diff options
Diffstat (limited to 'src/shared/efivars.c')
| -rw-r--r-- | src/shared/efivars.c | 503 |
1 files changed, 503 insertions, 0 deletions
diff --git a/src/shared/efivars.c b/src/shared/efivars.c new file mode 100644 index 0000000000..8d004bad33 --- /dev/null +++ b/src/shared/efivars.c @@ -0,0 +1,503 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + This file is part of systemd. + + Copyright 2013 Lennart Poettering + + systemd is free software; you can redistribute it and/or modify it + under the terms of the GNU Lesser General Public License as published by + the Free Software Foundation; either version 2.1 of the License, or + (at your option) any later version. + + systemd is distributed in the hope that it will be useful, but + WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with systemd; If not, see <http://www.gnu.org/licenses/>. +***/ + +#include <unistd.h> +#include <string.h> +#include <fcntl.h> +#include <ctype.h> + +#include "util.h" +#include "utf8.h" +#include "efivars.h" + +#ifdef ENABLE_EFI + +bool is_efi_boot(void) { + return access("/sys/firmware/efi", F_OK) >= 0; +} + +static int read_flag(const char *varname) { + int r; + void *v; + size_t s; + uint8_t b; + + r = efi_get_variable(EFI_VENDOR_GLOBAL, varname, NULL, &v, &s); + if (r < 0) + return r; + + if (s != 1) { + r = -EINVAL; + goto finish; + } + + b = *(uint8_t *)v; + r = b > 0; +finish: + free(v); + return r; +} + +int is_efi_secure_boot(void) { + return read_flag("SecureBoot"); +} + +int is_efi_secure_boot_setup_mode(void) { + return read_flag("SetupMode"); +} + +int efi_get_variable( + sd_id128_t vendor, + const char *name, + uint32_t *attribute, + void **value, + size_t *size) { + + _cleanup_close_ int fd = -1; + _cleanup_free_ char *p = NULL; + uint32_t a; + ssize_t n; + struct stat st; + void *r; + + assert(name); + assert(value); + assert(size); + + if (asprintf(&p, + "/sys/firmware/efi/efivars/%s-%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x", + name, SD_ID128_FORMAT_VAL(vendor)) < 0) + return -ENOMEM; + + fd = open(p, O_RDONLY|O_NOCTTY|O_CLOEXEC); + if (fd < 0) + return -errno; + + if (fstat(fd, &st) < 0) + return -errno; + if (st.st_size < 4) + return -EIO; + if (st.st_size > 4*1024*1024 + 4) + return -E2BIG; + + n = read(fd, &a, sizeof(a)); + if (n < 0) + return -errno; + if (n != sizeof(a)) + return -EIO; + + r = malloc(st.st_size - 4 + 2); + if (!r) + return -ENOMEM; + + n = read(fd, r, (size_t) st.st_size - 4); + if (n < 0) { + free(r); + return -errno; + } + if (n != (ssize_t) st.st_size - 4) { + free(r); + return -EIO; + } + + /* Always NUL terminate (2 bytes, to protect UTF-16) */ + ((char*) r)[st.st_size - 4] = 0; + ((char*) r)[st.st_size - 4 + 1] = 0; + + *value = r; + *size = (size_t) st.st_size - 4; + + if (attribute) + *attribute = a; + + return 0; +} + +int efi_get_variable_string(sd_id128_t vendor, const char *name, char **p) { + _cleanup_free_ void *s = NULL; + size_t ss; + int r; + char *x; + + r = efi_get_variable(vendor, name, NULL, &s, &ss); + if (r < 0) + return r; + + x = utf16_to_utf8(s, ss); + if (!x) + return -ENOMEM; + + *p = x; + return 0; +} + +static size_t utf16_size(const uint16_t *s) { + size_t l = 0; + + while (s[l] > 0) + l++; + + return (l+1) * sizeof(uint16_t); +} + +static void efi_guid_to_id128(const void *guid, sd_id128_t *id128) { + struct uuid { + uint32_t u1; + uint16_t u2; + uint16_t u3; + uint8_t u4[8]; + } _packed_; + const