diff options
Diffstat (limited to 'src/libsystemd/sd-id128/id128-util.c')
| -rw-r--r-- | src/libsystemd/sd-id128/id128-util.c | 265 |
1 files changed, 265 insertions, 0 deletions
diff --git a/src/libsystemd/sd-id128/id128-util.c b/src/libsystemd/sd-id128/id128-util.c new file mode 100644 index 0000000..94bfd70 --- /dev/null +++ b/src/libsystemd/sd-id128/id128-util.c @@ -0,0 +1,265 @@ +/* SPDX-License-Identifier: LGPL-2.1-or-later */ + +#include <errno.h> +#include <fcntl.h> +#include <unistd.h> + +#include "fd-util.h" +#include "fs-util.h" +#include "hexdecoct.h" +#include "id128-util.h" +#include "io-util.h" +#include "sha256.h" +#include "stdio-util.h" +#include "string-util.h" +#include "sync-util.h" +#include "virt.h" + +int id128_from_string_nonzero(const char *s, sd_id128_t *ret) { + sd_id128_t t; + int r; + + assert(ret); + + r = sd_id128_from_string(ASSERT_PTR(s), &t); + if (r < 0) + return r; + + if (sd_id128_is_null(t)) + return -ENXIO; + + *ret = t; + return 0; +} + +bool id128_is_valid(const char *s) { + size_t l; + + assert(s); + + l = strlen(s); + + if (l == SD_ID128_STRING_MAX - 1) + /* Plain formatted 128-bit hex string */ + return in_charset(s, HEXDIGITS); + + if (l == SD_ID128_UUID_STRING_MAX - 1) { + /* Formatted UUID */ + for (size_t i = 0; i < l; i++) { + char c = s[i]; + + if (IN_SET(i, 8, 13, 18, 23)) { + if (c != '-') + return false; + } else if (!ascii_ishex(c)) + return false; + } + return true; + } + + return false; +} + +int id128_read_fd(int fd, Id128Flag f, sd_id128_t *ret) { + char buffer[SD_ID128_UUID_STRING_MAX + 1]; /* +1 is for trailing newline */ + sd_id128_t id; + ssize_t l; + int r; + + assert(fd >= 0); + + /* Reads an 128-bit ID from a file, which may either be in plain format (32 hex digits), or in UUID format, both + * optionally followed by a newline and nothing else. ID files should really be newline terminated, but if they + * aren't that's OK too, following the rule of "Be conservative in what you send, be liberal in what you + * accept". + * + * This returns the following: + * -ENOMEDIUM: an empty string, + * -ENOPKG: "uninitialized" or "uninitialized\n", + * -EUCLEAN: other invalid strings. */ + + l = loop_read(fd, buffer, sizeof(buffer), false); /* we expect a short read of either 32/33 or 36/37 chars */ + if (l < 0) + return (int) l; + if (l == 0) /* empty? */ + return -ENOMEDIUM; + + switch (l) { + + case STRLEN("uninitialized"): + case STRLEN("uninitialized\n"): + return strneq(buffer, "uninitialized\n", l) ? -ENOPKG : -EINVAL; + + case SD_ID128_STRING_MAX: /* plain UUID with trailing newline */ + if (buffer[SD_ID128_STRING_MAX-1] != '\n') + return -EUCLEAN; + + _fallthrough_; + case SD_ID128_STRING_MAX-1: /* plain UUID without trailing newline */ + if (!FLAGS_SET(f, ID128_FORMAT_PLAIN)) + return -EUCLEAN; + + buffer[SD_ID128_STRING_MAX-1] = 0; + break; + + case SD_ID128_UUID_STRING_MAX: /* RFC UUID with trailing newline */ + if (buffer[SD_ID128_UUID_STRING_MAX-1] != '\n') + return -EUCLEAN; + + _fallthrough_; + case SD_ID128_UUID_STRING_MAX-1: /* RFC UUID without trailing newline */ + if (!FLAGS_SET(f, ID128_FORMAT_UUID)) + return -EUCLEAN; + + buffer[SD_ID128_UUID_STRING_MAX-1] = 0; + break; + + default: + return -EUCLEAN; + } + + r = sd_id128_from_string(buffer, &id); + if (r == -EINVAL) + return -EUCLEAN; + if (r < 0) + return r; + + if (FLAGS_SET(f, ID128_REFUSE_NULL) && sd_id128_is_null(id)) + return -ENOMEDIUM; + + if (ret) + *ret = id; + return 0; +} + +int id128_read_at(int dir_fd, const char *path, Id128Flag