Adding upstream version 255.4.upstream/255.4

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 213 insertions, 0 deletions

diff --git a/src/shared/hostname-setup.c b/src/shared/hostname-setup.c
new file mode 100644
index 0000000..137c29a
--- /dev/null
+++ b/src/shared/hostname-setup.c
@@ -0,0 +1,213 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <sys/utsname.h>
+#include <unistd.h>
+
+#include "alloc-util.h"
+#include "fd-util.h"
+#include "fileio.h"
+#include "fs-util.h"
+#include "hostname-setup.h"
+#include "hostname-util.h"
+#include "log.h"
+#include "macro.h"
+#include "proc-cmdline.h"
+#include "string-table.h"
+#include "string-util.h"
+
+static int sethostname_idempotent_full(const char *s, bool really) {
+        struct utsname u;
+
+        assert(s);
+
+        assert_se(uname(&u) >= 0);
+
+        if (streq_ptr(s, u.nodename))
+                return 0;
+
+        if (really &&
+            sethostname(s, strlen(s)) < 0)
+                return -errno;
+
+        return 1;
+}
+
+int sethostname_idempotent(const char *s) {
+        return sethostname_idempotent_full(s, true);
+}
+
+int shorten_overlong(const char *s, char **ret) {
+        char *h, *p;
+
+        /* Shorten an overlong name to HOST_NAME_MAX or to the first dot,
+         * whatever comes earlier. */
+
+        assert(s);
+
+        h = strdup(s);
+        if (!h)
+                return -ENOMEM;
+
+        if (hostname_is_valid(h, 0)) {
+                *ret = h;
+                return 0;
+        }
+
+        p = strchr(h, '.');
+        if (p)
+                *p = 0;
+
+        strshorten(h, HOST_NAME_MAX);
+
+        if (!hostname_is_valid(h, 0)) {
+                free(h);
+                return -EDOM;
+        }
+
+        *ret = h;
+        return 1;
+}
+
+int read_etc_hostname_stream(FILE *f, char **ret) {
+        int r;
+
+        assert(f);
+        assert(ret);
+
+        for (;;) {
+                _cleanup_free_ char *line = NULL;
+
+                r = read_stripped_line(f, LONG_LINE_MAX, &line);
+                if (r < 0)
+                        return r;
+                if (r == 0) /* EOF without any hostname? the file is empty, let's treat that exactly like no file at all: ENOENT */
+                        return -ENOENT;
+
+                /* File may have empty lines or comments, ignore them */
+                if (IN_SET(line[0], '\0', '#'))
+                        continue;
+
+                hostname_cleanup(line); /* normalize the hostname */
+
+                if (!hostname_is_valid(line, VALID_HOSTNAME_TRAILING_DOT)) /* check that the hostname we return is valid */
+                        return -EBADMSG;
+
+                *ret = TAKE_PTR(line);
+                return 0;
+        }
+}
+
+int read_etc_hostname(const char *path, char **ret) {
+        _cleanup_fclose_ FILE *f = NULL;
+
+        assert(ret);
+
+        if (!path)
+                path = "/etc/hostname";
+
+        f = fopen(path, "re");
+        if (!f)
+                return -errno;
+
+        return read_etc_hostname_stream(f, ret);
+}
+
+void hostname_update_source_hint(const char *hostname, HostnameSource source) {
+        int r;
+
+        /* Why save the value and not just create a flag file? This way we will
+         * notice if somebody sets the hostname directly (not going through hostnamed).
+         */
+
+        if (source == HOSTNAME_DEFAULT) {
+                r = write_string_file("/run/systemd/default-hostname", hostname,
+                                      WRITE_STRING_FILE_CREATE | WRITE_STRING_FILE_ATOMIC);
+                if (r < 0)
+                        log_warning_errno(r, "Failed to create \"/run/systemd/default-hostname\": %m");
+        } else
+                unlink_or_warn("/run/systemd/default-hostname");
+}
+
+int hostname_setup(bool really) {
+        _cleanup_free_ char *b = NULL;
+        const char *hn = NULL;
+        HostnameSource source;
+        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, VALID_HOSTNAME_TRAILING_DOT)) {
+                        hn = b;
+                        source = HOSTNAME_TRANSIENT;
+                } 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;
+                        source = HOSTNAME_STATIC;
+                }
+        }
+
+        if (!hn) {
+                _cleanup_free_ char *buf = NULL;
+
+                /* Don't override the hostname if it is already set and not explicitly configured */
+
+                r = gethostname_full(GET_HOSTNAME_ALLOW_LOCALHOST, &buf);
+                if (r == -ENOMEM)
+                        return log_oom();
+                if (r >= 0) {
+                        log_debug("No hostname configured, leaving existing hostname <%s> in place.", buf);
+                        return 0;
+                }
+
+                if (enoent)
+                        log_info("No hostname configured, using default hostname.");
+
+                hn = b = get_default_hostname();
+                if (!hn)
+                        return log_oom();
+
+                source = HOSTNAME_DEFAULT;
+
+        }
+
+        r = sethostname_idempotent_full(hn, really);
+        if (r < 0)
+                return log_warning_errno(r, "Failed to set hostname to <%s>: %m", hn);
+        if (r == 0)
+                log_debug("Hostname was already set to <%s>.", hn);
+        else
+                log_info("Hostname %s to <%s>.",
+                         really ? "set" : "would have been set",
+                         hn);
+
+        if (really)
+                hostname_update_source_hint(hn, source);
+
+        return r;
+}
+
+static const char* const hostname_source_table[] = {
+        [HOSTNAME_STATIC]    = "static",
+        [HOSTNAME_TRANSIENT] = "transient",
+        [HOSTNAME_DEFAULT]   = "default",
+};
+
+DEFINE_STRING_TABLE_LOOKUP(hostname_source, HostnameSource);