/*-*- 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 General Public License as published by the Free Software Foundation; either version 2 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 General Public License for more details. You should have received a copy of the GNU General Public License along with systemd; If not, see <http://www.gnu.org/licenses/>. ***/ #include <errno.h> #include <fcntl.h> #include <unistd.h> #include "sd-id128.h" #include "util.h" #include "macro.h" _public_ char *sd_id128_to_string(sd_id128_t id, char s[33]) { unsigned n; if (!s) return 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[33], sd_id128_t *ret) { unsigned n; sd_id128_t t; if (!s) return -EINVAL; if (!ret) return -EINVAL; for (n = 0; n < 16; n++) { int a, b; a = unhexchar(s[n*2]); if (a < 0) return -EINVAL; b = unhexchar(s[n*2+1]); if (b < 0) return -EINVAL; t.bytes[n] = (a << 4) | b; } if (s[32] != 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 sd_id128_t saved_machine_id; static __thread bool saved_machine_id_valid = false; int fd; char buf[32]; ssize_t k; unsigned j; sd_id128_t t; if (!ret) return -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, 32, false); close_nointr_nofail(fd); if (k < 0) return (int) k; if (k < 32) 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 sd_id128_t saved_boot_id; static __thread bool saved_boot_id_valid = false; int fd; char buf[36]; ssize_t k; unsigned j; sd_id128_t t; char *p; if (!ret) return -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); close_nointr_nofail(fd); if (k < 0) return (int) k; if (k < 36) return -EIO; for (j = 0, p = buf; j < 16; j++) { int a, b; 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) { int fd; ssize_t k; sd_id128_t t; if (!ret) return -EINVAL; fd = open("/dev/urandom", O_RDONLY|O_CLOEXEC|O_NOCTTY); if (fd < 0) return -errno; k = loop_read(fd, &t, 16, false); close_nointr_nofail(fd); 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; }