mntopts.c revision 63165136eab4ef01dae295c8e290c2a3853c936b 
1/*
2 * mountopts.c --- convert between default mount options and strings
3 *
4 * Copyright (C) 2002  Theodore Ts'o <tytso@mit.edu>
5 *
6 * %Begin-Header%
7 * This file may be redistributed under the terms of the GNU Library
8 * General Public License, version 2.
9 * %End-Header%
10 */
11
12#include <stdio.h>
13#include <stdlib.h>
14#include <string.h>
15#include <ctype.h>
16#include <errno.h>
17
18#include "e2p.h"
19
20struct mntopt {
21	unsigned int	mask;
22	const char	*string;
23};
24
25static struct mntopt mntopt_list[] = {
26	{ EXT2_DEFM_DEBUG,	"debug" },
27	{ EXT2_DEFM_BSDGROUPS,	"bsdgroups" },
28	{ EXT2_DEFM_XATTR_USER,	"user_xattr" },
29	{ EXT2_DEFM_ACL,	"acl" },
30	{ EXT2_DEFM_UID16,	"uid16" },
31	{ EXT3_DEFM_JMODE_DATA, "journal_data" },
32	{ EXT3_DEFM_JMODE_ORDERED, "journal_data_ordered" },
33	{ EXT3_DEFM_JMODE_WBACK, "journal_data_writeback" },
34	{ EXT4_DEFM_NOBARRIER,	"nobarrier" },
35	{ EXT4_DEFM_BLOCK_VALIDITY, "block_validity" },
36	{ EXT4_DEFM_DISCARD,	"discard"},
37	{ EXT4_DEFM_NODELALLOC,	"nodelalloc"},
38	{ 0, 0 },
39};
40
41const char *e2p_mntopt2string(unsigned int mask)
42{
43	struct mntopt  *f;
44	static char buf[20];
45	int	fnum;
46
47	for (f = mntopt_list; f->string; f++) {
48		if (mask == f->mask)
49			return f->string;
50	}
51	for (fnum = 0; mask >>= 1; fnum++);
52	sprintf(buf, "MNTOPT_%d", fnum);
53	return buf;
54}
55
56int e2p_string2mntopt(char *string, unsigned int *mask)
57{
58	struct mntopt  *f;
59	char		*eptr;
60	int		num;
61
62	for (f = mntopt_list; f->string; f++) {
63		if (!strcasecmp(string, f->string)) {
64			*mask = f->mask;
65			return 0;
66		}
67	}
68	if (strncasecmp(string, "MNTOPT_", 7))
69		return 1;
70
71	if (string[8] == 0)
72		return 1;
73	num = strtol(string+8, &eptr, 10);
74	if (num > 32 || num < 0)
75		return 1;
76	if (*eptr)
77		return 1;
78	*mask = 1 << num;
79	return 0;
80}
81
82static char *skip_over_blanks(char *cp)
83{
84	while (*cp && isspace(*cp))
85		cp++;
86	return cp;
87}
88
89static char *skip_over_word(char *cp)
90{
91	while (*cp && !isspace(*cp) && *cp != ',')
92		cp++;
93	return cp;
94}
95
96/*
97 * Edit a mntopt set array as requested by the user.  The ok
98 * parameter, if non-zero, allows the application to limit what
99 * mntopts the user is allowed to set or clear using this function.
100 */
101int e2p_edit_mntopts(const char *str, __u32 *mntopts, __u32 ok)
102{
103	char	*cp, *buf, *next;
104	int	neg;
105	unsigned int	mask;
106	int	rc = 0;
107
108	buf = malloc(strlen(str)+1);
109	if (!buf)
110		return 1;
111	strcpy(buf, str);
112	cp = buf;
113	while (cp && *cp) {
114		neg = 0;
115		cp = skip_over_blanks(cp);
116		next = skip_over_word(cp);
117		if (*next == 0)
118			next = 0;
119		else
120			*next = 0;
121		switch (*cp) {
122		case '-':
123		case '^':
124			neg++;
125		case '+':
126			cp++;
127			break;
128		}
129		if (e2p_string2mntopt(cp, &mask)) {
130			rc = 1;
131			break;
132		}
133		if (ok && !(ok & mask)) {
134			rc = 1;
135			break;
136		}
137		if (mask & EXT3_DEFM_JMODE)
138			*mntopts &= ~EXT3_DEFM_JMODE;
139		if (neg)
140			*mntopts &= ~mask;
141		else
142			*mntopts |= mask;
143		cp = next ? next+1 : 0;
144	}
145	free(buf);
146	return rc;
147}
148