Added some license and readme.

[minimal.git] / mapping.h

/* Minimal - the simplest thing that could possibly work
 * Copyright (C) 2007  Jay Freeman (saurik)
*/

/*
 *        Redistribution and use in source and binary
 * forms, with or without modification, are permitted
 * provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the
 *    above copyright notice, this list of conditions
 *    and the following disclaimer.
 * 2. 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.
 * 3. The name of the author may not be used to endorse
 *    or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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.
*/

#include <sys/mman.h>

#include <errno.h>
#include <unistd.h>

#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>

void *map(const char *path, size_t offset, size_t size, size_t *psize, bool ro) {
    int fd;
    _syscall(fd = open(path, ro ? O_RDONLY : O_RDWR));

    if (size == _not(size_t)) {
        struct stat stat;
        _syscall(fstat(fd, &stat));
        size = stat.st_size;
    }

    if (psize != NULL)
        *psize = size;

    void *base;
    _syscall(base = mmap(NULL, size, ro ? PROT_READ : PROT_READ | PROT_WRITE, MAP_SHARED, fd, offset));

    _syscall(close(fd));
    return base;
}