int13con.c File Reference

INT13 disk log console. More...

#include <stdint.h>
#include <string.h>
#include <errno.h>
#include <ipxe/console.h>
#include <ipxe/init.h>
#include <realmode.h>
#include <int13.h>
#include <config/console.h>

Go to the source code of this file.

Data Structures
struct	int13con_header
	Log partition header. More...

Macros
#define	CONSOLE_INT13   ( CONSOLE_USAGE_ALL & ~CONSOLE_USAGE_LOG )
#define	INT13CON_DRIVE   0x80
	Disk drive number. More...
#define	INT13CON_PARTITION_TYPE   0xe0
	Log partition type. More...
#define	INT13CON_MAX_UNWRITTEN   64
	Maximum number of outstanding unwritten characters. More...
#define	INT13CON_MAGIC   "iPXE LOG\n\n"
	Log partition magic signature. More...
#define	int13con_vector   __use_data16 ( int13con_vector )
#define	int13con_buffer   __use_data16 ( int13con_buffer )
#define	int13con_address   __use_data16 ( int13con_address )

Functions
	FILE_LICENCE (GPL2_OR_LATER_OR_UBDL)
static struct segoff	__bss16 (int13con_vector)
	Original INT13 vector. More...
static uint8_t	__bss16_array (int13con_buffer, [INT13_BLKSIZE])
	Sector buffer. More...
static struct int13_disk_address	__bss16 (int13con_address)
	Disk address packet. More...
static int	int13con_rw (unsigned int op, uint64_t lba)
	Read/write disk sector. More...
static void	int13con_putchar (int character)
	Write character to console. More...
static int	int13con_find (void)
	Find log partition. More...
static void	int13con_init (void)
	Initialise INT13 console. More...
struct init_fn int13con_init_fn	__init_fn (INIT_CONSOLE)
	INT13 console initialisation function. More...

Variables
static uint64_t	int13con_lba
	Current LBA. More...
static uint64_t	int13con_max_lba
	Maximum LBA. More...
static size_t	int13con_offset
	Current offset within sector. More...
static size_t	int13con_unwritten
	Number of unwritten characters. More...
struct console_driver int13con	__console_driver
	INT13 console driver. More...

Detailed Description

INT13 disk log console.

Definition in file int13con.c.

Macro Definition Documentation

CONSOLE_INT13

#define CONSOLE_INT13   ( CONSOLE_USAGE_ALL & ~CONSOLE_USAGE_LOG )

Definition at line 44 of file int13con.c.

INT13CON_DRIVE

#define INT13CON_DRIVE   0x80

Disk drive number.

Definition at line 48 of file int13con.c.

INT13CON_PARTITION_TYPE

#define INT13CON_PARTITION_TYPE   0xe0

Log partition type.

Definition at line 51 of file int13con.c.

INT13CON_MAX_UNWRITTEN

#define INT13CON_MAX_UNWRITTEN   64

Maximum number of outstanding unwritten characters.

Definition at line 54 of file int13con.c.

INT13CON_MAGIC

#define INT13CON_MAGIC   "iPXE LOG\n\n"

Log partition magic signature.

Definition at line 63 of file int13con.c.

int13con_vector

#define int13con_vector   __use_data16 ( int13con_vector )

Definition at line 67 of file int13con.c.

int13con_buffer

#define int13con_buffer   __use_data16 ( int13con_buffer )

Definition at line 71 of file int13con.c.

int13con_address

#define int13con_address   __use_data16 ( int13con_address )

Definition at line 75 of file int13con.c.

Function Documentation

FILE_LICENCE()

FILE_LICENCE

(

GPL2_OR_LATER_OR_UBDL

)

__bss16() [1/2]

static struct segoff __bss16 ( int13con_vector  )

static

Original INT13 vector.

__bss16_array()

static uint8_t __bss16_array ( int13con_buffer  )

static

Sector buffer.

__bss16() [2/2]

static struct int13_disk_address __bss16 ( int13con_address  )

static

Disk address packet.

int13con_rw()

static int int13con_rw ( unsigned int  op, uint64_t  lba  )

static

Read/write disk sector.

Parameters

op	Operation
lba	Logical block address

Return values

rc	Return status code

Definition at line 98 of file int13con.c.

