1 files changed, 1022 insertions, 0 deletions

diff --git a/minzip/Zip.cpp b/minzip/Zip.cpp
new file mode 100644
index 000000000..b887b8466
--- /dev/null
+++ b/minzip/Zip.cpp
@@ -0,0 +1,1022 @@
+/*
+ * Copyright 2006 The Android Open Source Project
+ *
+ * Simple Zip file support.
+ */
+#include "safe_iop.h"
+#include "zlib.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <limits.h>
+#include <stdint.h>     // for uintptr_t
+#include <stdlib.h>
+#include <sys/stat.h>   // for S_ISLNK()
+#include <unistd.h>
+
+#include <string>
+
+#include <android-base/logging.h>
+#include <android-base/stringprintf.h>
+#include <assert.h>
+#include <selinux/label.h>
+#include <selinux/selinux.h>
+
+#include "Zip.h"
+#include "Bits.h"
+#include "DirUtil.h"
+
+#define SORT_ENTRIES 1
+
+/*
+ * Offset and length constants (java.util.zip naming convention).
+ */
+enum {
+    CENSIG = 0x02014b50,      // PK12
+    CENHDR = 46,
+
+    CENVEM =  4,
+    CENVER =  6,
+    CENFLG =  8,
+    CENHOW = 10,
+    CENTIM = 12,
+    CENCRC = 16,
+    CENSIZ = 20,
+    CENLEN = 24,
+    CENNAM = 28,
+    CENEXT = 30,
+    CENCOM = 32,
+    CENDSK = 34,
+    CENATT = 36,
+    CENATX = 38,
+    CENOFF = 42,
+
+    ENDSIG = 0x06054b50,     // PK56
+    ENDHDR = 22,
+
+    ENDSUB =  8,
+    ENDTOT = 10,
+    ENDSIZ = 12,
+    ENDOFF = 16,
+    ENDCOM = 20,
+
+    EXTSIG = 0x08074b50,     // PK78
+    EXTHDR = 16,
+
+    EXTCRC =  4,
+    EXTSIZ =  8,
+    EXTLEN = 12,
+
+    LOCSIG = 0x04034b50,      // PK34
+    LOCHDR = 30,
+
+    LOCVER =  4,
+    LOCFLG =  6,
+    LOCHOW =  8,
+    LOCTIM = 10,
+    LOCCRC = 14,
+    LOCSIZ = 18,
+    LOCLEN = 22,
+    LOCNAM = 26,
+    LOCEXT = 28,
+
+    STORED = 0,
+    DEFLATED = 8,
+
+    CENVEM_UNIX = 3 << 8,   // the high byte of CENVEM
+};
+
+
+/*
+ * For debugging, dump the contents of a ZipEntry.
+ */
+#if 0
+static void dumpEntry(const ZipEntry* pEntry)
+{
+    LOGI(" %p '%.*s'\n", pEntry->fileName,pEntry->fileNameLen,pEntry->fileName);
+    LOGI("   off=%u comp=%u uncomp=%u how=%d\n", pEntry->offset,
+        pEntry->compLen, pEntry->uncompLen, pEntry->compression);
+}
+#endif
+
+/*
+ * (This is a mzHashTableLookup callback.)
+ *
+ * Compare two ZipEntry structs, by name.
+ */
+static int hashcmpZipEntry(const void* ventry1, const void* ventry2)
+{
+    const ZipEntry* entry1 = (const ZipEntry*) ventry1;
+    const ZipEntry* entry2 = (const ZipEntry*) ventry2;
+
+    if (entry1->fileNameLen != entry2->fileNameLen)
+        return entry1->fileNameLen - entry2->fileNameLen;
+    return memcmp(entry1->fileName, entry2->fileName, entry1->fileNameLen);
+}
+
+/*
+ * (This is a mzHashTableLookup callback.)
+ *
+ * find a ZipEntry struct by name.
+ */
+static int hashcmpZipName(const void* ventry, const void* vname)
+{
+    const ZipEntry* entry = (const ZipEntry*) ventry;
+    const char* name = (const char*) vname;
+    unsigned int nameLen = strlen(name);
+
+    if (entry->fileNameLen != nameLen)
+        return entry->fileNameLen - nameLen;
+    return memcmp(entry->fileName, name, nameLen);
+}
+
+/*
+ * Compute the hash code for a ZipEntry filename.
+ *
+ * Not expected to be compatible with any other hash function, so we init
+ * to 2 to ensure it doesn't happen to match.
