glibc/nptl/nptl-init.c
Florian Weimer 2f69522d46 nptl: Perform signal initialization upon pthread_create
Install signal handlers and unblock signals before pthread_create
creates the first thread.

create_thread in sysdeps/unix/sysv/linux/createthread.c can send
SIGCANCEL to the current thread, so the SIGCANCEL handler is currently
needed even if pthread_cancel is never called.  (The way timer_create
uses SIGCANCEL does not need a signal handler; both SIG_DFL and SIG_IGN
dispositions should work.)

Reviewed-by: Adhemerval Zanella  <adhemerval.zanella@linaro.org>
2021-05-21 22:35:00 +02:00

106 lines
3.9 KiB
C

/* Copyright (C) 2002-2021 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
<https://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 <version.h>
#include <shlib-compat.h>
#include <lowlevellock.h>
#include <futex-internal.h>
#include <kernel-features.h>
#include <libc-pointer-arith.h>
#include <pthread_mutex_conf.h>
/* Size and alignment of static TLS block. */
size_t __static_tls_size;
size_t __static_tls_align_m1;
/* Version of the library, used in libthread_db to detect mismatches. */
static const char nptl_version[] __attribute_used__ = VERSION;
void
__pthread_initialize_minimal_internal (void)
{
/* 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 = ALIGN_UP (limit.rlim_cur, pagesz);
lll_lock (__default_pthread_attr_lock, LLL_PRIVATE);
__default_pthread_attr.internal.stacksize = limit.rlim_cur;
__default_pthread_attr.internal.guardsize = GLRO (dl_pagesize);
lll_unlock (__default_pthread_attr_lock, LLL_PRIVATE);
}
strong_alias (__pthread_initialize_minimal_internal,
__pthread_initialize_minimal)
/* This function is internal (it has a GLIBC_PRIVATE) version, but it
is widely used (either via weak symbol, or dlsym) to obtain the
__static_tls_size value. This value is then used to adjust the
value of the stack size attribute, so that applications receive the
full requested stack size, not diminished by the TCB and static TLS
allocation on the stack. Once the TCB is separately allocated,
this function should be removed or renamed (if it is still
necessary at that point). */
size_t
__pthread_get_minstack (const pthread_attr_t *attr)
{
return GLRO(dl_pagesize) + __static_tls_size + PTHREAD_STACK_MIN;
}