path: root/modules/libjar/zipwriter/nsZipHeader.cpp

/* This Source Code Form is subject to the terms of the Mozilla Public
 * License, v. 2.0. If a copy of the MPL was not distributed with this
 * file, You can obtain one at http://mozilla.org/MPL/2.0/.
 */

#include "StreamFunctions.h"
#include "nsZipHeader.h"
#include "nsMemory.h"
#include "prtime.h"

#define ZIP_FILE_HEADER_SIGNATURE 0x04034b50
#define ZIP_FILE_HEADER_SIZE 30
#define ZIP_CDS_HEADER_SIGNATURE 0x02014b50
#define ZIP_CDS_HEADER_SIZE 46

#define FLAGS_IS_UTF8 0x800

#define ZIP_EXTENDED_TIMESTAMP_FIELD 0x5455
#define ZIP_EXTENDED_TIMESTAMP_MODTIME 0x01

using namespace mozilla;

/**
 * nsZipHeader represents an entry from a zip file.
 */
NS_IMPL_ISUPPORTS(nsZipHeader, nsIZipEntry)

NS_IMETHODIMP nsZipHeader::GetCompression(uint16_t *aCompression)
{
    NS_ASSERTION(mInited, "Not initalised");

    *aCompression = mMethod;
    return NS_OK;
}

NS_IMETHODIMP nsZipHeader::GetSize(uint32_t *aSize)
{
    NS_ASSERTION(mInited, "Not initalised");

    *aSize = mCSize;
    return NS_OK;
}

NS_IMETHODIMP nsZipHeader::GetRealSize(uint32_t *aRealSize)
{
    NS_ASSERTION(mInited, "Not initalised");

    *aRealSize = mUSize;
    return NS_OK;
}

NS_IMETHODIMP nsZipHeader::GetCRC32(uint32_t *aCRC32)
{
    NS_ASSERTION(mInited, "Not initalised");

    *aCRC32 = mCRC;
    return NS_OK;
}

NS_IMETHODIMP nsZipHeader::GetIsDirectory(bool *aIsDirectory)
{
    NS_ASSERTION(mInited, "Not initalised");

    if (mName.Last() == '/')
        *aIsDirectory = true;
    else
        *aIsDirectory = false;
    return NS_OK;
}

NS_IMETHODIMP nsZipHeader::GetLastModifiedTime(PRTime *aLastModifiedTime)
{
    NS_ASSERTION(mInited, "Not initalised");

    // Try to read timestamp from extra field
    uint16_t blocksize;
    const uint8_t *tsField = GetExtraField(ZIP_EXTENDED_TIMESTAMP_FIELD, false, &blocksize);
    if (tsField && blocksize >= 5) {
        uint32_t pos = 4;
        uint8_t flags;
        flags = READ8(tsField, &pos);
        if (flags & ZIP_EXTENDED_TIMESTAMP_MODTIME) {
            *aLastModifiedTime = (PRTime)(READ32(tsField, &pos))
                                 * PR_USEC_PER_SEC;
            return NS_OK;
        }
    }

    // Use DOS date/time fields
    // Note that on DST shift we can't handle correctly the hour that is valid
    // in both DST zones
    PRExplodedTime time;

    time.tm_usec = 0;

    time.tm_hour = (mTime >> 11) & 0x1F;
    time.tm_min = (mTime >> 5) & 0x3F;
    time.tm_sec = (mTime & 0x1F) * 2;

    time.tm_year = (mDate >> 9) + 1980;
    time.tm_month = ((mDate >> 5) & 0x0F) - 1;
    time.tm_mday = mDate & 0x1F;

    time.tm_params.tp_gmt_offset = 0;
    time.tm_params.tp_dst_offset = 0;

