1 /* $OpenBSD: popen.c,v 1.21 2009/10/27 23:59:51 deraadt 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 #include "cron.h" 41 42 #define MAX_ARGV 100 43 #define MAX_GARGV 1000 44 45 /* 46 * Special version of popen which avoids call to shell. This ensures noone 47 * may create a pipe to a hidden program as a side effect of a list or dir 48 * command. 49 */ 50 static PID_T *pids; 51 static int fds; 52 53 FILE * 54 cron_popen(char *program, char *type, struct passwd *pw) { 55 char *cp; 56 FILE *iop; 57 int argc, pdes[2]; 58 PID_T pid; 59 char *argv[MAX_ARGV]; 60 61 if ((*type != 'r' && *type != 'w') || type[1] != '\0') 62 return (NULL); 63 64 if (!pids) { 65 if ((fds = sysconf(_SC_OPEN_MAX)) <= 0) 66 return (NULL); 67 if (!(pids = calloc(fds, sizeof(PID_T)))) 68 return (NULL); 69 } 70 if (pipe(pdes) < 0) 71 return (NULL); 72 73 /* break up string into pieces */ 74 for (argc = 0, cp = program; argc < MAX_ARGV - 1; cp = NULL) 75 if (!(argv[argc++] = strtok(cp, " \t\n"))) 76 break; 77 argv[MAX_ARGV-1] = NULL; 78 79 switch (pid = fork()) { 80 case -1: /* error */ 81 (void)close(pdes[0]); 82 (void)close(pdes[1]); 83 return (NULL); 84 /* NOTREACHED */ 85 case 0: /* child */ 86 if (pw) { 87 #ifdef LOGIN_CAP 88 if (setusercontext(0, pw, pw->pw_uid, LOGIN_SETALL) < 0) { 89 fprintf(stderr, 90 "setusercontext failed for %s\n", 91 pw->pw_name); 92 _exit(ERROR_EXIT); 93 } 94 #else 95 if (setgid(pw->pw_gid) < 0 || 96 initgroups(pw->pw_name, pw->pw_gid) < 0) { 97 fprintf(stderr, 98 "unable to set groups for %s\n", 99 pw->pw_name); 100 _exit(1); 101 } 102 #if (defined(BSD)) && (BSD >= 199103) 103 setlogin(pw->pw_name); 104 #endif /* BSD */ 105 if (setuid(pw->pw_uid)) { 106 fprintf(stderr, 107 "unable to set uid for %s\n", 108 pw->pw_name); 109 _exit(1); 110 } 111 #endif /* LOGIN_CAP */ 112 } 113 if (*type == 'r') { 114 if (pdes[1] != STDOUT) { 115 dup2(pdes[1], STDOUT); 116 (void)close(pdes[1]); 117 } 118 dup2(STDOUT, STDERR); /* stderr too! */ 119 (void)close(pdes[0]); 120 } else { 121 if (pdes[0] != STDIN) { 122 dup2(pdes[0], STDIN); 123 (void)close(pdes[0]); 124 } 125 (void)close(pdes[1]); 126 } 127 execvp(argv[0], argv); 128 _exit(1); 129 } 130 131 /* parent; assume fdopen can't fail... */ 132 if (*type == 'r') { 133 iop = fdopen(pdes[0], type); 134 (void)close(pdes[1]); 135 } else { 136 iop = fdopen(pdes[1], type); 137 (void)close(pdes[0]); 138 } 139 pids[fileno(iop)] = pid; 140 141 return (iop); 142 } 143 144 int 145 cron_pclose(FILE *iop) { 146 int fdes; 147 PID_T pid; 148 WAIT_T status; 149 sigset_t sigset, osigset; 150 151 /* 152 * pclose returns -1 if stream is not associated with a 153 * `popened' command, or, if already `pclosed'. 154 */ 155 if (pids == 0 || pids[fdes = fileno(iop)] == 0) 156 return (-1); 157 (void)fclose(iop); 158 sigemptyset(&sigset); 159 sigaddset(&sigset, SIGINT); 160 sigaddset(&sigset, SIGQUIT); 161 sigaddset(&sigset, SIGHUP); 162 sigprocmask(SIG_BLOCK, &sigset, &osigset); 163 while ((pid = waitpid(pids[fdes], &status, 0)) < 0 && errno == EINTR) 164 continue; 165 sigprocmask(SIG_SETMASK, &osigset, NULL); 166 pids[fdes] = 0; 167 if (pid < 0) 168 return (pid); 169 if (WIFEXITED(status)) 170 return (WEXITSTATUS(status)); 171 return (1); 172 } 173