Commit | Line | Data |
---|---|---|
01a56307 BJ |
1 | /* @(#)popen.c 4.1 (Berkeley) %G% */ |
2 | #include <stdio.h> | |
3 | #include <signal.h> | |
4 | #define tst(a,b) (*mode == 'r'? (b) : (a)) | |
5 | #define RDR 0 | |
6 | #define WTR 1 | |
7 | static int popen_pid[20]; | |
8 | ||
9 | FILE * | |
10 | popen(cmd,mode) | |
11 | char *cmd; | |
12 | char *mode; | |
13 | { | |
14 | int p[2]; | |
15 | register myside, hisside, pid; | |
16 | ||
17 | if(pipe(p) < 0) | |
18 | return NULL; | |
19 | myside = tst(p[WTR], p[RDR]); | |
20 | hisside = tst(p[RDR], p[WTR]); | |
21 | if((pid = vfork()) == 0) { | |
22 | /* myside and hisside reverse roles in child */ | |
23 | close(myside); | |
24 | dup2(hisside, tst(0, 1)); | |
25 | close(hisside); | |
26 | execl("/bin/sh", "sh", "-c", cmd, 0); | |
27 | _exit(1); | |
28 | } | |
29 | if(pid == -1) | |
30 | return NULL; | |
31 | popen_pid[myside] = pid; | |
32 | close(hisside); | |
33 | return(fdopen(myside, mode)); | |
34 | } | |
35 | ||
36 | pclose(ptr) | |
37 | FILE *ptr; | |
38 | { | |
39 | register f, r, (*hstat)(), (*istat)(), (*qstat)(); | |
40 | int status; | |
41 | ||
42 | f = fileno(ptr); | |
43 | fclose(ptr); | |
44 | istat = signal(SIGINT, SIG_IGN); | |
45 | qstat = signal(SIGQUIT, SIG_IGN); | |
46 | hstat = signal(SIGHUP, SIG_IGN); | |
47 | while((r = wait(&status)) != popen_pid[f] && r != -1) | |
48 | ; | |
49 | if(r == -1) | |
50 | status = -1; | |
51 | signal(SIGINT, istat); | |
52 | signal(SIGQUIT, qstat); | |
53 | signal(SIGHUP, hstat); | |
54 | return(status); | |
55 | } |