3 * David L. Nugent. All rights reserved.
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions
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.
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
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 $
34 #include <sys/types.h>
36 #include <sys/param.h>
43 extendline(char **buf, int * buflen, int needed)
45 if (needed > *buflen) {
46 char *tmp = realloc(*buf, needed);
56 extendarray(char ***buf, int * buflen, int needed)
58 if (needed > *buflen) {
59 char **tmp = realloc(*buf, needed * sizeof(char *));
70 fileupdate(char const * filename, mode_t fmode, char const * newline, char const * prefix, int pfxlen, int updmode)
77 int infd = open(filename, O_RDWR | O_CREAT, fmode);
82 FILE *infp = fdopen(infd, "r+");
85 rc = errno; /* Assumes fopen(3) sets errno from open(2) */
89 char file[MAXPATHLEN];
91 strcpy(file, filename);
93 outfd = open(file, O_RDWR | O_CREAT | O_TRUNC | O_EXLOCK, fmode);
97 FILE *outfp = fdopen(outfd, "w+");
103 int updated = UPD_CREATE;
104 int linesize = PWBUFSZ;
105 char *line = malloc(linesize);
108 while (fgets(line, linesize, infp) != NULL) {
109 char *p = strchr(line, '\n');
111 while ((p = strchr(line, '\n')) == NULL) {
113 if (extendline(&line, &linesize, linesize + PWBUFSZ) == -1) {
116 while ((ch = fgetc(infp)) != EOF) {
124 if (fgets(line + l, linesize - l, infp) == NULL)
127 if (*line != '#' && *line != '\n') {
128 if (!updated && strncmp(line, prefix, pfxlen) == 0) {
129 updated = updmode == UPD_REPLACE ? UPD_REPLACE : UPD_DELETE;
132 * Only actually write changes if updating
134 if (updmode == UPD_REPLACE)
135 strcpy(line, newline);
136 else if (updmode == UPD_DELETE)
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,
149 if (updmode != updated)
151 * update,delete=no user entry
152 * create=entry exists
158 * If adding a new record, append it to the end
160 if (updmode == UPD_CREATE)
161 fputs(newline, outfp);
164 * Flush the file and check for the result
166 if (fflush(outfp) == EOF)
167 rc = errno; /* Failed to update */
170 * Copy data back into the
171 * original file and truncate
175 while (fgets(line, linesize, outfp) != NULL)
179 * If there was a problem with copying
180 * we will just rename 'file.new'
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.
187 if (fflush(infp) == EOF || ferror(infp))
188 rename(file, filename);
190 ftruncate(infd, ftell(infp));