/* $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 #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 #include #include #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" /* * 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 (sys_signame[i] && (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 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 */ }