Implement support for ELF filters in rtld. Both normal and auxillary

filters are implemented.

Filtees are loaded on demand, unless LD_LOADFLTR environment variable
is set or -z loadfltr was specified during the linking. This forces
rtld to upgrade read-locked rtld_bind_lock to write lock when it
encounters an object with filter during symbol lookup.

Consolidate common arguments of the symbol lookup functions in the
SymLook structure.  Track the state of the rtld locks in the
RtldLockState structure. Pass local RtldLockState through the rtld
symbol lookup calls to allow lock upgrades.

Reviewed by:	kan
Tested by:	Mykola Dzham <i levsha me>, nwhitehorn (powerpc)

1 files changed, 12 insertions, 4 deletions

diff --git a/libexec/rtld-elf/rtld_lock.h b/libexec/rtld-elf/rtld_lock.h
index 6c04e3b96e37..fa63787d52ac 100644
--- a/libexec/rtld-elf/rtld_lock.h
+++ b/libexec/rtld-elf/rtld_lock.h
@@ -57,10 +57,18 @@ extern rtld_lock_t	rtld_bind_lock;
 extern rtld_lock_t	rtld_libc_lock;
 extern rtld_lock_t	rtld_phdr_lock;
 
-int	rlock_acquire(rtld_lock_t);
-int 	wlock_acquire(rtld_lock_t);
-void	rlock_release(rtld_lock_t, int);
-void	wlock_release(rtld_lock_t, int);
+#define	RTLD_LOCK_UNLOCKED	0
+#define	RTLD_LOCK_RLOCKED	1
+#define	RTLD_LOCK_WLOCKED	2
+
+struct Struct_RtldLockState;
+typedef struct Struct_RtldLockState RtldLockState;
+
+void	rlock_acquire(rtld_lock_t, RtldLockState *);
+void 	wlock_acquire(rtld_lock_t, RtldLockState *);
+void	lock_release(rtld_lock_t, RtldLockState *);
+void	lock_upgrade(rtld_lock_t, RtldLockState *);
+void	lock_restart_for_upgrade(RtldLockState *);
 
 #endif	/* IN_RTLD */