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 * static char sccsid[] = "@(#)popen.c 5.7 (Berkeley) 9/1/88"; 21 */ 22 23 #ifndef lint 24 static char sccsid[] = "@(#)popen.c 5.1 (Berkeley) 09/22/88"; 25 #endif /* not lint */ 26 27 #include <sys/param.h> 28 #include <sys/signal.h> 29 #include <sys/wait.h> 30 #include <stdio.h> 31 32 static uid_t *pids; 33 static int fds; 34 35 FILE * 36 popen(program, type) 37 char *program, *type; 38 { 39 FILE *iop; 40 int pdes[2], pid; 41 char *malloc(); 42 43 if (*type != 'r' && *type != 'w' || type[1]) 44 return(NULL); 45 46 if (!pids) { 47 if ((fds = getdtablesize()) <= 0) 48 return(NULL); 49 if (!(pids = 50 (uid_t *)malloc((u_int)(fds * sizeof(uid_t))))) 51 return(NULL); 52 bzero(pids, fds * sizeof(uid_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] != 1) { 65 dup2(pdes[1], 1); 66 (void)close(pdes[1]); 67 } 68 (void)close(pdes[0]); 69 } else { 70 if (pdes[0] != 0) { 71 dup2(pdes[0], 0); 72 (void)close(pdes[0]); 73 } 74 (void)close(pdes[1]); 75 } 76 execl("/bin/sh", "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 register int fdes; 96 long omask; 97 int stat_loc; 98 pid_t waitpid(); 99 100 /* 101 * pclose returns -1 if stream is not associated with a 102 * `popened' command, or, if already `pclosed'. 103 */ 104 if (pids[fdes = fileno(iop)] == 0) 105 return(-1); 106 (void)fclose(iop); 107 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP)); 108 stat_loc = waitpid(pids[fdes], &stat_loc, 0) == -1 ? 109 -1 : WEXITSTATUS(stat_loc); 110 (void)sigsetmask(omask); 111 pids[fdes] = 0; 112 return(stat_loc); 113 } 114