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30#include <linux/fs.h>
31#include <linux/vfs.h>
32#include <linux/slab.h>
33
34#include "squashfs_fs.h"
35#include "squashfs_fs_sb.h"
36#include "squashfs_fs_i.h"
37#include "squashfs.h"
38
39static const unsigned char squashfs_filetype_table[] = {
40 DT_UNKNOWN, DT_DIR, DT_REG, DT_LNK, DT_BLK, DT_CHR, DT_FIFO, DT_SOCK
41};
42
43
44
45
46
47
48
49
50
51static int get_dir_index_using_offset(struct super_block *sb,
52 u64 *next_block, int *next_offset, u64 index_start, int index_offset,
53 int i_count, u64 f_pos)
54{
55 struct squashfs_sb_info *msblk = sb->s_fs_info;
56 int err, i, index, length = 0;
57 unsigned int size;
58 struct squashfs_dir_index dir_index;
59
60 TRACE("Entered get_dir_index_using_offset, i_count %d, f_pos %lld\n",
61 i_count, f_pos);
62
63
64
65
66
67
68 if (f_pos <= 3)
69 return f_pos;
70 f_pos -= 3;
71
72 for (i = 0; i < i_count; i++) {
73 err = squashfs_read_metadata(sb, &dir_index, &index_start,
74 &index_offset, sizeof(dir_index));
75 if (err < 0)
76 break;
77
78 index = le32_to_cpu(dir_index.index);
79 if (index > f_pos)
80
81
82
83 break;
84
85 size = le32_to_cpu(dir_index.size) + 1;
86
87
88 if (size > SQUASHFS_NAME_LEN)
89 break;
90
91 err = squashfs_read_metadata(sb, NULL, &index_start,
92 &index_offset, size);
93 if (err < 0)
94 break;
95
96 length = index;
97 *next_block = le32_to_cpu(dir_index.start_block) +
98 msblk->directory_table;
99 }
100
101 *next_offset = (length + *next_offset) % SQUASHFS_METADATA_SIZE;
102
103
104
105
106 return length + 3;
107}
108
109
110static int squashfs_readdir(struct file *file, struct dir_context *ctx)
111{
112 struct inode *inode = file_inode(file);
113 struct squashfs_sb_info *msblk = inode->i_sb->s_fs_info;
114 u64 block = squashfs_i(inode)->start + msblk->directory_table;
115 int offset = squashfs_i(inode)->offset, length, err;
116 unsigned int inode_number, dir_count, size, type;
117 struct squashfs_dir_header dirh;
118 struct squashfs_dir_entry *dire;
119
120 TRACE("Entered squashfs_readdir [%llx:%x]\n", block, offset);
121
122 dire = kmalloc(sizeof(*dire) + SQUASHFS_NAME_LEN + 1, GFP_KERNEL);
123 if (dire == NULL) {
124 ERROR("Failed to allocate squashfs_dir_entry\n");
125 goto finish;
126 }
127
128
129
130
131
132
133
134
135
136 while (ctx->pos < 3) {
137 char *name;
138 int i_ino;
139
140 if (ctx->pos == 0) {
141 name = ".";
142 size = 1;
143 i_ino = inode->i_ino;
144 } else {
145 name = "..";
146 size = 2;
147 i_ino = squashfs_i(inode)->parent;
148 }
149
150 if (!dir_emit(ctx, name, size, i_ino,
151 squashfs_filetype_table[1]))
152 goto finish;
153
154 ctx->pos += size;
155 }
156
157 length = get_dir_index_using_offset(inode->i_sb, &block, &offset,
158 squashfs_i(inode)->dir_idx_start,
159 squashfs_i(inode)->dir_idx_offset,
160 squashfs_i(inode)->dir_idx_cnt,
161 ctx->pos);
162
163 while (length < i_size_read(inode)) {
164
165
166
167 err = squashfs_read_metadata(inode->i_sb, &dirh, &block,
168 &offset, sizeof(dirh));
169 if (err < 0)
170 goto failed_read;
171
172 length += sizeof(dirh);
173
174 dir_count = le32_to_cpu(dirh.count) + 1;
175
176 if (dir_count > SQUASHFS_DIR_COUNT)
177 goto failed_read;
178
179 while (dir_count--) {
180
181
182
183 err = squashfs_read_metadata(inode->i_sb, dire, &block,
184 &offset, sizeof(*dire));
185 if (err < 0)
186 goto failed_read;
187
188 size = le16_to_cpu(dire->size) + 1;
189
190
191 if (size > SQUASHFS_NAME_LEN)
192 goto failed_read;
193
194 err = squashfs_read_metadata(inode->i_sb, dire->name,
195 &block, &offset, size);
196 if (err < 0)
197 goto failed_read;
198
199 length += sizeof(*dire) + size;
200
201 if (ctx->pos >= length)
202 continue;
203
204 dire->name[size] = '\0';
205 inode_number = le32_to_cpu(dirh.inode_number) +
206 ((short) le16_to_cpu(dire->inode_number));
207 type = le16_to_cpu(dire->type);
208
209 if (type > SQUASHFS_MAX_DIR_TYPE)
210 goto failed_read;
211
212 if (!dir_emit(ctx, dire->name, size,
213 inode_number,
214 squashfs_filetype_table[type]))
215 goto finish;
216
217 ctx->pos = length;
218 }
219 }
220
221finish:
222 kfree(dire);
223 return 0;
224
225failed_read:
226 ERROR("Unable to read directory block [%llx:%x]\n", block, offset);
227 kfree(dire);
228 return 0;
229}
230
231
232const struct file_operations squashfs_dir_ops = {
233 .read = generic_read_dir,
234 .iterate_shared = squashfs_readdir,
235 .llseek = generic_file_llseek,
236};
237