src/shared/efivars.c

   1 /* SPDX-License-Identifier: LGPL-2.1+ */
   2 /***
   3   Copyright 2013 Lennart Poettering
   4 ***/
   5
   6 #include <dirent.h>
   7 #include <errno.h>
   8 #include <fcntl.h>
   9 #include <limits.h>
  10 #include <stdio.h>
  11 #include <stdlib.h>
  12 #include <string.h>
  13 #include <sys/stat.h>
  14 #include <unistd.h>
  15
  16 #include "sd-id128.h"
  17
  18 #include "alloc-util.h"
  19 #include "dirent-util.h"
  20 #include "efivars.h"
  21 #include "fd-util.h"
  22 #include "io-util.h"
  23 #include "macro.h"
  24 #include "parse-util.h"
  25 #include "stdio-util.h"
  26 #include "time-util.h"
  27 #include "utf8.h"
  28 #include "util.h"
  29 #include "virt.h"
  30
  31 #if ENABLE_EFI
  32
  33 #define LOAD_OPTION_ACTIVE            0x00000001
  34 #define MEDIA_DEVICE_PATH                   0x04
  35 #define MEDIA_HARDDRIVE_DP                  0x01
  36 #define MEDIA_FILEPATH_DP                   0x04
  37 #define SIGNATURE_TYPE_GUID                 0x02
  38 #define MBR_TYPE_EFI_PARTITION_TABLE_HEADER 0x02
  39 #define END_DEVICE_PATH_TYPE                0x7f
  40 #define END_ENTIRE_DEVICE_PATH_SUBTYPE      0xff
  41 #define EFI_OS_INDICATIONS_BOOT_TO_FW_UI    0x0000000000000001
  42
  43 struct boot_option {
  44         uint32_t attr;
  45         uint16_t path_len;
  46         uint16_t title[];
  47 } _packed_;
  48
  49 struct drive_path {
  50         uint32_t part_nr;
  51         uint64_t part_start;
  52         uint64_t part_size;
  53         char signature[16];
  54         uint8_t mbr_type;
  55         uint8_t signature_type;
  56 } _packed_;
  57
  58 struct device_path {
  59         uint8_t type;
  60         uint8_t sub_type;
  61         uint16_t length;
  62         union {
  63                 uint16_t path[0];
  64                 struct drive_path drive;
  65         };
  66 } _packed_;
  67
  68 bool is_efi_boot(void) {
  69         return access("/sys/firmware/efi", F_OK) >= 0;
  70 }
  71
  72 static int read_flag(const char *varname) {
  73         _cleanup_free_ void *v = NULL;
  74         uint8_t b;
  75         size_t s;
  76         int r;
  77
  78         r = efi_get_variable(EFI_VENDOR_GLOBAL, varname, NULL, &v, &s);
  79         if (r < 0)
  80                 return r;
  81
  82         if (s != 1)
  83                 return -EINVAL;
  84
  85         b = *(uint8_t *)v;
  86         return b > 0;
  87 }
  88
  89 bool is_efi_secure_boot(void) {
  90         return read_flag("SecureBoot") > 0;
  91 }
  92
  93 bool is_efi_secure_boot_setup_mode(void) {
  94         return read_flag("SetupMode") > 0;
  95 }
  96
  97 int efi_reboot_to_firmware_supported(void) {
  98         _cleanup_free_ void *v = NULL;
  99         uint64_t b;
 100         size_t s;
 101         int r;
 102
 103         if (!is_efi_boot() || detect_container() > 0)
 104                 return -EOPNOTSUPP;
 105
 106         r = efi_get_variable(EFI_VENDOR_GLOBAL, "OsIndicationsSupported", NULL, &v, &s);
 107         if (r == -ENOENT) /* variable doesn't exist? it's not supported then */
 108                 return -EOPNOTSUPP;
 109         if (r < 0)
 110                 return r;
 111         if (s != sizeof(uint64_t))
 112                 return -EINVAL;
 113
 114         b = *(uint64_t*) v;
 115         if (!(b & EFI_OS_INDICATIONS_BOOT_TO_FW_UI))
 116                 return -EOPNOTSUPP; /* bit unset? it's not supported then */
 117
 118         return 0;
 119 }
 120
 121 static int get_os_indications(uint64_t *os_indication) {
 122         _cleanup_free_ void *v = NULL;
 123         size_t s;
 124         int r;
 125
 126         r = efi_reboot_to_firmware_supported();
 127         if (r < 0)
 128                 return r;
 129
 130         r = efi_get_variable(EFI_VENDOR_GLOBAL, "OsIndications", NULL, &v, &s);
 131         if (r == -ENOENT) {
 132                 /* Some firmware implementations that do support
