The Android Open Source Project | 4f6e8d7 | 2008-10-21 07:00:00 -0700 | [diff] [blame^] | 1 | /* $NetBSD: trap.c,v 1.31 2005/01/11 19:38:57 christos Exp $ */ |
| 2 | |
| 3 | /*- |
| 4 | * Copyright (c) 1991, 1993 |
| 5 | * The Regents of the University of California. All rights reserved. |
| 6 | * |
| 7 | * This code is derived from software contributed to Berkeley by |
| 8 | * Kenneth Almquist. |
| 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. Neither the name of the University nor the names of its contributors |
| 19 | * may be used to endorse or promote products derived from this software |
| 20 | * without specific prior written permission. |
| 21 | * |
| 22 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND |
| 23 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
| 24 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
| 25 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE |
| 26 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL |
| 27 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS |
| 28 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) |
| 29 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT |
| 30 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY |
| 31 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF |
| 32 | * SUCH DAMAGE. |
| 33 | */ |
| 34 | |
| 35 | #include <sys/cdefs.h> |
| 36 | #ifndef lint |
| 37 | #if 0 |
| 38 | static char sccsid[] = "@(#)trap.c 8.5 (Berkeley) 6/5/95"; |
| 39 | #else |
| 40 | __RCSID("$NetBSD: trap.c,v 1.31 2005/01/11 19:38:57 christos Exp $"); |
| 41 | #endif |
| 42 | #endif /* not lint */ |
| 43 | |
| 44 | #include <signal.h> |
| 45 | #include <unistd.h> |
| 46 | #include <stdlib.h> |
| 47 | |
| 48 | #include "shell.h" |
| 49 | #include "main.h" |
| 50 | #include "nodes.h" /* for other headers */ |
| 51 | #include "eval.h" |
| 52 | #include "jobs.h" |
| 53 | #include "show.h" |
| 54 | #include "options.h" |
| 55 | #include "syntax.h" |
| 56 | #include "output.h" |
| 57 | #include "memalloc.h" |
| 58 | #include "error.h" |
| 59 | #include "trap.h" |
| 60 | #include "mystring.h" |
| 61 | #include "var.h" |
| 62 | |
| 63 | static const char *sys_signame[NSIG] = { |
| 64 | "Unused", |
| 65 | "HUP", "INT", "QUIT", "ILL", |
| 66 | "TRAP", "ABRT", "BUS", "FPE", |
| 67 | "KILL", "USR1", "SEGV", "USR2", |
| 68 | "PIPE", "ALRM", "TERM", |
| 69 | "Unknown", |
| 70 | "CHLD", |
| 71 | "CONT", "STOP", "TSTP", "TTIN", |
| 72 | "TTOU", "URG", "XCPU", "XFSZ", |
| 73 | "VTALRM", "PROF", "WINCH", "IO", |
| 74 | "PWR", "SYS" |
| 75 | }; |
| 76 | |
| 77 | /* |
| 78 | * Sigmode records the current value of the signal handlers for the various |
| 79 | * modes. A value of zero means that the current handler is not known. |
| 80 | * S_HARD_IGN indicates that the signal was ignored on entry to the shell, |
| 81 | */ |
| 82 | |
| 83 | #define S_DFL 1 /* default signal handling (SIG_DFL) */ |
| 84 | #define S_CATCH 2 /* signal is caught */ |
| 85 | #define S_IGN 3 /* signal is ignored (SIG_IGN) */ |
| 86 | #define S_HARD_IGN 4 /* signal is ignored permenantly */ |
| 87 | #define S_RESET 5 /* temporary - to reset a hard ignored sig */ |
