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grub/grub-core/commands/smbios.c

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/* smbios.c - retrieve smbios information. */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2019 Free Software Foundation, Inc.
*
* GRUB 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.
*
* GRUB 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 GRUB. If not, see <http://www.gnu.org/licenses/>.
*/
#include <grub/dl.h>
#include <grub/env.h>
#include <grub/extcmd.h>
#include <grub/i18n.h>
#include <grub/misc.h>
#include <grub/mm.h>
#include <grub/smbios.h>
GRUB_MOD_LICENSE ("GPLv3+");
/* Abstract useful values found in either the SMBIOS3 or SMBIOS EPS. */
static struct {
grub_addr_t start;
grub_addr_t end;
grub_uint16_t structures;
} table_desc;
static grub_extcmd_t cmd;
/* Locate the SMBIOS entry point structure depending on the hardware. */
struct grub_smbios_eps *
grub_smbios_get_eps (void)
{
static struct grub_smbios_eps *eps = NULL;
if (eps != NULL)
return eps;
eps = grub_machine_smbios_get_eps ();
return eps;
}
/* Locate the SMBIOS3 entry point structure depending on the hardware. */
static struct grub_smbios_eps3 *
grub_smbios_get_eps3 (void)
{
static struct grub_smbios_eps3 *eps = NULL;
if (eps != NULL)
return eps;
eps = grub_machine_smbios_get_eps3 ();
return eps;
}
static char *
linux_string (const char *value)
{
char *out = grub_malloc( grub_strlen (value) + 1);
const char *src = value;
char *dst = out;
for (; *src; src++)
if (*src > ' ' && *src < 127 && *src != ':')
*dst++ = *src;
*dst = 0;
return out;
}
/*
* These functions convert values from the various SMBIOS structure field types
* into a string formatted to be returned to the user. They expect that the
* structure and offset were already validated. When the requested data is
* successfully retrieved and formatted, the pointer to the string is returned;
* otherwise, NULL is returned on failure. Don't free the result.
*/
static const char *
grub_smbios_format_byte (const grub_uint8_t *structure, grub_uint8_t offset)
{
static char buffer[sizeof ("255")];
grub_snprintf (buffer, sizeof (buffer), "%u", structure[offset]);
return (const char *)buffer;
}
static const char *
grub_smbios_format_word (const grub_uint8_t *structure, grub_uint8_t offset)
{
static char buffer[sizeof ("65535")];
grub_uint16_t value = grub_get_unaligned16 (structure + offset);
grub_snprintf (buffer, sizeof (buffer), "%u", value);
return (const char *)buffer;
}
static const char *
grub_smbios_format_dword (const grub_uint8_t *structure, grub_uint8_t offset)
{
static char buffer[sizeof ("4294967295")];
grub_uint32_t value = grub_get_unaligned32 (structure + offset);
grub_snprintf (buffer, sizeof (buffer), "%" PRIuGRUB_UINT32_T, value);
return (const char *)buffer;
}
static const char *
grub_smbios_format_qword (const grub_uint8_t *structure, grub_uint8_t offset)
{
static char buffer[sizeof ("18446744073709551615")];
grub_uint64_t value = grub_get_unaligned64 (structure + offset);
grub_snprintf (buffer, sizeof (buffer), "%" PRIuGRUB_UINT64_T, value);
return (const char *)buffer;
}
static const char *
grub_smbios_get_string (const grub_uint8_t *structure, grub_uint8_t offset)
{
const grub_uint8_t *ptr = structure + structure[1];
const grub_uint8_t *table_end = (const grub_uint8_t *)table_desc.end;