+ */
+static unsigned int computeHash(const char* name, int nameLen)
+{
+    unsigned int hash = 2;
+
+    while (nameLen--)
+        hash = hash * 31 + *name++;
+
+    return hash;
+}
+
+static void addEntryToHashTable(HashTable* pHash, ZipEntry* pEntry)
+{
+    unsigned int itemHash = computeHash(pEntry->fileName, pEntry->fileNameLen);
+    const ZipEntry* found;
+
+    found = (const ZipEntry*)mzHashTableLookup(pHash,
+                itemHash, pEntry, hashcmpZipEntry, true);
+    if (found != pEntry) {
+        LOG(WARNING) << "WARNING: duplicate entry '" << std::string(found->fileName,
+                     found->fileNameLen) << "' in Zip";
+
+        /* keep going */
+    }
+}
+
+static int validFilename(const char *fileName, unsigned int fileNameLen)
+{
+    // Forbid super long filenames.
+    if (fileNameLen >= PATH_MAX) {
+        LOG(WARNING) << "Filename too long (" << fileNameLen << " chatacters)";
+        return 0;
+    }
+
+    // Require all characters to be printable ASCII (no NUL, no UTF-8, etc).
+    unsigned int i;
+    for (i = 0; i < fileNameLen; ++i) {
+        if (fileName[i] < 32 || fileName[i] >= 127) {
+            LOG(WARNING) << android::base::StringPrintf(
+                    "Filename contains invalid character '\%02x'\n", fileName[i]);
+            return 0;
+        }
+    }
+
+    return 1;
+}
+
+/*
+ * Parse the contents of a Zip archive.  After confirming that the file
+ * is in fact a Zip, we scan out the contents of the central directory and
+ * store it in a hash table.
+ *
+ * Returns "true" on success.
+ */
+static bool parseZipArchive(ZipArchive* pArchive)
+{
+    bool result = false;
+    const unsigned char* ptr;
+    unsigned int i, numEntries, cdOffset;
+    unsigned int val;
+
+    /*
+     * The first 4 bytes of the file will either be the local header
+     * signature for the first file (LOCSIG) or, if the archive doesn't
+     * have any files in it, the end-of-central-directory signature (ENDSIG).
+     */
+    val = get4LE(pArchive->addr);
+    if (val == ENDSIG) {
+        LOG(WARNING) << "Found Zip archive, but it looks empty";
+        goto bail;
+    } else if (val != LOCSIG) {
+        LOG(WARNING) << android::base::StringPrintf("Not a Zip archive (found 0x%08x)\n", val);
+        goto bail;
+    }
+
+    /*
+     * Find the EOCD.  We'll find it immediately unless they have a file
+     * comment.
+     */
+    ptr = pArchive->addr + pArchive->length - ENDHDR;
+
+    while (ptr >= (const unsigned char*) pArchive->addr) {
+        if (*ptr == (ENDSIG & 0xff) && get4LE(ptr) == ENDSIG)
+            break;
+        ptr--;
+    }
+    if (ptr < (const unsigned char*) pArchive->addr) {
+        LOG(WARNING) << "Could not find end-of-central-directory in Zip";
+        goto bail;
+    }
+
+    /*
+     * There are two interesting items in the EOCD block: the number of
+     * entries in the file, and the file offset of the start of the
+     * central directory.
+     */
+    numEntries = get2LE(ptr + ENDSUB);
+    cdOffset = get4LE(ptr + ENDOFF);
+
+    LOG(VERBOSE) << "numEntries=" << numEntries << " cdOffset=" << cdOffset;
+    if (numEntries == 0 || cdOffset >= pArchive->length) {
+        LOG(WARNING) << "Invalid entries=" << numEntries << " offset=" << cdOffset
+                     << " (len=" << pArchive->length << ")";
+        goto bail;
+    }
+
+    /*
+     * Create data structures to hold entries.
