Segfault when displaying completion lists

Segfault when displaying completion lists

[Christian Heinrich]

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Hello,

I'm running ZSH 5.2-3 on my Debian Testing system. This error existed
previously, too, but I only found the time today to find a minimal
setup for this. Here we go:

% zsh --norcs
% zmodload zsh/complist
% autoload -U compinit && compinit -d ~/.zsh/cache/zcompdump 
% zstyle ':completion:*' list-prompt '%p'
% bindkey -d
% ls /usr/lib/<TAB>
Now a huge list should be displayed with a pager. Press "Arrow Down"
and it should segfault.


This does not happen if the "zsh/complist" module is not loaded.

Another interesting observation:

After the <TAB>, press backspace instead of "arrow down" and remove the
whole command (do not accept the line). Type "bindkey -d" (yes, a 2nd
time) and accept. Type "ls /usr/lib/<TAB>" again and press backspace.
It segfaults now, although backspacing worked the first time.

Maybe someone can find the reason for this? I do have EDITOR="vim" set,
but it appears as if it happens with EDITOR="emacs" as well.


Thanks!

Christian

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Re: Segfault when displaying completion lists

[Eric Cook]

On 02/08/2016 05:58 PM, Christian Heinrich wrote:
> Hello,
> 
> I'm running ZSH 5.2-3 on my Debian Testing system. This error existed
> previously, too, but I only found the time today to find a minimal
> setup for this. Here we go:
> 
> % zsh --norcs
> % zmodload zsh/complist
> % autoload -U compinit && compinit -d ~/.zsh/cache/zcompdump 
> % zstyle ':completion:*' list-prompt '%p'
> % bindkey -d
> % ls /usr/lib/<TAB>
> Now a huge list should be displayed with a pager. Press "Arrow Down"
> and it should segfault.
> 
> 
> This does not happen if the "zsh/complist" module is not loaded.
> 
> Another interesting observation:
> 
> After the <TAB>, press backspace instead of "arrow down" and remove the
> whole command (do not accept the line). Type "bindkey -d" (yes, a 2nd
> time) and accept. Type "ls /usr/lib/<TAB>" again and press backspace.
> It segfaults now, although backspacing worked the first time.
> 
> Maybe someone can find the reason for this? I do have EDITOR="vim" set,
> but it appears as if it happens with EDITOR="emacs" as well.
> 
> 
> Thanks!
> 
> Christian
> 

This is a guess:

menu selection requires a keymap named menuselect to function. you can view
it with ''bindkey -l''. This keymap is provided by the complist module
that you loaded initially, then sequentially deleted with ''bindkey -d''
returning the keymaps back to a default state.

The zsh/complist is loaded automatically on first use of menuselect,
which explains why ''zmodload zsh/complist'' is required for the segfault.

If my guess is true, zsh should handle the menuselect keymap not existing more elegantly.
But i wouldn't expect menuselect to be of much use without keybinds.

Re: Segfault when displaying completion lists

[Bart Schaefer]

On Feb 8,  6:39pm, Eric Cook wrote:
}
} This is a guess:

Pretty good one.

} If my guess is true, zsh should handle the menuselect keymap not
} existing more elegantly.

This is a bit brute-force, but perhaps the following?  It has the added
side-effect that if you create your own keymap named "menuselect" and/or
"listscroll" before loading zsh/complist, your bindings take precedence.

diff --git a/Src/Zle/complist.c b/Src/Zle/complist.c
index 06a07a4..937e1d1 100644
--- a/Src/Zle/complist.c
+++ b/Src/Zle/complist.c
@@ -989,6 +989,7 @@ asklistscroll(int ml)
 
     fflush(shout);
     zsetterm();
+    menuselect_bindings();	/* sanity in case deleted by user */
     selectlocalmap(lskeymap);
     if (!(cmd = getkeycmd()) || cmd == Th(z_sendbreak))
 	ret = 1;
@@ -2433,6 +2434,7 @@ domenuselect(Hookdef dummy, Chdata dat)
     unqueue_signals();
     mhasstat = (mstatus && *mstatus);
     fdat = dat;
+    menuselect_bindings();	/* sanity in case deleted by user */
     selectlocalmap(mskeymap);
     noselect = 1;
     while ((menuacc &&
@@ -3486,6 +3488,37 @@ enables_(Module m, int **enables)
 }
 