| 88 | |
| 89 | |
| 90 | char *trap[NSIG+1]; /* trap handler commands */ |
| 91 | MKINIT char sigmode[NSIG]; /* current value of signal */ |
| 92 | char gotsig[NSIG]; /* indicates specified signal received */ |
| 93 | int pendingsigs; /* indicates some signal received */ |
| 94 | |
| 95 | static int getsigaction(int, sig_t *); |
| 96 | |
| 97 | /* |
| 98 | * return the signal number described by `p' (as a number or a name) |
| 99 | * or -1 if it isn't one |
| 100 | */ |
| 101 | |
| 102 | static int |
| 103 | signame_to_signum(const char *p) |
| 104 | { |
| 105 | int i; |
| 106 | |
| 107 | if (is_number(p)) |
| 108 | return number(p); |
| 109 | |
| 110 | if (strcasecmp(p, "exit") == 0 ) |
| 111 | return 0; |
| 112 | |
| 113 | if (strncasecmp(p, "sig", 3) == 0) |
| 114 | p += 3; |
| 115 | |
| 116 | for (i = 0; i < NSIG; ++i) |
| 117 | if (strcasecmp (p, sys_signame[i]) == 0) |
| 118 | return i; |
| 119 | return -1; |
| 120 | } |
| 121 | |
| 122 | /* |
| 123 | * Print a list of valid signal names |
| 124 | */ |
| 125 | static void |
| 126 | printsignals(void) |
| 127 | { |
| 128 | int n; |
| 129 | |
| 130 | out1str("EXIT "); |
| 131 | |
| 132 | for (n = 1; n < NSIG; n++) { |
| 133 | out1fmt("%s", sys_signame[n]); |
| 134 | if ((n == NSIG/2) || n == (NSIG - 1)) |
| 135 | out1str("\n"); |
| 136 | else |
| 137 | out1c(' '); |
| 138 | } |
| 139 | } |
| 140 | |
| 141 | /* |
| 142 | * The trap builtin. |
| 143 | */ |
| 144 | |
| 145 | int |
| 146 | trapcmd(int argc, char **argv) |
| 147 | { |
| 148 | char *action; |
| 149 | char **ap; |
| 150 | int signo; |
| 151 | |
| 152 | if (argc <= 1) { |
| 153 | for (signo = 0 ; signo <= NSIG ; signo++) |
| 154 | if (trap[signo] != NULL) { |
| 155 | out1fmt("trap -- "); |
| 156 | print_quoted(trap[signo]); |
| 157 | out1fmt(" %s\n", |
| 158 | (signo) ? sys_signame[signo] : "EXIT"); |
| 159 | } |
| 160 | return 0; |
| 161 | } |
| 162 | ap = argv + 1; |
| 163 | |
| 164 | action = NULL; |
| 165 | |
| 166 | if (strcmp(*ap, "--") == 0) |
| 167 | if (*++ap == NULL) |
| 168 | return 0; |
| 169 | |
| 170 | if (signame_to_signum(*ap) == -1) { |
| 171 | if ((*ap)[0] == '-') { |
| 172 | if ((*ap)[1] == '\0') |
| 173 | ap++; |
| 174 | else if ((*ap)[1] == 'l' && (*ap)[2] == '\0') { |
| 175 | printsignals(); |
| 176 | return 0; |
| 177 | } |
| 178 | else |
| 179 | error("bad option %s\n", *ap); |
| 180 | } |
| 181 | else |
| 182 | action = *ap++; |
| 183 | } |
| 184 | |
| 185 | while (*ap) { |
| 186 | if (is_number(*ap)) |
| 187 | signo = number(*ap); |
| 188 | else |
| 189 | signo = signame_to_signum(*ap); |
| 190 | |
| 191 | if (signo < 0 || signo > NSIG) |
| 192 | error("%s: bad trap", *ap); |
| 193 | |
| 194 | INTOFF; |
| 195 | if (action) |
| 196 | action = savestr(action); |
| 197 | |
| 198 | if (trap[signo]) |
| 199 | ckfree(trap[signo]); |
| 200 | |
| 201 | trap[signo] = action; |
| 202 | |
| 203 | if (signo != 0) |
| 204 | setsignal(signo, 0); |
| 205 | INTON; |
| 206 | ap++; |
| 207 | } |
| 208 | return 0; |
| 209 | } |
| 210 | |
| 211 | |
| 212 | |
| 213 | /* |
| 214 | * Clear traps on a fork or vfork. |
| 215 | * Takes one arg vfork, to tell it to not be destructive of |
