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ash: cache more of uid/gid syscalls

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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>
This commit is contained in:
Denys Vlasenko 2024-10-07 07:28:44 +02:00
parent d26e958725
commit 96b0607302
4 changed files with 30 additions and 10 deletions
Download patch file Download diff file Expand all files Collapse all files

14
libbb/bb_getgroups.c
View file

@ -46,6 +46,20 @@ gid_t* FAST_FUNC bb_getgroups(int *ngroups, gid_t *group_array)
return group_array;
}
uid_t FAST_FUNC get_cached_euid(uid_t *euid)
{
if (*euid == (uid_t)-1)
*euid = geteuid();
return *euid;
}
gid_t FAST_FUNC get_cached_egid(gid_t *egid)
{
if (*egid == (gid_t)-1)
*egid = getegid();
return *egid;
}
/* Return non-zero if GID is in our supplementary group list. */
int FAST_FUNC is_in_supplementary_groups(struct cached_groupinfo *groupinfo, gid_t gid)
{