trap.c revision 213811
11556Srgrimes/*- 21556Srgrimes * Copyright (c) 1991, 1993 31556Srgrimes * The Regents of the University of California. All rights reserved. 41556Srgrimes * 51556Srgrimes * This code is derived from software contributed to Berkeley by 61556Srgrimes * Kenneth Almquist. 71556Srgrimes * 81556Srgrimes * Redistribution and use in source and binary forms, with or without 91556Srgrimes * modification, are permitted provided that the following conditions 101556Srgrimes * are met: 111556Srgrimes * 1. Redistributions of source code must retain the above copyright 121556Srgrimes * notice, this list of conditions and the following disclaimer. 131556Srgrimes * 2. Redistributions in binary form must reproduce the above copyright 141556Srgrimes * notice, this list of conditions and the following disclaimer in the 151556Srgrimes * documentation and/or other materials provided with the distribution. 161556Srgrimes * 4. Neither the name of the University nor the names of its contributors 171556Srgrimes * may be used to endorse or promote products derived from this software 181556Srgrimes * without specific prior written permission. 191556Srgrimes * 201556Srgrimes * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 211556Srgrimes * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 221556Srgrimes * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 231556Srgrimes * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 241556Srgrimes * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 251556Srgrimes * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 261556Srgrimes * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 271556Srgrimes * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 281556Srgrimes * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 291556Srgrimes * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 301556Srgrimes * SUCH DAMAGE. 311556Srgrimes */ 321556Srgrimes 331556Srgrimes#ifndef lint 3436150Scharnier#if 0 3536150Scharnierstatic char sccsid[] = "@(#)trap.c 8.5 (Berkeley) 6/5/95"; 3636150Scharnier#endif 371556Srgrimes#endif /* not lint */ 3899110Sobrien#include <sys/cdefs.h> 3999110Sobrien__FBSDID("$FreeBSD: head/bin/sh/trap.c 213811 2010-10-13 22:18:03Z obrien $"); 401556Srgrimes 4117987Speter#include <signal.h> 4217987Speter#include <unistd.h> 4317987Speter#include <stdlib.h> 4417987Speter 451556Srgrimes#include "shell.h" 461556Srgrimes#include "main.h" 471556Srgrimes#include "nodes.h" /* for other headers */ 481556Srgrimes#include "eval.h" 491556Srgrimes#include "jobs.h" 5017987Speter#include "show.h" 511556Srgrimes#include "options.h" 521556Srgrimes#include "syntax.h" 531556Srgrimes#include "output.h" 541556Srgrimes#include "memalloc.h" 551556Srgrimes#include "error.h" 561556Srgrimes#include "trap.h" 571556Srgrimes#include "mystring.h" 58100578Stjr#include "myhistedit.h" 591556Srgrimes 601556Srgrimes 611556Srgrimes/* 621556Srgrimes * Sigmode records the current value of the signal handlers for the various 631556Srgrimes * modes. A value of zero means that the current handler is not known. 