glibc/nptl/nptl-init.c

474 lines
17 KiB
C

/* Copyright (C) 2002-2014 Free Software Foundation, Inc.
This file is part of the GNU C Library.
Contributed by Ulrich Drepper <drepper@redhat.com>, 2002.
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
<http://www.gnu.org/licenses/>. */
#include <assert.h>
#include <errno.h>
#include <limits.h>
#include <signal.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/param.h>
#include <sys/resource.h>
#include <pthreadP.h>
#include <atomic.h>
#include <ldsodefs.h>
#include <tls.h>
#include <list.h>
#include <fork.h>
#include <version.h>
#include <shlib-compat.h>
#include <smp.h>
#include <lowlevellock.h>
#include <kernel-features.h>
/* Size and alignment of static TLS block. */
size_t __static_tls_size;
size_t __static_tls_align_m1;
#ifndef __ASSUME_SET_ROBUST_LIST
/* Negative if we do not have the system call and we can use it. */
int __set_robust_list_avail;
# define set_robust_list_not_avail() \
__set_robust_list_avail = -1
#else
# define set_robust_list_not_avail() do { } while (0)
#endif
#ifndef __ASSUME_FUTEX_CLOCK_REALTIME
/* Nonzero if we do not have FUTEX_CLOCK_REALTIME. */
int __have_futex_clock_realtime;
# define __set_futex_clock_realtime() \
__have_futex_clock_realtime = 1
#else
#define __set_futex_clock_realtime() do { } while (0)
#endif
/* Version of the library, used in libthread_db to detect mismatches. */
static const char nptl_version[] __attribute_used__ = VERSION;
#ifndef SHARED
extern void __libc_setup_tls (size_t tcbsize, size_t tcbalign);
#endif
#ifdef SHARED
static
#else
extern
#endif
void __nptl_set_robust (struct pthread *);
#ifdef SHARED
static void nptl_freeres (void);
static const struct pthread_functions pthread_functions =
{
.ptr_pthread_attr_destroy = __pthread_attr_destroy,
# if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_1)
.ptr___pthread_attr_init_2_0 = __pthread_attr_init_2_0,
# endif
.ptr___pthread_attr_init_2_1 = __pthread_attr_init_2_1,
.ptr_pthread_attr_getdetachstate = __pthread_attr_getdetachstate,
.ptr_pthread_attr_setdetachstate = __pthread_attr_setdetachstate,
.ptr_pthread_attr_getinheritsched = __pthread_attr_getinheritsched,
.ptr_pthread_attr_setinheritsched = __pthread_attr_setinheritsched,
.ptr_pthread_attr_getschedparam = __pthread_attr_getschedparam,
.ptr_pthread_attr_setschedparam = __pthread_attr_setschedparam,
.ptr_pthread_attr_getschedpolicy = __pthread_attr_getschedpolicy,
.ptr_pthread_attr_setschedpolicy = __pthread_attr_setschedpolicy,
.ptr_pthread_attr_getscope = __pthread_attr_getscope,
.ptr_pthread_attr_setscope = __pthread_attr_setscope,
.ptr_pthread_condattr_destroy = __pthread_condattr_destroy,
.ptr_pthread_condattr_init = __pthread_condattr_init,
.ptr___pthread_cond_broadcast = __pthread_cond_broadcast,
.ptr___pthread_cond_destroy = __pthread_cond_destroy,
.ptr___pthread_cond_init = __pthread_cond_init,
.ptr___pthread_cond_signal = __pthread_cond_signal,
.ptr___pthread_cond_wait = __pthread_cond_wait,
.ptr___pthread_cond_timedwait = __pthread_cond_timedwait,
# if SHLIB_COMPAT(libpthread, GLIBC_2_0, GLIBC_2_3_2)
.ptr___pthread_cond_broadcast_2_0 = __pthread_cond_broadcast_2_0,
.ptr___pthread_cond_destroy_2_0 = __pthread_cond_destroy_2_0,
.ptr___pthread_cond_init_2_0 = __pthread_cond_init_2_0,
.ptr___pthread_cond_signal_2_0 = __pthread_cond_signal_2_0,
.ptr___pthread_cond_wait_2_0 = __pthread_cond_wait_2_0,
.ptr___pthread_cond_timedwait_2_0 = __pthread_cond_timedwait_2_0,
# endif
.ptr_pthread_equal = __pthread_equal,
.ptr___pthread_exit = __pthread_exit,
.ptr_pthread_getschedparam = __pthread_getschedparam,
.ptr_pthread_setschedparam = __pthread_setschedparam,
.ptr_pthread_mutex_destroy = __pthread_mutex_destroy,
.ptr_pthread_mutex_init = __pthread_mutex_init,
