Add the backup data file writer C++ class.
diff --git a/include/utils/backup_helpers.h b/include/utils/backup_helpers.h
index 73b9989..0c59fec 100644
--- a/include/utils/backup_helpers.h
+++ b/include/utils/backup_helpers.h
@@ -25,8 +25,28 @@
int back_up_files(int oldSnapshotFD, int oldDataStream, int newSnapshotFD,
char const* fileBase, char const* const* files, int fileCount);
+// the sizes of all of these match.
+typedef struct {
+ int type; // == APP_MAGIC_V1
+ int packageLen; // length of the name of the package that follows, not including the null.
+ int cookie;
+} app_header_v1;
+
+typedef struct {
+ int type; // ENTITY_MAGIC_V1
+ int keyLen; // length of the key name, not including the null terminator
+ int dataSize; // size of the data, not including the padding
+} entity_header_v1;
+
+typedef struct {
+ int type; // FOOTER_MAGIC_V1
+ int entityCount; // the number of entities that were written
+ int cookie;
+} app_footer_v1;
+
+
/**
- * Reads the data.
+ * Writes the data.
*
* If an error occurs, it poisons this object and all write calls will fail
* with the error that occurred.
@@ -38,12 +58,12 @@
// does not close fd
~BackupDataWriter();
- status_t WriteAppHeader(const String8& packageName);
+ status_t WriteAppHeader(const String8& packageName, int cookie);
status_t WriteEntityHeader(const String8& key, size_t dataSize);
status_t WriteEntityData(const void* data, size_t size);
- status_t WriteAppFooter();
+ status_t WriteAppFooter(int cookie);
private:
explicit BackupDataWriter();
@@ -55,6 +75,44 @@
int m_entityCount;
};
+/**
+ * Reads the data.
+ *
+ * If an error occurs, it poisons this object and all write calls will fail
+ * with the error that occurred.
+ */
+class BackupDataReader
+{
+public:
+ BackupDataReader(int fd);
+ // does not close fd
+ ~BackupDataReader();
+
+ status_t Status();
+ status_t ReadNextHeader();
+
+ status_t ReadAppHeader(String8* packageName, int* cookie);
+ bool HasEntities();
+ status_t ReadEntityHeader(String8* key, size_t* dataSize);
+ status_t ReadEntityData(void* data, size_t size);
+ status_t ReadAppFooter(int* cookie);
+
+private:
+ explicit BackupDataReader();
+ status_t skip_padding();
+
+ int m_fd;
+ status_t m_status;
+ ssize_t m_pos;
+ int m_entityCount;
+ union {
+ int type;
+ app_header_v1 app;
+ entity_header_v1 entity;
+ app_footer_v1 footer;
+ } m_header;
+};
+
#define TEST_BACKUP_HELPERS 0
#if TEST_BACKUP_HELPERS
@@ -62,6 +120,7 @@
int backup_helper_test_four();
int backup_helper_test_files();
int backup_helper_test_data_writer();
+int backup_helper_test_data_reader();
#endif
} // namespace android
diff --git a/libs/utils/backup_data.cpp b/libs/utils/backup_data.cpp
index c7f1fdb..dd04449 100644
--- a/libs/utils/backup_data.cpp
+++ b/libs/utils/backup_data.cpp
@@ -14,12 +14,16 @@
* limitations under the License.
*/
+#define LOG_TAG "backup_data"
+
#include <utils/backup_helpers.h>
#include <utils/ByteOrder.h>
#include <stdio.h>
#include <unistd.h>
+#include <cutils/log.h>
+
namespace android {
/*
@@ -39,22 +43,6 @@
#define ENTITY_MAGIC_V1 0x61746144 // Data (little endian)
#define FOOTER_MAGIC_V1 0x746f6f46 // Foot (little endian)
-typedef struct {
- int type; // == APP_MAGIC_V1
- int packageLen; // length of the name of the package that follows, not including the null.
