| /* mksdcard.c |
| ** |
| ** Copyright 2007, The Android Open Source Project |
| ** |
| ** Redistribution and use in source and binary forms, with or without |
| ** modification, are permitted provided that the following conditions are met: |
| ** * Redistributions of source code must retain the above copyright |
| ** notice, this list of conditions and the following disclaimer. |
| ** * Redistributions in binary form must reproduce the above copyright |
| ** notice, this list of conditions and the following disclaimer in the |
| ** documentation and/or other materials provided with the distribution. |
| ** * Neither the name of Google Inc. nor the names of its contributors may |
| ** be used to endorse or promote products derived from this software |
| ** without specific prior written permission. |
| ** |
| ** THIS SOFTWARE IS PROVIDED BY Google Inc. ``AS IS'' AND ANY EXPRESS OR |
| ** IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF |
| ** MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO |
| ** EVENT SHALL Google Inc. BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| ** PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; |
| ** OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, |
| ** WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR |
| ** OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF |
| ** ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| /* a simple and portable program used to generate a blank FAT32 image file |
| * |
| * usage: mksdcard [-l label] <size> <filename> |
| */ |
| |
| #include <time.h> |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <errno.h> |
| #include <unistd.h> |
| |
| /* believe me, you *don't* want to change these constants !! */ |
| #define BYTES_PER_SECTOR 512 |
| #define RESERVED_SECTORS 32 |
| #define BACKUP_BOOT_SECTOR 6 |
| #define NUM_FATS 2 |
| |
| typedef long long Wide; /* might be something else if you don't use GCC */ |
| typedef unsigned char Byte; |
| typedef Byte* Bytes; |
| |
| #define BYTE_(p,i) (((Bytes)(p))[(i)]) |
| |
| #define POKEB(p,v) BYTE_(p,0) = (Byte)(v) |
| #define POKES(p,v) ( BYTE_(p,0) = (Byte)(v), BYTE_(p,1) = (Byte)((v) >> 8) ) |
| #define POKEW(p,v) ( BYTE_(p,0) = (Byte)(v), BYTE_(p,1) = (Byte)((v) >> 8), BYTE_(p,2) = (Byte)((v) >> 16), BYTE_(p,3) = (Byte)((v) >> 24) ) |
| |
| static Byte s_boot_sector [ BYTES_PER_SECTOR ]; /* boot sector */ |
| static Byte s_fsinfo_sector [ BYTES_PER_SECTOR ]; /* FS Info sector */ |
| static Byte s_fat_head [ BYTES_PER_SECTOR ]; /* first FAT sector */ |
| static Byte s_zero_sector [ BYTES_PER_SECTOR ]; /* empty sector */ |
| |
| /* this is the date and time when creating the disk */ |
| static int |
| get_serial_id( void ) |
| { |
| unsigned short lo, hi, mid; |
| time_t now = time(NULL); |
| struct tm tm = gmtime( &now )[0]; |
| |
| lo = (unsigned short)(tm.tm_mday + ((tm.tm_mon+1) << 8) + (tm.tm_sec << 8)); |
| hi = (unsigned short)(tm.tm_min + (tm.tm_hour << 8) + (tm.tm_year + 1900)); |
| |
| return lo + (hi << 16); |
| } |
| |
| static int |
| get_sectors_per_cluster( Wide disk_size ) |
| { |
| Wide disk_MB = disk_size/(1024*1024); |
| |
| if (disk_MB < 260) |
| return 1; |
| |
| if (disk_MB < 8192) |
| return 4; |
| |
| if (disk_MB < 16384) |
| return 8; |
| |
| if (disk_MB < 32768) |
| return 16; |
| |
| return 32; |
| } |
| |
| static int |
| get_sectors_per_fat( Wide disk_size, int sectors_per_cluster ) |