| 216 | * the parents variables. |
| 217 | */ |
| 218 | |
| 219 | void |
| 220 | clear_traps(int vforked) |
| 221 | { |
| 222 | char **tp; |
| 223 | |
| 224 | for (tp = trap ; tp <= &trap[NSIG] ; tp++) { |
| 225 | if (*tp && **tp) { /* trap not NULL or SIG_IGN */ |
| 226 | INTOFF; |
| 227 | if (!vforked) { |
| 228 | ckfree(*tp); |
| 229 | *tp = NULL; |
| 230 | } |
| 231 | if (tp != &trap[0]) |
| 232 | setsignal(tp - trap, vforked); |
| 233 | INTON; |
| 234 | } |
| 235 | } |
| 236 | } |
| 237 | |
| 238 | |
| 239 | |
| 240 | /* |
| 241 | * Set the signal handler for the specified signal. The routine figures |
| 242 | * out what it should be set to. |
| 243 | */ |
| 244 | |
| 245 | long |
| 246 | setsignal(int signo, int vforked) |
| 247 | { |
| 248 | int action; |
| 249 | sig_t sigact = SIG_DFL; |
| 250 | struct sigaction act, oact; |
| 251 | char *t, tsig; |
| 252 | |
| 253 | if ((t = trap[signo]) == NULL) |
| 254 | action = S_DFL; |
| 255 | else if (*t != '\0') |
| 256 | action = S_CATCH; |
| 257 | else |
| 258 | action = S_IGN; |
| 259 | if (rootshell && !vforked && action == S_DFL) { |
| 260 | switch (signo) { |
| 261 | case SIGINT: |
| 262 | if (iflag || minusc || sflag == 0) |
| 263 | action = S_CATCH; |
| 264 | break; |
| 265 | case SIGQUIT: |
| 266 | #ifdef DEBUG |
| 267 | if (debug) |
| 268 | break; |
| 269 | #endif |
| 270 | /* FALLTHROUGH */ |
| 271 | case SIGTERM: |
| 272 | if (iflag) |
| 273 | action = S_IGN; |
| 274 | break; |
| 275 | #if JOBS |
| 276 | case SIGTSTP: |
| 277 | case SIGTTOU: |
| 278 | if (mflag) |
| 279 | action = S_IGN; |
| 280 | break; |
| 281 | #endif |
| 282 | } |
| 283 | } |
| 284 | |
| 285 | t = &sigmode[signo - 1]; |
| 286 | tsig = *t; |
| 287 | if (tsig == 0) { |
| 288 | /* |
| 289 | * current setting unknown |
| 290 | */ |
| 291 | if (!getsigaction(signo, &sigact)) { |
| 292 | /* |
| 293 | * Pretend it worked; maybe we should give a warning |
| 294 | * here, but other shells don't. We don't alter |
| 295 | * sigmode, so that we retry every time. |
| 296 | */ |
| 297 | return 0; |
| 298 | } |
| 299 | if (sigact == SIG_IGN) { |
| 300 | if (mflag && (signo == SIGTSTP || |
| 301 | signo == SIGTTIN || signo == SIGTTOU)) { |
| 302 | tsig = S_IGN; /* don't hard ignore these */ |
| 303 | } else |
| 304 | tsig = S_HARD_IGN; |
| 305 | } else { |
| 306 | tsig = S_RESET; /* force to be set */ |
| 307 | } |
| 308 | } |
| 309 | if (tsig == S_HARD_IGN || tsig == action) |
| 310 | return 0; |
| 311 | switch (action) { |
| 312 | case S_DFL: sigact = SIG_DFL; break; |
| 313 | case S_CATCH: sigact = onsig; break; |
| 314 | case S_IGN: sigact = SIG_IGN; break; |
| 315 | } |
| 316 | if (!vforked) |
| 317 | *t = action; |
| 318 | act.sa_handler = sigact; |
| 319 | sigemptyset(&act.sa_mask); |
| 320 | act.sa_flags = 0; |
| 321 | #ifdef SA_INTERRUPT |
| 322 | act.sa_flags |= SA_INTERRUPT; |
| 323 | #endif |
| 324 | if(sigaction(signo, &act, &oact) < 0) |
| 325 | return (long) SIG_ERR; |
| 326 | return (long) oact.sa_handler; |
| 327 | } |
| 328 | |
| 329 | /* |
| 330 | * Return the current setting for sig w/o changing it. |
| 331 | */ |
| 332 | static int |
| 333 | getsigaction(int signo, sig_t *sigact) |
