windows - How can you change an age-mismatched PDB to match properly?

Question

Our nightly build process was broken for a long time, such that it generated PDB files that were a few hours different in age than the corresponding image files. I have since fixed the problem.

However, I would like to start using a symbol server, but cannot due to having to use these age-mismatched pdb files. I work around this issue by using the .symopt +0x40 method in windbg. That means I have to organize all my pdb files by hand, and after years upon years of releases, that adds up.

I am looking for a way to modify the mechanism that windbg uses to mark a pdb's age, and force it to match my image file. The utility ChkMatch does something similar, but for pdb signatures. The developer states on the page "ChkMatch is capable of making an executable and PDB file match if they have different signatures but the same age (see this article for more information about PDB signature and age). If the age differs, the tool cannot make the files match."

I took a look inside a hexeditor, and even found what looked like the bits corresponding to the age, but it must pull some more tricks internally, cause I couldn't get it to work.

Any ideas?

EDIT: I don't know if this helps, but in my particular case the age difference was caused by unnecessarily relinking dll's, which would recreate the PDB files as well. However, our build process was storing the original dlls (before the relink), and the pdb after the relink. I thought about somehow recreating such a situation by hand. Meaning, forcing a relink on a DLL, but saving off the pdb in both cases. Then I could do a binary compare of the two files to see how they changed. Perhaps run some sort of patching software that does this automatically? By seeing what exactly changed in my control case, perhaps I could do the same to the DLLs and PDBs saved in my companies build process?

EDIT: I FIGURED IT OUT!!!! Thanks to one of the comments on the first answer, I checked out a link to the pdfs of the book "Undocumented Windows 2000 Secrets: A Programmers Cookbook". And the author goes into great detail about the pdb file format. As I said before, I had already loaded the pdb into a hex editor and flipped some bits around appearing that I made the age/signature match, but it didn't work. Well, after using the utility from the W2k secrets book to "explode" the pdb into the included streams, I found out that they hide another reference to the age in stream 3!!!!!!! Once I flipped that one as well, it matched up in windbg. THIS IS HUGE!!!! Thank you so much....symbol server HERE I COME!

Answer 1

the windbg will not modify pdb's age - it only looks it up to match that of executable - the compiler does when it (re)generates executable and debug files.

now, based on the debuginfo.com article, it is not too difficult to arrive at the proper debug directory (of type codeview), match it against PDB7 signature and make modifications to either age or GUID inside an executable. why is that not an option?

i guess, you want to update pdb instead? i'm afraid, pdb is a proprietary format. there're multiple read-only APIs (dbghelp.dll and dia sdk), but as far as modifications go, you need to guess the details to be able to modify.