root/compat/mmap.c

DEFINITIONS

1. git_mmap
2. git_munmap

#include "../git-compat-util.h"

void *git_mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset)
{
        size_t n = 0;

        if (start != NULL || !(flags & MAP_PRIVATE))
                die("Invalid usage of mmap when built with NO_MMAP");

        start = xmalloc(length);
        if (start == NULL) {
                errno = ENOMEM;
                return MAP_FAILED;
        }

        while (n < length) {
                ssize_t count = xpread(fd, (char *)start + n, length - n, offset + n);

                if (count == 0) {
                        memset((char *)start+n, 0, length-n);
                        break;
                }

                if (count < 0) {
                        free(start);
                        errno = EACCES;
                        return MAP_FAILED;
                }

                n += count;
        }

        return start;
}

int git_munmap(void *start, size_t length)
{
        free(start);
        return 0;
}