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nptl: Use internal low-level lock type for !IS_IN (libc)

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This avoids an ABI hazard (types changing between different modules
of glibc) without introducing linknamespace issues. In particular,
NSS modules now call __lll_lock_wait_private@@GLIBC_PRIVATE to wait
on internal locks (the unlock path is inlined and performs a direct
system call).

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
This commit is contained in:
Florian Weimer 2021-07-07 08:40:41 +02:00
parent 83e55c982f
commit 1f9c804fbd
1 changed files with 5 additions and 46 deletions
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51
sysdeps/nptl/libc-lockP.h
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@ -33,18 +33,8 @@
#include <lowlevellock.h>
#include <tls.h>
#if IS_IN (libpthread)
/* This gets us the declarations of the __pthread_* internal names,
and hidden_proto for them. */
# include <pthreadP.h>
#endif
/* Mutex type. */
#if !IS_IN (libc) && !IS_IN (libpthread)
typedef pthread_mutex_t __libc_lock_t;
#else
typedef int __libc_lock_t;
#endif
typedef struct { pthread_mutex_t mutex; } __rtld_lock_recursive_t;
typedef pthread_rwlock_t __libc_rwlock_t;
@ -108,56 +98,25 @@ _Static_assert (LLL_LOCK_INITIALIZER == 0, "LLL_LOCK_INITIALIZER != 0");
/* Initialize the named lock variable, leaving it in a consistent, unlocked
state. */
#if IS_IN (libc) || IS_IN (libpthread)
# define __libc_lock_init(NAME) \
((void) ((NAME) = LLL_LOCK_INITIALIZER))
#else
# define __libc_lock_init(NAME) __pthread_mutex_init (&(NAME))
#endif
#define __libc_lock_init(NAME) ((void) ((NAME) = LLL_LOCK_INITIALIZER))
#define __libc_rwlock_init(NAME) __pthread_rwlock_init (&(NAME), NULL)
/* Finalize the named lock variable, which must be locked. It cannot be
used again until __libc_lock_init is called again on it. This must be
called on a lock variable before the containing storage is reused. */
#if IS_IN (libc) || IS_IN (libpthread)
# define __libc_lock_fini(NAME) ((void) 0)
#else
# define __libc_lock_fini(NAME) __pthread_mutex_destroy (&(NAME))
#endif
#define __libc_lock_fini(NAME) ((void) 0)
#define __libc_rwlock_fini(NAME) ((void) 0)
/* Lock the named lock variable. */
#if IS_IN (libc) || IS_IN (libpthread)
# ifndef __libc_lock_lock
# define __libc_lock_lock(NAME) \
({ lll_lock (NAME, LLL_PRIVATE); 0; })
# endif
#else
# undef __libc_lock_lock
# define __libc_lock_lock(NAME) __pthread_mutex_lock (&(NAME))
#endif
#define __libc_lock_lock(NAME) ({ lll_lock (NAME, LLL_PRIVATE); 0; })
#define __libc_rwlock_rdlock(NAME) __pthread_rwlock_rdlock (&(NAME))
#define __libc_rwlock_wrlock(NAME) __pthread_rwlock_wrlock (&(NAME))
/* Try to lock the named lock variable. */
#if IS_IN (libc) || IS_IN (libpthread)
# ifndef __libc_lock_trylock
# define __libc_lock_trylock(NAME) \
lll_trylock (NAME)
# endif
#else
# undef __libc_lock_trylock
# define __libc_lock_trylock(NAME) \
__libc_maybe_call (__pthread_mutex_trylock, (&(NAME)), 0)
#endif
#define __libc_lock_trylock(NAME) lll_trylock (NAME)
/* Unlock the named lock variable. */
#if IS_IN (libc) || IS_IN (libpthread)
# define __libc_lock_unlock(NAME) \
lll_unlock (NAME, LLL_PRIVATE)
#else
# define __libc_lock_unlock(NAME) __pthread_mutex_unlock (&(NAME))
#endif
#define __libc_lock_unlock(NAME) lll_unlock (NAME, LLL_PRIVATE)
#define __libc_rwlock_unlock(NAME) __pthread_rwlock_unlock (&(NAME))
#if IS_IN (rtld)