console.c File Reference

#include "stddef.h"
#include "console.h"
#include <gpxe/process.h>
#include <gpxe/nap.h>

Go to the source code of this file.

Functions
	FILE_LICENCE (GPL2_OR_LATER)
void	putchar (int character)
	Write a single character to each console device.
static struct console_driver *	has_input (void)
	Check to see if any input is available on any console.
int	getchar (void)
	Read a single character from any console.
int	iskey (void)
	Check for available input on any console.

---

Detailed Description

Definition in file console.c.

---

Function Documentation

FILE_LICENCE

(

GPL2_OR_LATER

)

void putchar

(

int

character

)

Write a single character to each console device.

Parameters:

character

Character to be written

Return values:

None

-

Exceptions:

None

-

The character is written out to all enabled console devices, using each device's console_driver::putchar() method.

Definition at line 21 of file console.c.

References CONSOLES, console_driver::disabled, for_each_table_entry, console_driver::putchar, and putchar().

Referenced by ansiscr_putc(), clrline(), eepro_poll(), epic100_open(), falcon_init_xmac(), get_eeprom_data(), int21(), print_user_string(), printf_putchar(), putchar(), readline(), and sync_console().

                               {
        struct console_driver *console;

        /* Automatic LF -> CR,LF translation */
        if ( character == '\n' )
                putchar ( '\r' );

        for_each_table_entry ( console, CONSOLES ) {
                if ( ( ! console->disabled ) && console->putchar )
                        console->putchar ( character );
        }
}

static struct console_driver* has_input

(

void

)

[static, read]

Check to see if any input is available on any console.

Parameters:

None

-

Return values:

	console	Console device that has input available, if any.
	NULL	No console device has input available.

Exceptions:

None

-

All enabled console devices are checked once for available input using each device's console_driver::iskey() method. The first console device that has available input will be returned, if any.

Definition at line 47 of file console.c.

References CONSOLES, console_driver::disabled, for_each_table_entry, console_driver::iskey, and NULL.

Referenced by getchar(), and iskey().

                                                  {
        struct console_driver *console;

        for_each_table_entry ( console, CONSOLES ) {
                if ( ( ! console->disabled ) && console->iskey ) {
                        if ( console->iskey () )
                                return console;
                }
        }
        return NULL;
}

int getchar

(

void

)

Read a single character from any console.

Parameters:

None

-

Return values:

character

Character read from a console.

Exceptions:

None

-

A character will be read from the first enabled console device that has input available using that console's console_driver::getchar() method. If no console has input available to be read, this method will block. To perform a non-blocking read, use something like

   int key = iskey() ? getchar() : -1;

The character read will not be echoed back to any console.

Definition at line 80 of file console.c.

References cpu_nap(), console_driver::getchar, has_input(), and step().

Referenced by ansiscr_getc(), getchar_timeout(), getkey(), iflinkwait(), int21(), monojob_wait(), more(), pause(), and shell_banner().

                     {
        struct console_driver *console;
        int character;

        while ( 1 ) {
                console = has_input();
                if ( console && console->getchar ) {
                        character = console->getchar ();
                        break;
                }

                /* Doze for a while (until the next interrupt).  This works
                 * fine, because the keyboard is interrupt-driven, and the
                 * timer interrupt (approx. every 50msec) takes care of the
                 * serial port, which is read by polling.  This reduces the
                 * power dissipation of a modern CPU considerably, and also
                 * makes Etherboot waiting for user interaction waste a lot
                 * less CPU time in a VMware session.
                 */
                cpu_nap();

                /* Keep processing background tasks while we wait for
                 * input.
                 */
                step();
        }

        /* CR -> LF translation */
        if ( character == '\r' )
                character = '\n';

        return character;
}

int iskey

(

void

)

Check for available input on any console.

Parameters:

None

-

Return values:

	True	Input is available on a console
	False	Input is not available on any console

Exceptions:

None

-

All enabled console devices are checked once for available input using each device's console_driver::iskey() method. If any console device has input available, this call will return True. If this call returns True, you can then safely call getchar() without blocking.

Definition at line 128 of file console.c.

References has_input().

Referenced by ansiscr_peek(), getchar_timeout(), iflinkwait(), int21(), monojob_wait(), pxe_menu_prompt_and_select(), pxe_menu_select(), and shell_banner().

                   {
        return has_input() ? 1 : 0;
}