Annotation of src/lib/libc/gen/popen.c, Revision 1.1.1.1
1.1 cgd 1: /*
2: * Copyright (c) 1988 The Regents of the University of California.
3: * All rights reserved.
4: *
5: * This code is derived from software written by Ken Arnold and
6: * published in UNIX Review, Vol. 6, No. 8.
7: *
8: * Redistribution and use in source and binary forms, with or without
9: * modification, are permitted provided that the following conditions
10: * are met:
11: * 1. Redistributions of source code must retain the above copyright
12: * notice, this list of conditions and the following disclaimer.
13: * 2. Redistributions in binary form must reproduce the above copyright
14: * notice, this list of conditions and the following disclaimer in the
15: * documentation and/or other materials provided with the distribution.
16: * 3. All advertising materials mentioning features or use of this software
17: * must display the following acknowledgement:
18: * This product includes software developed by the University of
19: * California, Berkeley and its contributors.
20: * 4. Neither the name of the University nor the names of its contributors
21: * may be used to endorse or promote products derived from this software
22: * without specific prior written permission.
23: *
24: * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
25: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
26: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
27: * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
28: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
29: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
30: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
31: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
33: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
34: * SUCH DAMAGE.
35: */
36:
37: #if defined(LIBC_SCCS) && !defined(lint)
38: static char sccsid[] = "@(#)popen.c 5.15 (Berkeley) 2/23/91";
39: #endif /* LIBC_SCCS and not lint */
40:
41: #include <sys/param.h>
42: #include <sys/signal.h>
43: #include <sys/wait.h>
44: #include <errno.h>
45: #include <stdio.h>
46: #include <stdlib.h>
47: #include <string.h>
48: #include <unistd.h>
49: #include <paths.h>
50:
51: static pid_t *pids;
52:
53: FILE *
54: popen(program, type)
55: const char *program;
56: const char *type;
57: {
58: FILE *iop;
59: int pdes[2], fds, pid;
60:
61: if (*type != 'r' && *type != 'w' || type[1])
62: return (NULL);
63:
64: if (pids == NULL) {
65: if ((fds = getdtablesize()) <= 0)
66: return (NULL);
67: if ((pids = (pid_t *)malloc((u_int)(fds * sizeof(int)))) == NULL)
68: return (NULL);
69: bzero((char *)pids, fds * sizeof(pid_t));
70: }
71: if (pipe(pdes) < 0)
72: return (NULL);
73: switch (pid = vfork()) {
74: case -1: /* error */
75: (void) close(pdes[0]);
76: (void) close(pdes[1]);
77: return (NULL);
78: /* NOTREACHED */
79: case 0: /* child */
80: if (*type == 'r') {
81: if (pdes[1] != STDOUT_FILENO) {
82: (void) dup2(pdes[1], STDOUT_FILENO);
83: (void) close(pdes[1]);
84: }
85: (void) close(pdes[0]);
86: } else {
87: if (pdes[0] != STDIN_FILENO) {
88: (void) dup2(pdes[0], STDIN_FILENO);
89: (void) close(pdes[0]);
90: }
91: (void) close(pdes[1]);
92: }
93: execl(_PATH_BSHELL, "sh", "-c", program, NULL);
94: _exit(127);
95: /* NOTREACHED */
96: }
97: /* parent; assume fdopen can't fail... */
98: if (*type == 'r') {
99: iop = fdopen(pdes[0], type);
100: (void) close(pdes[1]);
101: } else {
102: iop = fdopen(pdes[1], type);
103: (void) close(pdes[0]);
104: }
105: pids[fileno(iop)] = pid;
106: return (iop);
107: }
108:
109: int
110: pclose(iop)
111: FILE *iop;
112: {
113: register int fdes;
114: int omask;
115: union wait pstat;
116: pid_t pid;
117:
118: /*
119: * pclose returns -1 if stream is not associated with a
120: * `popened' command, if already `pclosed', or waitpid
121: * returns an error.
122: */
123: if (pids == NULL || pids[fdes = fileno(iop)] == 0)
124: return (-1);
125: (void) fclose(iop);
126: omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP));
127: do {
128: pid = waitpid(pids[fdes], (int *) &pstat, 0);
129: } while (pid == -1 && errno == EINTR);
130: (void) sigsetmask(omask);
131: pids[fdes] = 0;
132: return (pid == -1 ? -1 : pstat.w_status);
133: }
CVSweb <webmaster@jp.NetBSD.org>