1 /* $NetBSD: utmp.c,v 1.8 2009/01/11 02:46:27 christos Exp $ */ 2 3 /*- 4 * Copyright (c) 2002 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * This code is derived from software contributed to The NetBSD Foundation 8 * by Christos Zoulas. 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 * 19 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29 * POSSIBILITY OF SUCH DAMAGE. 30 */ 31 32 #include "namespace.h" 33 #include <sys/types.h> 34 #include <sys/param.h> 35 #include <stdio.h> 36 #include <string.h> 37 #include <time.h> 38 #include <utmp.h> 39 #include <sys/stat.h> 40 41 static struct utmp utmp; 42 static FILE *ut; 43 static char utfile[MAXPATHLEN] = _PATH_UTMP; 44 45 void 46 setutent(void) 47 { 48 if (ut == NULL) 49 return; 50 (void)fseeko(ut, (off_t)0, SEEK_SET); 51 } 52 53 struct utmp * 54 getutent(void) 55 { 56 if (ut == NULL) { 57 struct stat st; 58 off_t numentries; 59 if ((ut = fopen(utfile, "r")) == NULL) 60 return NULL; 61 if (fstat(fileno(ut), &st) == -1) 62 goto out; 63 /* 64 * If we have a an old version utmp file bail. 65 */ 66 numentries = st.st_size / sizeof(utmp); 67 if ((off_t)(numentries * sizeof(utmp)) != st.st_size) 68 goto out; 69 } 70 if (fread(&utmp, sizeof(utmp), 1, ut) == 1) 71 return &utmp; 72 out: 73 (void)fclose(ut); 74 return NULL; 75 } 76 77 void 78 endutent(void) 79 { 80 if (ut != NULL) { 81 (void)fclose(ut); 82 ut = NULL; 83 } 84 } 85 86 int 87 utmpname(const char *fname) 88 { 89 size_t len = strlen(fname); 90 91 if (len >= sizeof(utfile)) 92 return 0; 93 94 /* must not end in x! */ 95 if (fname[len - 1] == 'x') 96 return 0; 97 98 (void)strlcpy(utfile, fname, sizeof(utfile)); 99 endutent(); 100 return 1; 101 } 102