.ptr_pthread_mutex_lock = __pthread_mutex_lock,
.ptr_pthread_mutex_unlock = __pthread_mutex_unlock,
.ptr_pthread_self = __pthread_self,
.ptr_pthread_setcancelstate = __pthread_setcancelstate,
.ptr_pthread_setcanceltype = __pthread_setcanceltype,
.ptr___pthread_cleanup_upto = __pthread_cleanup_upto,
.ptr___pthread_once = __pthread_once,
.ptr___pthread_rwlock_rdlock = __pthread_rwlock_rdlock,
.ptr___pthread_rwlock_wrlock = __pthread_rwlock_wrlock,
.ptr___pthread_rwlock_unlock = __pthread_rwlock_unlock,
.ptr___pthread_key_create = __pthread_key_create,
.ptr___pthread_getspecific = __pthread_getspecific,
.ptr___pthread_setspecific = __pthread_setspecific,
.ptr__pthread_cleanup_push_defer = __pthread_cleanup_push_defer,
.ptr__pthread_cleanup_pop_restore = __pthread_cleanup_pop_restore,
.ptr_nthreads = &__nptl_nthreads,
.ptr___pthread_unwind = &__pthread_unwind,
.ptr__nptl_deallocate_tsd = __nptl_deallocate_tsd,
.ptr__nptl_setxid = __nptl_setxid,
/* For now only the stack cache needs to be freed. */
.ptr_freeres = nptl_freeres,
.ptr_set_robust = __nptl_set_robust
};
# define ptr_pthread_functions &pthread_functions
#else
# define ptr_pthread_functions NULL
#endif
#ifdef SHARED
/* This function is called indirectly from the freeres code in libc. */
static void
__libc_freeres_fn_section
nptl_freeres (void)
{
__unwind_freeres ();
__free_stacks (0);
}
static
#endif
void
__nptl_set_robust (struct pthread *self)
{
INTERNAL_SYSCALL_DECL (err);
INTERNAL_SYSCALL (set_robust_list, err, 2, &self->robust_head,
sizeof (struct robust_list_head));
}
/* For asynchronous cancellation we use a signal. This is the handler. */
static void
sigcancel_handler (int sig, siginfo_t *si, void *ctx)
{
/* Determine the process ID. It might be negative if the thread is
in the middle of a fork() call. */
pid_t pid = THREAD_GETMEM (THREAD_SELF, pid);
if (__builtin_expect (pid < 0, 0))
pid = -pid;
/* Safety check. It would be possible to call this function for
other signals and send a signal from another process. This is not
correct and might even be a security problem. Try to catch as
many incorrect invocations as possible. */
if (sig != SIGCANCEL
|| si->si_pid != pid
|| si->si_code != SI_TKILL)
return;
struct pthread *self = THREAD_SELF;
int oldval = THREAD_GETMEM (self, cancelhandling);
while (1)
{
/* We are canceled now. When canceled by another thread this flag
is already set but if the signal is directly send (internally or
from another process) is has to be done here. */
int newval = oldval | CANCELING_BITMASK | CANCELED_BITMASK;
if (oldval == newval || (oldval & EXITING_BITMASK) != 0)
/* Already canceled or exiting. */
break;
int curval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling, newval,
oldval);
if (curval == oldval)
{
/* Set the return value. */
THREAD_SETMEM (self, result, PTHREAD_CANCELED);
/* Make sure asynchronous cancellation is still enabled. */
if ((newval & CANCELTYPE_BITMASK) != 0)
/* Run the registered destructors and terminate the thread. */
__do_cancel ();
break;
}
oldval = curval;
}
}
struct xid_command *__xidcmd attribute_hidden;
/* We use the SIGSETXID signal in the setuid, setgid, etc. implementations to
tell each thread to call the respective setxid syscall on itself. This is
the handler. */
static void
sighandler_setxid (int sig, siginfo_t *si, void *ctx)
{
/* Determine the process ID. It might be negative if the thread is
in the middle of a fork() call. */
pid_t pid = THREAD_GETMEM (THREAD_SELF, pid);
if (__builtin_expect (pid < 0, 0))
pid = -pid;
/* Safety check. It would be possible to call this function for
other signals and send a signal from another process. This is not
correct and might even be a security problem. Try to catch as
many incorrect invocations as possible. */
