Allow setting an arbitrary alignment for an entry.

The current code only allows the creation of an entry that is 32 bit
aligned.

Bug: 25446938

Change-Id: I6c924df12ef2bc067b3de7789257af7e3db7e904

2 files changed, 156 insertions, 6 deletions

diff --git a/libziparchive/zip_writer.cc b/libziparchive/zip_writer.cc
index f117cc5af..1ebed30b1 100644
--- a/libziparchive/zip_writer.cc
+++ b/libziparchive/zip_writer.cc
@@ -20,12 +20,19 @@
 
 #include <utils/Log.h>
 
+#include <sys/param.h>
+
 #include <cassert>
 #include <cstdio>
 #include <memory>
+#include <vector>
 #include <zlib.h>
 #define DEF_MEM_LEVEL 8                // normally in zutil.h?
 
+#if !defined(powerof2)
+#define powerof2(x) ((((x)-1)&(x))==0)
+#endif
+
 /* Zip compression methods we support */
 enum {
   kCompressStored     = 0,        // no compression
@@ -50,6 +57,12 @@ static const int32_t kInvalidEntryName = -3;
 // An error occurred in zlib.
 static const int32_t kZlibError = -4;
 
+// The start aligned function was called with the aligned flag.
+static const int32_t kInvalidAlign32Flag = -5;
+
+// The alignment parameter is not a power of 2.
+static const int32_t kInvalidAlignment = -6;
+
 static const char* sErrorCodes[] = {
     "Invalid state",
     "IO error",
@@ -102,7 +115,25 @@ int32_t ZipWriter::HandleError(int32_t error_code) {
 }
 
 int32_t ZipWriter::StartEntry(const char* path, size_t flags) {
-  return StartEntryWithTime(path, flags, time_t());
+  uint32_t alignment = 0;
+  if (flags & kAlign32) {
+    flags &= ~kAlign32;
+    alignment = 4;
+  }
+  return StartAlignedEntryWithTime(path, flags, time_t(), alignment);
+}
+
+int32_t ZipWriter::StartAlignedEntry(const char* path, size_t flags, uint32_t alignment) {
+  return StartAlignedEntryWithTime(path, flags, time_t(), alignment);
+}
+
+int32_t ZipWriter::StartEntryWithTime(const char* path, size_t flags, time_t time) {
+  uint32_t alignment = 0;
+  if (flags & kAlign32) {
+    flags &= ~kAlign32;
+    alignment = 4;
+  }
+  return StartAlignedEntryWithTime(path, flags, time, alignment);
 }
 
 static void ExtractTimeAndDate(time_t when, uint16_t* out_time, uint16_t* out_date) {
@@ -126,11 +157,20 @@ static void ExtractTimeAndDate(time_t when, uint16_t* out_time, uint16_t* out_da
   *out_time = ptm->tm_hour << 11 | ptm->tm_min << 5 | ptm->tm_sec >> 1;
 }
 
-int32_t ZipWriter::StartEntryWithTime(const char* path, size_t flags, time_t time) {
+int32_t ZipWriter::StartAlignedEntryWithTime(const char* path, size_t flags,
+                                             time_t time, uint32_t alignment) {
   if (state_ != State::kWritingZip) {
     return kInvalidState;
   }
 
+  if (flags & kAlign32) {
+    return kInvalidAlign32Flag;
+  }
+
+  if (powerof2(alignment) == 0) {
+    return kInvalidAlignment;
+  }
+
   FileInfo fileInfo = {};
   fileInfo.path = std::string(path);
   fileInfo.local_file_header_offset = current_offset_;
@@ -166,11 +206,14 @@ int32_t ZipWriter::StartEntryWithTime(const char* path, size_t flags, time_t tim
   header.file_name_length = fileInfo.path.size();
 
