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 1.10 2004/03/08 20:31:37 kensmith Exp $ 27 */ 28 29 #include <stdio.h> 30 #include <fcntl.h> 31 #include <stdlib.h> 32 #include <string.h> 33 #include <sys/types.h> 34 #include <sys/stat.h> 35 #include <sys/param.h> 36 #include <errno.h> 37 #include <unistd.h> 38 39 #include "pwupd.h" 40 41 int 42 extendline(char **buf, int * buflen, int needed) 43 { 44 if (needed > *buflen) { 45 char *tmp = realloc(*buf, needed); 46 if (tmp == NULL) 47 return -1; 48 *buf = tmp; 49 *buflen = needed; 50 } 51 return *buflen; 52 } 53 54 int 55 extendarray(char ***buf, int * buflen, int needed) 56 { 57 if (needed > *buflen) { 58 char **tmp = realloc(*buf, needed * sizeof(char *)); 59 if (tmp == NULL) 60 return -1; 61 *buf = tmp; 62 *buflen = needed; 63 } 64 return *buflen; 65 } 66 67 68 int 69 fileupdate(char const * filename, mode_t fmode, char const * newline, char const * prefix, int pfxlen, int updmode) 70 { 71 int rc = 0; 72 73 if (pfxlen <= 1) 74 rc = EINVAL; 75 else { 76 int infd = open(filename, O_RDWR | O_CREAT | O_EXLOCK, fmode); 77 78 if (infd == -1) 79 rc = errno; 80 else { 81 FILE *infp = fdopen(infd, "r+"); 82 83 if (infp == NULL) { 84 rc = errno; /* Assumes fopen(3) sets errno from open(2) */ 85 close(infd); 86 } else { 87 int outfd; 88 char file[MAXPATHLEN]; 89 90 strcpy(file, filename); 91 strcat(file, ".new"); 92 outfd = open(file, O_RDWR | O_CREAT | O_TRUNC, fmode); 93 if (outfd == -1) 94 rc = errno; 95 else { 96 FILE *outfp = fdopen(outfd, "w+"); 97 98 if (outfp == NULL) { 99 rc = errno; 100 close(outfd); 101 } else { 102 int updated = UPD_CREATE; 103 int linesize = PWBUFSZ; 104 char *line = malloc(linesize); 105 106 nextline: 107 while (fgets(line, linesize, infp) != NULL) { 108 char *p = strchr(line, '\n'); 109 110 while ((p = strchr(line, '\n')) == NULL) { 111 int l; 112 if (extendline(&line, &linesize, linesize + PWBUFSZ) == -1) { 113 int ch; 114 fputs(line, outfp); 115 while ((ch = fgetc(infp)) != EOF) { 116 fputc(ch, outfp); 117 if (ch == '\n') 118 break; 119 } 120 goto nextline; 121 } 122 l = strlen(line); 123 if (fgets(line + l, linesize - l, infp) == NULL) 124 break; 125 } 126 if (*line != '#' && *line != '\n') { 127 if (!updated && strncmp(line, prefix, pfxlen) == 0) { 128 updated = updmode == UPD_REPLACE ? UPD_REPLACE : UPD_DELETE; 129 130 /* 131 * Only actually write changes if updating 132 */ 133 if (updmode == UPD_REPLACE) 134 strcpy(line, newline); 135 else if (updmode == UPD_DELETE) 136 continue; 137 } 138 } 139 fputs(line, outfp); 140 } 141 142 /* 143 * Now, we need to decide what to do: If we are in 144 * update mode, and no record was updated, then error If 145 * we are in insert mode, and record already exists, 146 * then error 147 */ 148 if (updmode != updated) 149 /* -1 return means: 150 * update,delete=no user entry 151 * create=entry exists 152 */ 153 rc = -1; 154 else { 155 156 /* 157 * If adding a new record, append it to the end 158 */ 159 if (updmode == UPD_CREATE) 160 fputs(newline, outfp); 161 162 /* 163 * Flush the file and check for the result 164 */ 165 if (fflush(outfp) == EOF) 166 rc = errno; /* Failed to update */ 167 else { 168 /* 169 * Copy data back into the 170 * original file and truncate 171 */ 172 rewind(infp); 173 rewind(outfp); 174 while (fgets(line, linesize, outfp) != NULL) 175 fputs(line, infp); 176 177 /* 178 * If there was a problem with copying 179 * we will just rename 'file.new' 180 * to 'file'. 181 * This is a gross hack, but we may have 182 * corrupted the original file 183 */ 184 if (fflush(infp) == EOF || ferror(infp)) 185 rename(file, filename); 186 else 187 ftruncate(infd, ftell(infp)); 188 } 189 } 190 free(line); 191 fclose(outfp); 192 } 193 remove(file); 194 } 195 fclose(infp); 196 } 197 } 198 } 199 return rc; 200 } 201