popen.c revision 2311
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 MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 19 * 20 */ 21 22/* this came out of the ftpd sources; it's been modified to avoid the 23 * globbing stuff since we don't need it. also execvp instead of execv. 24 */ 25 26#ifndef lint 27static char rcsid[] = "$Id: popen.c,v 1.5 1994/01/15 20:43:43 vixie Exp $"; 28static char sccsid[] = "@(#)popen.c 5.7 (Berkeley) 2/14/89"; 29#endif /* not lint */ 30 31#include "cron.h" 32#include <sys/signal.h> 33 34 35#define WANT_GLOBBING 0 36 37/* 38 * Special version of popen which avoids call to shell. This insures noone 39 * may create a pipe to a hidden program as a side effect of a list or dir 40 * command. 41 */ 42static PID_T *pids; 43static int fds; 44 45FILE * 46cron_popen(program, type) 47 char *program, *type; 48{ 49 register char *cp; 50 FILE *iop; 51 int argc, pdes[2]; 52 PID_T pid; 53 char *argv[100]; 54#if WANT_GLOBBING 55 char **pop, *vv[2]; 56 int gargc; 57 char *gargv[1000]; 58 extern char **glob(), **copyblk(); 59#endif 60 61 if (*type != 'r' && *type != 'w' || type[1]) 62 return(NULL); 63 64 if (!pids) { 65 if ((fds = getdtablesize()) <= 0) 66 return(NULL); 67 if (!(pids = (PID_T *)malloc((u_int)(fds * sizeof(PID_T))))) 68 return(NULL); 69 bzero((char *)pids, fds * sizeof(PID_T)); 70 } 71 if (pipe(pdes) < 0) 72 return(NULL); 73 74 /* break up string into pieces */ 75 for (argc = 0, cp = program;; cp = NULL) 76 if (!(argv[argc++] = strtok(cp, " \t\n"))) 77 break; 78 79#if WANT_GLOBBING 80 /* glob each piece */ 81 gargv[0] = argv[0]; 82 for (gargc = argc = 1; argv[argc]; argc++) { 83 if (!(pop = glob(argv[argc]))) { /* globbing failed */ 84 vv[0] = argv[argc]; 85 vv[1] = NULL; 86 pop = copyblk(vv); 87 } 88 argv[argc] = (char *)pop; /* save to free later */ 89 while (*pop && gargc < 1000) 90 gargv[gargc++] = *pop++; 91 } 92 gargv[gargc] = NULL; 93#endif 94 95 iop = NULL; 96 switch(pid = vfork()) { 97 case -1: /* error */ 98 (void)close(pdes[0]); 99 (void)close(pdes[1]); 100 goto pfree; 101 /* NOTREACHED */ 102 case 0: /* child */ 103 if (*type == 'r') { 104 if (pdes[1] != 1) { 105 dup2(pdes[1], 1); 106 dup2(pdes[1], 2); /* stderr, too! */ 107 (void)close(pdes[1]); 108 } 109 (void)close(pdes[0]); 110 } else { 111 if (pdes[0] != 0) { 112 dup2(pdes[0], 0); 113 (void)close(pdes[0]); 114 } 115 (void)close(pdes[1]); 116 } 117#if WANT_GLOBBING 118 execvp(gargv[0], gargv); 119#else 120 execvp(argv[0], argv); 121#endif 122 _exit(1); 123 } 124 /* parent; assume fdopen can't fail... */ 125 if (*type == 'r') { 126 iop = fdopen(pdes[0], type); 127 (void)close(pdes[1]); 128 } else { 129 iop = fdopen(pdes[1], type); 130 (void)close(pdes[0]); 131 } 132 pids[fileno(iop)] = pid; 133 134pfree: 135#if WANT_GLOBBING 136 for (argc = 1; argv[argc] != NULL; argc++) { 137/* blkfree((char **)argv[argc]); */ 138 free((char *)argv[argc]); 139 } 140#endif 141 return(iop); 142} 143 144int 145cron_pclose(iop) 146 FILE *iop; 147{ 148 register int fdes; 149 int omask; 150 WAIT_T stat_loc; 151 PID_T pid; 152 153 /* 154 * pclose returns -1 if stream is not associated with a 155 * `popened' command, or, if already `pclosed'. 156 */ 157 if (pids == 0 || pids[fdes = fileno(iop)] == 0) 158 return(-1); 159 (void)fclose(iop); 160 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP)); 161 while ((pid = wait(&stat_loc)) != pids[fdes] && pid != -1) 162 ; 163 (void)sigsetmask(omask); 164 pids[fdes] = 0; 165 return (pid == -1 ? -1 : WEXITSTATUS(stat_loc)); 166} 167