const grub_uint8_t referenced_string_number = structure[offset];
grub_uint8_t i;
/* A string referenced with zero is interpreted as unset. */
if (referenced_string_number == 0)
return NULL;
/* Search the string set. */
for (i = 1; *ptr != 0 && ptr < table_end; i++)
if (i == referenced_string_number)
{
const char *str = (const char *)ptr;
while (*ptr++ != 0)
if (ptr >= table_end)
return NULL; /* The string isn't terminated. */
return str;
}
else
while (*ptr++ != 0 && ptr < table_end);
/* The string number is greater than the number of strings in the set. */
return NULL;
}
static const char *
grub_smbios_format_uuid (const grub_uint8_t *structure, grub_uint8_t offset)
{
static char buffer[sizeof ("ffffffff-ffff-ffff-ffff-ffffffffffff")];
const grub_uint8_t *f = structure + offset; /* little-endian fields */
const grub_uint8_t *g = f + 8; /* byte-by-byte fields */
grub_snprintf (buffer, sizeof (buffer),
"%02x%02x%02x%02x-%02x%02x-%02x%02x-"
"%02x%02x-%02x%02x%02x%02x%02x%02x",
f[3], f[2], f[1], f[0], f[5], f[4], f[7], f[6],
g[0], g[1], g[2], g[3], g[4], g[5], g[6], g[7]);
return (const char *)buffer;
}
/* List the field formatting functions and the number of bytes they need. */
static const struct {
const char *(*format) (const grub_uint8_t *structure, grub_uint8_t offset);
grub_uint8_t field_length;
} field_extractors[] = {
{grub_smbios_format_byte, 1},
{grub_smbios_format_word, 2},
{grub_smbios_format_dword, 4},
{grub_smbios_format_qword, 8},
{grub_smbios_get_string, 1},
{grub_smbios_format_uuid, 16}
};
/* List command options, with structure field getters ordered as above. */
#define FIRST_GETTER_OPT (3)
#define SETTER_OPT (FIRST_GETTER_OPT + ARRAY_SIZE(field_extractors))
#define LINUX_OPT (FIRST_GETTER_OPT + ARRAY_SIZE(field_extractors) + 1)
static const struct grub_arg_option options[] = {
{"type", 't', 0, N_("Match structures with the given type."),
N_("type"), ARG_TYPE_INT},
{"handle", 'h', 0, N_("Match structures with the given handle."),
N_("handle"), ARG_TYPE_INT},
{"match", 'm', 0, N_("Select a structure when several match."),
N_("match"), ARG_TYPE_INT},
{"get-byte", 'b', 0, N_("Get the byte's value at the given offset."),
N_("offset"), ARG_TYPE_INT},
{"get-word", 'w', 0, N_("Get two bytes' value at the given offset."),
N_("offset"), ARG_TYPE_INT},
{"get-dword", 'd', 0, N_("Get four bytes' value at the given offset."),
N_("offset"), ARG_TYPE_INT},
{"get-qword", 'q', 0, N_("Get eight bytes' value at the given offset."),
N_("offset"), ARG_TYPE_INT},
{"get-string", 's', 0, N_("Get the string specified at the given offset."),
N_("offset"), ARG_TYPE_INT},
{"get-uuid", 'u', 0, N_("Get the UUID's value at the given offset."),
N_("offset"), ARG_TYPE_INT},
{"set", '\0', 0, N_("Store the value in the given variable name."),
N_("variable"), ARG_TYPE_STRING},
{"linux", '\0', 0, N_("Filter the result like linux does."),
N_("variable"), ARG_TYPE_NONE},
{0, 0, 0, 0, 0, 0}
};
/*
* Return a matching SMBIOS structure.
*
* This method can use up to three criteria for selecting a structure:
* - The "type" field (use -1 to ignore)
* - The "handle" field (use -1 to ignore)
* - Which to return if several match (use 0 to ignore)
*
* The return value is a pointer to the first matching structure. If no
* structures match the given parameters, NULL is returned.
