diff options
| -rw-r--r-- | src/config/Options.lb | 5 | ||||
| -rw-r--r-- | src/include/fs/fat.h | 100 | ||||
| -rw-r--r-- | src/stream/fs/Config.lb | 8 | ||||
| -rw-r--r-- | src/stream/fs/fat.c | 498 |
4 files changed, 611 insertions, 0 deletions
diff --git a/src/config/Options.lb b/src/config/Options.lb index 2064ffc2ef..8646eb8d9b 100644 --- a/src/config/Options.lb +++ b/src/config/Options.lb @@ -537,6 +537,11 @@ define CONFIG_FS_ISO9660 export always comment "Enable ISO9660 filesystem support" end +define CONFIG_FS_FAT + default 0 + export always + comment "Enable FAT filesystem support" +end define AUTOBOOT_DELAY default 2 export always diff --git a/src/include/fs/fat.h b/src/include/fs/fat.h new file mode 100644 index 0000000000..7fed6bacb3 --- /dev/null +++ b/src/include/fs/fat.h @@ -0,0 +1,100 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2001 Free Software Foundation, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + + +/* + * Defines for the FAT BIOS Parameter Block (embedded in the first block + * of the partition. + */ + +typedef __signed__ char __s8; +typedef unsigned char __u8; +typedef __signed__ short __s16; +typedef unsigned short __u16; +typedef __signed__ int __s32; +typedef unsigned int __u32; + +/* Note that some shorts are not aligned, and must therefore + * be declared as array of two bytes. + */ +struct fat_bpb { + __s8 ignored[3]; /* Boot strap short or near jump */ + __s8 system_id[8]; /* Name - can be used to special case + partition manager volumes */ + __u8 bytes_per_sect[2]; /* bytes per logical sector */ + __u8 sects_per_clust;/* sectors/cluster */ + __u8 reserved_sects[2]; /* reserved sectors */ + __u8 num_fats; /* number of FATs */ + __u8 dir_entries[2]; /* root directory entries */ + __u8 short_sectors[2]; /* number of sectors */ + __u8 media; /* media code (unused) */ + __u16 fat_length; /* sectors/FAT */ + __u16 secs_track; /* sectors per track */ + __u16 heads; /* number of heads */ + __u32 hidden; /* hidden sectors (unused) */ + __u32 long_sectors; /* number of sectors (if short_sectors == 0) */ + + /* The following fields are only used by FAT32 */ + __u32 fat32_length; /* sectors/FAT */ + __u16 flags; /* bit 8: fat mirroring, low 4: active fat */ + __u8 version[2]; /* major, minor filesystem version */ + __u32 root_cluster; /* first cluster in root directory */ + __u16 info_sector; /* filesystem info sector */ + __u16 backup_boot; /* backup boot sector */ + __u16 reserved2[6]; /* Unused */ +}; + +#define FAT_CVT_U16(bytarr) (* (__u16*)(bytarr)) + +/* + * Defines how to differentiate a 12-bit and 16-bit FAT. + */ + +#define FAT_MAX_12BIT_CLUST 4087 /* 4085 + 2 */ + +/* + * Defines for the file "attribute" byte + */ + +#define FAT_ATTRIB_OK_MASK 0x37 +#define FAT_ATTRIB_NOT_OK_MASK 0xC8 +#define FAT_ATTRIB_DIR 0x10 +#define FAT_ATTRIB_LONGNAME 0x0F + +/* + * Defines for FAT directory entries + */ + +#define FAT_DIRENTRY_LENGTH 32 + +#define FAT_DIRENTRY_ATTRIB(entry) \ + (*((unsigned char *) (entry+11))) +#define FAT_DIRENTRY_VALID(entry) \ + ( ((*((unsigned char *) entry)) != 0) \ + && ((*((unsigned char *) entry)) != 0xE5) \ + && !