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systemd/src/shared/efivars.c
Lennart Poettering 7e8185ef94 fix a couple of more lazy "return -1"
Fix should strictly follow the rule to return negative errno-style
error codes from functions, hence let's fix more "return -1"-style
lazinesses.
2014-08-11 18:35:54 +02:00

466 lines
12 KiB
C
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/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/
/***
This file is part of systemd.
Copyright 2013 Lennart Poettering
systemd is free software; you can redistribute it and/or modify it
under the terms of the GNU Lesser General Public License as published by
the Free Software Foundation; either version 2.1 of the License, or
(at your option) any later version.
systemd 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public License
along with systemd; If not, see <http://www.gnu.org/licenses/>.
***/
#include <unistd.h>
#include <string.h>
#include <fcntl.h>
#include <ctype.h>
#include "acpi-fpdt.h"
#include "util.h"
#include "utf8.h"
#include "efivars.h"
#ifdef ENABLE_EFI
bool is_efi_boot(void) {
return access("/sys/firmware/efi", F_OK) >= 0;
}
static int read_flag(const char *varname) {
int r;
_cleanup_free_ void *v = NULL;
size_t s;
uint8_t b;
r = efi_get_variable(EFI_VENDOR_GLOBAL, varname, NULL, &v, &s);
if (r < 0)
return r;
if (s != 1)
return -EINVAL;
b = *(uint8_t *)v;
r = b > 0;
return r;
}
int is_efi_secure_boot(void) {
return read_flag("SecureBoot");
}
int is_efi_secure_boot_setup_mode(void) {
return read_flag("SetupMode");
}
int efi_get_variable(
sd_id128_t vendor,
const char *name,
uint32_t *attribute,
void **value,
size_t *size) {
_cleanup_close_ int fd = -1;
_cleanup_free_ char *p = NULL;
uint32_t a;
ssize_t n;
struct stat st;
void *r;
assert(name);
assert(value);
assert(size);
if (asprintf(&p,
"/sys/firmware/efi/efivars/%s-%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
name, SD_ID128_FORMAT_VAL(vendor)) < 0)
return -ENOMEM;
fd = open(p, O_RDONLY|O_NOCTTY|O_CLOEXEC);
if (fd < 0)
return -errno;
if (fstat(fd, &st) < 0)
return -errno;
if (st.st_size < 4)
return -EIO;
if (st.st_size > 4*1024*1024 + 4)
return -E2BIG;
n = read(fd, &a, sizeof(a));
if (n < 0)
return -errno;
if (n != sizeof(a))
return -EIO;
r = malloc(st.st_size - 4 + 2);
if (!r)
return -ENOMEM;
n = read(fd, r, (size_t) st.st_size - 4);
if (n < 0) {
free(r);
return -errno;
}
if (n != (ssize_t) st.st_size - 4) {
free(r);
return -EIO;
}
/* Always NUL terminate (2 bytes, to protect UTF-16) */
((char*) r)[st.st_size - 4] = 0;
((char*) r)[st.st_size - 4 + 1] = 0;
*value = r;
*size = (size_t) st.st_size - 4;
if (attribute)
*attribute = a;
return 0;
}
int efi_get_variable_string(sd_id128_t vendor, const char *name, char **p) {
_cleanup_free_ void *s = NULL;
size_t ss = 0;
int r;
char *x;
r = efi_get_variable(vendor, name, NULL, &s, &ss);
if (r < 0)
return r;
x = utf16_to_utf8(s, ss);
if (!x)
return -ENOMEM;
*p = x;
return 0;
}
static size_t utf16_size(const uint16_t *s) {
size_t l = 0;
while (s[l] > 0)
l++;
return (l+1) * sizeof(uint16_t);
}
static void efi_guid_to_id128(const void *guid, sd_id128_t *id128) {
struct uuid {
uint32_t u1;
uint16_t u2;
uint16_t u3;
uint8_t u4[8];
} _packed_;
const struct uuid *uuid = guid;
id128->bytes[0] = (uuid->u1 >> 24) & 0xff;
id128->bytes[1] = (uuid->u1 >> 16) & 0xff;
id128->bytes[2] = (uuid->u1 >> 8) & 0xff;
id128->bytes[3] = (uuid->u1) & 0xff;
id128->bytes[4] = (uuid->u2 >> 8) & 0xff;
id128->bytes[5] = (uuid->u2) & 0xff;
id128->bytes[6] = (uuid->u3 >> 8) & 0xff;
id128->bytes[7] = (uuid->u3) & 0xff;
memcpy(&id128->bytes[8], uuid->u4, sizeof(uuid->u4));
}
int efi_get_boot_option(
uint16_t id,
char **title,
sd_id128_t *part_uuid,
char **path) {
struct boot_option {
uint32_t attr;
uint16_t path_len;
uint16_t title[];
} _packed_;
struct drive_path {
uint32_t part_nr;
uint64_t part_start;
uint64_t part_size;
char signature[16];
uint8_t mbr_type;
uint8_t signature_type;
} _packed_;
struct device_path {
uint8_t type;
uint8_t sub_type;
uint16_t length;
union {
uint16_t path[0];
struct drive_path drive;
};
} _packed_;
char boot_id[9];
_cleanup_free_ uint8_t *buf = NULL;
size_t l;
struct boot_option *header;
size_t title_size;
char *s = NULL;
char *p = NULL;
sd_id128_t p_uuid = SD_ID128_NULL;
int err;
