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/*
* Copyright (c) 2013-2016, Intel Corporation
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
*
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* * Neither the name of Intel Corporation nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef PT_SECTION_H
#define PT_SECTION_H
#include <stdint.h>
#if defined(FEATURE_THREADS)
# include <threads.h>
#endif /* defined(FEATURE_THREADS) */
/* A section of contiguous memory loaded from a file. */
struct pt_section {
/* The name of the file. */
char *filename;
/* The offset into the file. */
uint64_t offset;
/* The (adjusted) size in bytes. The size is truncated to match the
* actual file size.
*/
uint64_t size;
/* A pointer to OS-specific file status for detecting changes.
*
* The status is initialized on first pt_section_map() and will be
* left in the section until the section is destroyed. This field
* is owned by the OS-specific mmap-based section implementation.
*/
void *status;
/* A pointer to implementation-specific mapping information - NULL if
* the section is currently not mapped.
*
* This field is set in pt_section_map() and owned by the mapping
* implementation.
*/
void *mapping;
/* A pointer to the unmap function - NULL if the section is currently
* not mapped.
*
* This field is set in pt_section_map() and owned by the mapping
* implementation.
*/
int (*unmap)(struct pt_section *sec);
/* A pointer to the read function - NULL if the section is currently
* not mapped.
*
* This field is set in pt_section_map() and owned by the mapping
* implementation.
*/
int (*read)(const struct pt_section *sec, uint8_t *buffer,
uint16_t size, uint64_t offset);
#if defined(FEATURE_THREADS)
/* A lock protecting this section.
*
* Most operations do not require the section to be locked. All
* actual locking should be handled by pt_section_* functions.
*/
mtx_t lock;
#endif /* defined(FEATURE_THREADS) */
/* The number of current users. The last user destroys the section. */
uint16_t ucount;
/* The number of current mappers. The last unmaps the section. */
uint16_t mcount;
};
/* Create a section.
*
* The returned section describes the contents of @file starting at @offset
* for @size bytes.
*
* If @file is shorter than the requested @size, the section is silently
* truncated to the size of @file.
*
* If @offset lies beyond the end of @file, no section is created.
*
* The returned section is not mapped and starts with a user count of one.
*
* Returns a new section on success, NULL otherwise.
*/
extern struct pt_section *pt_mk_section(const char *file, uint64_t offset,
uint64_t size);
/* Lock a section.
*
* Locks @section. The section must not be locked.
*
* Returns a new section on success, NULL otherwise.
* Returns -pte_bad_lock on any locking error.
*/
extern int pt_section_lock(struct pt_section *section);
/* Unlock a section.
*
* Unlocks @section. The section must be locked.
*
* Returns a new section on success, NULL otherwise.
* Returns -pte_bad_lock on any locking error.
*/
extern int pt_section_unlock(struct pt_section *section);
/* Add another user.
*
* Increments the user count of @section.
*
* Returns zero on success, a negative error code otherwise.
* Returns -pte_internal if @section is NULL.
* Returns -pte_internal if the user count would overflow.
* Returns -pte_bad_lock on any locking error.
*/
extern int pt_section_get(struct pt_section *section);
/* Remove a user.
*
* Decrements the user count of @section. Destroys the section if the
* count reaches zero.
*
* Returns zero on success, a negative error code otherwise.
* Returns -pte_internal if @section is NULL.
* Returns -pte_internal if the user count is already zero.
* Returns -pte_bad_lock on any locking error.
*/
extern int pt_section_put(struct pt_section *section);
/* Return the filename of @section. */
extern const char *pt_section_filename(const struct pt_section *section);
/* Return the size of the section in bytes. */
extern uint64_t pt_section_size(const struct pt_section *section);
/* Create the OS-specific file status.
*
* On success, allocates a status object, provides a pointer to it in @pstatus
* and provides the file size in @psize.
*
* The status object will be free()'ed when its section is.
*
* This function is implemented in the OS-specific section implementation.
*
* Returns zero on success, a negative error code otherwise.
* Returns -pte_internal if @pstatus, @psize, or @filename is NULL.
* Returns -pte_bad_image if @filename can't be opened.
* Returns -pte_nomem if the status object can't be allocated.
*/
extern int pt_section_mk_status(void **pstatus, uint64_t *psize,
const char *filename);
/* Map a section.
*
* Maps @section into memory. Mappings are use-counted. The number of
* pt_section_map() calls must match the number of pt_section_unmap()
* calls.
*
* This function is implemented in the OS-specific section implementation.
*
* Returns zero on success, a negative error code otherwise.
* Returns -pte_internal if @section is NULL.
* Returns -pte_bad_image if @section changed or can't be opened.
* Returns -pte_bad_lock on any locking error.
* Returns -pte_nomem if @section can't be mapped into memory.
*/
extern int pt_section_map(struct pt_section *section);
/* Unmap a section.
*
* Unmaps @section from memory.
*
* Returns zero on success, a negative error code otherwise.
* Returns -pte_internal if @section is NULL.
* Returns -pte_bad_lock on any locking error.
* Returns -pte_internal if @section has not been mapped.
*/
extern int pt_section_unmap(struct pt_section *section);
/* Read memory from a section.
*
* Reads at most @size bytes from @section at @offset into @buffer. @section
* must be mapped.
*
* Returns the number of bytes read on success, a negative error code otherwise.
* Returns -pte_invalid if @section or @buffer are NULL.
* Returns -pte_nomap if @offset is beyond the end of the section.
*/
extern int pt_section_read(const struct pt_section *section, uint8_t *buffer,
uint16_t size, uint64_t offset);
#endif /* PT_SECTION_H */
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