1 /* $OpenBSD: popen.c,v 1.19 2003/06/02 04:39:45 millert Exp $ */ 2 3 /* 4 * Copyright (c) 1988, 1993, 1994 5 * The Regents of the University of California. All rights reserved. 6 * 7 * This code is derived from software written by Ken Arnold and 8 * published in UNIX Review, Vol. 6, No. 8. 9 * 10 * Redistribution and use in source and binary forms, with or without 11 * modification, are permitted provided that the following conditions 12 * are met: 13 * 1. Redistributions of source code must retain the above copyright 14 * notice, this list of conditions and the following disclaimer. 15 * 2. Redistributions in binary form must reproduce the above copyright 16 * notice, this list of conditions and the following disclaimer in the 17 * documentation and/or other materials provided with the distribution. 18 * 3. Neither the name of the University nor the names of its contributors 19 * may be used to endorse or promote products derived from this software 20 * without specific prior written permission. 21 * 22 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 * 34 */ 35 36 /* this came out of the ftpd sources; it's been modified to avoid the 37 * globbing stuff since we don't need it. also execvp instead of execv. 38 */ 39 40 #ifndef lint 41 #if 0 42 static const sccsid[] = "@(#)popen.c 8.3 (Berkeley) 4/6/94"; 43 #else 44 static const char rcsid[] = "$OpenBSD: popen.c,v 1.19 2003/06/02 04:39:45 millert Exp $"; 45 #endif 46 #endif /* not lint */ 47 48 #include "cron.h" 49 50 #define MAX_ARGV 100 51 #define MAX_GARGV 1000 52 53 /* 54 * Special version of popen which avoids call to shell. This ensures noone 55 * may create a pipe to a hidden program as a side effect of a list or dir 56 * command. 57 */ 58 static PID_T *pids; 59 static int fds; 60 61 FILE * 62 cron_popen(char *program, char *type, struct passwd *pw) { 63 char *cp; 64 FILE *iop; 65 int argc, pdes[2]; 66 PID_T pid; 67 char *argv[MAX_ARGV]; 68 69 if ((*type != 'r' && *type != 'w') || type[1] != '\0') 70 return (NULL); 71 72 if (!pids) { 73 if ((fds = sysconf(_SC_OPEN_MAX)) <= 0) 74 return (NULL); 75 if (!(pids = (PID_T *)malloc((size_t)(fds * sizeof(PID_T))))) 76 return (NULL); 77 bzero(pids, fds * sizeof(PID_T)); 78 } 79 if (pipe(pdes) < 0) 80 return (NULL); 81 82 /* break up string into pieces */ 83 for (argc = 0, cp = program; argc < MAX_ARGV - 1; cp = NULL) 84 if (!(argv[argc++] = strtok(cp, " \t\n"))) 85 break; 86 argv[MAX_ARGV-1] = NULL; 87 88 switch (pid = fork()) { 89 case -1: /* error */ 90 (void)close(pdes[0]); 91 (void)close(pdes[1]); 92 return (NULL); 93 /* NOTREACHED */ 94 case 0: /* child */ 95 if (pw) { 96 #ifdef LOGIN_CAP 97 if (setusercontext(0, pw, pw->pw_uid, LOGIN_SETALL) < 0) { 98 fprintf(stderr, 99 "setusercontext failed for %s\n", 100 pw->pw_name); 101 _exit(ERROR_EXIT); 102 } 103 #else 104 if (setgid(pw->pw_gid) < 0 || 105 initgroups(pw->pw_name, pw->pw_gid) < 0) { 106 fprintf(stderr, 107 "unable to set groups for %s\n", 108 pw->pw_name); 109 _exit(1); 110 } 111 #if (defined(BSD)) && (BSD >= 199103) 112 setlogin(pw->pw_name); 113 #endif /* BSD */ 114 if (setuid(pw->pw_uid)) { 115 fprintf(stderr, 116 "unable to set uid for %s\n", 117 pw->pw_name); 118 _exit(1); 119 } 120 #endif /* LOGIN_CAP */ 121 } 122 if (*type == 'r') { 123 if (pdes[1] != STDOUT) { 124 dup2(pdes[1], STDOUT); 125 (void)close(pdes[1]); 126 } 127 dup2(STDOUT, STDERR); /* stderr too! */ 128 (void)close(pdes[0]); 129 } else { 130 if (pdes[0] != STDIN) { 131 dup2(pdes[0], STDIN); 132 (void)close(pdes[0]); 133 } 134 (void)close(pdes[1]); 135 } 136 execvp(argv[0], argv); 137 _exit(1); 138 } 139 140 /* parent; assume fdopen can't fail... */ 141 if (*type == 'r') { 142 iop = fdopen(pdes[0], type); 143 (void)close(pdes[1]); 144 } else { 145 iop = fdopen(pdes[1], type); 146 (void)close(pdes[0]); 147 } 148 pids[fileno(iop)] = pid; 149 150 return (iop); 151 } 152 153 int 154 cron_pclose(FILE *iop) { 155 int fdes; 156 PID_T pid; 157 WAIT_T status; 158 sigset_t sigset, osigset; 159 160 /* 161 * pclose returns -1 if stream is not associated with a 162 * `popened' command, or, if already `pclosed'. 163 */ 164 if (pids == 0 || pids[fdes = fileno(iop)] == 0) 165 return (-1); 166 (void)fclose(iop); 167 sigemptyset(&sigset); 168 sigaddset(&sigset, SIGINT); 169 sigaddset(&sigset, SIGQUIT); 170 sigaddset(&sigset, SIGHUP); 171 sigprocmask(SIG_BLOCK, &sigset, &osigset); 172 while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR) 173 continue; 174 sigprocmask(SIG_SETMASK, &osigset, NULL); 175 pids[fdes] = 0; 176 if (pid < 0) 177 return (pid); 178 if (WIFEXITED(status)) 179 return (WEXITSTATUS(status)); 180 return (1); 181 } 182