snprintf(boot_id, sizeof(boot_id), "Boot%04X", id);
err = efi_get_variable(EFI_VENDOR_GLOBAL, boot_id, NULL, (void **)&buf, &l);
if (err < 0)
return err;
if (l < sizeof(struct boot_option))
return -ENOENT;
header = (struct boot_option *)buf;
title_size = utf16_size(header->title);
if (title_size > l - offsetof(struct boot_option, title))
return -EINVAL;
if (title) {
s = utf16_to_utf8(header->title, title_size);
if (!s) {
err = -ENOMEM;
goto err;
}
}
if (header->path_len > 0) {
uint8_t *dbuf;
size_t dnext;
dbuf = buf + offsetof(struct boot_option, title) + title_size;
dnext = 0;
while (dnext < header->path_len) {
struct device_path *dpath;
dpath = (struct device_path *)(dbuf + dnext);
if (dpath->length < 4)
break;
/* Type 0x7F End of Hardware Device Path, Sub-Type 0xFF End Entire Device Path */
if (dpath->type == 0x7f && dpath->sub_type == 0xff)
break;
dnext += dpath->length;
/* Type 0x04 Media Device Path */
if (dpath->type != 0x04)
continue;
/* Sub-Type 1 Hard Drive */
if (dpath->sub_type == 0x01) {
/* 0x02 GUID Partition Table */
if (dpath->drive.mbr_type != 0x02)
continue;
/* 0x02 GUID signature */
if (dpath->drive.signature_type != 0x02)
continue;
if (part_uuid)
efi_guid_to_id128(dpath->drive.signature, &p_uuid);
continue;
}
/* Sub-Type 4 File Path */
if (dpath->sub_type == 0x04 && !p && path) {
p = utf16_to_utf8(dpath->path, dpath->length-4);
continue;
}
}
}
if (title)
*title = s;
if (part_uuid)
*part_uuid = p_uuid;
if (path)
*path = p;
return 0;
err:
free(s);
free(p);
return err;
}
int efi_get_boot_order(uint16_t **order) {
void *buf;
size_t l;
int r;
r = efi_get_variable(EFI_VENDOR_GLOBAL, "BootOrder", NULL, &buf, &l);
if (r < 0)
return r;
if (l <= 0) {
free(buf);
return -ENOENT;
}
if ((l % sizeof(uint16_t) > 0) ||
(l / sizeof(uint16_t) > INT_MAX)) {
free(buf);
return -EINVAL;
}
*order = buf;
return (int) (l / sizeof(uint16_t));
}
static int boot_id_hex(const char s[4]) {
int i;
int id = 0;
for (i = 0; i < 4; i++)
if (s[i] >= '0' && s[i] <= '9')
id |= (s[i] - '0') << (3 - i) * 4;
else if (s[i] >= 'A' && s[i] <= 'F')
id |= (s[i] - 'A' + 10) << (3 - i) * 4;
else
return -EINVAL;
return id;
}
static int cmp_uint16(const void *_a, const void *_b) {
const uint16_t *a = _a, *b = _b;
return (int)*a - (int)*b;
}
int efi_get_boot_options(uint16_t **options) {
_cleanup_closedir_ DIR *dir = NULL;
struct dirent *de;
uint16_t *list = NULL;
int count = 0, r;
assert(options);
dir = opendir("/sys/firmware/efi/efivars/");
if (!dir)
return -errno;
FOREACH_DIRENT(de, dir, r = -errno; goto fail) {
int id;
uint16_t *t;
if (strncmp(de->d_name, "Boot", 4) != 0)
continue;
if (strlen(de->d_name) != 45)
continue;
if (strcmp(de->d_name + 8, "-8be4df61-93ca-11d2-aa0d-00e098032b8c") != 0)
continue;
id = boot_id_hex(de->d_name + 4);
if (id < 0)
continue;
t = realloc(list, (count + 1) * sizeof(uint16_t));
if (!t) {
r = -ENOMEM;
goto fail;
}
list = t;
list[count ++] = id;
}
qsort_safe(list, count, sizeof(uint16_t), cmp_uint16);
*options = list;
return count;
fail:
free(list);
return r;
}
static int read_usec(sd_id128_t vendor, const char *name, usec_t *u) {
_cleanup_free_ char *j = NULL;
int r;
uint64_t x = 0;
assert(name);
assert(u);
r = efi_get_variable_string(EFI_VENDOR_LOADER, name, &j);
if (r < 0)
return r;
r = safe_atou64(j, &x);
if (r < 0)
return r;
*u = x;
return 0;
}
int efi_loader_get_boot_usec(usec_t *firmware, usec_t *loader) {
uint64_t x, y;
int r;
assert(firmware);
assert(loader);
r = read_usec(EFI_VENDOR_LOADER, "LoaderTimeInitUSec", &x);
if (r < 0)
return r;
r = read_usec(EFI_VENDOR_LOADER, "LoaderTimeExecUSec", &y);
if (r < 0)
return r;
if (y == 0 || y < x)
return -EIO;
if (y > USEC_PER_HOUR)
return -EIO;
*firmware = x;
*loader = y;
return 0;
}
int efi_loader_get_device_part_uuid(sd_id128_t *u) {
_cleanup_free_ char *p = NULL;
int r, parsed[16];
r = efi_get_variable_string(EFI_VENDOR_LOADER, "LoaderDevicePartUUID", &p);
if (r < 0)
return r;
if (sscanf(p, "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
&parsed[0], &parsed[1], &parsed[2], &parsed[3],
&parsed[4], &parsed[5], &parsed[6], &parsed[7],
&parsed[8], &parsed[9], &parsed[10], &parsed[11],
&parsed[12], &parsed[13], &parsed[14], &parsed[15]) != 16)
return -EIO;
if (u) {
unsigned i;
for (i = 0; i < ELEMENTSOF(parsed); i++)
u->bytes[i] = parsed[i];
}
return 0;
}
#endif