | return (EFAULT); |
| 1446 | |
| 1447 | /* |
| 1448 | * Note that the bulk of limit checking is done after |
| 1449 | * the corefile is created. The exception is if the limit |
| 1450 | * for corefiles is 0, in which case we don't bother |
| 1451 | * creating the corefile at all. This layout means that |
| 1452 | * a corefile is truncated instead of not being created, |
| 1453 | * if it is larger than the limit. |
| 1454 | */ |
| 1455 | limit = p->p_rlimit[RLIMIT_CORE].rlim_cur; |
| 1456 | if (limit == 0) |
| 1457 | return EFBIG; |
| 1458 | |
| 1459 | name = expand_name(p->p_comm, p->p_ucred->cr_uid, p->p_pid); |
| 1460 | if (name == NULL) |
| 1461 | return (EINVAL); |
| 1462 | NDINIT(&nd, NAMEI_LOOKUP, 0, UIO_SYSSPACE, name, td); |
| 1463 | error = vn_open(&nd, O_CREAT | FWRITE | O_NOFOLLOW, S_IRUSR | S_IWUSR); |
| 1464 | free(name, M_TEMP); |
| 1465 | if (error) |
| 1466 | return (error); |
| 1467 | NDFREE(&nd, NDF_ONLY_PNBUF); |
| 1468 | vp = nd.ni_vp; |
| 1469 | |
| 1470 | VOP_UNLOCK(vp, NULL, 0, td); |
| 1471 | lf.l_whence = SEEK_SET; |
| 1472 | lf.l_start = 0; |
| 1473 | lf.l_len = 0; |
| 1474 | lf.l_type = F_WRLCK; |
| 1475 | error = VOP_ADVLOCK(vp, (caddr_t)p, F_SETLK, &lf, F_FLOCK); |
| 1476 | if (error) |
| 1477 | goto out2; |
| 1478 | |
| 1479 | /* Don't dump to non-regular files or files with links. */ |
| 1480 | if (vp->v_type != VREG || |
| 1481 | VOP_GETATTR(vp, &vattr, td) || vattr.va_nlink != 1) { |
| 1482 | error = EFAULT; |
| 1483 | goto out1; |
| 1484 | } |
| 1485 | |
| 1486 | VATTR_NULL(&vattr); |
| 1487 | vn_lock(vp, NULL, LK_EXCLUSIVE | LK_RETRY, td); |
| 1488 | vattr.va_size = 0; |
| 1489 | VOP_LEASE(vp, td, cred, LEASE_WRITE); |
| 1490 | VOP_SETATTR(vp, &vattr, cred, td); |
| 1491 | p->p_acflag |= ACORE; |
| 1492 | VOP_UNLOCK(vp, NULL, 0, td); |
| 1493 | |
| 1494 | error = p->p_sysent->sv_coredump ? |
| 1495 | p->p_sysent->sv_coredump(p, vp, limit) : |
| 1496 | ENOSYS; |
| 1497 | |
| 1498 | out1: |
| 1499 | lf.l_type = F_UNLCK; |
| 1500 | VOP_ADVLOCK(vp, (caddr_t)p, F_UNLCK, &lf, F_FLOCK); |
| 1501 | out2: |
| 1502 | error1 = vn_close(vp, FWRITE, td); |
| 1503 | if (error == 0) |
| 1504 | error = error1; |
| 1505 | return (error); |
| 1506 | } |
| 1507 | |
| 1508 | /* |
| 1509 | * Nonexistent system call-- signal process (may want to handle it). |
| 1510 | * Flag error in case process won't see signal immediately (blocked or ignored). |
| 1511 | */ |
| 1512 | /* ARGSUSED */ |
| 1513 | int |
| 1514 | nosys(struct nosys_args *args) |
| 1515 | { |
| 1516 | psignal(curproc, SIGSYS); |
| 1517 | return (EINVAL); |
| 1518 | } |
| 1519 | |
| 1520 | /* |
| 1521 | * Send a SIGIO or SIGURG signal to a process or process group using |
| 1522 | * stored credentials rather than those of the current process. |
| 1523 | */ |
| 1524 | void |
| 1525 | pgsigio(struct sigio *sigio, int sig, int checkctty) |
| 1526 | { |
| 1527 | if (sigio == NULL) |
| 1528 | return; |
| 1529 | |
| 1530 | if (sigio->sio_pgid > 0) { |
| 1531 | if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, |
| 1532 | sigio->sio_proc)) |
| 1533 | psignal(sigio->sio_proc, sig); |
| 1534 | } else if (sigio->sio_pgid < 0) { |
| 1535 | struct proc *p; |
| 1536 | |
| 1537 | LIST_FOREACH(p, &sigio->sio_pgrp->pg_members, p_pglist) |
| 1538 | if (CANSIGIO(sigio->sio_ruid, sigio->sio_ucred, p) && |
| 1539 | (checkctty == 0 || (p->p_flag & P_CONTROLT))) |
| 1540 | psignal(p, sig); |
| 1541 | } |
| 1542 | } |
| 1543 | |
| 1544 | static int |
| 1545 | filt_sigattach(struct knote *kn) |
| 1546 | { |
| 1547 | struct proc *p = curproc; |
| 1548 | |
| 1549 | kn->kn_ptr.p_proc = p; |
| 1550 | kn->kn_flags |= EV_CLEAR; /* automatically set */ |
| 1551 | |
| 1552 | /* XXX lock the proc here while adding to the list? */ |
| 1553 | SLIST_INSERT_HEAD(&p->p_klist, kn, kn_selnext); |
| 1554 | |
| 1555 | return (0); |
| 1556 | } |
| 1557 | |
| 1558 | static void |
| 1559 | filt_sigdetach(struct knote *kn) |
| 1560 | { |
| 1561 | struct proc *p = kn->kn_ptr.p_proc; |
| 1562 | |
| 1563 | SLIST_REMOVE(&p->p_klist, kn, knote, kn_selnext); |
| 1564 | } |
| 1565 | |
| 1566 | /* |
| 1567 | * signal knotes are shared with proc knotes, so we apply a mask to |
| 1568 | * the hint in order to differentiate them from process hints. This |
| 1569 | * could be avoided by using a signal-specific knote list, but probably |
| 1570 | * isn't worth the trouble. |
| 1571 | */ |
| 1572 | static int |
| 1573 | filt_signal(struct knote *kn, long hint) |
| 1574 | { |
| 1575 | |
| 1576 | if (hint & NOTE_SIGNAL) { |
| 1577 | hint &= ~NOTE_SIGNAL; |
| 1578 | |
| 1579 | if (kn->kn_id == hint) |
| 1580 | kn->kn_data++; |
| 1581 | } |
| 1582 | return (kn->kn_data != 0); |
| 1583 | } |