summaryrefslogtreecommitdiffstats
path: root/src/filters.c
blob: f770fb74c1a706803a0149345b6e3363a0b37b8e (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
/*
 * dpkg - main program for package management
 * filters.c - filtering routines for excluding bits of packages
 *
 * Copyright © 2007, 2008 Tollef Fog Heen <tfheen@err.no>
 * Copyright © 2008, 2010, 2012-2014 Guillem Jover <guillem@debian.org>
 * Copyright © 2010 Canonical Ltd.
 *   written by Martin Pitt <martin.pitt@canonical.com>
 *
 * 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 <fnmatch.h>

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

#include "main.h"
#include "filters.h"

struct filter_node {
	struct filter_node *next;
	char *pattern;
	bool include;
};

static struct filter_node *filter_head = NULL;
static struct filter_node **filter_tail = &filter_head;

void
filter_add(const char *pattern, bool include)
{
	struct filter_node *filter;

	debug(dbg_general, "adding %s filter for '%s'",
	      include ? "include" : "exclude", pattern);

	filter = m_malloc(sizeof(*filter));
	filter->pattern = m_strdup(pattern);
	filter->include = include;
	filter->next = NULL;

	*filter_tail = filter;
	filter_tail = &filter->next;
}

bool
filter_should_skip(struct tar_entry *ti)
{
	struct filter_node *f;
	bool skip = false;

	if (!filter_head)
		return false;

	/* Last match wins. */
	for (f = filter_head; f != NULL; f = f->next) {
		debug(dbg_eachfile, "filter comparing '%s' and '%s'",
		      &ti->name[1], f->pattern);

		if (fnmatch(f->pattern, &ti->name[1], 0) == 0) {
			if (f->include) {
				skip = false;
				debug(dbg_eachfile, "filter including %s",
				      ti->name);
			} else {
				skip = true;
				debug(dbg_eachfile, "filter removing %s",
				      ti->name);
			}
		}
	}

	/* We need to keep directories (or symlinks to directories) if a
	 * glob excludes them, but a more specific include glob brings back
	 * files; XXX the current implementation will probably include more
	 * directories than necessary, but better err on the side of caution
	 * than failing with “no such file or directory” (which would leave
	 * the package in a very bad state). */
	if (skip && (ti->type == TAR_FILETYPE_DIR ||
	             ti->type == TAR_FILETYPE_SYMLINK)) {
		debug(dbg_eachfile,
		      "filter seeing if '%s' needs to be reincluded",
		      &ti->name[1]);

		for (f = filter_head; f != NULL; f = f->next) {
			const char *wildcard;
			int path_len;

			if (!f->include)
				continue;

			/* Calculate the offset of the first wildcard
			 * character in the pattern. */
			wildcard = strpbrk(f->pattern, "*?[\\");
			if (wildcard)
				path_len = wildcard - f->pattern;
			else
				path_len = strlen(f->pattern);

			/* Ignore any trailing slash for the comparison. */
			while (path_len && f->pattern[path_len - 1] == '/')
				path_len--;

			debug(dbg_eachfiledetail,
			      "filter subpattern '%.*s'", path_len, f->pattern);

			if (strncmp(&ti->name[1], f->pattern, path_len) == 0) {
				debug(dbg_eachfile, "filter reincluding %s",
				      ti->name);
				return false;
			}
		}
	}

	return skip;
}