/*
* Searches for end of central directory (END) header. The contents of
* the END header will be read and placed in endbuf. Returns the file
* position of the END header, otherwise returns -1 if the END header
* was not found or an error occurred.
*/
static jlong
findEND(jzfile *zip, void *endbuf)
{
char buf[READBLOCKSZ];
jlong pos;
const jlong len = zip->len;
const ZFILE zfd = zip->zfd;
const jlong minHDR = len - END_MAXLEN > 0 ? len - END_MAXLEN : 0;
const jlong minPos = minHDR - (sizeof(buf)-ENDHDR);
jint clen;
for (pos = len - sizeof(buf); pos >= minPos; pos -= (sizeof(buf)-ENDHDR)) {
int i;
jlong off = 0;
if (pos < 0) {
/* Pretend there are some NUL bytes before start of file */
off = -pos;
memset(buf, '\0', (size_t)off);
}
if (readFullyAt(zfd, buf + off, sizeof(buf) - off,
pos + off) == -1) {
return -1; /* System error */
}
/* Now scan the block backwards for END header signature */
for (i = sizeof(buf) - ENDHDR; i >= 0; i--) {
if (buf[i+0] == 'P' &&
buf[i+1] == 'K' &&
buf[i+2] == '\005' &&
buf[i+3] == '\006' &&
((pos + i + ENDHDR + ENDCOM(buf + i) == len)
|| verifyEND(zip, pos + i, buf + i))) {
/* Found END header */
memcpy(endbuf, buf + i, ENDHDR);
clen = ENDCOM(endbuf);
if (clen != 0) {
zip->comment = malloc(clen + 1);
if (zip->comment == NULL) {
return -1;
}
if (readFullyAt(zfd, zip->comment, clen, pos + i + ENDHDR)
== -1) {
free(zip->comment);
zip->comment = NULL;
return -1;
}
zip->comment[clen] = '\0';
zip->clen = clen;
}
return pos + i;
}
}
}
return -1; /* END header not found */
}
/*
* Searches for the ZIP64 end of central directory (END) header. The
* contents of the ZIP64 END header will be read and placed in end64buf.
* Returns the file position of the ZIP64 END header, otherwise returns
* -1 if the END header was not found or an error occurred.
*
* The ZIP format specifies the "position" of each related record as
* ...
* [central directory]
* [zip64 end of central directory record]
* [zip64 end of central directory locator]
* [end of central directory record]
*
* The offset of zip64 end locator can be calculated from endpos as
* "endpos - ZIP64_LOCHDR".
* The "offset" of zip64 end record is stored in zip64 end locator.
*/
static jlong
findEND64(jzfile *zip, void *end64buf, jlong endpos)
{
char loc64[ZIP64_LOCHDR];
jlong end64pos;
if (readFullyAt(zip->zfd, loc64, ZIP64_LOCHDR, endpos - ZIP64_LOCHDR) == -1) {
return -1; // end64 locator not found
}
end64pos = ZIP64_LOCOFF(loc64);
if (readFullyAt(zip->zfd, end64buf, ZIP64_ENDHDR, end64pos) == -1) {
return -1; // end64 record not found
}
return end64pos;
}
static jboolean verifyEND(jzfile *zip, jlong endpos, char *endbuf) {
/* ENDSIG matched, however the size of file comment in it does not
match the real size. One "common" cause for this problem is some
"extra" bytes are padded at the end of the zipfile.
Let's do some extra verification, we don't care about the performance
in this situation.