+     */
+    pArchive->numEntries = numEntries;
+    pArchive->pEntries = (ZipEntry*) calloc(numEntries, sizeof(ZipEntry));
+    pArchive->pHash = mzHashTableCreate(mzHashSize(numEntries), NULL);
+    if (pArchive->pEntries == NULL || pArchive->pHash == NULL)
+        goto bail;
+
+    ptr = pArchive->addr + cdOffset;
+    for (i = 0; i < numEntries; i++) {
+        ZipEntry* pEntry;
+        unsigned int fileNameLen, extraLen, commentLen, localHdrOffset;
+        const unsigned char* localHdr;
+        const char *fileName;
+
+        if (ptr + CENHDR > (const unsigned char*)pArchive->addr + pArchive->length) {
+            LOG(WARNING) << "Ran off the end (at " << i << ")";
+            goto bail;
+        }
+        if (get4LE(ptr) != CENSIG) {
+            LOG(WARNING) << "Missed a central dir sig (at " << i << ")";
+            goto bail;
+        }
+
+        localHdrOffset = get4LE(ptr + CENOFF);
+        fileNameLen = get2LE(ptr + CENNAM);
+        extraLen = get2LE(ptr + CENEXT);
+        commentLen = get2LE(ptr + CENCOM);
+        fileName = (const char*)ptr + CENHDR;
+        if (fileName + fileNameLen > (const char*)pArchive->addr + pArchive->length) {
+            LOG(WARNING) << "Filename ran off the end (at " << i << ")";
+            goto bail;
+        }
+        if (!validFilename(fileName, fileNameLen)) {
+            LOG(WARNING) << "Invalid filename (at " << i << ")";
+            goto bail;
+        }
+
+#if SORT_ENTRIES
+        /* Figure out where this entry should go (binary search).
+         */
+        if (i > 0) {
+            int low, high;
+
+            low = 0;
+            high = i - 1;
+            while (low <= high) {
+                int mid;
+                int diff;
+                int diffLen;
+
+                mid = low + ((high - low) / 2); // avoid overflow
+
+                if (pArchive->pEntries[mid].fileNameLen < fileNameLen) {
+                    diffLen = pArchive->pEntries[mid].fileNameLen;
+                } else {
+                    diffLen = fileNameLen;
+                }
+                diff = strncmp(pArchive->pEntries[mid].fileName, fileName,
+                        diffLen);
+                if (diff == 0) {
+                    diff = pArchive->pEntries[mid].fileNameLen - fileNameLen;
+                }
+                if (diff < 0) {
+                    low = mid + 1;
+                } else if (diff > 0) {
+                    high = mid - 1;
+                } else {
+                    high = mid;
+                    break;
+                }
+            }
+
+            unsigned int target = high + 1;
+            assert(target <= i);
+            if (target != i) {
+                /* It belongs somewhere other than at the end of
+                 * the list.  Make some room at [target].
+                 */
+                memmove(pArchive->pEntries + target + 1,
+                        pArchive->pEntries + target,
+                        (i - target) * sizeof(ZipEntry));
+            }
+            pEntry = &pArchive->pEntries[target];
+        } else {
+            pEntry = &pArchive->pEntries[0];
+        }
+#else
+        pEntry = &pArchive->pEntries[i];
+#endif
+        pEntry->fileNameLen = fileNameLen;
+        pEntry->fileName = fileName;
+
+        pEntry->compLen = get4LE(ptr + CENSIZ);
+        pEntry->uncompLen = get4LE(ptr + CENLEN);
+        pEntry->compression = get2LE(ptr + CENHOW);
+        pEntry->modTime = get4LE(ptr + CENTIM);
+        pEntry->crc32 = get4LE(ptr + CENCRC);
+
+        /* These two are necessary for finding the mode of the file.
+         */
+        pEntry->versionMadeBy = get2LE(ptr + CENVEM);
+        if ((pEntry->versionMadeBy & 0xff00) != 0 &&
+                (pEntry->versionMadeBy & 0xff00) != CENVEM_UNIX)
+        {
+            LOG(WARNING) << android::base::StringPrintf(
+                    "Incompatible \"version made by\": 0x%02x (at %d)\n",
+                    pEntry->versionMadeBy >> 8, i);
+            goto bail;
+        }
+        pEntry->externalFileAttributes = get4LE(ptr + CENATX);
+
+        // Perform pArchive->addr + localHdrOffset, ensuring that it won't
+        // overflow. This is needed because localHdrOffset is untrusted.
