1 /*- 2 * Copyright (C) 1996 3 * David L. Nugent. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY DAVID L. NUGENT AND CONTRIBUTORS ``AS IS'' AND 15 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 16 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 17 * ARE DISCLAIMED. IN NO EVENT SHALL DAVID L. NUGENT OR CONTRIBUTORS BE LIABLE 18 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 19 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 20 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 21 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 22 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 23 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 24 * SUCH DAMAGE. 25 * 26 * $FreeBSD: src/usr.sbin/pw/fileupd.c,v 1.9 1999/10/26 04:27:13 davidn Exp $ 27 * $DragonFly: src/usr.sbin/pw/fileupd.c,v 1.2 2003/06/17 04:30:01 dillon Exp $ 28 */ 29 30 #include <stdio.h> 31 #include <fcntl.h> 32 #include <stdlib.h> 33 #include <string.h> 34 #include <sys/types.h> 35 #include <sys/stat.h> 36 #include <sys/param.h> 37 #include <errno.h> 38 #include <unistd.h> 39 40 #include "pwupd.h" 41 42 int 43 extendline(char **buf, int * buflen, int needed) 44 { 45 if (needed > *buflen) { 46 char *tmp = realloc(*buf, needed); 47 if (tmp == NULL) 48 return -1; 49 *buf = tmp; 50 *buflen = needed; 51 } 52 return *buflen; 53 } 54 55 int 56 extendarray(char ***buf, int * buflen, int needed) 57 { 58 if (needed > *buflen) { 59 char **tmp = realloc(*buf, needed * sizeof(char *)); 60 if (tmp == NULL) 61 return -1; 62 *buf = tmp; 63 *buflen = needed; 64 } 65 return *buflen; 66 } 67 68 69 int 70 fileupdate(char const * filename, mode_t fmode, char const * newline, char const * prefix, int pfxlen, int updmode) 71 { 72 int rc = 0; 73 74 if (pfxlen <= 1) 75 rc = EINVAL; 76 else { 77 int infd = open(filename, O_RDWR | O_CREAT, fmode); 78 79 if (infd == -1) 80 rc = errno; 81 else { 82 FILE *infp = fdopen(infd, "r+"); 83 84 if (infp == NULL) { 85 rc = errno; /* Assumes fopen(3) sets errno from open(2) */ 86 close(infd); 87 } else { 88 int outfd; 89 char file[MAXPATHLEN]; 90 91 strcpy(file, filename); 92 strcat(file, ".new"); 93 outfd = open(file, O_RDWR | O_CREAT | O_TRUNC | O_EXLOCK, fmode); 94 if (outfd == -1) 95 rc = errno; 96 else { 97 FILE *outfp = fdopen(outfd, "w+"); 98 99 if (outfp == NULL) { 100 rc = errno; 101 close(outfd); 102 } else { 103 int updated = UPD_CREATE; 104 int linesize = PWBUFSZ; 105 char *line = malloc(linesize); 106 107 nextline: 108 while (fgets(line, linesize, infp) != NULL) { 109 char *p = strchr(line, '\n'); 110 111 while ((p = strchr(line, '\n')) == NULL) { 112 int l; 113 if (extendline(&line, &linesize, linesize + PWBUFSZ) == -1) { 114 int ch; 115 fputs(line, outfp); 116 while ((ch = fgetc(infp)) != EOF) { 117 fputc(ch, outfp); 118 if (ch == '\n') 119 break; 120 } 121 goto nextline; 122 } 123 l = strlen(line); 124 if (fgets(line + l, linesize - l, infp) == NULL) 125 break; 126 } 127 if (*line != '#' && *line != '\n') { 128 if (!updated && strncmp(line, prefix, pfxlen) == 0) { 129 updated = updmode == UPD_REPLACE ? UPD_REPLACE : UPD_DELETE; 130 131 /* 132 * Only actually write changes if updating 133 */ 134 if (updmode == UPD_REPLACE) 135 strcpy(line, newline); 136 else if (updmode == UPD_DELETE) 137 continue; 138 } 139 } 140 fputs(line, outfp); 141 } 142 143 /* 144 * Now, we need to decide what to do: If we are in 145 * update mode, and no record was updated, then error If 146 * we are in insert mode, and record already exists, 147 * then error 148 */ 149 if (updmode != updated) 150 /* -1 return means: 151 * update,delete=no user entry 152 * create=entry exists 153 */ 154 rc = -1; 155 else { 156 157 /* 158 * If adding a new record, append it to the end 159 */ 160 if (updmode == UPD_CREATE) 161 fputs(newline, outfp); 162 163 /* 164 * Flush the file and check for the result 165 */ 166 if (fflush(outfp) == EOF) 167 rc = errno; /* Failed to update */ 168 else { 169 /* 170 * Copy data back into the 171 * original file and truncate 172 */ 173 rewind(infp); 174 rewind(outfp); 175 while (fgets(line, linesize, outfp) != NULL) 176 fputs(line, infp); 177 178 /* 179 * If there was a problem with copying 180 * we will just rename 'file.new' 181 * to 'file'. 182 * This is a gross hack, but we may have 183 * corrupted the original file 184 * Unfortunately, it will lose the inode 185 * and hence the lock. 186 */ 187 if (fflush(infp) == EOF || ferror(infp)) 188 rename(file, filename); 189 else 190 ftruncate(infd, ftell(infp)); 191 } 192 } 193 free(line); 194 fclose(outfp); 195 } 196 remove(file); 197 } 198 fclose(infp); 199 } 200 } 201 } 202 return rc; 203 } 204