xref: /titanic_52/usr/src/tools/cscope-fast/exec.c (revision 18c2aff776a775d34a4c9893a4c72e0434d68e36)
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