1 files changed, 36 insertions, 0 deletions

diff --git a/libpwdgrp/uidgid_get.c b/libpwdgrp/uidgid_get.c
index 69c228e16..f10b40654 100644
--- a/libpwdgrp/uidgid_get.c
+++ b/libpwdgrp/uidgid_get.c
@@ -27,6 +27,7 @@ ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
 #include "busybox.h"
 
+/* Always sets uid and gid */
 int get_uidgid(struct bb_uidgid_t *u, const char *ug, int numeric_ok)
 {
         struct passwd *pwd;
@@ -53,6 +54,7 @@ int get_uidgid(struct bb_uidgid_t *u, const char *ug, int numeric_ok)
                         goto skip;
                 }
         }
+        /* Either it is not numeric, or caller disallows numeric username */
         pwd = getpwnam(user);
         if (!pwd)
                 return 0;
@@ -75,6 +77,40 @@ int get_uidgid(struct bb_uidgid_t *u, const char *ug, int numeric_ok)
         return 1;
 }
 
+/* chown-like:
+ * "user" sets uid only,
+ * ":group" sets gid only
+ * "user:" sets uid and gid (to user's primary group id)
+ * "user:group" sets uid and gid
+ * ('unset' uid or gid is actually set to -1)
+ */
+void parse_chown_usergroup_or_die(struct bb_uidgid_t *u, char *user_group)
+{
+        char *group;
+
+        u->uid = -1;
+        u->gid = -1;
+
+        /* Check if there is a group name */
+        group = strchr(user_group, '.'); /* deprecated? */
+        if (!group)
+                group = strchr(user_group, ':');
+        else
+                *group = ':'; /* replace '.' with ':' */
+
+        /* Parse "user[:[group]]" */
+        if (!group) { /* "user" */
+                u->uid = get_ug_id(user_group, xuname2uid);
+        } else if (group == user_group) { /* ":group" */
+                u->gid = get_ug_id(group + 1, xgroup2gid);
+        } else {
+                if (!group[1]) /* "user:" */
+                        *group = '\0';
+                if (!get_uidgid(u, user_group, 1))
+                        bb_error_msg_and_die("unknown user/group %s", user_group);
+        }
+}
+
 #if 0
 #include <stdio.h>
 int main()