src/shared/efi-loader.c

   1 /* SPDX-License-Identifier: LGPL-2.1-or-later */
   2
   3 #include <stdlib.h>
   4 #include <sys/stat.h>
   5 #include <unistd.h>
   6
   7 #include "alloc-util.h"
   8 #include "dirent-util.h"
   9 #include "efi-loader.h"
  10 #include "efivars.h"
  11 #include "fd-util.h"
  12 #include "io-util.h"
  13 #include "parse-util.h"
  14 #include "sort-util.h"
  15 #include "stat-util.h"
  16 #include "stdio-util.h"
  17 #include "string-util.h"
  18 #include "utf8.h"
  19 #include "virt.h"
  20
  21 #if ENABLE_EFI
  22
  23 #define LOAD_OPTION_ACTIVE            0x00000001
  24 #define MEDIA_DEVICE_PATH                   0x04
  25 #define MEDIA_HARDDRIVE_DP                  0x01
  26 #define MEDIA_FILEPATH_DP                   0x04
  27 #define SIGNATURE_TYPE_GUID                 0x02
  28 #define MBR_TYPE_EFI_PARTITION_TABLE_HEADER 0x02
  29 #define END_DEVICE_PATH_TYPE                0x7f
  30 #define END_ENTIRE_DEVICE_PATH_SUBTYPE      0xff
  31 #define EFI_OS_INDICATIONS_BOOT_TO_FW_UI    0x0000000000000001
  32
  33 #define boot_option__contents                   \
  34         {                                       \
  35                 uint32_t attr;                  \
  36                 uint16_t path_len;              \
  37                 uint16_t title[];               \
  38         }
  39
  40 struct boot_option boot_option__contents;
  41 struct boot_option__packed boot_option__contents _packed_;
  42 assert_cc(offsetof(struct boot_option, title) == offsetof(struct boot_option__packed, title));
  43 /* sizeof(struct boot_option) != sizeof(struct boot_option__packed), so
  44  * the *size* of the structure should not be used anywhere below. */
  45
  46 struct drive_path {
  47         uint32_t part_nr;
  48         uint64_t part_start;
  49         uint64_t part_size;
  50         char signature[16];
  51         uint8_t mbr_type;
  52         uint8_t signature_type;
  53 } _packed_;
  54
  55 #define device_path__contents                           \
  56         {                                               \
  57                 uint8_t type;                           \
  58                 uint8_t sub_type;                       \
  59                 uint16_t length;                        \
  60                 union {                                 \
  61                         uint16_t path[0];               \
  62                         struct drive_path drive;        \
  63                 };                                      \
  64         }
  65
  66 struct device_path device_path__contents;
  67 struct device_path__packed device_path__contents _packed_;
  68 assert_cc(sizeof(struct device_path) == sizeof(struct device_path__packed));
  69
  70 int efi_reboot_to_firmware_supported(void) {
  71         _cleanup_free_ void *v = NULL;
  72         static int cache = -1;
  73         uint64_t b;
  74         size_t s;
  75         int r;
  76
  77         if (cache > 0)
  78                 return 0;
  79         if (cache == 0)
  80                 return -EOPNOTSUPP;
  81
  82         if (!is_efi_boot())
  83                 goto not_supported;
  84
  85         r = efi_get_variable(EFI_GLOBAL_VARIABLE(OsIndicationsSupported), NULL, &v, &s);
  86         if (r == -ENOENT)
  87                 goto not_supported; /* variable doesn't exist? it's not supported then */
  88         if (r < 0)
  89                 return r;
  90         if (s != sizeof(uint64_t))
  91                 return -EINVAL;
  92
  93         b = *(uint64_t*) v;
  94         if (!(b & EFI_OS_INDICATIONS_BOOT_TO_FW_UI))
  95                 goto not_supported; /* bit unset? it's not supported then */
  96
  97         cache = 1;