641556Srgrimes * S_HARD_IGN indicates that the signal was ignored on entry to the shell, 651556Srgrimes */ 661556Srgrimes 671556Srgrimes#define S_DFL 1 /* default signal handling (SIG_DFL) */ 681556Srgrimes#define S_CATCH 2 /* signal is caught */ 691556Srgrimes#define S_IGN 3 /* signal is ignored (SIG_IGN) */ 7046684Skris#define S_HARD_IGN 4 /* signal is ignored permanently */ 711556Srgrimes#define S_RESET 5 /* temporary - to reset a hard ignored sig */ 721556Srgrimes 731556Srgrimes 7417987SpeterMKINIT char sigmode[NSIG]; /* current value of signal */ 7538521Scracauerint pendingsigs; /* indicates some signal received */ 7638536Scracauerint in_dotrap; /* do we execute in a trap handler? */ 7738950Scracauerstatic char *volatile trap[NSIG]; /* trap handler commands */ 78157811Sschweikhstatic volatile sig_atomic_t gotsig[NSIG]; 7938521Scracauer /* indicates specified signal received */ 8020902Sstevestatic int ignore_sigchld; /* Used while handling SIGCHLD traps. */ 81100588Stjrvolatile sig_atomic_t gotwinch; 821556Srgrimes 83213811Sobrienstatic int getsigaction(int, sig_t *); 8417987Speter 8520902Ssteve 861556Srgrimes/* 8720902Ssteve * Map a string to a signal number. 88125727Snjl * 89125727Snjl * Note: the signal number may exceed NSIG. 9020902Ssteve */ 91213811Sobrienstatic int 9290111Simpsigstring_to_signum(char *sig) 9320902Ssteve{ 9420902Ssteve 9520902Ssteve if (is_number(sig)) { 9620902Ssteve int signo; 9720902Ssteve 9820902Ssteve signo = atoi(sig); 9920902Ssteve return ((signo >= 0 && signo < NSIG) ? signo : (-1)); 10020902Ssteve } else if (strcasecmp(sig, "exit") == 0) { 10120902Ssteve return (0); 10220902Ssteve } else { 10320902Ssteve int n; 10420902Ssteve 10520902Ssteve if (strncasecmp(sig, "sig", 3) == 0) 10620902Ssteve sig += 3; 107125155Snjl for (n = 1; n < sys_nsig; n++) 108125728Snjl if (sys_signame[n] && 109125728Snjl strcasecmp(sys_signame[n], sig) == 0) 11020902Ssteve return (n); 11120902Ssteve } 11220902Ssteve return (-1); 11320902Ssteve} 11420902Ssteve 11520902Ssteve 11620902Ssteve/* 11720902Ssteve * Print a list of valid signal names. 11820902Ssteve */ 119213811Sobrienstatic void 12090111Simpprintsignals(void) 12120902Ssteve{ 122125727Snjl int n, outlen; 12320902Ssteve 124125727Snjl outlen = 0; 125125155Snjl for (n = 1; n < sys_nsig; n++) { 126125727Snjl if (sys_signame[n]) { 127125727Snjl out1fmt("%s", sys_signame[n]); 128125727Snjl outlen += strlen(sys_signame[n]); 129125727Snjl } else { 130125727Snjl out1fmt("%d", n); 131125727Snjl outlen += 3; /* good enough */ 132125727Snjl } 133125727Snjl ++outlen; 134125727Snjl if (outlen > 70 || n == sys_nsig - 1) { 13520902Ssteve out1str("\n"); 136125727Snjl outlen = 0; 137125727Snjl } else { 13820902Ssteve out1c(' '); 139125727Snjl } 14020902Ssteve } 14120902Ssteve} 14220902Ssteve 14320902Ssteve 14420902Ssteve/* 1451556Srgrimes * The trap builtin. 1461556Srgrimes */ 14717987Speterint 14890111Simptrapcmd(int argc, char **argv) 14917987Speter{ 1501556Srgrimes char *action; 1511556Srgrimes int signo; 152199641Sjilles int errors = 0; 1531556Srgrimes 1541556Srgrimes if (argc <= 1) { 155125155Snjl for (signo = 0 ; signo < sys_nsig ; signo++) { 156125727Snjl if (signo < NSIG && trap[signo] != NULL) { 157153244Sstefanf out1str("trap -- "); 158153244Sstefanf out1qstr(trap[signo]); 159125727Snjl if (signo == 0) { 160153244Sstefanf out1str(" exit\n"); 161125727Snjl } else if (sys_signame[signo]) { 162153244Sstefanf out1fmt(" %s\n", sys_signame[signo]); 163125727Snjl } else { 164153244Sstefanf out1fmt(" %d\n", signo); 165125727Snjl } 166125727Snjl } 1671556Srgrimes } 1681556Srgrimes return 0; 1691556Srgrimes } 17020902Ssteve action = NULL; 17120902Ssteve if (*++argv && strcmp(*argv, "--") == 0) 17220902Ssteve argv++; 17320902Ssteve