Re: [PATCH] Detect key modifier status in 'sleep --interruptible'

[Colin Watson <cjwatson@ubuntu.com>]

On Tue, Aug 25, 2009 at 12:02:17AM +0100, Colin Watson wrote:
> I'm open to other ideas. 'sleep --interruptible 0' is not an entirely
> natural way to express what I'm looking for, so I'm not particularly
> attached to it. 'if sleep --interruptible 0; then set timeout=0; fi' is
> suboptimal because it means that if either (a) core.img is too old to
> have getkeystatus support or (b) the current console driver does not
> support getkeystatus then the menu will be skipped without a way to
> access it at run-time. I'd much rather have something that allowed
> zero-timeout-with-Shift-to-access-menu if and only if we have a new
> enough core.img and the console driver has getkeystatus support, and
> otherwise degraded to something else sensible.

Here's yet another version, following a discussion with Robert on IRC. I
think that this now satisfies Vladimir's concerns about not breaking
platforms that don't have a usable getkeystatus, and my concerns about
backward compatibility with old core.img files. The new keystatus
command is, I think, also a rather clearer way to express this.

I expect to use this something like this:

  set timeout=10
  if keystatus; then
    if keystatus --shift; then
      true
    else
      set timeout=0
    fi
  fi

I left part of the sleep change in for some degree of consistency, but
removed the change to the case where the sleep period is zero. I also
adjusted the USB keyboard driver to tweak the idle rate temporarily to
make sure that we get events even if a modifier isn't pressed or
released during the timeout.

2009-08-24  Colin Watson  <cjwatson@ubuntu.com>
2009-08-24  Robert Millan  <rmh.grub@aybabtu.com>

	Add `getkeystatus' terminal method.  Use it in `sleep' to detect
	Shift being held down.  Add a new `keystatus' command to query
	it.

	* include/grub/term.h (GRUB_TERM_STATUS_SHIFT,
	GRUB_TERM_STATUS_CTRL, GRUB_TERM_STATUS_ALT): Definitions for
	modifier key bitmasks.
	(struct grub_term_input): Add `getkeystatus' member.
	(grub_getkeystatus): Add prototype.
	* kern/term.c (grub_getkeystatus): New function.

	* include/grub/i386/pc/memory.h
	(GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR): New macro.
	(struct grub_machine_bios_data_area): Define necessary parts of BIOS
	Data Area layout.
	* term/i386/pc/console.c (grub_console_getkeystatus): New function.
	(grub_console_term_input): Set `getkeystatus' member.
	* term/usb_keyboard.c (grub_usb_keyboard_getkeystatus): New
	function.
	(grub_usb_keyboard_term): Set `getkeystatus' member.

	* commands/sleep.c (grub_check_keyboard): New function.
	(grub_interruptible_millisleep): Use grub_check_keyboard,
	checking whether Shift is pressed in addition to checking for
	Escape.

	* commands/keystatus.c: New file.
	* conf/common.rmk (pkglib_MODULES): Add keystatus.mod.
	(keystatus_mod_SOURCES): New variable.
	(keystatus_mod_CFLAGS): Likewise.
	(keystatus_mod_LDFLAGS): Likewise.
	* conf/i386-coreboot.rmk (grub_emu_SOURCES): Add
	commands/keystatus.c.
	* conf/i386-efi.rmk (grub_emu_SOURCES): Likewise.
	* conf/i386-ieee1275.rmk (grub_emu_SOURCES): Likewise.
	* conf/i386-pc.rmk (grub_emu_SOURCES): Likewise.
	* conf/powerpc-ieee1275.rmk (grub_emu_SOURCES): Likewise.
	* conf/sparc64-ieee1275.rmk (grub_emu_SOURCES): Likewise.
	* conf/x86_64-efi.rmk (grub_emu_SOURCES): Likewise.
	* DISTLIST: Add commands/keystatus.c.