if (sig != SIGSETXID
|| si->si_pid != pid
|| si->si_code != SI_TKILL)
return;
INTERNAL_SYSCALL_DECL (err);
INTERNAL_SYSCALL_NCS (__xidcmd->syscall_no, err, 3, __xidcmd->id[0],
__xidcmd->id[1], __xidcmd->id[2]);
/* Reset the SETXID flag. */
struct pthread *self = THREAD_SELF;
int flags, newval;
do
{
flags = THREAD_GETMEM (self, cancelhandling);
newval = THREAD_ATOMIC_CMPXCHG_VAL (self, cancelhandling,
flags & ~SETXID_BITMASK, flags);
}
while (flags != newval);
/* And release the futex. */
self->setxid_futex = 1;
lll_futex_wake (&self->setxid_futex, 1, LLL_PRIVATE);
if (atomic_decrement_val (&__xidcmd->cntr) == 0)
lll_futex_wake (&__xidcmd->cntr, 1, LLL_PRIVATE);
}
/* When using __thread for this, we do it in libc so as not
to give libpthread its own TLS segment just for this. */
extern void **__libc_dl_error_tsd (void) __attribute__ ((const));
/* This can be set by the debugger before initialization is complete. */
static bool __nptl_initial_report_events __attribute_used__;
void
__pthread_initialize_minimal_internal (void)
{
#ifndef SHARED
/* Unlike in the dynamically linked case the dynamic linker has not
taken care of initializing the TLS data structures. */
__libc_setup_tls (TLS_TCB_SIZE, TLS_TCB_ALIGN);
/* We must prevent gcc from being clever and move any of the
following code ahead of the __libc_setup_tls call. This function
will initialize the thread register which is subsequently
used. */
__asm __volatile ("");
#endif
/* Minimal initialization of the thread descriptor. */
struct pthread *pd = THREAD_SELF;
INTERNAL_SYSCALL_DECL (err);
pd->pid = pd->tid = INTERNAL_SYSCALL (set_tid_address, err, 1, &pd->tid);
THREAD_SETMEM (pd, specific[0], &pd->specific_1stblock[0]);
THREAD_SETMEM (pd, user_stack, true);
if (LLL_LOCK_INITIALIZER != 0)
THREAD_SETMEM (pd, lock, LLL_LOCK_INITIALIZER);
#if HP_TIMING_AVAIL
THREAD_SETMEM (pd, cpuclock_offset, GL(dl_cpuclock_offset));
#endif
/* Initialize the robust mutex data. */
#ifdef __PTHREAD_MUTEX_HAVE_PREV
pd->robust_prev = &pd->robust_head;
#endif
pd->robust_head.list = &pd->robust_head;
#ifdef __NR_set_robust_list
pd->robust_head.futex_offset = (offsetof (pthread_mutex_t, __data.__lock)
- offsetof (pthread_mutex_t,
__data.__list.__next));
int res = INTERNAL_SYSCALL (set_robust_list, err, 2, &pd->robust_head,
sizeof (struct robust_list_head));
if (INTERNAL_SYSCALL_ERROR_P (res, err))
#endif
set_robust_list_not_avail ();
#ifndef __ASSUME_PRIVATE_FUTEX
/* Private futexes are always used (at least internally) so that
doing the test once this early is beneficial. */
{
int word = 0;
word = INTERNAL_SYSCALL (futex, err, 3, &word,
FUTEX_WAKE | FUTEX_PRIVATE_FLAG, 1);
if (!INTERNAL_SYSCALL_ERROR_P (word, err))
THREAD_SETMEM (pd, header.private_futex, FUTEX_PRIVATE_FLAG);
}
/* Private futexes have been introduced earlier than the
FUTEX_CLOCK_REALTIME flag. We don't have to run the test if we
know the former are not supported. This also means we know the
kernel will return ENOSYS for unknown operations. */
if (THREAD_GETMEM (pd, header.private_futex) != 0)
#endif
#ifndef __ASSUME_FUTEX_CLOCK_REALTIME
{
int word = 0;
/* NB: the syscall actually takes six parameters. The last is the
bit mask. But since we will not actually wait at all the value
is irrelevant. Given that passing six parameters is difficult
on some architectures we just pass whatever random value the
calling convention calls for to the kernel. It causes no harm. */
word = INTERNAL_SYSCALL (futex, err, 5, &word,
FUTEX_WAIT_BITSET | FUTEX_CLOCK_REALTIME
| FUTEX_PRIVATE_FLAG, 1, NULL, 0);
assert (INTERNAL_SYSCALL_ERROR_P (word, err));
if (INTERNAL_SYSCALL_ERRNO (word, err) != ENOSYS)
__set_futex_clock_realtime ();
}
#endif
/* Set initial thread's stack block from 0 up to __libc_stack_end.
