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Diffstat (limited to 'e2fsprogs/ext2fs/inode_io.c')
-rw-r--r--e2fsprogs/ext2fs/inode_io.c270
1 files changed, 270 insertions, 0 deletions
diff --git a/e2fsprogs/ext2fs/inode_io.c b/e2fsprogs/ext2fs/inode_io.c
new file mode 100644
index 000000000..b5c08b90a
--- /dev/null
+++ b/e2fsprogs/ext2fs/inode_io.c
@@ -0,0 +1,270 @@
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 Public
9 * License.
10 * %End-Header%
11 */
12
13#include <stdio.h>
14#include <string.h>
15#if HAVE_UNISTD_H
16#include <unistd.h>
17#endif
18#if HAVE_ERRNO_H
19#include <errno.h>
20#endif
21#include <time.h>
22
23#include "ext2_fs.h"
24#include "ext2fs.h"
25
26/*
27 * For checking structure magic numbers...
28 */
29
30#define EXT2_CHECK_MAGIC(struct, code) \
31 if ((struct)->magic != (code)) return (code)
32
33struct inode_private_data {
34 int magic;
35 char name[32];
36 ext2_file_t file;
37 ext2_filsys fs;
38 ext2_ino_t ino;
39 struct ext2_inode inode;
40 int flags;
41 struct inode_private_data *next;
42};
43
44#define CHANNEL_HAS_INODE 0x8000
45
46static struct inode_private_data *top_intern;
47static int ino_unique = 0;
48
49static errcode_t inode_open(const char *name, int flags, io_channel *channel);
50static errcode_t inode_close(io_channel channel);
51static errcode_t inode_set_blksize(io_channel channel, int blksize);
52static errcode_t inode_read_blk(io_channel channel, unsigned long block,
53 int count, void *data);
54static errcode_t inode_write_blk(io_channel channel, unsigned long block,
55 int count, const void *data);
56static errcode_t inode_flush(io_channel channel);
57static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
58 int size, const void *data);
59
60static struct struct_io_manager struct_inode_manager = {
61 EXT2_ET_MAGIC_IO_MANAGER,
62 "Inode I/O Manager",
63 inode_open,
64 inode_close,
65 inode_set_blksize,
66 inode_read_blk,
67 inode_write_blk,
68 inode_flush,
69 inode_write_byte
70};
71
72io_manager inode_io_manager = &struct_inode_manager;
73
74errcode_t ext2fs_inode_io_intern2(ext2_filsys fs, ext2_ino_t ino,
75 struct ext2_inode *inode,
76 char **name)
77{
78 struct inode_private_data *data;
79 errcode_t retval;
80
81 if ((retval = ext2fs_get_mem(sizeof(struct inode_private_data),
82 &data)))
83 return retval;
84 data->magic = EXT2_ET_MAGIC_INODE_IO_CHANNEL;
85 sprintf(data->name, "%u:%d", ino, ino_unique++);
86 data->file = 0;
87 data->fs = fs;
88 data->ino = ino;
89 data->flags = 0;
90 if (inode) {
91 memcpy(&data->inode, inode, sizeof(struct ext2_inode));
92 data->flags |= CHANNEL_HAS_INODE;
93 }
94 data->next = top_intern;
95 top_intern = data;
96 *name = data->name;
97 return 0;
98}
99
100errcode_t ext2fs_inode_io_intern(ext2_filsys fs, ext2_ino_t ino,
101 char **name)
102{
103 return ext2fs_inode_io_intern2(fs, ino, NULL, name);
104}
105
106
107static errcode_t inode_open(const char *name, int flags, io_channel *channel)
108{
109 io_channel io = NULL;
110 struct inode_private_data *prev, *data = NULL;
111 errcode_t retval;
112 int open_flags;
113
114 if (name == 0)
115 return EXT2_ET_BAD_DEVICE_NAME;
116
117 for (data = top_intern, prev = NULL; data;
118 prev = data, data = data->next)
119 if (strcmp(name, data->name) == 0)
120 break;
121 if (!data)
122 return ENOENT;
123 if (prev)
124 prev->next = data->next;
125 else
126 top_intern = data->next;
127
128 retval = ext2fs_get_mem(sizeof(struct struct_io_channel), &io);
129 if (retval)
130 goto cleanup;
131 memset(io, 0, sizeof(struct struct_io_channel));
132
133 io->magic = EXT2_ET_MAGIC_IO_CHANNEL;
134 io->manager = inode_io_manager;
135 retval = ext2fs_get_mem(strlen(name)+1, &io->name);
136 if (retval)
137 goto cleanup;
138
139 strcpy(io->name, name);
140 io->private_data = data;
141 io->block_size = 1024;
142 io->read_error = 0;
143 io->write_error = 0;
144 io->refcount = 1;
145
146 open_flags = (flags & IO_FLAG_RW) ? EXT2_FILE_WRITE : 0;
147 retval = ext2fs_file_open2(data->fs, data->ino,
148 (data->flags & CHANNEL_HAS_INODE) ?
