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