Re: [PATCH] Improved error messages when temporary file creation fails

Arnout Engelen [off-list ref] writes:

Thanks to you and Jonathan again for the feedback.

On Tue, Dec 07, 2010 at 12:56:17PM -0800, Junio C Hamano wrote:

quoted

quoted

+	char origtemplate[255];
+	strlcpy(origtemplate, template, 255);

Why "255"?

Random - 'i had to choose something'.

quoted

It may happen to be sufficiently large for the current callers, but what
provisions if any are made to help the compiler or the runtime protect us
from new and broken callers?  Use of strlcpy() there hides the issue from
the runtime by avoiding segfault, but it actively harms us by making the
code silently behave incorrectly without segfaulting, no?

Only in a small way: when a bigger template is encountered and the mkstemp 
call succeeds, there is no problem. Only when xmkstemp fails *and* clears the
template, the diagnostic error message shows a truncated version of the 
original.

Ah, ok, it seems that I misread the patch.  This copy you are making is
not used to actually construct the filename used for creating the
temporary file, so there is no risk the function misbehaving; we would
just give a truncated error report, which is no worse than what we have
been giving the users anyway.