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 * 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 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