| { |
| Wide divider; |
| |
| /* weird computation from MS - see fatgen103.doc for details */ |
| disk_size -= RESERVED_SECTORS * BYTES_PER_SECTOR; /* don't count 32 reserved sectors */ |
| disk_size /= BYTES_PER_SECTOR; /* disk size in sectors */ |
| divider = ((256 * sectors_per_cluster) + NUM_FATS) / 2; |
| |
| return (int)( (disk_size + (divider-1)) / divider ); |
| } |
| |
| static void |
| boot_sector_init( Bytes boot, Bytes info, Wide disk_size, const char* label ) |
| { |
| int sectors_per_cluster = get_sectors_per_cluster(disk_size); |
| int sectors_per_fat = get_sectors_per_fat(disk_size, sectors_per_cluster); |
| int sectors_per_disk = (int)(disk_size / BYTES_PER_SECTOR); |
| int serial_id = get_serial_id(); |
| int free_count; |
| |
| if (label == NULL) |
| label = "SDCARD"; |
| |
| POKEB(boot, 0xeb); |
| POKEB(boot+1, 0x5a); |
| POKEB(boot+2, 0x90); |
| strcpy( (char*)boot + 3, "MSWIN4.1" ); |
| POKES( boot + 0x0b, BYTES_PER_SECTOR ); /* sector size */ |
| POKEB( boot + 0xd, sectors_per_cluster ); /* sectors per cluster */ |
| POKES( boot + 0xe, RESERVED_SECTORS ); /* reserved sectors before first FAT */ |
| POKEB( boot + 0x10, NUM_FATS ); /* number of FATs */ |
| POKES( boot + 0x11, 0 ); /* max root directory entries for FAT12/FAT16, 0 for FAT32 */ |
| POKES( boot + 0x13, 0 ); /* total sectors, 0 to use 32-bit value at offset 0x20 */ |
| POKEB( boot + 0x15, 0xF8 ); /* media descriptor, 0xF8 == hard disk */ |
| POKES( boot + 0x16, 0 ); /* Sectors per FAT for FAT12/16, 0 for FAT32 */ |
| POKES( boot + 0x18, 9 ); /* Sectors per track (whatever) */ |
| POKES( boot + 0x1a, 2 ); /* Number of heads (whatever) */ |
| POKEW( boot + 0x1c, 0 ); /* Hidden sectors */ |
| POKEW( boot + 0x20, sectors_per_disk ); /* Total sectors */ |
| |
| /* extension */ |
| POKEW( boot + 0x24, sectors_per_fat ); /* Sectors per FAT */ |
| POKES( boot + 0x28, 0 ); /* FAT flags */ |
| POKES( boot + 0x2a, 0 ); /* version */ |
| POKEW( boot + 0x2c, 2 ); /* cluster number of root directory start */ |
| POKES( boot + 0x30, 1 ); /* sector number of FS information sector */ |
| POKES( boot + 0x32, BACKUP_BOOT_SECTOR ); /* sector number of a copy of this boot sector */ |
| POKEB( boot + 0x40, 0x80 ); /* physical drive number */ |
| POKEB( boot + 0x42, 0x29 ); /* extended boot signature ?? */ |
| POKEW( boot + 0x43, serial_id ); /* serial ID */ |
| strncpy( (char*)boot + 0x47, label, 11 ); /* Volume Label */ |
| memcpy( boot + 0x52, "FAT32 ", 8 ); /* FAT system type, padded with 0x20 */ |
| |
| POKEB( boot + BYTES_PER_SECTOR-2, 0x55 ); /* boot sector signature */ |
| POKEB( boot + BYTES_PER_SECTOR-1, 0xAA ); |
| |
| /* FSInfo sector */ |
| free_count = sectors_per_disk - 32 - 2*sectors_per_fat; |
| |
| POKEW( info + 0, 0x41615252 ); |
| POKEW( info + 484, 0x61417272 ); |
| POKEW( info + 488, free_count ); /* number of free clusters */ |
| POKEW( info + 492, 3 ); /* next free clusters, 0-1 reserved, 2 is used for the root dir */ |
| POKEW( info + 508, 0xAA550000 ); |
| } |
| |
| static void |
| fat_init( Bytes fat ) |
| { |
| POKEW( fat, 0x0ffffff8 ); /* reserve cluster 1, media id in low byte */ |
| POKEW( fat + 4, 0x0fffffff ); /* reserve cluster 2 */ |
| POKEW( fat + 8, 0x0fffffff ); /* end of clust chain for root dir */ |
| } |
| |
| |
| static int |
| write_sector( FILE* file, Bytes sector ) |
| { |
| return fwrite( sector, 1, 512, file ) != 512; |
| } |
| |
| static int |
