summaryrefslogtreecommitdiffstats
path: root/lib/dpkg/db-fsys-override.c
blob: e079c5ffbbcb5f2234ed2519f843d8d7f6a59b86 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
/*
 * libdpkg - Debian packaging suite library routines
 * db-fsys-override.c - management of filesystem stat overrides database
 *
 * Copyright © 1995 Ian Jackson <ijackson@chiark.greenend.org.uk>
 * Copyright © 2000, 2001 Wichert Akkerman <wakkerma@debian.org>
 * Copyright © 2008-2012 Guillem Jover <guillem@debian.org>
 *
 * This is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

#include <config.h>
#include <compat.h>

#include <sys/types.h>
#include <sys/stat.h>

#include <errno.h>
#include <string.h>
#include <pwd.h>
#include <grp.h>
#include <fcntl.h>
#include <unistd.h>
#include <stdlib.h>

#include <dpkg/i18n.h>
#include <dpkg/dpkg.h>
#include <dpkg/dpkg-db.h>
#include <dpkg/fdio.h>
#include <dpkg/debug.h>
#include <dpkg/db-fsys.h>

static char *statoverridename;

uid_t
statdb_parse_uid(const char *str)
{
	char *endptr;
	uid_t uid;

	if (str[0] == '#') {
		long int value;

		errno = 0;
		value = strtol(str + 1, &endptr, 10);
		if (str + 1 == endptr || *endptr || value < 0 || errno != 0)
			ohshit(_("invalid statoverride uid %s"), str);
		uid = (uid_t)value;
	} else {
		struct passwd *pw = getpwnam(str);

		if (pw == NULL)
			uid = (uid_t)-1;
		else
			uid = pw->pw_uid;
	}

	return uid;
}

gid_t
statdb_parse_gid(const char *str)
{
	char *endptr;
	gid_t gid;

	if (str[0] == '#') {
		long int value;

		errno = 0;
		value = strtol(str + 1, &endptr, 10);
		if (str + 1 == endptr || *endptr || value < 0 || errno != 0)
			ohshit(_("invalid statoverride gid %s"), str);
		gid = (gid_t)value;
	} else {
		struct group *gr = getgrnam(str);

		if (gr == NULL)
			gid = (gid_t)-1;
		else
			gid = gr->gr_gid;
	}

	return gid;
}

mode_t
statdb_parse_mode(const char *str)
{
	char *endptr;
	long int mode;

	mode = strtol(str, &endptr, 8);
	if (str == endptr || *endptr || mode < 0 || mode > 07777)
		ohshit(_("invalid statoverride mode %s"), str);

	return (mode_t)mode;
}

void
ensure_statoverrides(enum statdb_parse_flags flags)
{
	static struct stat sb_prev;
	struct stat sb_next;
	static FILE *file_prev;
	FILE *file;
	char *loaded_list, *loaded_list_end, *thisline, *nextline, *ptr;
	struct file_stat *fso;
	struct fsys_namenode *fnn;
	struct fsys_hash_iter *iter;

	if (statoverridename == NULL)
		statoverridename = dpkg_db_get_path(STATOVERRIDEFILE);

	onerr_abort++;

	file = fopen(statoverridename, "r");
	if (!file) {
		if (errno != ENOENT)
			ohshite(_("failed to open statoverride file"));
	} else {
		setcloexec(fileno(file), statoverridename);

		if (fstat(fileno(file), &sb_next))
			ohshite(_("failed to fstat statoverride file"));

		/*
		 * We need to keep the database file open so that the
		 * filesystem cannot reuse the inode number (f.ex. during
		 * multiple dpkg-statoverride invocations in a maintainer
		 * script), otherwise the following check might turn true,
		 * and we would skip reloading a modified database.
		 */
		if (file_prev &&
		    sb_prev.st_dev == sb_next.st_dev &&
		    sb_prev.st_ino == sb_next.st_ino) {
			fclose(file);
			onerr_abort--;
			debug(dbg_general, "%s: same, skipping", __func__);
			return;
		}
		sb_prev = sb_next;
	}
	if (file_prev)
		fclose(file_prev);
	file_prev = file;