  98         return 0;
  99
 100 not_supported:
 101         cache = 0;
 102         return -EOPNOTSUPP;
 103 }
 104
 105 static int get_os_indications(uint64_t *ret) {
 106         static struct stat cache_stat = {};
 107         _cleanup_free_ void *v = NULL;
 108         static uint64_t cache;
 109         struct stat new_stat;
 110         size_t s;
 111         int r;
 112
 113         assert(ret);
 114
 115         /* Let's verify general support first */
 116         r = efi_reboot_to_firmware_supported();
 117         if (r < 0)
 118                 return r;
 119
 120         /* stat() the EFI variable, to see if the mtime changed. If it did we need to cache again. */
 121         if (stat(EFIVAR_PATH(EFI_GLOBAL_VARIABLE(OsIndications)), &new_stat) < 0) {
 122                 if (errno != ENOENT)
 123                         return -errno;
 124
 125                 /* Doesn't exist? Then we can exit early (also see below) */
 126                 *ret = 0;
 127                 return 0;
 128
 129         } else if (stat_inode_unmodified(&new_stat, &cache_stat)) {
 130                 /* inode didn't change, we can return the cached value */
 131                 *ret = cache;
 132                 return 0;
 133         }
 134
 135         r = efi_get_variable(EFI_GLOBAL_VARIABLE(OsIndications), NULL, &v, &s);
 136         if (r == -ENOENT) {
 137                 /* Some firmware implementations that do support OsIndications and report that with
 138                  * OsIndicationsSupported will remove the OsIndications variable when it is unset. Let's
 139                  * pretend it's 0 then, to hide this implementation detail. Note that this call will return
 140                  * -ENOENT then only if the support for OsIndications is missing entirely, as determined by
 141                  * efi_reboot_to_firmware_supported() above. */
 142                 *ret = 0;
 143                 return 0;
 144         }
 145         if (r < 0)
 146                 return r;
 147         if (s != sizeof(uint64_t))
 148                 return -EINVAL;
 149
 150         cache_stat = new_stat;
 151         *ret = cache = *(uint64_t *)v;
 152         return 0;
 153 }
 154
 155 int efi_get_reboot_to_firmware(void) {
 156         int r;
 157         uint64_t b;
 158
 159         r = get_os_indications(&b);
 160         if (r < 0)
 161                 return r;
 162
 163         return !!(b & EFI_OS_INDICATIONS_BOOT_TO_FW_UI);
 164 }
 165
 166 int efi_set_reboot_to_firmware(bool value) {
 167         int r;
 168         uint64_t b, b_new;
 169
 170         r = get_os_indications(&b);
 171         if (r < 0)
 172                 return r;
 173
 174         b_new = UPDATE_FLAG(b, EFI_OS_INDICATIONS_BOOT_TO_FW_UI, value);
 175
 176         /* Avoid writing to efi vars store if we can due to firmware bugs. */
 177         if (b != b_new)
 178                 return efi_set_variable(EFI_GLOBAL_VARIABLE(OsIndications), &b_new, sizeof(uint64_t));
 179
 180         return 0;
 181 }
 182
 183 static ssize_t utf16_size(const uint16_t *s, size_t buf_len_bytes) {
 184         size_t l = 0;
 185
 186         /* Returns the size of the string in bytes without the terminating two zero bytes */
 187
 188         if (buf_len_bytes % sizeof(uint16_t) != 0)
 189                 return -EINVAL;
 190
 191         while (l < buf_len_bytes / sizeof(uint16_t)) {
 192                 if (s[l] == 0)
 193                         return (l + 1) * sizeof(uint16_t);
 194                 l++;
 195         }
 196
 197         return -EINVAL; /* The terminator was not found */
 198 }
 199
 200 struct guid {
 201         uint32_t u1;
 202         uint16_t u2;
 203         uint16_t u3;
 204         uint8_t u4[8];