| write_empty( FILE* file, Wide count ) |
| { |
| static Byte empty[64*1024]; |
| |
| count *= 512; |
| while (count > 0) { |
| int len = sizeof(empty); |
| if (len > count) |
| len = count; |
| |
| if ( fwrite( empty, 1, len, file ) != (size_t)len ) |
| return 1; |
| |
| count -= len; |
| } |
| return 0; |
| } |
| |
| static void usage (void) |
| { |
| fprintf(stderr, "mksdcard: create a blank FAT32 image to be used with the Android emulator\n" ); |
| fprintf(stderr, "usage: mksdcard [-l label] <size> <file>\n\n"); |
| fprintf(stderr, " if <size> is a simple integer, it specifies a size in bytes\n" ); |
| fprintf(stderr, " if <size> is an integer followed by 'K', it specifies a size in KiB\n" ); |
| fprintf(stderr, " if <size> is an integer followed by 'M', it specifies a size in MiB\n" ); |
| exit(1); |
| } |
| |
| int main( int argc, char** argv ) |
| { |
| Wide disk_size; |
| int sectors_per_fat; |
| int sectors_per_disk; |
| char* end; |
| const char* label = NULL; |
| FILE* f; |
| |
| for ( ; argc > 1 && argv[1][0] == '-'; argc--, argv++ ) |
| { |
| char* arg = argv[1] + 1; |
| switch (arg[0]) { |
| case 'l': |
| if (arg[1] != 0) |
| arg += 2; |
| else { |
| argc--; |
| argv++; |
| if (argc <= 1) |
| usage(); |
| arg = argv[1]; |
| } |
| label = arg; |
| break; |
| |
| default: |
| usage(); |
| } |
| } |
| |
| if (argc != 3) |
| usage(); |
| |
| disk_size = strtol( argv[1], &end, 10 ); |
| if (disk_size == 0 && errno == EINVAL) |
| usage(); |
| |
| if (*end == 'K') |
| disk_size *= 1024; |
| else if (*end == 'M') |
| disk_size *= 1024*1024; |
| |
| if (disk_size < 8*1024*1024) |
| fprintf(stderr, "### WARNING : SD Card images < 8 MB cannot be used with the Android emulator\n"); |
| |
| sectors_per_disk = disk_size / 512; |
| sectors_per_fat = get_sectors_per_fat( disk_size, get_sectors_per_cluster( disk_size ) ); |
| |
| boot_sector_init( s_boot_sector, s_fsinfo_sector, disk_size, NULL ); |
| fat_init( s_fat_head ); |
| |
| f = fopen( argv[2], "wb" ); |
| if ( !f ) { |
| fprintf(stderr, "could not create file '%s', aborting...\n", argv[2] ); |
| } |
| |
| /* here's the layout: |
| * |
| * boot_sector |
| * fsinfo_sector |
| * empty |
| * backup boot sector |
| * backup fsinfo sector |
| * RESERVED_SECTORS - 4 empty sectors (if backup sectors), or RESERVED_SECTORS - 2 (if no backup) |
| * first fat |
| * second fat |
| * zero sectors |
| */ |
| |
| if ( write_sector( f, s_boot_sector ) ) goto FailWrite; |
| if ( write_sector( f, s_fsinfo_sector ) ) goto FailWrite; |
| if ( BACKUP_BOOT_SECTOR > 0 ) { |
| if ( write_empty( f, BACKUP_BOOT_SECTOR - 2 ) ) goto FailWrite; |
| if ( write_sector( f, s_boot_sector ) ) goto FailWrite; |
| if ( write_sector( f, s_fsinfo_sector ) ) goto FailWrite; |
| if ( write_empty( f, RESERVED_SECTORS - 2 - BACKUP_BOOT_SECTOR ) ) goto FailWrite; |
| } |
| else |
| if ( write_empty( f, RESERVED_SECTORS - 2 ) ) goto FailWrite; |
| |
| if ( write_sector( f, s_fat_head ) ) goto FailWrite; |
| if ( write_empty( f, sectors_per_fat-1 ) ) goto FailWrite; |
| |
| if ( write_sector( f, s_fat_head ) ) goto FailWrite; |
| if ( write_empty( f, sectors_per_fat-1 ) ) goto FailWrite; |
| |
| if ( write_empty( f, sectors_per_disk - RESERVED_SECTORS - 2*sectors_per_fat ) ) goto FailWrite; |
| |
| fclose(f); |
| return 0; |
| |
| FailWrite: |
| fprintf(stderr, "could not write to '%s', aborting...\n", argv[2] ); |
| unlink( argv[2] ); |
| fclose(f); |
| return 1; |
| } |
