[babeltrace.git] / include / babeltrace / mmap-align-internal.h

#ifndef _BABELTRACE_MMAP_ALIGN_H
#define _BABELTRACE_MMAP_ALIGN_H

/*
 * Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#include <babeltrace/align-internal.h>
#include <stdlib.h>
#include <stdint.h>
#include <babeltrace/compat/mman-internal.h>
#include <babeltrace/common-internal.h>

/*
 * This header implements a wrapper over mmap (mmap_align) that memory
 * maps a file region that is not necessarily multiple of the page size.
 * It returns a structure (instead of a pointer) that contains the mmap
 * pointer (page-aligned) and a pointer to the offset requested within
 * that page. Note: in the current implementation, the "addr" parameter
 * cannot be forced, so we allocate at an address chosen by the OS.
 */

struct mmap_align {
	void *page_aligned_addr;	/* mmap address, aligned to floor */
	size_t page_aligned_length;	/* mmap length, containing range */

	void *addr;			/* virtual mmap address */
	size_t length;			/* virtual mmap length */
};

#ifdef __WIN32__
#include <windows.h>

/*
 * On windows the memory mapping offset must be aligned to the memory
 * allocator allocation granularity and not the page size.
 */
static inline
off_t get_page_aligned_offset(off_t offset, size_t page_size)
{
       SYSTEM_INFO sysinfo;

       GetNativeSystemInfo(&sysinfo);

       return ALIGN_FLOOR(offset, sysinfo.dwAllocationGranularity);
}
#else
static inline
off_t get_page_aligned_offset(off_t offset, size_t page_size)
{
       return ALIGN_FLOOR(offset, page_size);
}
#endif

static inline
struct mmap_align *mmap_align(size_t length, int prot,
		int flags, int fd, off_t offset)
{
	struct mmap_align *mma;
	off_t page_aligned_offset;	/* mmap offset, aligned to floor */
	size_t page_size;

	page_size = bt_common_get_page_size();

	mma = malloc(sizeof(*mma));
	if (!mma)
		return MAP_FAILED;
	mma->length = length;
	page_aligned_offset = get_page_aligned_offset(offset, page_size);
	/*
	 * Page aligned length needs to contain the requested range.
	 * E.g., for a small range that fits within a single page, we might
	 * require a 2 pages page_aligned_length if the range crosses a page
	 * boundary.
	 */
	mma->page_aligned_length = ALIGN(length + offset - page_aligned_offset, page_size);
	mma->page_aligned_addr = bt_mmap(NULL, mma->page_aligned_length,
		prot, flags, fd, page_aligned_offset);
	if (mma->page_aligned_addr == MAP_FAILED) {
		free(mma);
		return MAP_FAILED;
	}
	mma->addr = ((uint8_t *) mma->page_aligned_addr) + (offset - page_aligned_offset);
	return mma;
}

static inline
int munmap_align(struct mmap_align *mma)
{
	void *page_aligned_addr;
	size_t page_aligned_length;

	page_aligned_addr = mma->page_aligned_addr;
	page_aligned_length = mma->page_aligned_length;
	free(mma);
	return bt_munmap(page_aligned_addr, page_aligned_length);
}

static inline
void *mmap_align_addr(struct mmap_align *mma)
{
	return mma->addr;
}

/*
 * Helper for special-cases, normally unused.
 */
static inline
void mmap_align_set_addr(struct mmap_align *mma, void *addr)
{
	mma->addr = addr;
}

