1 /*
2 * Copyright (c) 1988, 1993
3 * The Regents of the University of California. 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 * %sccs.include.redist.c%
9 */
10
11 #if defined(LIBC_SCCS) && !defined(lint)
12 static char sccsid[] = "@(#)popen.c 8.3 (Berkeley) 05/03/95";
13 #endif /* LIBC_SCCS and not lint */
14
15 #include <sys/param.h>
16 #include <sys/wait.h>
17 #include <sys/socket.h>
18
19 #include <signal.h>
20 #include <errno.h>
21 #include <unistd.h>
22 #include <stdio.h>
23 #include <stdlib.h>
24 #include <string.h>
25 #include <paths.h>
26
27 static struct pid {
28 struct pid *next;
29 FILE *fp;
30 pid_t pid;
31 } *pidlist;
32
33 FILE *
popen(command,type)34 popen(command, type)
35 const char *command, *type;
36 {
37 struct pid *cur;
38 FILE *iop;
39 int pdes[2], pid, twoway;
40
41 if (strchr(type, '+')) {
42 twoway = 1;
43 type = "r+";
44 if (socketpair(AF_UNIX, SOCK_STREAM, 0, pdes) < 0)
45 return (NULL);
46 } else {
47 twoway = 0;
48 if (*type != 'r' && *type != 'w' || type[1] ||
49 (pipe(pdes) < 0))
50 return (NULL);
51 }
52
53 if ((cur = malloc(sizeof(struct pid))) == NULL)
54 return (NULL);
55
56 switch (pid = vfork()) {
57 case -1: /* Error. */
58 (void)close(pdes[0]);
59 (void)close(pdes[1]);
60 (void)free(cur);
61 return (NULL);
62 /* NOTREACHED */
63 case 0: /* Child. */
64 if (*type == 'r') {
65 if (pdes[1] != STDOUT_FILENO) {
66 (void)dup2(pdes[1], STDOUT_FILENO);
67 (void)close(pdes[1]);
68 pdes[1] = STDOUT_FILENO;
69 }
70 (void) close(pdes[0]);
71 if (twoway && (pdes[1] != STDIN_FILENO))
72 (void)dup2(pdes[1], STDIN_FILENO);
73 } else {
74 if (pdes[0] != STDIN_FILENO) {
75 (void)dup2(pdes[0], STDIN_FILENO);
76 (void)close(pdes[0]);
77 }
78 (void)close(pdes[1]);
79 }
80 execl(_PATH_BSHELL, "sh", "-c", command, NULL);
81 _exit(127);
82 /* NOTREACHED */
83 }
84
85 /* Parent; assume fdopen can't fail. */
86 if (*type == 'r') {
87 iop = fdopen(pdes[0], type);
88 (void)close(pdes[1]);
89 } else {
90 iop = fdopen(pdes[1], type);
91 (void)close(pdes[0]);
92 }
93
94 /* Link into list of file descriptors. */
95 cur->fp = iop;
96 cur->pid = pid;
97 cur->next = pidlist;
98 pidlist = cur;
99
100 return (iop);
101 }
102
103 /*
104 * pclose --
105 * Pclose returns -1 if stream is not associated with a `popened' command,
106 * if already `pclosed', or waitpid returns an error.
107 */
108 int
pclose(iop)109 pclose(iop)
110 FILE *iop;
111 {
112 register struct pid *cur, *last;
113 int omask;
114 int pstat;
115 pid_t pid;
116
117 /* Find the appropriate file pointer. */
118 for (last = NULL, cur = pidlist; cur; last = cur, cur = cur->next)
119 if (cur->fp == iop)
120 break;
121 if (cur == NULL)
122 return (-1);
123
124 (void)fclose(iop);
125
126 do {
127 pid = waitpid(cur->pid, &pstat, 0);
128 } while (pid == -1 && errno == EINTR);
129
130 /* Remove the entry from the linked list. */
131 if (last == NULL)
132 pidlist = cur->next;
133 else
134 last->next = cur->next;
135 free(cur);
136
137 return (pid == -1 ? -1 : pstat);
138 }
139