fatblock.c revision f79b2dff1024db4f6326f3422236bed169dd902f 
1/*
2 * Copyright (C) 2010 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include <assert.h>
18#include <errno.h>
19#include <stdint.h>
20#include <stdio.h>
21#include <unistd.h>
22
23#include <ublock/ublock.h>
24
25#include "errors.h"
26#include "import.h"
27#include "fs.h"
28#include "read.h"
29#include "utils.h"
30
31static struct fs fs;
32static struct ublock_ctx *ub;
33static int ums_lun = 0;
34
35static int fs_import(struct fs *fs, uint16_t cluster_size, offset_t data_size, offset_t *total_size_out) {
36	int ret;
37
38	ret = fs_init(fs, cluster_size, data_size, total_size_out);
39	if (ret)
40		return ret;
41
42	ret = import_tree(fs, ".");
43	if (ret)
44		return ret;
45
46	return 0;
47}
48
49
50
51static int read_callback(char *buf, uint64_t length, uint64_t offset) {
52	int result;
53	int i;
54
55	result = fs_read(&fs, buf, offset, length);
56	if (result == SKY_IS_FALLING) {
57		WARN("underlying filesystem has been modified; stopping.\n");
58		ublock_stop(ub);
59	}
60
61	return result ? -EINVAL : 0;
62}
63
64static int write_callback(const char *buf, uint64_t length, uint64_t offset) {
65	DEBUG("writing to (%llu, %llu): we are read-only\n", offset, length);
66
67	return -EINVAL;
68}
69
70static struct ublock_ops ops = {
71	.read = &read_callback,
72	.write = &write_callback
73};
74
75
76
77static int set_ums_file(int index)
78{
79	char filename[PATH_MAX];
80	FILE *file;
81
82	sprintf(filename, "/sys/devices/platform/usb_mass_storage/lun%d/file", ums_lun);
83	file = fopen(filename, "w");
84	if (!file) {
85		WARN("setting USB mass storage file: fopen(%s) failed: %s\n", filename, strerror(errno));
86		return -1;
87	}
88
89	WARN("writing '/dev/block/ublock%d' to %s.\n", index, filename);
90
91	fprintf(file, "/dev/block/ublock%d", index);
92
93	fclose(file);
94
95	return 0;
96}
97
98static int clear_ums_file(void)
99{
100	char filename[PATH_MAX];
101	FILE *file;
102
103	sprintf(filename, "/sys/devices/platform/usb_mass_storage/lun%d/file", ums_lun);
104	file = fopen(filename, "w");
105	if (!file) {
106		WARN("clearing USB mass storage file: fopen(%s) failed: %s\n", filename, strerror(errno));
107		return -1;
108	}
109
110	fclose(file);
111
112	return 0;
113}
114
115
116
117
118static void cleanup(void)
119{
120	WARN("cleanup: clearing USB mass storage file\n");
121	clear_ums_file();
122	WARN("cleanup: destroying block device\n");
123	ublock_destroy(ub);
124}
125
126static void signal_handler(int sig)
127{
128	WARN("received signal %d\n", sig);
129	cleanup();
130	exit(0);
131}
132
133static int normal_exit = 0;
134
135static void atexit_handler(void)
136{
137	if (normal_exit)
138		return;
139
140	cleanup();
141}
142
143int main(int argc, char *argv[]) {
144	char *path;
145	int mb;
146	offset_t total_size;
147	int index;
148	int ret;
149
150	signal(SIGINT, &signal_handler);
151	signal(SIGTERM, &signal_handler);
152	atexit(&atexit_handler);
153
154	if (argc != 3)
155		DIE("Usage: fatblock <path> <size in MB>\n");
156
157	path = argv[1];
158	mb = atoi(argv[2]);
159
160	INFO("fatblock: importing filesystem from %s (%d MB)\n", path, mb);
161
162	ret = chdir(path);
163	if (ret < 0)
164		DIE("fatblock: chdir(%s) failed: %s; aborting\n", path, strerror(errno));
165
166	ret = fs_import(&fs, 32768, 1048576LL * mb, &total_size);
167	if (ret)
168		DIE("fatblock: couldn't import filesystem; aborting\n");
169
170	INFO("fatblock: filesystem imported (%llu bytes)\n", total_size);
171
172	ret = ublock_init(&ub, &ops, total_size);
173	if (ret)
174		DIE("fatblock: couldn't create block device; aborting\n");
175	index = ublock_index(ub);
176	if (index < 0)
177		DIE("fatblock: invalid ublock index %d; aborting\n", index);
178
179	INFO("fatblock: block device ublock%d created\n", index);
180	set_ums_file(index);
181
182	INFO("fatblock: entering main loop\n");
183	ublock_run(ub);
184
185	INFO("fatblock: destroying block device\n");
186	clear_ums_file();
187	ublock_destroy(ub);
188
189	normal_exit = 1;
190
191	INFO("fatblock: goodbye!\n");
192	return 0;
193}
194