#include <fcntl.h>
#include <errno.h>
#include <unistd.h>
#include <stdint.h>
#include <stdlib.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include "slibtool_mapfile_impl.h"

static void slbt_munmap(void * addr, size_t size)
{
	if (addr) {
		munmap(addr,size);
	}
}

struct slbt_map_info * slbt_map_file(
	int		fdat,
	const char *	path,
	uint32_t	flags)
{
	int 			fd;
	void *			addr;
	struct stat		st;
	uint32_t		oflag;
	uint32_t		mprot;
	struct slbt_map_info *	mapinfo;

	if ((flags & SLBT_MAP_INPUT) && (flags & SLBT_MAP_OUTPUT))  {
		oflag = O_RDWR;
		mprot = PROT_READ|PROT_WRITE;
	} else if (flags & SLBT_MAP_INPUT) {
		oflag = O_RDONLY;
		mprot = PROT_READ;
	} else if (flags & SLBT_MAP_OUTPUT) {
		oflag = O_WRONLY;
		mprot = PROT_WRITE;
	} else {
		errno = EINVAL;
		return 0;
	}

	if ((fd = openat(fdat,path,oflag,0)) < 0)
		return 0;

	if (fstat(fd,&st) < 0) {
		close(fd);
		return 0;
	}

	addr = st.st_size
		? mmap(0,st.st_size,mprot,MAP_SHARED,fd,0)
		: 0;

	if (addr == MAP_FAILED) {
		close(fd);
		return 0;
	}

	if (!(mapinfo = malloc(sizeof(*mapinfo)))) {
		close(fd);
		slbt_munmap(addr,st.st_size);
		return 0;
	}

	close(fd);

	mapinfo->addr = addr;
	mapinfo->size = st.st_size;

	return mapinfo;
}

void slbt_unmap_file(struct slbt_map_info * mapinfo)
{
	slbt_munmap(mapinfo->addr,mapinfo->size);
	free(mapinfo);
}