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huntedbytheirs
2026-08-23 00:38:40 -04:00
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GRUB2/MOD_SRC/grub-2.04/grub-core/disk/i386/pc/biosdisk.c
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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 1999,2000,2001,2002,2003,2004,2005,2006,2007,2008,2009,2010 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/machine/biosdisk.h>
#include <grub/machine/kernel.h>
#include <grub/machine/memory.h>
#include <grub/machine/int.h>
#include <grub/disk.h>
#include <grub/dl.h>
#include <grub/mm.h>
#include <grub/types.h>
#include <grub/misc.h>
#include <grub/err.h>
#include <grub/term.h>
#include <grub/i18n.h>
GRUB_MOD_LICENSE ("GPLv3+");
static int cd_drive = 0;
static int grub_biosdisk_rw_int13_extensions (int ah, int drive, void *dap);
static int grub_biosdisk_get_num_floppies (void)
{
struct grub_bios_int_registers regs;
int drive;
/* reset the disk system first */
regs.eax = 0;
regs.edx = 0;
regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
grub_bios_interrupt (0x13, &regs);
for (drive = 0; drive < 2; drive++)
{
regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT | GRUB_CPU_INT_FLAGS_CARRY;
regs.edx = drive;
/* call GET DISK TYPE */
regs.eax = 0x1500;
grub_bios_interrupt (0x13, &regs);
if (regs.flags & GRUB_CPU_INT_FLAGS_CARRY)
break;
/* check if this drive exists */
if (!(regs.eax & 0x300))
break;
}
return drive;
}
/*
* Call IBM/MS INT13 Extensions (int 13 %ah=AH) for DRIVE. DAP
* is passed for disk address packet. If an error occurs, return
* non-zero, otherwise zero.
*/
static int
grub_biosdisk_rw_int13_extensions (int ah, int drive, void *dap)
{
struct grub_bios_int_registers regs;
regs.eax = ah << 8;
/* compute the address of disk_address_packet */
regs.ds = (((grub_addr_t) dap) & 0xffff0000) >> 4;
regs.esi = (((grub_addr_t) dap) & 0xffff);
regs.edx = drive;
regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
grub_bios_interrupt (0x13, &regs);
return (regs.eax >> 8) & 0xff;
}
/*
* Call standard and old INT13 (int 13 %ah=AH) for DRIVE. Read/write
* NSEC sectors from COFF/HOFF/SOFF into SEGMENT. If an error occurs,
* return non-zero, otherwise zero.
*/
static int
grub_biosdisk_rw_standard (int ah, int drive, int coff, int hoff,
int soff, int nsec, int segment)
{
int ret, i;
/* Try 3 times. */
for (i = 0; i < 3; i++)
{
struct grub_bios_int_registers regs;
/* set up CHS information */
/* set %ch to low eight bits of cylinder */
regs.ecx = (coff << 8) & 0xff00;
/* set bits 6-7 of %cl to high two bits of cylinder */
regs.ecx |= (coff >> 2) & 0xc0;
/* set bits 0-5 of %cl to sector */
regs.ecx |= soff & 0x3f;
/* set %dh to head and %dl to drive */
regs.edx = (drive & 0xff) | ((hoff << 8) & 0xff00);
/* set %ah to AH */
regs.eax = (ah << 8) & 0xff00;
/* set %al to NSEC */
regs.eax |= nsec & 0xff;
regs.ebx = 0;
regs.es = segment;
regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
grub_bios_interrupt (0x13, &regs);
/* check if successful */
if (!(regs.flags & GRUB_CPU_INT_FLAGS_CARRY))
return 0;
/* save return value */
ret = regs.eax >> 8;
/* if fail, reset the disk system */
regs.eax = 0;
regs.edx = (drive & 0xff);
regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
grub_bios_interrupt (0x13, &regs);
}
return ret;
}
/*
* Check if LBA is supported for DRIVE. If it is supported, then return
* the major version of extensions, otherwise zero.
*/
static int
grub_biosdisk_check_int13_extensions (int drive)
{
struct grub_bios_int_registers regs;
regs.edx = drive & 0xff;
regs.eax = 0x4100;
regs.ebx = 0x55aa;
regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
grub_bios_interrupt (0x13, &regs);
if (regs.flags & GRUB_CPU_INT_FLAGS_CARRY)
return 0;
if ((regs.ebx & 0xffff) != 0xaa55)
return 0;
/* check if AH=0x42 is supported */
if (!(regs.ecx & 1))
return 0;
return (regs.eax >> 8) & 0xff;
}
/*
* Return the geometry of DRIVE in CYLINDERS, HEADS and SECTORS. If an
* error occurs, then return non-zero, otherwise zero.
