1 /*
2 * inode_io.c --- This is allows an inode in an ext2 filesystem image
3 * to be accessed via the I/O manager interface.
4 *
5 * Copyright (C) 2002 Theodore Ts'o.
6 *
7 * %Begin-Header%
8 * This file may be redistributed under the terms of the GNU Library
9 * General Public License, version 2.
10 * %End-Header%
11 */
12
13 #include "config.h"
14 #include <stdio.h>
15 #include <string.h>
16 #if HAVE_UNISTD_H
17 #include <unistd.h>
18 #endif
19 #if HAVE_ERRNO_H
20 #include <errno.h>
21 #endif
22 #include <time.h>
23
24 #include "ext2_fs.h"
25 #include "ext2fs.h"
26
27 /*
28 * For checking structure magic numbers...
29 */
30
31 #define EXT2_CHECK_MAGIC(struct, code) \
32 if ((struct)->magic != (code)) return (code)
33
34 struct inode_private_data {
35 int magic;
36 char name[32];
37 ext2_file_t file;
38 ext2_filsys fs;
39 ext2_ino_t ino;
40 struct ext2_inode inode;
41 int flags;
42 struct inode_private_data *next;
43 };
44
45 #define CHANNEL_HAS_INODE 0x8000
46
47 static struct inode_private_data *top_intern;
48 static int ino_unique = 0;
49
50 static errcode_t inode_open(const char *name, int flags, io_channel *channel);
51 static errcode_t inode_close(io_channel channel);
52 static errcode_t inode_set_blksize(io_channel channel, int blksize);
53 static errcode_t inode_read_blk(io_channel channel, unsigned long block,
54 int count, void *data);
55 static errcode_t inode_write_blk(io_channel channel, unsigned long block,
56 int count, const void *data);
57 static errcode_t inode_flush(io_channel channel);
58 static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
59 int size, const void *data);
60 static errcode_t inode_read_blk64(io_channel channel,
61 unsigned long long block, int count, void *data);
62 static errcode_t inode_write_blk64(io_channel channel,
63 unsigned long long block, int count, const void *data);
64
65 static struct struct_io_manager struct_inode_manager = {
66 .magic = EXT2_ET_MAGIC_IO_MANAGER,
67 .name = "Inode I/O Manager",
68 .open = inode_open,
69 .close = inode_close,
70 .set_blksize = inode_set_blksize,
71 .read_blk = inode_read_blk,
72 .write_blk = inode_write_blk,
73 .flush = inode_flush,
74 .write_byte = inode_write_byte,
75 .read_blk64 = inode_read_blk64,
76 .write_blk64 = inode_write_blk64
77 };
78
79 io_manager inode_io_manager = &struct_inode_manager;
80
ext2fs_inode_io_intern2(ext2_filsys fs,ext2_ino_t ino,struct ext2_inode * inode,char ** name)81 errcode_t ext2fs_inode_io_intern2(ext2_filsys fs, ext2_ino_t ino,
82 struct ext2_inode *inode,
83 char **name)
84 {
85 struct inode_private_data *data;
86 errcode_t retval;
87
88 if ((retval = ext2fs_get_mem(sizeof(struct inode_private_data),
89 &data)))
90 return retval;
91 data->magic = EXT2_ET_MAGIC_INODE_IO_CHANNEL;
92 sprintf(data->name, "%u:%d", ino, ino_unique++);
93 data->file = 0;
94 data->fs = fs;
95 data->ino = ino;
96 data->flags = 0;
97 if (inode) {
98 memcpy(&data->inode, inode, sizeof(struct ext2_inode));
99 data->flags |= CHANNEL_HAS_INODE;
100 }
101 data->next = top_intern;
102 top_intern = data;
103 *name = data->name;
104 return 0;
105 }
106
ext2fs_inode_io_intern(ext2_filsys fs,ext2_ino_t ino,char ** name)107 errcode_t ext2fs_inode_io_intern(ext2_filsys fs, ext2_ino_t ino,
108 char **name)
109 {
110 return ext2fs_inode_io_intern2(fs, ino, NULL, name);
111 }
112
113
inode_open(const char * name,int flags,io_channel * channel)114 static errcode_t inode_open(const char *name, int flags, io_channel *channel)
115 {
116 io_channel io = NULL;
117 struct inode_private_data *prev, *data = NULL;
118 errcode_t retval;
119 int open_flags;
120
121 if (name == 0)
122 return EXT2_ET_BAD_DEVICE_NAME;
123
124 for (data = top_intern, prev = NULL; data;
125 prev = data, data = data->next)
126 if (strcmp(name, data->name) == 0)
127 break;
128 if (!data)
129 return ENOENT;
130 if (prev)
131 prev->next = data->next;
132 else
133 top_intern = data->next;
134
135 retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);
136 if (retval)
137 goto cleanup;
138 memset(io, 0, sizeof(struct struct_io_channel));
139
140 io->magic = EXT2_ET_MAGIC_IO_CHANNEL;
141 io->manager = inode_io_manager;
142 retval = ext2fs_get_mem(strlen(name)+1, &io->name);
143 if (retval)
144 goto cleanup;
145
146 strcpy(io->name, name);
147 io->private_data = data;
148 io->block_size = 1024;
149 io->read_error = 0;
150 io->write_error = 0;
151 io->refcount = 1;
152
153 open_flags = (flags & IO_FLAG_RW) ? EXT2_FILE_WRITE : 0;
154 retval = ext2fs_file_open2(data->fs, data->ino,
155 (data->flags & CHANNEL_HAS_INODE) ?
