[SOLVED] Unable to Build Newlib

R0b0t1 · Apprentice Joined: 05 Jun 2008 Posts: 264

Like the issue with GCC, this is a source error, so I have tried asking on the newlib mailing list. Unfortunately no response yet.

Hu · Moderator Joined: 06 Mar 2007 Posts: 21595

gets() was a horrible mistake. It was only removed from the language in C11, but it has never been correct. Personally, I think you should resolve this by removing the definition of gets() entirely. Any breakage that results is a good thing. It will warn you of the existence of programs that try to use this function.

Setting aside how you should never facilitate anyone using this, I concur with your assessment. Your build environment likely made a macro gets() that tries to perform some sanity checks. Could you post the post-processed output of that file, so that we can see how the macro was expanded?

R0b0t1 · Apprentice Joined: 05 Jun 2008 Posts: 264

Thanks Hu, that seemed like something reasonable enough to try, unfortunately:

Mr. T. · Guru Joined: 26 Dec 2016 Posts: 477

Mr. T. · Guru Joined: 26 Dec 2016 Posts: 477

R0b0t1, you should provide the needed files to fix errors.

Edition: Sorry, I did not think enough: the source code may be found on the mentioned GitHub.

Hu · Moderator Joined: 06 Mar 2007 Posts: 21595

It looks like all the stdio functions that can be hardened by _FORTIFY_SOURCE are choking here. This suggests that the build environment has enabled source fortification when it should not. Source fortification is to be used when compiling the programs that call stdio, not when compiling stdio itself.

helecho, yes, I am aware of the source, but since his output clearly disagrees with a direct parsing of the source, I believe macro expansion to be a key part of this. Yes, gcc's object size check intrinsics are invoked by the post-processed code, but that doesn't mean gcc is at fault for the failure. (Although, a hardened-by-default gcc might be enabling _FORTIFY_SOURCE, which if not expected by the newlib build system, could cause a failure like this.)

R0b0t1 · Apprentice Joined: 05 Jun 2008 Posts: 264

Hu · Moderator Joined: 06 Mar 2007 Posts: 21595

That post-processed text looks consistent with having a macro such as

R0b0t1 · Apprentice Joined: 05 Jun 2008 Posts: 264

I agree. For the time being I have set _FORTIFY_SOURCE=1. This must be done in the target's newlib directory containing the Makefile, if you need to do it by hand. The configuration script does not seem to accept CFLAGS and pass it to the produced Makefiles.