Thanks for the feedback, Justin. I've gone ahead and switched to use memcmp. I also refactored it to:
1. Don't assume that any file with first 4 bytes matching the relmapper magic number is a pg_relnode.map file
2. Don't assume the pg_relnode.map file is uncorrupted and intact; perform a check of the first 4 bytes against the reference magic number
3. Provide a flag (-m) for users to have their file interpreted as a pg_relnode.map file
I hope this is more palatable to everyone :)
--Richard
This is separate from the postgresql server repo.
https://git.postgresql.org/gitweb/?p=pg_filedump.git
+#define RELMAPPER_FILEMAGIC 0x592717
+char magic_buffer[8];
...
+ if ( (int) magic_buffer & RELMAPPER_FILEMAGIC ) {
This is doing bitwise arithmetic on a pointer, which seems badly wrong.
I think it breaks normal use of pg_filedump - unless you happen to get a
magic_buffer without those bits set. The segfault seems to confirm that, as
does gcc:
pg_filedump.c:2041:8: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
2041 | if ( (int) magic_buffer & RELMAPPER_FILEMAGIC ) {
I think it probably means to do memcmp, instead ??
--
Justin