 133                  * OsIndications and report that with
 134                  * OsIndicationsSupported will remove the
 135                  * OsIndications variable when it is unset. Let's
 136                  * pretend it's 0 then, to hide this implementation
 137                  * detail. Note that this call will return -ENOENT
 138                  * then only if the support for OsIndications is
 139                  * missing entirely, as determined by
 140                  * efi_reboot_to_firmware_supported() above. */
 141                 *os_indication = 0;
 142                 return 0;
 143         } else if (r < 0)
 144                 return r;
 145         else if (s != sizeof(uint64_t))
 146                 return -EINVAL;
 147
 148         *os_indication = *(uint64_t *)v;
 149         return 0;
 150 }
 151
 152 int efi_get_reboot_to_firmware(void) {
 153         int r;
 154         uint64_t b;
 155
 156         r = get_os_indications(&b);
 157         if (r < 0)
 158                 return r;
 159
 160         return !!(b & EFI_OS_INDICATIONS_BOOT_TO_FW_UI);
 161 }
 162
 163 int efi_set_reboot_to_firmware(bool value) {
 164         int r;
 165         uint64_t b, b_new;
 166
 167         r = get_os_indications(&b);
 168         if (r < 0)
 169                 return r;
 170
 171         if (value)
 172                 b_new = b | EFI_OS_INDICATIONS_BOOT_TO_FW_UI;
 173         else
 174                 b_new = b & ~EFI_OS_INDICATIONS_BOOT_TO_FW_UI;
 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_VENDOR_GLOBAL, "OsIndications", &b_new, sizeof(uint64_t));
 179
 180         return 0;
 181 }
 182
 183 int efi_get_variable(
 184                 sd_id128_t vendor,
 185                 const char *name,
 186                 uint32_t *attribute,
 187                 void **value,
 188                 size_t *size) {
 189
 190         _cleanup_close_ int fd = -1;
 191         _cleanup_free_ char *p = NULL;
 192         uint32_t a;
 193         ssize_t n;
 194         struct stat st;
 195         _cleanup_free_ void *buf = NULL;
 196
 197         assert(name);
 198         assert(value);
 199         assert(size);
 200
 201         if (asprintf(&p,
 202                      "/sys/firmware/efi/efivars/%s-%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
 203                      name, SD_ID128_FORMAT_VAL(vendor)) < 0)
 204                 return -ENOMEM;
 205
 206         fd = open(p, O_RDONLY|O_NOCTTY|O_CLOEXEC);
 207         if (fd < 0)
 208                 return -errno;
 209
 210         if (fstat(fd, &st) < 0)
 211                 return -errno;
 212         if (st.st_size < 4)
 213                 return -EIO;
 214         if (st.st_size > 4*1024*1024 + 4)
 215                 return -E2BIG;
 216
 217         n = read(fd, &a, sizeof(a));
 218         if (n < 0)
 219                 return -errno;
 220         if (n != sizeof(a))
 221                 return -EIO;
 222
 223         buf = malloc(st.st_size - 4 + 2);
 224         if (!buf)
 225                 return -ENOMEM;
 226
 227         n = read(fd, buf, (size_t) st.st_size - 4);
 228         if (n < 0)
 229                 return -errno;
 230         if (n != (ssize_t) st.st_size - 4)
 231                 return -EIO;
 232
 233         /* Always NUL terminate (2 bytes, to protect UTF-16) */
 234         ((char*) buf)[st.st_size - 4] = 0;
 235         ((char*) buf)[st.st_size - 4 + 1] = 0;
 236
 237         *value = TAKE_PTR(buf);
 238         *size = (size_t) st.st_size - 4;
 239
 240         if (attribute)
 241                 *attribute = a;
 242
 243         return 0;
 244 }
 245
 246 int efi_set_variable(
 247                 sd_id128_t vendor,
 248                 const char *name,
 249                 const void *value,
 250                 size_t size) {
 251
 252         struct var {
 253                 uint32_t attr;