#endif /* _BABELTRACE_MMAP_ALIGN_H */
Commit	Line	Data
	1	#ifndef _BABELTRACE_MMAP_ALIGN_H
	2	#define _BABELTRACE_MMAP_ALIGN_H
	3
	4	/*
	5	* Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	6	*
	7	* Permission is hereby granted, free of charge, to any person obtaining a copy
	8	* of this software and associated documentation files (the "Software"), to deal
	9	* in the Software without restriction, including without limitation the rights
	10	* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
	11	* copies of the Software, and to permit persons to whom the Software is
	12	* furnished to do so, subject to the following conditions:
	13	*
	14	* The above copyright notice and this permission notice shall be included in
	15	* all copies or substantial portions of the Software.
	16	*
	17	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	18	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	19	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	20	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	21	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
	22	* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
	23	* SOFTWARE.
	24	*/
	25
	26	#include <babeltrace/align-internal.h>
	27	#include <stdlib.h>
	28	#include <stdint.h>
	29	#include <babeltrace/compat/mman-internal.h>
	30	#include <babeltrace/common-internal.h>
	31
	32	/*
	33	* This header implements a wrapper over mmap (mmap_align) that memory
	34	* maps a file region that is not necessarily multiple of the page size.
	35	* It returns a structure (instead of a pointer) that contains the mmap
	36	* pointer (page-aligned) and a pointer to the offset requested within
	37	* that page. Note: in the current implementation, the "addr" parameter
	38	* cannot be forced, so we allocate at an address chosen by the OS.
	39	*/
	40
	41	struct mmap_align {
	42	void page_aligned_addr; / mmap address, aligned to floor */
	43	size_t page_aligned_length; /* mmap length, containing range */
	44
	45	void addr; / virtual mmap address */
	46	size_t length; /* virtual mmap length */
	47	};
	48
	49	#ifdef __WIN32__
	50	#include <windows.h>
	51
	52	/*
	53	* On windows the memory mapping offset must be aligned to the memory
	54	* allocator allocation granularity and not the page size.
	55	*/
	56	static inline
	57	off_t get_page_aligned_offset(off_t offset, size_t page_size)
	58	{
	59	SYSTEM_INFO sysinfo;
	60
	61	GetNativeSystemInfo(&sysinfo);
	62
	63	return ALIGN_FLOOR(offset, sysinfo.dwAllocationGranularity);
	64	}
	65	#else
	66	static inline
	67	off_t get_page_aligned_offset(off_t offset, size_t page_size)
	68	{
	69	return ALIGN_FLOOR(offset, page_size);
	70	}
	71	#endif
	72
	73	static inline
	74	struct mmap_align *mmap_align(size_t length, int prot,
	75	int flags, int fd, off_t offset)
	76	{
	77	struct mmap_align *mma;
	78	off_t page_aligned_offset; /* mmap offset, aligned to floor */
	79	size_t page_size;
	80
	81	page_size = bt_common_get_page_size();
	82
	83	mma = malloc(sizeof(*mma));
	84	if (!mma)
	85	return MAP_FAILED;
	86	mma->length = length;
	87	page_aligned_offset = get_page_aligned_offset(offset, page_size);
	88	/*
	89	* Page aligned length needs to contain the requested range.
	90	* E.g., for a small range that fits within a single page, we might
	91	* require a 2 pages page_aligned_length if the range crosses a page
	92	* boundary.
	93	*/
	94	mma->page_aligned_length = ALIGN(length + offset - page_aligned_offset, page_size);
	95	mma->page_aligned_addr = bt_mmap(NULL, mma->page_aligned_length,
	96	prot, flags, fd, page_aligned_offset);
	97	if (mma->page_aligned_addr == MAP_FAILED) {
	98	free(mma);
	99	return MAP_FAILED;
	100	}
	101	mma->addr = ((uint8_t *) mma->page_aligned_addr) + (offset - page_aligned_offset);
	102	return mma;
	103	}
	104
	105	static inline
	106	int munmap_align(struct mmap_align *mma)
	107	{
	108	void *page_aligned_addr;
	109	size_t page_aligned_length;
	110
	111	page_aligned_addr = mma->page_aligned_addr;
	112	page_aligned_length = mma->page_aligned_length;
	113	free(mma);
	114	return bt_munmap(page_aligned_addr, page_aligned_length);
	115	}
	116
	117	static inline
	118	void mmap_align_addr(struct mmap_align mma)
	119	{
	120	return mma->addr;
	121	}
	122
	123	/*
	124	* Helper for special-cases, normally unused.
	125	*/
	126	static inline
	127	void mmap_align_set_addr(struct mmap_align mma, void addr)
	128	{
	129	mma->addr = addr;
	130	}
	131
	132	#endif /* _BABELTRACE_MMAP_ALIGN_H */