1 files changed, 70 insertions, 0 deletions
diff --git a/src/systemctl/systemctl-whoami.c b/src/systemctl/systemctl-whoami.c
new file mode 100644
index 0000000..4ee6592
--- /dev/null
+++ b/src/systemctl/systemctl-whoami.c
@@ -0,0 +1,70 @@
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#include "bus-error.h"
+#include "bus-locator.h"
+#include "systemctl.h"
+#include "systemctl-util.h"
+#include "systemctl-whoami.h"
+#include "parse-util.h"
+
+static int lookup_pid(sd_bus *bus, pid_t pid) {
+        _cleanup_(sd_bus_error_free) sd_bus_error error = SD_BUS_ERROR_NULL;
+        _cleanup_(sd_bus_message_unrefp) sd_bus_message *reply = NULL;
+        _cleanup_free_ char *unit = NULL;
+        const char *path;
+        int r;
+
+        r = bus_call_method(bus, bus_systemd_mgr, "GetUnitByPID", &error, &reply, "u", (uint32_t) pid);
+        if (r < 0)
+                return log_error_errno(r, "Failed to get unit for ourselves: %s", bus_error_message(&error, r));
+
+        r = sd_bus_message_read(reply, "o", &path);
+        if (r < 0)
+                return bus_log_parse_error(r);
+
+        r = unit_name_from_dbus_path(path, &unit);
+        if (r < 0)
+                return log_error_errno(r, "Failed to extract unit name from D-Bus object path '%s': %m", path);
+
+        printf("%s\n", unit);
+        return 0;
+}
+
+int verb_whoami(int argc, char *argv[], void *userdata) {
+        sd_bus *bus;
+        int r;
+
+        r = acquire_bus(BUS_FULL, &bus);
+        if (r < 0)
+                return r;
+
+        char **pids = strv_skip(argv, 1);
+
+        if (strv_isempty(pids)) {
+
+                if (arg_transport != BUS_TRANSPORT_LOCAL)
+                        return log_error_errno(SYNTHETIC_ERRNO(EREMOTE), "Refusing to look up local PID on remote host.");
+
+                return lookup_pid(bus, 0);
+        } else {
+                int ret = 0;
+
+                STRV_FOREACH(p, pids) {
+                        pid_t pid;
+
+                        r = parse_pid(*p, &pid);
+                        if (r < 0) {
+                                log_error_errno(r, "Failed to parse PID: %s", *p);
+                                if (ret >= 0)
+                                        ret = r;
+                                continue;
+                        }
+
+                        r = lookup_pid(bus, pid);
+                        if (r < 0 && ret >= 0)
+                                ret = r;
+                }
+
+                return ret;
+        }
+}