149 &data->inode : 0, open_flags,
150 &data->file);
151 if (retval)
152 goto cleanup;
153
154 *channel = io;
155 return 0;
156
157cleanup:
158 if (data) {
159 ext2fs_free_mem(&data);
160 }
161 if (io)
162 ext2fs_free_mem(&io);
163 return retval;
164}
165
166static errcode_t inode_close(io_channel channel)
167{
168 struct inode_private_data *data;
169 errcode_t retval = 0;
170
171 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
172 data = (struct inode_private_data *) channel->private_data;
173 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
174
175 if (--channel->refcount > 0)
176 return 0;
177
178 retval = ext2fs_file_close(data->file);
179
180 ext2fs_free_mem(&channel->private_data);
181 if (channel->name)
182 ext2fs_free_mem(&channel->name);
183 ext2fs_free_mem(&channel);
184 return retval;
185}
186
187static errcode_t inode_set_blksize(io_channel channel, int blksize)
188{
189 struct inode_private_data *data;
190
191 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
192 data = (struct inode_private_data *) channel->private_data;
193 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
194
195 channel->block_size = blksize;
196 return 0;
197}
198
199
200static errcode_t inode_read_blk(io_channel channel, unsigned long block,
201 int count, void *buf)
202{
203 struct inode_private_data *data;
204 errcode_t retval;
205
206 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
207 data = (struct inode_private_data *) channel->private_data;
208 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
209
210 if ((retval = ext2fs_file_lseek(data->file,
211 block * channel->block_size,
212 EXT2_SEEK_SET, 0)))
213 return retval;
214
215 count = (count < 0) ? -count : (count * channel->block_size);
216
217 return ext2fs_file_read(data->file, buf, count, 0);
218}
219
220static errcode_t inode_write_blk(io_channel channel, unsigned long block,
221 int count, const void *buf)
222{
223 struct inode_private_data *data;
224 errcode_t retval;
225
226 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
227 data = (struct inode_private_data *) channel->private_data;
228 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
229
230 if ((retval = ext2fs_file_lseek(data->file,
231 block * channel->block_size,
232 EXT2_SEEK_SET, 0)))
233 return retval;
234
235 count = (count < 0) ? -count : (count * channel->block_size);
236
237 return ext2fs_file_write(data->file, buf, count, 0);
238}
239
240static errcode_t inode_write_byte(io_channel channel, unsigned long offset,
241 int size, const void *buf)
242{
243 struct inode_private_data *data;
244 errcode_t retval = 0;
245
246 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
247 data = (struct inode_private_data *) channel->private_data;
248 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
249
250 if ((retval = ext2fs_file_lseek(data->file, offset,
251 EXT2_SEEK_SET, 0)))
252 return retval;
253
254 return ext2fs_file_write(data->file, buf, size, 0);
255}
256
257/*
258 * Flush data buffers to disk.
259 */
260static errcode_t inode_flush(io_channel channel)
261{
262 struct inode_private_data *data;
263
264 EXT2_CHECK_MAGIC(channel, EXT2_ET_MAGIC_IO_CHANNEL);
265 data = (struct inode_private_data *) channel->private_data;
266 EXT2_CHECK_MAGIC(data, EXT2_ET_MAGIC_INODE_IO_CHANNEL);
267
268 return ext2fs_file_flush(data->file);
269}
270
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