-} app_header_v1;
-
-typedef struct {
- int type; // ENTITY_MAGIC_V1
- int keyLen; // length of the key name, not including the null terminator
- int dataSize; // size of the data, not including the padding
-} entity_header_v1;
-
-typedef struct {
- int type; // FOOTER_MAGIC_V1
- int entityCount; // the number of entities that were written
-} app_footer_v1;
-
const static int ROUND_UP[4] = { 0, 3, 2, 1 };
static inline size_t
@@ -102,7 +90,7 @@
}
status_t
-BackupDataWriter::WriteAppHeader(const String8& packageName)
+BackupDataWriter::WriteAppHeader(const String8& packageName, int cookie)
{
if (m_status != NO_ERROR) {
return m_status;
@@ -122,6 +110,7 @@
header.type = tolel(APP_MAGIC_V1);
header.packageLen = tolel(nameLen);
+ header.cookie = cookie;
amt = write(m_fd, &header, sizeof(app_header_v1));
if (amt != sizeof(app_header_v1)) {
@@ -204,7 +193,7 @@
}
status_t
-BackupDataWriter::WriteAppFooter()
+BackupDataWriter::WriteAppFooter(int cookie)
{
if (m_status != NO_ERROR) {
return m_status;
@@ -222,6 +211,7 @@
footer.type = tolel(FOOTER_MAGIC_V1);
footer.entityCount = tolel(m_entityCount);
+ footer.cookie = cookie;
amt = write(m_fd, &footer, sizeof(app_footer_v1));
if (amt != sizeof(app_footer_v1)) {
@@ -233,4 +223,206 @@
return NO_ERROR;
}
+
+BackupDataReader::BackupDataReader(int fd)
+ :m_fd(fd),
+ m_status(NO_ERROR),
+ m_pos(0),
+ m_entityCount(0)
+{
+ memset(&m_header, 0, sizeof(m_header));
+}
+
+BackupDataReader::~BackupDataReader()
+{
+}
+
+status_t
+BackupDataReader::Status()
+{
+ return m_status;
+}
+
+#define CHECK_SIZE(actual, expected) \
+ do { \
+ if ((actual) != (expected)) { \
+ if ((actual) == 0) { \
+ m_status = EIO; \
+ } else { \
+ m_status = errno; \
+ } \
+ return m_status; \
+ } \
+ } while(0)
+#define SKIP_PADDING() \
+ do { \
+ status_t err = skip_padding(); \
+ if (err != NO_ERROR) { \
+ m_status = err; \
+ return err; \
+ } \
+ } while(0)
+
+status_t
+BackupDataReader::ReadNextHeader()
+{
+ if (m_status != NO_ERROR) {
+ return m_status;
+ }
+
+ int amt;
+
+ SKIP_PADDING();
+ amt = read(m_fd, &m_header, sizeof(m_header));
+ CHECK_SIZE(amt, sizeof(m_header));
+
+ // validate and fix up the fields.
+ m_header.type = fromlel(m_header.type);
+ switch (m_header.type)
+ {
+ case APP_MAGIC_V1:
+ m_header.app.packageLen = fromlel(m_header.app.packageLen);
+ if (m_header.app.packageLen < 0) {
+ LOGD("App header at %d has packageLen<0: 0x%08x\n", (int)m_pos,
+ (int)m_header.app.packageLen);
+ m_status = EINVAL;
+ }
+ m_header.app.cookie = m_header.app.cookie;
+ break;
+ case ENTITY_MAGIC_V1:
+ m_header.entity.keyLen = fromlel(m_header.entity.keyLen);
+ if (m_header.entity.keyLen <= 0) {
+ LOGD("Entity header at %d has keyLen<=0: 0x%08x\n", (int)m_pos,
