| 1 | /*
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| 2 | * popen - open a pipe
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| 3 | */
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| 4 | /* $Header: /cvsup/minix/src/lib/other/popen.c,v 1.1.1.1 2005/04/21 14:56:27 beng Exp $ */
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| 5 |
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| 6 | #include <sys/types.h>
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| 7 | #include <limits.h>
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| 8 | #include <errno.h>
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| 9 | #include <signal.h>
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| 10 | #include <stdio.h>
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| 11 |
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| 12 | #if defined(__BSD4_2)
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| 13 | union wait {
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| 14 | int w_status;
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| 15 | };
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| 16 | typedef union wait wait_arg;
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| 17 | #else
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| 18 | typedef int wait_arg;
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| 19 | #endif /* __BSD4_2 */
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| 20 |
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| 21 | #include "../stdio/loc_incl.h"
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| 22 |
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| 23 | #ifdef _ANSI
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| 24 | int _close(int d);
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| 25 | int _dup2(int oldd, int newd); /* not present in System 5 */
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| 26 | int _execl(const char *name, const char *_arg, ... );
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| 27 | pid_t _fork(void);
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| 28 | int _pipe(int fildes[2]);
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| 29 | pid_t _wait(wait_arg *status);
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| 30 | void _exit(int status);
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| 31 | #endif
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| 32 |
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| 33 | static int pids[OPEN_MAX];
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| 34 |
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| 35 | FILE *
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| 36 | popen(command, type)
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| 37 | _CONST char *command;
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| 38 | _CONST char *type;
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| 39 | {
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| 40 | int piped[2];
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| 41 | int Xtype = *type == 'r' ? 0 : *type == 'w' ? 1 : 2;
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| 42 | int pid;
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| 43 |
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| 44 | if (Xtype == 2 ||
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| 45 | _pipe(piped) < 0 ||
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| 46 | (pid = _fork()) < 0) return 0;
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| 47 |
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| 48 | if (pid == 0) {
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| 49 | /* child */
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| 50 | register int *p;
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| 51 |
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| 52 | for (p = pids; p < &pids[OPEN_MAX]; p++) {
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| 53 | if (*p) _close((int)(p - pids));
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| 54 | }
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| 55 | _close(piped[Xtype]);
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| 56 | _dup2(piped[!Xtype], !Xtype);
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| 57 | _close(piped[!Xtype]);
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| 58 | _execl("/bin/sh", "sh", "-c", command, (char *) 0);
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| 59 | _exit(127); /* like system() ??? */
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| 60 | }
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| 61 |
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| 62 | pids[piped[Xtype]] = pid;
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| 63 | _close(piped[!Xtype]);
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| 64 | return fdopen(piped[Xtype], type);
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| 65 | }
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| 66 |
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| 67 | #if defined(__BSD4_2)
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| 68 | #define ret_val status.w_status
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| 69 | #else
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| 70 | #define ret_val status
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| 71 | #endif
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| 72 |
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| 73 | int
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| 74 | pclose(stream)
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| 75 | FILE *stream;
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| 76 | {
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| 77 | int fd = fileno(stream);
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| 78 | wait_arg status;
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| 79 | int wret;
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| 80 |
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| 81 | #ifdef _ANSI
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| 82 | void (*intsave)(int) = signal(SIGINT, SIG_IGN);
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| 83 | void (*quitsave)(int) = signal(SIGQUIT, SIG_IGN);
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| 84 | #else
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| 85 | void (*intsave)() = signal(SIGINT, SIG_IGN);
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| 86 | void (*quitsave)() = signal(SIGQUIT, SIG_IGN);
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| 87 | #endif
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| 88 | fclose(stream);
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| 89 | while ((wret = _wait(&status)) != -1) {
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| 90 | if (wret == pids[fd]) break;
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| 91 | }
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| 92 | if (wret == -1) ret_val = -1;
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| 93 | signal(SIGINT, intsave);
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| 94 | signal(SIGQUIT, quitsave);
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| 95 | pids[fd] = 0;
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| 96 | return ret_val;
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| 97 | }
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| 98 |
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| 99 | #if defined(__USG)
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| 100 | int _dup(int fildes);
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| 101 |
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| 102 | static int
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| 103 | _dup2(oldd, newd)
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| 104 | int oldd, newd;
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| 105 | {
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| 106 | int i = 0, fd, tmp;
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| 107 | int fdbuf[_NFILES];
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| 108 |
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| 109 | /* ignore the error on the close() */
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| 110 | tmp = errno; (void) _close(newd); errno = tmp;
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| 111 | while ((fd = _dup(oldd)) != newd) {
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| 112 | if (fd == -1) break;
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| 113 | fdbuf[i++] = fd;
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| 114 | }
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| 115 | tmp = errno;
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| 116 | while (--i >= 0) {
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| 117 | _close(fdbuf[i]);
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| 118 | }
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| 119 | errno = tmp;
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| 120 | return -(fd == -1);
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| 121 | }
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| 122 | #endif /* __USG */
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