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Commit 5a35e220 authored by Android (Google) Code Review's avatar Android (Google) Code Review Committed by The Android Open Source Project
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am 0e034e5a: Merge change 5162 into donut 

Merge commit '0e034e5a9a71e5e196baff630dca796a0e3ed3e2'

* commit '0e034e5a9a71e5e196baff630dca796a0e3ed3e2':
  Preserve file access mode when backing up / restoring files
parents fc486ea2 8068d16d

libs/utils/BackupHelpers.cpp

+89 −13
Original line number Diff line number Diff line
@@ -41,7 +41,43 @@ namespace android { 
#define MAGIC0 0x70616e53 // Snap

#define MAGIC1 0x656c6946 // File



#if 1 // TEST_BACKUP_HELPERS

/*

 * File entity data format (v1):

 *

 *   - 4-byte version number of the metadata, little endian (0x00000001 for v1)

 *   - 12 bytes of metadata

 *   - the file data itself

 *

 * i.e. a 16-byte metadata header followed by the raw file data.  If the

 * restore code does not recognize the metadata version, it can still

 * interpret the file data itself correctly.

 *

 * file_metadata_v1:

 *

 *   - 4 byte version number === 0x00000001 (little endian)

 *   - 4-byte access mode (little-endian)

 *   - undefined (8 bytes)

 */



struct file_metadata_v1 {

    int version;

    int mode;

    int undefined_1;

    int undefined_2;

};



const static int CURRENT_METADATA_VERSION = 1;



// auto-free buffer management object

class StAutoFree {

public:

    StAutoFree(void* buffer) { mBuf = buffer; }

    ~StAutoFree() { free(mBuf); }

private:

    void* mBuf;

};



#if 0 // TEST_BACKUP_HELPERS

#define LOGP(f, x...) printf(f "\n", x)

#else

#define LOGP(x...) LOGD(x)
@@ -181,29 +217,48 @@ write_delete_file(BackupDataWriter* dataStream, const String8& key) 
}



static int

write_update_file(BackupDataWriter* dataStream, int fd, const String8& key,

write_update_file(BackupDataWriter* dataStream, int fd, int mode, const String8& key,

        char const* realFilename)

{

    LOGP("write_update_file %s (%s)\n", realFilename, key.string());

    LOGP("write_update_file %s (%s) : mode 0%o\n", realFilename, key.string(), mode);



    const int bufsize = 4*1024;

    int err;

    int amt;

    int fileSize;

    int bytesLeft;

    file_metadata_v1 metadata;



    char* buf = (char*)malloc(bufsize);

    StAutoFree _autoFree(buf);



    int crc = crc32(0L, Z_NULL, 0);





    bytesLeft = fileSize = lseek(fd, 0, SEEK_END);

    fileSize = lseek(fd, 0, SEEK_END);

    lseek(fd, 0, SEEK_SET);



    if (sizeof(metadata) != 16) {

        LOGE("ERROR: metadata block is the wrong size!");

    }



    bytesLeft = fileSize + sizeof(metadata);

    err = dataStream->WriteEntityHeader(key, bytesLeft);

    if (err != 0) {

        return err;

    }



    // store the file metadata first

    metadata.version = tolel(CURRENT_METADATA_VERSION);

    metadata.mode = tolel(mode);

    metadata.undefined_1 = metadata.undefined_2 = 0;

    err = dataStream->WriteEntityData(&metadata, sizeof(metadata));

    if (err != 0) {

        return err;

    }

    bytesLeft -= sizeof(metadata); // bytesLeft should == fileSize now



    // now store the file content

    while ((amt = read(fd, buf, bufsize)) != 0 && bytesLeft > 0) {

        bytesLeft -= amt;

        if (bytesLeft < 0) {
@@ -232,8 +287,6 @@ write_update_file(BackupDataWriter* dataStream, int fd, const String8& key, 
                " You aren't doing proper locking!", realFilename, fileSize, fileSize-bytesLeft);

    }



    free(buf);



    return NO_ERROR;

}
@@ -241,11 +294,19 @@ static int 
write_update_file(BackupDataWriter* dataStream, const String8& key, char const* realFilename)

{

    int err;

    struct stat st;



    err = stat(realFilename, &st);

    if (err < 0) {

        return errno;

    }



    int fd = open(realFilename, O_RDONLY);

    if (fd == -1) {

        return errno;

    }

    err = write_update_file(dataStream, fd, key, realFilename);



    err = write_update_file(dataStream, fd, st.st_mode, key, realFilename);

    close(fd);

    return err;

}
@@ -257,6 +318,8 @@ compute_crc32(int fd) 
    int amt;



    char* buf = (char*)malloc(bufsize);

    StAutoFree _autoFree(buf);



    int crc = crc32(0L, Z_NULL, 0);



    lseek(fd, 0, SEEK_SET);
@@ -265,8 +328,6 @@ compute_crc32(int fd) 
        crc = crc32(crc, (Bytef*)buf, amt);

    }



    free(buf);



    return crc;

}
@@ -356,7 +417,7 @@ back_up_files(int oldSnapshotFD, BackupDataWriter* dataStream, int newSnapshotFD 
                        g.s.modTime_sec, g.s.modTime_nsec, g.s.mode, g.s.size, g.s.crc32);

                if (f.modTime_sec != g.s.modTime_sec || f.modTime_nsec != g.s.modTime_nsec

                        || f.mode != g.s.mode || f.size != g.s.size || f.crc32 != g.s.crc32) {

                    write_update_file(dataStream, fd, p, g.file.string());

                    write_update_file(dataStream, fd, g.s.mode, p, g.file.string());

                }



                close(fd);
@@ -416,8 +477,22 @@ RestoreHelperBase::WriteFile(const String8& filename, BackupDataReader* in) 
        return err;

    }



    // TODO: World readable/writable for now.

    mode = 0666;

    // Get the metadata block off the head of the file entity and use that to

    // set up the output file

    file_metadata_v1 metadata;

    amt = in->ReadEntityData(&metadata, sizeof(metadata));

    if (amt != sizeof(metadata)) {

        LOGW("Could not read metadata for %s -- %ld / %s", filename.string(),

                (long)amt, strerror(errno));

        return EIO;

    }

    metadata.version = fromlel(metadata.version);

    metadata.mode = fromlel(metadata.mode);

    if (metadata.version > CURRENT_METADATA_VERSION) {

        LOGW("Restoring file with unsupported metadata version %d (currently %d)",

                metadata.version, CURRENT_METADATA_VERSION);

    }

    mode = metadata.mode;



    // Write the file and compute the crc

    crc = crc32(0L, Z_NULL, 0);
@@ -512,6 +587,7 @@ compare_file(const char* path, const unsigned char* data, int len) 
        fprintf(stderr, "malloc(%d) failed\n", len);

        return ENOMEM;

    }

    StAutoFree _autoFree(contents);



    bool sizesMatch = true;

    amt = lseek(fd, 0, SEEK_END);
@@ -843,6 +919,7 @@ test_read_header_and_entity(BackupDataReader& reader, const char* str) 
    int err;

    int bufSize = strlen(str)+1;

    char* buf = (char*)malloc(bufSize);

    StAutoFree _autoFree(buf);

    String8 string;

    int cookie = 0x11111111;

    size_t actualSize;
@@ -904,7 +981,6 @@ finished: 
    if (err != NO_ERROR) {

        fprintf(stderr, "test_read_header_and_entity failed with %s\n", strerror(err));

    }

    free(buf);

    return err;

}