Android/frameworks_base
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Merge change 5162 into donut

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* changes:
  Preserve file access mode when backing up / restoring files
This commit is contained in:
Android (Google) Code Review
2009-06-24 11:18:01 -07:00
parent 6f8e592347 fbb92385f2
commit 0e034e5a9a
1 changed files with 89 additions and 13 deletions
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102
libs/utils/BackupHelpers.cpp
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@@ -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;
}