                                                         {
        uint8_t error;

        /* Construct disk address packet */
        int13con_address.bufsize = sizeof ( int13con_address );
        int13con_address.count = 1;
        int13con_address.buffer.segment = rm_ds;
        int13con_address.buffer.offset = __from_data16 ( int13con_buffer );
        int13con_address.lba = lba;

        /* Emulate INT13 via original vector.  We do this since iPXE
         * (or another subsequent bootloader) may hook INT13 and remap
         * drive numbers.
         */
        __asm__ ( REAL_CODE ( "pushfw\n\t"
                              "cli\n\t"
                              "lcall *int13con_vector\n\t" )
                  : "=a" ( error )
                  : "0" ( op << 8 ), "d" ( INT13CON_DRIVE ),
                    "S" ( __from_data16 ( &int13con_address ) ) );
        if ( error ) {
                DBG ( "INT13CON operation %04x failed: %02x\n",
                      op, error );
                return -EIO;
        }

        return 0;
}

References __asm__(), __from_data16, DBG, EIO, error, int13con_address, int13con_buffer, INT13CON_DRIVE, lba, op, REAL_CODE, and rm_ds.

Referenced by int13con_find(), and int13con_putchar().

int13con_putchar()

static void int13con_putchar ( int  character )

static

Write character to console.

Parameters

character

Character

Definition at line 132 of file int13con.c.

                                               {
        static int busy;
        int rc;

        /* Ignore if we are already mid-logging */
        if ( busy )
                return;
        busy = 1;

        /* Write character to buffer */
        int13con_buffer[int13con_offset++] = character;
        int13con_unwritten++;

        /* Write sector to disk, if applicable */
        if ( ( int13con_offset == INT13_BLKSIZE ) ||
             ( int13con_unwritten == INT13CON_MAX_UNWRITTEN ) ||
             ( character == '\n' ) ) {

                /* Write sector to disk */
                if ( ( rc = int13con_rw ( INT13_EXTENDED_WRITE,
                                          int13con_lba ) ) != 0 ) {
                        DBG ( "INT13CON could not write log\n" );
                        /* Ignore and continue; there's nothing we can do */
                }

                /* Reset count of unwritten characters */
                int13con_unwritten = 0;
        }

        /* Move to next sector, if applicable */
        if ( int13con_offset == INT13_BLKSIZE ) {

                /* Disable console if we have run out of space */
                if ( int13con_lba >= int13con_max_lba )
                        int13con.disabled = 1;

                /* Clear log buffer */
                memset ( int13con_buffer, 0, sizeof ( int13con_buffer ) );
                int13con_offset = 0;

                /* Move to next sector */
                int13con_lba++;
        }

        /* Clear busy flag */
        busy = 0;
}

References DBG, INT13_BLKSIZE, INT13_EXTENDED_WRITE, int13con_buffer, int13con_lba, int13con_max_lba, INT13CON_MAX_UNWRITTEN, int13con_offset, int13con_rw(), int13con_unwritten, memset(), and rc.

int13con_find()

static int int13con_find ( void  )

static

Find log partition.

Return values

rc	Return status code

Definition at line 185 of file int13con.c.

                                  {
        struct master_boot_record *mbr =
                ( ( struct master_boot_record * ) int13con_buffer );
        struct int13con_header *hdr =
                ( ( struct int13con_header * ) int13con_buffer );
        struct partition_table_entry part[4];
        unsigned int i;
        int rc;

        /* Read MBR */
        if ( ( rc = int13con_rw ( INT13_EXTENDED_READ, 0 ) ) != 0 ) {
                DBG ( "INT13CON could not read MBR: %s\n", strerror ( rc ) );
                return rc;
        }

        /* Check MBR magic */
        if ( mbr->magic != INT13_MBR_MAGIC ) {
                DBG ( "INT13CON incorrect MBR magic\n" );
                DBG2_HDA ( 0, mbr, sizeof ( *mbr ) );
                return -EINVAL;
        }

        /* Look for magic partition */
        memcpy ( part, mbr->partitions, sizeof ( part ) );
        for ( i = 0 ; i < ( sizeof ( part ) / sizeof ( part[0] ) ) ; i++ ) {

                /* Skip partitions of the wrong type */
                if ( part[i].type != INT13CON_PARTITION_TYPE )
                        continue;

                /* Read partition header */
                if ( ( rc = int13con_rw ( INT13_EXTENDED_READ,
                                          part[i].start ) ) != 0 ) {
                        DBG ( "INT13CON partition %d could not read header: "
                              "%s\n", ( i + 1 ), strerror ( rc ) );
                        continue;
                }

