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implement pthread_getattr_np

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this function is mainly (purely?) for obtaining stack address
information, but we also provide the detach state since it's easy to
do anyway.
This commit is contained in:
Rich Felker 2013-03-31 23:25:55 -04:00
commit 14a835b386
3 changed files with 31 additions and 2 deletions
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2
src/internal/pthread_impl.h
View file

@ -23,6 +23,8 @@ struct pthread {
int detached; int detached;
unsigned char *map_base; unsigned char *map_base;
size_t map_size; size_t map_size;
void *stack;
size_t stack_size;
void *start_arg; void *start_arg;
void *(*start)(void *); void *(*start)(void *);
void *result; void *result;

10
src/thread/pthread_create.c
View file

@ -101,7 +101,7 @@ int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp
int ret; int ret;
size_t size, guard; size_t size, guard;
struct pthread *self = pthread_self(), *new; struct pthread *self = pthread_self(), *new;
unsigned char *map = 0, *stack = 0, *tsd = 0; unsigned char *map = 0, *stack = 0, *tsd = 0, *stack_limit;
unsigned flags = 0x7d8f00; unsigned flags = 0x7d8f00;
int do_sched = 0; int do_sched = 0;
pthread_attr_t attr = {0}; pthread_attr_t attr = {0};
@ -123,6 +123,7 @@ int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp
size_t need = libc.tls_size + __pthread_tsd_size; size_t need = libc.tls_size + __pthread_tsd_size;
size = attr._a_stacksize + DEFAULT_STACK_SIZE; size = attr._a_stacksize + DEFAULT_STACK_SIZE;
stack = (void *)(attr._a_stackaddr & -16); stack = (void *)(attr._a_stackaddr & -16);
stack_limit = attr._a_stackaddr - size;
/* Use application-provided stack for TLS only when /* Use application-provided stack for TLS only when
* it does not take more than ~12% or 2k of the * it does not take more than ~12% or 2k of the
* application's stack space. */ * application's stack space. */
@ -152,12 +153,17 @@ int pthread_create(pthread_t *restrict res, const pthread_attr_t *restrict attrp
if (map == MAP_FAILED) goto fail; if (map == MAP_FAILED) goto fail;
} }
tsd = map + size - __pthread_tsd_size; tsd = map + size - __pthread_tsd_size;
if (!stack) stack = tsd - libc.tls_size; if (!stack) {
stack = tsd - libc.tls_size;
stack_limit = map + guard;
}
} }
new = __copy_tls(tsd - libc.tls_size); new = __copy_tls(tsd - libc.tls_size);
new->map_base = map; new->map_base = map;
new->map_size = size; new->map_size = size;
new->stack = stack;
new->stack_size = stack - stack_limit;
new->pid = self->pid; new->pid = self->pid;
new->errno_ptr = &new->errno_val; new->errno_ptr = &new->errno_val;
new->start = entry; new->start = entry;

21
src/thread/pthread_getattr_np.c Normal file
View file

@ -0,0 +1,21 @@
#include "pthread_impl.h"
#include <sys/mman.h>
int pthread_getattr_np(pthread_t t, pthread_attr_t *a)
{
*a = (pthread_attr_t){0};
a->_a_detach = !!t->detached;
if (t->stack) {
a->_a_stackaddr = (uintptr_t)t->stack;
a->_a_stacksize = t->stack_size - DEFAULT_STACK_SIZE;
} else {
char *p = (void *)libc.auxv;
size_t l = PAGE_SIZE;
p += -(uintptr_t)p & PAGE_SIZE-1;
a->_a_stackaddr = (uintptr_t)p;
while (!posix_madvise(p-l-PAGE_SIZE, PAGE_SIZE, POSIX_MADV_NORMAL))
l += PAGE_SIZE;
a->_a_stacksize = l - DEFAULT_STACK_SIZE;
}
return 0;
}