 254                 char buf[];
 255         } _packed_ * _cleanup_free_ buf = NULL;
 256         _cleanup_free_ char *p = NULL;
 257         _cleanup_close_ int fd = -1;
 258
 259         assert(name);
 260         assert(value || size == 0);
 261
 262         if (asprintf(&p,
 263                      "/sys/firmware/efi/efivars/%s-%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
 264                      name, SD_ID128_FORMAT_VAL(vendor)) < 0)
 265                 return -ENOMEM;
 266
 267         if (size == 0) {
 268                 if (unlink(p) < 0)
 269                         return -errno;
 270                 return 0;
 271         }
 272
 273         fd = open(p, O_WRONLY|O_CREAT|O_NOCTTY|O_CLOEXEC, 0644);
 274         if (fd < 0)
 275                 return -errno;
 276
 277         buf = malloc(sizeof(uint32_t) + size);
 278         if (!buf)
 279                 return -ENOMEM;
 280
 281         buf->attr = EFI_VARIABLE_NON_VOLATILE|EFI_VARIABLE_BOOTSERVICE_ACCESS|EFI_VARIABLE_RUNTIME_ACCESS;
 282         memcpy(buf->buf, value, size);
 283
 284         return loop_write(fd, buf, sizeof(uint32_t) + size, false);
 285 }
 286
 287 int efi_get_variable_string(sd_id128_t vendor, const char *name, char **p) {
 288         _cleanup_free_ void *s = NULL;
 289         size_t ss = 0;
 290         int r;
 291         char *x;
 292
 293         r = efi_get_variable(vendor, name, NULL, &s, &ss);
 294         if (r < 0)
 295                 return r;
 296
 297         x = utf16_to_utf8(s, ss);
 298         if (!x)
 299                 return -ENOMEM;
 300
 301         *p = x;
 302         return 0;
 303 }
 304
 305 static size_t utf16_size(const uint16_t *s) {
 306         size_t l = 0;
 307
 308         while (s[l] > 0)
 309                 l++;
 310
 311         return (l+1) * sizeof(uint16_t);
 312 }
 313
 314 static void efi_guid_to_id128(const void *guid, sd_id128_t *id128) {
 315         struct uuid {
 316                 uint32_t u1;
 317                 uint16_t u2;
 318                 uint16_t u3;
 319                 uint8_t u4[8];
 320         } _packed_;
 321         const struct uuid *uuid = guid;
 322
 323         id128->bytes[0] = (uuid->u1 >> 24) & 0xff;
 324         id128->bytes[1] = (uuid->u1 >> 16) & 0xff;
 325         id128->bytes[2] = (uuid->u1 >> 8) & 0xff;
 326         id128->bytes[3] = (uuid->u1) & 0xff;
 327         id128->bytes[4] = (uuid->u2 >> 8) & 0xff;
 328         id128->bytes[5] = (uuid->u2) & 0xff;
 329         id128->bytes[6] = (uuid->u3 >> 8) & 0xff;
 330         id128->bytes[7] = (uuid->u3) & 0xff;
 331         memcpy(&id128->bytes[8], uuid->u4, sizeof(uuid->u4));
 332 }
 333
 334 int efi_get_boot_option(
 335                 uint16_t id,
 336                 char **title,
 337                 sd_id128_t *part_uuid,
 338                 char **path,
 339                 bool *active) {
 340
 341         char boot_id[9];
 342         _cleanup_free_ uint8_t *buf = NULL;
 343         size_t l;
 344         struct boot_option *header;
 345         size_t title_size;
 346         _cleanup_free_ char *s = NULL, *p = NULL;
 347         sd_id128_t p_uuid = SD_ID128_NULL;
 348         int r;
 349
 350         xsprintf(boot_id, "Boot%04X", id);
 351         r = efi_get_variable(EFI_VENDOR_GLOBAL, boot_id, NULL, (void **)&buf, &l);
 352         if (r < 0)
 353                 return r;
 354         if (l < sizeof(struct boot_option))
 355                 return -ENOENT;
 356
 357         header = (struct boot_option *)buf;
 358         title_size = utf16_size(header->title);
 359         if (title_size > l - offsetof(struct boot_option, title))
 360                 return -EINVAL;
 361
 362         if (title) {
 363                 s = utf16_to_utf8(header->title, title_size);
 364                 if (!s)
 365                         return -ENOMEM;
 366         }
 367
 368         if (header->path_len > 0) {