                /* Check partition header */
                if ( memcmp ( hdr->magic, INT13CON_MAGIC,
                              sizeof ( hdr->magic ) ) != 0 ) {
                        DBG ( "INT13CON partition %d bad magic\n", ( i + 1 ) );
                        DBG2_HDA ( 0, hdr, sizeof ( *hdr ) );
                        continue;
                }

                /* Found log partition */
                DBG ( "INT13CON partition %d at [%08x,%08x)\n", ( i + 1 ),
                      part[i].start, ( part[i].start + part[i].length ) );
                int13con_lba = part[i].start;
                int13con_max_lba = ( part[i].start + part[i].length - 1 );

                /* Initialise log buffer */
                memset ( &int13con_buffer[ sizeof ( *hdr ) ], 0,
                         ( sizeof ( int13con_buffer ) - sizeof ( *hdr ) ) );
                int13con_offset = sizeof ( hdr->magic );

                return 0;
        }

        DBG ( "INT13CON found no log partition\n" );
        return -ENOENT;
}

References DBG, DBG2_HDA, EINVAL, ENOENT, hdr, INT13_EXTENDED_READ, INT13_MBR_MAGIC, int13con_buffer, int13con_lba, INT13CON_MAGIC, int13con_max_lba, int13con_offset, INT13CON_PARTITION_TYPE, int13con_rw(), length, partition_table_entry::length, master_boot_record::magic, memcmp(), memcpy(), memset(), master_boot_record::partitions, rc, start, partition_table_entry::start, strerror(), and type.

Referenced by int13con_init().

int13con_init()

static void int13con_init ( void  )

static

Initialise INT13 console.

Definition at line 253 of file int13con.c.

                                   {
        uint8_t error;
        uint16_t check;
        unsigned int discard_c;
        unsigned int discard_d;
        int rc;

        /* Check for INT13 extensions */
        __asm__ __volatile__ ( REAL_CODE ( "int $0x13\n\t"
                                           "setc %%al\n\t" )
                               : "=a" ( error ), "=b" ( check ),
                                 "=c" ( discard_c ), "=d" ( discard_d )
                               : "0" ( INT13_EXTENSION_CHECK << 8 ),
                                 "1" ( 0x55aa ), "3" ( INT13CON_DRIVE ) );
        if ( error || ( check != 0xaa55 ) ) {
                DBG ( "INT13CON missing extensions (%02x,%04x)\n",
                      error, check );
                return;
        }

        /* Store original INT13 vector */
        copy_from_real ( &int13con_vector, 0, ( 0x13 * 4 ),
                         sizeof ( int13con_vector ) );
        DBG ( "INT13CON using original INT13 vector %04x:%04x\n",
              int13con_vector.segment, int13con_vector.offset );

        /* Locate log partition */
        if ( ( rc = int13con_find() ) != 0)
                return;

        /* Enable console */
        int13con.disabled = 0;
}

References __asm__(), __volatile__(), copy_from_real, DBG, discard_c, error, INT13_EXTENSION_CHECK, INT13CON_DRIVE, int13con_find(), int13con_vector, rc, and REAL_CODE.

__init_fn()

struct init_fn int13con_init_fn __init_fn

(

INIT_CONSOLE

)

INT13 console initialisation function.

Variable Documentation

int13con_lba

uint64_t int13con_lba

static

Current LBA.

Definition at line 78 of file int13con.c.

Referenced by int13con_find(), and int13con_putchar().

int13con_max_lba

uint64_t int13con_max_lba

static

Maximum LBA.

Definition at line 81 of file int13con.c.

Referenced by int13con_find(), and int13con_putchar().

int13con_offset

size_t int13con_offset

static

Current offset within sector.

Definition at line 84 of file int13con.c.

Referenced by int13con_find(), and int13con_putchar().

int13con_unwritten

size_t int13con_unwritten

static

Number of unwritten characters.

Definition at line 87 of file int13con.c.

Referenced by int13con_putchar().

__console_driver

struct console_driver int13con __console_driver

Initial value:

= {
        .putchar = int13con_putchar,
        .disabled = CONSOLE_DISABLED,
        .usage = CONSOLE_INT13,
}

INT13 console driver.

Definition at line 89 of file int13con.c.