*/
jlong cenpos = endpos - ENDSIZ(endbuf);
jlong locpos = cenpos - ENDOFF(endbuf);
char buf[4];
return (cenpos >= 0 &&
locpos >= 0 &&
readFullyAt(zip->zfd, buf, sizeof(buf), cenpos) != -1 &&
GETSIG(buf) == CENSIG &&
readFullyAt(zip->zfd, buf, sizeof(buf), locpos) != -1 &&
GETSIG(buf) == LOCSIG);
}
static char *
readCENHeader(jzfile *zip, jlong cenpos, jint bufsize)
{
jint censize;
ZFILE zfd = zip->zfd;
char *cen;
if (bufsize > zip->len - cenpos)
bufsize = (jint)(zip->len - cenpos);
if ((cen = malloc(bufsize)) == NULL) goto Catch;
if (readFullyAt(zfd, cen, bufsize, cenpos) == -1) goto Catch;
censize = CENSIZE(cen);
if (censize <= bufsize) return cen;
if ((cen = realloc(cen, censize)) == NULL) goto Catch;
if (readFully(zfd, cen+bufsize, censize-bufsize) == -1) goto Catch;
return cen;
Catch:
free(cen);
return NULL;
}
static long
fixEND(FILE *zfd, long len)
{
char buf[READBLOCKSZ];
long pos;
const long minHDR = len - END_MAXLEN > 0 ? len - END_MAXLEN : 0;
const long minPos = minHDR - (sizeof(buf)-ENDHDR);
for (pos = len - sizeof(buf); pos >= minPos; pos -= (sizeof(buf)-ENDHDR)) {
int i;
long off = 0;
if (pos < 0) {
/* Pretend there are some NUL bytes before start of file */
off = -pos;
memset(buf, '\0', off);
}
if (readFullyAt(zfd, buf + off, sizeof(buf) - off,
pos + off) == -1) {
return -1; /* System error */
}
/* Now scan the block backwards for END header signature */
for (i = sizeof(buf) - ENDHDR; i >= 0; i--) {
if (buf[i+0] == 'P' &&
buf[i+1] == 'K' &&
buf[i+2] == '\005' &&
buf[i+3] == '\006') {
unsigned int virSize = pos + i + ENDHDR + ENDCOM(buf + i);
if (virSize != len) {
setFileLength(zfd, virSize);
}
return pos + i;
}
}
}
return 0; /* END header not found */
}
/*
* Reads zip file central directory. Returns the file position of first
* CEN header, otherwise returns -1 if an error occured. If zip->msg != NULL
* then the error was a zip format error and zip->msg has the error text.
* Always pass in -1 for knownTotal; it's used for a recursive call.
*/
static jlong
readCEN(jzfile *zip, jint knownTotal)
{
/* Following are unsigned 32-bit */
jlong endpos, end64pos, cenpos, cenlen, cenoff;
/* Following are unsigned 16-bit */
jint total, tablelen, i, j;
unsigned char *cenbuf = NULL;
unsigned char *cenend;
unsigned char *cp;
#ifdef USE_MMAP
static jlong pagesize;
jlong offset;
#endif
unsigned char endbuf[ENDHDR];
jint endhdrlen = ENDHDR;
jzcell *entries;
jint *table;
/* Clear previous zip error */
zip->msg = NULL;
/* Get position of END header */
if ((endpos = findEND(zip, endbuf)) == -1)
return -1; /* no END header or system error */
if (endpos == 0) return 0; /* only END header present */
freeCEN(zip);
/* Get position and length of central directory */
cenlen = ENDSIZ(endbuf);
cenoff = ENDOFF(endbuf);
total = ENDTOT(endbuf);
if (cenlen == ZIP64_MAGICVAL || cenoff == ZIP64_MAGICVAL ||
total == ZIP64_MAGICCOUNT) {
unsigned char end64buf[ZIP64_ENDHDR];
if ((end64pos = findEND64(zip, end64buf, endpos)) != -1) {
cenlen = ZIP64_ENDSIZ(end64buf);
cenoff = ZIP64_ENDOFF(end64buf);
total = (jint)ZIP64_ENDTOT(end64buf);
endpos = end64pos;
endhdrlen = ZIP64_ENDHDR;
}
}
if (cenlen > endpos)
ZIP_FORMAT_ERROR("invalid END header (bad central directory size)");
cenpos = endpos - cenlen;
/* Get position of first local file (LOC) header, taking into
* account that there may be a stub prefixed to the zip file. */
zip->locpos = cenpos - cenoff;
if (zip->locpos < 0)
ZIP_FORMAT_ERROR("invalid END header (bad central directory offset)");
#ifdef USE_MMAP
if (zip->usemmap) {
/* On Solaris & Linux prior to JDK 6, we used to mmap the whole jar file to
* read the jar file contents. However, this greatly increased the perceived
* footprint numbers because the mmap'ed pages were adding into the totals shown
* by 'ps' and 'top'. We switched to mmaping only the central directory of jar
* file while calling 'read' to read the rest of jar file. Here are a list of
* reasons apart from above of why we are doing so:
* 1. Greatly reduces mmap overhead after startup complete;
* 2. Avoids dual path code maintainance;
* 3. Greatly reduces risk of address space (not virtual memory) exhaustion.
