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
27#ifndef lint
28static const char rcsid[] =
29  "$FreeBSD$";
30#endif /* not lint */
31
32#include <stdio.h>
33#include <fcntl.h>
34#include <stdlib.h>
35#include <string.h>
36#include <sys/types.h>
37#include <sys/stat.h>
38#include <sys/param.h>
39#include <errno.h>
40#include <unistd.h>
41
42#include "pwupd.h"
43
44int
45extendline(char **buf, int * buflen, int needed)
46{
47	if (needed > *buflen) {
48		char	*tmp = realloc(*buf, needed);
49		if (tmp == NULL)
50			return -1;
51		*buf = tmp;
52		*buflen = needed;
53	}
54	return *buflen;
55}
56
57int
58extendarray(char ***buf, int * buflen, int needed)
59{
60	if (needed > *buflen) {
61		char	**tmp = realloc(*buf, needed * sizeof(char *));
62		if (tmp == NULL)
63			return -1;
64		*buf = tmp;
65		*buflen = needed;
66	}
67	return *buflen;
68}
69
70
71int
72fileupdate(char const * filename, mode_t fmode, char const * newline, char const * prefix, int pfxlen, int updmode)
73{
74	int     rc = 0;
75
76	if (pfxlen <= 1)
77		rc = EINVAL;
78	else {
79		int    infd = open(filename, O_RDWR | O_CREAT | O_EXLOCK, fmode);
80
81		if (infd == -1)
82			rc = errno;
83		else {
84			FILE   *infp = fdopen(infd, "r+");
85
86			if (infp == NULL) {
87				rc = errno;		/* Assumes fopen(3) sets errno from open(2) */
88				close(infd);
89			} else {
90				int       outfd;
91				char      file[MAXPATHLEN];
92
93				strcpy(file, filename);
94				strcat(file, ".new");
95				outfd = open(file, O_RDWR | O_CREAT | O_TRUNC, fmode);
96				if (outfd == -1)
97					rc = errno;
98				else {
99					FILE    *outfp = fdopen(outfd, "w+");
100
101					if (outfp == NULL) {
102						rc = errno;
103						close(outfd);
104					} else {
105						int   updated = UPD_CREATE;
106						int		linesize = PWBUFSZ;
107						char  *line = malloc(linesize);
108
109					nextline:
110						while (fgets(line, linesize, infp) != NULL) {
111							char  *p = strchr(line, '\n');
112
113							while ((p = strchr(line, '\n')) == NULL) {
114								int	l;
115								if (extendline(&line, &linesize, linesize + PWBUFSZ) == -1) {
116									int	ch;
117									fputs(line, outfp);
118									while ((ch = fgetc(infp)) != EOF) {
119										fputc(ch, outfp);
120										if (ch == '\n')
121											break;
122									}
123									goto nextline;
124								}
125								l = strlen(line);
126								if (fgets(line + l, linesize - l, infp) == NULL)
127									break;
128							}
129							if (*line != '#' && *line != '\n') {
130								if (!updated && strncmp(line, prefix, pfxlen) == 0) {
131									updated = updmode == UPD_REPLACE ? UPD_REPLACE : UPD_DELETE;
132
133									/*
134									 * Only actually write changes if updating
135									 */
136									if (updmode == UPD_REPLACE)
137										strcpy(line, newline);
138									else if (updmode == UPD_DELETE)
139										continue;
140								}
141							}
142							fputs(line, outfp);
143						}
144
145						/*
146						 * Now, we need to decide what to do: If we are in
147						 * update mode, and no record was updated, then error If
148						 * we are in insert mode, and record already exists,
149						 * then error
150						 */
151						if (updmode != updated)
152							/* -1 return means:
153							 * update,delete=no user entry
154							 * create=entry exists
155							 */
156							rc = -1;
157						else {
158
159							/*
160							 * If adding a new record, append it to the end
161							 */
162							if (updmode == UPD_CREATE)
163								fputs(newline, outfp);
164
165							/*
166							 * Flush the file and check for the result
167							 */
168							if (fflush(outfp) == EOF)
169								rc = errno;	/* Failed to update */
170							else {
171								/*
172								 * Copy data back into the
173								 * original file and truncate
174								 */
175								rewind(infp);
176								rewind(outfp);
177								while (fgets(line, linesize, outfp) != NULL)
178									fputs(line, infp);
179
180								/*
181								 * If there was a problem with copying
182								 * we will just rename 'file.new'
183								 * to 'file'.
184								 * This is a gross hack, but we may have
185								 * corrupted the original file
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