login: introduce sd_pid_get_service()

3 files changed, 36 insertions, 0 deletions

diff --git a/src/login/libsystemd-login.sym b/src/login/libsystemd-login.sym
index 0d51fa76e7..bac46f4064 100644
--- a/src/login/libsystemd-login.sym
+++ b/src/login/libsystemd-login.sym
@@ -33,3 +33,8 @@ global:
 local:
         *;
 };
+
+LIBSYSTEMD_LOGIN_38 {
+global:
+        sd_pid_get_service;
+} LIBSYSTEMD_LOGIN_31;
diff --git a/src/login/sd-login.c b/src/login/sd-login.c
index a0a56c4952..1d4368187f 100644
--- a/src/login/sd-login.c
+++ b/src/login/sd-login.c
@@ -121,6 +121,33 @@ _public_ int sd_pid_get_session(pid_t pid, char **session) {
         return 0;
 }
 
+_public_ int sd_pid_get_service(pid_t pid, char **service) {
+        int r;
+        char *cgroup, *p;
+
+        if (!service)
+                return -EINVAL;
+
+        r = pid_get_cgroup(pid, NULL, &cgroup);
+        if (r < 0)
+                return r;
+
+        if (!startswith(cgroup, "/system/")) {
+                free(cgroup);
+                return -ENOENT;
+        }
+
+        p = cgroup + 8;
+        p = strndup(p, strcspn(p, "/"));
+        free(cgroup);
+
+        if (!p)
+                return -ENOMEM;
+
+        *service = p;
+        return 0;
+}
+
 _public_ int sd_pid_get_owner_uid(pid_t pid, uid_t *uid) {
         int r;
         char *root, *cgroup, *p, *cc;
diff --git a/src/login/sd-login.h b/src/login/sd-login.h
index 0cb0bf06bb..1d8a55e906 100644
--- a/src/login/sd-login.h
+++ b/src/login/sd-login.h
@@ -53,6 +53,10 @@ int sd_pid_get_session(pid_t pid, char **session);
  * return an error for system processes. */
 int sd_pid_get_owner_uid(pid_t pid, uid_t *uid);
 
+/* Get service name from PID. This will return an error for
+ * non-service processes. */
+int sd_pid_get_service(pid_t, char **service);
+
 /* Get state from uid. Possible states: offline, lingering, online, active */
 int sd_uid_get_state(uid_t uid, char**state);