 369                 uint8_t *dbuf;
 370                 size_t dnext;
 371
 372                 dbuf = buf + offsetof(struct boot_option, title) + title_size;
 373                 dnext = 0;
 374                 while (dnext < header->path_len) {
 375                         struct device_path *dpath;
 376
 377                         dpath = (struct device_path *)(dbuf + dnext);
 378                         if (dpath->length < 4)
 379                                 break;
 380
 381                         /* Type 0x7F – End of Hardware Device Path, Sub-Type 0xFF – End Entire Device Path */
 382                         if (dpath->type == END_DEVICE_PATH_TYPE && dpath->sub_type == END_ENTIRE_DEVICE_PATH_SUBTYPE)
 383                                 break;
 384
 385                         dnext += dpath->length;
 386
 387                         /* Type 0x04 – Media Device Path */
 388                         if (dpath->type != MEDIA_DEVICE_PATH)
 389                                 continue;
 390
 391                         /* Sub-Type 1 – Hard Drive */
 392                         if (dpath->sub_type == MEDIA_HARDDRIVE_DP) {
 393                                 /* 0x02 – GUID Partition Table */
 394                                 if (dpath->drive.mbr_type != MBR_TYPE_EFI_PARTITION_TABLE_HEADER)
 395                                         continue;
 396
 397                                 /* 0x02 – GUID signature */
 398                                 if (dpath->drive.signature_type != SIGNATURE_TYPE_GUID)
 399                                         continue;
 400
 401                                 if (part_uuid)
 402                                         efi_guid_to_id128(dpath->drive.signature, &p_uuid);
 403                                 continue;
 404                         }
 405
 406                         /* Sub-Type 4 – File Path */
 407                         if (dpath->sub_type == MEDIA_FILEPATH_DP && !p && path) {
 408                                 p = utf16_to_utf8(dpath->path, dpath->length-4);
 409                                 efi_tilt_backslashes(p);
 410                                 continue;
 411                         }
 412                 }
 413         }
 414
 415         if (title)
 416                 *title = TAKE_PTR(s);
 417         if (part_uuid)
 418                 *part_uuid = p_uuid;
 419         if (path)
 420                 *path = TAKE_PTR(p);
 421         if (active)
 422                 *active = !!(header->attr & LOAD_OPTION_ACTIVE);
 423
 424         return 0;
 425 }
 426
 427 static void to_utf16(uint16_t *dest, const char *src) {
 428         int i;
 429
 430         for (i = 0; src[i] != '\0'; i++)
 431                 dest[i] = src[i];
 432         dest[i] = '\0';
 433 }
 434
 435 struct guid {
 436         uint32_t u1;
 437         uint16_t u2;
 438         uint16_t u3;
 439         uint8_t u4[8];
 440 } _packed_;
 441
 442 static void id128_to_efi_guid(sd_id128_t id, void *guid) {
 443         struct guid *uuid = guid;
 444
 445         uuid->u1 = id.bytes[0] << 24 | id.bytes[1] << 16 | id.bytes[2] << 8 | id.bytes[3];
 446         uuid->u2 = id.bytes[4] << 8 | id.bytes[5];
 447         uuid->u3 = id.bytes[6] << 8 | id.bytes[7];
 448         memcpy(uuid->u4, id.bytes+8, sizeof(uuid->u4));
 449 }
 450
 451 static uint16_t *tilt_slashes(uint16_t *s) {
 452         uint16_t *p;
 453
 454         for (p = s; *p; p++)
 455                 if (*p == '/')
 456                         *p = '\\';
 457
 458         return s;
 459 }
 460
 461 int efi_add_boot_option(uint16_t id, const char *title,
 462                         uint32_t part, uint64_t pstart, uint64_t psize,
 463                         sd_id128_t part_uuid, const char *path) {
 464         char boot_id[9];
 465         size_t size;
 466         size_t title_len;
 467         size_t path_len;
