1 /* SPDX-License-Identifier: GPL-2.0 */
2 #include <linux/fs.h>
3 #include <linux/buffer_head.h>
4 #include <linux/exportfs.h>
5 #include <linux/iso_fs.h>
6 #include <linux/unaligned.h>
7 
8 enum isofs_file_format {
9 	isofs_file_normal = 0,
10 	isofs_file_sparse = 1,
11 	isofs_file_compressed = 2,
12 };
13 
14 /*
15  * iso fs inode data in memory
16  */
17 struct iso_inode_info {
18 	unsigned long i_iget5_block;
19 	unsigned long i_iget5_offset;
20 	unsigned int i_first_extent;
21 	unsigned char i_file_format;
22 	unsigned char i_format_parm[3];
23 	unsigned long i_next_section_block;
24 	unsigned long i_next_section_offset;
25 	off_t i_section_size;
26 	struct inode vfs_inode;
27 };
28 
29 /*
30  * iso9660 super-block data in memory
31  */
32 struct isofs_sb_info {
33 	unsigned long s_ninodes;
34 	unsigned long s_nzones;
35 	unsigned long s_firstdatazone;
36 	unsigned long s_log_zone_size;
37 	unsigned long s_max_size;
38 
39 	int           s_rock_offset; /* offset of SUSP fields within SU area */
40 	s32           s_sbsector;
41 	unsigned char s_joliet_level;
42 	unsigned char s_mapping;
43 	unsigned char s_check;
44 	unsigned char s_session;
45 	unsigned int  s_high_sierra:1;
46 	unsigned int  s_rock:2;
47 	unsigned int  s_cruft:1; /* Broken disks with high byte of length
48 				  * containing junk */
49 	unsigned int  s_nocompress:1;
50 	unsigned int  s_hide:1;
51 	unsigned int  s_showassoc:1;
52 	unsigned int  s_overriderockperm:1;
53 	unsigned int  s_uid_set:1;
54 	unsigned int  s_gid_set:1;
55 
56 	umode_t s_fmode;
57 	umode_t s_dmode;
58 	kgid_t s_gid;
59 	kuid_t s_uid;
60 	struct nls_table *s_nls_iocharset; /* Native language support table */
61 };
62 
63 #define ISOFS_INVALID_MODE ((umode_t) -1)
64 
65 static inline struct isofs_sb_info *ISOFS_SB(struct super_block *sb)
66 {
67 	return sb->s_fs_info;
68 }
69 
70 static inline struct iso_inode_info *ISOFS_I(struct inode *inode)
71 {
72 	return container_of(inode, struct iso_inode_info, vfs_inode);
73 }
74 
75 static inline int isonum_711(u8 *p)
76 {
77 	return *p;
78 }
79 static inline int isonum_712(s8 *p)
80 {
81 	return *p;
82 }
83 static inline unsigned int isonum_721(u8 *p)
84 {
85 	return get_unaligned_le16(p);
86 }
87 static inline unsigned int isonum_722(u8 *p)
88 {
89 	return get_unaligned_be16(p);
90 }
91 static inline unsigned int isonum_723(u8 *p)
92 {
93 	/* Ignore bigendian datum due to broken mastering programs */
94 	return get_unaligned_le16(p);
95 }
96 static inline unsigned int isonum_731(u8 *p)
97 {
98 	return get_unaligned_le32(p);
99 }
100 static inline unsigned int isonum_732(u8 *p)
101 {
102 	return get_unaligned_be32(p);
103 }
104 static inline unsigned int isonum_733(u8 *p)
105 {
106 	/* Ignore bigendian datum due to broken mastering programs */
107 	return get_unaligned_le32(p);
108 }
109 #define ISO_DATE_HIGH_SIERRA (1 << 0)
110 #define ISO_DATE_LONG_FORM (1 << 1)
111 struct timespec64 iso_date(u8 *p, int flags);
112 
113 struct inode;		/* To make gcc happy */
114 
115 extern int parse_rock_ridge_inode(struct iso_directory_record *, struct inode *, int relocated);
116 extern int get_rock_ridge_filename(struct iso_directory_record *, char *, struct inode *);
117 extern int isofs_name_translate(struct iso_directory_record *, char *, struct inode *);
118 
119 int get_joliet_filename(struct iso_directory_record *, unsigned char *, struct inode *);
120 int get_acorn_filename(struct iso_directory_record *, char *, struct inode *);
121 
122 extern struct dentry *isofs_lookup(struct inode *, struct dentry *, unsigned int flags);
123 extern struct buffer_head *isofs_bread(struct inode *, sector_t);