 205 } _packed_;
 206
 207 static void efi_guid_to_id128(const void *guid, sd_id128_t *id128) {
 208         uint32_t u1;
 209         uint16_t u2, u3;
 210         const struct guid *uuid = guid;
 211
 212         memcpy(&u1, &uuid->u1, sizeof(uint32_t));
 213         id128->bytes[0] = (u1 >> 24) & 0xff;
 214         id128->bytes[1] = (u1 >> 16) & 0xff;
 215         id128->bytes[2] = (u1 >> 8) & 0xff;
 216         id128->bytes[3] = u1 & 0xff;
 217         memcpy(&u2, &uuid->u2, sizeof(uint16_t));
 218         id128->bytes[4] = (u2 >> 8) & 0xff;
 219         id128->bytes[5] = u2 & 0xff;
 220         memcpy(&u3, &uuid->u3, sizeof(uint16_t));
 221         id128->bytes[6] = (u3 >> 8) & 0xff;
 222         id128->bytes[7] = u3 & 0xff;
 223         memcpy(&id128->bytes[8], uuid->u4, sizeof(uuid->u4));
 224 }
 225
 226 int efi_get_boot_option(
 227                 uint16_t id,
 228                 char **title,
 229                 sd_id128_t *part_uuid,
 230                 char **path,
 231                 bool *active) {
 232
 233         char variable[STRLEN(EFI_GLOBAL_VARIABLE_STR("Boot")) + 4 + 1];
 234         _cleanup_free_ uint8_t *buf = NULL;
 235         size_t l;
 236         struct boot_option *header;
 237         ssize_t title_size;
 238         _cleanup_free_ char *s = NULL, *p = NULL;
 239         sd_id128_t p_uuid = SD_ID128_NULL;
 240         int r;
 241
 242         if (!is_efi_boot())
 243                 return -EOPNOTSUPP;
 244
 245         xsprintf(variable, EFI_GLOBAL_VARIABLE_STR("Boot%04X"), id);
 246         r = efi_get_variable(variable, NULL, (void **)&buf, &l);
 247         if (r < 0)
 248                 return r;
 249         if (l < offsetof(struct boot_option, title))
 250                 return -ENOENT;
 251
 252         header = (struct boot_option *)buf;
 253         title_size = utf16_size(header->title, l - offsetof(struct boot_option, title));
 254         if (title_size < 0)
 255                 return title_size;
 256
 257         if (title) {
 258                 s = utf16_to_utf8(header->title, title_size);
 259                 if (!s)
 260                         return -ENOMEM;
 261         }
 262
 263         if (header->path_len > 0) {
 264                 uint8_t *dbuf;
 265                 size_t dnext, doff;
 266
 267                 doff = offsetof(struct boot_option, title) + title_size;
 268                 dbuf = buf + doff;
 269                 if (header->path_len > l - doff)
 270                         return -EINVAL;
 271
 272                 dnext = 0;
 273                 while (dnext < header->path_len) {
 274                         struct device_path *dpath;
 275
 276                         dpath = (struct device_path *)(dbuf + dnext);
 277                         if (dpath->length < 4)
 278                                 break;
 279
 280                         /* Type 0x7F – End of Hardware Device Path, Sub-Type 0xFF – End Entire Device Path */
 281                         if (dpath->type == END_DEVICE_PATH_TYPE && dpath->sub_type == END_ENTIRE_DEVICE_PATH_SUBTYPE)
 282                                 break;
 283
 284                         dnext += dpath->length;
 285
 286                         /* Type 0x04 – Media Device Path */
 287                         if (dpath->type != MEDIA_DEVICE_PATH)
 288                                 continue;
 289
 290                         /* Sub-Type 1 – Hard Drive */
 291                         if (dpath->sub_type == MEDIA_HARDDRIVE_DP) {
 292                                 /* 0x02 – GUID Partition Table */
 293                                 if (dpath->drive.mbr_type != MBR_TYPE_EFI_PARTITION_TABLE_HEADER)
 294                                         continue;