struct uuid *uuid = guid; + + id128->bytes[0] = (uuid->u1 >> 24) & 0xff; + id128->bytes[1] = (uuid->u1 >> 16) & 0xff; + id128->bytes[2] = (uuid->u1 >> 8) & 0xff; + id128->bytes[3] = (uuid->u1) & 0xff; + id128->bytes[4] = (uuid->u2 >> 8) & 0xff; + id128->bytes[5] = (uuid->u2) & 0xff; + id128->bytes[6] = (uuid->u3 >> 8) & 0xff; + id128->bytes[7] = (uuid->u3) & 0xff; + memcpy(&id128->bytes[8], uuid->u4, sizeof(uuid->u4)); +} + +int efi_get_boot_option( + uint16_t id, + char **title, + sd_id128_t *part_uuid, + char **path) { + + struct boot_option { + uint32_t attr; + uint16_t path_len; + uint16_t title[]; + } _packed_; + + struct drive_path { + uint32_t part_nr; + uint64_t part_start; + uint64_t part_size; + char signature[16]; + uint8_t mbr_type; + uint8_t signature_type; + } _packed_; + + struct device_path { + uint8_t type; + uint8_t sub_type; + uint16_t length; + union { + uint16_t path[0]; + struct drive_path drive; + }; + } _packed_; + + char boot_id[9]; + _cleanup_free_ uint8_t *buf = NULL; + size_t l; + struct boot_option *header; + size_t title_size; + char *s = NULL; + char *p = NULL; + sd_id128_t p_uuid = SD_ID128_NULL; + int err; + + snprintf(boot_id, sizeof(boot_id), "Boot%04X", id); + err = efi_get_variable(EFI_VENDOR_GLOBAL, boot_id, NULL, (void **)&buf, &l); + if (err < 0) + return err; + if (l < sizeof(struct boot_option)) + return -ENOENT; + + header = (struct boot_option *)buf; + title_size = utf16_size(header->title); + if (title_size > l - offsetof(struct boot_option, title)) + return -EINVAL; + + if (title) { + s = utf16_to_utf8(header->title, title_size); + if (!s) { + err = -ENOMEM; + goto err; + } + } + + if (header->path_len > 0) { + uint8_t *dbuf; + size_t dnext; + + dbuf = buf + offsetof(struct boot_option, title) + title_size; + dnext = 0; + while (dnext < header->path_len) { + struct device_path *dpath; + + dpath = (struct device_path *)(dbuf + dnext); + if (dpath->length < 4) + break; + + /* Type 0x7F – End of Hardware Device Path, Sub-Type 0xFF – End Entire Device Path */ + if (dpath->type == 0x7f && dpath->sub_type == 0xff) + break; + + dnext += dpath->length; + + /* Type 0x04 – Media Device Path */ + if (dpath->type != 0x04) + continue; + + /* Sub-Type 1 – Hard Drive */ + if (dpath->sub_type == 0x01) { + /* 0x02 – GUID Partition Table */ + if (dpath->drive.mbr_type != 0x02) + continue; + + /* 0x02 – GUID signature */ + if (dpath->drive.signature_type != 0x02) + continue; + + if (part_uuid) + efi_guid_to_id128(dpath->drive.signature, &p_uuid); + continue; + } + + /* Sub-Type 4 – File Path */ + if (dpath->sub_type == 0x04 && !p && path) { + p = utf16_to_utf8(dpath->path, dpath->length-4); + continue; + } + } + } + + if (title) + *title = s; + if (part_uuid) + *part_uuid = p_uuid; + if (path) + *path = p; + + return 0; +err: + free(s); + free(p); + return err; +} + +int efi_get_boot_order(uint16_t **order) { + void *buf; + size_t l; + int r; + + r = efi_get_variable(EFI_VENDOR_GLOBAL, "BootOrder", NULL, &buf, &l); + if (r < 0) + return r; + + if (l <= 0) { + free(buf); + return -ENOENT; + } + + if ((l % sizeof(uint16_t) > 0) || + (l / sizeof(uint16_t) > INT_MAX)) { + free(buf); + return -EINVAL; + } + + *order = buf; + return (int) (l / sizeof(uint16_t)); +} + +static int boot_id_hex(const char s[4]) { + int i; + int id = 0; + + for (i = 0; i < 4; i++) + if (s[i] >= '0' && s[i] <= '9') + id |= (s[i] - '0') << (3 - i) * 4; + else if (s[i] >= 'A' && s[i] <= 'F') + id |= (s[i] - 'A' + 10) << (3 - i) * 4; + else + return -1; + + return id; +} + +static int cmp_uint16(const void *_a, const void *_b) { + const uint16_t *a = _a, *b = _b; + + return (int)*a - (int)*b; +} + +int efi_get_boot_options(uint16_t **options) { + _cleanup_closedir_ DIR *dir = NULL; + struct dirent *de; + uint16_t *list = NULL; + int count = 0, r; + + assert(options); + + dir = opendir("/sys/firmware/efi/efivars/"); + if (!dir) + return -errno; + + FOREACH_DIRENT(de, dir, r = -errno; goto fail) { + int id; + uint16_t *t; + + if (strncmp(de->d_name, "Boot", 4) != 0) + continue; + + if (strlen(de->d_name) != 45) + continue; + + if (strcmp(de->d_name + 8, "-8be4df61-93ca-11d2-aa0d-00e098032b8c") != 0) + continue; + + id = boot_id_hex(de->d_name + 4); + if (id < 0) + continue; + + t = realloc(list, (count + 1) * sizeof(uint16_t)); + if (!t) { + r = -ENOMEM; + goto fail; + } + + list = t; + list[count ++] = id; + } + + qsort(list, count, sizeof(uint16_t), cmp_uint16); + + *options = list; + return count; + +fail: + free(list); + return r; +} + +static int read_usec(sd_id128_t vendor, const char *name, usec_t *u) { + _cleanup_free_ char *j = NULL; + int r; + uint64_t x; + + assert(name); + assert(u); + + r = efi_get_variable_string(EFI_VENDOR_LOADER, name, &j); + if (r < 0) + return r; + + r = safe_atou64(j, &x); + if (r < 0) + return r; + + *u = x; + return 0; +} + +static int get_boot_usec(usec_t *firmware, usec_t *loader) { + uint64_t x, y; + int r; + + assert(firmware); + assert(loader); + + r = read_usec(EFI_VENDOR_LOADER, "LoaderTimeInitUSec", &x); + if (r < 0) + return r; + + r = read_usec(EFI_VENDOR_LOADER, "LoaderTimeExecUSec", &y); + if (r < 0) + return r; + + if (y == 0 || y < x) + return -EIO; + + if (y > USEC_PER_HOUR) + return -EIO; + + *firmware = x; + *loader = y; + + return 0; +} + +int efi_get_boot_timestamps(const dual_timestamp *n, dual_timestamp *firmware, dual_timestamp *loader) { + usec_t x, y, a; + int r; + dual_timestamp _n; + + assert(firmware); + assert(loader); + + if (!n) { + dual_timestamp_get(&_n); + n = &_n; + } + + r = get_boot_usec(&x, &y); + if (r < 0) + return r; + + /* Let's convert this to timestamps where the firmware + * began/loader began working. To make this more confusing: + * since usec_t is unsigned and the kernel's monotonic clock + * begins at kernel initialization we'll actually initialize + * the monotonic timestamps here as negative of the actual + * value. */ + + firmware->monotonic = y; + loader->monotonic = y - x; + + a = n->monotonic + firmware->monotonic; + firmware->realtime = n->realtime > a ? n->realtime - a : 0; + + a = n->monotonic + loader->monotonic; + loader->realtime = n->realtime > a ? n->realtime - a : 0; + + return 0; +} + +int efi_get_loader_device_part_uuid(sd_id128_t *u) { + _cleanup_free_ char *p = NULL; + int r, parsed[16]; + unsigned i; + + assert(u); + + r = efi_get_variable_string(EFI_VENDOR_LOADER, "LoaderDevicePartUUID", &p); + if (r < 0) + return r; + + if (sscanf(p, "%02x%02x%02x%02x-%02x%02x-%02x%02x-%02x%02x-%02x%02x%02x%02x%02x%02x", + &parsed[0], &parsed[1], &parsed[2], &parsed[3], + &parsed[4], &parsed[5], &parsed[6], &parsed[7], + &parsed[8], &parsed[9], &parsed[10], &parsed[11], + &parsed[12], &parsed[13], &parsed[14], &parsed[15]) != 16) + return -EIO; + + for (i = 0; i < ELEMENTSOF(parsed); i++) + u->bytes[i] = parsed[i]; + + return 0; +} + +#endif |