+ (int)m_header.entity.keyLen);
+ m_status = EINVAL;
+ }
+ m_header.entity.dataSize = fromlel(m_header.entity.dataSize);
+ if (m_header.entity.dataSize < 0) {
+ LOGD("Entity header at %d has dataSize<0: 0x%08x\n", (int)m_pos,
+ (int)m_header.entity.dataSize);
+ m_status = EINVAL;
+ }
+ m_entityCount++;
+ break;
+ case FOOTER_MAGIC_V1:
+ m_header.footer.entityCount = fromlel(m_header.footer.entityCount);
+ if (m_header.footer.entityCount < 0) {
+ LOGD("Entity header at %d has entityCount<0: 0x%08x\n", (int)m_pos,
+ (int)m_header.footer.entityCount);
+ m_status = EINVAL;
+ }
+ m_header.footer.cookie = m_header.footer.cookie;
+ break;
+ default:
+ LOGD("Chunk header at %d has invalid type: 0x%08x", (int)m_pos, (int)m_header.type);
+ m_status = EINVAL;
+ }
+ m_pos += sizeof(m_header);
+
+ return m_status;
+}
+
+status_t
+BackupDataReader::ReadAppHeader(String8* packageName, int* cookie)
+{
+ if (m_status != NO_ERROR) {
+ return m_status;
+ }
+ if (m_header.type != APP_MAGIC_V1) {
+ return EINVAL;
+ }
+ size_t size = m_header.app.packageLen;
+ char* buf = packageName->lockBuffer(size);
+ if (packageName == NULL) {
+ packageName->unlockBuffer();
+ m_status = ENOMEM;
+ return m_status;
+ }
+ int amt = read(m_fd, buf, size+1);
+ CHECK_SIZE(amt, (int)size+1);
+ packageName->unlockBuffer(size);
+ m_pos += size+1;
+ *cookie = m_header.app.cookie;
+ return NO_ERROR;
+}
+
+bool
+BackupDataReader::HasEntities()
+{
+ return m_status == NO_ERROR && m_header.type == ENTITY_MAGIC_V1;
+}
+
+status_t
+BackupDataReader::ReadEntityHeader(String8* key, size_t* dataSize)
+{
+ if (m_status != NO_ERROR) {
+ return m_status;
+ }
+ if (m_header.type != ENTITY_MAGIC_V1) {
+ return EINVAL;
+ }
+ size_t size = m_header.app.packageLen;
+ char* buf = key->lockBuffer(size);
+ if (key == NULL) {
+ key->unlockBuffer();
+ m_status = ENOMEM;
+ return m_status;
+ }
+ int amt = read(m_fd, buf, size+1);
+ CHECK_SIZE(amt, (int)size+1);
+ key->unlockBuffer(size);
+ m_pos += size+1;
+ *dataSize = m_header.entity.dataSize;
+ SKIP_PADDING();
+ return NO_ERROR;
+}
+
+status_t
+BackupDataReader::ReadEntityData(void* data, size_t size)
+{
+ if (m_status != NO_ERROR) {
+ return m_status;
+ }
+ int amt = read(m_fd, data, size);
+ CHECK_SIZE(amt, (int)size);
+ m_pos += size;
+ return NO_ERROR;
+}
+
+status_t
+BackupDataReader::ReadAppFooter(int* cookie)
+{
+ if (m_status != NO_ERROR) {
+ return m_status;
+ }
+ if (m_header.type != FOOTER_MAGIC_V1) {
+ return EINVAL;
+ }
+ if (m_header.footer.entityCount != m_entityCount) {
+ LOGD("entity count mismatch actual=%d expected=%d", m_entityCount,
+ m_header.footer.entityCount);
+ m_status = EINVAL;
+ return m_status;
+ }
+ *cookie = m_header.footer.cookie;
+ return NO_ERROR;
+}
+
+status_t
