diff options
| -rw-r--r-- | elf/Makefile | 3 | ||||
| -rw-r--r-- | elf/dl-mutex.c | 19 | ||||
| -rw-r--r-- | elf/rtld.c | 18 | ||||
| -rw-r--r-- | nptl/nptl-init.c | 9 | ||||
| -rw-r--r-- | sysdeps/generic/ldsodefs.h | 25 | ||||
| -rw-r--r-- | sysdeps/nptl/dl-mutex.c | 53 | ||||
| -rw-r--r-- | sysdeps/nptl/libc-lockP.h | 17 |
7 files changed, 120 insertions, 24 deletions
diff --git a/elf/Makefile b/elf/Makefile index 4f99af626f..d3e909637a 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -66,7 +66,8 @@ elide-routines.os = $(all-dl-routines) dl-support enbl-secure dl-origin \ # interpreter and operating independent of libc. rtld-routines = rtld $(all-dl-routines) dl-sysdep dl-environ dl-minimal \ dl-error-minimal dl-conflict dl-hwcaps dl-hwcaps_split dl-hwcaps-subdirs \ - dl-usage dl-diagnostics dl-diagnostics-kernel dl-diagnostics-cpu + dl-usage dl-diagnostics dl-diagnostics-kernel dl-diagnostics-cpu \ + dl-mutex all-rtld-routines = $(rtld-routines) $(sysdep-rtld-routines) CFLAGS-dl-runtime.c += -fexceptions -fasynchronous-unwind-tables diff --git a/elf/dl-mutex.c b/elf/dl-mutex.c new file mode 100644 index 0000000000..2cd9d49c2e --- /dev/null +++ b/elf/dl-mutex.c @@ -0,0 +1,19 @@ +/* Recursive locking implementation for the dynamic loader. Generic version. + Copyright (C) 2021 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +/* The generic version initialization happpens in dl_main. */ diff --git a/elf/rtld.c b/elf/rtld.c index ad325d4c10..a359167f8a 100644 --- a/elf/rtld.c +++ b/elf/rtld.c @@ -857,6 +857,14 @@ rtld_lock_default_unlock_recursive (void *lock) __rtld_lock_default_unlock_recursive (lock); } #endif +#if PTHREAD_IN_LIBC +/* Dummy implementation. See __rtld_mutex_init. */ +static int +rtld_mutex_dummy (pthread_mutex_t *lock) +{ + return 0; +} +#endif static void @@ -1148,6 +1156,10 @@ dl_main (const ElfW(Phdr) *phdr, GL(dl_rtld_lock_recursive) = rtld_lock_default_lock_recursive; GL(dl_rtld_unlock_recursive) = rtld_lock_default_unlock_recursive; #endif +#if PTHREAD_IN_LIBC + ___rtld_mutex_lock = rtld_mutex_dummy; + ___rtld_mutex_unlock = rtld_mutex_dummy; +#endif /* The explicit initialization here is cheaper than processing the reloc in the _rtld_local definition's initializer. */ @@ -2363,6 +2375,9 @@ dl_main (const ElfW(Phdr) *phdr, loader. */ __rtld_malloc_init_real (main_map); + /* Likewise for the locking implementation. */ + __rtld_mutex_init (); + /* Mark all the objects so we know they have been already relocated. */ for (struct link_map *l = main_map; l != NULL; l = l->l_next) { @@ -2468,6 +2483,9 @@ dl_main (const ElfW(Phdr) *phdr, at this point. */ __rtld_malloc_init_real (main_map); + /* Likewise for the locking implementation. */ + __rtld_mutex_init (); + RTLD_TIMING_VAR (start); rtld_timer_start (&start); diff --git a/nptl/nptl-init.c b/nptl/nptl-init.c index fcab5a0904..2724770533 100644 --- a/nptl/nptl-init.c +++ b/nptl/nptl-init.c @@ -179,15 +179,6 @@ __pthread_initialize_minimal_internal (void) lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE); #ifdef SHARED - /* Make __rtld_lock_{,un}lock_recursive use pthread_mutex_{,un}lock, - keep the lock count from the ld.so implementation. */ - GL(dl_rtld_lock_recursive) = (void *) __pthread_mutex_lock; - GL(dl_rtld_unlock_recursive) = (void *) __pthread_mutex_unlock; - unsigned int rtld_lock_count = GL(dl_load_lock).mutex.__data.__count; - GL(dl_load_lock).mutex.__data.__count = 0; - while (rtld_lock_count-- > 0) - __pthread_mutex_lock (&GL(dl_load_lock).mutex); - GL(dl_make_stack_executable_hook) = &__make_stacks_executable; #endif diff --git a/sysdeps/generic/ldsodefs.h b/sysdeps/generic/ldsodefs.h index 1b064c5894..6d590d1335 100644 --- a/sysdeps/generic/ldsodefs.h +++ b/sysdeps/generic/ldsodefs.h @@ -403,7 +403,7 @@ struct rtld_global struct auditstate _dl_rtld_auditstate[DL_NNS]; #endif -#if defined SHARED && defined _LIBC_REENTRANT \ +#if !PTHREAD_IN_LIBC && defined SHARED \ && defined __rtld_lock_default_lock_recursive EXTERN void (*_dl_rtld_lock_recursive) (void *); EXTERN void (*_dl_rtld_unlock_recursive) (void *); @@ -1318,6 +1318,29 @@ link_map_audit_state (struct link_map *l, size_t index) } #endif /* SHARED */ +#if PTHREAD_IN_LIBC && defined SHARED +/* Recursive locking implementation for use within the dynamic loader. + Used to define the __rtld_lock_lock_recursive and + __rtld_lock_unlock_recursive via <libc-lock.h>. Initialized to a + no-op dummy implementation early. Similar + to GL (dl_rtld_lock_recursive) and GL (dl_rtld_unlock_recursive) + in !PTHREAD_IN_LIBC builds. */ +extern int (*___rtld_mutex_lock) (pthread_mutex_t *) attribute_hidden; +extern int (*___rtld_mutex_unlock) (pthread_mutex_t *lock) attribute_hidden; + +/* Called after libc has been loaded, but before RELRO is activated. + Used to initialize the function pointers to the actual + implementations. */ +void __rtld_mutex_init (void) attribute_hidden; +#else /* !PTHREAD_IN_LIBC */ +static inline void +__rtld_mutex_init (void) +{ + /* The initialization happens later (!PTHREAD_IN_LIBC) or is not + needed at all (!SHARED). */ +} +#endif /* !PTHREAD_IN_LIBC */ + #if THREAD_GSCOPE_IN_TCB void __thread_gscope_wait (void) attribute_hidden; # define THREAD_GSCOPE_WAIT() __thread_gscope_wait () diff --git a/sysdeps/nptl/dl-mutex.c b/sysdeps/nptl/dl-mutex.c new file mode 100644 index 0000000000..08b71dc21b --- /dev/null +++ b/sysdeps/nptl/dl-mutex.c @@ -0,0 +1,53 @@ +/* Recursive locking implementation for the dynamic loader. NPTL version. + Copyright (C) 2021 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +/* Use the mutex implementation in libc (assuming PTHREAD_IN_LIBC). */ + +#include <assert.h> +#include <first-versions.h> +#include <ldsodefs.h> + +__typeof (pthread_mutex_lock) *___rtld_mutex_lock attribute_relro; +__typeof (pthread_mutex_unlock) *___rtld_mutex_unlock attribute_relro; + +void +__rtld_mutex_init (void) +{ + /* There is an implicit assumption here that the lock counters are + zero and this function is called while nothing is locked. For + early initialization of the mutex functions this is true because + it happens directly in dl_main in elf/rtld.c, and not some ELF + constructor while holding loader locks. */ + + struct link_map *libc_map = GL (dl_ns)[LM_ID_BASE].libc_map; + + const ElfW(Sym) *sym + = _dl_lookup_direct (libc_map, "pthread_mutex_lock", + 0x4f152227, /* dl_new_hash output. */ + FIRST_VERSION_libc_pthread_mutex_lock_STRING, + FIRST_VERSION_libc_pthread_mutex_lock_HASH); + assert (sym != NULL); + ___rtld_mutex_lock = DL_SYMBOL_ADDRESS (libc_map, sym); + + sym = _dl_lookup_direct (libc_map, "pthread_mutex_unlock", + 0x7dd7aaaa, /* dl_new_hash output. */ + FIRST_VERSION_libc_pthread_mutex_unlock_STRING, + FIRST_VERSION_libc_pthread_mutex_unlock_HASH); + assert (sym != NULL); + ___rtld_mutex_unlock = DL_SYMBOL_ADDRESS (libc_map, sym); +} diff --git a/sysdeps/nptl/libc-lockP.h b/sysdeps/nptl/libc-lockP.h index ae9691d40e..ec7b02bbdd 100644 --- a/sysdeps/nptl/libc-lockP.h +++ b/sysdeps/nptl/libc-lockP.h @@ -151,9 +151,6 @@ _Static_assert (LLL_LOCK_INITIALIZER == 0, "LLL_LOCK_INITIALIZER != 0"); __libc_maybe_call (__pthread_mutex_trylock, (&(NAME)), 0) #endif -#define __rtld_lock_trylock_recursive(NAME) \ - __libc_maybe_call (__pthread_mutex_trylock, (&(NAME).mutex), 0) - /* Unlock the named lock variable. */ #if IS_IN (libc) || IS_IN (libpthread) # define __libc_lock_unlock(NAME) \ @@ -163,19 +160,13 @@ _Static_assert (LLL_LOCK_INITIALIZER == 0, "LLL_LOCK_INITIALIZER != 0"); #endif #define __libc_rwlock_unlock(NAME) __pthread_rwlock_unlock (&(NAME)) -#ifdef SHARED -# define __rtld_lock_default_lock_recursive(lock) \ - ++((pthread_mutex_t *)(lock))->__data.__count; - -# define __rtld_lock_default_unlock_recursive(lock) \ - --((pthread_mutex_t *)(lock))->__data.__count; - +#if IS_IN (rtld) # define __rtld_lock_lock_recursive(NAME) \ - GL(dl_rtld_lock_recursive) (&(NAME).mutex) + ___rtld_mutex_lock (&(NAME).mutex) # define __rtld_lock_unlock_recursive(NAME) \ - GL(dl_rtld_unlock_recursive) (&(NAME).mutex) -#else + ___rtld_mutex_unlock (&(NAME).mutex) +#else /* Not in the dynamic loader. */ # define __rtld_lock_lock_recursive(NAME) \ __pthread_mutex_lock (&(NAME).mutex) |