Index: conf/common.rmk
===================================================================
--- conf/common.rmk	(revision 2535)
+++ conf/common.rmk	(working copy)
@@ -363,7 +363,8 @@
 	terminfo.mod test.mod blocklist.mod hexdump.mod		\
 	read.mod sleep.mod loadenv.mod crc.mod parttool.mod	\
 	msdospart.mod memrw.mod normal.mod sh.mod lua.mod	\
-	gptsync.mod true.mod probe.mod password.mod
+	gptsync.mod true.mod probe.mod password.mod		\
+	keystatus.mod
 
 # For password.mod.
 password_mod_SOURCES = commands/password.c
@@ -510,6 +511,11 @@
 probe_mod_CFLAGS = $(COMMON_CFLAGS)
 probe_mod_LDFLAGS = $(COMMON_LDFLAGS)
 
+# For keystatus.mod.
+keystatus_mod_SOURCES = commands/keystatus.c
+keystatus_mod_CFLAGS = $(COMMON_CFLAGS)
+keystatus_mod_LDFLAGS = $(COMMON_LDFLAGS)
+
 # For normal.mod.
 normal_mod_SOURCES = normal/main.c normal/cmdline.c normal/dyncmd.c \
 	normal/auth.c normal/autofs.c normal/handler.c \
Index: conf/i386-pc.rmk
===================================================================
--- conf/i386-pc.rmk	(revision 2535)
+++ conf/i386-pc.rmk	(working copy)
@@ -123,7 +123,7 @@
 	lib/hexdump.c commands/i386/pc/halt.c commands/reboot.c		\
 	commands/gptsync.c commands/probe.c commands/xnu_uuid.c		\
 	commands/i386/cpuid.c	\
-	commands/password.c						\
+	commands/password.c commands/keystatus.c			\
 	disk/host.c disk/loopback.c disk/scsi.c				\
 	fs/fshelp.c 	\
 	\
Index: conf/i386-efi.rmk
===================================================================
--- conf/i386-efi.rmk	(revision 2535)
+++ conf/i386-efi.rmk	(working copy)
@@ -37,7 +37,7 @@
 	commands/configfile.c commands/help.c				\
 	commands/handler.c commands/ls.c commands/test.c 		\
 	commands/search.c commands/hexdump.c lib/hexdump.c		\
-	commands/halt.c commands/reboot.c				\
+	commands/halt.c commands/reboot.c commands/keystatus.c		\
 	commands/i386/cpuid.c						\
 	commands/password.c						\
 	disk/loopback.c							\
Index: conf/i386-ieee1275.rmk
===================================================================
--- conf/i386-ieee1275.rmk	(revision 2535)
+++ conf/i386-ieee1275.rmk	(working copy)
@@ -66,7 +66,7 @@
 	lib/hexdump.c commands/halt.c commands/reboot.c			\
 	commands/gptsync.c commands/probe.c  commands/xnu_uuid.c	\
 	commands/i386/cpuid.c	\
-	commands/password.c						\
+	commands/password.c commands/keystatus.c			\
 	disk/host.c disk/loopback.c					\
 	\
 	fs/affs.c fs/cpio.c fs/fat.c fs/ext2.c fs/hfs.c			\
Index: conf/x86_64-efi.rmk
===================================================================
--- conf/x86_64-efi.rmk	(revision 2535)
+++ conf/x86_64-efi.rmk	(working copy)
@@ -37,7 +37,7 @@
 	commands/search.c commands/hexdump.c lib/hexdump.c		\
 	commands/halt.c commands/reboot.c				\
 	commands/i386/cpuid.c						\
-	commands/password.c						\
+	commands/password.c commands/keystatus.c			\
 	disk/loopback.c							\
 	\
 	fs/affs.c fs/cpio.c fs/fat.c fs/ext2.c fs/hfs.c			\
Index: conf/i386-coreboot.rmk
===================================================================
--- conf/i386-coreboot.rmk	(revision 2535)
+++ conf/i386-coreboot.rmk	(working copy)
@@ -110,7 +110,7 @@
 	commands/handler.c commands/ls.c commands/test.c 		\
 	commands/search.c commands/blocklist.c commands/hexdump.c	\
 	commands/gptsync.c commands/probe.c commands/xnu_uuid.c		\
-	commands/password.c						\
+	commands/password.c commands/keystatus.c			\
 	lib/hexdump.c commands/i386/cpuid.c				\
 	disk/host.c disk/loopback.c					\
 	\
Index: conf/powerpc-ieee1275.rmk
===================================================================
--- conf/powerpc-ieee1275.rmk	(revision 2535)
+++ conf/powerpc-ieee1275.rmk	(working copy)
@@ -46,7 +46,7 @@
 	commands/ls.c commands/blocklist.c commands/hexdump.c		\
 	lib/hexdump.c commands/halt.c commands/reboot.c 		\
 	commands/gptsync.c commands/probe.c commands/xnu_uuid.c		\
-	commands/password.c						\
+	commands/password.c commands/keystatus.c			\
 	disk/loopback.c							\
 	\
 	fs/affs.c fs/cpio.c fs/fat.c fs/ext2.c fs/hfs.c			\
Index: conf/sparc64-ieee1275.rmk
===================================================================
--- conf/sparc64-ieee1275.rmk	(revision 2535)
+++ conf/sparc64-ieee1275.rmk	(working copy)
@@ -103,7 +103,7 @@
 	commands/ls.c commands/blocklist.c commands/hexdump.c		\
 	lib/hexdump.c commands/halt.c commands/reboot.c 		\
 	commands/gptsync.c commands/probe.c commands/xnu_uuid.c		\
-	commands/password.c						\
+	commands/password.c commands/keystatus.c			\
 	disk/loopback.c							\
 	\
 	fs/affs.c fs/cpio.c fs/fat.c fs/ext2.c fs/hfs.c			\
Index: kern/term.c
===================================================================
--- kern/term.c	(revision 2535)
+++ kern/term.c	(working copy)
@@ -140,6 +140,15 @@
   return (grub_cur_term_input->checkkey) ();
 }
 