+BackupDataReader::skip_padding()
+{
+ ssize_t amt;
+ ssize_t paddingSize;
+
+ paddingSize = padding_extra(m_pos);
+ if (paddingSize > 0) {
+ uint32_t padding;
+ amt = read(m_fd, &padding, paddingSize);
+ CHECK_SIZE(amt, paddingSize);
+ m_pos += amt;
+ }
+ return NO_ERROR;
+}
+
+
} // namespace android
diff --git a/libs/utils/backup_helper_file.cpp b/libs/utils/backup_helper_file.cpp
index 1fa6a0f..bf56945 100644
--- a/libs/utils/backup_helper_file.cpp
+++ b/libs/utils/backup_helper_file.cpp
@@ -599,13 +599,14 @@
// hexdump -v -e '" " 8/1 " 0x%02x," "\n"' data_writer.data
const unsigned char DATA_GOLDEN_FILE[] = {
0x41, 0x70, 0x70, 0x31, 0x0b, 0x00, 0x00, 0x00,
- 0x6e, 0x6f, 0x5f, 0x70, 0x61, 0x64, 0x64, 0x69,
- 0x6e, 0x67, 0x5f, 0x00, 0x44, 0x61, 0x74, 0x61,
- 0x0b, 0x00, 0x00, 0x00, 0x0c, 0x00, 0x00, 0x00,
- 0x6e, 0x6f, 0x5f, 0x70, 0x61, 0x64, 0x64, 0x69,
- 0x6e, 0x67, 0x5f, 0x00, 0x6e, 0x6f, 0x5f, 0x70,
+ 0xdd, 0xcc, 0xbb, 0xaa, 0x6e, 0x6f, 0x5f, 0x70,
0x61, 0x64, 0x64, 0x69, 0x6e, 0x67, 0x5f, 0x00,
- 0x41, 0x70, 0x70, 0x31, 0x0c, 0x00, 0x00, 0x00,
+ 0x44, 0x61, 0x74, 0x61, 0x0b, 0x00, 0x00, 0x00,
+ 0x0c, 0x00, 0x00, 0x00, 0x6e, 0x6f, 0x5f, 0x70,
+ 0x61, 0x64, 0x64, 0x69, 0x6e, 0x67, 0x5f, 0x00,
+ 0x6e, 0x6f, 0x5f, 0x70, 0x61, 0x64, 0x64, 0x69,
+ 0x6e, 0x67, 0x5f, 0x00, 0x41, 0x70, 0x70, 0x31,
+ 0x0c, 0x00, 0x00, 0x00, 0xdd, 0xcc, 0xbb, 0xaa,
0x70, 0x61, 0x64, 0x64, 0x65, 0x64, 0x5f, 0x74,
0x6f, 0x5f, 0x5f, 0x33, 0x00, 0xbc, 0xbc, 0xbc,
0x44, 0x61, 0x74, 0x61, 0x0c, 0x00, 0x00, 0x00,
@@ -614,15 +615,16 @@
0x00, 0xbc, 0xbc, 0xbc, 0x70, 0x61, 0x64, 0x64,
0x65, 0x64, 0x5f, 0x74, 0x6f, 0x5f, 0x5f, 0x33,
0x00, 0xbc, 0xbc, 0xbc, 0x41, 0x70, 0x70, 0x31,
- 0x0d, 0x00, 0x00, 0x00, 0x70, 0x61, 0x64, 0x64,
+ 0x0d, 0x00, 0x00, 0x00, 0xdd, 0xcc, 0xbb, 0xaa,
+ 0x70, 0x61, 0x64, 0x64, 0x65, 0x64, 0x5f, 0x74,
+ 0x6f, 0x5f, 0x32, 0x5f, 0x5f, 0x00, 0xbc, 0xbc,
+ 0x44, 0x61, 0x74, 0x61, 0x0d, 0x00, 0x00, 0x00,
+ 0x0e, 0x00, 0x00, 0x00, 0x70, 0x61, 0x64, 0x64,
0x65, 0x64, 0x5f, 0x74, 0x6f, 0x5f, 0x32, 0x5f,
- 0x5f, 0x00, 0xbc, 0xbc, 0x44, 0x61, 0x74, 0x61,
- 0x0d, 0x00, 0x00, 0x00, 0x0e, 0x00, 0x00, 0x00,
- 0x70, 0x61, 0x64, 0x64, 0x65, 0x64, 0x5f, 0x74,
- 0x6f, 0x5f, 0x32, 0x5f, 0x5f, 0x00, 0xbc, 0xbc,
- 0x70, 0x61, 0x64, 0x64, 0x65, 0x64, 0x5f, 0x74,
- 0x6f, 0x5f, 0x32, 0x5f, 0x5f, 0x00, 0xbc, 0xbc,
- 0x41, 0x70, 0x70, 0x31, 0x0a, 0x00, 0x00, 0x00,
+ 0x5f, 0x00, 0xbc, 0xbc, 0x70, 0x61, 0x64, 0x64,
+ 0x65, 0x64, 0x5f, 0x74, 0x6f, 0x5f, 0x32, 0x5f,
+ 0x5f, 0x00, 0xbc, 0xbc, 0x41, 0x70, 0x70, 0x31,
+ 0x0a, 0x00, 0x00, 0x00, 0xdd, 0xcc, 0xbb, 0xaa,
0x70, 0x61, 0x64, 0x64, 0x65, 0x64, 0x5f, 0x74,
0x6f, 0x31, 0x00, 0xbc, 0x44, 0x61, 0x74, 0x61,
0x0a, 0x00, 0x00, 0x00, 0x0b, 0x00, 0x00, 0x00,
@@ -630,6 +632,7 @@