156 &data->inode : 0, open_flags,
157 &data->file);
158 if (retval)
159 goto cleanup;
160
161 *channel = io;
162 return 0;
163
164 cleanup:
165 if (io && io->name)
166 ext2fs_free_mem(&io->name);
167 if (data)
168 ext2fs_free_mem(&data);
169 if (io)
170 ext2fs_free_mem(&io);
171 return retval;
172 }
173
inode_close(io_channel channel)174 static errcode_t inode_close(io_channel channel)
175 {
176 struct inode_private_data *data;
177 errcode_t retval = 0;
178
179 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
180 data = (struct inode_private_data *) channel->private_data;
181 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
182
183 if (--channel->refcount > 0)
184 return 0;
185
186 retval = ext2fs_file_close(data->file);
187
188 ext2fs_free_mem(&channel->private_data);
189 if (channel->name)
190 ext2fs_free_mem(&channel->name);
191 ext2fs_free_mem(&channel);
192 return retval;
193 }
194
inode_set_blksize(io_channel channel,int blksize)195 static errcode_t inode_set_blksize(io_channel channel, int blksize)
196 {
197 struct inode_private_data *data;
198
199 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
200 data = (struct inode_private_data *) channel->private_data;
201 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
202
203 channel->block_size = blksize;
204 return 0;
205 }
206
207
inode_read_blk64(io_channel channel,unsigned long long block,int count,void * buf)208 static errcode_t inode_read_blk64(io_channel channel,
209 unsigned long long block, int count, void *buf)
210 {
211 struct inode_private_data *data;
212 errcode_t retval;
213
214 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
215 data = (struct inode_private_data *) channel->private_data;
216 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
217
218 if ((retval = ext2fs_file_lseek(data->file,
219 block * channel->block_size,
220 EXT2_SEEK_SET, 0)))
221 return retval;
222
223 count = (count < 0) ? -count : (count * channel->block_size);
224
225 return ext2fs_file_read(data->file, buf, count, 0);
226 }
227
inode_read_blk(io_channel channel,unsigned long block,int count,void * buf)228 static errcode_t inode_read_blk(io_channel channel, unsigned long block,
229 int count, void *buf)
230 {
231 return inode_read_blk64(channel, block, count, buf);
232 }
233
inode_write_blk64(io_channel channel,unsigned long long block,int count,const void * buf)234 static errcode_t inode_write_blk64(io_channel channel,
235 unsigned long long block, int count, const void *buf)
236 {
237 struct inode_private_data *data;
238 errcode_t retval;
239
240 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
241 data = (struct inode_private_data *) channel->private_data;
242 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
243
244 if ((retval = ext2fs_file_lseek(data->file,
245 block * channel->block_size,
246 EXT2_SEEK_SET, 0)))
247 return retval;
248
249 count = (count < 0) ? -count : (count * channel->block_size);
250
251 return ext2fs_file_write(data->file, buf, count, 0);
252 }
253
inode_write_blk(io_channel channel,unsigned long block,int count,const void * buf)254 static errcode_t inode_write_blk(io_channel channel, unsigned long block,
255 int count, const void *buf)
256 {
257 return inode_write_blk64(channel, block, count, buf);
258 }
259
inode_write_byte(io_channel channel,unsigned long offset,int size,const void * buf)260 static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
261 int size, const void *buf)
262 {
263 struct inode_private_data *data;
264 errcode_t retval = 0;
265
266 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
267 data = (struct inode_private_data *) channel->private_data;
268 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
269
270 if ((retval = ext2fs_file_lseek(data->file, offset,
271 EXT2_SEEK_SET, 0)))
272 return retval;
273
274 return ext2fs_file_write(data->file, buf, size, 0);
275 }
276
277 /*
278 * Flush data buffers to disk.
279 */
inode_flush(io_channel channel)280 static errcode_t inode_flush(io_channel channel)
281 {
282 struct inode_private_data *data;
283
284 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
285 data = (struct inode_private_data *) channel->private_data;
286 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
287
288 return ext2fs_file_flush(data->file);
289 }
290
291