util: introduce get_process_gid()

src/shared/util.c

@@ -1108,7 +1108,7 @@ int get_process_exe(pid_t pid, char **name) {
         return r;
 }
 
-int get_process_uid(pid_t pid, uid_t *uid) {
+static int get_process_id(pid_t pid, const char *field, uid_t *uid) {
         char *p;
         FILE *f;
         int r;
@@ -1140,8 +1140,8 @@ int get_process_uid(pid_t pid, uid_t *uid) {
 
                 l = strstrip(line);
 
-                if (startswith(l, "Uid:")) {
-                        l += 4;
+                if (startswith(l, field)) {
+                        l += strlen(field);
                         l += strspn(l, WHITESPACE);
 
                         l[strcspn(l, WHITESPACE)] = 0;
@@ -1159,6 +1159,14 @@ finish:
         return r;
 }
 
+int get_process_uid(pid_t pid, uid_t *uid) {
+        return get_process_id(pid, "Uid:", uid);
+}
+
+int get_process_gid(pid_t pid, gid_t *gid) {
+        return get_process_id(pid, "Gid:", gid);
+}
+
 char *strnappend(const char *s, const char *suffix, size_t b) {
         size_t a;
         char *r;

src/shared/util.h

@@ -246,6 +246,7 @@ int get_process_comm(pid_t pid, char **name);
 int get_process_cmdline(pid_t pid, size_t max_length, bool comm_fallback, char **line);
 int get_process_exe(pid_t pid, char **name);
 int get_process_uid(pid_t pid, uid_t *uid);
+int get_process_gid(pid_t pid, gid_t *gid);
 
 char hexchar(int x);
 int unhexchar(char c);