tar: cache [ug]id->username/groupname mappings. Cuts down amount

of open/read/close of /etc/passwd and /etc/group
dramatically (we were rereading those for each untarred file!!!)

1 files changed, 3 insertions, 6 deletions

diff --git a/archival/tar.c b/archival/tar.c
index 99c4adb6a..51d34ea19 100644
--- a/archival/tar.c
+++ b/archival/tar.c
@@ -211,12 +211,9 @@ static int writeTarHeader(struct TarBallInfo *tbInfo,
         putOctal(header.mtime, sizeof(header.mtime), statbuf->st_mtime);
         strcpy(header.magic, "ustar  ");
 
-        /* Enter the user and group names (default to root if it fails) */
-//cache!!!
-        if (bb_getpwuid(header.uname, statbuf->st_uid, sizeof(header.uname)) == NULL)
-                strcpy(header.uname, "root");
-        if (bb_getgrgid(header.gname, statbuf->st_gid, sizeof(header.gname)) == NULL)
-                strcpy(header.gname, "root");
+        /* Enter the user and group names */
+        safe_strncpy(header.uname, get_cached_username(statbuf->st_uid), sizeof(header.uname));
+        safe_strncpy(header.gname, get_cached_groupname(statbuf->st_gid), sizeof(header.gname));
 
         if (tbInfo->hlInfo) {
                 /* This is a hard link */