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/*
* Copyright (C) 2012 Davidlohr Bueso <dave@gnu.org>
*
* This program 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 2 of the License, or
* (at your option) any later version.
*
* This program 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 this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include <errno.h>
#include <string.h>
#include <stdlib.h>
#include <unistd.h>
#ifdef HAVE_LIBBLKID
#include <blkid.h>
#endif

#include "nls.h"
#include "blkdev.h"
#include "common.h"
#include "fdisk.h"

int fdisk_debug_mask;

/*
* label probing functions
*/
static const struct fdisk_label *labels[] =
{
&bsd_label,
&dos_label,
&sgi_label,
&sun_label,
&aix_label,
&mac_label,
};

static int __probe_labels(struct fdisk_context *cxt)
{
int i, rc = 0;

disklabel = ANY_LABEL;
update_units(cxt);

for (i = 0; i < ARRAY_SIZE(labels); i++) {
rc = labels[i]->probe(cxt);
if (rc) {
DBG(LABEL, dbgprint("detected a %s label\n",
labels[i]->name));
goto done;
}
}

done:
return rc;
}

static int __init_mbr_buffer(struct fdisk_context *cxt)
{
DBG(TOPOLOGY, dbgprint("initialize MBR buffer"));

cxt->mbr = calloc(1, MAX_SECTOR_SIZE);
if (!cxt->mbr)
goto fail;

/* read MBR */
if (512 != read(cxt->dev_fd, cxt->mbr, 512))
goto fail;

return 0;
fail:
return -1;
}

static unsigned long __get_sector_size(int fd)
{
int sect_sz;

if (!blkdev_get_sector_size(fd, &sect_sz))
return (unsigned long) sect_sz;
return DEFAULT_SECTOR_SIZE;
}

/**
* fdisk_geom_set_cyls
* @cxt: fdisk context
*
* Sets the cylinders based on sectors and heads
*/
void fdisk_geom_set_cyls(struct fdisk_context *cxt)
{
cxt->geom.cylinders = cxt->total_sectors /
(cxt->geom.heads * cxt->geom.sectors);
}

static int __discover_geometry(struct fdisk_context *cxt)
{
sector_t nsects;
unsigned int h = 0, s = 0;

/* get number of 512-byte sectors, and convert it the real sectors */
if (!blkdev_get_sectors(cxt->dev_fd, &nsects))
cxt->total_sectors = (nsects / (cxt->sector_size >> 9));

get_partition_table_geometry(cxt, &h, &s);
if (h && s)
goto hs_ok;

/* what the kernel/bios thinks the geometry is */
blkdev_get_geometry(cxt->dev_fd, &h, &s);
if (h && s)
goto hs_ok;

/* unable to discover geometry, use default values */
s = 63;
h = 255;

hs_ok: /* obtained heads and sectors */
cxt->geom.heads = h;
cxt->geom.sectors = s;
fdisk_geom_set_cyls(cxt);
update_sector_offset(cxt);

DBG(GEOMETRY, dbgprint("geometry discovered for %s: C/H/S: %lld/%d/%lld",
cxt->dev_path, cxt->geom.cylinders,
cxt->geom.heads, cxt->geom.sectors));

return 0;
}

static int __discover_topology(struct fdisk_context *cxt)
{
#ifdef HAVE_LIBBLKID
blkid_probe pr;

DBG(TOPOLOGY, dbgprint("initialize libblkid prober"));

pr = blkid_new_probe();
if (pr && blkid_probe_set_device(pr, cxt->dev_fd, 0, 0) == 0) {
blkid_topology tp = blkid_probe_get_topology(pr);

if (tp) {
cxt->min_io_size = blkid_topology_get_minimum_io_size(tp);
cxt->optimal_io_size = blkid_topology_get_optimal_io_size(tp);
cxt->phy_sector_size = blkid_topology_get_physical_sector_size(tp);
cxt->alignment_offset = blkid_topology_get_alignment_offset(tp);

/* I/O size used by fdisk */
cxt->io_size = cxt->optimal_io_size;
if (!cxt->io_size)
/* optimal IO is optional, default to minimum IO */
cxt->io_size = cxt->min_io_size;
}
}
blkid_free_probe(pr);
#endif

/* no blkid or error, use default values */
if (!cxt->min_io_size)
cxt->min_io_size = DEFAULT_SECTOR_SIZE;
if (!cxt->io_size)
cxt->io_size = DEFAULT_SECTOR_SIZE;

cxt->sector_size = __get_sector_size(cxt->dev_fd);
if (!cxt->phy_sector_size) /* could not discover physical size */
cxt->phy_sector_size = cxt->sector_size;