f, sd_id128_t *ret) { + _cleanup_close_ int fd = -EBADF; + + assert(dir_fd >= 0 || dir_fd == AT_FDCWD); + assert(path); + + fd = xopenat(dir_fd, path, O_RDONLY|O_CLOEXEC|O_NOCTTY, /* xopen_flags = */ 0, /* mode = */ 0); + if (fd < 0) + return fd; + + return id128_read_fd(fd, f, ret); +} + +int id128_write_fd(int fd, Id128Flag f, sd_id128_t id) { + char buffer[SD_ID128_UUID_STRING_MAX + 1]; /* +1 is for trailing newline */ + size_t sz; + int r; + + assert(fd >= 0); + assert(IN_SET((f & ID128_FORMAT_ANY), ID128_FORMAT_PLAIN, ID128_FORMAT_UUID)); + + if (FLAGS_SET(f, ID128_REFUSE_NULL) && sd_id128_is_null(id)) + return -ENOMEDIUM; + + if (FLAGS_SET(f, ID128_FORMAT_PLAIN)) { + assert_se(sd_id128_to_string(id, buffer)); + sz = SD_ID128_STRING_MAX; + } else { + assert_se(sd_id128_to_uuid_string(id, buffer)); + sz = SD_ID128_UUID_STRING_MAX; + } + + buffer[sz - 1] = '\n'; + r = loop_write(fd, buffer, sz); + if (r < 0) + return r; + + if (FLAGS_SET(f, ID128_SYNC_ON_WRITE)) { + r = fsync_full(fd); + if (r < 0) + return r; + } + + return 0; +} + +int id128_write_at(int dir_fd, const char *path, Id128Flag f, sd_id128_t id) { + _cleanup_close_ int fd = -EBADF; + + assert(dir_fd >= 0 || dir_fd == AT_FDCWD); + assert(path); + + fd = xopenat(dir_fd, path, O_WRONLY|O_CREAT|O_CLOEXEC|O_NOCTTY|O_TRUNC, /* xopen_flags = */ 0, 0444); + if (fd < 0) + return fd; + + return id128_write_fd(fd, f, id); +} + +void id128_hash_func(const sd_id128_t *p, struct siphash *state) { + siphash24_compress(p, sizeof(sd_id128_t), state); +} + +int id128_compare_func(const sd_id128_t *a, const sd_id128_t *b) { + return memcmp(a, b, 16); +} + +sd_id128_t id128_make_v4_uuid(sd_id128_t id) { + /* Stolen from generate_random_uuid() of drivers/char/random.c + * in the kernel sources */ + + /* Set UUID version to 4 --- truly random generation */ + id.bytes[6] = (id.bytes[6] & 0x0F) | 0x40; + + /* Set the UUID variant to DCE */ + id.bytes[8] = (id.bytes[8] & 0x3F) | 0x80; + + return id; +} + +DEFINE_HASH_OPS(id128_hash_ops, sd_id128_t, id128_hash_func, id128_compare_func); +DEFINE_HASH_OPS_WITH_KEY_DESTRUCTOR(id128_hash_ops_free, sd_id128_t, id128_hash_func, id128_compare_func, free); + +int id128_get_product(sd_id128_t *ret) { + sd_id128_t uuid; + int r; + + assert(ret); + + /* Reads the systems product UUID from DMI or devicetree (where it is located on POWER). This is + * particularly relevant in VM environments, where VM managers typically place a VM uuid there. */ + + r = detect_container(); + if (r < 0) + return r; + if (r > 0) /* Refuse returning this in containers, as this is not a property of our system then, but + * of the host */ + return -ENOENT; + + r = id128_read("/sys/class/dmi/id/product_uuid", ID128_FORMAT_UUID, &uuid); + if (r == -ENOENT) + r = id128_read("/proc/device-tree/vm,uuid", ID128_FORMAT_UUID, &uuid); + if (r == -ENOENT) + r = id128_read("/sys/hypervisor/uuid", ID128_FORMAT_UUID, &uuid); + if (r < 0) + return r; + + if (sd_id128_is_null(uuid) || sd_id128_is_allf(uuid)) + return -EADDRNOTAVAIL; /* Recognizable error */ + + *ret = uuid; + return 0; +} + +sd_id128_t id128_digest(const void *data, size_t size) { + assert(data || size == 0); + + /* Hashes a UUID from some arbitrary data */ + + if (size == SIZE_MAX) + size = strlen(data); + + uint8_t h[SHA256_DIGEST_SIZE]; + sd_id128_t id; + + /* Take the first half of the SHA256 result */ + assert_cc(sizeof(h) >= sizeof(id.bytes)); + memcpy(id.bytes, sha256_direct(data, size, h), sizeof(id.bytes)); + + return id128_make_v4_uuid(id); +} |