mirror of
https://gitlab.com/sortix/sortix.git
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274 lines
7 KiB
C++
274 lines
7 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2013.
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This program is free software: you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the Free
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Software Foundation, either version 3 of the License, or (at your option)
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any later version.
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This program is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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more details.
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You should have received a copy of the GNU General Public License along with
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this program. If not, see <http://www.gnu.org/licenses/>.
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mbrfs.cpp
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Creates block devices representing master boot record partitions.
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*******************************************************************************/
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#include <endian.h>
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#include <errno.h>
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#include <error.h>
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#include <fcntl.h>
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#include <ioleast.h>
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#include <stdio.h>
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#include <stdint.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include <fsmarshall.h>
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struct partition
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{
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little_uint8_t flags;
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little_uint8_t start_head;
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little_uint16_t start_sector_cylinder;
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little_uint8_t system_id;
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little_uint8_t end_head;
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little_uint16_t end_sector_cylinder;
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little_uint32_t start_sector;
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little_uint32_t total_sectors;
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} __attribute__((packed));
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struct partition_lba48
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{
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little_uint8_t flags;
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little_uint8_t signature1;
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little_uint16_t start_sector_high;
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little_uint8_t system_id;
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little_uint8_t signature2;
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little_uint16_t total_sectors_high;
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little_uint32_t start_sector;
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little_uint32_t total_sectors;
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} __attribute__((packed));
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struct mbr
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{
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uint8_t bootstrap[436];
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uint8_t unique_disk_id[10];
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struct partition partitions[4];
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uint8_t signature[2];
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} __attribute__((packed));
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bool memiszero(const void* mem, size_t size)
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{
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for ( size_t i = 0; i < size; i++ )
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if ( ((const uint8_t*) mem)[i] )
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return false;
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return true;
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}
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bool is_48bit_lba_partition(const struct partition* partition)
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{
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const struct partition_lba48* partition_lba48 =
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(const struct partition_lba48*) partition;
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return partition_lba48->flags & 0x1 &&
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partition_lba48->signature1 == 0x14 &&
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partition_lba48->signature2 == 0xeb;
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}
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bool is_extended_partition(const struct partition* partition)
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{
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return partition->system_id == 0x5 || partition->system_id == 0xF;
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}
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uint64_t partition_get_start(const struct partition* partition)
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{
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if ( !is_48bit_lba_partition(partition) )
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return (uint64_t) partition->start_sector * 512;
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const struct partition_lba48* partition_lba48 =
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(const struct partition_lba48*) partition;
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uint64_t lower = partition_lba48->start_sector;
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uint64_t higher = partition_lba48->start_sector_high;
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return ((higher << 32) + lower) * 512;
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}
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uint64_t partition_get_length(const struct partition* partition)
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{
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if ( !is_48bit_lba_partition(partition) )
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return (uint64_t) partition->total_sectors * 512;
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const struct partition_lba48* partition_lba48 =
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(const struct partition_lba48*) partition;
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uint64_t lower = partition_lba48->total_sectors;
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uint64_t higher = partition_lba48->total_sectors_high;
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return ((higher << 32) + lower) * 512;
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}
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bool is_partition_used(const struct partition* partition)
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{
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if ( memiszero(partition, sizeof(*partition)) )
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return false;
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if ( !partition->system_id )
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return false;
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if ( !partition_get_start(partition) )
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return false;
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if ( !partition_get_length(partition) )
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return false;
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return true;
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}
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bool verify_is_partition(const struct partition* partition)
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{
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if ( memiszero(partition, sizeof(*partition)) )
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return true;
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return true;
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}
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bool verify_is_mbr(const struct mbr* mbr)
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{
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if ( memiszero(mbr, sizeof(*mbr)) )
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return false;
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if ( !(mbr->signature[0] == 0x55 && mbr->signature[1] == 0xAA) )
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return false;
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bool found_extended = false;
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for ( size_t i = 0; i < 4; i++ )
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{
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const struct partition* partition = &mbr->partitions[i];
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if ( !verify_is_partition(partition) )
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return false;
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if ( is_extended_partition(partition) )
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{
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if ( found_extended )
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return false;
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found_extended = true;
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}
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}
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return true;
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}
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int create_partition_block_device(const char* path, int diskfd, off_t start,
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off_t length)
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{
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int ret = -1, mountfd, partfd;
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// Make sure that is a file that we can mount bind us on.
