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Commit a456c213 authored by Tao Bao's avatar Tao Bao
Browse files

ziparchive: Allow ExtractEntryToFile() to work with block device. 

FileWriter::Create() calls ftruncate(2) to truncate the destination
file, which doesn't work with FD that references a block device. It
leads to kIoError when calling ExtractEntryToFile() to extract an entry
to block device FD.

As a result, it fails the package_extract_file() command in OTA updates
(e.g. 'package_extract_file("boot.img",
"/dev/block/platform/soc.0/f9824900.sdhci/by-name/boot")').

This CL skips the call to ftruncate(2) if FD references a block device.

Bug: 32903624
Test: ziparchive-tests works.
Test: Build an OTA updater (m updater) and call package_extract_file().

Change-Id: Ia81116f1a8d7cab802396bdc32c6096b4cb56a3c
parent 55735986

include/ziparchive/zip_archive.h

+2 −1
Original line number Diff line number Diff line
@@ -195,7 +195,8 @@ void EndIteration(void* cookie); 
 * Uncompress and write an entry to an open file identified by |fd|.

 * |entry->uncompressed_length| bytes will be written to the file at

 * its current offset, and the file will be truncated at the end of

 * the uncompressed data.

 * the uncompressed data (no truncation if |fd| references a block

 * device).

 *

 * Returns 0 on success and negative values on failure.

 */

libziparchive/zip_archive.cc

+15 −5
Original line number Diff line number Diff line
@@ -781,7 +781,8 @@ class FileWriter : public Writer { 
  // Creates a FileWriter for |fd| and prepare to write |entry| to it,

  // guaranteeing that the file descriptor is valid and that there's enough

  // space on the volume to write out the entry completely and that the file

  // is truncated to the correct length.

  // is truncated to the correct length (no truncation if |fd| references a

  // block device).

  //

  // Returns a valid FileWriter on success, |nullptr| if an error occurred.

  static std::unique_ptr<FileWriter> Create(int fd, const ZipEntry* entry) {
@@ -814,12 +815,21 @@ class FileWriter : public Writer { 
    }

#endif  // __linux__



    struct stat sb;

    if (fstat(fd, &sb) == -1) {

      ALOGW("Zip: unable to fstat file: %s", strerror(errno));

      return std::unique_ptr<FileWriter>(nullptr);

    }



    // Block device doesn't support ftruncate(2).

    if (!S_ISBLK(sb.st_mode)) {

      result = TEMP_FAILURE_RETRY(ftruncate(fd, declared_length + current_offset));

      if (result == -1) {

        ALOGW("Zip: unable to truncate file to %" PRId64 ": %s",

              static_cast<int64_t>(declared_length + current_offset), strerror(errno));

        return std::unique_ptr<FileWriter>(nullptr);

      }

    }



    return std::unique_ptr<FileWriter>(new FileWriter(fd, declared_length));

  }