 468         struct boot_option *option;
 469         struct device_path *devicep;
 470         _cleanup_free_ char *buf = NULL;
 471
 472         title_len = (strlen(title)+1) * 2;
 473         path_len = (strlen(path)+1) * 2;
 474
 475         buf = calloc(sizeof(struct boot_option) + title_len +
 476                      sizeof(struct drive_path) +
 477                      sizeof(struct device_path) + path_len, 1);
 478         if (!buf)
 479                 return -ENOMEM;
 480
 481         /* header */
 482         option = (struct boot_option *)buf;
 483         option->attr = LOAD_OPTION_ACTIVE;
 484         option->path_len = offsetof(struct device_path, drive) + sizeof(struct drive_path) +
 485                            offsetof(struct device_path, path) + path_len +
 486                            offsetof(struct device_path, path);
 487         to_utf16(option->title, title);
 488         size = offsetof(struct boot_option, title) + title_len;
 489
 490         /* partition info */
 491         devicep = (struct device_path *)(buf + size);
 492         devicep->type = MEDIA_DEVICE_PATH;
 493         devicep->sub_type = MEDIA_HARDDRIVE_DP;
 494         devicep->length = offsetof(struct device_path, drive) + sizeof(struct drive_path);
 495         devicep->drive.part_nr = part;
 496         devicep->drive.part_start = pstart;
 497         devicep->drive.part_size = psize;
 498         devicep->drive.signature_type = SIGNATURE_TYPE_GUID;
 499         devicep->drive.mbr_type = MBR_TYPE_EFI_PARTITION_TABLE_HEADER;
 500         id128_to_efi_guid(part_uuid, devicep->drive.signature);
 501         size += devicep->length;
 502
 503         /* path to loader */
 504         devicep = (struct device_path *)(buf + size);
 505         devicep->type = MEDIA_DEVICE_PATH;
 506         devicep->sub_type = MEDIA_FILEPATH_DP;
 507         devicep->length = offsetof(struct device_path, path) + path_len;
 508         to_utf16(devicep->path, path);
 509         tilt_slashes(devicep->path);
 510         size += devicep->length;
 511
 512         /* end of path */
 513         devicep = (struct device_path *)(buf + size);
 514         devicep->type = END_DEVICE_PATH_TYPE;
 515         devicep->sub_type = END_ENTIRE_DEVICE_PATH_SUBTYPE;
 516         devicep->length = offsetof(struct device_path, path);
 517         size += devicep->length;
 518
 519         xsprintf(boot_id, "Boot%04X", id);
 520         return efi_set_variable(EFI_VENDOR_GLOBAL, boot_id, buf, size);
 521 }
 522
 523 int efi_remove_boot_option(uint16_t id) {
 524         char boot_id[9];
 525
 526         xsprintf(boot_id, "Boot%04X", id);
 527         return efi_set_variable(EFI_VENDOR_GLOBAL, boot_id, NULL, 0);
 528 }
 529
 530 int efi_get_boot_order(uint16_t **order) {
 531         _cleanup_free_ void *buf = NULL;
 532         size_t l;
 533         int r;
 534
 535         r = efi_get_variable(EFI_VENDOR_GLOBAL, "BootOrder", NULL, &buf, &l);
 536         if (r < 0)
 537                 return r;
 538
 539         if (l <= 0)
 540                 return -ENOENT;
 541
 542         if (l % sizeof(uint16_t) > 0 ||
 543             l / sizeof(uint16_t) > INT_MAX)
 544                 return -EINVAL;
 545
 546         *order = TAKE_PTR(buf);
 547         return (int) (l / sizeof(uint16_t));
 548 }
 549
 550 int efi_set_boot_order(uint16_t *order, size_t n) {
 551         return efi_set_variable(EFI_VENDOR_GLOBAL, "BootOrder", order, n * sizeof(uint16_t));
 552 }
 553
 554 static int boot_id_hex(const char s[4]) {
 555         int i;
 556         int id = 0;
 557
 558         for (i = 0; i < 4; i++)
 559                 if (s[i] >= '0' && s[i] <= '9')
 560                         id |= (s[i] - '0') << (3 - i) * 4;
 561                 else if (s[i] >= 'A' && s[i] <= 'F')
 562                         id |= (s[i] - 'A' + 10) << (3 - i) * 4;
 563                 else
 564                         return -EINVAL;
