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 5.2 (Berkeley) 09/22/88"; 25 #endif /* not lint */ 26 27 #include <sys/types.h> 28 #include <sys/signal.h> 29 #include <stdio.h> 30 31 /* 32 * Special version of popen which avoids call to shell. This insures noone 33 * may create a pipe to a hidden program as a side effect of a list or dir 34 * command. 35 */ 36 static uid_t *pids; 37 static int fds; 38 39 FILE * 40 popen(program, type) 41 char *program, *type; 42 { 43 register char *cp; 44 FILE *iop; 45 int argc, gargc, pdes[2], pid; 46 char **pop, *argv[100], *gargv[1000], *vv[2]; 47 extern char **glob(), **copyblk(), *strtok(); 48 49 if (*type != 'r' && *type != 'w' || type[1]) 50 return(NULL); 51 52 if (!pids) { 53 if ((fds = getdtablesize()) <= 0) 54 return(NULL); 55 if (!(pids = 56 (uid_t *)malloc((u_int)(fds * sizeof(uid_t))))) 57 return(NULL); 58 bzero(pids, fds * sizeof(uid_t)); 59 } 60 if (pipe(pdes) < 0) 61 return(NULL); 62 63 /* break up string into pieces */ 64 for (argc = 0, cp = program;; cp = NULL) 65 if (!(argv[argc++] = strtok(cp, " \t\n"))) 66 break; 67 68 /* glob each piece */ 69 gargv[0] = argv[0]; 70 for (gargc = argc = 1; argv[argc]; argc++) { 71 if (!(pop = glob(argv[argc]))) { /* globbing failed */ 72 vv[0] = argv[argc]; 73 vv[1] = NULL; 74 pop = copyblk(vv); 75 } 76 argv[argc] = (char *)pop; /* save to free later */ 77 while (*pop && gargc < 1000) 78 gargv[gargc++] = *pop++; 79 } 80 gargv[gargc] = NULL; 81 82 iop = NULL; 83 switch(pid = vfork()) { 84 case -1: /* error */ 85 (void)close(pdes[0]); 86 (void)close(pdes[1]); 87 goto free; 88 /* NOTREACHED */ 89 case 0: /* child */ 90 if (*type == 'r') { 91 if (pdes[1] != 1) { 92 dup2(pdes[1], 1); 93 (void)close(pdes[1]); 94 } 95 (void)close(pdes[0]); 96 } else { 97 if (pdes[0] != 0) { 98 dup2(pdes[0], 0); 99 (void)close(pdes[0]); 100 } 101 (void)close(pdes[1]); 102 } 103 execv(gargv[0], gargv); 104 _exit(1); 105 } 106 /* parent; assume fdopen can't fail... */ 107 if (*type == 'r') { 108 iop = fdopen(pdes[0], type); 109 (void)close(pdes[1]); 110 } else { 111 iop = fdopen(pdes[1], type); 112 (void)close(pdes[0]); 113 } 114 pids[fileno(iop)] = pid; 115 116 free: for (argc = 1; argv[argc] != NULL; argc++) 117 blkfree((char **)argv[argc]); 118 return(iop); 119 } 120 121 pclose(iop) 122 FILE *iop; 123 { 124 register int fdes; 125 long omask; 126 int pid, stat_loc; 127 u_int waitpid(); 128 129 /* 130 * pclose returns -1 if stream is not associated with a 131 * `popened' command, or, if already `pclosed'. 132 */ 133 if (pids[fdes = fileno(iop)] == 0) 134 return(-1); 135 (void)fclose(iop); 136 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP)); 137 while ((pid = wait(&stat_loc)) != pids[fdes] && pid != -1); 138 (void)sigsetmask(omask); 139 pids[fdes] = 0; 140 return(stat_loc); 141 } 142