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      1 /*
      2  * CDDL HEADER START
      3  *
      4  * The contents of this file are subject to the terms of the
      5  * Common Development and Distribution License, Version 1.0 only
      6  * (the "License").  You may not use this file except in compliance
      7  * with the License.
      8  *
      9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
     10  * or http://www.opensolaris.org/os/licensing.
     11  * See the License for the specific language governing permissions
     12  * and limitations under the License.
     13  *
     14  * When distributing Covered Code, include this CDDL HEADER in each
     15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
     16  * If applicable, add the following below this CDDL HEADER, with the
     17  * fields enclosed by brackets "[]" replaced with your own identifying
     18  * information: Portions Copyright [yyyy] [name of copyright owner]
     19  *
     20  * CDDL HEADER END
     21  */
     22 /*	Copyright (c) 1988 AT&T	*/
     23 /*	  All Rights Reserved  	*/
     24 
     25 
     26 /*
     27  * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
     28  * Use is subject to license terms.
     29  */
     30 
     31 #pragma ident	"%Z%%M%	%I%	%E% SMI"
     32 
     33 /*
     34  *	cscope - interactive C symbol cross-reference
     35  *
     36  *	process execution functions
     37  */
     38 
     39 #include "global.h"
     40 #include <sys/types.h>
     41 #include <sys/wait.h>
     42 #include <stdarg.h>
     43 #include <unistd.h>
     44 #include <stdlib.h>
     45 #include <stdio.h>
     46 #include <libgen.h>
     47 
     48 #define	getdtablesize()	_NFILE
     49 
     50 #define	MAXARGS	100	/* maximum number of arguments to executed command */
     51 
     52 pid_t	childpid;	/* child's process ID */
     53 
     54 static	SIGTYPE	(*oldsigquit)();	/* old value of quit signal */
     55 static	SIGTYPE	(*oldsigtstp)();	/* old value of terminal stop signal */
     56 
     57 static pid_t myfork(void);
     58 static int join(pid_t p);
     59 
     60 /*
     61  * execute forks and executes a program or shell script, waits for it to
     62  * finish, and returns its exit code.
     63  */
     64 
     65 /*VARARGS0*/
     66 int
     67 execute(char *path, ...)
     68 {
     69 	va_list	ap;
     70 	char	*args[MAXARGS + 1];
     71 	int	exitcode;
     72 	int	i;
     73 	char	msg[MSGLEN + 1];
     74 	pid_t	p;
     75 
     76 	/* fork and exec the program or shell script */
     77 	exitcurses();
     78 	if ((p = myfork()) == 0) {
     79 
     80 		/* close all files except stdin, stdout, and stderr */
     81 		for (i = 3; i < getdtablesize() && close(i) == 0; ++i) {
     82 			;
     83 		}
     84 		/* execute the program or shell script */
     85 		va_start(ap, path);
     86 		for (i = 0; i < MAXARGS &&
     87 		    (args[i] = va_arg(ap, char *)) != NULL; ++i) {
     88 		}
     89 		va_end(ap);
     90 		args[i] = NULL;			/* in case MAXARGS reached */
     91 		args[0] = basename(args[0]);
     92 		(void) execvp(path, args);	/* returns only on failure */
     93 		(void) sprintf(msg, "\ncscope: cannot execute %s", path);
     94 		(void) perror(msg);	/* display the reason */
     95 		askforreturn();	 /* wait until the user sees the message */
     96 		exit(1);		/* exit the child */
     97 	} else {
     98 		exitcode = join(p);	/* parent */
     99 	}
    100 	if (noacttimeout) {
    101 		(void) fprintf(stderr,
    102 		    "cscope: no activity time out--exiting\n");
    103 		myexit(SIGALRM);
    104 	}
    105 	entercurses();
    106 	return (exitcode);
    107 }
    108 
    109 /* myfork acts like fork but also handles signals */
    110 
    111 static pid_t
    112 myfork(void)
    113 {
    114 	pid_t	p;		/* process number */
    115 
    116 	oldsigtstp = signal(SIGTSTP, SIG_DFL);
    117 	/* the parent ignores the interrupt and quit signals */
    118 	if ((p = fork()) > 0) {
    119 		childpid = p;
    120 		oldsigquit = signal(SIGQUIT, SIG_IGN);
    121 	}
    122 	/* so they can be used to stop the child */
    123 	else if (p == 0) {
    124 		(void) signal(SIGINT, SIG_DFL);
    125 		(void) signal(SIGQUIT, SIG_DFL);
    126 		(void) signal(SIGHUP, SIG_DFL);	/* restore hangup default */
    127 	}
    128 	/* check for fork failure */
    129 	if (p == -1) {
    130 		myperror("Cannot fork");
    131 	}
    132 	return (p);
    133 }
    134 
    135 /* join is the compliment of fork */
    136 
    137 static int
    138 join(pid_t p)
    139 {
    140 	int	status;
    141 	pid_t	w;
    142 
    143 	/* wait for the correct child to exit */
    144 	do {
    145 		w = wait(&status);
    146 	} while (p != -1 && w != p);
    147 	childpid = 0;
    148 
    149 	/* restore signal handling */
    150 	(void) signal(SIGQUIT, oldsigquit);
    151 	(void) signal(SIGTSTP, oldsigtstp);
    152 	/* return the child's exit code */
    153 	return (status >> 8);
    154 }
    155