+int
+grub_getkeystatus (void)
+{
+  if (grub_cur_term_input->getkeystatus)
+    return (grub_cur_term_input->getkeystatus) ();
+  else
+    return 0;
+}
+
 grub_uint16_t
 grub_getxy (void)
 {
Index: include/grub/term.h
===================================================================
--- include/grub/term.h	(revision 2535)
+++ include/grub/term.h	(working copy)
@@ -1,6 +1,6 @@
 /*
  *  GRUB  --  GRand Unified Bootloader
- *  Copyright (C) 2002,2003,2005,2007,2008  Free Software Foundation, Inc.
+ *  Copyright (C) 2002,2003,2005,2007,2008,2009  Free Software Foundation, Inc.
  *
  *  GRUB is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -72,6 +72,12 @@
 #define GRUB_TERM_NEED_INIT	(1 << 16)
 
 
+/* Bitmasks for modifier keys returned by grub_getkeystatus.  */
+#define GRUB_TERM_STATUS_SHIFT	(1 << 0)
+#define GRUB_TERM_STATUS_CTRL	(1 << 1)
+#define GRUB_TERM_STATUS_ALT	(1 << 2)
+
+
 /* Unicode characters for fancy graphics.  */
 #define GRUB_TERM_DISP_LEFT	0x2190
 #define GRUB_TERM_DISP_UP	0x2191
@@ -157,6 +163,9 @@
 
   /* Get a character.  */
   int (*getkey) (void);
+
+  /* Get keyboard modifier status.  */
+  int (*getkeystatus) (void);
 };
 typedef struct grub_term_input *grub_term_input_t;
 
@@ -275,6 +284,7 @@
 grub_ssize_t EXPORT_FUNC(grub_getcharwidth) (grub_uint32_t code);
 int EXPORT_FUNC(grub_getkey) (void);
 int EXPORT_FUNC(grub_checkkey) (void);
+int EXPORT_FUNC(grub_getkeystatus) (void);
 grub_uint16_t EXPORT_FUNC(grub_getwh) (void);
 grub_uint16_t EXPORT_FUNC(grub_getxy) (void);
 void EXPORT_FUNC(grub_gotoxy) (grub_uint8_t x, grub_uint8_t y);
Index: include/grub/i386/pc/memory.h
===================================================================
--- include/grub/i386/pc/memory.h	(revision 2535)
+++ include/grub/i386/pc/memory.h	(working copy)
@@ -78,8 +78,19 @@
 /* The data segment of the pseudo real mode.  */
 #define GRUB_MEMORY_MACHINE_PSEUDO_REAL_DSEG	0x20
 
+#define GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR	0x400
+
 #ifndef ASM_FILE
 