if (*argv && sigstring_to_signum(*argv) == -1) { 17420902Ssteve if ((*argv)[0] != '-') { 17520902Ssteve action = *argv; 17620902Ssteve argv++; 17720902Ssteve } else if ((*argv)[1] == '\0') { 17820902Ssteve argv++; 17920902Ssteve } else if ((*argv)[1] == 'l' && (*argv)[2] == '\0') { 18020902Ssteve printsignals(); 18120902Ssteve return 0; 18220902Ssteve } else { 18320902Ssteve error("bad option %s", *argv); 18420902Ssteve } 18520902Ssteve } 18620902Ssteve while (*argv) { 187199641Sjilles if ((signo = sigstring_to_signum(*argv)) == -1) { 188199641Sjilles out2fmt_flush("trap: bad signal %s\n", *argv); 189199641Sjilles errors = 1; 190199641Sjilles } 1911556Srgrimes INTOFF; 1921556Srgrimes if (action) 1931556Srgrimes action = savestr(action); 1941556Srgrimes if (trap[signo]) 1951556Srgrimes ckfree(trap[signo]); 1961556Srgrimes trap[signo] = action; 1971556Srgrimes if (signo != 0) 1981556Srgrimes setsignal(signo); 1991556Srgrimes INTON; 20020902Ssteve argv++; 2011556Srgrimes } 202199641Sjilles return errors; 2031556Srgrimes} 2041556Srgrimes 2051556Srgrimes 2061556Srgrimes/* 2071556Srgrimes * Clear traps on a fork. 2081556Srgrimes */ 2091556Srgrimesvoid 21090111Simpclear_traps(void) 21120902Ssteve{ 21238950Scracauer char *volatile *tp; 2131556Srgrimes 21420902Ssteve for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) { 2151556Srgrimes if (*tp && **tp) { /* trap not NULL or SIG_IGN */ 2161556Srgrimes INTOFF; 2171556Srgrimes ckfree(*tp); 2181556Srgrimes *tp = NULL; 2191556Srgrimes if (tp != &trap[0]) 2201556Srgrimes setsignal(tp - trap); 2211556Srgrimes INTON; 2221556Srgrimes } 2231556Srgrimes } 2241556Srgrimes} 2251556Srgrimes 2261556Srgrimes 2271556Srgrimes/* 228194127Sjilles * Check if we have any traps enabled. 229194127Sjilles */ 230194127Sjillesint 231194127Sjilleshave_traps(void) 232194127Sjilles{ 233194127Sjilles char *volatile *tp; 234194127Sjilles 235194127Sjilles for (tp = trap ; tp <= &trap[NSIG - 1] ; tp++) { 236194127Sjilles if (*tp && **tp) /* trap not NULL or SIG_IGN */ 237194127Sjilles return 1; 238194127Sjilles } 239194127Sjilles return 0; 240194127Sjilles} 241194127Sjilles 242194127Sjilles/* 2431556Srgrimes * Set the signal handler for the specified signal. The routine figures 2441556Srgrimes * out what it should be set to. 2451556Srgrimes */ 24631098Sbdevoid 24790111Simpsetsignal(int signo) 24817987Speter{ 2491556Srgrimes int action; 250199205Sjilles sig_t sigact = SIG_DFL; 251199205Sjilles struct sigaction sa; 2521556Srgrimes char *t; 2531556Srgrimes 2541556Srgrimes if ((t = trap[signo]) == NULL) 2551556Srgrimes action = S_DFL; 2561556Srgrimes else if (*t != '\0') 2571556Srgrimes action = S_CATCH; 2581556Srgrimes else 2591556Srgrimes action = S_IGN; 26038521Scracauer if (action == S_DFL) { 2611556Srgrimes switch (signo) { 2621556Srgrimes case SIGINT: 26338521Scracauer action = S_CATCH; 2641556Srgrimes break; 2651556Srgrimes case SIGQUIT: 2661556Srgrimes#ifdef DEBUG 2671556Srgrimes { 2681556Srgrimes extern int debug; 2691556Srgrimes 2701556Srgrimes if (debug) 2711556Srgrimes break; 2721556Srgrimes } 2731556Srgrimes#endif 27438535Scracauer action = S_CATCH; 27538521Scracauer break; 2761556Srgrimes case SIGTERM: 27738521Scracauer if (rootshell && iflag) 2781556Srgrimes action = S_IGN; 2791556Srgrimes break; 2801556Srgrimes#if JOBS 2811556Srgrimes case SIGTSTP: 2821556Srgrimes case SIGTTOU: 28338521Scracauer if (rootshell && mflag) 