    PR_NormalizeTime(&time, PR_GMTParameters);
    time.tm_params.tp_gmt_offset = PR_LocalTimeParameters(&time).tp_gmt_offset;
    PR_NormalizeTime(&time, PR_GMTParameters);
    time.tm_params.tp_dst_offset = PR_LocalTimeParameters(&time).tp_dst_offset;

    *aLastModifiedTime = PR_ImplodeTime(&time);

    return NS_OK;
}

NS_IMETHODIMP nsZipHeader::GetIsSynthetic(bool *aIsSynthetic)
{
    NS_ASSERTION(mInited, "Not initalised");

    *aIsSynthetic = false;
    return NS_OK;
}

NS_IMETHODIMP nsZipHeader::GetPermissions(uint32_t *aPermissions)
{
    NS_ASSERTION(mInited, "Not initalised");

    // Always give user read access at least, this matches nsIZipReader's behaviour
    *aPermissions = ((mEAttr >> 16) & 0xfff) | 0x100;
    return NS_OK;
}

void nsZipHeader::Init(const nsACString & aPath, PRTime aDate, uint32_t aAttr,
                       uint32_t aOffset)
{
    NS_ASSERTION(!mInited, "Already initalised");

    PRExplodedTime time;
    PR_ExplodeTime(aDate, PR_LocalTimeParameters, &time);

    mTime = time.tm_sec / 2 + (time.tm_min << 5) + (time.tm_hour << 11);
    mDate = time.tm_mday + ((time.tm_month + 1) << 5) +
            ((time.tm_year - 1980) << 9);

    // Store modification timestamp as extra field
    // First fill CDS extra field
    mFieldLength = 9;
    mExtraField = MakeUnique<uint8_t[]>(mFieldLength);
    if (!mExtraField) {
        mFieldLength = 0;
    } else {
        uint32_t pos = 0;
        WRITE16(mExtraField.get(), &pos, ZIP_EXTENDED_TIMESTAMP_FIELD);
        WRITE16(mExtraField.get(), &pos, 5);
        WRITE8(mExtraField.get(), &pos, ZIP_EXTENDED_TIMESTAMP_MODTIME);
        WRITE32(mExtraField.get(), &pos, aDate / PR_USEC_PER_SEC);

        // Fill local extra field
        mLocalExtraField = MakeUnique<uint8_t[]>(mFieldLength);
        if (mLocalExtraField) {
            mLocalFieldLength = mFieldLength;
            memcpy(mLocalExtraField.get(), mExtraField.get(), mLocalFieldLength);
        }
    }

    mEAttr = aAttr;
    mOffset = aOffset;
    mName = aPath;
    mComment = NS_LITERAL_CSTRING("");
    // Claim a UTF-8 path in case it needs it.
    mFlags |= FLAGS_IS_UTF8;
    mInited = true;
}

uint32_t nsZipHeader::GetFileHeaderLength()
{
    return ZIP_FILE_HEADER_SIZE + mName.Length() + mLocalFieldLength;
}

nsresult nsZipHeader::WriteFileHeader(nsIOutputStream *aStream)
{
    NS_ASSERTION(mInited, "Not initalised");

    uint8_t buf[ZIP_FILE_HEADER_SIZE];
    uint32_t pos = 0;
    WRITE32(buf, &pos, ZIP_FILE_HEADER_SIGNATURE);
    WRITE16(buf, &pos, mVersionNeeded);
    WRITE16(buf, &pos, mFlags);
    WRITE16(buf, &pos, mMethod);
    WRITE16(buf, &pos, mTime);
    WRITE16(buf, &pos, mDate);
    WRITE32(buf, &pos, mCRC);
    WRITE32(buf, &pos, mCSize);
    WRITE32(buf, &pos, mUSize);
    WRITE16(buf, &pos, mName.Length());
    WRITE16(buf, &pos, mLocalFieldLength);

    nsresult rv = ZW_WriteData(aStream, (const char *)buf, pos);
    NS_ENSURE_SUCCESS(rv, rv);

