login: implement sd_session_get_service()

3 files changed, 32 insertions, 0 deletions

diff --git a/src/login/libsystemd-login.sym b/src/login/libsystemd-login.sym
index 15e505e83b..3100c17662 100644
--- a/src/login/libsystemd-login.sym
+++ b/src/login/libsystemd-login.sym
@@ -37,4 +37,5 @@ local:
 LIBSYSTEMD_LOGIN_38 {
 global:
         sd_pid_get_unit;
+        sd_session_get_service;
 } LIBSYSTEMD_LOGIN_31;
diff --git a/src/login/sd-login.c b/src/login/sd-login.c
index 8893b1de80..ed98412266 100644
--- a/src/login/sd-login.c
+++ b/src/login/sd-login.c
@@ -415,6 +415,34 @@ _public_ int sd_session_get_seat(const char *session, char **seat) {
         return 0;
 }
 
+_public_ int sd_session_get_service(const char *session, char **service) {
+        char *p, *s = NULL;
+        int r;
+
+        if (!session)
+                return -EINVAL;
+        if (!service)
+                return -EINVAL;
+
+        p = strappend("/run/systemd/sessions/", session);
+        if (!p)
+                return -ENOMEM;
+
+        r = parse_env_file(p, NEWLINE, "SERVICE", &s, NULL);
+        free(p);
+
+        if (r < 0) {
+                free(s);
+                return r;
+        }
+
+        if (isempty(s))
+                return -ENOENT;
+
+        *service = s;
+        return 0;
+}
+
 _public_ int sd_seat_get_active(const char *seat, char **session, uid_t *uid) {
         char *p, *s = NULL, *t = NULL;
         int r;
diff --git a/src/systemd/sd-login.h b/src/systemd/sd-login.h
index 00de6716b0..7d76f9a44e 100644
--- a/src/systemd/sd-login.h
+++ b/src/systemd/sd-login.h
@@ -83,6 +83,9 @@ int sd_session_get_uid(const char *session, uid_t *uid);
 /* Determine seat of session */
 int sd_session_get_seat(const char *session, char **seat);
 
+/* Determine the (PAM) service name this session was registered by. */
+int sd_session_get_service(const char *session, char **service);
+
 /* Return active session and user of seat */
 int sd_seat_get_active(const char *seat, char **session, uid_t *uid);