xref: /openbsd-src/lib/librthread/rthread_attr.c (revision c1e618aa95b061890a098580771ae05e12a10408)

/*	$OpenBSD: rthread_attr.c,v 1.25 2018/05/02 14:06:00 bluhm Exp $ */
/*
 * Copyright (c) 2004,2005 Ted Unangst <tedu@openbsd.org>
 * All Rights Reserved.
 *
 * Permission to use, copy, modify, and distribute this software for any
 * purpose with or without fee is hereby granted, provided that the above
 * copyright notice and this permission notice appear in all copies.
 *
 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
 */
/*
 * generic attribute support
 */

#include <sys/mman.h>

#include <stdint.h>
#include <stdlib.h>
#include <syslog.h>
#include <unistd.h>
#include <errno.h>

#include <pthread.h>
#include <pthread_np.h>

#include "rthread.h"

/*
 * Note: stack_size + guard_size == total stack used
 *
 * pthread_attr_init MUST be called before any other attribute function
 * for proper operation.
 *
 * Every call to pthread_attr_init MUST be matched with a call to
 * pthread_attr_destroy to avoid leaking memory.   This is an implementation
 * requirement, not a POSIX requirement.
 */

int
pthread_attr_init(pthread_attr_t *attrp)
{
	pthread_attr_t attr;

	/* make sure _rthread_attr_default has been initialized */
	if (!_threads_ready)
		_rthread_init();

	attr = calloc(1, sizeof(*attr));
	if (!attr)
		return (errno);
	*attr = _rthread_attr_default;
	*attrp = attr;

	return (0);
}

int
pthread_attr_destroy(pthread_attr_t *attrp)
{
	free(*attrp);
	*attrp = NULL;

	return (0);
}

int
pthread_attr_getguardsize(const pthread_attr_t *attrp, size_t *guardsize)
{
	*guardsize = (*attrp)->guard_size;

	return (0);
}

int
pthread_attr_setguardsize(pthread_attr_t *attrp, size_t guardsize)
{
	(*attrp)->guard_size = guardsize;

	return (0);
}

int
pthread_attr_getdetachstate(const pthread_attr_t *attrp, int *detachstate)
{
	*detachstate = (*attrp)->detach_state;

	return (0);
}

int
pthread_attr_setdetachstate(pthread_attr_t *attrp, int detachstate)
{
	int error;

	error = (detachstate == PTHREAD_CREATE_DETACHED ||
		  detachstate == PTHREAD_CREATE_JOINABLE) ? 0 : EINVAL;
	if (error == 0)
		(*attrp)->detach_state = detachstate;

	return (error);
}

int
pthread_attr_getstack(const pthread_attr_t *attrp, void **stackaddr,
    size_t *stacksize)
{
	*stackaddr = (*attrp)->stack_addr;
	*stacksize = (*attrp)->stack_size;

	return (0);
}

int
pthread_attr_setstack(pthread_attr_t *attrp, void *stackaddr, size_t stacksize)
{
	int error;
	volatile char *p = stackaddr;
	size_t i;
	struct syslog_data data = SYSLOG_DATA_INIT;

	if (stacksize < PTHREAD_STACK_MIN) {
		syslog_r(LOG_ERR, &data,
		    "pthread_attr_setstack(%p, %zu): "
		    "stack size below min size %d",
		    stackaddr, stacksize, PTHREAD_STACK_MIN);
		return (EINVAL);
	}

	/*
	 * Make sure that the stack is page-aligned and a multiple
	 * of the page size
	 */
	if (((uintptr_t)stackaddr % PTHREAD_STACK_MIN) != 0
	    || (stacksize % PTHREAD_STACK_MIN) != 0) {
		syslog_r(LOG_ERR, &data,
		    "pthread_attr_setstack(%p, 0x%zx): "
		    "unaligned thread stack start and/or size",
		    stackaddr, stacksize);
		return (EINVAL);
	}

	/*
	 * We are going to re-mmap() stackaddr to MAP_STACK, but only
	 * if the entire range [stackaddr, stackaddr+stacksize) consists
	 * of valid address that are mapped PROT_READ|PROT_WRITE.
	 * Test this by reading and writing every page.
	 *
	 * XXX: What if the caller has SIGSEGV blocked or ignored?
	 * Then we won't crash here when entering an invalid mapping.
	 */
	for (i = 0; i < stacksize; i += PTHREAD_STACK_MIN) {
		char val = p[i];

		p[i] = val;
	}

	if (mmap(stackaddr, stacksize, PROT_READ|PROT_WRITE,
	    MAP_FIXED|MAP_STACK|MAP_ANON|MAP_PRIVATE, -1, 0) == MAP_FAILED) {
		syslog_r(LOG_ERR, &data,
		    "pthread_attr_setstack(%p, %zu): mmap error %m",
		    stackaddr, stacksize);
		return (errno);
	}

	if ((error = pthread_attr_setstackaddr(attrp, stackaddr)))
		return (error);
	(*attrp)->stack_size = stacksize;

	return (0);
}

int
pthread_attr_getstacksize(const pthread_attr_t *attrp, size_t *stacksize)
{
	*stacksize = (*attrp)->stack_size;

	return (0);
}

int
pthread_attr_setstacksize(pthread_attr_t *attrp, size_t stacksize)
{
	if (!_threads_ready)		/* for ROUND_TO_PAGE */
		_rthread_init();

	if (stacksize < PTHREAD_STACK_MIN ||
	    stacksize > ROUND_TO_PAGE(stacksize))
		return (EINVAL);
	(*attrp)->stack_size = stacksize;

	return (0);
}

int
pthread_attr_getstackaddr(const pthread_attr_t *attrp, void **stackaddr)
{
	*stackaddr = (*attrp)->stack_addr;

	return (0);
}

int
pthread_attr_setstackaddr(pthread_attr_t *attrp, void *stackaddr)
{
	if (!_threads_ready)
		_rthread_init();		/* for _thread_pagesize */

	if (stackaddr == NULL || (uintptr_t)stackaddr & (_thread_pagesize - 1))
		return (EINVAL);
	(*attrp)->stack_addr = stackaddr;

	return (0);
}
DEF_NONSTD(pthread_attr_setstackaddr);

int
pthread_attr_getscope(const pthread_attr_t *attrp, int *contentionscope)
{
	*contentionscope = (*attrp)->contention_scope;

	return (0);
}

int
pthread_attr_setscope(pthread_attr_t *attrp, int contentionscope)
{
	if (contentionscope != PTHREAD_SCOPE_SYSTEM &&
	    contentionscope != PTHREAD_SCOPE_PROCESS)
		return (EINVAL);
	(*attrp)->contention_scope = contentionscope;

	return (0);
}