    rv = ZW_WriteData(aStream, mName.get(), mName.Length());
    NS_ENSURE_SUCCESS(rv, rv);

    if (mLocalFieldLength)
    {
      rv = ZW_WriteData(aStream, (const char *)mLocalExtraField.get(), mLocalFieldLength);
      NS_ENSURE_SUCCESS(rv, rv);
    }

    return NS_OK;
}

uint32_t nsZipHeader::GetCDSHeaderLength()
{
    return ZIP_CDS_HEADER_SIZE + mName.Length() + mComment.Length() +
           mFieldLength;
}

nsresult nsZipHeader::WriteCDSHeader(nsIOutputStream *aStream)
{
    NS_ASSERTION(mInited, "Not initalised");

    uint8_t buf[ZIP_CDS_HEADER_SIZE];
    uint32_t pos = 0;
    WRITE32(buf, &pos, ZIP_CDS_HEADER_SIGNATURE);
    WRITE16(buf, &pos, mVersionMade);
    WRITE16(buf, &pos, mVersionNeeded);
    WRITE16(buf, &pos, mFlags);
    WRITE16(buf, &pos, mMethod);
    WRITE16(buf, &pos, mTime);
    WRITE16(buf, &pos, mDate);
    WRITE32(buf, &pos, mCRC);
    WRITE32(buf, &pos, mCSize);
    WRITE32(buf, &pos, mUSize);
    WRITE16(buf, &pos, mName.Length());
    WRITE16(buf, &pos, mFieldLength);
    WRITE16(buf, &pos, mComment.Length());
    WRITE16(buf, &pos, mDisk);
    WRITE16(buf, &pos, mIAttr);
    WRITE32(buf, &pos, mEAttr);
    WRITE32(buf, &pos, mOffset);

    nsresult rv = ZW_WriteData(aStream, (const char *)buf, pos);
    NS_ENSURE_SUCCESS(rv, rv);

    rv = ZW_WriteData(aStream, mName.get(), mName.Length());
    NS_ENSURE_SUCCESS(rv, rv);
    if (mExtraField) {
        rv = ZW_WriteData(aStream, (const char *)mExtraField.get(), mFieldLength);
        NS_ENSURE_SUCCESS(rv, rv);
    }
    return ZW_WriteData(aStream, mComment.get(), mComment.Length());
}

nsresult nsZipHeader::ReadCDSHeader(nsIInputStream *stream)
{
    NS_ASSERTION(!mInited, "Already initalised");

    uint8_t buf[ZIP_CDS_HEADER_SIZE];

    nsresult rv = ZW_ReadData(stream, (char *)buf, ZIP_CDS_HEADER_SIZE);
    NS_ENSURE_SUCCESS(rv, rv);

    uint32_t pos = 0;
    uint32_t signature = READ32(buf, &pos);
    if (signature != ZIP_CDS_HEADER_SIGNATURE)
        return NS_ERROR_FILE_CORRUPTED;

    mVersionMade = READ16(buf, &pos);
    mVersionNeeded = READ16(buf, &pos);
    mFlags = READ16(buf, &pos);
    mMethod = READ16(buf, &pos);
    mTime = READ16(buf, &pos);
    mDate = READ16(buf, &pos);
    mCRC = READ32(buf, &pos);
    mCSize = READ32(buf, &pos);
    mUSize = READ32(buf, &pos);
    uint16_t namelength = READ16(buf, &pos);
    mFieldLength = READ16(buf, &pos);
    uint16_t commentlength = READ16(buf, &pos);
    mDisk = READ16(buf, &pos);
    mIAttr = READ16(buf, &pos);
    mEAttr = READ32(buf, &pos);
    mOffset = READ32(buf, &pos);