(FAT_DIRENTRY_ATTRIB(entry) & FAT_ATTRIB_NOT_OK_MASK) ) +#define FAT_DIRENTRY_FIRST_CLUSTER(entry) \ + ((*((unsigned short *) (entry+26)))+(*((unsigned short *) (entry+20)) << 16)) +#define FAT_DIRENTRY_FILELENGTH(entry) \ + (*((unsigned long *) (entry+28))) + +#define FAT_LONGDIR_ID(entry) \ + (*((unsigned char *) (entry))) +#define FAT_LONGDIR_ALIASCHECKSUM(entry) \ + (*((unsigned char *) (entry+13))) diff --git a/src/stream/fs/Config.lb b/src/stream/fs/Config.lb index 43c18c57a8..86d81f0dcc 100644 --- a/src/stream/fs/Config.lb +++ b/src/stream/fs/Config.lb @@ -1,3 +1,7 @@ +uses CONFIG_FS_EXT2 +uses CONFIG_FS_ISO9660 +uses CONFIG_FS_FAT + object blockdev.o object vfs.o @@ -8,3 +12,7 @@ end if CONFIG_FS_ISO9660 object iso9660.o end + +if CONFIG_FS_FAT + object fat.o +end diff --git a/src/stream/fs/fat.c b/src/stream/fs/fat.c new file mode 100644 index 0000000000..b657bfa3f6 --- /dev/null +++ b/src/stream/fs/fat.c @@ -0,0 +1,498 @@ +/* + * GRUB -- GRand Unified Bootloader + * Copyright (C) 2000, 2001 Free Software Foundation, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. + */ + +#include <fs/fs.h> +#include <fs/fat.h> + +struct fat_superblock +{ + int fat_offset; + int fat_length; + int fat_size; + int root_offset; + int root_max; + int data_offset; + + int num_sectors; + int num_clust; + int clust_eof_marker; + int sects_per_clust; + int sectsize_bits; + int clustsize_bits; + int root_cluster; + + int cached_fat; + int file_cluster; + int current_cluster_num; + int current_cluster; +}; + +/* pointer(s) into filesystem info buffer for DOS stuff */ +#define FAT_SUPER ( (struct fat_superblock *) \ + ( FSYS_BUF + 32256) )/* 512 bytes long */ +#define FAT_BUF ( FSYS_BUF + 30208 ) /* 4 sector FAT buffer */ +#define NAME_BUF ( FSYS_BUF + 29184 ) /* Filename buffer (833 bytes) */ + +#define FAT_CACHE_SIZE 2048 + +#ifndef PPC +static __inline__ unsigned long +log2 (unsigned long word) +{ + __asm__ ("bsfl %1,%0" + : "=r" (word) + : "r" (word)); + return word; +} +#else /* !PPC */ +static __inline__ unsigned long +__ilog2(unsigned long x) +{ + unsigned long lz; + + asm ("cntlzw %0,%1" : "=r" (lz) : "r" (x)); + return 31 - lz; +} +static __inline__ unsigned long +log2(unsigned long x) +{ + if ((x = ~x) == 0) + return 32; + return __ilog2(x & -x); +} +#endif + +int +fat_mount (void) +{ + struct fat_bpb bpb; + __u32 magic, first_fat; + + /* Check partition type for harddisk */ + if (((current_drive & 0x80) || (current_slice != 0)) + && ! IS_PC_SLICE_TYPE_FAT (current_slice) + && (! IS_PC_SLICE_TYPE_BSD_WITH_FS (current_slice, FS_MSDOS))) + return 0; + + /* Read bpb */ + if (! devread (0, 0, sizeof (bpb), (char *) &bpb)) + return 0; + + /* Check if the number of sectors per cluster is zero here, to avoid + zero division. */ + if (bpb.sects_per_clust == 0) + return 0; + + FAT_SUPER->sectsize_bits = log2 (FAT_CVT_U16 (bpb.bytes_per_sect)); + FAT_SUPER->clustsize_bits + = FAT_SUPER->sectsize_bits + log2 (bpb.sects_per_clust); + + /* Fill in info about super block */ + FAT_SUPER->num_sectors = FAT_CVT_U16 (bpb.short_sectors) + ? FAT_CVT_U16 (bpb.short_sectors) : bpb.long_sectors; + + /* FAT offset and length */ + FAT_SUPER->fat_offset = FAT_CVT_U16 (bpb.reserved_sects); + FAT_SUPER->fat_length = + bpb.fat_length ? bpb.fat_length : bpb.fat32_length; + + /* Rootdir offset and length for FAT12/16 */ + FAT_SUPER->root_offset = + FAT_SUPER->fat_offset + bpb.num_fats * FAT_SUPER->fat_length; + FAT_SUPER->root_max = FAT_DIRENTRY_LENGTH * FAT_CVT_U16(bpb.dir_entries); + + /* Data offset and number of clusters */ + FAT_SUPER->data_offset = + FAT_SUPER->root_offset + + ((FAT_SUPER->root_max - 1) >> FAT_SUPER->sectsize_bits) + 1; + FAT_SUPER->num_clust = + 2 + ((FAT_SUPER->num_sectors - FAT_SUPER->data_offset) + / bpb.sects_per_clust); + FAT_SUPER->sects_per_clust = bpb.sects_per_clust; + + if (!bpb.fat_length) + { + /* This is a FAT32 */ + if (FAT_CVT_U16(bpb.dir_entries)) + return 0; + + if (bpb.flags & 0x0080) + { + /* FAT mirroring is disabled, get active FAT */ + int active_fat = bpb.flags & 0x000f; + if (active_fat >= bpb.num_fats) + return 0; + FAT_SUPER->fat_offset += active_fat * FAT_SUPER->fat_length; + } + + FAT_SUPER->fat_size = 8; + FAT_SUPER->root_cluster = bpb.root_cluster; + + /* Yes the following is correct. FAT32 should be called FAT28 :) */ + FAT_SUPER->clust_eof_marker = 0xffffff8; + } + else + { + if (!FAT_SUPER->root_max) + return 0; + + FAT_SUPER->root_cluster = -1; + if (FAT_SUPER->num_clust > FAT_MAX_12BIT_CLUST) + { + FAT_SUPER->fat_size = 4; + FAT_SUPER->clust_eof_marker = 0xfff8; + } + else + { + FAT_SUPER->fat_size = 3; + FAT_SUPER->clust_eof_marker = 0xff8; + } + } + + + /* Now do some sanity checks */ + + if (FAT_CVT_U16(bpb.bytes_per_sect) != (1 << FAT_SUPER->sectsize_bits) + || FAT_CVT_U16(bpb.bytes_per_sect) != SECTOR_SIZE + || bpb.sects_per_clust != (1 << (FAT_SUPER->clustsize_bits + - FAT_SUPER->sectsize_bits)) + || FAT_SUPER->num_clust <= 2 + || (FAT_SUPER->fat_size * FAT_SUPER->num_clust / (2 * SECTOR_SIZE) + > FAT_SUPER->fat_length)) + return 0; + + /* kbs: Media check on first FAT entry [ported from PUPA] */ + + if (!devread(FAT_SUPER->fat_offset, 0, + sizeof(first_fat), (char *)&first_fat)) + return 0; + + if (FAT_SUPER->fat_size == 8) + { + first_fat &= 0x0fffffff; + magic = 0x0fffff00; + } + else if (FAT_SUPER->fat_size == 4) + { + first_fat &= 0x0000ffff; + magic = 0xff00; + } + else + { + first_fat &= 0x00000fff; + magic = 0x0f00; + } + + if (first_fat != (magic | bpb.media)) + return 0; + + FAT_SUPER->cached_fat = - 2 * FAT_CACHE_SIZE; + return 1; +} + +int +fat_read (char *buf, int len) +{ + int logical_clust; + int offset; + int ret = 0; + int size; + + if (FAT_SUPER->file_cluster < 0) + { + /* root directory for fat16 */ + size = FAT_SUPER->root_max - filepos; + if (size > len) + size = len; + if (!devread(FAT_SUPER->root_offset, filepos, size, buf)) + return 0; + filepos += size; + return size; + } + + logical_clust = filepos >> FAT_SUPER->clustsize_bits; + offset = (filepos & ((1 << FAT_SUPER->clustsize_bits) - 1)); + if (logical_clust < FAT_SUPER->current_cluster_num) + { + FAT_SUPER->current_cluster_num = 0; + FAT_SUPER->current_cluster = FAT_SUPER->file_cluster; + } + + while (len > 0) + { + int sector; + while (logical_clust > FAT_SUPER->current_cluster_num) + { + /* calculate next cluster */ + int fat_entry = + FAT_SUPER->current_cluster * FAT_SUPER->fat_size; + int next_cluster; + int cached_pos = (fat_entry - FAT_SUPER->cached_fat); + + if (cached_pos < 0 || + (cached_pos + FAT_SUPER->fat_size) > 2*FAT_CACHE_SIZE) + { + FAT_SUPER->cached_fat = (fat_entry & ~(2*SECTOR_SIZE - 1)); + cached_pos = (fat_entry - FAT_SUPER->cached_fat); + sector = FAT_SUPER->fat_offset + + FAT_SUPER->cached_fat / (2*SECTOR_SIZE); + if (!devread (sector, 0, FAT_CACHE_SIZE, (char*) FAT_BUF)) + return 0; + } + next_cluster = * (unsigned long *) (FAT_BUF + (cached_pos >> 1)); + if (FAT_SUPER->fat_size == 3) + { + if (cached_pos & 1) + next_cluster >>= 4; + next_cluster &= 0xFFF; + } + else if (FAT_SUPER->fat_size == 4) + next_cluster &= 0xFFFF; + + if (next_cluster >= FAT_SUPER->clust_eof_marker) + return ret; + if (next_cluster < 2 || next_cluster >= FAT_SUPER->num_clust) + { + errnum = ERR_FSYS_CORRUPT; + return 0; + } + + FAT_SUPER->current_cluster = next_cluster; + FAT_SUPER->current_cluster_num++; + } + + sector = FAT_SUPER->data_offset + + ((FAT_SUPER->current_cluster - 2) << (FAT_SUPER->clustsize_bits + - FAT_SUPER->sectsize_bits)); + size = (1 << FAT_SUPER->clustsize_bits) - offset; + if (size > len) + size = len; + + disk_read_func = disk_read_hook; + + devread(sector, offset, size, buf); + + disk_read_func = NULL; + + len -= size; + buf += size; + ret += size; + filepos += size; + logical_clust++; + offset = 0; + } + return errnum ? 0 : ret; +} + +int +fat_dir (char *dirname) +{ + char *rest, ch, dir_buf[FAT_DIRENTRY_LENGTH]; + char *filename = (char *) NAME_BUF; + int attrib = FAT_ATTRIB_DIR; +#ifndef STAGE1_5 + int do_possibilities = 0; +#endif + + /* XXX I18N: + * the positions 2,4,6 etc are high bytes of a 16 bit unicode char + */ + static unsigned char longdir_pos[] = + { 1, 3, 5, 7, 9, 14, 16, 18, 20, 22, 24, 28, 30 }; + int slot = -2; + int alias_checksum = -1; + + FAT_SUPER->file_cluster = FAT_SUPER->root_cluster; + filepos = 0; + FAT_SUPER->current_cluster_num = MAXINT; + + /* main loop to find desired directory entry */ + loop: + + /* if we have a real file (and we're not just printing possibilities), + then this is where we want to exit */ + + if (!*dirname || isspace (*dirname)) + { + if (attrib & FAT_ATTRIB_DIR) + { + errnum = ERR_BAD_FILETYPE; + return 0; + } + + return 1; + } + + /* continue with the file/directory name interpretation */ + + while (*dirname == '/') + dirname++; + + if (!