2841556Srgrimes action = S_IGN; 2851556Srgrimes break; 2861556Srgrimes#endif 287100578Stjr#ifndef NO_HISTORY 288100578Stjr case SIGWINCH: 289100588Stjr if (rootshell && iflag) 290100578Stjr action = S_CATCH; 291100578Stjr break; 292100578Stjr#endif 2931556Srgrimes } 2941556Srgrimes } 29517987Speter 29620902Ssteve t = &sigmode[signo]; 2978855Srgrimes if (*t == 0) { 2988855Srgrimes /* 2998855Srgrimes * current setting unknown 3001556Srgrimes */ 30117987Speter if (!getsigaction(signo, &sigact)) { 30217987Speter /* 30317987Speter * Pretend it worked; maybe we should give a warning 30417987Speter * here, but other shells don't. We don't alter 30517987Speter * sigmode, so that we retry every time. 30617987Speter */ 30731098Sbde return; 30817987Speter } 3091556Srgrimes if (sigact == SIG_IGN) { 3108855Srgrimes if (mflag && (signo == SIGTSTP || 3111556Srgrimes signo == SIGTTIN || signo == SIGTTOU)) { 3121556Srgrimes *t = S_IGN; /* don't hard ignore these */ 3131556Srgrimes } else 3141556Srgrimes *t = S_HARD_IGN; 3151556Srgrimes } else { 3161556Srgrimes *t = S_RESET; /* force to be set */ 3171556Srgrimes } 3181556Srgrimes } 3191556Srgrimes if (*t == S_HARD_IGN || *t == action) 32031098Sbde return; 3211556Srgrimes switch (action) { 3221556Srgrimes case S_DFL: sigact = SIG_DFL; break; 3231556Srgrimes case S_CATCH: sigact = onsig; break; 3241556Srgrimes case S_IGN: sigact = SIG_IGN; break; 3251556Srgrimes } 3261556Srgrimes *t = action; 327199205Sjilles sa.sa_handler = sigact; 328199205Sjilles sa.sa_flags = 0; 329199205Sjilles sigemptyset(&sa.sa_mask); 330199205Sjilles sigaction(signo, &sa, NULL); 3311556Srgrimes} 3321556Srgrimes 33320902Ssteve 3341556Srgrimes/* 3351556Srgrimes * Return the current setting for sig w/o changing it. 3361556Srgrimes */ 337213811Sobrienstatic int 33890111Simpgetsigaction(int signo, sig_t *sigact) 33917987Speter{ 3401556Srgrimes struct sigaction sa; 3411556Srgrimes 3421556Srgrimes if (sigaction(signo, (struct sigaction *)0, &sa) == -1) 34317987Speter return 0; 34417987Speter *sigact = (sig_t) sa.sa_handler; 34517987Speter return 1; 3461556Srgrimes} 3471556Srgrimes 34820902Ssteve 3491556Srgrimes/* 3501556Srgrimes * Ignore a signal. 3511556Srgrimes */ 3521556Srgrimesvoid 35390111Simpignoresig(int signo) 35417987Speter{ 35520902Ssteve 35620902Ssteve if (sigmode[signo] != S_IGN && sigmode[signo] != S_HARD_IGN) { 3571556Srgrimes signal(signo, SIG_IGN); 3581556Srgrimes } 35920902Ssteve sigmode[signo] = S_HARD_IGN; 3601556Srgrimes} 3611556Srgrimes 3621556Srgrimes 3631556Srgrimes#ifdef mkinit 36417987SpeterINCLUDE <signal.h> 3651556SrgrimesINCLUDE "trap.h" 3661556Srgrimes 3671556SrgrimesSHELLPROC { 3681556Srgrimes char *sm; 3691556Srgrimes 3701556Srgrimes clear_traps(); 37117987Speter for (sm = sigmode ; sm < sigmode + NSIG ; sm++) { 3721556Srgrimes if (*sm == S_IGN) 3731556Srgrimes *sm = S_HARD_IGN; 3741556Srgrimes } 3751556Srgrimes} 3761556Srgrimes#endif 3771556Srgrimes 3781556Srgrimes 3791556Srgrimes/* 3801556Srgrimes * Signal handler. 3811556Srgrimes */ 3821556Srgrimesvoid 38390111Simponsig(int signo) 38417987Speter{ 38531098Sbde 3861556Srgrimes if (signo == SIGINT && trap[SIGINT] == NULL) { 3871556Srgrimes onint(); 3881556Srgrimes return; 3891556Srgrimes } 39038950Scracauer 39120902Ssteve if (signo != SIGCHLD || !ignore_sigchld) 39220902Ssteve gotsig[signo] = 1; 3931556Srgrimes pendingsigs++; 39438950Scracauer 39538950Scracauer /* If we are currently in a wait builtin, prepare to break it */ 39638950Scracauer if ((signo == SIGINT || signo == SIGQUIT) && in_waitcmd != 0) 39738521Scracauer breakwaitcmd = 1; 398157811Sschweikh /* 399157811Sschweikh * If a trap is set, not ignored and not the null command, we need 40039056Scracauer * to make sure traps are executed even when a child blocks signals. 