Date: Sat, 9 Feb 2008 22:20:02 GMT From: Yar Tikhiy <yar@comp.chem.msu.su> To: freebsd-bugs@FreeBSD.org Subject: Re: bin/21089: vi silently corrupt open file on SIGINT when entering :wq in command mode Message-ID: <200802092220.m19MK28g036458@freefall.freebsd.org>
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The following reply was made to PR bin/21089; it has been noted by GNATS. From: Yar Tikhiy <yar@comp.chem.msu.su> To: Jaakko Heinonen <jh@saunalahti.fi> Cc: bug-followup@freebsd.org Subject: Re: bin/21089: vi silently corrupt open file on SIGINT when entering :wq in command mode Date: Sun, 10 Feb 2008 01:12:44 +0300 Jaakko, I think that you looked in the right direction but applied the fix at a wrong level. In fact, we shouldn't put a test for INTERRUPTED(sp) into each ex command's implementation. In ex mode, the call stack is as follows: main -> editor -> ex -> ex_cmd -> <individual command> Among the functions, it's ex() that takes care of INTERRUPTED(sp). Therefore we should do something similar, too, when ex_cmd() is called from vi mode. In the latter case the call stack looks as follows: main -> editor -> vi -> v_ex -> ex_cmd -> <individual command> So we should be looking at somewhere around v_ex(). But, in fact, a similar problem is found in all consumers of v_tcmd(): ^C doesn't abort the command being typed, it commits the command instead. That applies both to colon commands and to search commands. In the case of `:w' the problem just gets much worse because interrupted status remains set and blows up the command later. To make things even more complicated, a window resize event behaves much like ^C in that it commits the command being typed, which can have an unwanted result. The NetBSD folks seem to have fixed this bug generally in v_ex.c and v_text.c, but their fix is hackish, too: they now pretend that ^C or a window resize event is the same as <Esc>. What perhaps is needed is a clear indication from v_txt() to its caller that a special event ended text input, so that it can be up to the caller to decide how to handle the event. But for now the ^C bug can be fixed quickly as shown in the attached patch. With the patch applied, ^C will commit neither ex commands nor search commands: it'll abort them instead, which makes much more sense IMHO. Yar Index: vi/v_txt.c =================================================================== RCS file: /home/ncvs/src/contrib/nvi/vi/v_txt.c,v retrieving revision 1.1.1.1 diff -u -p -r1.1.1.1 v_txt.c --- vi/v_txt.c 1 Nov 1996 06:45:33 -0000 1.1.1.1 +++ vi/v_txt.c 9 Feb 2008 22:06:02 -0000 @@ -110,6 +110,10 @@ v_tcmd(sp, vp, prompt, flags) sp->lno = vp->m_final.lno; sp->cno = vp->m_final.cno; + /* Interrupt aborts the command. */ + if (INTERRUPTED(sp)) + return (1); + return (0); }
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