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if ( 0 <= (mountfd = open(path, O_RDONLY | O_CREAT, 0666)) )
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{
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// Create a file descriptor for our new partition.
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if ( 0 <= (partfd = mkpartition(diskfd, start, length)) )
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{
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ret = fsm_fsbind(partfd, mountfd, 0);
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close(partfd);
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}
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close(mountfd);
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}
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return ret;
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}
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void Usage(FILE* fp, const char* argv0)
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{
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fprintf(fp, "Usage: %s [--probe] DEVICE...\n", argv0);
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}
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void Help(FILE* fp, const char* argv0)
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{
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Usage(fp, argv0);
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}
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void Version(FILE* fp, const char* argv0)
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{
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Usage(fp, argv0);
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}
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int main(int argc, char* argv[])
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{
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const char* argv0 = argv[0];
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bool probe = false;
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for ( int i = 1; i < argc; i++ )
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{
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const char* arg = argv[i];
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if ( arg[0] != '-' )
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continue;
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argv[i] = NULL;
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if ( !strcmp(arg, "--") )
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break;
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if ( arg[1] != '-' )
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{
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while ( char c = *++arg ) switch ( c )
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{
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default:
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fprintf(stderr, "%s: unknown option -- '%c'\n", argv0, c);
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Usage(stderr, argv0);
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exit(1);
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}
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}
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else if ( !strcmp(arg, "--help") ) { Help(stdout, argv0); exit(0); }
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else if ( !strcmp(arg, "--usage") ) { Usage(stdout, argv0); exit(0); }
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else if ( !strcmp(arg, "--version") ) { Version(stdout, argv0); exit(0); }
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else if ( !strcmp(arg, "--probe") )
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probe = true;
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else
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{
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fprintf(stderr, "%s: unknown option: %s\n", argv0, arg);
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Usage(stderr, argv0);
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exit(1);
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}
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}
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if ( argc == 1 )
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{
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Usage(stderr, argv0);
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exit(0);
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}
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for ( int i = 1; i < argc; i++ )
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{
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if ( !argv[i] )
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continue;
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const char* path = argv[i];
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size_t path_len = strlen(path);
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int fd = open(path, O_RDWR);
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if ( fd < 0 )
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error(1, errno, "`%s'", path);
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struct mbr mbr;
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size_t amount = preadall(fd, &mbr, sizeof(mbr), 0);
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if ( amount < sizeof(mbr) && errno != EEOF )
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error(1, errno, "read: `%s'", path);
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if ( amount < sizeof(mbr) || !verify_is_mbr(&mbr) )
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{
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if ( probe )
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exit(1);
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error(1, 0, "`%s': No valid master boot record detected", path);
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}
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for ( size_t i = 0; !probe && i < 4; i++ )
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{
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struct partition* partition = &mbr.partitions[i];
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if ( !is_partition_used(partition) )
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continue;
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// TODO: Support extended partitions!
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if ( is_extended_partition(partition) )
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continue;
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uint64_t start = partition_get_start(partition);
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uint64_t length = partition_get_length(partition);
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size_t device_name_len = path_len + 1 + sizeof(size_t) * 3;
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char* device_name = new char[device_name_len+1];
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snprintf(device_name, device_name_len, "%sp%zu", path, i+1);
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if ( create_partition_block_device(device_name, fd, start, length) != 0 )
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error(1, errno, "creating `%s'", device_name);
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printf("%s\n", device_name);
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delete[] device_name;
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}
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close(fd);
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}
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return 0;
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}
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