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