*/
static int
grub_biosdisk_get_diskinfo_standard (int drive,
unsigned long *cylinders,
unsigned long *heads,
unsigned long *sectors)
{
struct grub_bios_int_registers regs;
regs.eax = 0x0800;
regs.edx = drive & 0xff;
regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
grub_bios_interrupt (0x13, &regs);
/* Check if unsuccessful. Ignore return value if carry isn't set to
workaround some buggy BIOSes. */
if ((regs.flags & GRUB_CPU_INT_FLAGS_CARRY) && ((regs.eax & 0xff00) != 0))
return (regs.eax & 0xff00) >> 8;
/* bogus BIOSes may not return an error number */
/* 0 sectors means no disk */
if (!(regs.ecx & 0x3f))
/* XXX 0x60 is one of the unused error numbers */
return 0x60;
/* the number of heads is counted from zero */
*heads = ((regs.edx >> 8) & 0xff) + 1;
*cylinders = (((regs.ecx >> 8) & 0xff) | ((regs.ecx << 2) & 0x0300)) + 1;
*sectors = regs.ecx & 0x3f;
return 0;
}
static int
grub_biosdisk_get_diskinfo_real (int drive, void *drp, grub_uint16_t ax)
{
struct grub_bios_int_registers regs;
regs.eax = ax;
/* compute the address of drive parameters */
regs.esi = ((grub_addr_t) drp) & 0xf;
regs.ds = ((grub_addr_t) drp) >> 4;
regs.edx = drive & 0xff;
regs.flags = GRUB_CPU_INT_FLAGS_DEFAULT;
grub_bios_interrupt (0x13, &regs);
/* Check if unsuccessful. Ignore return value if carry isn't set to
workaround some buggy BIOSes. */
if ((regs.flags & GRUB_CPU_INT_FLAGS_CARRY) && ((regs.eax & 0xff00) != 0))
return (regs.eax & 0xff00) >> 8;
return 0;
}
/*
* Return the cdrom information of DRIVE in CDRP. If an error occurs,
* then return non-zero, otherwise zero.
*/
static int
grub_biosdisk_get_cdinfo_int13_extensions (int drive, void *cdrp)
{
return grub_biosdisk_get_diskinfo_real (drive, cdrp, 0x4b01);
}
/*
* Return the geometry of DRIVE in a drive parameters, DRP. If an error
* occurs, then return non-zero, otherwise zero.
*/
static int
grub_biosdisk_get_diskinfo_int13_extensions (int drive, void *drp)
{
return grub_biosdisk_get_diskinfo_real (drive, drp, 0x4800);
}
static int
grub_biosdisk_get_drive (const char *name)
{
unsigned long drive;
if (name[0] == 'c' && name[1] == 'd' && name[2] == 0 && cd_drive)
return cd_drive;
if ((name[0] != 'f' && name[0] != 'h') || name[1] != 'd')
goto fail;
drive = grub_strtoul (name + 2, 0, 10);
if (grub_errno != GRUB_ERR_NONE)
goto fail;
if (name[0] == 'h')
drive += 0x80;
return (int) drive ;
fail:
grub_error (GRUB_ERR_UNKNOWN_DEVICE, "not a biosdisk");
return -1;
}
static int
grub_biosdisk_call_hook (grub_disk_dev_iterate_hook_t hook, void *hook_data,
int drive)
{
char name[10];
if (cd_drive && drive == cd_drive)
return hook ("cd", hook_data);
grub_snprintf (name, sizeof (name),
(drive & 0x80) ? "hd%d" : "fd%d", drive & (~0x80));
return hook (name, hook_data);
}
static int
grub_biosdisk_iterate (grub_disk_dev_iterate_hook_t hook, void *hook_data,