40138950Scracauer */ 40245221Scracauer if (Tflag && 403157811Sschweikh trap[signo] != NULL && 404149825Srse ! (trap[signo][0] == '\0') && 40539049Scracauer ! (trap[signo][0] == ':' && trap[signo][1] == '\0')) 40639049Scracauer breakwaitcmd = 1; 407100578Stjr 408100578Stjr#ifndef NO_HISTORY 409100578Stjr if (signo == SIGWINCH) 410100588Stjr gotwinch = 1; 411100578Stjr#endif 4121556Srgrimes} 4131556Srgrimes 4141556Srgrimes 4151556Srgrimes/* 4161556Srgrimes * Called to execute a trap. Perhaps we should avoid entering new trap 4171556Srgrimes * handlers while we are executing a trap handler. 4181556Srgrimes */ 4191556Srgrimesvoid 42090111Simpdotrap(void) 42120902Ssteve{ 4221556Srgrimes int i; 4231556Srgrimes int savestatus; 4241556Srgrimes 42538521Scracauer in_dotrap++; 4261556Srgrimes for (;;) { 42720902Ssteve for (i = 1; i < NSIG; i++) { 42820902Ssteve if (gotsig[i]) { 42920902Ssteve gotsig[i] = 0; 43020902Ssteve if (trap[i]) { 43120902Ssteve /* 432125728Snjl * Ignore SIGCHLD to avoid infinite 433125728Snjl * recursion if the trap action does 434125728Snjl * a fork. 43520902Ssteve */ 43620902Ssteve if (i == SIGCHLD) 43720902Ssteve ignore_sigchld++; 43820902Ssteve savestatus = exitstatus; 439193169Sstefanf evalstring(trap[i], 0); 44020902Ssteve exitstatus = savestatus; 44120902Ssteve if (i == SIGCHLD) 44220902Ssteve ignore_sigchld--; 44320902Ssteve } 4441556Srgrimes break; 44520902Ssteve } 4461556Srgrimes } 44720902Ssteve if (i >= NSIG) 44820902Ssteve break; 4491556Srgrimes } 45038521Scracauer in_dotrap--; 4511556Srgrimes pendingsigs = 0; 4521556Srgrimes} 4531556Srgrimes 4541556Srgrimes 4551556Srgrimes/* 4561556Srgrimes * Controls whether the shell is interactive or not. 4571556Srgrimes */ 4581556Srgrimesvoid 45990111Simpsetinteractive(int on) 46017987Speter{ 46138521Scracauer static int is_interactive = -1; 4621556Srgrimes 4631556Srgrimes if (on == is_interactive) 4641556Srgrimes return; 4651556Srgrimes setsignal(SIGINT); 4661556Srgrimes setsignal(SIGQUIT); 4671556Srgrimes setsignal(SIGTERM); 468100578Stjr#ifndef NO_HISTORY 469100578Stjr setsignal(SIGWINCH); 470100578Stjr#endif 4711556Srgrimes is_interactive = on; 4721556Srgrimes} 4731556Srgrimes 4741556Srgrimes 4751556Srgrimes/* 4761556Srgrimes * Called to exit the shell. 4771556Srgrimes */ 4781556Srgrimesvoid 47990111Simpexitshell(int status) 48017987Speter{ 4811556Srgrimes struct jmploc loc1, loc2; 4821556Srgrimes char *p; 4831556Srgrimes 4841556Srgrimes TRACE(("exitshell(%d) pid=%d\n", status, getpid())); 4851556Srgrimes if (setjmp(loc1.loc)) { 4861556Srgrimes goto l1; 4871556Srgrimes } 4881556Srgrimes if (setjmp(loc2.loc)) { 4891556Srgrimes goto l2; 4901556Srgrimes } 4911556Srgrimes handler = &loc1; 4921556Srgrimes if ((p = trap[0]) != NULL && *p != '\0') { 4931556Srgrimes trap[0] = NULL; 494193169Sstefanf evalstring(p, 0); 4951556Srgrimes } 4961556Srgrimesl1: handler = &loc2; /* probably unnecessary */ 4971556Srgrimes flushall(); 4981556Srgrimes#if JOBS 4991556Srgrimes setjobctl(0); 5001556Srgrimes#endif 5011556Srgrimesl2: _exit(status); 5021556Srgrimes} 503