+        if (!safe_add((uintptr_t *)&localHdr, (uintptr_t)pArchive->addr,
+            (uintptr_t)localHdrOffset)) {
+            LOG(WARNING) << "Integer overflow adding in parseZipArchive";
+            goto bail;
+        }
+        if ((uintptr_t)localHdr + LOCHDR >
+            (uintptr_t)pArchive->addr + pArchive->length) {
+            LOG(WARNING) << "Bad offset to local header: " << localHdrOffset
+                         << " (at " << i << ")";
+            goto bail;
+        }
+        if (get4LE(localHdr) != LOCSIG) {
+            LOG(WARNING) << "Missed a local header sig (at " << i << ")";
+            goto bail;
+        }
+        pEntry->offset = localHdrOffset + LOCHDR
+            + get2LE(localHdr + LOCNAM) + get2LE(localHdr + LOCEXT);
+        if (!safe_add(NULL, pEntry->offset, pEntry->compLen)) {
+            LOG(WARNING) << "Integer overflow adding in parseZipArchive";
+            goto bail;
+        }
+        if ((size_t)pEntry->offset + pEntry->compLen > pArchive->length) {
+            LOG(WARNING) << "Data ran off the end (at " << i << ")";
+            goto bail;
+        }
+
+#if !SORT_ENTRIES
+        /* Add to hash table; no need to lock here.
+         * Can't do this now if we're sorting, because entries
+         * will move around.
+         */
+        addEntryToHashTable(pArchive->pHash, pEntry);
+#endif
+
+        //dumpEntry(pEntry);
+        ptr += CENHDR + fileNameLen + extraLen + commentLen;
+    }
+
+#if SORT_ENTRIES
+    /* If we're sorting, we have to wait until all entries
+     * are in their final places, otherwise the pointers will
+     * probably point to the wrong things.
+     */
+    for (i = 0; i < numEntries; i++) {
+        /* Add to hash table; no need to lock here.
+         */
+        addEntryToHashTable(pArchive->pHash, &pArchive->pEntries[i]);
+    }
+#endif
+
+    result = true;
+
+bail:
+    if (!result) {
+        mzHashTableFree(pArchive->pHash);
+        pArchive->pHash = NULL;
+    }
+    return result;
+}
+
+/*
+ * Open a Zip archive and scan out the contents.
+ *
+ * The easiest way to do this is to mmap() the whole thing and do the
+ * traditional backward scan for central directory.  Since the EOCD is
+ * a relatively small bit at the end, we should end up only touching a
+ * small set of pages.
+ *
+ * This will be called on non-Zip files, especially during startup, so
+ * we don't want to be too noisy about failures.  (Do we want a "quiet"
+ * flag?)
+ *
+ * On success, we fill out the contents of "pArchive".
+ */
+int mzOpenZipArchive(unsigned char* addr, size_t length, ZipArchive* pArchive)
+{
+    int err;
+
+    if (length < ENDHDR) {
+        err = -1;
+        LOG(WARNING) << "Archive " << pArchive << " is too small to be zip ("
+                     << length << ")";
+        goto bail;
+    }
+
+    pArchive->addr = addr;
+    pArchive->length = length;
+
+    if (!parseZipArchive(pArchive)) {
+        err = -1;
+        LOG(WARNING) << "Parsing archive " << pArchive << " failed";
+        goto bail;
+    }
+
+    err = 0;
+
+bail:
+    if (err != 0)
+        mzCloseZipArchive(pArchive);
+    return err;
+}
+
+/*
+ * Close a ZipArchive, closing the file and freeing the contents.
+ *
+ * NOTE: the ZipArchive may not have been fully created.
+ */
+void mzCloseZipArchive(ZipArchive* pArchive)
+{
+    LOG(VERBOSE) << "Closing archive " << pArchive;
+
+    free(pArchive->pEntries);
+
+    mzHashTableFree(pArchive->pHash);
+
+    pArchive->pHash = NULL;
+    pArchive->pEntries = NULL;
+}
+
+/*
+ * Find a matching entry.
+ *
+ * Returns NULL if no matching entry found.
+ */
+const ZipEntry* mzFindZipEntry(const ZipArchive* pArchive,
+        const char* entryName)
+{
+    unsigned int itemHash = computeHash(entryName, strlen(entryName));
+
+    return (const ZipEntry*)mzHashTableLookup(pArchive->pHash,
+                itemHash, (char*) entryName, hashcmpZipName, false);
+}
+
+/*
+ * Return true if the entry is a symbolic link.
+ */
+static bool mzIsZipEntrySymlink(const ZipEntry* pEntry)
+{
+    if ((pEntry->versionMadeBy & 0xff00) == CENVEM_UNIX) {
+        return S_ISLNK(pEntry->externalFileAttributes >> 16);
+    }
+    return false;
+}
+
+/* Call processFunction on the uncompressed data of a STORED entry.