grub_disk_pull_t pull)
{
int num_floppies;
int drive;
/* For hard disks, attempt to read the MBR. */
switch (pull)
{
case GRUB_DISK_PULL_NONE:
for (drive = 0x80; drive < 0x90; drive++)
{
if (grub_biosdisk_rw_standard (0x02, drive, 0, 0, 1, 1,
GRUB_MEMORY_MACHINE_SCRATCH_SEG) != 0)
{
grub_dprintf ("disk", "Read error when probing drive 0x%2x\n", drive);
break;
}
if (grub_biosdisk_call_hook (hook, hook_data, drive))
return 1;
}
return 0;
case GRUB_DISK_PULL_REMOVABLE:
if (cd_drive)
{
if (grub_biosdisk_call_hook (hook, hook_data, cd_drive))
return 1;
}
/* For floppy disks, we can get the number safely. */
num_floppies = grub_biosdisk_get_num_floppies ();
for (drive = 0; drive < num_floppies; drive++)
if (grub_biosdisk_call_hook (hook, hook_data, drive))
return 1;
return 0;
default:
return 0;
}
return 0;
}
#pragma pack(1)
typedef struct ventoy_part_table
{
grub_uint8_t Active; // 0x00 0x80
grub_uint8_t StartHead;
grub_uint16_t StartSector : 6;
grub_uint16_t StartCylinder : 10;
grub_uint8_t FsFlag;
grub_uint8_t EndHead;
grub_uint16_t EndSector : 6;
grub_uint16_t EndCylinder : 10;
grub_uint32_t StartSectorId;
grub_uint32_t SectorCount;
}ventoy_part_table;
typedef struct ventoy_mbr_head
{
grub_uint8_t BootCode[446];
ventoy_part_table PartTbl[4];
grub_uint8_t Byte55;
grub_uint8_t ByteAA;
}ventoy_mbr_head;
#pragma pack()
static grub_err_t
grub_biosdisk_rw (int cmd, grub_disk_t disk,
grub_disk_addr_t sector, grub_size_t size,
unsigned segment);
static int ventoy_is_mbr_match(ventoy_mbr_head *head)
{
grub_uint32_t PartStartSector;
if (head->Byte55 != 0x55 || head->ByteAA != 0xAA) {
return 0;
}
if (head->PartTbl[2].SectorCount > 0 || head->PartTbl[3].SectorCount > 0) {
return 0;
}
if (head->PartTbl[0].StartSectorId != 2048) {
return 0;
}
if (head->PartTbl[1].Active != 0x80 || head->PartTbl[1].FsFlag != 0xEF) {
return 0;
}
PartStartSector = head->PartTbl[0].StartSectorId + head->PartTbl[0].SectorCount;
if (head->PartTbl[1].StartSectorId != PartStartSector || head->PartTbl[1].SectorCount != 65536) {
return 0;
}
return 1;
}
static grub_err_t
grub_biosdisk_open (const char *name, grub_disk_t disk)
{
grub_uint64_t total_sectors = 0;
int drive;
struct grub_biosdisk_data *data;
drive = grub_biosdisk_get_drive (name);
if (drive < 0)
return grub_errno;
disk->id = drive;
data = (struct grub_biosdisk_data *) grub_zalloc (sizeof (*data));
if (! data)
return grub_errno;
data->drive = drive;
if ((cd_drive) && (drive == cd_drive))
{
data->flags = GRUB_BIOSDISK_FLAG_LBA | GRUB_BIOSDISK_FLAG_CDROM;
data->sectors = 8;
disk->log_sector_size = 11;
/* TODO: get the correct size. */
total_sectors = GRUB_DISK_SIZE_UNKNOWN;
}
else
{
/* HDD */
int version;
disk->log_sector_size = 9;
version = grub_biosdisk_check_int13_extensions (drive);
if (version)
{
struct grub_biosdisk_drp *drp
= (struct grub_biosdisk_drp *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
