1 files changed, 63 insertions, 0 deletions
diff --git a/src/core/hostname-setup.c b/src/core/hostname-setup.c
new file mode 100644
index 0000000..867ea19
--- /dev/null
+++ b/src/core/hostname-setup.c
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include "alloc-util.h"
+#include "fileio.h"
+#include "hostname-setup.h"
+#include "hostname-util.h"
+#include "log.h"
+#include "macro.h"
+#include "proc-cmdline.h"
+#include "string-util.h"
+#include "util.h"
+
+int hostname_setup(void) {
+        _cleanup_free_ char *b = NULL;
+        const char *hn = NULL;
+        bool enoent = false;
+        int r;
+
+        r = proc_cmdline_get_key("systemd.hostname", 0, &b);
+        if (r < 0)
+                log_warning_errno(r, "Failed to retrieve system hostname from kernel command line, ignoring: %m");
+        else if (r > 0) {
+                if (hostname_is_valid(b, true))
+                        hn = b;
+                else  {
+                        log_warning("Hostname specified on kernel command line is invalid, ignoring: %s", b);
+                        b = mfree(b);
+                }
+        }
+
+        if (!hn) {
+                r = read_etc_hostname(NULL, &b);
+                if (r < 0) {
+                        if (r == -ENOENT)
+                                enoent = true;
+                        else
+                                log_warning_errno(r, "Failed to read configured hostname: %m");
+                } else
+                        hn = b;
+        }
+
+        if (isempty(hn)) {
+                /* Don't override the hostname if it is already set and not explicitly configured */
+                if (hostname_is_set())
+                        return 0;
+
+                if (enoent)
+                        log_info("No hostname configured.");
+
+                hn = FALLBACK_HOSTNAME;
+        }
+
+        r = sethostname_idempotent(hn);
+        if (r < 0)
+                return log_warning_errno(r, "Failed to set hostname to <%s>: %m", hn);
+
+        log_info("Set hostname to <%s>.", hn);
+        return 0;
+}