/*- * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * Copyright (c) 1997-2005 * Herbert Xu . 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 #include #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" #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 */ char *trap[NSIG]; /* current value of signal */ static char sigmode[NSIG - 1]; /* indicates specified signal received */ char gotsig[NSIG - 1]; /* last pending signal */ volatile sig_atomic_t pendingsigs; /* do we generate EXSIG events */ int exsig; #ifdef mkinit INCLUDE INIT { signal(SIGCHLD, SIG_DFL); } #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) sh_error("%s: bad trap", *ap); INTOFF; if (action) { if (action[0] == '-' && action[1] == '\0') action = NULL; else action = savestr(action); } if (trap[signo]) 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; for (tp = trap ; tp < &trap[NSIG] ; tp++) { if (*tp && **tp) { /* trap not NULL or SIG_IGN */ INTOFF; ckfree(*tp); *tp = NULL; if (tp != &trap[0]) setsignal(tp - trap); 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 } } 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) { gotsig[signo - 1] = 1; pendingsigs = signo; if (exsig || (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. */ int 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, SKIPEVAL); exitstatus = savestatus; if (evalskip) return evalskip; } return 0; } /* * 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; 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) _exit(exitstatus); goto out; } handler = &loc; if ((p = trap[0])) { trap[0] = NULL; evalstring(p, 0); } flushall(); out: _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; } }