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 "config.h"
13#include <stdio.h>
14#include <stdlib.h>
15#include <string.h>
16#include <strings.h>
17#include <ctype.h>
18#include <errno.h>
19
20#include "e2p.h"
21
22struct mntopt {
23	unsigned int	mask;
24	const char	*string;
25};
26
27static struct mntopt mntopt_list[] = {
28	{ EXT2_DEFM_DEBUG,	"debug" },
29	{ EXT2_DEFM_BSDGROUPS,	"bsdgroups" },
30	{ EXT2_DEFM_XATTR_USER,	"user_xattr" },
31	{ EXT2_DEFM_ACL,	"acl" },
32	{ EXT2_DEFM_UID16,	"uid16" },
33	{ EXT3_DEFM_JMODE_DATA, "journal_data" },
34	{ EXT3_DEFM_JMODE_ORDERED, "journal_data_ordered" },
35	{ EXT3_DEFM_JMODE_WBACK, "journal_data_writeback" },
36	{ EXT4_DEFM_NOBARRIER,	"nobarrier" },
37	{ EXT4_DEFM_BLOCK_VALIDITY, "block_validity" },
38	{ EXT4_DEFM_DISCARD,	"discard"},
39	{ EXT4_DEFM_NODELALLOC,	"nodelalloc"},
40	{ 0, 0 },
41};
42
43const char *e2p_mntopt2string(unsigned int mask)
44{
45	struct mntopt  *f;
46	static char buf[20];
47	int	fnum;
48
49	for (f = mntopt_list; f->string; f++) {
50		if (mask == f->mask)
51			return f->string;
52	}
53	for (fnum = 0; mask >>= 1; fnum++);
54	sprintf(buf, "MNTOPT_%d", fnum);
55	return buf;
56}
57
58int e2p_string2mntopt(char *string, unsigned int *mask)
59{
60	struct mntopt  *f;
61	char		*eptr;
62	int		num;
63
64	for (f = mntopt_list; f->string; f++) {
65		if (!strcasecmp(string, f->string)) {
66			*mask = f->mask;
67			return 0;
68		}
69	}
70	if (strncasecmp(string, "MNTOPT_", 7))
71		return 1;
72
73	if (string[8] == 0)
74		return 1;
75	num = strtol(string+8, &eptr, 10);
76	if (num > 31 || num < 0)
77		return 1;
78	if (*eptr)
79		return 1;
80	*mask = 1 << num;
81	return 0;
82}
83
84static char *skip_over_blanks(char *cp)
85{
86	while (*cp && isspace(*cp))
87		cp++;
88	return cp;
89}
90
91static char *skip_over_word(char *cp)
92{
93	while (*cp && !isspace(*cp) && *cp != ',')
94		cp++;
95	return cp;
96}
97
98/*
99 * Edit a mntopt set array as requested by the user.  The ok
100 * parameter, if non-zero, allows the application to limit what
101 * mntopts the user is allowed to set or clear using this function.
102 */
103int e2p_edit_mntopts(const char *str, __u32 *mntopts, __u32 ok)
104{
105	char	*cp, *buf, *next;
106	int	neg;
107	unsigned int	mask;
108	int	rc = 0;
109
110	buf = malloc(strlen(str)+1);
111	if (!buf)
112		return 1;
113	strcpy(buf, str);
114	cp = buf;
115	while (cp && *cp) {
116		neg = 0;
117		cp = skip_over_blanks(cp);
118		next = skip_over_word(cp);
119		if (*next == 0)
120			next = 0;
121		else
122			*next = 0;
123		switch (*cp) {
124		case '-':
125		case '^':
126			neg++;
127			/* fallthrough */
128		case '+':
129			cp++;
130			break;
131		}
132		if (e2p_string2mntopt(cp, &mask)) {
133			rc = 1;
134			break;
135		}
136		if (ok && !(ok & mask)) {
137			rc = 1;
138			break;
139		}
140		if (mask & EXT3_DEFM_JMODE)
141			*mntopts &= ~EXT3_DEFM_JMODE;
142		if (neg)
143			*mntopts &= ~mask;
144		else
145			*mntopts |= mask;
146		cp = next ? next+1 : 0;
147	}
148	free(buf);
149	return rc;
150}
151