xref: /illumos-gate/usr/src/cmd/mailx/popen.c (revision 533affcbc7fc4d0c8132976ea454aaa715fe2307)
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) 1984, 1986, 1987, 1988, 1989 AT&T	*/
23 /*	  All Rights Reserved  	*/
24 
25 
26 /*
27  * University Copyright- Copyright (c) 1982, 1986, 1988
28  * The Regents of the University of California
29  * All Rights Reserved
30  *
31  * University Acknowledgment- Portions of this document are derived from
32  * software developed by the University of California, Berkeley, and its
33  * contributors.
34  */
35 
36 /*
37  * mailx -- a modified version of a University of California at Berkeley
38  *	mail program
39  *
40  * npopen() and npclose()
41  *
42  * stolen from C library, modified to use SHELL variable
43  */
44 
45 
46 #include <stdio.h>
47 #include <signal.h>
48 #include <fcntl.h>
49 
50 #define	tst(a,b) (*mode == 'r'? (b) : (a))
51 #define	RDR	0
52 #define	WTR	1
53 
54 #ifdef VMUNIX
55 #define	sigset	signal
56 #else
57 extern void (*sigset())();
58 #endif
59 #ifdef preSVr4
60 extern FILE *fdopen();
61 extern int execlp(), fork(), pipe(), close(), fcntl();
62 #ifndef sun
63 typedef int pid_t;
64 #endif
65 #else
66 # include <unistd.h>
67 # include <wait.h>
68 #endif
69 static pid_t popen_pid[20];
70 
71 FILE *
72 npopen(char *cmd, char *mode)
73 {
74 	int	p[2];
75 	register pid_t pid;
76 	register int myside, yourside;
77 	char *Shell, *value(char *);
78 
79 	if ((Shell = value("SHELL")) == NULL || *Shell=='\0')
80 #ifdef preSVr4
81 		Shell = "/bin/sh";
82 #else
83 		Shell = "/usr/bin/sh";
84 #endif
85 	if(pipe(p) < 0)
86 		return(NULL);
87 	myside = tst(p[WTR], p[RDR]);
88 	yourside = tst(p[RDR], p[WTR]);
89 	if((pid = fork()) == 0) {
90 		/* myside and yourside reverse roles in child */
91 		int	stdio;
92 
93 		stdio = tst(0, 1);
94 		(void) close(myside);
95 		(void) close(stdio);
96 		(void) fcntl(yourside, 0, stdio);
97 		(void) close(yourside);
98 		(void) execlp(Shell, Shell, "-c", cmd, (char *)0);
99 		perror(Shell);
100 		_exit(1);
101 	}
102 	if(pid == (pid_t)-1)
103 		return(NULL);
104 	popen_pid[myside] = pid;
105 	(void) close(yourside);
106 	return(fdopen(myside, mode));
107 }
108 
109 int
110 npclose(FILE *ptr)
111 {
112 	register int f;
113 	register pid_t r;
114 	int status;
115 	void (*istat)(int), (*qstat)(int);
116 
117 	f = fileno(ptr);
118 	(void) fclose(ptr);
119 	istat = sigset(SIGINT, SIG_IGN);
120 	qstat = sigset(SIGQUIT, SIG_IGN);
121 	while((r = wait(&status)) != popen_pid[f] && r != (pid_t)-1)
122 		;
123 	if(r == (pid_t)-1)
124 		status = -1;
125 	(void) sigset(SIGINT, istat);
126 	(void) sigset(SIGQUIT, qstat);
127 	return(status);
128 }
129