Re: Forensic recovery deleted pgdump custom format file - Mailing list pgsql-hackers

This is the CloseArchive function at pg_backup_custom.c

WriteHead(AH);
tpos = ftello(AH->FH);
WriteToc(AH);
ctx->dataStart = _getFilePos(AH, ctx);
WriteDataChunks(AH);

This is the WriteHead function at pg_backup_archiver.c:(*AH->WriteBufPtr) (AH, "PGDMP", 5); /* Magic code */
(*AH->WriteBytePtr) (AH, AH->vmaj);
(*AH->WriteBytePtr) (AH, AH->vmin);
(*AH->WriteBytePtr) (AH, AH->vrev);
(*AH->WriteBytePtr) (AH, AH->intSize);
(*AH->WriteBytePtr) (AH, AH->offSize);
(*AH->WriteBytePtr) (AH, AH->format);
WriteInt(AH, AH->compression);
crtm = *localtime(&AH->createDate);
WriteInt(AH, crtm.tm_sec);
WriteInt(AH, crtm.tm_min);
WriteInt(AH, crtm.tm_hour);
WriteInt(AH, crtm.tm_mday);
WriteInt(AH, crtm.tm_mon);
WriteInt(AH, crtm.tm_year);
WriteInt(AH, crtm.tm_isdst);
WriteStr(AH, PQdb(AH->connection));
WriteStr(AH, AH->public.remoteVersionStr);
WriteStr(AH, PG_VERSION);

There is no mention to File Size or whatsoever in the Header..

void WriteToc(ArchiveHandle *AH) {

...

WriteInt(AH, tocCount);

but these structs are dynamic(linked list), so there is no way to know the size of each one...

At the definition of tocEntry struct, there is no reference to size or anything like that.. it is a linked list with a count number.

And at the end, the CloseArchive function calls WriteDataChunks to write blob information... i don't understand what this function is doing.. it save size information of blob data at the beginning? 

(*te->dataDumper) ((Archive *) AH, te->dataDumperArg);

What this function does?

David