+ */
+static bool processStoredEntry(const ZipArchive *pArchive,
+    const ZipEntry *pEntry, ProcessZipEntryContentsFunction processFunction,
+    void *cookie)
+{
+    return processFunction(pArchive->addr + pEntry->offset, pEntry->uncompLen, cookie);
+}
+
+static bool processDeflatedEntry(const ZipArchive *pArchive,
+    const ZipEntry *pEntry, ProcessZipEntryContentsFunction processFunction,
+    void *cookie)
+{
+    bool success = false;
+    unsigned long totalOut = 0;
+    unsigned char procBuf[32 * 1024];
+    z_stream zstream;
+    int zerr;
+
+    /*
+     * Initialize the zlib stream.
+     */
+    memset(&zstream, 0, sizeof(zstream));
+    zstream.zalloc = Z_NULL;
+    zstream.zfree = Z_NULL;
+    zstream.opaque = Z_NULL;
+    zstream.next_in = pArchive->addr + pEntry->offset;
+    zstream.avail_in = pEntry->compLen;
+    zstream.next_out = (Bytef*) procBuf;
+    zstream.avail_out = sizeof(procBuf);
+    zstream.data_type = Z_UNKNOWN;
+
+    /*
+     * Use the undocumented "negative window bits" feature to tell zlib
+     * that there's no zlib header waiting for it.
+     */
+    zerr = inflateInit2(&zstream, -MAX_WBITS);
+    if (zerr != Z_OK) {
+        if (zerr == Z_VERSION_ERROR) {
+            LOG(ERROR) << "Installed zlib is not compatible with linked version ("
+                       << ZLIB_VERSION << ")";
+        } else {
+            LOG(ERROR) << "Call to inflateInit2 failed (zerr=" << zerr << ")";
+        }
+        goto bail;
+    }
+
+    /*
+     * Loop while we have data.
+     */
+    do {
+        /* uncompress the data */
+        zerr = inflate(&zstream, Z_NO_FLUSH);
+        if (zerr != Z_OK && zerr != Z_STREAM_END) {
+            LOG(WARNING) << "zlib inflate call failed (zerr=" << zerr << ")";
+            goto z_bail;
+        }
+
+        /* write when we're full or when we're done */
+        if (zstream.avail_out == 0 ||
+            (zerr == Z_STREAM_END && zstream.avail_out != sizeof(procBuf)))
+        {
+            long procSize = zstream.next_out - procBuf;
+            LOG(VERBOSE) << "+++ processing " << procSize << " bytes";
+            bool ret = processFunction(procBuf, procSize, cookie);
+            if (!ret) {
+                LOG(WARNING) << "Process function elected to fail (in inflate)";
+                goto z_bail;
+            }
+
+            zstream.next_out = procBuf;
+            zstream.avail_out = sizeof(procBuf);
+        }
+    } while (zerr == Z_OK);
+
+    assert(zerr == Z_STREAM_END);       /* other errors should've been caught */
+
+    // success!
+    totalOut = zstream.total_out;
+    success = true;
+
+z_bail:
+    inflateEnd(&zstream);        /* free up any allocated structures */
+
+bail:
+    if (totalOut != pEntry->uncompLen) {
+        if (success) {       // error already shown?
+            LOG(WARNING) << "Size mismatch on inflated file (" << totalOut << " vs "
+                         << pEntry->uncompLen << ")";
+        }
+        return false;
+    }
+    return true;
+}
+
+/*
+ * Stream the uncompressed data through the supplied function,
+ * passing cookie to it each time it gets called.  processFunction
+ * may be called more than once.
+ *
+ * If processFunction returns false, the operation is abandoned and
+ * mzProcessZipEntryContents() immediately returns false.
+ *
+ * This is useful for calculating the hash of an entry's uncompressed contents.
+ */
+bool mzProcessZipEntryContents(const ZipArchive *pArchive,
+    const ZipEntry *pEntry, ProcessZipEntryContentsFunction processFunction,
+    void *cookie)
+{
+    bool ret = false;
+
+    switch (pEntry->compression) {
+    case STORED:
+        ret = processStoredEntry(pArchive, pEntry, processFunction, cookie);
+        break;
+    case DEFLATED:
+        ret = processDeflatedEntry(pArchive, pEntry, processFunction, cookie);
+        break;
+    default:
+        LOG(ERROR) << "Unsupported compression type " << pEntry->compression
+                   << " for entry '" << pEntry->fileName << "'";
+        break;
+    }
+
+    return ret;
+}
+
+typedef struct {
+    char *buf;
+    int bufLen;
+} CopyProcessArgs;
+
+static bool copyProcessFunction(const unsigned char *data, int dataLen,
+        void *cookie)
+{
+    CopyProcessArgs *args = (CopyProcessArgs *)cookie;
+    if (dataLen <= args->bufLen) {
+        memcpy(args->buf, data, dataLen);
+        args->buf += dataLen;
+        args->bufLen -= dataLen;
+        return true;
+    }
+    return false;
+}
+
+/*
+ * Read an entry into a buffer allocated by the caller.