It will be bigger than it actually is, but for unwind.c/pt-longjmp.c
purposes this is good enough. */
THREAD_SETMEM (pd, stackblock_size, (size_t) __libc_stack_end);
/* Initialize the list of all running threads with the main thread. */
INIT_LIST_HEAD (&__stack_user);
list_add (&pd->list, &__stack_user);
/* Before initializing __stack_user, the debugger could not find us and
had to set __nptl_initial_report_events. Propagate its setting. */
THREAD_SETMEM (pd, report_events, __nptl_initial_report_events);
/* Install the cancellation signal handler. If for some reason we
cannot install the handler we do not abort. Maybe we should, but
it is only asynchronous cancellation which is affected. */
struct sigaction sa;
sa.sa_sigaction = sigcancel_handler;
sa.sa_flags = SA_SIGINFO;
__sigemptyset (&sa.sa_mask);
(void) __libc_sigaction (SIGCANCEL, &sa, NULL);
/* Install the handle to change the threads' uid/gid. */
sa.sa_sigaction = sighandler_setxid;
sa.sa_flags = SA_SIGINFO | SA_RESTART;
(void) __libc_sigaction (SIGSETXID, &sa, NULL);
/* The parent process might have left the signals blocked. Just in
case, unblock it. We reuse the signal mask in the sigaction
structure. It is already cleared. */
__sigaddset (&sa.sa_mask, SIGCANCEL);
__sigaddset (&sa.sa_mask, SIGSETXID);
(void) INTERNAL_SYSCALL (rt_sigprocmask, err, 4, SIG_UNBLOCK, &sa.sa_mask,
NULL, _NSIG / 8);
/* Get the size of the static and alignment requirements for the TLS
block. */
size_t static_tls_align;
_dl_get_tls_static_info (&__static_tls_size, &static_tls_align);
/* Make sure the size takes all the alignments into account. */
if (STACK_ALIGN > static_tls_align)
static_tls_align = STACK_ALIGN;
__static_tls_align_m1 = static_tls_align - 1;
__static_tls_size = roundup (__static_tls_size, static_tls_align);
/* Determine the default allowed stack size. This is the size used
in case the user does not specify one. */
struct rlimit limit;
if (getrlimit (RLIMIT_STACK, &limit) != 0
|| limit.rlim_cur == RLIM_INFINITY)
/* The system limit is not usable. Use an architecture-specific
default. */
limit.rlim_cur = ARCH_STACK_DEFAULT_SIZE;
else if (limit.rlim_cur < PTHREAD_STACK_MIN)
/* The system limit is unusably small.
Use the minimal size acceptable. */
limit.rlim_cur = PTHREAD_STACK_MIN;
/* Make sure it meets the minimum size that allocate_stack
(allocatestack.c) will demand, which depends on the page size. */
const uintptr_t pagesz = GLRO(dl_pagesize);
const size_t minstack = pagesz + __static_tls_size + MINIMAL_REST_STACK;
if (limit.rlim_cur < minstack)
limit.rlim_cur = minstack;
/* Round the resource limit up to page size. */
limit.rlim_cur = (limit.rlim_cur + pagesz - 1) & -pagesz;
lll_lock (__default_pthread_attr_lock, LLL_PRIVATE);
__default_pthread_attr.stacksize = limit.rlim_cur;
__default_pthread_attr.guardsize = GLRO (dl_pagesize);
lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE);
#ifdef SHARED
/* Transfer the old value from the dynamic linker's internal location. */
*__libc_dl_error_tsd () = *(*GL(dl_error_catch_tsd)) ();
GL(dl_error_catch_tsd) = &__libc_dl_error_tsd;
/* 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
GL(dl_init_static_tls) = &__pthread_init_static_tls;
GL(dl_wait_lookup_done) = &__wait_lookup_done;
/* Register the fork generation counter with the libc. */
#ifndef TLS_MULTIPLE_THREADS_IN_TCB
__libc_multiple_threads_ptr =
#endif
__libc_pthread_init (&__fork_generation, __reclaim_stacks,
ptr_pthread_functions);
/* Determine whether the machine is SMP or not. */
__is_smp = is_smp_system ();
}
strong_alias (__pthread_initialize_minimal_internal,
__pthread_initialize_minimal)
size_t
__pthread_get_minstack (const pthread_attr_t *attr)
{
struct pthread_attr *iattr = (struct pthread_attr *) attr;
return (GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN
+ iattr->guardsize);
}