cb72aa1809
reading large extents and decrease amount of blocklist hook calls.
160 lines
4 KiB
C
160 lines
4 KiB
C
/* blocklist.c - print the block list of a file */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2006,2007 Free Software Foundation, Inc.
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*
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* GRUB is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* GRUB is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <grub/dl.h>
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#include <grub/misc.h>
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#include <grub/file.h>
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#include <grub/mm.h>
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#include <grub/disk.h>
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#include <grub/partition.h>
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#include <grub/command.h>
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#include <grub/i18n.h>
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GRUB_MOD_LICENSE ("GPLv3+");
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/* Context for grub_cmd_blocklist. */
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struct blocklist_ctx
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{
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unsigned long start_sector;
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unsigned num_sectors;
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int num_entries;
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grub_disk_addr_t part_start;
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};
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/* Helper for grub_cmd_blocklist. */
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static void
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print_blocklist (grub_disk_addr_t sector, unsigned num,
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unsigned offset, unsigned length, struct blocklist_ctx *ctx)
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{
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if (ctx->num_entries++)
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grub_printf (",");
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grub_printf ("%llu", (unsigned long long) (sector - ctx->part_start));
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if (num > 0)
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grub_printf ("+%u", num);
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if (offset != 0 || length != 0)
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grub_printf ("[%u-%u]", offset, offset + length);
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}
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/* Helper for grub_cmd_blocklist. */
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static void
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read_blocklist (grub_disk_addr_t sector, unsigned offset, unsigned length,
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void *data)
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{
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struct blocklist_ctx *ctx = data;
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if (ctx->num_sectors > 0)
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{
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if (ctx->start_sector + ctx->num_sectors == sector
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&& offset == 0 && length >= GRUB_DISK_SECTOR_SIZE)
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{
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ctx->num_sectors += length >> GRUB_DISK_SECTOR_BITS;
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sector += length >> GRUB_DISK_SECTOR_BITS;
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length &= (GRUB_DISK_SECTOR_SIZE - 1);
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}
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if (!length)
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return;
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print_blocklist (ctx->start_sector, ctx->num_sectors, 0, 0, ctx);
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ctx->num_sectors = 0;
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}
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if (offset)
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{
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unsigned l = length + offset;
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l &= (GRUB_DISK_SECTOR_SIZE - 1);
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l -= offset;
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print_blocklist (sector, 0, offset, l, ctx);
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length -= l;
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sector++;
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offset = 0;
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}
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if (!length)
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return;
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if (length & (GRUB_DISK_SECTOR_SIZE - 1))
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{
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if (length >> GRUB_DISK_SECTOR_BITS)
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{
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print_blocklist (sector, length >> GRUB_DISK_SECTOR_BITS, 0, 0, ctx);
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sector += length >> GRUB_DISK_SECTOR_BITS;
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}
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print_blocklist (sector, 0, 0, length & (GRUB_DISK_SECTOR_SIZE - 1), ctx);
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}
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else
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{
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ctx->start_sector = sector;
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ctx->num_sectors = length >> GRUB_DISK_SECTOR_BITS;
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}
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}
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static grub_err_t
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grub_cmd_blocklist (grub_command_t cmd __attribute__ ((unused)),
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int argc, char **args)
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{
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grub_file_t file;
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char buf[GRUB_DISK_SECTOR_SIZE];
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struct blocklist_ctx ctx = {
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.start_sector = 0,
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.num_sectors = 0,
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.num_entries = 0,
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.part_start = 0
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};
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if (argc < 1)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
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grub_file_filter_disable_compression ();
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file = grub_file_open (args[0]);
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if (! file)
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return grub_errno;
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if (! file->device->disk)
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return grub_error (GRUB_ERR_BAD_DEVICE,
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"this command is available only for disk devices");
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ctx.part_start = grub_partition_get_start (file->device->disk->partition);
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file->read_hook = read_blocklist;
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file->read_hook_data = &ctx;
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while (grub_file_read (file, buf, sizeof (buf)) > 0)
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;
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if (ctx.num_sectors > 0)
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print_blocklist (ctx.start_sector, ctx.num_sectors, 0, 0, &ctx);
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grub_file_close (file);
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return grub_errno;
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}
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static grub_command_t cmd;
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GRUB_MOD_INIT(blocklist)
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{
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cmd = grub_register_command ("blocklist", grub_cmd_blocklist,
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N_("FILE"), N_("Print a block list."));
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}
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GRUB_MOD_FINI(blocklist)
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{
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grub_unregister_command (cmd);
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}
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