+ */
+bool mzReadZipEntry(const ZipArchive* pArchive, const ZipEntry* pEntry,
+        char *buf, int bufLen)
+{
+    CopyProcessArgs args;
+    bool ret;
+
+    args.buf = buf;
+    args.bufLen = bufLen;
+    ret = mzProcessZipEntryContents(pArchive, pEntry, copyProcessFunction,
+            (void *)&args);
+    if (!ret) {
+        LOG(ERROR) << "Can't extract entry to buffer";
+        return false;
+    }
+    return true;
+}
+
+static bool writeProcessFunction(const unsigned char *data, int dataLen,
+                                 void *cookie)
+{
+    int fd = (int)(intptr_t)cookie;
+    if (dataLen == 0) {
+        return true;
+    }
+    ssize_t soFar = 0;
+    while (true) {
+        ssize_t n = TEMP_FAILURE_RETRY(write(fd, data+soFar, dataLen-soFar));
+        if (n <= 0) {
+            PLOG(ERROR) << "Error writing " << dataLen-soFar << " bytes from zip file from "
+                        << data+soFar;
+            return false;
+        } else if (n > 0) {
+            soFar += n;
+            if (soFar == dataLen) return true;
+            if (soFar > dataLen) {
+                LOG(ERROR) << "write overrun?  (" << soFar << " bytes instead of "
+                           << dataLen << ")";
+                return false;
+            }
+        }
+    }
+}
+
+/*
+ * Uncompress "pEntry" in "pArchive" to "fd" at the current offset.
+ */
+bool mzExtractZipEntryToFile(const ZipArchive *pArchive,
+    const ZipEntry *pEntry, int fd)
+{
+    bool ret = mzProcessZipEntryContents(pArchive, pEntry, writeProcessFunction,
+                                         (void*)(intptr_t)fd);
+    if (!ret) {
+        LOG(ERROR) << "Can't extract entry to file.";
+        return false;
+    }
+    return true;
+}
+
+typedef struct {
+    unsigned char* buffer;
+    long len;
+} BufferExtractCookie;
+
+static bool bufferProcessFunction(const unsigned char *data, int dataLen,
+    void *cookie) {
+    BufferExtractCookie *bec = (BufferExtractCookie*)cookie;
+
+    memmove(bec->buffer, data, dataLen);
+    bec->buffer += dataLen;
+    bec->len -= dataLen;
+
+    return true;
+}
+
+/*
+ * Uncompress "pEntry" in "pArchive" to buffer, which must be large
+ * enough to hold mzGetZipEntryUncomplen(pEntry) bytes.
+ */
+bool mzExtractZipEntryToBuffer(const ZipArchive *pArchive,
+    const ZipEntry *pEntry, unsigned char *buffer)
+{
+    BufferExtractCookie bec;
+    bec.buffer = buffer;
+    bec.len = mzGetZipEntryUncompLen(pEntry);
+
+    bool ret = mzProcessZipEntryContents(pArchive, pEntry,
+        bufferProcessFunction, (void*)&bec);
+    if (!ret || bec.len != 0) {
+        LOG(ERROR) << "Can't extract entry to memory buffer.";
+        return false;
+    }
+    return true;
+}
+
+
+/* Helper state to make path translation easier and less malloc-happy.
+ */
+typedef struct {
+    const char *targetDir;
+    const char *zipDir;
+    char *buf;
+    int targetDirLen;
+    int zipDirLen;
+    int bufLen;
+} MzPathHelper;
+
+/* Given the values of targetDir and zipDir in the helper,
+ * return the target filename of the provided entry.
+ * The helper must be initialized first.
