[PATCH v4 0/2] TIOCLINUX.2const: Document TIOCL_SETSEL selection modes

[PATCH v4 0/2] TIOCLINUX.2const: Document TIOCL_SETSEL selection modes

[Günther Noack]

Hi!

TIOCLINUX's TIOCL_SETSEL sub-code has another layer of sub-operations,
called "selection modes" (even though not all of them actually deal
with the mouse selection).

Going forward, the CAP_SYS_ADMIN requirement will be different for
some of these selection modes, which prompted me to at least list the
different selection modes with a short description.  I am leaving
CAP_SYS_ADMIN documentation as it is for now and will send another
patch once these semantics are finalized [1] [2].

Thanks,
–Günther

[1] <https://lore.kernel.org/all/20250221.0a947528d8f3@gnoack.org/>
[2] <https://lore.kernel.org/all/20250223205449.7432-2-gnoack3000@gmail.com/>

History:

V2:
 * Split into a "restructuring" and a "new documentation" commit
 * Use non-breaking space \~
 * Put URIs in <>
 * Added a helpful link to console_codes(4) regarding mouse reporting

V3:
 * Corrections and clarifications for various selection modes
   as suggested by Jared Finder. (Thanks!)

V4:
 * Clarified how TIOCL_SELPOINTER selects the coordinate to use

Günther Noack (2):
  TIOCLINUX.2const: Restructure documentation for TIOCL_SETSEL selection
    modes
  TIOCLINUX.2const: Document missing TIOCL_SETSEL selection modes

 man/man2const/TIOCLINUX.2const | 59 +++++++++++++++++++++++++++++++---
 1 file changed, 54 insertions(+), 5 deletions(-)

Range-diff against v3:
1:  d07edb528 = 1:  828c5189a TIOCLINUX.2const: Restructure documentation for TIOCL_SETSEL selection modes
2:  59f217fb0 ! 2:  bffc3e550 TIOCLINUX.2const: Document missing TIOCL_SETSEL selection modes
    @@ man/man2const/TIOCLINUX.2const: Select line-by-line,
     +.RI ( xs ,\~ ys )
     +or
     +.RI ( xe ,\~ ye ),
    -+whichever is greater.
    ++whichever is later in text flow order.
     +.TP
     +.B TIOCL_SELCLEAR
     +Remove the current selection highlight, if any,
-- 
2.49.0

[PATCH v4 1/2] TIOCLINUX.2const: Restructure documentation for TIOCL_SETSEL selection modes

[Günther Noack]

* Indent the documented selection modes into tagged paragraphs.
* Document constants from the header file (tiocl.h) instead of numbers.
* Clarify expansion semantics as suggested by Jared Finder.

Signed-off-by: Günther Noack <gnoack3000@gmail.com>
---
 man/man2const/TIOCLINUX.2const | 25 ++++++++++++++++++++-----
 1 file changed, 20 insertions(+), 5 deletions(-)

diff --git a/man/man2const/TIOCLINUX.2const b/man/man2const/TIOCLINUX.2const
index c0acdd0ea..f2c8d0720 100644
--- a/man/man2const/TIOCLINUX.2const
+++ b/man/man2const/TIOCLINUX.2const
@@ -65,11 +65,26 @@ are the ending
 column and row.
 (Upper left corner is row=column=1.)
 .I sel_mode
-is 0 for character-by-character selection,
-1 for word-by-word selection,
-or 2 for line-by-line selection.
-The indicated screen characters are highlighted and saved
-in a kernel buffer.
+may be one of the following operations:
+.RS
+.TP
+.B TIOCL_SELCHAR
+Select character-by-character.
+The indicated screen characters are highlighted
+and saved in a kernel buffer.
+.TP
+.B TIOCL_SELWORD
+Select word-by-word,
+expanding the selection outwards to align with word boundaries.
+The indicated screen characters are highlighted
+and saved in a kernel buffer.
+.TP
+.B TIOCL_SELLINE
+Select line-by-line,
+expanding the selection outwards to select full lines.
+The indicated screen characters are highlighted
+and saved in a kernel buffer.
+.RE
 .IP
 Since Linux 6.7, using this subcode requires the
 .B CAP_SYS_ADMIN
-- 
2.49.0

[PATCH v4 2/2] TIOCLINUX.2const: Document missing TIOCL_SETSEL selection modes

[Günther Noack]

Documents the following TIOCL_SETSEL sub-operations:

* TIOCL_SELPOINTER
* TIOCL_SELCLEAR
* TIOCL_SELMOUSEREPORT

These previously undocumented selection modes for the Linux console
are implemented in drivers/tty/vt/selection.c.  The name "selection
mode" is slightly misleading as not all of them actually manipulate
the kernel's mouse selection buffer.

Includes clarified semantics pointed out by Jared Finder.

