mntopts.c revision efc6f628e15de95bcd13e4f0ee223cb42115d520 
1/*
2 * mountopts.c --- convert between default mount options and strings
3 *
4 * Copyright (C) 2002  Theodore Ts'o <tytso@mit.edu>
5 *
6 * This file can be redistributed under the terms of the GNU Library General
7 * Public License
8 *
9 */
10
11#include <stdio.h>
12#include <stdlib.h>
13#include <string.h>
14#include <ctype.h>
15#include <errno.h>
16
17#include "e2p.h"
18
19struct mntopt {
20	unsigned int	mask;
21	const char	*string;
22};
23
24static struct mntopt mntopt_list[] = {
25	{ EXT2_DEFM_DEBUG,	"debug" },
26	{ EXT2_DEFM_BSDGROUPS,	"bsdgroups" },
27	{ EXT2_DEFM_XATTR_USER,	"user_xattr" },
28	{ EXT2_DEFM_ACL,	"acl" },
29	{ EXT2_DEFM_UID16,	"uid16" },
30	{ EXT3_DEFM_JMODE_DATA, "journal_data" },
31	{ EXT3_DEFM_JMODE_ORDERED, "journal_data_ordered" },
32	{ EXT3_DEFM_JMODE_WBACK, "journal_data_writeback" },
33	{ 0, 0 },
34};
35
36const char *e2p_mntopt2string(unsigned int mask)
37{
38	struct mntopt  *f;
39	static char buf[20];
40	int	fnum;
41
42	for (f = mntopt_list; f->string; f++) {
43		if (mask == f->mask)
44			return f->string;
45	}
46	for (fnum = 0; mask >>= 1; fnum++);
47	sprintf(buf, "MNTOPT_%d", fnum);
48	return buf;
49}
50
51int e2p_string2mntopt(char *string, unsigned int *mask)
52{
53	struct mntopt  *f;
54	char		*eptr;
55	int		num;
56
57	for (f = mntopt_list; f->string; f++) {
58		if (!strcasecmp(string, f->string)) {
59			*mask = f->mask;
60			return 0;
61		}
62	}
63	if (strncasecmp(string, "MNTOPT_", 8))
64		return 1;
65
66	if (string[8] == 0)
67		return 1;
68	num = strtol(string+8, &eptr, 10);
69	if (num > 32 || num < 0)
70		return 1;
71	if (*eptr)
72		return 1;
73	*mask = 1 << num;
74	return 0;
75}
76
77static char *skip_over_blanks(char *cp)
78{
79	while (*cp && isspace(*cp))
80		cp++;
81	return cp;
82}
83
84static char *skip_over_word(char *cp)
85{
86	while (*cp && !isspace(*cp) && *cp != ',')
87		cp++;
88	return cp;
89}
90
91/*
92 * Edit a mntopt set array as requested by the user.  The ok
93 * parameter, if non-zero, allows the application to limit what
94 * mntopts the user is allowed to set or clear using this function.
95 */
96int e2p_edit_mntopts(const char *str, __u32 *mntopts, __u32 ok)
97{
98	char	*cp, *buf, *next;
99	int	neg;
100	unsigned int	mask;
101	int	rc = 0;
102
103	buf = malloc(strlen(str)+1);
104	if (!buf)
105		return 1;
106	strcpy(buf, str);
107	cp = buf;
108	while (cp && *cp) {
109		neg = 0;
110		cp = skip_over_blanks(cp);
111		next = skip_over_word(cp);
112		if (*next == 0)
113			next = 0;
114		else
115			*next = 0;
116		switch (*cp) {
117		case '-':
118		case '^':
119			neg++;
120		case '+':
121			cp++;
122			break;
123		}
124		if (e2p_string2mntopt(cp, &mask)) {
125			rc = 1;
126			break;
127		}
128		if (ok && !(ok & mask)) {
129			rc = 1;
130			break;
131		}
132		if (mask & EXT3_DEFM_JMODE)
133			*mntopts &= ~EXT3_DEFM_JMODE;
134		if (neg)
135			*mntopts &= ~mask;
136		else
137			*mntopts |= mask;
138		cp = next ? next+1 : 0;
139	}
140	free(buf);
141	return rc;
142}
143