| 334 | { |
| 335 | struct sigaction sa; |
| 336 | |
| 337 | if (sigaction(signo, (struct sigaction *)0, &sa) == -1) |
| 338 | return 0; |
| 339 | *sigact = (sig_t) sa.sa_handler; |
| 340 | return 1; |
| 341 | } |
| 342 | |
| 343 | /* |
| 344 | * Ignore a signal. |
| 345 | */ |
| 346 | |
| 347 | void |
| 348 | ignoresig(int signo, int vforked) |
| 349 | { |
| 350 | if (sigmode[signo - 1] != S_IGN && sigmode[signo - 1] != S_HARD_IGN) |
| 351 | bsd_signal(signo, SIG_IGN); |
| 352 | if (!vforked) |
| 353 | sigmode[signo - 1] = S_HARD_IGN; |
| 354 | } |
| 355 | |
| 356 | |
| 357 | #ifdef mkinit |
| 358 | INCLUDE <signal.h> |
| 359 | INCLUDE "trap.h" |
| 360 | |
| 361 | SHELLPROC { |
| 362 | char *sm; |
| 363 | |
| 364 | clear_traps(0); |
| 365 | for (sm = sigmode ; sm < sigmode + NSIG ; sm++) { |
| 366 | if (*sm == S_IGN) |
| 367 | *sm = S_HARD_IGN; |
| 368 | } |
| 369 | } |
| 370 | #endif |
| 371 | |
| 372 | |
| 373 | |
| 374 | /* |
| 375 | * Signal handler. |
| 376 | */ |
| 377 | |
| 378 | void |
| 379 | onsig(int signo) |
| 380 | { |
| 381 | bsd_signal(signo, onsig); |
| 382 | if (signo == SIGINT && trap[SIGINT] == NULL) { |
| 383 | onint(); |
| 384 | return; |
| 385 | } |
| 386 | gotsig[signo - 1] = 1; |
| 387 | pendingsigs++; |
| 388 | } |
| 389 | |
| 390 | |
| 391 | |
| 392 | /* |
| 393 | * Called to execute a trap. Perhaps we should avoid entering new trap |
| 394 | * handlers while we are executing a trap handler. |
| 395 | */ |
| 396 | |
| 397 | void |
| 398 | dotrap(void) |
| 399 | { |
| 400 | int i; |
| 401 | int savestatus; |
| 402 | |
| 403 | for (;;) { |
| 404 | for (i = 1 ; ; i++) { |
| 405 | if (gotsig[i - 1]) |
| 406 | break; |
| 407 | if (i >= NSIG) |
| 408 | goto done; |
| 409 | } |
| 410 | gotsig[i - 1] = 0; |
| 411 | savestatus=exitstatus; |
| 412 | evalstring(trap[i], 0); |
| 413 | exitstatus=savestatus; |
| 414 | } |
| 415 | done: |
| 416 | pendingsigs = 0; |
| 417 | } |
| 418 | |
| 419 | |
| 420 | |
| 421 | /* |
| 422 | * Controls whether the shell is interactive or not. |
| 423 | */ |
| 424 | |
| 425 | |
| 426 | void |
| 427 | setinteractive(int on) |
| 428 | { |
| 429 | static int is_interactive; |
| 430 | |
| 431 | if (on == is_interactive) |
| 432 | return; |
| 433 | setsignal(SIGINT, 0); |
| 434 | setsignal(SIGQUIT, 0); |
| 435 | setsignal(SIGTERM, 0); |
| 436 | is_interactive = on; |
| 437 | } |
| 438 | |
| 439 | |
| 440 | |
| 441 | /* |
| 442 | * Called to exit the shell. |
| 443 | */ |
| 444 | |
| 445 | void |
| 446 | exitshell(int status) |
| 447 | { |
| 448 | struct jmploc loc1, loc2; |
| 449 | char *p; |
| 450 | |
| 451 | TRACE(("pid %d, exitshell(%d)\n", getpid(), status)); |
| 452 | if (setjmp(loc1.loc)) { |
| 453 | goto l1; |
| 454 | } |
| 455 | if (setjmp(loc2.loc)) { |
| 456 | goto l2; |
| 457 | } |
| 458 | handler = &loc1; |
| 459 | if ((p = trap[0]) != NULL && *p != '\0') { |
| 460 | trap[0] = NULL; |
| 461 | evalstring(p, 0); |
| 462 | } |
| 463 | l1: handler = &loc2; /* probably unnecessary */ |
| 464 | flushall(); |
| 465 | #if JOBS |
| 466 | setjobctl(0); |
| 467 | #endif |
| 468 | l2: _exit(status); |
| 469 | /* NOTREACHED */ |
| 470 | } |