libbb: make parse_chown_usergroup_or_die() set unspecified uid/gid to -1

function                                             old     new   delta
parse_chown_usergroup_or_die                         102     115     +13
chown_main                                           190     175     -15
start_stop_daemon_main                              1043    1027     -16
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/2 up/down: 13/-31)            Total: -18 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

3 files changed, 6 insertions, 8 deletions

diff --git a/coreutils/chown.c b/coreutils/chown.c
index eaa1ee2a3..247aa3bf1 100644
--- a/coreutils/chown.c
+++ b/coreutils/chown.c
@@ -112,10 +112,6 @@ int chown_main(int argc UNUSED_PARAM, char **argv)
         int opt, flags;
         struct param_t param;
 
-        /* Just -1 might not work: uid_t may be unsigned long */
-        param.ugid.uid = -1L;
-        param.ugid.gid = -1L;
-
 #if ENABLE_FEATURE_CHOWN_LONG_OPTIONS
         applet_long_options = chown_longopts;
 #endif
diff --git a/debianutils/start_stop_daemon.c b/debianutils/start_stop_daemon.c
index 42f1943dd..d7c730f45 100644
--- a/debianutils/start_stop_daemon.c
+++ b/debianutils/start_stop_daemon.c
@@ -539,15 +539,15 @@ int start_stop_daemon_main(int argc UNUSED_PARAM, char **argv)
                 write_pidfile(pidfile);
         }
         if (opt & OPT_c) {
-                struct bb_uidgid_t ugid = { -1, -1 };
+                struct bb_uidgid_t ugid;
                 parse_chown_usergroup_or_die(&ugid, chuid);
-                if (ugid.uid != (uid_t) -1) {
+                if (ugid.uid != (uid_t) -1L) {
                         struct passwd *pw = xgetpwuid(ugid.uid);
-                        if (ugid.gid != (gid_t) -1)
+                        if (ugid.gid != (gid_t) -1L)
                                 pw->pw_gid = ugid.gid;
                         /* initgroups, setgid, setuid: */
                         change_identity(pw);
-                } else if (ugid.gid != (gid_t) -1) {
+                } else if (ugid.gid != (gid_t) -1L) {
                         xsetgid(ugid.gid);
                         setgroups(1, &ugid.gid);
                 }
diff --git a/libpwdgrp/uidgid_get.c b/libpwdgrp/uidgid_get.c
index eeb65191f..1199f23f9 100644
--- a/libpwdgrp/uidgid_get.c
+++ b/libpwdgrp/uidgid_get.c
@@ -90,6 +90,8 @@ void FAST_FUNC parse_chown_usergroup_or_die(struct bb_uidgid_t *u, char *user_gr
 {
         char *group;
 
+        u->uid = u->gid = (gid_t)-1L;
+
         /* Check if there is a group name */
         group = strchr(user_group, '.'); /* deprecated? */
         if (!group)