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      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 "fatblock.h"
     26 #include "fs.h"
     27 #include "utils.h"
     28 
     29 static struct fs fs;
     30 static struct ublock_ctx *ub;
     31 static int ums_lun = 0;
     32 
     33 static int fs_import(struct fs *fs,
     34 		     uint16_t cluster_size, offset_t data_size,
     35 		     offset_t *total_size_out)
     36 {
     37 	int ret;
     38 
     39 	ret = fs_init(fs, cluster_size, data_size, total_size_out);
     40 	if (ret)
     41 		return ret;
     42 
     43 	ret = import_tree(fs, ".");
     44 	if (ret)
     45 		return ret;
     46 
     47 	return 0;
     48 }
     49 
     50 
     51 
     52 static int read_callback(char *buf, uint64_t length, uint64_t offset)
     53 {
     54 	int result;
     55 	int i;
     56 
     57 	result = fs_read(&fs, buf, offset, length);
     58 	if (result == SKY_IS_FALLING) {
     59 		WARN("underlying filesystem has been modified; stopping.\n");
     60 		ublock_stop(ub);
     61 	}
     62 
     63 	return result ? -EINVAL : 0;
     64 }
     65 
     66 static int write_callback(const char *buf, uint64_t length, uint64_t offset)
     67 {
     68 	DEBUG("writing to (%llu, %llu): we are read-only\n", offset, length);
     69 
     70 	return -EINVAL;
     71 }
     72 
     73 static struct ublock_ops ops = {
     74 	.read = &read_callback,
     75 	.write = &write_callback
     76 };
     77 
     78 
     79 
     80 static int set_ums_file(int index)
     81 {
     82 	char filename[PATH_MAX];
     83 	FILE *file;
     84 
     85 	sprintf(filename, "/sys/devices/platform/usb_mass_storage/lun%d/file",
     86 	        ums_lun);
     87 	file = fopen(filename, "w");
     88 	if (!file) {
     89 		WARN("setting USB mass storage file: fopen(%s) failed: %s\n",
     90 		     filename, strerror(errno));
     91 		return -1;
     92 	}
     93 
     94 	WARN("writing '/dev/block/ublock%d' to %s.\n", index, filename);
     95 
     96 	fprintf(file, "/dev/block/ublock%d", index);
     97 
     98 	fclose(file);
     99 
    100 	return 0;
    101 }
    102 
    103 static int clear_ums_file(void)
    104 {
    105 	char filename[PATH_MAX];
    106 	FILE *file;
    107 
    108 	sprintf(filename, "/sys/devices/platform/usb_mass_storage/lun%d/file",
    109 	        ums_lun);
    110 	file = fopen(filename, "w");
    111 	if (!file) {
    112 		WARN("clearing USB mass storage file: fopen(%s) failed: %s\n",
    113 		     filename, strerror(errno));
    114 		return -1;
    115 	}
    116 
    117 	fclose(file);
    118 
    119 	return 0;
    120 }
    121 
    122 
    123 
    124 
    125 static void cleanup(void)
    126 {
    127 	WARN("cleanup: clearing USB mass storage file\n");
    128 	clear_ums_file();
    129 	WARN("cleanup: destroying block device\n");
    130 	ublock_destroy(ub);
    131 }
    132 
    133 static void signal_handler(int sig)
    134 {
    135 	WARN("received signal %d\n", sig);
    136 	cleanup();
    137 	exit(0);
    138 }
    139 
    140 static int normal_exit = 0;
    141 
    142 static void atexit_handler(void)
    143 {
    144 	if (normal_exit)
    145 		return;
    146 
    147 	cleanup();
    148 }
    149 
    150 int main(int argc, char *argv[]) {
    151 	char *path;
    152 	int mb;
    153 	offset_t total_size;
    154 	int index;
    155 	int ret;
    156 
    157 	signal(SIGINT, &signal_handler);
    158 	signal(SIGTERM, &signal_handler);
    159 	atexit(&atexit_handler);
    160 
    161 	if (argc != 3)
    162 		DIE("Usage: fatblock <path> <size in MB>\n");
    163 
    164 	path = argv[1];
    165 	mb = atoi(argv[2]);
    166 
    167 	INFO("fatblock: importing filesystem from %s (%d MB)\n", path, mb);
    168 
    169 	ret = chdir(path);
    170 	if (ret < 0)
    171 		DIE("fatblock: chdir(%s) failed: %s; aborting\n", path, strerror(errno));
    172 
    173 	ret = fs_import(&fs, 32768, 1048576LL * mb, &total_size);
    174 	if (ret)
    175 		DIE("fatblock: couldn't import filesystem; aborting\n");
    176 
    177 	INFO("fatblock: filesystem imported (%llu bytes)\n", total_size);
    178 
    179 	ret = ublock_init(&ub, &ops, total_size);
    180 	if (ret)
    181 		DIE("fatblock: couldn't create block device; aborting\n");
    182 	index = ublock_index(ub);
    183 	if (index < 0)
    184 		DIE("fatblock: invalid ublock index %d; aborting\n", index);
    185 
    186 	INFO("fatblock: block device ublock%d created\n", index);
    187 	set_ums_file(index);
    188 
    189 	INFO("fatblock: entering main loop\n");
    190 	ublock_run(ub);
    191 
    192 	INFO("fatblock: destroying block device\n");
    193 	clear_ums_file();
    194 	ublock_destroy(ub);
    195 
    196 	normal_exit = 1;
    197 
    198 	INFO("fatblock: goodbye!\n");
    199 	return 0;
    200 }
    201