+/* See http://heim.ifi.uio.no/~stanisls/helppc/bios_data_area.html for a
+   description of the BIOS Data Area layout.  */
+struct grub_machine_bios_data_area
+{
+  grub_uint8_t unused1[0x17];
+  grub_uint8_t keyboard_flag_lower; /* 0x17 */ 
+  grub_uint8_t unused2[0xf0 - 0x18];
+};
+
 struct grub_machine_mmap_entry
 {
   grub_uint32_t size;
Index: commands/sleep.c
===================================================================
--- commands/sleep.c	(revision 2535)
+++ commands/sleep.c	(working copy)
@@ -1,7 +1,7 @@
 /* sleep.c - Command to wait a specified number of seconds.  */
 /*
  *  GRUB  --  GRand Unified Bootloader
- *  Copyright (C) 2006,2007,2008  Free Software Foundation, Inc.
+ *  Copyright (C) 2006,2007,2008,2009  Free Software Foundation, Inc.
  *
  *  GRUB is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -43,6 +43,20 @@
   grub_printf ("%d    ", n);
 }
 
+static int
+grub_check_keyboard (void)
+{
+  int mods = grub_getkeystatus ();
+  if (mods >= 0 && (mods & GRUB_TERM_STATUS_SHIFT) != 0)
+    return 1;
+
+  if (grub_checkkey () >= 0 &&
+      GRUB_TERM_ASCII_CHAR (grub_getkey ()) == GRUB_TERM_ESC)
+    return 1;
+
+  return 0;
+}
+
 /* Based on grub_millisleep() from kern/generic/millisleep.c.  */
 static int
 grub_interruptible_millisleep (grub_uint32_t ms)
@@ -52,8 +66,7 @@
   start = grub_get_time_ms ();
 
   while (grub_get_time_ms () - start < ms)
-    if (grub_checkkey () >= 0 &&
-	GRUB_TERM_ASCII_CHAR (grub_getkey ()) == GRUB_TERM_ESC)
+    if (grub_check_keyboard ())
       return 1;
 
   return 0;
Index: commands/keystatus.c
===================================================================
--- commands/keystatus.c	(revision 0)
+++ commands/keystatus.c	(revision 0)
@@ -0,0 +1,81 @@
+/* keystatus.c - Command to check key modifier status.  */
+/*
+ *  GRUB  --  GRand Unified Bootloader
+ *  Copyright (C) 2009  Free Software Foundation, Inc.
+ *
+ *  GRUB is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *
+ *  GRUB is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <grub/dl.h>
+#include <grub/misc.h>
+#include <grub/extcmd.h>
+#include <grub/term.h>
+
+static const struct grub_arg_option options[] =
+  {
+    {"shift", 's', 0, "check Shift key", 0, 0},
+    {"ctrl", 'c', 0, "check Control key", 0, 0},
+    {"alt", 'a', 0, "check Alt key", 0, 0},
+    {0, 0, 0, 0, 0, 0}
+  };
+
+#define grub_cur_term_input	grub_term_get_current_input ()
+
+static grub_err_t
+grub_cmd_keystatus (grub_extcmd_t cmd,
+		    int argc __attribute__ ((unused)),
+		    char **args __attribute__ ((unused)))
+{
+  struct grub_arg_list *state = cmd->state;
+  int expect_mods = 0;
+  int mods;
+
+  if (state[0].set)
+    expect_mods |= GRUB_TERM_STATUS_SHIFT;
+  if (state[1].set)
+    expect_mods |= GRUB_TERM_STATUS_CTRL;
+  if (state[2].set)
+    expect_mods |= GRUB_TERM_STATUS_ALT;
+
+  /* Without arguments, just check whether getkeystatus is supported at
+     all.  */
+  if (!grub_cur_term_input->getkeystatus)
+    return grub_error (GRUB_ERR_TEST_FAILURE, "false");
+  grub_dprintf ("keystatus", "expect_mods: %d\n", expect_mods);
+  if (!expect_mods)
+    return 0;
+
+  mods = grub_getkeystatus ();
+  grub_dprintf ("keystatus", "mods: %d\n", mods);
+  if (mods >= 0 && (mods & expect_mods) != 0)
+    return 0;
+  else
+    return grub_error (GRUB_ERR_TEST_FAILURE, "false");
+}
+
+static grub_extcmd_t cmd;
+\f
+GRUB_MOD_INIT(keystatus)
+{
+  cmd = grub_register_extcmd ("keystatus", grub_cmd_keystatus,
+			      GRUB_COMMAND_FLAG_BOTH,
+			      "keystatus [--shift|--ctrl|--alt]",
+			      "Check key modifier status",
+			      options);
+}
+
+GRUB_MOD_FINI(keystatus)
+{
+  grub_unregister_extcmd (cmd);
+}
Index: term/i386/pc/console.c
===================================================================
--- term/i386/pc/console.c	(revision 2535)
+++ term/i386/pc/console.c	(working copy)
@@ -1,6 +1,6 @@
 /*
  *  GRUB  --  GRand Unified Bootloader
- *  Copyright (C) 2002,2003,2005,2007,2008  Free Software Foundation, Inc.
+ *  Copyright (C) 2002,2003,2005,2007,2008,2009  Free Software Foundation, Inc.
  *
  *  GRUB is free software: you can redistribute it and/or modify
  *  it under the terms of the GNU General Public License as published by
@@ -16,15 +16,35 @@
  *  along with GRUB.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <grub/machine/memory.h>
 #include <grub/machine/console.h>
 #include <grub/term.h>
 #include <grub/types.h>
 