0x6f, 0x31, 0x00, 0xbc, 0x70, 0x61, 0x64, 0x64,
0x65, 0x64, 0x5f, 0x74, 0x6f, 0x31, 0x00, 0xbc,
0x46, 0x6f, 0x6f, 0x74, 0x04, 0x00, 0x00, 0x00,
+ 0x99, 0x99, 0x77, 0x77
};
const int DATA_GOLDEN_FILE_SIZE = sizeof(DATA_GOLDEN_FILE);
@@ -639,7 +642,7 @@
int err;
String8 text(str);
- err = writer.WriteAppHeader(text);
+ err = writer.WriteAppHeader(text, 0xaabbccdd);
if (err != 0) {
fprintf(stderr, "WriteAppHeader failed with %s\n", strerror(err));
return err;
@@ -685,7 +688,7 @@
err |= test_write_header_and_entity(writer, "padded_to_2__");
err |= test_write_header_and_entity(writer, "padded_to1");
- writer.WriteAppFooter();
+ writer.WriteAppFooter(0x77779999);
close(fd);
@@ -697,6 +700,162 @@
return err;
}
+int
+test_read_header_and_entity(BackupDataReader& reader, const char* str)
+{
+ int err;
+ int bufSize = strlen(str)+1;
+ char* buf = (char*)malloc(bufSize);
+ String8 string;
+ int cookie = 0x11111111;
+ size_t actualSize;
+
+ // printf("\n\n---------- test_read_header_and_entity -- %s\n\n", str);
+
+ err = reader.ReadNextHeader();
+ if (err != 0) {
+ fprintf(stderr, "ReadNextHeader (for app header) failed with %s\n", strerror(err));
+ goto done;
+ }
+
+ err = reader.ReadAppHeader(&string, &cookie);
+ if (err != 0) {
+ fprintf(stderr, "ReadAppHeader failed with %s\n", strerror(err));
+ goto done;
+ }
+ if (string != str) {
+ fprintf(stderr, "ReadAppHeader expected packageName '%s' got '%s'\n", str, string.string());
+ err = EINVAL;
+ goto done;
+ }
+ if (cookie != (int)0xaabbccdd) {
+ fprintf(stderr, "ReadAppHeader expected cookie 0x%08x got 0x%08x\n", 0xaabbccdd, cookie);
+ err = EINVAL;
+ goto done;
+ }
+
+ err = reader.ReadNextHeader();
+ if (err != 0) {
+ fprintf(stderr, "ReadNextHeader (for entity header) failed with %s\n", strerror(err));
+ goto done;
+ }
+
+ err = reader.ReadEntityHeader(&string, &actualSize);
+ if (err != 0) {
+ fprintf(stderr, "ReadEntityHeader failed with %s\n", strerror(err));
+ goto done;
+ }
+ if (string != str) {
+ fprintf(stderr, "ReadEntityHeader expected key '%s' got '%s'\n", str, string.string());
+ err = EINVAL;
+ goto done;
+ }
+ if ((int)actualSize != bufSize) {
+ fprintf(stderr, "ReadEntityHeader expected dataSize 0x%08x got 0x%08x\n", bufSize,
+ actualSize);
+ err = EINVAL;
+ goto done;
+ }
+
+ err = reader.ReadEntityData(buf, bufSize);
+ if (err != NO_ERROR) {
+ fprintf(stderr, "ReadEntityData failed with %s\n", strerror(err));
+ goto done;
+ }
+
+ if (0 != memcmp(buf, str, bufSize)) {
+ fprintf(stderr, "ReadEntityData expected '%s' but got something starting with "
+ "%02x %02x %02x %02x\n", str, buf[0], buf[1], buf[2], buf[3]);
+ err = EINVAL;
+ goto done;
+ }
+
+ // The next read will confirm whether it got the right amount of data.
