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Diffstat (limited to 'sh/trap.c')
| -rw-r--r-- | sh/trap.c | 470 |
1 files changed, 470 insertions, 0 deletions
diff --git a/sh/trap.c b/sh/trap.c new file mode 100644 index 0000000..b3b2db4 --- /dev/null +++ b/sh/trap.c @@ -0,0 +1,470 @@ +/* $NetBSD: trap.c,v 1.31 2005/01/11 19:38:57 christos Exp $ */ + +/*- + * Copyright (c) 1991, 1993 + * The Regents of the University of California. All rights reserved. + * + * This code is derived from software contributed to Berkeley by + * Kenneth Almquist. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in the + * documentation and/or other materials provided with the distribution. + * 3. Neither the name of the University nor the names of its contributors + * may be used to endorse or promote products derived from this software + * without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND + * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE + * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE + * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE + * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL + * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS + * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) + * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT + * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY + * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF + * SUCH DAMAGE. + */ + +#include <sys/cdefs.h> +#ifndef lint +#if 0 +static char sccsid[] = "@(#)trap.c 8.5 (Berkeley) 6/5/95"; +#else +__RCSID("$NetBSD: trap.c,v 1.31 2005/01/11 19:38:57 christos Exp $"); +#endif +#endif /* not lint */ + +#include <signal.h> +#include <unistd.h> +#include <stdlib.h> + +#include "shell.h" +#include "main.h" +#include "nodes.h" /* for other headers */ +#include "eval.h" +#include "jobs.h" +#include "show.h" +#include "options.h" +#include "syntax.h" +#include "output.h" +#include "memalloc.h" +#include "error.h" +#include "trap.h" +#include "mystring.h" +#include "var.h" + +static const char *sys_signame[NSIG] = { + "Unused", + "HUP", "INT", "QUIT", "ILL", + "TRAP", "ABRT", "BUS", "FPE", + "KILL", "USR1", "SEGV", "USR2", + "PIPE", "ALRM", "TERM", + "Unknown", + "CHLD", + "CONT", "STOP", "TSTP", "TTIN", + "TTOU", "URG", "XCPU", "XFSZ", + "VTALRM", "PROF", "WINCH", "IO", + "PWR", "SYS" +}; + +/* + * Sigmode records the current value of the signal handlers for the various + * modes. A value of zero means that the current handler is not known. + * S_HARD_IGN indicates that the signal was ignored on entry to the shell, + */ + +#define S_DFL 1 /* default signal handling (SIG_DFL) */ +#define S_CATCH 2 /* signal is caught */ +#define S_IGN 3 /* signal is ignored (SIG_IGN) */ +#define S_HARD_IGN 4 /* signal is ignored permenantly */ +#define S_RESET 5 /* temporary - to reset a hard ignored sig */ + + +char *trap[NSIG+1]; /* trap handler commands */ +MKINIT char sigmode[NSIG]; /* current value of signal */ +char gotsig[NSIG]; /* indicates specified signal received */ +int pendingsigs; /* indicates some signal received */ + +static int getsigaction(int, sig_t *); + +/* + * return the signal number described by `p' (as a number or a name) + * or -1 if it isn't one + */ + +static int +signame_to_signum(const char *p) +{ + int i; + + if (is_number(p)) + return number(p); + + if (strcasecmp(p, "exit") == 0 ) + return 0; + + if (strncasecmp(p, "sig", 3) == 0) + p += 3; + + for (i = 0; i < NSIG; ++i) + if (strcasecmp (p, sys_signame[i]) == 0) + return i; + return -1; +} + +/* + * Print a list of valid signal names + */ +static void +printsignals(void) +{ + int n; + + out1str("EXIT "); + + for (n = 1; n < NSIG; n++) { + out1fmt("%s", sys_signame[n]); + if ((n == NSIG/2) || n == (NSIG - 1)) + out1str("\n"); + else + out1c(' '); + } +} + +/* + * The trap builtin. + */ + +int +trapcmd(int argc, char **argv) +{ + char *action; + char **ap; + int signo; + + if (argc <= 1) { + for (signo = 0 ; signo <= NSIG ; signo++) + if (trap[signo] != NULL) { + out1fmt("trap -- "); + print_quoted(trap[signo]); + out1fmt(" %s\n", + (signo) ? sys_signame[signo] : "EXIT"); + } + return 0; + } + ap = argv + 1; + + action = NULL; + + if (strcmp(*ap, "--") == 0) + if (*++ap == NULL) + return 0; + + if (signame_to_signum(*ap) == -1) { + if ((*ap)[0] == '-') { + if ((*ap)[1] == '\0') + ap++; + else if ((*ap)[1] == 'l' && (*ap)[2] == '\0') { + printsignals(); + return 0; + } + else + error("bad option %s\n", *ap); + } + else + action = *ap++; + } + + while (*ap) { + if (is_number(*ap)) + signo = number(*ap); + else + signo = signame_to_signum(*ap); + + if (signo < 0 || signo > NSIG) + error("%s: bad trap", *ap); + + INTOFF; + if (action) + action = savestr(action); + + if (trap[signo]) + ckfree(trap[signo]); + + trap[signo] = action; + + if (signo != 0) + setsignal(signo, 0); + INTON; + ap++; + } + return 0; +} + + + +/* + * Clear traps on a fork or vfork. + * Takes one arg vfork, to tell it to not be destructive of + * the parents variables. + */ + +void +clear_traps(int vforked) +{ + char **tp; + + for (tp = trap ; tp <= &trap[NSIG] ; tp++) { + if (*tp && **tp) { /* trap not NULL or SIG_IGN */ + INTOFF; + if (!vforked) { + ckfree(*tp); + *tp = NULL; + } + if (tp != &trap[0]) + setsignal(tp - trap, vforked); + INTON; + } + } +} + + + +/* + * Set the signal handler for the specified signal. The routine figures + * out what it should be set to. + */ + +long +setsignal(int signo, int vforked) +{ + int action; + sig_t sigact = SIG_DFL; + struct sigaction act, oact; + char *t, tsig; + + if ((t = trap[signo]) == NULL) + action = S_DFL; + else if (*t != '\0') + action = S_CATCH; + else + action = S_IGN; + if (rootshell && !vforked && action == S_DFL) { + switch (signo) { + case SIGINT: + if (iflag || minusc || sflag == 0) + action = S_CATCH; + break; + case SIGQUIT: +#ifdef DEBUG + if (debug) + break; +#endif + /* FALLTHROUGH */ + case SIGTERM: + if (iflag) + action = S_IGN; + break; +#if JOBS + case SIGTSTP: + case SIGTTOU: + if (mflag) + action = S_IGN; + break; +#endif + } + } + + t = &sigmode[signo - 1]; + tsig = *t; + if (tsig == 0) { + /* + * current setting unknown + */ + if (!getsigaction(signo, &sigact)) { + /* + * Pretend it worked; maybe we should give a warning + * here, but other shells don't. We don't alter + * sigmode, so that we retry every time. + */ + return 0; + } + if (sigact == SIG_IGN) { + if (mflag && (signo == SIGTSTP || + signo == SIGTTIN || signo == SIGTTOU)) { + tsig = S_IGN; /* don't hard ignore these */ + } else + tsig = S_HARD_IGN; + } else { + tsig = S_RESET; /* force to be set */ + } + } + if (tsig == S_HARD_IGN || tsig == action) + return 0; + switch (action) { + case S_DFL: sigact = SIG_DFL; break; + case S_CATCH: sigact = onsig; break; + case S_IGN: sigact = SIG_IGN; break; + } + if (!vforked) + *t = action; + act.sa_handler = sigact; + sigemptyset(&act.sa_mask); + act.sa_flags = 0; +#ifdef SA_INTERRUPT + act.sa_flags |= SA_INTERRUPT; +#endif + if(sigaction(signo, &act, &oact) < 0) + return (long) SIG_ERR; + return (long) oact.sa_handler; +} + +/* + * Return the current setting for sig w/o changing it. + */ +static int +getsigaction(int signo, sig_t *sigact) +{ + struct sigaction sa; + + if (sigaction(signo, (struct sigaction *)0, &sa) == -1) + return 0; + *sigact = (sig_t) sa.sa_handler; + return 1; +} + +/* + * Ignore a signal. + */ + +void +ignoresig(int signo, int vforked) +{ + if (sigmode[signo - 1] != S_IGN && sigmode[signo - 1] != S_HARD_IGN) + bsd_signal(signo, SIG_IGN); + if (!vforked) + sigmode[signo - 1] = S_HARD_IGN; +} + + +#ifdef mkinit +INCLUDE <signal.h> +INCLUDE "trap.h" + +SHELLPROC { + char *sm; + + clear_traps(0); + for (sm = sigmode ; sm < sigmode + NSIG ; sm++) { + if (*sm == S_IGN) + *sm = S_HARD_IGN; + } +} +#endif + + + +/* + * Signal handler. + */ + +void +onsig(int signo) +{ + bsd_signal(signo, onsig); + if (signo == SIGINT && trap[SIGINT] == NULL) { + onint(); + return; + } + gotsig[signo - 1] = 1; + pendingsigs++; +} + + + +/* + * Called to execute a trap. Perhaps we should avoid entering new trap + * handlers while we are executing a trap handler. + */ + +void +dotrap(void) +{ + int i; + int savestatus; + + for (;;) { + for (i = 1 ; ; i++) { + if (gotsig[i - 1]) + break; + if (i >= NSIG) + goto done; + } + gotsig[i - 1] = 0; + savestatus=exitstatus; + evalstring(trap[i], 0); + exitstatus=savestatus; + } +done: + pendingsigs = 0; +} + + + +/* + * Controls whether the shell is interactive or not. + */ + + +void +setinteractive(int on) +{ + static int is_interactive; + + if (on == is_interactive) + return; + setsignal(SIGINT, 0); + setsignal(SIGQUIT, 0); + setsignal(SIGTERM, 0); + is_interactive = on; +} + + + +/* + * Called to exit the shell. + */ + +void +exitshell(int status) +{ + struct jmploc loc1, loc2; + char *p; + + TRACE(("pid %d, exitshell(%d)\n", getpid(), status)); + if (setjmp(loc1.loc)) { + goto l1; + } + if (setjmp(loc2.loc)) { + goto l2; + } + handler = &loc1; + if ((p = trap[0]) != NULL && *p != '\0') { + trap[0] = NULL; + evalstring(p, 0); + } +l1: handler = &loc2; /* probably unnecessary */ + flushall(); +#if JOBS + setjobctl(0); +#endif +l2: _exit(status); + /* NOTREACHED */ +} |