   off64_t offset = current_offset_ + sizeof(header) + fileInfo.path.size();
-  if ((flags & ZipWriter::kAlign32) && (offset & 0x03)) {
+  std::vector<char> zero_padding;
+  if (alignment != 0 && (offset & (alignment - 1))) {
     // Pad the extra field so the data will be aligned.
-    uint16_t padding = 4 - (offset % 4);
+    uint16_t padding = alignment - (offset % alignment);
     header.extra_field_length = padding;
     offset += padding;
+    zero_padding.resize(padding);
+    memset(zero_padding.data(), 0, zero_padding.size());
   }
 
   if (fwrite(&header, sizeof(header), 1, file_) != 1) {
@@ -181,7 +224,9 @@ int32_t ZipWriter::StartEntryWithTime(const char* path, size_t flags, time_t tim
     return HandleError(kIoError);
   }
 
-  if (fwrite("\0\0\0", 1, header.extra_field_length, file_) != header.extra_field_length) {
+  if (header.extra_field_length != 0 &&
+      fwrite(zero_padding.data(), 1, header.extra_field_length, file_)
+      != header.extra_field_length) {
     return HandleError(kIoError);
   }
 
diff --git a/libziparchive/zip_writer_test.cc b/libziparchive/zip_writer_test.cc
index b7d145833..fe0846db6 100644
--- a/libziparchive/zip_writer_test.cc
+++ b/libziparchive/zip_writer_test.cc
@@ -19,6 +19,7 @@
 
 #include <android-base/test_utils.h>
 #include <gtest/gtest.h>
+#include <time.h>
 #include <memory>
 #include <vector>
 
@@ -122,7 +123,7 @@ TEST_F(zipwriter, WriteUncompressedZipWithMultipleFiles) {
   CloseArchive(handle);
 }
 
-TEST_F(zipwriter, WriteUncompressedZipWithAlignedFile) {
+TEST_F(zipwriter, WriteUncompressedZipFileWithAlignedFlag) {
   ZipWriter writer(file_);
 
   ASSERT_EQ(0, writer.StartEntry("align.txt", ZipWriter::kAlign32));
@@ -142,6 +143,103 @@ TEST_F(zipwriter, WriteUncompressedZipWithAlignedFile) {
   CloseArchive(handle);
 }
 