+ */
+static const char *targetEntryPath(MzPathHelper *helper, ZipEntry *pEntry)
+{
+    int needLen;
+    bool firstTime = (helper->buf == NULL);
+
+    /* target file <-- targetDir + / + entry[zipDirLen:]
+     */
+    needLen = helper->targetDirLen + 1 +
+            pEntry->fileNameLen - helper->zipDirLen + 1;
+    if (firstTime || needLen > helper->bufLen) {
+        char *newBuf;
+
+        needLen *= 2;
+        newBuf = (char *)realloc(helper->buf, needLen);
+        if (newBuf == NULL) {
+            return NULL;
+        }
+        helper->buf = newBuf;
+        helper->bufLen = needLen;
+    }
+
+    /* Every path will start with the target path and a slash.
+     */
+    if (firstTime) {
+        char *p = helper->buf;
+        memcpy(p, helper->targetDir, helper->targetDirLen);
+        p += helper->targetDirLen;
+        if (p == helper->buf || p[-1] != '/') {
+            helper->targetDirLen += 1;
+            *p++ = '/';
+        }
+    }
+
+    /* Replace the custom part of the path with the appropriate
+     * part of the entry's path.
+     */
+    char *epath = helper->buf + helper->targetDirLen;
+    memcpy(epath, pEntry->fileName + helper->zipDirLen,
+            pEntry->fileNameLen - helper->zipDirLen);
+    epath += pEntry->fileNameLen - helper->zipDirLen;
+    *epath = '\0';
+
+    return helper->buf;
+}
+
+/*
+ * Inflate all entries under zipDir to the directory specified by
+ * targetDir, which must exist and be a writable directory.
+ *
+ * The immediate children of zipDir will become the immediate
+ * children of targetDir; e.g., if the archive contains the entries
+ *
+ *     a/b/c/one
+ *     a/b/c/two
+ *     a/b/c/d/three
+ *
+ * and mzExtractRecursive(a, "a/b/c", "/tmp") is called, the resulting
+ * files will be
+ *
+ *     /tmp/one
+ *     /tmp/two
+ *     /tmp/d/three
+ *
+ * Returns true on success, false on failure.
+ */
+bool mzExtractRecursive(const ZipArchive *pArchive,
+                        const char *zipDir, const char *targetDir,
+                        const struct utimbuf *timestamp,
+                        void (*callback)(const char *fn, void *), void *cookie,
+                        struct selabel_handle *sehnd)
+{
+    if (zipDir[0] == '/') {
+        LOG(ERROR) << "mzExtractRecursive(): zipDir must be a relative path.";
+        return false;
+    }
+    if (targetDir[0] != '/') {
+        LOG(ERROR) << "mzExtractRecursive(): targetDir must be an absolute path.\n";
+        return false;
+    }
+
+    unsigned int zipDirLen;
+    char *zpath;
+
+    zipDirLen = strlen(zipDir);
+    zpath = (char *)malloc(zipDirLen + 2);
+    if (zpath == NULL) {
+        LOG(ERROR) << "Can't allocate " << (zipDirLen + 2) << " bytes for zip path";
+        return false;
+    }
+    /* If zipDir is empty, we'll extract the entire zip file.
+     * Otherwise, canonicalize the path.
+     */
+    if (zipDirLen > 0) {
+        /* Make sure there's (hopefully, exactly one) slash at the
+         * end of the path.  This way we don't need to worry about
+         * accidentally extracting "one/twothree" when a path like
+         * "one/two" is specified.
+         */
+        memcpy(zpath, zipDir, zipDirLen);
+        if (zpath[zipDirLen-1] != '/') {
+            zpath[zipDirLen++] = '/';
+        }
+    }
+    zpath[zipDirLen] = '\0';
+
+    /* Set up the helper structure that we'll use to assemble paths.
+     */
+    MzPathHelper helper;
+    helper.targetDir = targetDir;
+    helper.targetDirLen = strlen(helper.targetDir);
+    helper.zipDir = zpath;
+    helper.zipDirLen = strlen(helper.zipDir);
+    helper.buf = NULL;
+    helper.bufLen = 0;
+
+    /* Walk through the entries and extract anything whose path begins
+     * with zpath.
+    //TODO: since the entries are sorted, binary search for the first match
+    //      and stop after the first non-match.
+     */
+    unsigned int i;
+    bool seenMatch = false;
+    int ok = true;
+    int extractCount = 0;
+    for (i = 0; i < pArchive->numEntries; i++) {
+        ZipEntry *pEntry = pArchive->pEntries + i;
+        if (pEntry->fileNameLen < zipDirLen) {
+       //TODO: look out for a single empty directory entry that matches zpath, but
+       //      missing the trailing slash.  Most zip files seem to include
+       //      the trailing slash, but I think it's legal to leave it off.
