run: expand variables also with --scope

This makes syntax be the same for commands which are started by the manager and
those which are spawned directly (when --scope is used).

Before:
$ systemd-run -q -t echo '$TERM'
xterm-256color

$ systemd-run -q --scope echo '$TERM'
$TERM

Now:
$ systemd-run -q --scope echo '$TERM'
xterm-256color

Previous behaviour can be restored via --expand-environment=no:
$ systemd-run -q --scope --expand-environment=no echo '$TERM'
$TERM

Fixes #22948.

At some level, this is a compat break. Fortunately --scope is not very widely
used, so I think we can get away with this. Having different syntax depending
on whether --scope was used or not was bad UX.

A NEWS entry will be required.

1 files changed, 9 insertions, 3 deletions

diff --git a/src/run/run.c b/src/run/run.c
index 3ad866aaa6..2f5ec9c73b 100644
--- a/src/run/run.c
+++ b/src/run/run.c
@@ -103,8 +103,7 @@ static int help(void) {
                "     --description=TEXT           Description for unit\n"
                "     --slice=SLICE                Run in the specified slice\n"
                "     --slice-inherit              Inherit the slice\n"
-               "     --expand-environment=BOOL    Control server-side expansion of environment\n"
-               "                                  variables\n"
+               "     --expand-environment=BOOL    Control expansion of environment variables\n"
                "     --no-block                   Do not wait until operation finished\n"
                "  -r --remain-after-exit          Leave service around until explicitly stopped\n"
                "     --wait                       Wait until service stopped again\n"
@@ -1472,7 +1471,7 @@ static int start_transient_scope(sd_bus *bus) {
         _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
         _cleanup_(sd_bus_message_unrefp) sd_bus_message *m = NULL, *reply = NULL;
         _cleanup_(bus_wait_for_jobs_freep) BusWaitForJobs *w = NULL;
-        _cleanup_strv_free_ char **env = NULL, **user_env = NULL;
+        _cleanup_strv_free_ char **env = NULL, **user_env = NULL, **expanded_cmdline = NULL;
         _cleanup_free_ char *scope = NULL;
         const char *object = NULL;
         sd_id128_t invocation_id;
@@ -1614,6 +1613,13 @@ static int start_transient_scope(sd_bus *bus) {
         if (!arg_quiet)
                 log_info("Running scope as unit: %s", scope);
 
+        if (arg_expand_environment) {
+                expanded_cmdline = replace_env_argv(arg_cmdline, env);
+                if (!expanded_cmdline)
+                        return log_oom();
+                arg_cmdline = expanded_cmdline;
+        }
+
         execvpe(arg_cmdline[0], arg_cmdline, env);
 
         return log_error_errno(errno, "Failed to execute: %m");