/*
* 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;
}
/*
* Computes and positions at the start of the CEN header, ie. the central
* directory, this will also return the offset if there is a zip file comment
* at the end of the archive, for most cases this would be 0.
*/
static jlong
compute_cen(int fd, Byte *bp)
{
int bytes;
Byte *p;
jlong base_offset;
jlong offset;
char buffer[MINREAD];
p = buffer;
/*
* Read the END Header, which is the starting point for ZIP files.
* (Clearly designed to make writing a zip file easier than reading
* one. Now isn't that precious...)
*/
if ((base_offset = find_end(fd, bp)) == -1) {
return (-1);
}
p = bp;
/*
* There is a historical, but undocumented, ability to allow for
* additional "stuff" to be prepended to the zip/jar file. It seems
* that this has been used to prepend an actual java launcher
* executable to the jar on Windows. Although this is just another
* form of statically linking a small piece of the JVM to the
* application, we choose to continue to support it. Note that no
* guarantees have been made (or should be made) to the customer that
* this will continue to work.
*
* Therefore, calculate the base offset of the zip file (within the
* expanded file) by assuming that the central directory is followed
* immediately by the end record.
*/
if (zip64_present) {
if ((offset = ZIP64_LOCOFF(p)) < (jlong)0) {
return -1;
}
if (JLI_Lseek(fd, offset, SEEK_SET) < (jlong) 0) {
return (-1);
}
if ((bytes = read(fd, buffer, MINREAD)) < 0) {
return (-1);
}
if (GETSIG(buffer) != ZIP64_ENDSIG) {
return -1;
}
if ((offset = ZIP64_ENDOFF(buffer)) < (jlong)0) {
return -1;
}
if (JLI_Lseek(fd, offset, SEEK_SET) < (jlong)0) {
return (-1);
}
p = buffer;
base_offset = base_offset - ZIP64_ENDSIZ(p) - ZIP64_ENDOFF(p) - ZIP64_ENDHDR;
} else {
base_offset = base_offset - ENDSIZ(p) - ENDOFF(p);
/*
* The END Header indicates the start of the Central Directory
* Headers. Remember that the desired Central Directory Header (CEN)
* will almost always be the second one and the first one is a small
* directory entry ("META-INF/"). Keep the code optimized for
* that case.
*
* Seek to the beginning of the Central Directory.
*/
if (JLI_Lseek(fd, base_offset + ENDOFF(p), SEEK_SET) < (jlong) 0) {
return (-1);
}
}
return base_offset;
}
