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Diffstat (limited to '')
| -rw-r--r-- | libparted/fs/udf/udf.c | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/libparted/fs/udf/udf.c b/libparted/fs/udf/udf.c new file mode 100644 index 0000000..a48a42e --- /dev/null +++ b/libparted/fs/udf/udf.c @@ -0,0 +1,175 @@ +/* + libparted - a library for manipulating disk partitions + Copyright (C) 2018-2023 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 3 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, see <http://www.gnu.org/licenses/>. +*/ + +#include <config.h> + +#include <parted/parted.h> + +/* Read bytes using ped_geometry_read() function */ +static int read_bytes (const PedGeometry* geom, void* buffer, PedSector offset, PedSector count) +{ + char* sector_buffer; + PedSector sector_offset, sector_count, buffer_offset; + + sector_offset = offset / geom->dev->sector_size; + sector_count = (offset + count + geom->dev->sector_size - 1) / geom->dev->sector_size - sector_offset; + buffer_offset = offset - sector_offset * geom->dev->sector_size; + + sector_buffer = alloca (sector_count * geom->dev->sector_size); + + if (!ped_geometry_read (geom, sector_buffer, sector_offset, sector_count)) + return 0; + + memcpy (buffer, sector_buffer + buffer_offset, count); + return 1; +} + +/* Scan VSR and check for UDF VSD */ +static int check_vrs (const PedGeometry* geom, unsigned int vsdsize) +{ + PedSector block; + PedSector offset; + unsigned char ident[5]; + + /* Check only first 64 blocks, but theoretically standard does not define upper limit */ + for (block = 0; block < 64; block++) { + /* VRS starts at fixed offset 32kB, it is independent of block size or vsd size */ + offset = 32768 + block * vsdsize; + + /* Read VSD identifier, it is at offset 1 */ + if (!read_bytes (geom, ident, offset + 1, 5)) + return 0; + + /* Check for UDF identifier */ + if (memcmp (ident, "NSR02", 5) == 0 || + memcmp (ident, "NSR03", 5) == 0) + return 1; + + /* Unknown VSD identifier means end of VRS */ + if (memcmp (ident, "BEA01", 5) != 0 && + memcmp (ident, "TEA01", 5) != 0 && + memcmp (ident, "BOOT2", 5) != 0 && + memcmp (ident, "CD001", 5) != 0 && + memcmp (ident, "CDW02", 5) != 0) + break; + } + + return 0; +} + +/* Check for UDF AVDP */ +static int check_anchor (const PedGeometry* geom, unsigned int blocksize, int rel_block) +{ + PedSector block; + unsigned char tag[16]; + + /* Negative block means relative to the end of device */ + if (rel_block < 0) { + block = geom->length * geom->dev->sector_size / blocksize; + if (block <= (PedSector)(-rel_block)) + return 0; + block -= (PedSector)(-rel_block); + if (block < 257) + return 0; + } else { + block = rel_block; + } + + if (!read_bytes (geom, tag, block * blocksize, 16)) + return 0; + + /* Check for AVDP type (0x0002) */ + if (((unsigned short)tag[0] | ((unsigned short)tag[1] << 8)) != 0x0002) + return 0; + + /* Check that location stored in AVDP matches */ + if (((unsigned long)tag[12] | ((unsigned long)tag[13] << 8) | ((unsigned long)tag[14] << 16) | ((unsigned long)tag[15] << 24)) != block) + return 0; + + return 1; +} + +/* Detect presence of UDF AVDP */ +static int detect_anchor(const PedGeometry* geom, unsigned int blocksize) +{ + /* All possible AVDP locations in preferred order */ + static int anchors[] = { 256, -257, -1, 512 }; + size_t i; + + for (i = 0; i < sizeof (anchors)/sizeof (*anchors); i++) { + if (check_anchor (geom, blocksize, anchors[i])) + return 1; + } + + return 0; +} + +/* Detect UDF filesystem, it must have VRS and AVDP */ +static int detect_udf (const PedGeometry* geom) +{ + unsigned int blocksize; + + /* VSD size is min(2048, UDF block size), check for block sizes <= 2048 */ + if (check_vrs (geom, 2048)) { + for (blocksize = 512; blocksize <= 2048; blocksize *= 2) { + if (detect_anchor (geom, blocksize)) + return 1; + } + } + + /* Check for block sizes larger then 2048, maximal theoretical block size is 32kB */ + for (blocksize = 4096; blocksize <= 32768; blocksize *= 2) { + if (!check_vrs (geom, blocksize)) + continue; + if (detect_anchor (geom, blocksize)) + return 1; + } + + return 0; +} + +PedGeometry* +udf_probe (PedGeometry* geom) +{ + if (!detect_udf (geom)) + return NULL; + + return ped_geometry_duplicate (geom); +} + +static PedFileSystemOps udf_ops = { + probe: udf_probe, +}; + +static PedFileSystemType udf_type = { + next: NULL, + ops: &udf_ops, + name: "udf", +}; + +void +ped_file_system_udf_init () +{ + ped_file_system_type_register (&udf_type); +} + +void +ped_file_system_udf_done () +{ + ped_file_system_type_unregister (&udf_type); +} |