popen.c revision 20573
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 1.1.1.1 1995/10/18 08:47:31 deraadt 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 MAX_ARGS 100 36#define WANT_GLOBBING 0 37 38/* 39 * Special version of popen which avoids call to shell. This insures noone 40 * may create a pipe to a hidden program as a side effect of a list or dir 41 * command. 42 */ 43static PID_T *pids; 44static int fds; 45 46FILE * 47cron_popen(program, type) 48 char *program, *type; 49{ 50 register char *cp; 51 FILE *iop; 52 int argc, pdes[2]; 53 PID_T pid; 54 char *argv[MAX_ARGS + 1]; 55#if WANT_GLOBBING 56 char **pop, *vv[2]; 57 int gargc; 58 char *gargv[1000]; 59 extern char **glob(), **copyblk(); 60#endif 61 62 if (*type != 'r' && *type != 'w' || type[1]) 63 return(NULL); 64 65 if (!pids) { 66 if ((fds = getdtablesize()) <= 0) 67 return(NULL); 68 if (!(pids = (PID_T *)malloc((u_int)(fds * sizeof(PID_T))))) 69 return(NULL); 70 bzero((char *)pids, fds * sizeof(PID_T)); 71 } 72 if (pipe(pdes) < 0) 73 return(NULL); 74 75 /* break up string into pieces */ 76 for (argc = 0, cp = program; argc < MAX_ARGS; cp = NULL) 77 if (!(argv[argc++] = strtok(cp, " \t\n"))) 78 break; 79 80#if WANT_GLOBBING 81 /* glob each piece */ 82 gargv[0] = argv[0]; 83 for (gargc = argc = 1; argv[argc]; argc++) { 84 if (!(pop = glob(argv[argc]))) { /* globbing failed */ 85 vv[0] = argv[argc]; 86 vv[1] = NULL; 87 pop = copyblk(vv); 88 } 89 argv[argc] = (char *)pop; /* save to free later */ 90 while (*pop && gargc < 1000) 91 gargv[gargc++] = *pop++; 92 } 93 gargv[gargc] = NULL; 94#endif 95 96 iop = NULL; 97 switch(pid = vfork()) { 98 case -1: /* error */ 99 (void)close(pdes[0]); 100 (void)close(pdes[1]); 101 goto pfree; 102 /* NOTREACHED */ 103 case 0: /* child */ 104 if (*type == 'r') { 105 if (pdes[1] != 1) { 106 dup2(pdes[1], 1); 107 dup2(pdes[1], 2); /* stderr, too! */ 108 (void)close(pdes[1]); 109 } 110 (void)close(pdes[0]); 111 } else { 112 if (pdes[0] != 0) { 113 dup2(pdes[0], 0); 114 (void)close(pdes[0]); 115 } 116 (void)close(pdes[1]); 117 } 118#if WANT_GLOBBING 119 execvp(gargv[0], gargv); 120#else 121 execvp(argv[0], argv); 122#endif 123 _exit(1); 124 } 125 /* parent; assume fdopen can't fail... */ 126 if (*type == 'r') { 127 iop = fdopen(pdes[0], type); 128 (void)close(pdes[1]); 129 } else { 130 iop = fdopen(pdes[1], type); 131 (void)close(pdes[0]); 132 } 133 pids[fileno(iop)] = pid; 134 135pfree: 136#if WANT_GLOBBING 137 for (argc = 1; argv[argc] != NULL; argc++) { 138/* blkfree((char **)argv[argc]); */ 139 free((char *)argv[argc]); 140 } 141#endif 142 return(iop); 143} 144 145int 146cron_pclose(iop) 147 FILE *iop; 148{ 149 register int fdes; 150 int omask; 151 WAIT_T stat_loc; 152 PID_T pid; 153 154 /* 155 * pclose returns -1 if stream is not associated with a 156 * `popened' command, or, if already `pclosed'. 157 */ 158 if (pids == 0 || pids[fdes = fileno(iop)] == 0) 159 return(-1); 160 (void)fclose(iop); 161 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP)); 162 while ((pid = wait(&stat_loc)) != pids[fdes] && pid != -1) 163 ; 164 (void)sigsetmask(omask); 165 pids[fdes] = 0; 166 return (pid == -1 ? -1 : WEXITSTATUS(stat_loc)); 167} 168