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From: Bart Schaefer <schaefer@brasslantern.com>
Message-id: <150218084941.ZM21916@torch.brasslantern.com>
Date: Wed, 18 Feb 2015 08:49:41 -0800
In-reply-to: <20150218153012.GB18324@math.ethz.ch>
Comments: In reply to Theo Buehler <theo@math.ethz.ch>
 "Segfault because metafy() writes to a const char" (Feb 18,  4:30pm)
References: <20150218153012.GB18324@math.ethz.ch>
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To: <zsh-workers@zsh.org>
Subject: Re: Segfault because metafy() writes to a const char
Cc: Theo Buehler <theo@math.ethz.ch>, <pea@openbsd.org>
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On Feb 18,  4:30pm, Theo Buehler wrote:
} Subject: Segfault because metafy() writes to a const char
}
} The following patch fixes this problem for me, however, it effectively
} undoes a patch discussed in this thread:
} 
} 
} http://www.zsh.org/mla/workers/2013/msg01089.html
} 
} and, especially here:
} 
} http://www.zsh.org/mla/workers/2013/msg01091.html

If you look at the followup to that message:

http://www.zsh.org/mla/workers/2013/msg01092.html

("we need to change the caller")  The fix should be this:


diff --git a/Src/module.c b/Src/module.c
index 7dd4701..368254c 100644
--- a/Src/module.c
+++ b/Src/module.c
@@ -1601,7 +1601,7 @@ do_load_module(char const *name, int silent)
 #ifdef HAVE_DLERROR
 	char *errstr = dlerror();
 	zwarn("failed to load module `%s': %s", name,
-	      errstr ? metafy(errstr, -1, META_USEHEAP) : "empty module path");
+	      errstr ? metafy(errstr, -1, META_HEAPDUP) : "empty module path");
 #else
 	zwarn("failed to load module: %s", name);
 #endif

(Could probably even use META_STATIC there, the dlerror string is not very
likely to be too long for PATH_MAX.)

It still seems as though we should be able to avoid nul-terminating a
string that's already nul-terminated without changing the call sign of
metafy().