static struct zip_cdir *
_zip_find_central_dir(FILE *fp, unsigned int flags, int *zep, off_t len)
{
struct zip_cdir *cdir, *cdirnew;
unsigned char *buf, *match;
off_t buf_offset;
size_t buflen;
zip_int64_t a, i;
zip_int64_t best;
struct zip_error zerr;
if (len < (off_t)EOCDLEN) {
set_error(zep, NULL, ZIP_ER_NOZIP);
return NULL;
}
i = fseeko(fp, -(len < CDBUFSIZE ? len : CDBUFSIZE), SEEK_END);
if (i == -1 && errno != EFBIG) {
/* seek before start of file on my machine */
set_error(zep, NULL, ZIP_ER_SEEK);
return NULL;
}
buf_offset = ftello(fp);
/* 64k is too much for stack */
if ((buf=(unsigned char *)malloc(CDBUFSIZE)) == NULL) {
set_error(zep, NULL, ZIP_ER_MEMORY);
return NULL;
}
clearerr(fp);
buflen = fread(buf, 1, CDBUFSIZE, fp);
if (ferror(fp)) {
set_error(zep, NULL, ZIP_ER_READ);
free(buf);
return NULL;
}
best = -1;
cdir = NULL;
match = buf+ (buflen < CDBUFSIZE ? 0 : EOCD64LOCLEN);
_zip_error_set(&zerr, ZIP_ER_NOZIP, 0);
while ((match=_zip_memmem(match, buflen-(size_t)(match-buf)-(EOCDLEN-4),
(const unsigned char *)EOCD_MAGIC, 4))!=NULL) {
/* found match -- check, if good */
/* to avoid finding the same match all over again */
match++;
if ((cdirnew=_zip_readcdir(fp, buf_offset, buf, match-1, buflen, flags,
&zerr)) == NULL)
continue;
if (cdir) {
if (best <= 0)
best = _zip_checkcons(fp, cdir, &zerr);
a = _zip_checkcons(fp, cdirnew, &zerr);
if (best < a) {
_zip_cdir_free(cdir);
cdir = cdirnew;
best = a;
}
else
_zip_cdir_free(cdirnew);
}
else {
cdir = cdirnew;
if (flags & ZIP_CHECKCONS)
best = _zip_checkcons(fp, cdir, &zerr);
else
best = 0;
}
cdirnew = NULL;
}
free(buf);
if (best < 0) {
set_error(zep, &zerr, 0);
_zip_cdir_free(cdir);
return NULL;
}
return cdir;
}
static zip_cdir_t *
_zip_find_central_dir(zip_t *za, zip_uint64_t len)
{
zip_cdir_t *cdir, *cdirnew;
zip_uint8_t *match;
zip_int64_t buf_offset;
zip_uint64_t buflen;
zip_int64_t a;
zip_int64_t best;
zip_error_t error;
zip_buffer_t *buffer;
if (len < EOCDLEN) {
zip_error_set(&za->error, ZIP_ER_NOZIP, 0);
return NULL;
}
buflen = (len < CDBUFSIZE ? len : CDBUFSIZE);
if (zip_source_seek(za->src, -(zip_int64_t)buflen, SEEK_END) < 0) {
zip_error_t *src_error = zip_source_error(za->src);
if (zip_error_code_zip(src_error) != ZIP_ER_SEEK || zip_error_code_system(src_error) != EFBIG) {
/* seek before start of file on my machine */
_zip_error_copy(&za->error, src_error);
return NULL;
}
}
if ((buf_offset = zip_source_tell(za->src)) < 0) {
_zip_error_set_from_source(&za->error, za->src);
return NULL;
}
if ((buffer = _zip_buffer_new_from_source(za->src, buflen, NULL, &za->error)) == NULL) {
return NULL;
}
best = -1;
cdir = NULL;
if (buflen >= CDBUFSIZE) {
/* EOCD64 locator is before EOCD, so leave place for it */
_zip_buffer_set_offset(buffer, EOCD64LOCLEN);
}
zip_error_set(&error, ZIP_ER_NOZIP, 0);
match = _zip_buffer_get(buffer, 0);
while ((match=_zip_memmem(match, _zip_buffer_left(buffer)-(EOCDLEN-4), (const unsigned char *)EOCD_MAGIC, 4)) != NULL) {
_zip_buffer_set_offset(buffer, (zip_uint64_t)(match - _zip_buffer_data(buffer)));
if ((cdirnew = _zip_read_cdir(za, buffer, (zip_uint64_t)buf_offset, &error)) != NULL) {
if (cdir) {
if (best <= 0) {
best = _zip_checkcons(za, cdir, &error);
}
a = _zip_checkcons(za, cdirnew, &error);
if (best < a) {
_zip_cdir_free(cdir);
cdir = cdirnew;
best = a;
}
else {
_zip_cdir_free(cdirnew);
}
}
else {
cdir = cdirnew;
if (za->open_flags & ZIP_CHECKCONS)
best = _zip_checkcons(za, cdir, &error);
else {
best = 0;
}
}
cdirnew = NULL;
}
match++;
_zip_buffer_set_offset(buffer, (zip_uint64_t)(match - _zip_buffer_data(buffer)));
}
_zip_buffer_free(buffer);
if (best < 0) {
_zip_error_copy(&za->error, &error);
_zip_cdir_free(cdir);
return NULL;
}
return cdir;
}