 295
 296                                 /* 0x02 – GUID signature */
 297                                 if (dpath->drive.signature_type != SIGNATURE_TYPE_GUID)
 298                                         continue;
 299
 300                                 if (part_uuid)
 301                                         efi_guid_to_id128(dpath->drive.signature, &p_uuid);
 302                                 continue;
 303                         }
 304
 305                         /* Sub-Type 4 – File Path */
 306                         if (dpath->sub_type == MEDIA_FILEPATH_DP && !p && path) {
 307                                 p = utf16_to_utf8(dpath->path, dpath->length-4);
 308                                 if (!p)
 309                                         return  -ENOMEM;
 310
 311                                 efi_tilt_backslashes(p);
 312                                 continue;
 313                         }
 314                 }
 315         }
 316
 317         if (title)
 318                 *title = TAKE_PTR(s);
 319         if (part_uuid)
 320                 *part_uuid = p_uuid;
 321         if (path)
 322                 *path = TAKE_PTR(p);
 323         if (active)
 324                 *active = header->attr & LOAD_OPTION_ACTIVE;
 325
 326         return 0;
 327 }
 328
 329 static void to_utf16(uint16_t *dest, const char *src) {
 330         int i;
 331
 332         for (i = 0; src[i] != '\0'; i++)
 333                 dest[i] = src[i];
 334         dest[i] = '\0';
 335 }
 336
 337 static void id128_to_efi_guid(sd_id128_t id, void *guid) {
 338         struct guid uuid = {
 339                 .u1 = id.bytes[0] << 24 | id.bytes[1] << 16 | id.bytes[2] << 8 | id.bytes[3],
 340                 .u2 = id.bytes[4] << 8 | id.bytes[5],
 341                 .u3 = id.bytes[6] << 8 | id.bytes[7],
 342         };
 343         memcpy(uuid.u4, id.bytes+8, sizeof(uuid.u4));
 344         memcpy(guid, &uuid, sizeof(uuid));
 345 }
 346
 347 static uint16_t *tilt_slashes(uint16_t *s) {
 348         for (uint16_t *p = s; *p; p++)
 349                 if (*p == '/')
 350                         *p = '\\';
 351
 352         return s;
 353 }
 354
 355 int efi_add_boot_option(
 356                 uint16_t id,
 357                 const char *title,
 358                 uint32_t part,
 359                 uint64_t pstart,
 360                 uint64_t psize,
 361                 sd_id128_t part_uuid,
 362                 const char *path) {
 363
 364         size_t size, title_len, path_len;
 365         _cleanup_free_ char *buf = NULL;
 366         struct boot_option *option;
 367         struct device_path *devicep;
 368         char variable[STRLEN(EFI_GLOBAL_VARIABLE_STR("Boot")) + 4 + 1];
 369
 370         if (!is_efi_boot())
 371                 return -EOPNOTSUPP;
 372
 373         title_len = (strlen(title)+1) * 2;
 374         path_len = (strlen(path)+1) * 2;
 375
 376         buf = malloc0(offsetof(struct boot_option, title) + title_len +
 377                       sizeof(struct drive_path) +
 378                       sizeof(struct device_path) + path_len);
 379         if (!buf)
 380                 return -ENOMEM;
 381
 382         /* header */
 383         option = (struct boot_option *)buf;
 384         option->attr = LOAD_OPTION_ACTIVE;
 385         option->path_len = offsetof(struct device_path, drive) + sizeof(struct drive_path) +
 386                            offsetof(struct device_path, path) + path_len +
 387                            offsetof(struct device_path, path);
 388         to_utf16(option->title, title);
 389         size = offsetof(struct boot_option, title) + title_len;
 390
 391         /* partition info */
