diff options
Diffstat (limited to 'src/libsystemd/sd-id128/sd-id128.c')
| -rw-r--r-- | src/libsystemd/sd-id128/sd-id128.c | 234 |
1 files changed, 234 insertions, 0 deletions
diff --git a/src/libsystemd/sd-id128/sd-id128.c b/src/libsystemd/sd-id128/sd-id128.c new file mode 100644 index 0000000000..9ee40ab91e --- /dev/null +++ b/src/libsystemd/sd-id128/sd-id128.c @@ -0,0 +1,234 @@ +/*-*- Mode: C; c-basic-offset: 8; indent-tabs-mode: nil -*-*/ + +/*** + This file is part of systemd. + + Copyright 2011 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 <errno.h> +#include <fcntl.h> +#include <unistd.h> + +#include "util.h" +#include "macro.h" +#include "sd-id128.h" + +_public_ char *sd_id128_to_string(sd_id128_t id, char s[33]) { + unsigned n; + + assert_return(s, NULL); + + for (n = 0; n < 16; n++) { + s[n*2] = hexchar(id.bytes[n] >> 4); + s[n*2+1] = hexchar(id.bytes[n] & 0xF); + } + + s[32] = 0; + + return s; +} + +_public_ int sd_id128_from_string(const char s[], sd_id128_t *ret) { + unsigned n, i; + sd_id128_t t; + bool is_guid = false; + + assert_return(s, -EINVAL); + assert_return(ret, -EINVAL); + + for (n = 0, i = 0; n < 16;) { + int a, b; + + if (s[i] == '-') { + /* Is this a GUID? Then be nice, and skip over + * the dashes */ + + if (i == 8) + is_guid = true; + else if (i == 13 || i == 18 || i == 23) { + if (!is_guid) + return -EINVAL; + } else + return -EINVAL; + + i++; + continue; + } + + a = unhexchar(s[i++]); + if (a < 0) + return -EINVAL; + + b = unhexchar(s[i++]); + if (b < 0) + return -EINVAL; + + t.bytes[n++] = (a << 4) | b; + } + + if (i != (is_guid ? 36 : 32)) + return -EINVAL; + + if (s[i] != 0) + return -EINVAL; + + *ret = t; + return 0; +} + +static sd_id128_t 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; +} + +_public_ int sd_id128_get_machine(sd_id128_t *ret) { + static thread_local sd_id128_t saved_machine_id; + static thread_local bool saved_machine_id_valid = false; + _cleanup_close_ int fd = -1; + char buf[33]; + ssize_t k; + unsigned j; + sd_id128_t t; + + assert_return(ret, -EINVAL); + + if (saved_machine_id_valid) { + *ret = saved_machine_id; + return 0; + } + + fd = open("/etc/machine-id", O_RDONLY|O_CLOEXEC|O_NOCTTY); + if (fd < 0) + return -errno; + + k = loop_read(fd, buf, 33, false); + if (k < 0) + return (int) k; + + if (k != 33) + return -EIO; + + if (buf[32] !='\n') + return -EIO; + + for (j = 0; j < 16; j++) { + int a, b; + + a = unhexchar(buf[j*2]); + b = unhexchar(buf[j*2+1]); + + if (a < 0 || b < 0) + return -EIO; + + t.bytes[j] = a << 4 | b; + } + + saved_machine_id = t; + saved_machine_id_valid = true; + + *ret = t; + return 0; +} + +_public_ int sd_id128_get_boot(sd_id128_t *ret) { + static thread_local sd_id128_t saved_boot_id; + static thread_local bool saved_boot_id_valid = false; + _cleanup_close_ int fd = -1; + char buf[36]; + ssize_t k; + unsigned j; + sd_id128_t t; + char *p; + + assert_return(ret, -EINVAL); + + if (saved_boot_id_valid) { + *ret = saved_boot_id; + return 0; + } + + fd = open("/proc/sys/kernel/random/boot_id", O_RDONLY|O_CLOEXEC|O_NOCTTY); + if (fd < 0) + return -errno; + + k = loop_read(fd, buf, 36, false); + if (k < 0) + return (int) k; + + if (k != 36) + return -EIO; + + for (j = 0, p = buf; j < 16; j++) { + int a, b; + + if (p >= buf + k) + return -EIO; + + if (*p == '-') + p++; + + a = unhexchar(p[0]); + b = unhexchar(p[1]); + + if (a < 0 || b < 0) + return -EIO; + + t.bytes[j] = a << 4 | b; + + p += 2; + } + + saved_boot_id = t; + saved_boot_id_valid = true; + + *ret = t; + return 0; +} + +_public_ int sd_id128_randomize(sd_id128_t *ret) { + _cleanup_close_ int fd = -1; + sd_id128_t t; + ssize_t k; + + assert_return(ret, -EINVAL); + + fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY); + if (fd < 0) + return -errno; + + k = loop_read(fd, &t, 16, false); + if (k < 0) + return (int) k; + + if (k != 16) + return -EIO; + + /* Turn this into a valid v4 UUID, to be nice. Note that we + * only guarantee this for newly generated UUIDs, not for + * pre-existing ones.*/ + + *ret = make_v4_uuid(t); + return 0; +} |