+static const struct grub_machine_bios_data_area *bios_data_area = GRUB_MEMORY_MACHINE_BIOS_DATA_AREA_ADDR;
+
+static int
+grub_console_getkeystatus (void)
+{
+  grub_uint8_t status = bios_data_area->keyboard_flag_lower;
+  int mods = 0;
+
+  if (status & 0x03)
+    mods |= GRUB_TERM_STATUS_SHIFT;
+  if (status & 0x04)
+    mods |= GRUB_TERM_STATUS_CTRL;
+  if (status & 0x08)
+    mods |= GRUB_TERM_STATUS_ALT;
+
+  return mods;
+}
+
 static struct grub_term_input grub_console_term_input =
   {
     .name = "console",
     .checkkey = grub_console_checkkey,
     .getkey = grub_console_getkey,
+    .getkeystatus = grub_console_getkeystatus,
   };
 
 static struct grub_term_output grub_console_term_output =
Index: term/usb_keyboard.c
===================================================================
--- term/usb_keyboard.c	(revision 2535)
+++ term/usb_keyboard.c	(working copy)
@@ -238,11 +238,67 @@
   return key;
 }
 
+static int
+grub_usb_keyboard_getkeystatus (void)
+{
+  grub_uint8_t data[8];
+  int mods = 0;
+  grub_err_t err;
+  grub_uint64_t currtime;
+  int timeout = 50;
+
+  /* Set idle time to the minimum offered by the spec (4 milliseconds) so
+     that we can find out the current state.  */
+  grub_usb_control_msg (usbdev, 0x21, 0x0A, 1<<8, 0, 0, 0);
+
+  grub_usb_control_msg (usbdev, (1 << 7) | (1 << 5) | 1, 0x02, 0, 0, 1, (char *) data);
+
+  currtime = grub_get_time_ms ();
+  do
+    {
+      /* Get_Report.  */
+      err = grub_usb_keyboard_getreport (usbdev, data);
+
+      /* Implement a timeout.  */
+      if (grub_get_time_ms () > currtime + timeout)
+	break;
+    }
+  while (err || !data[0]);
+
+  /* Go back to reporting every time an event occurs and not more often than
+     that.  */
+  grub_usb_control_msg (usbdev, 0x21, 0x0A, 0<<8, 0, 0, 0);
+
+  /* We allowed a while for modifiers to show up in the report, but it is
+     not an error if they never did.  */
+  if (err)
+    return -1;
+
+  grub_dprintf ("usb_keyboard",
+		"report: 0x%02x 0x%02x 0x%02x 0x%02x"
+		" 0x%02x 0x%02x 0x%02x 0x%02x\n",
+		data[0], data[1], data[2], data[3],
+		data[4], data[5], data[6], data[7]);
+
+  /* Check Shift, Control, and Alt status.  */
+  if (data[0] & 0x02 || data[0] & 0x20)
+    mods |= GRUB_TERM_STATUS_SHIFT;
+  if (data[0] & 0x01 || data[0] & 0x10)
+    mods |= GRUB_TERM_STATUS_CTRL;
+  if (data[0] & 0x04 || data[0] & 0x40)
+    mods |= GRUB_TERM_STATUS_ALT;
+
+  grub_errno = GRUB_ERR_NONE;
+
+  return mods;
+}
+
 static struct grub_term_input grub_usb_keyboard_term =
   {
     .name = "usb_keyboard",
     .checkkey = grub_usb_keyboard_checkkey,
     .getkey = grub_usb_keyboard_getkey,
+    .getkeystatus = grub_usb_keyboard_getkeystatus,
     .next = 0
   };
 

-- 
Colin Watson                           [cjwatson@chiark.greenend.org.uk]