static struct cdir_entry *
find_cdir_entry (struct cdir_entry *entry, int count, const char *name)
{
size_t name_size = strlen(name);
while (count--) {
if (letoh16(entry->filename_size) == name_size &&
!memcmp(entry->data, name, name_size))
return entry;
entry = (struct cdir_entry *)((char *)entry + cdir_entry_size(entry));
}
return NULL;
}
static uint32_t find_lowest_offset(struct cdir_entry *entry, int count)
{
uint32_t lowest_offset = zip_size;
while (count--) {
uint32_t entry_offset = le32toh(entry->offset);
if (lowest_offset > entry_offset)
lowest_offset = entry_offset;
if (le32toh(entry->signature) != 0x02014b50) {
printf("invalid signature on cdir_entry! (count=%d)\n", count);
exit(-1);
}
entry = (struct cdir_entry *)((char *)entry + cdir_entry_size(entry));
}
return lowest_offset;
}
static int
repack(bool flatten, const char *dstpath, const char *srcpath)
{
char *src_zip = (char *)map_file(srcpath);
if (!src_zip) {
printf("Could not open zip file.\n");
return -1;
}
int fd = creat(dstpath, 0777);
if (fd == -1) {
printf("can't open output file\n");
return -1;
}
struct cdir_end *dirend = (struct cdir_end *)(src_zip + zip_size - sizeof(*dirend));
while ((void *)dirend > src_zip &&
le32toh(dirend->signature) != 0x06054b50)
dirend = (struct cdir_end *)((char *)dirend - 1);
if (le32toh(dirend->signature) != 0x06054b50) {
printf("couldn't find end of central directory record!\n");
return -1;
}
uint32_t cdir_offset = le32toh(dirend->cdir_offset);
uint16_t cdir_entries = le16toh(dirend->cdir_entries);
uint32_t cdir_size = le32toh(dirend->cdir_size);
TRACE("Found %d entries. cdir offset at %d\n",
cdir_entries, cdir_offset);
struct cdir_entry *cdir_start = (struct cdir_entry *)(src_zip + cdir_offset);
struct cdir_entry *new_cdir_start = (struct cdir_entry *)malloc(cdir_size);
if (!new_cdir_start) {
TRACE("couldn't allocate central directory copy\n");
return -1;
}
memcpy(new_cdir_start, cdir_start, cdir_size);
uint32_t lowest_offset = find_lowest_offset(cdir_start, cdir_entries);
uint32_t out_offset = simple_write(fd, src_zip, lowest_offset);
struct cdir_entry *current_entry = new_cdir_start;
uint16_t i = cdir_entries;
while (i--) {
struct local_file_header *file = (struct local_file_header *)(src_zip + le32toh(current_entry->offset));
int rc;
if (flatten)
rc = flatten_entry(fd, file, current_entry, out_offset);
else
rc = squeeze_entry(fd, file, current_entry, out_offset);
if (rc)
return rc;
current_entry = (struct cdir_entry *)((char *)current_entry + cdir_entry_size(current_entry));
}
uint32_t new_cdir_offset;
if (cdir_offset < lowest_offset) {
TRACE("Doing in place cdir replacement at %d\n", cdir_offset);
new_cdir_offset = cdir_offset;
lseek(fd, SEEK_SET, cdir_offset);
simple_write(fd, (char *)new_cdir_start, cdir_size);
lseek(fd, SEEK_END, 0);
} else {
new_cdir_offset = out_offset;
TRACE("Appending cdir at %d\n", new_cdir_offset);
simple_write(fd, (char *)new_cdir_start, cdir_size);
}
struct cdir_end end;
memcpy(&end, dirend, sizeof(end));
end.cdir_offset = htole32(new_cdir_offset);
simple_write(fd, (char *)&end, sizeof(end));
close(fd);
munmap(src_zip, zip_size);
return 0;
}