(attrib & FAT_ATTRIB_DIR)) + { + errnum = ERR_BAD_FILETYPE; + return 0; + } + /* Directories don't have a file size */ + filemax = MAXINT; + + for (rest = dirname; (ch = *rest) && !isspace (ch) && ch != '/'; rest++); + + *rest = 0; + +# ifndef STAGE1_5 + if (print_possibilities && ch != '/') + do_possibilities = 1; +# endif + + while (1) + { + if (fat_read (dir_buf, FAT_DIRENTRY_LENGTH) != FAT_DIRENTRY_LENGTH + || dir_buf[0] == 0) + { + if (!errnum) + { +# ifndef STAGE1_5 + if (print_possibilities < 0) + { +#if 0 + putchar ('\n'); +#endif + return 1; + } +# endif /* STAGE1_5 */ + + errnum = ERR_FILE_NOT_FOUND; + *rest = ch; + } + + return 0; + } + + if (FAT_DIRENTRY_ATTRIB (dir_buf) == FAT_ATTRIB_LONGNAME) + { + /* This is a long filename. The filename is build from back + * to front and may span multiple entries. To bind these + * entries together they all contain the same checksum over + * the short alias. + * + * The id field tells if this is the first entry (the last + * part) of the long filename, and also at which offset this + * belongs. + * + * We just write the part of the long filename this entry + * describes and continue with the next dir entry. + */ + int i, offset; + unsigned char id = FAT_LONGDIR_ID(dir_buf); + + if ((id & 0x40)) + { + id &= 0x3f; + slot = id; + filename[slot * 13] = 0; + alias_checksum = FAT_LONGDIR_ALIASCHECKSUM(dir_buf); + } + + if (id != slot || slot == 0 + || alias_checksum != FAT_LONGDIR_ALIASCHECKSUM(dir_buf)) + { + alias_checksum = -1; + continue; + } + + slot--; + offset = slot * 13; + + for (i=0; i < 13; i++) + filename[offset+i] = dir_buf[longdir_pos[i]]; + continue; + } + + if (!FAT_DIRENTRY_VALID (dir_buf)) + continue; + + if (alias_checksum != -1 && slot == 0) + { + int i; + unsigned char sum; + + slot = -2; + for (sum = 0, i = 0; i< 11; i++) + sum = ((sum >> 1) | (sum << 7)) + dir_buf[i]; + + if (sum == alias_checksum) + { +# ifndef STAGE1_5 + if (do_possibilities) + goto print_filename; +# endif /* STAGE1_5 */ + + if (substring (dirname, filename) == 0) + break; + } + } + + /* XXX convert to 8.3 filename format here */ + { + int i, j, c; + + for (i = 0; i < 8 && (c = filename[i] = tolower (dir_buf[i])) + && !isspace (c); i++); + + filename[i++] = '.'; + + for (j = 0; j < 3 && (c = filename[i + j] = tolower (dir_buf[8 + j])) + && !isspace (c); j++); + + if (j == 0) + i--; + + filename[i + j] = 0; + } + +# ifndef STAGE1_5 + if (do_possibilities) + { + print_filename: + if (substring (dirname, filename) <= 0) + { + if (print_possibilities > 0) + print_possibilities = -print_possibilities; + print_a_completion (filename); + } + continue; + } +# endif /* STAGE1_5 */ + + if (substring (dirname, filename) == 0) + break; + } + + *(dirname = rest) = ch; + + attrib = FAT_DIRENTRY_ATTRIB (dir_buf); + filemax = FAT_DIRENTRY_FILELENGTH (dir_buf); + filepos = 0; + FAT_SUPER->file_cluster = FAT_DIRENTRY_FIRST_CLUSTER (dir_buf); + FAT_SUPER->current_cluster_num = MAXINT; + + /* go back to main loop at top of function */ + goto loop; +} |