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 5.10 (Berkeley) 10/09/89"; 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 <stdio.h> 29 #include <paths.h> 30 31 static pid_t *pids; 32 static int fds; 33 34 FILE * 35 popen(program, type) 36 char *program, *type; 37 { 38 FILE *iop; 39 int pdes[2], pid; 40 char *malloc(); 41 42 if (*type != 'r' && *type != 'w' || type[1]) 43 return(NULL); 44 45 if (pids == NULL) { 46 if ((fds = getdtablesize()) <= 0) 47 return(NULL); 48 if ((pids = (pid_t *)malloc((u_int)(fds * sizeof(int)))) == NULL) 49 return(NULL); 50 bzero((char *)pids, fds * sizeof(pid_t)); 51 } 52 if (pipe(pdes) < 0) 53 return(NULL); 54 switch (pid = vfork()) { 55 case -1: /* error */ 56 (void)close(pdes[0]); 57 (void)close(pdes[1]); 58 return(NULL); 59 /* NOTREACHED */ 60 case 0: /* child */ 61 if (*type == 'r') { 62 if (pdes[1] != 1) { 63 dup2(pdes[1], 1); 64 (void)close(pdes[1]); 65 } 66 (void)close(pdes[0]); 67 } else { 68 if (pdes[0] != 0) { 69 dup2(pdes[0], 0); 70 (void)close(pdes[0]); 71 } 72 (void)close(pdes[1]); 73 } 74 execl(_PATH_BSHELL, "sh", "-c", program, NULL); 75 _exit(127); 76 /* NOTREACHED */ 77 } 78 /* parent; assume fdopen can't fail... */ 79 if (*type == 'r') { 80 iop = fdopen(pdes[0], type); 81 (void)close(pdes[1]); 82 } else { 83 iop = fdopen(pdes[1], type); 84 (void)close(pdes[0]); 85 } 86 pids[fileno(iop)] = pid; 87 return(iop); 88 } 89 90 pclose(iop) 91 FILE *iop; 92 { 93 register int fdes; 94 int omask; 95 union wait pstat; 96 pid_t pid, waitpid(); 97 98 /* 99 * pclose returns -1 if stream is not associated with a 100 * `popened' command, if already `pclosed', or waitpid 101 * returns an error. 102 */ 103 if (pids == NULL || pids[fdes = fileno(iop)] == 0) 104 return(-1); 105 (void)fclose(iop); 106 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP)); 107 pid = waitpid(pids[fdes], &pstat, 0); 108 (void)sigsetmask(omask); 109 pids[fdes] = 0; 110 return(pid == -1 ? -1 : pstat.w_status); 111 } 112