 /**/
+static void
+menuselect_bindings(void)
+{
+    if (!(mskeymap = openkeymap("menuselect"))) {
+	mskeymap = newkeymap(NULL, "menuselect");
+	linkkeymap(mskeymap, "menuselect", 1);
+	bindkey(mskeymap, "\t", refthingy(t_completeword), NULL);
+	bindkey(mskeymap, "\n", refthingy(t_acceptline), NULL);
+	bindkey(mskeymap, "\r", refthingy(t_acceptline), NULL);
+	bindkey(mskeymap, "\33[A",  refthingy(t_uplineorhistory), NULL);
+	bindkey(mskeymap, "\33[B",  refthingy(t_downlineorhistory), NULL);
+	bindkey(mskeymap, "\33[C",  refthingy(t_forwardchar), NULL);
+	bindkey(mskeymap, "\33[D",  refthingy(t_backwardchar), NULL);
+	bindkey(mskeymap, "\33OA",  refthingy(t_uplineorhistory), NULL);
+	bindkey(mskeymap, "\33OB",  refthingy(t_downlineorhistory), NULL);
+	bindkey(mskeymap, "\33OC",  refthingy(t_forwardchar), NULL);
+	bindkey(mskeymap, "\33OD",  refthingy(t_backwardchar), NULL);
+    }
+    if (!(lskeymap = openkeymap("listscroll"))) {
+	lskeymap = newkeymap(NULL, "listscroll");
+	linkkeymap(lskeymap, "listscroll", 1);
+	bindkey(lskeymap, "\t", refthingy(t_completeword), NULL);
+	bindkey(lskeymap, " ", refthingy(t_completeword), NULL);
+	bindkey(lskeymap, "\n", refthingy(t_acceptline), NULL);
+	bindkey(lskeymap, "\r", refthingy(t_acceptline), NULL);
+	bindkey(lskeymap, "\33[B",  refthingy(t_downlineorhistory), NULL);
+	bindkey(lskeymap, "\33OB",  refthingy(t_downlineorhistory), NULL);
+    }
+}
+
+/**/
 int
 boot_(Module m)
 {
@@ -3503,27 +3536,7 @@ boot_(Module m)
     }
     addhookfunc("comp_list_matches", (Hookfn) complistmatches);
     addhookfunc("menu_start", (Hookfn) domenuselect);
-    mskeymap = newkeymap(NULL, "menuselect");
-    linkkeymap(mskeymap, "menuselect", 1);
-    bindkey(mskeymap, "\t", refthingy(t_completeword), NULL);
-    bindkey(mskeymap, "\n", refthingy(t_acceptline), NULL);
-    bindkey(mskeymap, "\r", refthingy(t_acceptline), NULL);
-    bindkey(mskeymap, "\33[A",  refthingy(t_uplineorhistory), NULL);
-    bindkey(mskeymap, "\33[B",  refthingy(t_downlineorhistory), NULL);
-    bindkey(mskeymap, "\33[C",  refthingy(t_forwardchar), NULL);
-    bindkey(mskeymap, "\33[D",  refthingy(t_backwardchar), NULL);
-    bindkey(mskeymap, "\33OA",  refthingy(t_uplineorhistory), NULL);
-    bindkey(mskeymap, "\33OB",  refthingy(t_downlineorhistory), NULL);
-    bindkey(mskeymap, "\33OC",  refthingy(t_forwardchar), NULL);
-    bindkey(mskeymap, "\33OD",  refthingy(t_backwardchar), NULL);
-    lskeymap = newkeymap(NULL, "listscroll");
-    linkkeymap(lskeymap, "listscroll", 1);
-    bindkey(lskeymap, "\t", refthingy(t_completeword), NULL);
-    bindkey(lskeymap, " ", refthingy(t_completeword), NULL);
-    bindkey(lskeymap, "\n", refthingy(t_acceptline), NULL);
-    bindkey(lskeymap, "\r", refthingy(t_acceptline), NULL);
-    bindkey(lskeymap, "\33[B",  refthingy(t_downlineorhistory), NULL);
-    bindkey(lskeymap, "\33OB",  refthingy(t_downlineorhistory), NULL);
+    menuselect_bindings();
     return 0;
 }
 

Re: Segfault when displaying completion lists

[Christian Heinrich]

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Thanks guys, that was exactly the issue. I recompiled the code and it
works just as it should!