 565
 566         return id;
 567 }
 568
 569 static int cmp_uint16(const void *_a, const void *_b) {
 570         const uint16_t *a = _a, *b = _b;
 571
 572         return (int)*a - (int)*b;
 573 }
 574
 575 int efi_get_boot_options(uint16_t **options) {
 576         _cleanup_closedir_ DIR *dir = NULL;
 577         struct dirent *de;
 578         _cleanup_free_ uint16_t *list = NULL;
 579         size_t alloc = 0;
 580         int count = 0;
 581
 582         assert(options);
 583
 584         dir = opendir("/sys/firmware/efi/efivars/");
 585         if (!dir)
 586                 return -errno;
 587
 588         FOREACH_DIRENT(de, dir, return -errno) {
 589                 int id;
 590
 591                 if (strncmp(de->d_name, "Boot", 4) != 0)
 592                         continue;
 593
 594                 if (strlen(de->d_name) != 45)
 595                         continue;
 596
 597                 if (strcmp(de->d_name + 8, "-8be4df61-93ca-11d2-aa0d-00e098032b8c") != 0)
 598                         continue;
 599
 600                 id = boot_id_hex(de->d_name + 4);
 601                 if (id < 0)
 602                         continue;
 603
 604                 if (!GREEDY_REALLOC(list, alloc, count + 1))
 605                         return -ENOMEM;
 606
 607                 list[count++] = id;
 608         }
 609
 610         qsort_safe(list, count, sizeof(uint16_t), cmp_uint16);
 611
 612         *options = TAKE_PTR(list);
 613
 614         return count;
 615 }
 616
 617 static int read_usec(sd_id128_t vendor, const char *name, usec_t *u) {
 618         _cleanup_free_ char *j = NULL;
 619         int r;
 620         uint64_t x = 0;
 621
 622         assert(name);
 623         assert(u);
 624
 625         r = efi_get_variable_string(EFI_VENDOR_LOADER, name, &j);
 626         if (r < 0)
 627                 return r;
 628
 629         r = safe_atou64(j, &x);
 630         if (r < 0)
 631                 return r;
 632
 633         *u = x;
 634         return 0;
 635 }
 636
 637 int efi_loader_get_boot_usec(usec_t *firmware, usec_t *loader) {
 638         uint64_t x, y;
 639         int r;
 640
 641         assert(firmware);
 642         assert(loader);
 643
 644         r = read_usec(EFI_VENDOR_LOADER, "LoaderTimeInitUSec", &x);
 645         if (r < 0)
 646                 return r;
 647
 648         r = read_usec(EFI_VENDOR_LOADER, "LoaderTimeExecUSec", &y);
 649         if (r < 0)
 650                 return r;
 651
 652         if (y == 0 || y < x)
 653                 return -EIO;
 654
 655         if (y > USEC_PER_HOUR)
 656                 return -EIO;
 657
 658         *firmware = x;
 659         *loader = y;
 660
 661         return 0;
 662 }
 663
 664 int efi_loader_get_device_part_uuid(sd_id128_t *u) {
 665         _cleanup_free_ char *p = NULL;
 666         int r, parsed[16];
 667
 668         r = efi_get_variable_string(EFI_VENDOR_LOADER, "LoaderDevicePartUUID", &p);
 669         if (r < 0)
 670                 return r;
 671
 672         if (sscanf(p, "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x",
 673                    &parsed[0], &parsed[1], &parsed[2], &parsed[3],
 674                    &parsed[4], &parsed[5], &parsed[6], &parsed[7],
 675                    &parsed[8], &parsed[9], &parsed[10], &parsed[11],
 676                    &parsed[12], &parsed[13], &parsed[14], &parsed[15]) != 16)
 677                 return -EIO;
 678
 679         if (u) {
 680                 unsigned i;
 681
 682                 for (i = 0; i < ELEMENTSOF(parsed); i++)
 683                         u->bytes[i] = parsed[i];
 684         }
 685
 686         return 0;
 687 }
 688
 689 #endif
 690
 691 char *efi_tilt_backslashes(char *s) {
 692         char *p;
 693
 694         for (p = s; *p; p++)
 695                 if (*p == '\\')
 696                         *p = '/';
 697
 698         return s;
 699 }