123 lines
3.4 KiB
C
123 lines
3.4 KiB
C
/* fwconfig.c - command to read config from qemu fwconfig */
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/*
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* GRUB -- GRand Unified Bootloader
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* Copyright (C) 2015 CoreOS, 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/extcmd.h>
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#include <grub/env.h>
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#include <grub/cpu/io.h>
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#include <grub/i18n.h>
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#include <grub/mm.h>
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GRUB_MOD_LICENSE ("GPLv3+");
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#define SELECTOR 0x510
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#define DATA 0x511
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#define SIGNATURE_INDEX 0x00
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#define DIRECTORY_INDEX 0x19
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static grub_extcmd_t cmd_read_fwconfig;
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struct grub_qemu_fwcfgfile {
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grub_uint32_t size;
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grub_uint16_t select;
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grub_uint16_t reserved;
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char name[56];
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};
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static const struct grub_arg_option options[] =
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{
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{0, 'v', 0, N_("Save read value into variable VARNAME."),
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N_("VARNAME"), ARG_TYPE_STRING},
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{0, 0, 0, 0, 0, 0}
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};
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static grub_err_t
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grub_cmd_fwconfig (grub_extcmd_context_t ctxt __attribute__ ((unused)),
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int argc, char **argv)
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{
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grub_uint32_t i, j, value = 0;
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struct grub_qemu_fwcfgfile file;
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char fwsig[4], signature[4] = { 'Q', 'E', 'M', 'U' };
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if (argc != 2)
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return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("two arguments expected"));
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/* Verify that we have meaningful hardware here */
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grub_outw(SIGNATURE_INDEX, SELECTOR);
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for (i=0; i<sizeof(fwsig); i++)
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fwsig[i] = grub_inb(DATA);
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if (grub_memcmp(fwsig, signature, sizeof(signature)) != 0)
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return grub_error (GRUB_ERR_BAD_DEVICE, N_("invalid fwconfig hardware signature: got 0x%x%x%x%x"), fwsig[0], fwsig[1], fwsig[2], fwsig[3]);
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/* Find out how many file entries we have */
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grub_outw(DIRECTORY_INDEX, SELECTOR);
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value = grub_inb(DATA) | grub_inb(DATA) << 8 | grub_inb(DATA) << 16 | grub_inb(DATA) << 24;
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value = grub_be_to_cpu32(value);
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/* Read the file description for each file */
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for (i=0; i<value; i++)
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{
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for (j=0; j<sizeof(file); j++)
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{
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((char *)&file)[j] = grub_inb(DATA);
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}
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/* Check whether it matches what we're looking for, and if so read the file */
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if (grub_strncmp(file.name, argv[0], sizeof(file.name)) == 0)
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{
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grub_uint32_t filesize = grub_be_to_cpu32(file.size);
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grub_uint16_t location = grub_be_to_cpu16(file.select);
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char *data = grub_malloc(filesize+1);
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if (!data)
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return grub_error (GRUB_ERR_OUT_OF_MEMORY, N_("can't allocate buffer for data"));
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grub_outw(location, SELECTOR);
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for (j=0; j<filesize; j++)
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{
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data[j] = grub_inb(DATA);
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}
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data[filesize] = '\0';
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grub_env_set (argv[1], data);
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grub_free(data);
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return 0;
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}
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}
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return grub_error (GRUB_ERR_FILE_NOT_FOUND, N_("couldn't find entry %s"), argv[0]);
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}
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GRUB_MOD_INIT(fwconfig)
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{
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cmd_read_fwconfig =
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grub_register_extcmd ("fwconfig", grub_cmd_fwconfig, 0,
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N_("PATH VAR"),
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N_("Set VAR to the contents of fwconfig PATH"),
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options);
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}
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GRUB_MOD_FINI(fwconfig)
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{
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grub_unregister_extcmd (cmd_read_fwconfig);
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}
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