    if (namelength > 0) {
        auto field = MakeUnique<char[]>(namelength);
        NS_ENSURE_TRUE(field, NS_ERROR_OUT_OF_MEMORY);
        rv = ZW_ReadData(stream, field.get(), namelength);
        NS_ENSURE_SUCCESS(rv, rv);
        mName.Assign(field.get(), namelength);
    }
    else
        mName = NS_LITERAL_CSTRING("");

    if (mFieldLength > 0) {
        mExtraField = MakeUnique<uint8_t[]>(mFieldLength);
        NS_ENSURE_TRUE(mExtraField, NS_ERROR_OUT_OF_MEMORY);
        rv = ZW_ReadData(stream, (char *)mExtraField.get(), mFieldLength);
        NS_ENSURE_SUCCESS(rv, rv);
    }

    if (commentlength > 0) {
        auto field = MakeUnique<char[]>(commentlength);
        NS_ENSURE_TRUE(field, NS_ERROR_OUT_OF_MEMORY);
        rv = ZW_ReadData(stream, field.get(), commentlength);
        NS_ENSURE_SUCCESS(rv, rv);
        mComment.Assign(field.get(), commentlength);
    }
    else
        mComment = NS_LITERAL_CSTRING("");

    mInited = true;
    return NS_OK;
}

const uint8_t * nsZipHeader::GetExtraField(uint16_t aTag, bool aLocal, uint16_t *aBlockSize)
{
    const uint8_t *buf = aLocal ? mLocalExtraField.get() : mExtraField.get();
    uint32_t buflen = aLocal ? mLocalFieldLength : mFieldLength;
    uint32_t pos = 0;
    uint16_t tag, blocksize;

    while (buf && (pos + 4) <= buflen) {
      tag = READ16(buf, &pos);
      blocksize = READ16(buf, &pos);

      if (aTag == tag && (pos + blocksize) <= buflen) {
        *aBlockSize = blocksize;
        return buf + pos - 4;
      }

      pos += blocksize;
    }

    return nullptr;
}

/*
 * Pad extra field to align data starting position to specified size.
 */
nsresult nsZipHeader::PadExtraField(uint32_t aOffset, uint16_t aAlignSize)
{
    uint32_t pad_size;
    uint32_t pa_offset;
    uint32_t pa_end;

    // Check for range and power of 2.
    if (aAlignSize < 2 || aAlignSize > 32768 ||
        (aAlignSize & (aAlignSize - 1)) != 0) {
      return NS_ERROR_INVALID_ARG;
    }

    // Point to current starting data position.
    aOffset += ZIP_FILE_HEADER_SIZE + mName.Length() + mLocalFieldLength;

    // Calculate aligned offset.
    pa_offset = aOffset & ~(aAlignSize - 1);
    pa_end = pa_offset + aAlignSize;
    pad_size = pa_end - aOffset;
    if (pad_size == 0) {
      return NS_OK;
    }

    // Leave enough room(at least 4 bytes) for valid values in extra field.
    while (pad_size < 4) {
      pad_size += aAlignSize;
    }
    // Extra field length is 2 bytes.
    if (mLocalFieldLength + pad_size > 65535) {
      return NS_ERROR_FAILURE;
    }

    UniquePtr<uint8_t[]> field = Move(mLocalExtraField);
    uint32_t pos = mLocalFieldLength;

    mLocalExtraField = MakeUnique<uint8_t[]>(mLocalFieldLength + pad_size);
    memcpy(mLocalExtraField.get(), field.get(), mLocalFieldLength);
    // Use 0xFFFF as tag ID to avoid conflict with other IDs.
    // For more information, please read "Extensible data fields" section in:
    // http://www.pkware.com/documents/casestudies/APPNOTE.TXT
    WRITE16(mLocalExtraField.get(), &pos, 0xFFFF);
    WRITE16(mLocalExtraField.get(), &pos, pad_size - 4);
    memset(mLocalExtraField.get() + pos, 0, pad_size - 4);
    mLocalFieldLength += pad_size;

    return NS_OK;
}