Cc: Jared Finder <jared@finder.org>
Cc: Hanno Böck <hanno@hboeck.de>
Cc: Jann Horn <jannh@google.com>
Cc: Jiri Slaby <jirislaby@kernel.org>
Cc: jwilk@jwilk.net
Signed-off-by: Günther Noack <gnoack3000@gmail.com>
---
 man/man2const/TIOCLINUX.2const | 34 ++++++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/man/man2const/TIOCLINUX.2const b/man/man2const/TIOCLINUX.2const
index f2c8d0720..61f1c596d 100644
--- a/man/man2const/TIOCLINUX.2const
+++ b/man/man2const/TIOCLINUX.2const
@@ -84,6 +84,40 @@ Select line-by-line,
 expanding the selection outwards to select full lines.
 The indicated screen characters are highlighted
 and saved in a kernel buffer.
+.TP
+.B TIOCL_SELPOINTER
+Show the pointer at position
+.RI ( xs ,\~ ys )
+or
+.RI ( xe ,\~ ye ),
+whichever is later in text flow order.
+.TP
+.B TIOCL_SELCLEAR
+Remove the current selection highlight, if any,
+from the console holding the selection.
+.IP
+This does not affect the stored selected text.
+.TP
+.B TIOCL_SELMOUSEREPORT
+Make the terminal report
+.RI ( xs ,\~ ys )
+as the current mouse location
+using the
+.BR xterm (1)
+mouse tracking protocol
+(see
+.BR console_codes (4)).
+The lower 4 bits of
+.I sel_mode
+.RB ( TIOCL_SELBUTTONMASK )
+indicate the desired button press and
+modifier key information for the mouse event.
+.\" <https://invisible-island.net/xterm/ctlseqs/ctlseqs.html#h3-Normal-tracking-mode>
+.IP
+If mouse reporting is not enabled for the terminal,
+this operation yields an
+.B EINVAL
+error.
 .RE
 .IP
 Since Linux 6.7, using this subcode requires the
-- 
2.49.0

Re: [PATCH v4 0/2] TIOCLINUX.2const: Document TIOCL_SETSEL selection modes

[Alejandro Colomar]

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Hi Günther, Jared,

On Sun, Mar 30, 2025 at 04:30:37PM +0200, Günther Noack wrote:
> Hi!
> 
> TIOCLINUX's TIOCL_SETSEL sub-code has another layer of sub-operations,
> called "selection modes" (even though not all of them actually deal
> with the mouse selection).
> 
> Going forward, the CAP_SYS_ADMIN requirement will be different for
> some of these selection modes, which prompted me to at least list the
> different selection modes with a short description.  I am leaving
> CAP_SYS_ADMIN documentation as it is for now and will send another
> patch once these semantics are finalized [1] [2].
> 
> Thanks,
> –Günther
> 
> [1] <https://lore.kernel.org/all/20250221.0a947528d8f3@gnoack.org/>
> [2] <https://lore.kernel.org/all/20250223205449.7432-2-gnoack3000@gmail.com/>

Thanks!  I've applied both patches.  I've added Acked-by tags for Jared,
since there was a mail saying LGTM in the previos version, and it hasn't
changed significantly.


Have a lovely day!
Alex

> 
> History:
> 
> V2:
>  * Split into a "restructuring" and a "new documentation" commit
>  * Use non-breaking space \~
>  * Put URIs in <>
>  * Added a helpful link to console_codes(4) regarding mouse reporting
> 
> V3:
>  * Corrections and clarifications for various selection modes
>    as suggested by Jared Finder. (Thanks!)
> 
> V4:
>  * Clarified how TIOCL_SELPOINTER selects the coordinate to use
> 
> Günther Noack (2):
>   TIOCLINUX.2const: Restructure documentation for TIOCL_SETSEL selection
>     modes
>   TIOCLINUX.2const: Document missing TIOCL_SETSEL selection modes
> 
>  man/man2const/TIOCLINUX.2const | 59 +++++++++++++++++++++++++++++++---
>  1 file changed, 54 insertions(+), 5 deletions(-)
> 
> Range-diff against v3:
> 1:  d07edb528 = 1:  828c5189a TIOCLINUX.2const: Restructure documentation for TIOCL_SETSEL selection modes
> 2:  59f217fb0 ! 2:  bffc3e550 TIOCLINUX.2const: Document missing TIOCL_SETSEL selection modes
>     @@ man/man2const/TIOCLINUX.2const: Select line-by-line,
>      +.RI ( xs ,\~ ys )
>      +or
>      +.RI ( xe ,\~ ye ),
>     -+whichever is greater.
>     ++whichever is later in text flow order.
>      +.TP
>      +.B TIOCL_SELCLEAR
>      +Remove the current selection highlight, if any,
> -- 
> 2.49.0
> 

-- 
<https://www.alejandro-colomar.es/>

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