/* Clear out the DRP. */
grub_memset (drp, 0, sizeof (*drp));
drp->size = sizeof (*drp);
if (! grub_biosdisk_get_diskinfo_int13_extensions (drive, drp))
{
data->flags = GRUB_BIOSDISK_FLAG_LBA;
if (drp->total_sectors)
total_sectors = drp->total_sectors;
else
/* Some buggy BIOSes doesn't return the total sectors
correctly but returns zero. So if it is zero, compute
it by C/H/S returned by the LBA BIOS call. */
total_sectors = ((grub_uint64_t) drp->cylinders)
* drp->heads * drp->sectors;
if (drp->bytes_per_sector
&& !(drp->bytes_per_sector & (drp->bytes_per_sector - 1))
&& drp->bytes_per_sector >= 512
&& drp->bytes_per_sector <= 16384)
{
for (disk->log_sector_size = 0;
(1 << disk->log_sector_size) < drp->bytes_per_sector;
disk->log_sector_size++);
}
}
}
}
if (! (data->flags & GRUB_BIOSDISK_FLAG_CDROM))
{
if (grub_biosdisk_get_diskinfo_standard (drive,
&data->cylinders,
&data->heads,
&data->sectors) != 0)
{
if (total_sectors && (data->flags & GRUB_BIOSDISK_FLAG_LBA))
{
data->sectors = 63;
data->heads = 255;
data->cylinders
= grub_divmod64 (total_sectors
+ data->heads * data->sectors - 1,
data->heads * data->sectors, 0);
}
else
{
grub_free (data);
return grub_error (GRUB_ERR_BAD_DEVICE, "%s cannot get C/H/S values", disk->name);
}
}
if (data->sectors == 0)
data->sectors = 63;
if (data->heads == 0)
data->heads = 255;
if (! total_sectors)
total_sectors = ((grub_uint64_t) data->cylinders)
* data->heads * data->sectors;
}
disk->total_sectors = total_sectors;
/* Limit the max to 0x7f because of Phoenix EDD. */
disk->max_agglomerate = 0x7f >> GRUB_DISK_CACHE_BITS;
COMPILE_TIME_ASSERT ((0x7f >> GRUB_DISK_CACHE_BITS
<< (GRUB_DISK_SECTOR_BITS + GRUB_DISK_CACHE_BITS))
+ sizeof (struct grub_biosdisk_dap)
< GRUB_MEMORY_MACHINE_SCRATCH_SIZE);
disk->data = data;
//fixup some buggy bios
if (total_sectors > (16434495 - 2097152) && total_sectors < (16434495 + 2097152) &&
(data->flags & GRUB_BIOSDISK_FLAG_LBA) > 0 && (data->flags & GRUB_BIOSDISK_FLAG_CDROM) == 0) {
if (grub_biosdisk_rw(0, disk, 0, 1, GRUB_MEMORY_MACHINE_SCRATCH_SEG) == 0) {
ventoy_mbr_head *mbr = (ventoy_mbr_head *)GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
if (ventoy_is_mbr_match(mbr)) {
total_sectors = mbr->PartTbl[1].StartSectorId + mbr->PartTbl[1].SectorCount + 1;
if (disk->total_sectors < total_sectors) {
disk->total_sectors = total_sectors;
}
}
}
}
return GRUB_ERR_NONE;
}
static void
grub_biosdisk_close (grub_disk_t disk)
{
grub_free (disk->data);
}
/* For readability. */
#define GRUB_BIOSDISK_READ 0
#define GRUB_BIOSDISK_WRITE 1
#define GRUB_BIOSDISK_CDROM_RETRY_COUNT 3
static grub_err_t
grub_biosdisk_rw (int cmd, grub_disk_t disk,
grub_disk_addr_t sector, grub_size_t size,
unsigned segment)
{
struct grub_biosdisk_data *data = disk->data;
/* VirtualBox fails with sectors above 2T on CDs.