+       //      e.g., zpath "a/b/", entry "a/b", with no children of the entry.
+            /* No chance of matching.
+             */
+#if SORT_ENTRIES
+            if (seenMatch) {
+                /* Since the entries are sorted, we can give up
+                 * on the first mismatch after the first match.
+                 */
+                break;
+            }
+#endif
+            continue;
+        }
+        /* If zpath is empty, this strncmp() will match everything,
+         * which is what we want.
+         */
+        if (strncmp(pEntry->fileName, zpath, zipDirLen) != 0) {
+#if SORT_ENTRIES
+            if (seenMatch) {
+                /* Since the entries are sorted, we can give up
+                 * on the first mismatch after the first match.
+                 */
+                break;
+            }
+#endif
+            continue;
+        }
+        /* This entry begins with zipDir, so we'll extract it.
+         */
+        seenMatch = true;
+
+        /* Find the target location of the entry.
+         */
+        const char *targetFile = targetEntryPath(&helper, pEntry);
+        if (targetFile == NULL) {
+            LOG(ERROR) << "Can't assemble target path for \"" << std::string(pEntry->fileName,
+                       pEntry->fileNameLen) << "\"";
+            ok = false;
+            break;
+        }
+
+#define UNZIP_DIRMODE 0755
+#define UNZIP_FILEMODE 0644
+        /*
+         * Create the file or directory. We ignore directory entries
+         * because we recursively create paths to each file entry we encounter
+         * in the zip archive anyway.
+         *
+         * NOTE: A "directory entry" in a zip archive is just a zero length
+         * entry that ends in a "/". They're not mandatory and many tools get
+         * rid of them. We need to process them only if we want to preserve
+         * empty directories from the archive.
+         */
+        if (pEntry->fileName[pEntry->fileNameLen-1] != '/') {
+            /* This is not a directory.  First, make sure that
+             * the containing directory exists.
+             */
+            int ret = dirCreateHierarchy(
+                    targetFile, UNZIP_DIRMODE, timestamp, true, sehnd);
+            if (ret != 0) {
+                PLOG(ERROR) << "Can't create containing directory for \"" << targetFile << "\"";
+                ok = false;
+                break;
+            }
+
+            /*
+             * The entry is a regular file or a symlink. Open the target for writing.
+             *
+             * TODO: This behavior for symlinks seems rather bizarre. For a
+             * symlink foo/bar/baz -> foo/tar/taz, we will create a file called
+             * "foo/bar/baz" whose contents are the literal "foo/tar/taz". We
+             * warn about this for now and preserve older behavior.
+             */
+            if (mzIsZipEntrySymlink(pEntry)) {
+                LOG(ERROR) << "Symlink entry \"" << std::string(pEntry->fileName,
+                           pEntry->fileNameLen) << "\" will be output as a regular file.";
+            }
+
+            char *secontext = NULL;
+
+            if (sehnd) {
+                selabel_lookup(sehnd, &secontext, targetFile, UNZIP_FILEMODE);
+                setfscreatecon(secontext);
+            }
+
+            int fd = open(targetFile, O_CREAT|O_WRONLY|O_TRUNC,
+                UNZIP_FILEMODE);
+
+            if (secontext) {
+                freecon(secontext);
+                setfscreatecon(NULL);
+            }
+
+            if (fd < 0) {
+                PLOG(ERROR) << "Can't create target file \"" << targetFile << "\"";
+                ok = false;
+                break;
+            }
+
+            bool ok = mzExtractZipEntryToFile(pArchive, pEntry, fd);
+            if (ok) {
+                ok = (fsync(fd) == 0);
+            }
+            if (close(fd) != 0) {
+                ok = false;
+            }
+            if (!ok) {
+                LOG(ERROR) << "Error extracting \"" << targetFile << "\"";
+                ok = false;
+                break;
+            }
+
+            if (timestamp != NULL && utime(targetFile, timestamp)) {
+                LOG(ERROR) << "Error touching \"" << targetFile << "\"";
+                ok = false;
+                break;
+            }
+
+            LOG(VERBOSE) <<"Extracted file \"" << targetFile << "\"";
+            ++extractCount;
+        }
+
+        if (callback != NULL) callback(targetFile, cookie);
+    }
+
+    LOG(VERBOSE) << "Extracted " << extractCount << " file(s)";
+
+    free(helper.buf);
+    free(zpath);
+
+    return ok;
+}