1 /* $OpenBSD: lockspool.c,v 1.23 2023/03/08 04:43:05 guenther Exp $ */ 2 3 /* 4 * Copyright (c) 1998 Theo de Raadt <deraadt@theos.com> 5 * Copyright (c) 1998 Todd C. Miller <millert@openbsd.org> 6 * All rights reserved. 7 * 8 * Redistribution and use in source and binary forms, with or without 9 * modification, are permitted provided that the following conditions 10 * are met: 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in the 15 * documentation and/or other materials provided with the distribution. 16 * 17 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 18 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 19 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 20 * THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 21 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 22 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 23 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 24 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 25 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 26 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #include <signal.h> 30 #include <pwd.h> 31 #include <syslog.h> 32 #include <unistd.h> 33 #include <errno.h> 34 #include <stdio.h> 35 #include <paths.h> 36 #include <stdlib.h> 37 #include <poll.h> 38 #include <err.h> 39 40 #include "mail.local.h" 41 42 void unhold(int); 43 void usage(void); 44 45 extern char *__progname; 46 47 int 48 main(int argc, char *argv[]) 49 { 50 struct passwd *pw; 51 struct pollfd pfd; 52 ssize_t nread; 53 char *from, c; 54 int holdfd; 55 56 if (unveil(_PATH_MAILDIR, "rwc") == -1) 57 err(1, "unveil %s", _PATH_MAILDIR); 58 if (pledge("stdio rpath wpath getpw cpath fattr", NULL) == -1) 59 err(1, "pledge"); 60 61 openlog(__progname, LOG_PERROR, LOG_MAIL); 62 63 if (argc != 1 && argc != 2) 64 usage(); 65 if (argc == 2 && getuid() != 0) 66 merr(1, "you must be root to lock someone else's spool"); 67 68 signal(SIGTERM, unhold); 69 signal(SIGINT, unhold); 70 signal(SIGHUP, unhold); 71 signal(SIGPIPE, unhold); 72 73 if (argc == 2) 74 pw = getpwnam(argv[1]); 75 else 76 pw = getpwuid(getuid()); 77 if (pw == NULL) 78 exit (1); 79 from = pw->pw_name; 80 81 holdfd = getlock(from, pw); 82 if (holdfd == -1) { 83 write(STDOUT_FILENO, "0\n", 2); 84 exit (1); 85 } 86 write(STDOUT_FILENO, "1\n", 2); 87 88 /* wait for the other end of the pipe to close, then release the lock */ 89 pfd.fd = STDIN_FILENO; 90 pfd.events = POLLIN; 91 do { 92 if (poll(&pfd, 1, INFTIM) == -1) { 93 if (errno != EINTR) 94 break; 95 } 96 do { 97 nread = read(STDIN_FILENO, &c, 1); 98 } while (nread == 1 || (nread == -1 && errno == EINTR)); 99 } while (nread == -1 && errno == EAGAIN); 100 rellock(); 101 exit (0); 102 } 103 104 void 105 unhold(int signo) 106 { 107 108 rellock(); 109 _exit(0); 110 } 111 112 void 113 usage(void) 114 { 115 116 merr(1, "usage: %s [username]", __progname); 117 } 118