*
* Backup data is stored in a collection of objects, which are grouped together
* into segments for storage purposes. This implementation of the object store
- * is built on top of libtar, and represents segments as TAR files and objects
- * as files within them. */
+ * represents segments as TAR files and objects as files within them. */
#ifndef _LBS_STORE_H
#define _LBS_STORE_H
#include <stdint.h>
-#include <libtar.h>
#include <list>
#include <map>
#include <iostream>
#include <sstream>
+#include "localdb.h"
#include "sha1.h"
#include "ref.h"
std::string getError() const { return error; }
};
+/* Simplified TAR header--we only need to store regular files, don't need to
+ * handle long filenames, etc. */
+static const int TAR_BLOCK_SIZE = 512;
+
+struct tar_header
+{
+ char name[100];
+ char mode[8];
+ char uid[8];
+ char gid[8];
+ char size[12];
+ char mtime[12];
+ char chksum[8];
+ char typeflag;
+ char linkname[100];
+ char magic[8];
+ char uname[32];
+ char gname[32];
+ char devmajor[8];
+ char devminor[8];
+ char prefix[155];
+ char padding[12];
+};
+
/* A simple wrapper around a single TAR file to represent a segment. Objects
* may only be written out all at once, since the tar header must be written
* first; incremental writing is not supported. */
Tarfile(const std::string &path, const std::string &segment);
~Tarfile();
- int spawn_filter(int fd_out);
void write_object(int id, const char *data, size_t len);
// Return an estimate of the size of the file.
size_t size_estimate();
- void internal_write_object(const std::string &path,
- const char *data, size_t len);
-
private:
size_t size;
std::string segment_name;
- TAR *t;
/* Filter support. */
int real_fd, filter_fd;
pid_t filter_pid;
+
+ // Write data to the tar file
+ void tar_write(const char *data, size_t size);
};
class TarSegmentStore {
public:
// New segments will be stored in the given directory.
- TarSegmentStore(const std::string &path) { this->path = path; }
+ TarSegmentStore(const std::string &path,
+ LocalDb *db = NULL)
+ { this->path = path; this->db = db; }
~TarSegmentStore() { sync(); }
// Writes an object to segment in the store, and returns the name
// Ensure all segments have been fully written.
void sync();
+ // Dump statistics to stdout about how much data has been written
+ void dump_stats();
+
private:
struct segment_info {
Tarfile *file;
std::string name; // UUID
int count; // Objects written to this segment
+ int size; // Combined size of objects written
+ std::string basename; // Name of segment without directory
+ std::string fullname; // Full path to stored segment
};
std::string path;
std::map<std::string, struct segment_info *> segments;
+ LocalDb *db;
// Ensure that all segments in the given group have been fully written.
void close_segment(const std::string &group);
ObjectReference ref;
};
+/* Program through which segment data is piped before being written to file. */
+extern const char *filter_program;
+
+/* Extension which should be appended to segments written out (.tar is already
+ * included; this adds to it) */
+extern const char *filter_extension;
+
+/* Launch a process to filter data written to a file descriptor. fd_out is the
+ * file descriptor where the filtered data should be written. program is the
+ * filter program to execute (a single string which will be interpreted by
+ * /bin/sh). The return value is a file descriptor to which the data to be
+ * filtered should be written. The process ID of the filter process is stored
+ * at address filter_pid if non-NULL. */
+int spawn_filter(int fd_out, const char *program, pid_t *filter_pid);
+
#endif // _LBS_STORE_H