96b060730

Denys Vlasenko

2024-10-07

SUCCESS Duration: 155s

Subject

ash: cache more of uid/gid syscalls

No binary (build failed)

Architecture: x86_64-linux-gnu Compiler: gcc (Ubuntu 11.4.0-1ubuntu1~22.04.3) 11.4.0

—

(log yok)

coreutils/test.c+7 -4

@@ -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);

include/libbb.h+4 -2

@@ -1206,11 +1206,13 @@ gid_t bb_getgroups(int ngroups, gid_t *group_array) FAST_FUNC;
	* getgroups() is cached in supplementary_array[], to make successive calls faster.
	*/
	struct cached_groupinfo {
-	//TODO? gid_t egid;
+	uid_t euid;
+	gid_t egid;
	int ngroups;
	gid_t *supplementary_array;
	};
-	//TODO? int FAST_FUNC get_cached_egid(gid_t *egid);
+	uid_t FAST_FUNC get_cached_euid(uid_t *euid);
+	gid_t FAST_FUNC get_cached_egid(gid_t *egid);
	int FAST_FUNC is_in_supplementary_groups(struct cached_groupinfo *groupinfo, gid_t gid);

	#if ENABLE_FEATURE_UTMP

libbb/bb_getgroups.c+14 -0

@@ -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)
	{

shell/ash.c+5 -4

@@ -536,6 +536,8 @@ extern struct globals_misc *BB_GLOBAL_CONST ash_ptr_to_globals_misc;
	curdir = nullstr; \
	physdir = nullstr; \
	trap_ptr = trap; \
+	groupinfo.euid = -1; \
+	groupinfo.egid = -1; \
	} while (0)


@@ -2319,7 +2321,7 @@ initvar(void)
	#if ENABLE_FEATURE_EDITING && ENABLE_FEATURE_EDITING_FANCY_PROMPT
	vps1.var_text = "PS1=\\w \\$ ";
	#else
-	if (!geteuid())
+	if (!get_cached_euid(&groupinfo.euid));
	vps1.var_text = "PS1=# ";
	#endif
	vp = varinit;
@@ -13809,14 +13811,13 @@ static int test_exec(/const char fullname,/ struct stat statb)

	/* Executability depends on our euid/egid/supplementary groups */
	stmode = S_IXOTH;
-	euid = geteuid();
-	//TODO: cache euid?
+	euid = get_cached_euid(&groupinfo.euid);
	if (euid == 0)
	/* for root user, any X bit is good enough */
	stmode = ANY_IX;
	else if (statb->st_uid == euid)
	stmode = S_IXUSR;
-	else if (statb->st_gid == getegid())
+	else if (statb->st_gid == get_cached_egid(&groupinfo.egid))
	stmode = S_IXGRP;
	else if (is_in_supplementary_groups(&groupinfo, statb->st_gid))
	stmode = S_IXGRP;