DBG(TOPOLOGY, dbgprint("topology discovered for %s:\n"
"\tlogical/physical sector sizes: %ld/%ld\n"
"\tfdisk/minimal/optimal io sizes: %ld/%ld/%ld\n",
cxt->dev_path, cxt->sector_size, cxt->phy_sector_size,
cxt->io_size, cxt->optimal_io_size, cxt->min_io_size));
return 0;
}

/**
* fdisk_mbr_zeroize:
* @cxt: fdisk context
*
* Zero's MBR buffer
*/
void fdisk_mbr_zeroize(struct fdisk_context *cxt)
{
if (cxt->mbr) {
DBG(CONTEXT, dbgprint("zeroize in-memory MBR"));
memset(cxt->mbr, 0, MAX_SECTOR_SIZE);
}
}

/**
* fdisk_dev_sectsz_is_default:
* @cxt: fdisk context
*
* Returns 1 if the device's sector size is the default value, otherwise 0.
*/
int fdisk_dev_sectsz_is_default(struct fdisk_context *cxt)
{
return cxt->sector_size == DEFAULT_SECTOR_SIZE;
}

/**
* fdisk_dev_has_topology:
* @cxt: fdisk context
*
* Returns 1 if the device provides topology information, otherwise 0.
*/
int fdisk_dev_has_topology(struct fdisk_context *cxt)
{
/*
* Assume that the device provides topology info if
* optimal_io_size is set or alignment_offset is set or
* minimum_io_size is not power of 2.
*/
if (cxt->optimal_io_size || cxt->alignment_offset ||
!is_power_of_2(cxt->min_io_size))
return 1;
return 0;
}

/**
* fdisk_init_debug:
* @mask: debug mask (0xffff to enable full debuging)
*
* If the @mask is not specified then this function reads
* FDISK_DEBUG environment variable to get the mask.
*
* Already initialized debugging stuff cannot be changed. It does not
* have effect to call this function twice.
*/
void fdisk_init_debug(int mask)
{
if (fdisk_debug_mask & FDISK_DEBUG_INIT)
return;
if (!mask) {
char *str = getenv("FDISK_DEBUG");
if (str)
fdisk_debug_mask = strtoul(str, 0, 0);
} else
fdisk_debug_mask = mask;

if (fdisk_debug_mask)
fprintf(stderr, "fdisk: debug mask set to 0x%04x.\n",
fdisk_debug_mask);
fdisk_debug_mask |= FDISK_DEBUG_INIT;
}

/**
* fdisk_new_context:
* @filename: path to the device to be handled
* @readonly: how to open the device
*
* If the @readonly flag is set to false, fdisk will attempt to open
* the device with read-write mode and will fallback to read-only if
* unsuccessful.
*
* Returns: newly allocated fdisk context
*/
struct fdisk_context *fdisk_new_context_from_filename(const char *fname, int readonly)
{
int fd, errsv = 0;
struct fdisk_context *cxt = NULL;

DBG(CONTEXT, dbgprint("initializing context for %s", fname));

if (readonly == 1 || (fd = open(fname, O_RDWR)) < 0) {
if ((fd = open(fname, O_RDONLY)) < 0)
return NULL;
readonly = 1;
}

cxt = calloc(1, sizeof(*cxt));
if (!cxt)
goto fail;

cxt->dev_fd = fd;
cxt->dev_path = strdup(fname);
if (!cxt->dev_path)
goto fail;

if (__init_mbr_buffer(cxt) < 0)
goto fail;

__discover_topology(cxt);
__discover_geometry(cxt);

__probe_labels(cxt);

DBG(CONTEXT, dbgprint("context initialized for %s [%s]",
fname, readonly ? "READ-ONLY" : "READ-WRITE"));
return cxt;
fail:
errsv = errno;
fdisk_free_context(cxt);
errno = errsv;

DBG(CONTEXT, dbgprint("failed to initialize context for %s: %m", fname));
return NULL;
}

/**
* fdisk_free_context:
* @cxt: fdisk context
*
* Deallocates context struct.
*/
void fdisk_free_context(struct fdisk_context *cxt)
{
if (!cxt)
return;

DBG(CONTEXT, dbgprint("freeing context for %s", cxt->dev_path));
close(cxt->dev_fd);
free(cxt->dev_path);
free(cxt->mbr);
free(cxt);
}
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