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 * %sccs.include.redist.c% 9 */ 10 11 #if defined(LIBC_SCCS) && !defined(lint) 12 static char sccsid[] = "@(#)popen.c 5.15 (Berkeley) 02/23/91"; 13 #endif /* LIBC_SCCS and not lint */ 14 15 #include <sys/param.h> 16 #include <sys/signal.h> 17 #include <sys/wait.h> 18 #include <errno.h> 19 #include <stdio.h> 20 #include <stdlib.h> 21 #include <string.h> 22 #include <unistd.h> 23 #include <paths.h> 24 25 static pid_t *pids; 26 27 FILE * 28 popen(program, type) 29 const char *program; 30 const char *type; 31 { 32 FILE *iop; 33 int pdes[2], fds, pid; 34 35 if (*type != 'r' && *type != 'w' || type[1]) 36 return (NULL); 37 38 if (pids == NULL) { 39 if ((fds = getdtablesize()) <= 0) 40 return (NULL); 41 if ((pids = (pid_t *)malloc((u_int)(fds * sizeof(int)))) == NULL) 42 return (NULL); 43 bzero((char *)pids, fds * sizeof(pid_t)); 44 } 45 if (pipe(pdes) < 0) 46 return (NULL); 47 switch (pid = vfork()) { 48 case -1: /* error */ 49 (void) close(pdes[0]); 50 (void) close(pdes[1]); 51 return (NULL); 52 /* NOTREACHED */ 53 case 0: /* child */ 54 if (*type == 'r') { 55 if (pdes[1] != STDOUT_FILENO) { 56 (void) dup2(pdes[1], STDOUT_FILENO); 57 (void) close(pdes[1]); 58 } 59 (void) close(pdes[0]); 60 } else { 61 if (pdes[0] != STDIN_FILENO) { 62 (void) dup2(pdes[0], STDIN_FILENO); 63 (void) close(pdes[0]); 64 } 65 (void) close(pdes[1]); 66 } 67 execl(_PATH_BSHELL, "sh", "-c", program, NULL); 68 _exit(127); 69 /* NOTREACHED */ 70 } 71 /* parent; assume fdopen can't fail... */ 72 if (*type == 'r') { 73 iop = fdopen(pdes[0], type); 74 (void) close(pdes[1]); 75 } else { 76 iop = fdopen(pdes[1], type); 77 (void) close(pdes[0]); 78 } 79 pids[fileno(iop)] = pid; 80 return (iop); 81 } 82 83 int 84 pclose(iop) 85 FILE *iop; 86 { 87 register int fdes; 88 int omask; 89 union wait pstat; 90 pid_t pid; 91 92 /* 93 * pclose returns -1 if stream is not associated with a 94 * `popened' command, if already `pclosed', or waitpid 95 * returns an error. 96 */ 97 if (pids == NULL || pids[fdes = fileno(iop)] == 0) 98 return (-1); 99 (void) fclose(iop); 100 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP)); 101 do { 102 pid = waitpid(pids[fdes], (int *) &pstat, 0); 103 } while (pid == -1 && errno == EINTR); 104 (void) sigsetmask(omask); 105 pids[fdes] = 0; 106 return (pid == -1 ? -1 : pstat.w_status); 107 } 108