journal: add preliminary incomplete implementation

[elogind.git] / src / sd-id128.c

diff --git a/src/sd-id128.c b/src/sd-id128.c
new file mode 100644 (file)
index 0000000..f5e0432
--- /dev/null
+++ b/src/sd-id128.c
@@ -0,0 +1,210 @@
+/*-*- 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"
+
+char *sd_id128_to_string(sd_id128_t id, char s[33]) {
+        unsigned n;
+
+        assert(s);
+
+        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;
+}
+
+int sd_id128_from_string(const char s[33], sd_id128_t *ret) {
+        unsigned n;
+        sd_id128_t t;
+
+        assert(s);
+        assert(ret);
+
+        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;
+}
+
+sd_id128_t sd_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;
+}
+
+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 (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;
+}
+
+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 (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;
+}
+
+int sd_id128_randomize(sd_id128_t *ret) {
+        int fd;
+        ssize_t k;
+        sd_id128_t t;
+
+        assert(ret);
+
+        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 = sd_id128_make_v4_uuid(t);
+        return 0;
+}