	/* Reset statoverride information. */
	iter = fsys_hash_iter_new();
	while ((fnn = fsys_hash_iter_next(iter)))
		fnn->statoverride = NULL;
	fsys_hash_iter_free(iter);

	if (!file) {
		onerr_abort--;
		debug(dbg_general, "%s: none, resetting", __func__);
		return;
	}
	debug(dbg_general, "%s: new, (re)loading", __func__);

	/* If the statoverride list is empty we don't need to bother
	 * reading it. */
	if (!sb_next.st_size) {
		onerr_abort--;
		return;
	}

	loaded_list = m_malloc(sb_next.st_size);
	loaded_list_end = loaded_list + sb_next.st_size;

	if (fd_read(fileno(file), loaded_list, sb_next.st_size) < 0)
		ohshite(_("reading statoverride file '%.250s'"), statoverridename);

	thisline = loaded_list;
	while (thisline < loaded_list_end) {
		fso = nfmalloc(sizeof(*fso));

		ptr = memchr(thisline, '\n', loaded_list_end - thisline);
		if (ptr == NULL)
			ohshit(_("statoverride file is missing final newline"));
		/* Where to start next time around. */
		nextline = ptr + 1;
		if (ptr == thisline)
			ohshit(_("statoverride file contains empty line"));
		*ptr = '\0';

		/* Extract the uid. */
		ptr = memchr(thisline, ' ', nextline - thisline);
		if (ptr == NULL)
			ohshit(_("syntax error in statoverride file"));
		*ptr = '\0';

		fso->uid = statdb_parse_uid(thisline);
		if (fso->uid == (uid_t)-1)
			fso->uname = nfstrsave(thisline);
		else
			fso->uname = NULL;

		if (fso->uid == (uid_t)-1 && !(flags & STATDB_PARSE_LAX))
			ohshit(_("unknown system user '%s' in statoverride file; the system user got removed\n"
			         "before the override, which is most probably a packaging bug, to recover you\n"
			         "can remove the override manually with %s"), thisline, DPKGSTAT);

		/* Move to the next bit */
		thisline = ptr + 1;
		if (thisline >= loaded_list_end)
			ohshit(_("unexpected end of line in statoverride file"));

		/* Extract the gid */
		ptr = memchr(thisline, ' ', nextline - thisline);
		if (ptr == NULL)
			ohshit(_("syntax error in statoverride file"));
		*ptr = '\0';

		fso->gid = statdb_parse_gid(thisline);
		if (fso->gid == (gid_t)-1)
			fso->gname = nfstrsave(thisline);
		else
			fso->gname = NULL;

		if (fso->gid == (gid_t)-1 && !(flags & STATDB_PARSE_LAX))
			ohshit(_("unknown system group '%s' in statoverride file; the system group got removed\n"
			         "before the override, which is most probably a packaging bug, to recover you\n"
			         "can remove the override manually with %s"), thisline, DPKGSTAT);

		/* Move to the next bit */
		thisline = ptr + 1;
		if (thisline >= loaded_list_end)
			ohshit(_("unexpected end of line in statoverride file"));

		/* Extract the mode */
		ptr = memchr(thisline, ' ', nextline - thisline);
		if (ptr == NULL)
			ohshit(_("syntax error in statoverride file"));
		*ptr = '\0';

		fso->mode = statdb_parse_mode(thisline);

		/* Move to the next bit */
		thisline = ptr + 1;
		if (thisline >= loaded_list_end)
			ohshit(_("unexpected end of line in statoverride file"));

		fnn = fsys_hash_find_node(thisline, 0);
		if (fnn->statoverride)
			ohshit(_("multiple statoverrides present for file '%.250s'"),
			       thisline);
		fnn->statoverride = fso;

		/* Moving on... */
		thisline = nextline;
	}

	free(loaded_list);

	onerr_abort--;
}