+
+done:
+ if (err != NO_ERROR) {
+ fprintf(stderr, "test_read_header_and_entity failed with %s\n", strerror(err));
+ }
+ free(buf);
+ return err;
+}
+
+int
+backup_helper_test_data_reader()
+{
+ int err;
+ int fd;
+ const char* filename = SCRATCH_DIR "data_reader.data";
+
+ system("rm -r " SCRATCH_DIR);
+ mkdir(SCRATCH_DIR, 0777);
+ mkdir(SCRATCH_DIR "data", 0777);
+
+ fd = creat(filename, 0666);
+ if (fd == -1) {
+ fprintf(stderr, "error creating: %s\n", strerror(errno));
+ return errno;
+ }
+
+ err = write(fd, DATA_GOLDEN_FILE, DATA_GOLDEN_FILE_SIZE);
+ if (err != DATA_GOLDEN_FILE_SIZE) {
+ fprintf(stderr, "Error \"%s\" writing golden file %s\n", strerror(errno), filename);
+ return errno;
+ }
+
+ close(fd);
+
+ fd = open(filename, O_RDONLY);
+ if (fd == -1) {
+ fprintf(stderr, "Error \"%s\" opening golden file %s for read\n", strerror(errno),
+ filename);
+ return errno;
+ }
+
+ {
+ BackupDataReader reader(fd);
+
+ err = 0;
+
+ if (err == NO_ERROR) {
+ err = test_read_header_and_entity(reader, "no_padding_");
+ }
+
+ if (err == NO_ERROR) {
+ err = test_read_header_and_entity(reader, "padded_to__3");
+ }
+
+ if (err == NO_ERROR) {
+ err = test_read_header_and_entity(reader, "padded_to_2__");
+ }
+
+ if (err == NO_ERROR) {
+ err = test_read_header_and_entity(reader, "padded_to1");
+ }
+
+ if (err == NO_ERROR) {
+ err = reader.ReadNextHeader();
+ if (err != 0) {
+ fprintf(stderr, "ReadNextHeader (for app header) failed with %s\n", strerror(err));
+ }
+
+ if (err == NO_ERROR) {
+ int cookie;
+ err |= reader.ReadAppFooter(&cookie);
+ if (cookie != 0x77779999) {
+ fprintf(stderr, "app footer cookie expected=0x%08x actual=0x%08x\n",
+ 0x77779999, cookie);
+ err = EINVAL;
+ }
+ }
+ }
+ }
+
+ close(fd);
+
+ return err;
+}
+
static int
get_mod_time(const char* filename, struct timeval times[2])
{
diff --git a/tests/backup/backup_helper_test.cpp b/tests/backup/backup_helper_test.cpp
index 66240e3..1085909 100644
--- a/tests/backup/backup_helper_test.cpp
+++ b/tests/backup/backup_helper_test.cpp
@@ -23,6 +23,7 @@
{ "backup_helper_test_four", backup_helper_test_four, 0, false },
{ "backup_helper_test_files", backup_helper_test_files, 0, false },
{ "backup_helper_test_data_writer", backup_helper_test_data_writer, 0, false },
+ { "backup_helper_test_data_reader", backup_helper_test_data_reader, 0, false },
{ 0, NULL, 0, false}
};
