ash: cache more of uid/gid syscalls

Testcase:
setuidgid 1:1 strace ash -c 'test -x TODO; test -x TODO; echo $?'
should show that second "test -x" does not query ids again.

function                                             old     new   delta
ash_main                                            1236    1256     +20
get_cached_euid                                        -      19     +19
get_cached_egid                                        -      19     +19
test_main                                             56      72     +16
test_exec                                            119     135     +16
is_in_supplementary_groups                            52      57      +5
nexpr                                                718     702     -16
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 4/1 up/down: 95/-16)             Total: 79 bytes

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

1 files changed, 7 insertions, 4 deletions

diff --git a/coreutils/test.c b/coreutils/test.c
index ad777953f..6085d6663 100644
--- a/coreutils/test.c
+++ b/coreutils/test.c
@@ -638,7 +638,7 @@ static int binop(void)
 static int is_a_group_member(gid_t gid)
 {
         /* Short-circuit if possible, maybe saving a call to getgroups(). */
-        if (gid == getgid() || gid == getegid())
+        if (gid == get_cached_egid(&groupinfo->egid))
                 return 1;
 
         return is_in_supplementary_groups(groupinfo, gid);
@@ -656,15 +656,16 @@ static int test_st_mode(struct stat *st, int mode)
 
 //TODO  if (mode == X_OK) {
 //              /* Do we already know with no extra syscalls? */
-//              if (!S_ISREG(st->st_mode))
-//                      return 0; /* not a regular file */
+//              //if (!S_ISREG(st->st_mode))
+//              //      return 0; /* not a regular file */
+//              // ^^^ bash does not check this
 //              if ((st->st_mode & ANY_IX) == 0)
 //                      return 0; /* no one can execute */
 //              if ((st->st_mode & ANY_IX) == ANY_IX)
 //                      return 1; /* anyone can execute */
 //      }
 
-        euid = geteuid();
+        euid = get_cached_euid(&groupinfo->euid);
         if (euid == 0) {
                 /* Root can read or write any file. */
                 if (mode != X_OK)
@@ -1019,6 +1020,8 @@ int test_main(int argc, char **argv)
         struct cached_groupinfo info;
         int r;
 
+        info.euid = -1;
+        info.egid = -1;
         info.ngroups = 0;
         info.supplementary_array = NULL;
         r = test_main2(&info, argc, argv);