*/
static const grub_uint8_t *
grub_smbios_match_structure (const grub_int16_t type,
const grub_int32_t handle,
const grub_uint16_t match)
{
const grub_uint8_t *ptr = (const grub_uint8_t *)table_desc.start;
const grub_uint8_t *table_end = (const grub_uint8_t *)table_desc.end;
grub_uint16_t structures = table_desc.structures;
grub_uint16_t structure_count = 0;
grub_uint16_t matches = 0;
while (ptr < table_end
&& ptr[1] >= 4 /* Valid structures include the 4-byte header. */
&& (structure_count++ < structures || structures == 0))
{
grub_uint16_t structure_handle = grub_get_unaligned16 (ptr + 2);
grub_uint8_t structure_type = ptr[0];
if ((handle < 0 || handle == structure_handle)
&& (type < 0 || type == structure_type)
&& (match == 0 || match == ++matches))
return ptr;
else
{
ptr += ptr[1];
while ((*ptr++ != 0 || *ptr++ != 0) && ptr < table_end);
}
if (structure_type == GRUB_SMBIOS_TYPE_END_OF_TABLE)
break;
}
return NULL;
}
static grub_err_t
grub_cmd_smbios (grub_extcmd_context_t ctxt,
int argc __attribute__ ((unused)),
char **argv __attribute__ ((unused)))
{
struct grub_arg_list *state = ctxt->state;
grub_int16_t type = -1;
grub_int32_t handle = -1;
grub_uint16_t match = 0;
grub_uint8_t offset = 0;
const grub_uint8_t *structure;
const char *value;
char *modified_value = NULL;
grub_int32_t option;
grub_int8_t field_type = -1;
grub_uint8_t i;
if (table_desc.start == 0)
return grub_error (GRUB_ERR_IO,
N_("the SMBIOS entry point structure was not found"));
/* Read the given filtering options. */
if (state[0].set)
{
option = grub_strtol (state[0].arg, NULL, 0);
if (option < 0 || option > 255)
return grub_error (GRUB_ERR_BAD_ARGUMENT,
N_("the type must be between 0 and 255"));
type = (grub_int16_t)option;
}
if (state[1].set)
{
option = grub_strtol (state[1].arg, NULL, 0);
if (option < 0 || option > 65535)
return grub_error (GRUB_ERR_BAD_ARGUMENT,
N_("the handle must be between 0 and 65535"));
handle = (grub_int32_t)option;
}
if (state[2].set)
{
option = grub_strtol (state[2].arg, NULL, 0);
if (option <= 0 || option > 65535)
return grub_error (GRUB_ERR_BAD_ARGUMENT,
N_("the match must be a positive integer"));
match = (grub_uint16_t)option;
}
/* Determine the data type of the structure field to retrieve. */
for (i = 0; i < ARRAY_SIZE(field_extractors); i++)
if (state[FIRST_GETTER_OPT + i].set)
{
if (field_type >= 0)
return grub_error (GRUB_ERR_BAD_ARGUMENT,
N_("only one --get option is usable at a time"));
field_type = i;
}
/* Require a choice of a structure field to return. */
if (field_type < 0)
return grub_error (GRUB_ERR_BAD_ARGUMENT,
N_("one of the --get options is required"));
/* Locate a matching SMBIOS structure. */
structure = grub_smbios_match_structure (type, handle, match);
if (structure == NULL)
return grub_error (GRUB_ERR_IO,
N_("no structure matched the given options"));
/* Ensure the requested byte offset is inside the structure. */
option = grub_strtol (state[FIRST_GETTER_OPT + field_type].arg, NULL, 0);
if (option < 0 || option >= structure[1])
return grub_error (GRUB_ERR_OUT_OF_RANGE,
N_("the given offset is outside the structure"));
/* Ensure the requested data type at the offset is inside the structure. */
offset = (grub_uint8_t)option;
if (offset + field_extractors[field_type].field_length > structure[1])
return grub_error (GRUB_ERR_OUT_OF_RANGE,
N_("the field ends outside the structure"));
/* Format the requested structure field into a readable string. */
value = field_extractors[field_type].format (structure, offset);
if (value == NULL)
return grub_error (GRUB_ERR_IO,
N_("failed to retrieve the structure field"));
if (state[LINUX_OPT].set)
value = modified_value = linux_string (value);
/* Store or print the formatted value. */
if (state[SETTER_OPT].set)
grub_env_set (state[SETTER_OPT].arg, value);
else
grub_printf ("%s\n", value);
grub_free(modified_value);
return GRUB_ERR_NONE;
}
GRUB_MOD_INIT(smbios)
{
struct grub_smbios_eps3 *eps3;
struct grub_smbios_eps *eps;
if ((eps3 = grub_smbios_get_eps3 ()))
{
table_desc.start = (grub_addr_t)eps3->table_address;
table_desc.end = table_desc.start + eps3->maximum_table_length;
table_desc.structures = 0; /* SMBIOS3 drops the structure count. */
}
else if ((eps = grub_smbios_get_eps ()))
{
table_desc.start = (grub_addr_t)eps->intermediate.table_address;
table_desc.end = table_desc.start + eps->intermediate.table_length;
table_desc.structures = eps->intermediate.structures;
}
cmd = grub_register_extcmd ("smbios", grub_cmd_smbios, 0,
N_("[-t type] [-h handle] [-m match] "
"(-b|-w|-d|-q|-s|-u) offset "
"[--set variable]"),
N_("Retrieve SMBIOS information."), options);
}
GRUB_MOD_FINI(smbios)
{
grub_unregister_extcmd (cmd);
}
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