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 27#if 0 28static char sccsid[] = "@(#)popen.c 5.7 (Berkeley) 2/14/89"; 29#endif 30static const char rcsid[] = 31 "$FreeBSD: stable/11/usr.sbin/cron/cron/popen.c 358255 2020-02-23 03:13:38Z kevans $"; 32#endif /* not lint */ 33 34#include "cron.h" 35#include <sys/signal.h> 36#include <fcntl.h> 37#include <paths.h> 38#if defined(SYSLOG) 39# include <syslog.h> 40#endif 41#if defined(LOGIN_CAP) 42# include <login_cap.h> 43#endif 44 45 46#define MAX_ARGS 100 47#define WANT_GLOBBING 0 48 49/* 50 * Special version of popen which avoids call to shell. This insures no one 51 * may create a pipe to a hidden program as a side effect of a list or dir 52 * command. 53 */ 54static PID_T *pids; 55static int fds; 56 57FILE * 58cron_popen(program, type, e, pidptr) 59 char *program, *type; 60 entry *e; 61 PID_T *pidptr; 62{ 63 register char *cp; 64 FILE *iop; 65 int argc, pdes[2]; 66 PID_T pid; 67 char *usernm; 68 char *argv[MAX_ARGS + 1]; 69# if defined(LOGIN_CAP) 70 struct passwd *pwd; 71 login_cap_t *lc; 72# endif 73#if WANT_GLOBBING 74 char **pop, *vv[2]; 75 int gargc; 76 char *gargv[1000]; 77 extern char **glob(), **copyblk(); 78#endif 79 80 if ((*type != 'r' && *type != 'w') || type[1]) 81 return(NULL); 82 83 if (!pids) { 84 if ((fds = getdtablesize()) <= 0) 85 return(NULL); 86 if (!(pids = calloc(fds, sizeof(PID_T)))) 87 return(NULL); 88 } 89 if (pipe(pdes) < 0) 90 return(NULL); 91 92 /* break up string into pieces */ 93 for (argc = 0, cp = program; argc < MAX_ARGS; cp = NULL) 94 if (!(argv[argc++] = strtok(cp, " \t\n"))) 95 break; 96 argv[MAX_ARGS] = NULL; 97 98#if WANT_GLOBBING 99 /* glob each piece */ 100 gargv[0] = argv[0]; 101 for (gargc = argc = 1; argv[argc]; argc++) { 102 if (!(pop = glob(argv[argc]))) { /* globbing failed */ 103 vv[0] = argv[argc]; 104 vv[1] = NULL; 105 pop = copyblk(vv); 106 } 107 argv[argc] = (char *)pop; /* save to free later */ 108 while (*pop && gargc < 1000) 109 gargv[gargc++] = *pop++; 110 } 111 gargv[gargc] = NULL; 112#endif 113 114 iop = NULL; 115 switch(pid = fork()) { 116 case -1: /* error */ 117 (void)close(pdes[0]); 118 (void)close(pdes[1]); 119 goto pfree; 120 /* NOTREACHED */ 121 case 0: /* child */ 122 if (e != NULL) { 123#ifdef SYSLOG 124 closelog(); 125#endif 126 127 /* get new pgrp, void tty, etc. 128 */ 129 (void) setsid(); 130 } 131 if (*type == 'r') { 132 /* Do not share our parent's stdin */ 133 (void)close(0); 134 (void)open(_PATH_DEVNULL, O_RDWR); 135 if (pdes[1] != 1) { 136 dup2(pdes[1], 1); 137 dup2(pdes[1], 2); /* stderr, too! */ 138 (void)close(pdes[1]); 139 } 140 (void)close(pdes[0]); 141 } else { 142 if (pdes[0] != 0) { 143 dup2(pdes[0], 0); 144 (void)close(pdes[0]); 145 } 146 /* Hack: stdout gets revoked */ 147 (void)close(1); 148 (void)open(_PATH_DEVNULL, O_RDWR); 149 (void)close(2); 150 (void)open(_PATH_DEVNULL, O_RDWR); 151 (void)close(pdes[1]); 152 } 153 if (e != NULL) { 154 /* Set user's entire context, but skip the environment 155 * as cron provides a separate interface for this 156 */ 157 usernm = env_get("LOGNAME", e->envp); 158# if defined(LOGIN_CAP) 159 if ((pwd = getpwnam(usernm)) == NULL) 160 pwd = getpwuid(e->uid); 161 lc = NULL; 162 if (pwd != NULL) { 163 pwd->pw_gid = e->gid; 164 if (e->class != NULL) 165 lc = login_getclass(e->class); 166 } 167 if (pwd && 168 setusercontext(lc, pwd, e->uid, 169 LOGIN_SETALL & ~(LOGIN_SETPATH|LOGIN_SETENV)) == 0) 170 (void) endpwent(); 171 else { 172 /* fall back to the old method */ 173 (void) endpwent(); 174# endif 175 /* 176 * Set our directory, uid and gid. Set gid 177 * first since once we set uid, we've lost 178 * root privileges. 179 */ 180 if (setgid(e->gid) != 0) 181 _exit(ERROR_EXIT); 182# if defined(BSD) 183 if (initgroups(usernm, e->gid) != 0) 184 _exit(ERROR_EXIT); 185# endif 186 if (setlogin(usernm) != 0) 187 _exit(ERROR_EXIT); 188 if (setuid(e->uid) != 0) 189 _exit(ERROR_EXIT); 190 /* we aren't root after this..*/ 191#if defined(LOGIN_CAP) 192 } 193 if (lc != NULL) 194 login_close(lc); 195#endif 196 chdir(env_get("HOME", e->envp)); 197 } 198#if WANT_GLOBBING 199 execvp(gargv[0], gargv); 200#else 201 execvp(argv[0], argv); 202#endif 203 _exit(1); 204 } 205 /* parent; assume fdopen can't fail... */ 206 if (*type == 'r') { 207 iop = fdopen(pdes[0], type); 208 (void)close(pdes[1]); 209 } else { 210 iop = fdopen(pdes[1], type); 211 (void)close(pdes[0]); 212 } 213 pids[fileno(iop)] = pid; 214 215pfree: 216#if WANT_GLOBBING 217 for (argc = 1; argv[argc] != NULL; argc++) { 218/* blkfree((char **)argv[argc]); */ 219 free((char *)argv[argc]); 220 } 221#endif 222 223 *pidptr = pid; 224 225 return(iop); 226} 227 228int 229cron_pclose(iop) 230 FILE *iop; 231{ 232 register int fdes; 233 int omask; 234 WAIT_T stat_loc; 235 PID_T pid; 236 237 /* 238 * pclose returns -1 if stream is not associated with a 239 * `popened' command, or, if already `pclosed'. 240 */ 241 if (pids == 0 || pids[fdes = fileno(iop)] == 0) 242 return(-1); 243 (void)fclose(iop); 244 omask = sigblock(sigmask(SIGINT)|sigmask(SIGQUIT)|sigmask(SIGHUP)); 245 while ((pid = wait(&stat_loc)) != pids[fdes] && pid != -1) 246 ; 247 (void)sigsetmask(omask); 248 pids[fdes] = 0; 249 return (pid == -1 ? -1 : WEXITSTATUS(stat_loc)); 250} 251