 392         devicep = (struct device_path *)(buf + size);
 393         devicep->type = MEDIA_DEVICE_PATH;
 394         devicep->sub_type = MEDIA_HARDDRIVE_DP;
 395         devicep->length = offsetof(struct device_path, drive) + sizeof(struct drive_path);
 396         memcpy(&devicep->drive.part_nr, &part, sizeof(uint32_t));
 397         memcpy(&devicep->drive.part_start, &pstart, sizeof(uint64_t));
 398         memcpy(&devicep->drive.part_size, &psize, sizeof(uint64_t));
 399         id128_to_efi_guid(part_uuid, devicep->drive.signature);
 400         devicep->drive.mbr_type = MBR_TYPE_EFI_PARTITION_TABLE_HEADER;
 401         devicep->drive.signature_type = SIGNATURE_TYPE_GUID;
 402         size += devicep->length;
 403
 404         /* path to loader */
 405         devicep = (struct device_path *)(buf + size);
 406         devicep->type = MEDIA_DEVICE_PATH;
 407         devicep->sub_type = MEDIA_FILEPATH_DP;
 408         devicep->length = offsetof(struct device_path, path) + path_len;
 409         to_utf16(devicep->path, path);
 410         tilt_slashes(devicep->path);
 411         size += devicep->length;
 412
 413         /* end of path */
 414         devicep = (struct device_path *)(buf + size);
 415         devicep->type = END_DEVICE_PATH_TYPE;
 416         devicep->sub_type = END_ENTIRE_DEVICE_PATH_SUBTYPE;
 417         devicep->length = offsetof(struct device_path, path);
 418         size += devicep->length;
 419
 420         xsprintf(variable, EFI_GLOBAL_VARIABLE_STR("Boot%04X"), id);
 421         return efi_set_variable(variable, buf, size);
 422 }
 423
 424 int efi_remove_boot_option(uint16_t id) {
 425         char variable[STRLEN(EFI_GLOBAL_VARIABLE_STR("Boot")) + 4 + 1];
 426
 427         if (!is_efi_boot())
 428                 return -EOPNOTSUPP;
 429
 430         xsprintf(variable, EFI_GLOBAL_VARIABLE_STR("Boot%04X"), id);
 431         return efi_set_variable(variable, NULL, 0);
 432 }
 433
 434 int efi_get_boot_order(uint16_t **order) {
 435         _cleanup_free_ void *buf = NULL;
 436         size_t l;
 437         int r;
 438
 439         if (!is_efi_boot())
 440                 return -EOPNOTSUPP;
 441
 442         r = efi_get_variable(EFI_GLOBAL_VARIABLE(BootOrder), NULL, &buf, &l);
 443         if (r < 0)
 444                 return r;
 445
 446         if (l <= 0)
 447                 return -ENOENT;
 448
 449         if (l % sizeof(uint16_t) > 0 ||
 450             l / sizeof(uint16_t) > INT_MAX)
 451                 return -EINVAL;
 452
 453         *order = TAKE_PTR(buf);
 454         return (int) (l / sizeof(uint16_t));
 455 }
 456
 457 int efi_set_boot_order(uint16_t *order, size_t n) {
 458
 459         if (!is_efi_boot())
 460                 return -EOPNOTSUPP;
 461
 462         return efi_set_variable(EFI_GLOBAL_VARIABLE(BootOrder), order, n * sizeof(uint16_t));
 463 }
 464
 465 static int boot_id_hex(const char s[static 4]) {
 466         int id = 0;
 467
 468         assert(s);
 469
 470         for (int i = 0; i < 4; i++)
 471                 if (s[i] >= '0' && s[i] <= '9')
 472                         id |= (s[i] - '0') << (3 - i) * 4;
 473                 else if (s[i] >= 'A' && s[i] <= 'F')
 474                         id |= (s[i] - 'A' + 10) << (3 - i) * 4;
 475                 else
 476                         return -EINVAL;
 477
 478         return id;
 479 }
 480
 481 static int cmp_uint16(const uint16_t *a, const uint16_t *b) {
 482         return CMP(*a, *b);
 483 }
 484
 485 int efi_get_boot_options(uint16_t **options) {
 486         _cleanup_closedir_ DIR *dir = NULL;
 487         _cleanup_free_ uint16_t *list = NULL;
 488         int count = 0;
 489
 490         assert(options);
 491
 492         if (!is_efi_boot())
