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From: Kamil Dudka <kdudka@redhat.com>
To: Peter Stephenson <p.stephenson@samsung.com>
Cc: zsh-workers@zsh.org
Subject: Re: infinite recursion in ihungetc()
Date: Wed, 22 Jul 2015 16:00:10 +0200
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On Wednesday 22 July 2015 14:38:03 Peter Stephenson wrote:
> Yes, it should be straightforward to prevent, although this code isn't
> particularly transparent (or new), so I don't know how you could get
> there.
> 
> pws

I do not know it either because these crash reports are anonymous.  I will 
just apply your patch to fix it and let you know if we get any feedback.  
Thanks for the patch!

Kamil

> diff --git a/Src/hist.c b/Src/hist.c
> index 6725313..cf224cb 100644
> --- a/Src/hist.c
> +++ b/Src/hist.c
> @@ -136,6 +136,7 @@ mod_export int hist_skip_flags;
>  #define HA_NOINC	(1<<1)	/* Don't store, curhist not incremented */
>  #define HA_INWORD       (1<<2)  /* We're inside a word, don't add
>  				   start and end markers */
> +#define HA_UNGET        (1<<3)  /* Recursively ungetting */
> 
>  /* Array of word beginnings and endings in current history line. */
> 
> @@ -904,8 +905,13 @@ ihungetc(int c)
> 
>      while (!lexstop && !errflag) {
>  	if (hptr[-1] != (char) c && stophist < 4 &&
> -	    hptr > chline + 1 && hptr[-1] == '\n' && hptr[-2] == '\\')
> -	    hungetc('\n'), hungetc('\\');
> +	    hptr > chline + 1 && hptr[-1] == '\n' && hptr[-2] == '\\' &&
> +	    !(histactive & HA_UNGET)) {
> +	    histactive |= HA_UNGET;
> +	    hungetc('\n');
> +	    hungetc('\\');
> +	    histactive &= ~HA_UNGET;
> +	}
> 
>  	if (expanding) {
>  	    zlemetacs--;