github.com/afumu/libc@v0.0.6/musl/src/thread/pthread_getattr_np.c (about)

     1  #define _GNU_SOURCE
     2  #include "pthread_impl.h"
     3  #include "libc.h"
     4  #include <sys/mman.h>
     5  
     6  int pthread_getattr_np(pthread_t t, pthread_attr_t *a)
     7  {
     8  	*a = (pthread_attr_t){0};
     9  	a->_a_detach = t->detach_state>=DT_DETACHED;
    10  	a->_a_guardsize = t->guard_size;
    11  	if (t->stack) {
    12  		a->_a_stackaddr = (uintptr_t)t->stack;
    13  		a->_a_stacksize = t->stack_size;
    14  	} else {
    15  		char *p = (void *)libc.auxv;
    16  		size_t l = PAGE_SIZE;
    17  		p += -(uintptr_t)p & PAGE_SIZE-1;
    18  		a->_a_stackaddr = (uintptr_t)p;
    19  		while (mremap(p-l-PAGE_SIZE, PAGE_SIZE, 2*PAGE_SIZE, 0)==MAP_FAILED && errno==ENOMEM)
    20  			l += PAGE_SIZE;
    21  		a->_a_stacksize = l;
    22  	}
    23  	return 0;
    24  }