+int efi_set_variable(
+ sd_id128_t vendor,
+ const char *name,
+ const void *value,
+ size_t size) {
+
+ struct var {
+ uint32_t attr;
+ char buf[];
+ } _packed_ * _cleanup_free_ buf = NULL;
+ _cleanup_free_ char *p = NULL;
+ _cleanup_close_ int fd = -1;
+
+ assert(name);
+
+ 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;
+
+ if (size == 0) {
+ if (unlink(p) < 0)
+ return -errno;
+ return 0;
+ }
+
+ fd = open(p, O_WRONLY|O_CREAT|O_NOCTTY|O_CLOEXEC, 0644);
+ if (fd < 0)
+ return -errno;
+
+ buf = malloc(sizeof(uint32_t) + size);
+ if (!buf)
+ return -ENOMEM;
+
+ buf->attr = EFI_VARIABLE_NON_VOLATILE|EFI_VARIABLE_BOOTSERVICE_ACCESS|EFI_VARIABLE_RUNTIME_ACCESS;
+ memcpy(buf->buf, value, size);
+
+ return loop_write(fd, buf, sizeof(uint32_t) + size, false);
+}
+
+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,
+ bool *active) {
+
+ char boot_id[9];
+ _cleanup_free_ uint8_t *buf = NULL;
+ size_t l;
+ struct boot_option *header;
+ size_t title_size;
+ _cleanup_free_ char *s = NULL, *p = NULL;
+ sd_id128_t p_uuid = SD_ID128_NULL;
+ int r;
+
+ xsprintf(boot_id, "Boot%04X", id);
+ r = efi_get_variable(EFI_VENDOR_GLOBAL, boot_id, NULL, (void **)&buf, &l);
+ if (r < 0)
+ return r;
+ 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)
+ return -ENOMEM;
+ }
+
+ 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 == END_DEVICE_PATH_TYPE && dpath->sub_type == END_ENTIRE_DEVICE_PATH_SUBTYPE)
+ break;
+
+ dnext += dpath->length;
+
+ /* Type 0x04 – Media Device Path */
+ if (dpath->type != MEDIA_DEVICE_PATH)
+ continue;
+
+ /* Sub-Type 1 – Hard Drive */
+ if (dpath->sub_type == MEDIA_HARDDRIVE_DP) {
+ /* 0x02 – GUID Partition Table */
+ if (dpath->drive.mbr_type != MBR_TYPE_EFI_PARTITION_TABLE_HEADER)
+ continue;
+
+ /* 0x02 – GUID signature */
+ if (dpath->drive.signature_type != SIGNATURE_TYPE_GUID)
+ continue;
+
+ if (part_uuid)
+ efi_guid_to_id128(dpath->drive.signature, &p_uuid);
+ continue;
+ }
+
+ /* Sub-Type 4 – File Path */
+ if (dpath->sub_type == MEDIA_FILEPATH_DP && !p && path) {
+ p = utf16_to_utf8(dpath->path, dpath->length-4);
+ efi_tilt_backslashes(p);
+ continue;
+ }
+ }
+ }
+
+ if (title) {
+ *title = s;
+ s = NULL;
+ }
+ if (part_uuid)
+ *part_uuid = p_uuid;
+ if (path) {
+ *path = p;
+ p = NULL;
+ }
+ if (active)
+ *active = !!(header->attr & LOAD_OPTION_ACTIVE);
+
+ return 0;
+}
+
+static void to_utf16(uint16_t *dest, const char *src) {
+ int i;
+
+ for (i = 0; src[i] != '\0'; i++)
+ dest[i] = src[i];
+ dest[i] = '\0';
+}
+
+struct guid {
+ uint32_t u1;
+ uint16_t u2;
+ uint16_t u3;
+ uint8_t u4[8];
+} _packed_;
+
+static void id128_to_efi_guid(sd_id128_t id, void *guid) {
+ struct guid *uuid = guid;
+
+ uuid->u1 = id.bytes[0] << 24 | id.bytes[1] << 16 | id.bytes[2] << 8 | id.bytes[3];
+ uuid->u2 = id.bytes[4] << 8 | id.bytes[5];
+ uuid->u3 = id.bytes[6] << 8 | id.bytes[7];
+ memcpy(uuid->u4, id.bytes+8, sizeof(uuid->u4));
+}
+
+static uint16_t *tilt_slashes(uint16_t *s) {
+ uint16_t *p;
+
+ for (p = s; *p; p++)
+ if (*p == '/')
+ *p = '\\';
+
+ return s;
+}
+
+char *efi_tilt_backslashes(char *s) {
+ char *p;
+
+ for (p = s; *p; p++)
+ if (*p == '\\')
+ *p = '/';
+
+ return s;
+}
+
+int efi_add_boot_option(uint16_t id, const char *title,
+ uint32_t part, uint64_t pstart, uint64_t psize,
