1 files changed, 92 insertions, 0 deletions
diff --git a/src/id.c b/src/id.c
new file mode 100644
index 0000000..6095ef6
--- /dev/null
+++ b/src/id.c
@@ -0,0 +1,92 @@
+// SPDX-License-Identifier: BSD-3-Clause
+
+#include <assert.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/statfs.h>
+#include <sys/types.h>
+#include <sys/vfs.h>
+
+#include "id.h"
+#include "util.h"
+
+#ifdef HAVE_UDEV
+
+#endif
+
+#ifdef HAVE_UTIL_LINUX
+
+#endif
+
+static char *really_get_machine_id() {
+#ifdef MACHINE_ID_PATH
+    FILE *machine_id_file = fopen(MACHINE_ID_PATH, "r");
+#else
+    const char *etc_machine_id = "/etc/machine-id";
+    const char *var_lib_dbus_machine_id = "/var/lib/dbus/machine-id";
+    FILE *machine_id_file = fopen(etc_machine_id, "r");
+    if (!machine_id_file) {
+        if (errno != ENOENT)
+            fprintf(stderr, "error opening %s: %s, trying %s\n",
+                    etc_machine_id, strerror(errno), var_lib_dbus_machine_id);
+        machine_id_file = fopen(var_lib_dbus_machine_id, "r");
+    }
+#endif
+
+    if (!machine_id_file) {
+        perror("couldn't open any machine-id file, last error");
+        return NULL;
+    }
+
+    char *machine_id = NULL;
+    size_t machine_id_len = 0;
+    if (getdelim(&machine_id, &machine_id_len, '\0', machine_id_file) == -1) {
+        fputs("error reading machine id file\n", stderr);
+        free(machine_id);
+        return NULL;
+    }
+
+    return machine_id;
+}
+
+size_t get_machine_id(char **machine_id) {
+    static char *c_machine_id;
+    if (!c_machine_id)
+        c_machine_id = really_get_machine_id();
+    *machine_id = c_machine_id;
+    return strlen(*machine_id);
+}
+
+size_t get_fs_id(fsid_t *fs_id, int seed_fd) {
+    struct statfs statfs_buf;
+    if (fstatfs(seed_fd, &statfs_buf) == -1) {
+        perror("error: statfs seed file: %s");
+        return false;
+    }
+
+    switch (statfs_buf.f_type) {
+        case 0x9123683e: // BTRFS_SUPER_MAGIC
+        case 0xef53: // EXT2_SUPER_MAGIC == EXT3_SUPER_MAGIC == EXT4_SUPER_MAGIC
+        case 0x3153464a: // JFS_SUPER_MAGIC
+        case 0x5346544e: // NTFS_SB_MAGIC
+        case 0x52654973: // REISERFS_SUPER_MAGIC
+        case 0x24051905: // UBIFS_SUPER_MAGIC
+            memcpy(fs_id, &statfs_buf.f_fsid, sizeof(fsid_t));
+            return sizeof(fsid_t);
+        default:
+            fprintf(stderr, "error: filesystem type 0x%08x does not have consistent f_fsid\n", (unsigned int)statfs_buf.f_type);
+            return 0;
+    }
+}
+
+void hash(const unsigned char salt[static SALT_LEN], unsigned char out[static HASH_LEN], const void *in, size_t size) {
+    assert(size < INT_MAX - SALT_LEN - 100);
+    sha256_ctx ctx;
+    sha256_init(&ctx);
+    sha256_update(&ctx, salt, SALT_LEN);
+    sha256_update(&ctx, in, (unsigned int)size);
+    sha256_final(&ctx, out);
+}