+void ConvertZipTimeToTm(uint32_t& zip_time, struct tm* tm) {
+  memset(tm, 0, sizeof(struct tm));
+  tm->tm_hour = (zip_time >> 11) & 0x1f;
+  tm->tm_min = (zip_time >> 5) & 0x3f;
+  tm->tm_sec = (zip_time & 0x1f) << 1;
+
+  tm->tm_year = ((zip_time >> 25) & 0x7f) + 80;
+  tm->tm_mon = ((zip_time >> 21) & 0xf) - 1;
+  tm->tm_mday = (zip_time >> 16) & 0x1f;
+}
+
+TEST_F(zipwriter, WriteUncompressedZipFileWithAlignedFlagAndTime) {
+  ZipWriter writer(file_);
+
+  struct tm tm;
+  memset(&tm, 0, sizeof(struct tm));
+  ASSERT_TRUE(strptime("18:30:20 1/12/2001", "%H:%M:%S %d/%m/%Y", &tm) != nullptr);
+  time_t time = mktime(&tm);
+  ASSERT_EQ(0, writer.StartEntryWithTime("align.txt", ZipWriter::kAlign32, time));
+  ASSERT_EQ(0, writer.WriteBytes("he", 2));
+  ASSERT_EQ(0, writer.FinishEntry());
+  ASSERT_EQ(0, writer.Finish());
+
+  ASSERT_GE(0, lseek(fd_, 0, SEEK_SET));
+
+  ZipArchiveHandle handle;
+  ASSERT_EQ(0, OpenArchiveFd(fd_, "temp", &handle, false));
+
+  ZipEntry data;
+  ASSERT_EQ(0, FindEntry(handle, ZipString("align.txt"), &data));
+  EXPECT_EQ(0, data.offset & 0x03);
+
+  struct tm mod;
+  ConvertZipTimeToTm(data.mod_time, &mod);
+  EXPECT_EQ(tm.tm_sec, mod.tm_sec);
+  EXPECT_EQ(tm.tm_min, mod.tm_min);
+  EXPECT_EQ(tm.tm_hour, mod.tm_hour);
+  EXPECT_EQ(tm.tm_mday, mod.tm_mday);
+  EXPECT_EQ(tm.tm_mon, mod.tm_mon);
+  EXPECT_EQ(tm.tm_year, mod.tm_year);
+
+  CloseArchive(handle);
+}
+
+TEST_F(zipwriter, WriteUncompressedZipFileWithAlignedValue) {
+  ZipWriter writer(file_);
+
+  ASSERT_EQ(0, writer.StartAlignedEntry("align.txt", 0, 4096));
+  ASSERT_EQ(0, writer.WriteBytes("he", 2));
+  ASSERT_EQ(0, writer.FinishEntry());
+  ASSERT_EQ(0, writer.Finish());
+
+  ASSERT_GE(0, lseek(fd_, 0, SEEK_SET));
+
+  ZipArchiveHandle handle;
+  ASSERT_EQ(0, OpenArchiveFd(fd_, "temp", &handle, false));
+
+  ZipEntry data;
+  ASSERT_EQ(0, FindEntry(handle, ZipString("align.txt"), &data));
+  EXPECT_EQ(0, data.offset & 0xfff);
+
+  CloseArchive(handle);
+}
+
+TEST_F(zipwriter, WriteUncompressedZipFileWithAlignedValueAndTime) {
+  ZipWriter writer(file_);
+
+  struct tm tm;
+  memset(&tm, 0, sizeof(struct tm));
+  ASSERT_TRUE(strptime("18:30:20 1/12/2001", "%H:%M:%S %d/%m/%Y", &tm) != nullptr);
+  time_t time = mktime(&tm);
+  ASSERT_EQ(0, writer.StartAlignedEntryWithTime("align.txt", 0, time, 4096));
+  ASSERT_EQ(0, writer.WriteBytes("he", 2));
+  ASSERT_EQ(0, writer.FinishEntry());
+  ASSERT_EQ(0, writer.Finish());
+
+  ASSERT_GE(0, lseek(fd_, 0, SEEK_SET));
+
+  ZipArchiveHandle handle;
+  ASSERT_EQ(0, OpenArchiveFd(fd_, "temp", &handle, false));
+
+  ZipEntry data;
+  ASSERT_EQ(0, FindEntry(handle, ZipString("align.txt"), &data));
+  EXPECT_EQ(0, data.offset & 0xfff);
+
+  struct tm mod;
+  ConvertZipTimeToTm(data.mod_time, &mod);
+  EXPECT_EQ(tm.tm_sec, mod.tm_sec);
+  EXPECT_EQ(tm.tm_min, mod.tm_min);
+  EXPECT_EQ(tm.tm_hour, mod.tm_hour);
+  EXPECT_EQ(tm.tm_mday, mod.tm_mday);
+  EXPECT_EQ(tm.tm_mon, mod.tm_mon);
+  EXPECT_EQ(tm.tm_year, mod.tm_year);
+
+  CloseArchive(handle);
+}
+
 TEST_F(zipwriter, WriteCompressedZipWithOneFile) {
   ZipWriter writer(file_);
 
@@ -206,3 +304,10 @@ TEST_F(zipwriter, WriteCompressedZipFlushFull) {
 
   CloseArchive(handle);
 }
+
+TEST_F(zipwriter, CheckStartEntryErrors) {
+  ZipWriter writer(file_);
+
+  ASSERT_EQ(-5, writer.StartAlignedEntry("align.txt", ZipWriter::kAlign32, 4096));
+  ASSERT_EQ(-6, writer.StartAlignedEntry("align.txt", 0, 3));
+}