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 * Redistribution and use in source and binary forms are permitted 9 * provided that the above copyright notice and this paragraph are 10 * duplicated in all such forms and that any documentation, 11 * advertising materials, and other materials related to such 12 * distribution and use acknowledge that the software was developed 13 * by the University of California, Berkeley. The name of the 14 * University may not be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR 17 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED 18 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE. 19 */ 20 21 #if defined(LIBC_SCCS) && !defined(lint) 22 static char sccsid[] = "@(#)popen.c 5.12 (Berkeley) 04/06/90"; 23 #endif /* LIBC_SCCS and not lint */ 24 25 #include <sys/param.h> 26 #include <sys/signal.h> 27 #include <sys/wait.h> 28 #include <errno.h> 29 #include <stdio.h> 30 #include <unistd.h> 31 #include <paths.h> 32 33 static pid_t *pids; 34 static int fds; 35 36 FILE * 37 popen(program, type) 38 char *program, *type; 39 { 40 FILE *iop; 41 int pdes[2], pid; 42 char *malloc(); 43 44 if (*type != 'r' && *type != 'w' || type[1]) 45 return(NULL); 46 47 if (pids == NULL) { 48 if ((fds = getdtablesize()) <= 0) 49 return(NULL); 50 if ((pids = (pid_t *)malloc((u_int)(fds * sizeof(int)))) == NULL) 51 return(NULL); 52 bzero((char *)pids, fds * sizeof(pid_t)); 53 } 54 if (pipe(pdes) < 0) 55 return(NULL); 56 switch (pid = vfork()) { 57 case -1: /* error */ 58 (void)close(pdes[0]); 59 (void)close(pdes[1]); 60 return(NULL); 61 /* NOTREACHED */ 62 case 0: /* child */ 63 if (*type == 'r') { 64 if (pdes[1] != STDOUT_FILENO) { 65 (void)dup2(pdes[1], STDOUT_FILENO); 66 (void)close(pdes[1]); 67 } 68 (void)close(pdes[0]); 69 } else { 70 if (pdes[0] != STDIN_FILENO) { 71 (void)dup2(pdes[0], STDIN_FILENO); 72 (void)close(pdes[0]); 73 } 74 (void)close(pdes[1]); 75 } 76 execl(_PATH_BSHELL, "sh", "-c", program, NULL); 77 _exit(127); 78 /* NOTREACHED */ 79 } 80 /* parent; assume fdopen can't fail... */ 81 if (*type == 'r') { 82 iop = fdopen(pdes[0], type); 83 (void)close(pdes[1]); 84 } else { 85 iop = fdopen(pdes[1], type); 86 (void)close(pdes[0]); 87 } 88 pids[fileno(iop)] = pid; 89 return(iop); 90 } 91 92 pclose(iop) 93 FILE *iop; 94 { 95 extern int errno; 96 register int fdes; 97 int omask; 98 union wait pstat; 99 pid_t pid, waitpid(); 100 101 /* 102 * pclose returns -1 if stream is not associated with a 103 * `popened' command, if already `pclosed', or waitpid 104 * returns an error. 105 */ 106 if (pids == NULL || pids[fdes = fileno(iop)] == 0) 107 return(-1); 108 (void)fclose(iop); 109 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP)); 110 do { 111 pid = waitpid(pids[fdes], &pstat, 0); 112 } while (pid == -1 && errno == EINTR); 113 (void)sigsetmask(omask); 114 pids[fdes] = 0; 115 return(pid == -1 ? -1 : pstat.w_status); 116 } 117