+ sd_id128_t part_uuid, const char *path) {
+ char boot_id[9];
+ size_t size;
+ size_t title_len;
+ size_t path_len;
+ struct boot_option *option;
+ struct device_path *devicep;
+ _cleanup_free_ char *buf = NULL;
+
+ title_len = (strlen(title)+1) * 2;
+ path_len = (strlen(path)+1) * 2;
+
+ buf = calloc(sizeof(struct boot_option) + title_len +
+ sizeof(struct drive_path) +
+ sizeof(struct device_path) + path_len, 1);
+ if (!buf)
+ return -ENOMEM;
+
+ /* header */
+ option = (struct boot_option *)buf;
+ option->attr = LOAD_OPTION_ACTIVE;
+ option->path_len = offsetof(struct device_path, drive) + sizeof(struct drive_path) +
+ offsetof(struct device_path, path) + path_len +
+ offsetof(struct device_path, path);
+ to_utf16(option->title, title);
+ size = offsetof(struct boot_option, title) + title_len;
+
+ /* partition info */
+ devicep = (struct device_path *)(buf + size);
+ devicep->type = MEDIA_DEVICE_PATH;
+ devicep->sub_type = MEDIA_HARDDRIVE_DP;
+ devicep->length = offsetof(struct device_path, drive) + sizeof(struct drive_path);
+ devicep->drive.part_nr = part;
+ devicep->drive.part_start = pstart;
+ devicep->drive.part_size = psize;
+ devicep->drive.signature_type = SIGNATURE_TYPE_GUID;
+ devicep->drive.mbr_type = MBR_TYPE_EFI_PARTITION_TABLE_HEADER;
+ id128_to_efi_guid(part_uuid, devicep->drive.signature);
+ size += devicep->length;
+
+ /* path to loader */
+ devicep = (struct device_path *)(buf + size);
+ devicep->type = MEDIA_DEVICE_PATH;
+ devicep->sub_type = MEDIA_FILEPATH_DP;
+ devicep->length = offsetof(struct device_path, path) + path_len;
+ to_utf16(devicep->path, path);
+ tilt_slashes(devicep->path);
+ size += devicep->length;
+
+ /* end of path */
+ devicep = (struct device_path *)(buf + size);
+ devicep->type = END_DEVICE_PATH_TYPE;
+ devicep->sub_type = END_ENTIRE_DEVICE_PATH_SUBTYPE;
+ devicep->length = offsetof(struct device_path, path);
+ size += devicep->length;
+
+ xsprintf(boot_id, "Boot%04X", id);
+ return efi_set_variable(EFI_VENDOR_GLOBAL, boot_id, buf, size);
+}
+
+int efi_remove_boot_option(uint16_t id) {
+ char boot_id[9];
+
+ xsprintf(boot_id, "Boot%04X", id);
+ return efi_set_variable(EFI_VENDOR_GLOBAL, boot_id, NULL, 0);
+}
+
+int efi_get_boot_order(uint16_t **order) {
+ _cleanup_free_ void *buf = NULL;
+ size_t l;
+ int r;
+
+ r = efi_get_variable(EFI_VENDOR_GLOBAL, "BootOrder", NULL, &buf, &l);
+ if (r < 0)
+ return r;
+
+ if (l <= 0)
+ return -ENOENT;
+
+ if (l % sizeof(uint16_t) > 0 ||
+ l / sizeof(uint16_t) > INT_MAX)
+ return -EINVAL;
+
+ *order = buf;
+ buf = NULL;
+ return (int) (l / sizeof(uint16_t));
+}
+
+int efi_set_boot_order(uint16_t *order, size_t n) {
+ return efi_set_variable(EFI_VENDOR_GLOBAL, "BootOrder", order, n * 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;
+ _cleanup_free_ uint16_t *list = NULL;
+ size_t alloc = 0;
+ int count = 0;
+
+ assert(options);
+
+ dir = opendir("/sys/firmware/efi/efivars/");
+ if (!dir)
+ return -errno;
+
+ FOREACH_DIRENT(de, dir, return -errno) {
+ int id;
+
+ 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;
+
+ if (!GREEDY_REALLOC(list, alloc, count + 1))
+ return -ENOMEM;
+
+ list[count++] = id;
+ }
+
+ qsort_safe(list, count, sizeof(uint16_t), cmp_uint16);
+
+ *options = list;
+ list = NULL;
+ return count;
+}
+