*/
if (pagesize == 0) {
pagesize = (jlong)sysconf(_SC_PAGESIZE);
if (pagesize == 0) goto Catch;
}
if (cenpos > pagesize) {
offset = cenpos & ~(pagesize - 1);
} else {
offset = 0;
}
/* When we are not calling recursively, knownTotal is -1. */
if (knownTotal == -1) {
void* mappedAddr;
/* Mmap the CEN and END part only. We have to figure
out the page size in order to make offset to be multiples of
page size.
*/
zip->mlen = cenpos - offset + cenlen + endhdrlen;
zip->offset = offset;
mappedAddr = mmap64(0, zip->mlen, PROT_READ, MAP_SHARED, zip->zfd, (off64_t) offset);
zip->maddr = (mappedAddr == (void*) MAP_FAILED) ? NULL :
(unsigned char*)mappedAddr;
if (zip->maddr == NULL) {
jio_fprintf(stderr, "mmap failed for CEN and END part of zip file\n");
goto Catch;
}
}
cenbuf = zip->maddr + cenpos - offset;
} else
#endif
{
if ((cenbuf = malloc((size_t) cenlen)) == NULL ||
(readFullyAt(zip->zfd, cenbuf, cenlen, cenpos) == -1))
goto Catch;
}
cenend = cenbuf + cenlen;
/* Initialize zip file data structures based on the total number
* of central directory entries as stored in ENDTOT. Since this
* is a 2-byte field, but we (and other zip implementations)
* support approx. 2**31 entries, we do not trust ENDTOT, but
* treat it only as a strong hint. When we call ourselves
* recursively, knownTotal will have the "true" value.
*
* Keep this path alive even with the Zip64 END support added, just
* for zip files that have more than 0xffff entries but don't have
* the Zip64 enabled.
*/
total = (knownTotal != -1) ? knownTotal : total;
entries = zip->entries = calloc(total, sizeof(entries[0]));
tablelen = zip->tablelen = ((total/2) | 1); // Odd -> fewer collisions
table = zip->table = malloc(tablelen * sizeof(table[0]));
if (entries == NULL || table == NULL) goto Catch;
for (j = 0; j < tablelen; j++)
table[j] = ZIP_ENDCHAIN;
/* Iterate through the entries in the central directory */
for (i = 0, cp = cenbuf; cp <= cenend - CENHDR; i++, cp += CENSIZE(cp)) {
/* Following are unsigned 16-bit */
jint method, nlen;
unsigned int hsh;
if (i >= total) {
/* This will only happen if the zip file has an incorrect
* ENDTOT field, which usually means it contains more than
* 65535 entries. */
cenpos = readCEN(zip, countCENHeaders(cenbuf, cenend));
goto Finally;
}
method = CENHOW(cp);
nlen = CENNAM(cp);
if (GETSIG(cp) != CENSIG)
ZIP_FORMAT_ERROR("invalid CEN header (bad signature)");
if (CENFLG(cp) & 1)
ZIP_FORMAT_ERROR("invalid CEN header (encrypted entry)");
if (method != STORED && method != DEFLATED)
ZIP_FORMAT_ERROR("invalid CEN header (bad compression method)");
if (cp + CENHDR + nlen > cenend)
ZIP_FORMAT_ERROR("invalid CEN header (bad header size)");
/* if the entry is metadata add it to our metadata names */
if (isMetaName((char *)cp+CENHDR, nlen))
if (addMetaName(zip, (char *)cp+CENHDR, nlen) != 0)
goto Catch;
/* Record the CEN offset and the name hash in our hash cell. */
entries[i].cenpos = cenpos + (cp - cenbuf);
entries[i].hash = hashN((char *)cp+CENHDR, nlen);
/* Add the entry to the hash table */
hsh = entries[i].hash % tablelen;
entries[i].next = table[hsh];
table[hsh] = i;
}
if (cp != cenend)
ZIP_FORMAT_ERROR("invalid CEN header (bad header size)");
zip->total = i;
goto Finally;
Catch:
freeCEN(zip);
cenpos = -1;
Finally:
#ifdef USE_MMAP
if (!zip->usemmap)
#endif
free(cenbuf);
return cenpos;
}