Since even BD-ROMS are never that big anyway, return error. */
if ((data->flags & GRUB_BIOSDISK_FLAG_CDROM)
&& (sector >> 32))
return grub_error (GRUB_ERR_OUT_OF_RANGE,
N_("attempt to read or write outside of disk `%s'"),
disk->name);
if (data->flags & GRUB_BIOSDISK_FLAG_LBA)
{
struct grub_biosdisk_dap *dap;
dap = (struct grub_biosdisk_dap *) (GRUB_MEMORY_MACHINE_SCRATCH_ADDR
+ (data->sectors
<< disk->log_sector_size));
dap->length = sizeof (*dap);
dap->reserved = 0;
dap->blocks = size;
dap->buffer = segment << 16; /* The format SEGMENT:ADDRESS. */
dap->block = sector;
if (data->flags & GRUB_BIOSDISK_FLAG_CDROM)
{
int i;
if (cmd)
return grub_error (GRUB_ERR_WRITE_ERROR, N_("cannot write to CD-ROM"));
for (i = 0; i < GRUB_BIOSDISK_CDROM_RETRY_COUNT; i++)
if (! grub_biosdisk_rw_int13_extensions (0x42, data->drive, dap))
break;
if (i == GRUB_BIOSDISK_CDROM_RETRY_COUNT)
return grub_error (GRUB_ERR_READ_ERROR, N_("failure reading sector 0x%llx "
"from `%s'"),
(unsigned long long) sector,
disk->name);
}
else
if (grub_biosdisk_rw_int13_extensions (cmd + 0x42, data->drive, dap))
{
/* Fall back to the CHS mode. */
data->flags &= ~GRUB_BIOSDISK_FLAG_LBA;
disk->total_sectors = data->cylinders * data->heads * data->sectors;
return grub_biosdisk_rw (cmd, disk, sector, size, segment);
}
}
else
{
unsigned coff, hoff, soff;
unsigned head;
/* It is impossible to reach over 8064 MiB (a bit less than LBA24) with
the traditional CHS access. */
if (sector >
1024 /* cylinders */ *
256 /* heads */ *
63 /* spt */)
return grub_error (GRUB_ERR_OUT_OF_RANGE,
N_("attempt to read or write outside of disk `%s'"),
disk->name);
soff = ((grub_uint32_t) sector) % data->sectors + 1;
head = ((grub_uint32_t) sector) / data->sectors;
hoff = head % data->heads;
coff = head / data->heads;
if (coff >= data->cylinders)
return grub_error (GRUB_ERR_OUT_OF_RANGE,
N_("attempt to read or write outside of disk `%s'"),
disk->name);
if (grub_biosdisk_rw_standard (cmd + 0x02, data->drive,
coff, hoff, soff, size, segment))
{
switch (cmd)
{
case GRUB_BIOSDISK_READ:
return grub_error (GRUB_ERR_READ_ERROR, N_("failure reading sector 0x%llx "
"from `%s'"),
(unsigned long long) sector,
disk->name);
case GRUB_BIOSDISK_WRITE:
return grub_error (GRUB_ERR_WRITE_ERROR, N_("failure writing sector 0x%llx "
"to `%s'"),
(unsigned long long) sector,
disk->name);
}
}
}
return GRUB_ERR_NONE;
}
/* Return the number of sectors which can be read safely at a time. */
static grub_size_t
get_safe_sectors (grub_disk_t disk, grub_disk_addr_t sector)
{
grub_size_t size;
grub_uint64_t offset;
struct grub_biosdisk_data *data = disk->data;
grub_uint32_t sectors = data->sectors;
/* OFFSET = SECTOR % SECTORS */
grub_divmod64 (sector, sectors, &offset);
size = sectors - offset;
return size;
}
static grub_err_t
grub_biosdisk_read (grub_disk_t disk, grub_disk_addr_t sector,
grub_size_t size, char *buf)
{
while (size)
{
grub_size_t len;
len = get_safe_sectors (disk, sector);
if (len > size)
len = size;
if (grub_biosdisk_rw (GRUB_BIOSDISK_READ, disk, sector, len,
GRUB_MEMORY_MACHINE_SCRATCH_SEG))
return grub_errno;
grub_memcpy (buf, (void *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR,
len << disk->log_sector_size);
buf += len << disk->log_sector_size;
sector += len;
size -= len;
}
return grub_errno;
}
static grub_err_t
grub_biosdisk_write (grub_disk_t disk, grub_disk_addr_t sector,
grub_size_t size, const char *buf)
{
struct grub_biosdisk_data *data = disk->data;
if (data->flags & GRUB_BIOSDISK_FLAG_CDROM)
return grub_error (GRUB_ERR_IO, N_("cannot write to CD-ROM"));
while (size)
{
grub_size_t len;
len = get_safe_sectors (disk, sector);
if (len > size)
