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mmap.c
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mmap.c
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#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include "../cache.h"
void *gitfakemmap(void *start, size_t length, int prot , int flags, int fd, off_t offset)
{
int n = 0;
if (start != NULL || !(flags & MAP_PRIVATE))
die("Invalid usage of gitfakemmap.");
if (lseek(fd, offset, SEEK_SET) < 0) {
errno = EINVAL;
return MAP_FAILED;
}
start = xmalloc(length);
if (start == NULL) {
errno = ENOMEM;
return MAP_FAILED;
}
while (n < length) {
int count = read(fd, start+n, length-n);
if (count == 0) {
memset(start+n, 0, length-n);
break;
}
if (count < 0) {
free(start);
errno = EACCES;
return MAP_FAILED;
}
n += count;
}
return start;
}
int gitfakemunmap(void *start, size_t length)
{
free(start);
return 0;
}