Christian

On Mon, 2016-02-08 at 22:00 -0800, Bart Schaefer wrote:
> On Feb 8,  6:39pm, Eric Cook wrote:
> }
> } This is a guess:
> 
> Pretty good one.
> 
> } If my guess is true, zsh should handle the menuselect keymap not
> } existing more elegantly.
> 
> This is a bit brute-force, but perhaps the following?  It has the
> added
> side-effect that if you create your own keymap named "menuselect"
> and/or
> "listscroll" before loading zsh/complist, your bindings take
> precedence.
> 
> diff --git a/Src/Zle/complist.c b/Src/Zle/complist.c
> index 06a07a4..937e1d1 100644
> --- a/Src/Zle/complist.c
> +++ b/Src/Zle/complist.c
> @@ -989,6 +989,7 @@ asklistscroll(int ml)
>  
>      fflush(shout);
>      zsetterm();
> +    menuselect_bindings();	/* sanity in case deleted by user
> */
>      selectlocalmap(lskeymap);
>      if (!(cmd = getkeycmd()) || cmd == Th(z_sendbreak))
>  	ret = 1;
> @@ -2433,6 +2434,7 @@ domenuselect(Hookdef dummy, Chdata dat)
>      unqueue_signals();
>      mhasstat = (mstatus && *mstatus);
>      fdat = dat;
> +    menuselect_bindings();	/* sanity in case deleted by user
> */
>      selectlocalmap(mskeymap);
>      noselect = 1;
>      while ((menuacc &&
> @@ -3486,6 +3488,37 @@ enables_(Module m, int **enables)
>  }
>  
>  /**/
> +static void
> +menuselect_bindings(void)
> +{
> +    if (!(mskeymap = openkeymap("menuselect"))) {
> +	mskeymap = newkeymap(NULL, "menuselect");
> +	linkkeymap(mskeymap, "menuselect", 1);
> +	bindkey(mskeymap, "\t", refthingy(t_completeword), NULL);
> +	bindkey(mskeymap, "\n", refthingy(t_acceptline), NULL);
> +	bindkey(mskeymap, "\r", refthingy(t_acceptline), NULL);
> +	bindkey(mskeymap, "\33[A",  refthingy(t_uplineorhistory),
> NULL);
> +	bindkey(mskeymap, "\33[B",  refthingy(t_downlineorhistory),
> NULL);
> +	bindkey(mskeymap, "\33[C",  refthingy(t_forwardchar), NULL);
> +	bindkey(mskeymap, "\33[D",  refthingy(t_backwardchar),
> NULL);
> +	bindkey(mskeymap, "\33OA",  refthingy(t_uplineorhistory),
> NULL);
> +	bindkey(mskeymap, "\33OB",  refthingy(t_downlineorhistory),
> NULL);
> +	bindkey(mskeymap, "\33OC",  refthingy(t_forwardchar), NULL);
> +	bindkey(mskeymap, "\33OD",  refthingy(t_backwardchar),
> NULL);
> +    }
> +    if (!(lskeymap = openkeymap("listscroll"))) {
> +	lskeymap = newkeymap(NULL, "listscroll");
> +	linkkeymap(lskeymap, "listscroll", 1);
> +	bindkey(lskeymap, "\t", refthingy(t_completeword), NULL);
> +	bindkey(lskeymap, " ", refthingy(t_completeword), NULL);
> +	bindkey(lskeymap, "\n", refthingy(t_acceptline), NULL);
> +	bindkey(lskeymap, "\r", refthingy(t_acceptline), NULL);
> +	bindkey(lskeymap, "\33[B",  refthingy(t_downlineorhistory),
> NULL);
> +	bindkey(lskeymap, "\33OB",  refthingy(t_downlineorhistory),
> NULL);
> +    }
> +}
> +
> +/**/
>  int
>  boot_(Module m)
>  {
> @@ -3503,27 +3536,7 @@ boot_(Module m)
>      }
>      addhookfunc("comp_list_matches", (Hookfn) complistmatches);
>      addhookfunc("menu_start", (Hookfn) domenuselect);
> -    mskeymap = newkeymap(NULL, "menuselect");
> -    linkkeymap(mskeymap, "menuselect", 1);
> -    bindkey(mskeymap, "\t", refthingy(t_completeword), NULL);
> -    bindkey(mskeymap, "\n", refthingy(t_acceptline), NULL);
> -    bindkey(mskeymap, "\r", refthingy(t_acceptline), NULL);
> -    bindkey(mskeymap, "\33[A",  refthingy(t_uplineorhistory), NULL);
> -    bindkey(mskeymap, "\33[B",  refthingy(t_downlineorhistory),
> NULL);
> -    bindkey(mskeymap, "\33[C",  refthingy(t_forwardchar), NULL);
> -    bindkey(mskeymap, "\33[D",  refthingy(t_backwardchar), NULL);
> -    bindkey(mskeymap, "\33OA",  refthingy(t_uplineorhistory), NULL);
> -    bindkey(mskeymap, "\33OB",  refthingy(t_downlineorhistory),
> NULL);
> -    bindkey(mskeymap, "\33OC",  refthingy(t_forwardchar), NULL);
> -    bindkey(mskeymap, "\33OD",  refthingy(t_backwardchar), NULL);
> -    lskeymap = newkeymap(NULL, "listscroll");
> -    linkkeymap(lskeymap, "listscroll", 1);
> -    bindkey(lskeymap, "\t", refthingy(t_completeword), NULL);
> -    bindkey(lskeymap, " ", refthingy(t_completeword), NULL);
> -    bindkey(lskeymap, "\n", refthingy(t_acceptline), NULL);
> -    bindkey(lskeymap, "\r", refthingy(t_acceptline), NULL);
> -    bindkey(lskeymap, "\33[B",  refthingy(t_downlineorhistory),
> NULL);
> -    bindkey(lskeymap, "\33OB",  refthingy(t_downlineorhistory),
> NULL);
> +    menuselect_bindings();
>      return 0;
>  }
>  

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