 493                 return -EOPNOTSUPP;
 494
 495         dir = opendir(EFIVAR_PATH("."));
 496         if (!dir)
 497                 return -errno;
 498
 499         FOREACH_DIRENT(de, dir, return -errno) {
 500                 int id;
 501
 502                 if (strncmp(de->d_name, "Boot", 4) != 0)
 503                         continue;
 504
 505                 if (strlen(de->d_name) != 45)
 506                         continue;
 507
 508                 if (strcmp(de->d_name + 8, EFI_GLOBAL_VARIABLE_STR("")) != 0)  /* generate variable suffix using macro */
 509                         continue;
 510
 511                 id = boot_id_hex(de->d_name + 4);
 512                 if (id < 0)
 513                         continue;
 514
 515                 if (!GREEDY_REALLOC(list, count + 1))
 516                         return -ENOMEM;
 517
 518                 list[count++] = id;
 519         }
 520
 521         typesafe_qsort(list, count, cmp_uint16);
 522
 523         *options = TAKE_PTR(list);
 524
 525         return count;
 526 }
 527
 528 static int read_usec(const char *variable, usec_t *u) {
 529         _cleanup_free_ char *j = NULL;
 530         int r;
 531         uint64_t x = 0;
 532
 533         assert(variable);
 534         assert(u);
 535
 536         r = efi_get_variable_string(variable, &j);
 537         if (r < 0)
 538                 return r;
 539
 540         r = safe_atou64(j, &x);
 541         if (r < 0)
 542                 return r;
 543
 544         *u = x;
 545         return 0;
 546 }
 547
 548 int efi_loader_get_boot_usec(usec_t *firmware, usec_t *loader) {
 549         uint64_t x, y;
 550         int r;
 551
 552         assert(firmware);
 553         assert(loader);
 554
 555         if (!is_efi_boot())
 556                 return -EOPNOTSUPP;
 557
 558         r = read_usec(EFI_LOADER_VARIABLE(LoaderTimeInitUSec), &x);
 559         if (r < 0)
 560                 return log_debug_errno(r, "Failed to read LoaderTimeInitUSec: %m");
 561
 562         r = read_usec(EFI_LOADER_VARIABLE(LoaderTimeExecUSec), &y);
 563         if (r < 0)
 564                 return log_debug_errno(r, "Failed to read LoaderTimeExecUSec: %m");
 565
 566         if (y == 0 || y < x || y - x > USEC_PER_HOUR)
 567                 return log_debug_errno(SYNTHETIC_ERRNO(EIO),
 568                                        "Bad LoaderTimeInitUSec=%"PRIu64", LoaderTimeExecUSec=%" PRIu64"; refusing.",
 569                                        x, y);
 570
 571         *firmware = x;
 572         *loader = y;
 573
 574         return 0;
 575 }
 576
 577 int efi_loader_get_device_part_uuid(sd_id128_t *u) {
 578         _cleanup_free_ char *p = NULL;
 579         int r, parsed[16];
 580
 581         if (!is_efi_boot())
 582                 return -EOPNOTSUPP;
 583
 584         r = efi_get_variable_string(EFI_LOADER_VARIABLE(LoaderDevicePartUUID), &p);
 585         if (r < 0)
 586                 return r;
 587
 588         if (sscanf(p, SD_ID128_UUID_FORMAT_STR,
 589                    &parsed[0], &parsed[1], &parsed[2], &parsed[3],
 590                    &parsed[4], &parsed[5], &parsed[6], &parsed[7],
 591                    &parsed[8], &parsed[9], &parsed[10], &parsed[11],
 592                    &parsed[12], &parsed[13], &parsed[14], &parsed[15]) != 16)
 593                 return -EIO;
 594
 595         if (u)
 596                 for (unsigned i = 0; i < ELEMENTSOF(parsed); i++)
 597                         u->bytes[i] = parsed[i];
 598
 599         return 0;
 600 }
 601
 602 int efi_loader_get_entries(char ***ret) {
 603         _cleanup_free_ char16_t *entries = NULL;
 604         _cleanup_strv_free_ char **l = NULL;
 605         size_t size;
 606         int r;
 607