len = size;
grub_memcpy ((void *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR, buf,
len << disk->log_sector_size);
if (grub_biosdisk_rw (GRUB_BIOSDISK_WRITE, disk, sector, len,
GRUB_MEMORY_MACHINE_SCRATCH_SEG))
return grub_errno;
buf += len << disk->log_sector_size;
sector += len;
size -= len;
}
return grub_errno;
}
static struct grub_disk_dev grub_biosdisk_dev =
{
.name = "biosdisk",
.id = GRUB_DISK_DEVICE_BIOSDISK_ID,
.disk_iterate = grub_biosdisk_iterate,
.disk_open = grub_biosdisk_open,
.disk_close = grub_biosdisk_close,
.disk_read = grub_biosdisk_read,
.disk_write = grub_biosdisk_write,
.next = 0
};
static void
grub_disk_biosdisk_fini (void)
{
grub_disk_dev_unregister (&grub_biosdisk_dev);
}
GRUB_MOD_INIT(biosdisk)
{
struct grub_biosdisk_cdrp *cdrp
= (struct grub_biosdisk_cdrp *) GRUB_MEMORY_MACHINE_SCRATCH_ADDR;
grub_uint8_t boot_drive;
if (grub_disk_firmware_is_tainted)
{
grub_puts_ (N_("Native disk drivers are in use. "
"Refusing to use firmware disk interface."));
return;
}
grub_disk_firmware_fini = grub_disk_biosdisk_fini;
grub_memset (cdrp, 0, sizeof (*cdrp));
cdrp->size = sizeof (*cdrp);
cdrp->media_type = 0xFF;
boot_drive = (grub_boot_device >> 24);
if ((! grub_biosdisk_get_cdinfo_int13_extensions (boot_drive, cdrp))
&& ((cdrp->media_type & GRUB_BIOSDISK_CDTYPE_MASK)
== GRUB_BIOSDISK_CDTYPE_NO_EMUL))
cd_drive = cdrp->drive_no;
/* Since diskboot.S rejects devices over 0x90 it must be a CD booted with
cdboot.S
*/
if (boot_drive >= 0x90)
cd_drive = boot_drive;
grub_disk_dev_register (&grub_biosdisk_dev);
}
GRUB_MOD_FINI(biosdisk)
{
grub_disk_biosdisk_fini ();
}
GRUB2/MOD_SRC/grub-2.04/grub-core/disk/loopback.c
+257
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@@ -0,0 +1,257 @@
/* loopback.c - command to add loopback devices. */
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2005,2006,2007 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/file.h>
#include <grub/disk.h>
#include <grub/mm.h>
#include <grub/extcmd.h>
#include <grub/i18n.h>
GRUB_MOD_LICENSE ("GPLv3+");
struct grub_loopback
{
char *devname;
grub_file_t file;
struct grub_loopback *next;
unsigned long id;
grub_off_t skip;
};
static struct grub_loopback *loopback_list;
static unsigned long last_id = 0;
static const struct grub_arg_option options[] =
{
/* TRANSLATORS: The disk is simply removed from the list of available ones,
not wiped, avoid to scare user. */
{"delete", 'd', 0, N_("Delete the specified loopback drive."), 0, 0},
{"skip", 's', 0, "skip sectors of the file.", "SECTORS", ARG_TYPE_INT },
{0, 0, 0, 0, 0, 0}
};
/* Delete the loopback device NAME. */
static grub_err_t
delete_loopback (const char *name)
{
struct grub_loopback *dev;
struct grub_loopback **prev;
/* Search for the device. */
for (dev = loopback_list, prev = &loopback_list;
dev;
prev = &dev->next, dev = dev->next)
if (grub_strcmp (dev->devname, name) == 0)
break;
if (! dev)
return grub_error (GRUB_ERR_BAD_DEVICE, "device not found");
/* Remove the device from the list. */
*prev = dev->next;
grub_free (dev->devname);
grub_file_close (dev->file);
grub_free (dev);
return 0;
}
/* The command to add and remove loopback devices. */
static grub_err_t
grub_cmd_loopback (grub_extcmd_context_t ctxt, int argc, char **args)
{
struct grub_arg_list *state = ctxt->state;
grub_file_t file;
struct grub_loopback *newdev;
grub_err_t ret;
grub_off_t skip = 0;
if (argc < 1)
return grub_error (GRUB_ERR_BAD_ARGUMENT, "device name required");
/* Check if `-d' was used. */
if (state[0].set)
return delete_loopback (args[0]);
if (state[1].set)
skip = (grub_off_t)grub_strtoull(state[1].arg, NULL, 10);
if (argc < 2)
