sd-bus: support connecting to remote hosts, directly into containers

systemctl -H root@foobar:waldi

will now show a list of services running on container "waldi" on host
"foobar", using "root" for authenticating at "foobar".

Since entereing a container requires priviliges, this will only work
correctly for root logins.

2 files changed, 17 insertions, 0 deletions

diff --git a/src/shared/util.c b/src/shared/util.c
index 4ad3f203d7..3d875c72b3 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -3975,6 +3975,21 @@ char* hostname_cleanup(char *s, bool lowercase) {
         return s;
 }
 
+bool machine_name_is_valid(const char *s) {
+
+        if (!hostname_is_valid(s))
+                return false;
+
+        /* Machine names should be useful hostnames, but also be
+         * useful in unit names, hence we enforce a stricter length
+         * limitation. */
+
+        if (strlen(s) > 64)
+                return false;
+
+        return true;
+}
+
 int pipe_eof(int fd) {
         struct pollfd pollfd = {
                 .fd = fd,
diff --git a/src/shared/util.h b/src/shared/util.h
index 6d3791be7f..e23069c016 100644
--- a/src/shared/util.h
+++ b/src/shared/util.h
@@ -515,6 +515,8 @@ bool plymouth_running(void);
 bool hostname_is_valid(const char *s) _pure_;
 char* hostname_cleanup(char *s, bool lowercase);
 
+bool machine_name_is_valid(const char *s) _pure_;
+
 char* strshorten(char *s, size_t l);
 
 int terminal_vhangup_fd(int fd);