 608         assert(ret);
 609
 610         if (!is_efi_boot())
 611                 return -EOPNOTSUPP;
 612
 613         r = efi_get_variable(EFI_LOADER_VARIABLE(LoaderEntries), NULL, (void**) &entries, &size);
 614         if (r < 0)
 615                 return r;
 616
 617         /* The variable contains a series of individually NUL terminated UTF-16 strings. */
 618
 619         for (size_t i = 0, start = 0;; i++) {
 620                 _cleanup_free_ char *decoded = NULL;
 621                 bool end;
 622
 623                 /* Is this the end of the variable's data? */
 624                 end = i * sizeof(char16_t) >= size;
 625
 626                 /* Are we in the middle of a string? (i.e. not at the end of the variable, nor at a NUL terminator?) If
 627                  * so, let's go to the next entry. */
 628                 if (!end && entries[i] != 0)
 629                         continue;
 630
 631                 /* We reached the end of a string, let's decode it into UTF-8 */
 632                 decoded = utf16_to_utf8(entries + start, (i - start) * sizeof(char16_t));
 633                 if (!decoded)
 634                         return -ENOMEM;
 635
 636                 if (efi_loader_entry_name_valid(decoded)) {
 637                         r = strv_consume(&l, TAKE_PTR(decoded));
 638                         if (r < 0)
 639                                 return r;
 640                 } else
 641                         log_debug("Ignoring invalid loader entry '%s'.", decoded);
 642
 643                 /* We reached the end of the variable */
 644                 if (end)
 645                         break;
 646
 647                 /* Continue after the NUL byte */
 648                 start = i + 1;
 649         }
 650
 651         *ret = TAKE_PTR(l);
 652         return 0;
 653 }
 654
 655 int efi_loader_get_features(uint64_t *ret) {
 656         _cleanup_free_ void *v = NULL;
 657         size_t s;
 658         int r;
 659
 660         if (!is_efi_boot()) {
 661                 *ret = 0;
 662                 return 0;
 663         }
 664
 665         r = efi_get_variable(EFI_LOADER_VARIABLE(LoaderFeatures), NULL, &v, &s);
 666         if (r == -ENOENT) {
 667                 _cleanup_free_ char *info = NULL;
 668
 669                 /* The new (v240+) LoaderFeatures variable is not supported, let's see if it's systemd-boot at all */
 670                 r = efi_get_variable_string(EFI_LOADER_VARIABLE(LoaderInfo), &info);
 671                 if (r < 0) {
 672                         if (r != -ENOENT)
 673                                 return r;
 674
 675                         /* Variable not set, definitely means not systemd-boot */
 676
 677                 } else if (first_word(info, "systemd-boot")) {
 678
 679                         /* An older systemd-boot version. Let's hardcode the feature set, since it was pretty
 680                          * static in all its versions. */
 681
 682                         *ret = EFI_LOADER_FEATURE_CONFIG_TIMEOUT |
 683                                 EFI_LOADER_FEATURE_ENTRY_DEFAULT |
 684                                 EFI_LOADER_FEATURE_ENTRY_ONESHOT;
 685
 686                         return 0;
 687                 }
 688
 689                 /* No features supported */
 690                 *ret = 0;
 691                 return 0;
 692         }
 693         if (r < 0)
 694                 return r;
 695
 696         if (s != sizeof(uint64_t))
 697                 return log_debug_errno(SYNTHETIC_ERRNO(EINVAL),
 698                                        "LoaderFeatures EFI variable doesn't have the right size.");
 699
 700         memcpy(ret, v, sizeof(uint64_t));
 701         return 0;
 702 }
