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Diffstat (limited to '')
| -rw-r--r-- | usr/dash/trap.c | 467 |
1 files changed, 467 insertions, 0 deletions
diff --git a/usr/dash/trap.c b/usr/dash/trap.c new file mode 100644 index 0000000..1e2a867 --- /dev/null +++ b/usr/dash/trap.c @@ -0,0 +1,467 @@ +/*- + * Copyright (c) 1991, 1993 + * The Regents of the University of California. All rights reserved. + * Copyright (c) 1997-2005 + * Herbert Xu <herbert@gondor.apana.org.au>. 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 <signal.h> +#include <unistd.h> +#include <stdlib.h> +#include <string.h> +#include <stdio.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" + +#ifdef HETIO +#include "hetio.h" +#endif + +/* + * 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 */ + + +/* trap handler commands */ +static char *trap[NSIG]; +/* number of non-null traps */ +int trapcnt; +/* current value of signal */ +char sigmode[NSIG - 1]; +/* indicates specified signal received */ +static char gotsig[NSIG - 1]; +/* last pending signal */ +volatile sig_atomic_t pendingsigs; +/* received SIGCHLD */ +int gotsigchld; + +#ifdef mkinit +INCLUDE "trap.h" +INIT { + sigmode[SIGCHLD - 1] = S_DFL; + setsignal(SIGCHLD); +} +#endif + +/* + * The trap builtin. + */ + +int +trapcmd(int argc, char **argv) +{ + char *action; + char **ap; + int signo; + + nextopt(nullstr); + ap = argptr; + if (!*ap) { + for (signo = 0 ; signo < NSIG ; signo++) { + if (trap[signo] != NULL) { + out1fmt( + "trap -- %s %s\n", + single_quote(trap[signo]), + signal_name(signo) + ); + } + } + return 0; + } + if (!ap[1]) + action = NULL; + else + action = *ap++; + while (*ap) { + if ((signo = decode_signal(*ap, 0)) < 0) { + outfmt(out2, "trap: %s: bad trap\n", *ap); + return 1; + } + INTOFF; + if (action) { + if (action[0] == '-' && action[1] == '\0') + action = NULL; + else { + if (*action) + trapcnt++; + action = savestr(action); + } + } + if (trap[signo]) { + if (*trap[signo]) + trapcnt--; + ckfree(trap[signo]); + } + trap[signo] = action; + if (signo != 0) + setsignal(signo); + INTON; + ap++; + } + return 0; +} + + + +/* + * Clear traps on a fork. + */ + +void +clear_traps(void) +{ + char **tp; + + INTOFF; + for (tp = trap ; tp < &trap[NSIG] ; tp++) { + if (*tp && **tp) { /* trap not NULL or SIG_IGN */ + ckfree(*tp); + *tp = NULL; + if (tp != &trap[0]) + setsignal(tp - trap); + } + } + trapcnt = 0; + INTON; +} + + + +/* + * Set the signal handler for the specified signal. The routine figures + * out what it should be set to. + */ + +void +setsignal(int signo) +{ + int action; + char *t, tsig; + struct sigaction act; + + if ((t = trap[signo]) == NULL) + action = S_DFL; + else if (*t != '\0') + action = S_CATCH; + else + action = S_IGN; + if (rootshell && 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 + } + } + + if (signo == SIGCHLD) + action = S_CATCH; + + t = &sigmode[signo - 1]; + tsig = *t; + if (tsig == 0) { + /* + * current setting unknown + */ + if (sigaction(signo, 0, &act) == -1) { + /* + * 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; + } + if (act.sa_handler == 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; + switch (action) { + case S_CATCH: + act.sa_handler = onsig; + break; + case S_IGN: + act.sa_handler = SIG_IGN; + break; + default: + act.sa_handler = SIG_DFL; + } + *t = action; + act.sa_flags = 0; + sigfillset(&act.sa_mask); + sigaction(signo, &act, 0); +} + +/* + * Ignore a signal. + */ + +void +ignoresig(int signo) +{ + if (sigmode[signo - 1] != S_IGN && sigmode[signo - 1] != S_HARD_IGN) { + signal(signo, SIG_IGN); + } + sigmode[signo - 1] = S_HARD_IGN; +} + + + +/* + * Signal handler. + */ + +void +onsig(int signo) +{ + if (signo == SIGCHLD) { + gotsigchld = 1; + if (!trap[SIGCHLD]) + return; + } + + gotsig[signo - 1] = 1; + pendingsigs = signo; + + if (signo == SIGINT && !trap[SIGINT]) { + if (!suppressint) + onint(); + intpending = 1; + } +} + + + +/* + * Called to execute a trap. Perhaps we should avoid entering new trap + * handlers while we are executing a trap handler. + */ + +void dotrap(void) +{ + char *p; + char *q; + int i; + int savestatus; + + savestatus = exitstatus; + pendingsigs = 0; + barrier(); + + for (i = 0, q = gotsig; i < NSIG - 1; i++, q++) { + if (!*q) + continue; + *q = 0; + + p = trap[i + 1]; + if (!p) + continue; + evalstring(p, 0); + exitstatus = savestatus; + if (evalskip) + break; + } +} + + + +/* + * Controls whether the shell is interactive or not. + */ + + +void +setinteractive(int on) +{ + static int is_interactive; + + if (++on == is_interactive) + return; + is_interactive = on; + setsignal(SIGINT); + setsignal(SIGQUIT); + setsignal(SIGTERM); +} + + + +/* + * Called to exit the shell. + */ + +void +exitshell(void) +{ + struct jmploc loc; + char *p; + volatile int status; + +#ifdef HETIO + hetio_reset_term(); +#endif + status = exitstatus; + TRACE(("pid %d, exitshell(%d)\n", getpid(), status)); + if (setjmp(loc.loc)) { + if (exception == EXEXIT) + status = exitstatus; + goto out; + } + handler = &loc; + if ((p = trap[0])) { + trap[0] = NULL; + evalskip = 0; + evalstring(p, 0); + } +out: + /* + * Disable job control so that whoever had the foreground before we + * started can get it back. + */ + if (likely(!setjmp(loc.loc))) + setjobctl(0); + flushall(); + _exit(status); + /* NOTREACHED */ +} + +/* + * Decode a signal name + */ +int decode_signal(const char *string, int minsig) +{ + int i; + + if (is_number(string)) { + i = atoi(string); + if (i >= NSIG) { + return -1; + } + return i; + } + + for ( i = minsig ; i < NSIG ; i++ ) { + if ( sys_sigabbrev[i] && + !strcasecmp(string, sys_sigabbrev[i]) ) + return i; + } + +#ifdef SIGRTMIN + if ( !strncasecmp(string, "RTMIN", 5) ) { + char *ep; + + if ( string[5] && string[5] != '+' ) + return -1; + i = SIGRTMIN + strtol(string+5, &ep, 10); + if ( *ep || i < SIGRTMIN || i > SIGRTMAX ) + return -1; + return i; + } + + if ( !strncasecmp(string, "RTMAX", 5) ) { + char *ep; + + if ( string[5] && string[5] != '-' ) + return -1; + i = SIGRTMAX + strtol(string+5, &ep, 10); + if ( *ep || i < SIGRTMIN || i > SIGRTMAX ) + return -1; + return i; + } +#endif + + return -1; +} + +/* + * Human-readable signal name + */ +const char * +signal_name(int sig) +{ + static char buf[64]; + + if ( sig < 0 || sig >= NSIG ) { + return NULL; + } else if ( sys_sigabbrev[sig] ) { + return sys_sigabbrev[sig]; +#ifdef SIGRTMIN + } else if ( sig >= SIGRTMIN && sig <= SIGRTMAX ) { + snprintf(buf, sizeof buf, "RTMIN+%d", sig-SIGRTMIN); + return buf; +#endif + } else { + snprintf(buf, sizeof buf, "%d", sig); + return buf; + } +} |