diff options
Diffstat (limited to 'src/sd-id128.c')
| -rw-r--r-- | src/sd-id128.c | 221 |
1 files changed, 221 insertions, 0 deletions
diff --git a/src/sd-id128.c b/src/sd-id128.c new file mode 100644 index 000000000..b4184e1c7 --- /dev/null +++ b/src/sd-id128.c @@ -0,0 +1,221 @@ +/*-*- 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; +} |