1 /* $OpenBSD: locking.c,v 1.15 2020/05/27 03:12:06 millert Exp $ */ 2 3 /* 4 * Copyright (c) 1996-1998 Theo de Raadt <deraadt@theos.com> 5 * Copyright (c) 1996-1998 David Mazieres <dm@lcs.mit.edu> 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 * 3. The name of the authors may not be used to endorse or promote products 17 * derived from this software without specific prior written permission. 18 * 19 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, 20 * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY 21 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL 22 * THE AUTHORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 23 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 24 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 25 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 26 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 27 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 28 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 29 */ 30 31 #include <sys/types.h> 32 #include <sys/stat.h> 33 #include <fcntl.h> 34 #include <pwd.h> 35 #include <syslog.h> 36 #include <unistd.h> 37 #include <limits.h> 38 #include <errno.h> 39 #include <stdio.h> 40 #include <stdlib.h> 41 #include <string.h> 42 #include <stdarg.h> 43 #include "pathnames.h" 44 #include "mail.local.h" 45 46 static char lpath[PATH_MAX]; 47 48 void 49 rellock(void) 50 { 51 52 if (lpath[0]) 53 unlink(lpath); 54 } 55 56 int 57 getlock(const char *name, struct passwd *pw) 58 { 59 struct stat sb; 60 int lfd=-1; 61 int tries = 0; 62 63 (void)snprintf(lpath, sizeof lpath, "%s/%s.lock", 64 _PATH_MAILDIR, name); 65 66 if (stat(_PATH_MAILDIR, &sb) != -1 && 67 (sb.st_mode & S_IWOTH) == S_IWOTH) { 68 mwarn("%s: will not deliver to world-writable spool", 69 _PATH_MAILDIR); 70 } else { 71 /* 72 * Only root can write the spool directory. 73 */ 74 while (1) { 75 if ((lfd = open(lpath, O_CREAT|O_WRONLY|O_EXCL, 76 S_IRUSR|S_IWUSR)) != -1) 77 break; 78 if (tries > 9) { 79 mwarn("%s: %s", lpath, strerror(errno)); 80 return(-1); 81 } 82 sleep(1U << tries); 83 tries++; 84 } 85 } 86 return(lfd); 87 } 88 89 void 90 mwarn(const char *fmt, ...) 91 { 92 va_list ap; 93 94 va_start(ap, fmt); 95 vsyslog(LOG_ERR, fmt, ap); 96 va_end(ap); 97 } 98 99 void 100 merr(int eval, const char *fmt, ...) 101 { 102 va_list ap; 103 104 va_start(ap, fmt); 105 vsyslog(LOG_ERR, fmt, ap); 106 va_end(ap); 107 exit(eval); 108 } 109