feature.c revision 39dc1c45cb41ce37a56d364103bb852d0b62c835 
1/*
2 * feature.c --- convert between features and strings
3 *
4 * Copyright (C) 1999  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 feature {
20	int		compat;
21	unsigned int	mask;
22	const char	*string;
23};
24
25static struct feature feature_list[] = {
26	{	E2P_FEATURE_COMPAT, EXT2_FEATURE_COMPAT_DIR_PREALLOC,
27			"dir_prealloc" },
28	{	E2P_FEATURE_COMPAT, EXT3_FEATURE_COMPAT_HAS_JOURNAL,
29			"has_journal" },
30	{	E2P_FEATURE_COMPAT, EXT2_FEATURE_COMPAT_IMAGIC_INODES,
31			"imagic_inodes" },
32	{	E2P_FEATURE_COMPAT, EXT2_FEATURE_COMPAT_EXT_ATTR,
33			"ext_attr" },
34	{	E2P_FEATURE_COMPAT, EXT2_FEATURE_COMPAT_DIR_INDEX,
35			"dir_index" },
36	{	E2P_FEATURE_COMPAT, EXT2_FEATURE_COMPAT_RESIZE_INODE,
37			"resize_inode" },
38	{	E2P_FEATURE_RO_INCOMPAT, EXT2_FEATURE_RO_COMPAT_SPARSE_SUPER,
39			"sparse_super" },
40	{	E2P_FEATURE_RO_INCOMPAT, EXT2_FEATURE_RO_COMPAT_LARGE_FILE,
41			"large_file" },
42	{	E2P_FEATURE_INCOMPAT, EXT2_FEATURE_INCOMPAT_COMPRESSION,
43			"compression" },
44	{	E2P_FEATURE_INCOMPAT, EXT2_FEATURE_INCOMPAT_FILETYPE,
45			"filetype" },
46	{	E2P_FEATURE_INCOMPAT, EXT3_FEATURE_INCOMPAT_RECOVER,
47			"needs_recovery" },
48	{	E2P_FEATURE_INCOMPAT, EXT3_FEATURE_INCOMPAT_JOURNAL_DEV,
49			"journal_dev" },
50	{	E2P_FEATURE_INCOMPAT, EXT3_FEATURE_INCOMPAT_EXTENTS,
51			"extents" },
52	{	E2P_FEATURE_INCOMPAT, EXT2_FEATURE_INCOMPAT_META_BG,
53			"meta_bg" },
54	{	0, 0, 0 },
55};
56
57const char *e2p_feature2string(int compat, unsigned int mask)
58{
59	struct feature  *f;
60	static char buf[20];
61	char	fchar;
62	int	fnum;
63
64	for (f = feature_list; f->string; f++) {
65		if ((compat == f->compat) &&
66		    (mask == f->mask))
67			return f->string;
68	}
69	switch (compat) {
70	case  E2P_FEATURE_COMPAT:
71		fchar = 'C';
72		break;
73	case E2P_FEATURE_INCOMPAT:
74		fchar = 'I';
75		break;
76	case E2P_FEATURE_RO_INCOMPAT:
77		fchar = 'R';
78		break;
79	default:
80		fchar = '?';
81		break;
82	}
83	for (fnum = 0; mask >>= 1; fnum++);
84	sprintf(buf, "FEATURE_%c%d", fchar, fnum);
85	return buf;
86}
87
88int e2p_string2feature(char *string, int *compat_type, unsigned int *mask)
89{
90	struct feature  *f;
91	char		*eptr;
92	int		num;
93
94	for (f = feature_list; f->string; f++) {
95		if (!strcasecmp(string, f->string)) {
96			*compat_type = f->compat;
97			*mask = f->mask;
98			return 0;
99		}
100	}
101	if (strncasecmp(string, "FEATURE_", 8))
102		return 1;
103
104	switch (string[8]) {
105	case 'c':
106	case 'C':
107		*compat_type = E2P_FEATURE_COMPAT;
108		break;
109	case 'i':
110	case 'I':
111		*compat_type = E2P_FEATURE_INCOMPAT;
112		break;
113	case 'r':
114	case 'R':
115		*compat_type = E2P_FEATURE_RO_INCOMPAT;
116		break;
117	default:
118		return 1;
119	}
120	if (string[9] == 0)
121		return 1;
122	num = strtol(string+9, &eptr, 10);
123	if (num > 32 || num < 0)
124		return 1;
125	if (*eptr)
126		return 1;
127	*mask = 1 << num;
128	return 0;
129}
130
131static char *skip_over_blanks(char *cp)
132{
133	while (*cp && isspace(*cp))
134		cp++;
135	return cp;
136}
137
138static char *skip_over_word(char *cp)
139{
140	while (*cp && !isspace(*cp) && *cp != ',')
141		cp++;
142	return cp;
143}
144
145/*
146 * Edit a feature set array as requested by the user.  The ok_array,
147 * if set, allows the application to limit what features the user is
148 * allowed to set or clear using this function.
149 */
150int e2p_edit_feature(const char *str, __u32 *compat_array, __u32 *ok_array)
151{
152	char	*cp, *buf, *next;
153	int	neg;
154	unsigned int	mask;
155	int		compat_type;
156
157	buf = malloc(strlen(str)+1);
158	if (!buf)
159		return 1;
160	strcpy(buf, str);
161	cp = buf;
162	while (cp && *cp) {
163		neg = 0;
164		cp = skip_over_blanks(cp);
165		next = skip_over_word(cp);
166		if (*next == 0)
167			next = 0;
168		else
169			*next = 0;
170		switch (*cp) {
171		case '-':
172		case '^':
173			neg++;
174		case '+':
175			cp++;
176			break;
177		}
178		if (e2p_string2feature(cp, &compat_type, &mask))
179			return 1;
180		if (ok_array && !(ok_array[compat_type] & mask))
181			return 1;
182		if (neg)
183			compat_array[compat_type] &= ~mask;
184		else
185			compat_array[compat_type] |= mask;
186		cp = next ? next+1 : 0;
187	}
188	return 0;
189}
190
191