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("filename expected"));
file = grub_file_open (args[1], GRUB_FILE_TYPE_LOOPBACK
| GRUB_FILE_TYPE_NO_DECOMPRESS);
if (! file)
return grub_errno;
/* First try to replace the old device. */
for (newdev = loopback_list; newdev; newdev = newdev->next)
if (grub_strcmp (newdev->devname, args[0]) == 0)
break;
if (newdev)
{
grub_file_close (newdev->file);
newdev->file = file;
newdev->skip = skip;
return 0;
}
/* Unable to replace it, make a new entry. */
newdev = grub_malloc (sizeof (struct grub_loopback));
if (! newdev)
goto fail;
newdev->devname = grub_strdup (args[0]);
if (! newdev->devname)
{
grub_free (newdev);
goto fail;
}
newdev->file = file;
newdev->skip = skip;
newdev->id = last_id++;
/* Add the new entry to the list. */
newdev->next = loopback_list;
loopback_list = newdev;
return 0;
fail:
ret = grub_errno;
grub_file_close (file);
return ret;
}
static int
grub_loopback_iterate (grub_disk_dev_iterate_hook_t hook, void *hook_data,
grub_disk_pull_t pull)
{
struct grub_loopback *d;
if (pull != GRUB_DISK_PULL_NONE)
return 0;
for (d = loopback_list; d; d = d->next)
{
if (hook (d->devname, hook_data))
return 1;
}
return 0;
}
static grub_err_t
grub_loopback_open (const char *name, grub_disk_t disk)
{
struct grub_loopback *dev;
for (dev = loopback_list; dev; dev = dev->next)
if (grub_strcmp (dev->devname, name) == 0)
break;
if (! dev)
return grub_error (GRUB_ERR_UNKNOWN_DEVICE, "can't open device");
/* Use the filesize for the disk size, round up to a complete sector. */
if (dev->file->size != GRUB_FILE_SIZE_UNKNOWN)
disk->total_sectors = ((dev->file->size + GRUB_DISK_SECTOR_SIZE - 1)
/ GRUB_DISK_SECTOR_SIZE);
else
disk->total_sectors = GRUB_DISK_SIZE_UNKNOWN;
/* Avoid reading more than 512M. */
disk->max_agglomerate = 1 << (29 - GRUB_DISK_SECTOR_BITS
- GRUB_DISK_CACHE_BITS);
disk->id = dev->id;
disk->data = dev;
return 0;
}
static grub_err_t
grub_loopback_read (grub_disk_t disk, grub_disk_addr_t sector,
grub_size_t size, char *buf)
{
grub_file_t file = ((struct grub_loopback *) disk->data)->file;
grub_off_t skip = ((struct grub_loopback *) disk->data)->skip;
grub_off_t pos;
grub_file_seek (file, (sector + skip) << GRUB_DISK_SECTOR_BITS);
grub_file_read (file, buf, size << GRUB_DISK_SECTOR_BITS);
if (grub_errno)
return grub_errno;
/* In case there is more data read than there is available, in case
of files that are not a multiple of GRUB_DISK_SECTOR_SIZE, fill
the rest with zeros. */
pos = (sector + skip + size) << GRUB_DISK_SECTOR_BITS;
if (pos > file->size)
{
grub_size_t amount = pos - file->size;
grub_memset (buf + (size << GRUB_DISK_SECTOR_BITS) - amount, 0, amount);
}
return 0;
}
static grub_err_t
grub_loopback_write (grub_disk_t disk __attribute ((unused)),
grub_disk_addr_t sector __attribute ((unused)),
grub_size_t size __attribute ((unused)),
const char *buf __attribute ((unused)))
{
return grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
"loopback write is not supported");
}
static struct grub_disk_dev grub_loopback_dev =
{
.name = "loopback",
.id = GRUB_DISK_DEVICE_LOOPBACK_ID,
.disk_iterate = grub_loopback_iterate,
.disk_open = grub_loopback_open,
.disk_read = grub_loopback_read,
.disk_write = grub_loopback_write,
.next = 0
};
static grub_extcmd_t cmd;
GRUB_MOD_INIT(loopback)
{
cmd = grub_register_extcmd ("loopback", grub_cmd_loopback, 0,
N_("[-d] DEVICENAME FILE."),
/* TRANSLATORS: The file itself is not destroyed
or transformed into drive. */
N_("Make a virtual drive from a file."), options);
grub_disk_dev_register (&grub_loopback_dev);
}
GRUB_MOD_FINI(loopback)
{
grub_unregister_extcmd (cmd);
grub_disk_dev_unregister (&grub_loopback_dev);
}