summaryrefslogtreecommitdiffstats
path: root/mtab.c
blob: 0311c509063663a4f12736f903fd86da5521ef6a (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
/*********************************************************************
 * bfs                                                               *
 * Copyright (C) 2017 Tavian Barnes <tavianator@tavianator.com>      *
 *                                                                   *
 * This program is free software. It comes without any warranty, to  *
 * the extent permitted by applicable law. You can redistribute it   *
 * and/or modify it under the terms of the Do What The Fuck You Want *
 * To Public License, Version 2, as published by Sam Hocevar. See    *
 * the COPYING file or http://www.wtfpl.net/ for more details.       *
 *********************************************************************/

#include "mtab.h"
#include <errno.h>
#include <stdlib.h>
#include <string.h>
#include <sys/param.h>
#include <sys/stat.h>
#include <sys/types.h>

#if __linux__
#	include <mntent.h>
#elif BSD
#	include <sys/mount.h>
#	include <sys/ucred.h>
#endif

/**
 * A mount point in the mount table.
 */
struct bfs_mtab_entry {
	/** The device number for this mount point. */
	dev_t dev;
	/** The file system type of this mount point. */
	char *type;
};

struct bfs_mtab {
	/** The array of mtab entries. */
	struct bfs_mtab_entry *table;
	/** The size of the array. */
	size_t size;
	/** Capacity of the array. */
	size_t capacity;
};

/**
 * Add an entry to the mount table.
 */
static int bfs_mtab_push(struct bfs_mtab *mtab, dev_t dev, const char *type) {
	size_t size = mtab->size + 1;

	if (size >= mtab->capacity) {
		size_t capacity = 2*size;
		struct bfs_mtab_entry *table = realloc(mtab->table, capacity*sizeof(*table));
		if (!table) {
			return -1;
		}
		mtab->table = table;
		mtab->capacity = capacity;
	}

	struct bfs_mtab_entry *entry = mtab->table + (size - 1);
	entry->dev = dev;
	entry->type = strdup(type);
	if (!entry->type) {
		return -1;
	}

	mtab->size = size;
	return 0;
}

struct bfs_mtab *parse_bfs_mtab() {
#if __linux__

	FILE *file = setmntent("/etc/mtab", "r");
	if (!file) {
		goto fail;
	}

	struct bfs_mtab *mtab = malloc(sizeof(*mtab));
	if (!mtab) {
		goto fail_file;
	}
	mtab->table = NULL;
	mtab->size = 0;
	mtab->capacity = 0;

	struct mntent *mnt;
	while ((mnt = getmntent(file))) {
		struct stat sb;
		if (stat(mnt->mnt_dir, &sb) != 0) {
			continue;
		}

		if (bfs_mtab_push(mtab, sb.st_dev, mnt->mnt_type) != 0) {
			goto fail_mtab;
		}
	}

	endmntent(file);
	return mtab;

fail_mtab:
	free_bfs_mtab(mtab);
fail_file:
	endmntent(file);
fail:
	return NULL;

#elif BSD

	struct statfs *mntbuf;
	int size = getmntinfo(&mntbuf, MNT_WAIT);
	if (size < 0) {
		return NULL;
	}

	struct bfs_mtab *mtab = malloc(sizeof(*mtab));
	if (!mtab) {
		goto fail;
	}

	mtab->size = 0;
	mtab->table = malloc(size*sizeof(*mtab->table));
	if (!mtab->table) {
		goto fail_mtab;
	}
	mtab->capacity = size;

	for (struct statfs *mnt = mntbuf; mnt < mntbuf + size; ++mnt) {
		struct stat sb;
		if (stat(mnt->f_mntonname, &sb) != 0) {
			continue;
		}

		if (bfs_mtab_push(mtab, sb.st_dev, mnt->f_fstypename) != 0) {
			goto fail_mtab;
		}
	}

	return mtab;

fail_mtab:
	free_bfs_mtab(mtab);
fail:
	return NULL;

#else

	errno = ENOTSUP;
	return NULL;
#endif
}

const char *bfs_fstype(const struct bfs_mtab *mtab, const struct stat *statbuf) {
	for (struct bfs_mtab_entry *mnt = mtab->table; mnt < mtab->table + mtab->size; ++mnt) {
		if (statbuf->st_dev == mnt->dev) {
			return mnt->type;
		}
	}

	return "unknown";
}

void free_bfs_mtab(struct bfs_mtab *mtab) {
	if (mtab) {
		for (struct bfs_mtab_entry *mnt = mtab->table; mnt < mtab->table + mtab->size; ++mnt) {
			free(mnt->type);
		}
		free(mtab->table);
		free(mtab);
	}
}