124 extern int isofs_get_blocks(struct inode *, sector_t, struct buffer_head **, unsigned long);
125 
126 struct inode *__isofs_iget(struct super_block *sb,
127 			   unsigned long block,
128 			   unsigned long offset,
129 			   int relocated);
130 
131 static inline struct inode *isofs_iget(struct super_block *sb,
132 				       unsigned long block,
133 				       unsigned long offset)
134 {
135 	return __isofs_iget(sb, block, offset, 0);
136 }
137 
138 static inline struct inode *isofs_iget_reloc(struct super_block *sb,
139 					     unsigned long block,
140 					     unsigned long offset)
141 {
142 	return __isofs_iget(sb, block, offset, 1);
143 }
144 
145 /* Because the inode number is no longer relevant to finding the
146  * underlying meta-data for an inode, we are free to choose a more
147  * convenient 32-bit number as the inode number.  The inode numbering
148  * scheme was recommended by Sergey Vlasov and Eric Lammerts. */
149 static inline unsigned long isofs_get_ino(unsigned long block,
150 					  unsigned long offset,
151 					  unsigned long bufbits)
152 {
153 	return (block << (bufbits - 5)) | (offset >> 5);
154 }
155 
156 /* Every directory can have many redundant directory entries scattered
157  * throughout the directory tree.  First there is the directory entry
158  * with the name of the directory stored in the parent directory.
159  * Then, there is the "." directory entry stored in the directory
160  * itself.  Finally, there are possibly many ".." directory entries
161  * stored in all the subdirectories.
162  *
163  * In order for the NFS get_parent() method to work and for the
164  * general consistency of the dcache, we need to make sure the
165  * "i_iget5_block" and "i_iget5_offset" all point to exactly one of
166  * the many redundant entries for each directory.  We normalize the
167  * block and offset by always making them point to the "."  directory.
168  *
169  * Notice that we do not use the entry for the directory with the name
170  * that is located in the parent directory.  Even though choosing this
171  * first directory is more natural, it is much easier to find the "."
172  * entry in the NFS get_parent() method because it is implicitly
173  * encoded in the "extent + ext_attr_length" fields of _all_ the
174  * redundant entries for the directory.  Thus, it can always be
175  * reached regardless of which directory entry you have in hand.
176  *
177  * This works because the "." entry is simply the first directory
178  * record when you start reading the file that holds all the directory
179  * records, and this file starts at "extent + ext_attr_length" blocks.
180  * Because the "." entry is always the first entry listed in the
181  * directories file, the normalized "offset" value is always 0.
182  *
183  * You should pass the directory entry in "de".  On return, "block"
184  * and "offset" will hold normalized values.  Only directories are
185  * affected making it safe to call even for non-directory file
186  * types. */
187 static inline void
188 isofs_normalize_block_and_offset(struct iso_directory_record* de,
189 				 unsigned long *block,
190 				 unsigned long *offset)
191 {
192 	/* Only directories are normalized. */
193 	if (de->flags[0] & 2) {
194 		*offset = 0;
195 		*block = (unsigned long)isonum_733(de->extent)
196 			+ (unsigned long)isonum_711(de->ext_attr_length);
197 	}
198 }
199 
200 extern const struct inode_operations isofs_dir_inode_operations;
201 extern const struct file_operations isofs_dir_operations;
202 extern const struct address_space_operations isofs_symlink_aops;
203 extern const struct export_operations isofs_export_ops;
204