 703
 704 int efi_loader_get_config_timeout_one_shot(usec_t *ret) {
 705         _cleanup_free_ char *v = NULL;
 706         static struct stat cache_stat = {};
 707         struct stat new_stat;
 708         static usec_t cache;
 709         uint64_t sec;
 710         int r;
 711
 712         assert(ret);
 713
 714         /* stat() the EFI variable, to see if the mtime changed. If it did, we need to cache again. */
 715         if (stat(EFIVAR_PATH(EFI_LOADER_VARIABLE(LoaderConfigTimeoutOneShot)), &new_stat) < 0)
 716                 return -errno;
 717
 718         if (stat_inode_unmodified(&new_stat, &cache_stat)) {
 719                 *ret = cache;
 720                 return 0;
 721         }
 722
 723         r = efi_get_variable_string(EFI_LOADER_VARIABLE(LoaderConfigTimeoutOneShot), &v);
 724         if (r < 0)
 725                 return r;
 726
 727         r = safe_atou64(v, &sec);
 728         if (r < 0)
 729                 return r;
 730         if (sec > USEC_INFINITY / USEC_PER_SEC)
 731                 return -ERANGE;
 732
 733         cache_stat = new_stat;
 734         *ret = cache = sec * USEC_PER_SEC; /* return in µs */
 735         return 0;
 736 }
 737
 738 int efi_loader_update_entry_one_shot_cache(char **cache, struct stat *cache_stat) {
 739         _cleanup_free_ char *v = NULL;
 740         struct stat new_stat;
 741         int r;
 742
 743         assert(cache);
 744         assert(cache_stat);
 745
 746         /* stat() the EFI variable, to see if the mtime changed. If it did we need to cache again. */
 747         if (stat(EFIVAR_PATH(EFI_LOADER_VARIABLE(LoaderEntryOneShot)), &new_stat) < 0)
 748                 return -errno;
 749
 750         if (stat_inode_unmodified(&new_stat, cache_stat))
 751                 return 0;
 752
 753         r = efi_get_variable_string(EFI_LOADER_VARIABLE(LoaderEntryOneShot), &v);
 754         if (r < 0)
 755                 return r;
 756
 757         if (!efi_loader_entry_name_valid(v))
 758                 return -EINVAL;
 759
 760         *cache_stat = new_stat;
 761         free_and_replace(*cache, v);
 762
 763         return 0;
 764 }
 765
 766 bool efi_has_tpm2(void) {
 767         static int cache = -1;
 768
 769         /* Returns whether the system has a TPM2 chip which is known to the EFI firmware. */
 770
 771         if (cache < 0) {
 772
 773                 /* First, check if we are on an EFI boot at all. */
 774                 if (!is_efi_boot())
 775                         cache = false;
 776                 else {
 777                         /* Then, check if the ACPI table "TPM2" exists, which is the TPM2 event log table, see:
 778                          * https://trustedcomputinggroup.org/wp-content/uploads/TCG_ACPIGeneralSpecification_v1.20_r8.pdf
 779                          * This table exists whenever the firmware is hooked up to TPM2. */
 780                         cache = access("/sys/firmware/acpi/tables/TPM2", F_OK) >= 0;
 781                         if (!cache && errno != ENOENT)
 782                                 log_debug_errno(errno, "Unable to test whether /sys/firmware/acpi/tables/TPM2 exists, assuming it doesn't: %m");
 783                 }
 784         }
 785
 786         return cache;
 787 }
 788
 789 #endif
 790
 791 bool efi_loader_entry_name_valid(const char *s) {
 792         if (!filename_is_valid(s)) /* Make sure entry names fit in filenames */
 793                 return false;
 794
 795         return in_charset(s, ALPHANUMERICAL "+-_.");
 796 }
 797
 798 char *efi_tilt_backslashes(char *s) {
 799         for (char *p = s; *p; p++)
 800                 if (*p == '\\')
 801                         *p = '/';
 802
 803         return s;
 804 }