#include <config.h>
#include <glibtop.h>
#include <glibtop/fsusage.h>
#include <glibtop/error.h>

#include "glibtop_private.h"

#include <glib.h>

#include <unistd.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <linux/kdev_t.h>
#include <sys/statvfs.h>
#include <stdio.h>
#include <string.h>
#include <stdlib.h>
#include <errno.h>
#include <mntent.h>


/*
 * Linux 2.6.x
 * linux/Documentation/iostats.txt
 */




static gboolean
get_device(glibtop* server, const char *mountpoint,
	   char* device, size_t device_size)
{
	const struct mntent *mnt;
	FILE *fp;
	gboolean found = FALSE;

	if (!(fp = setmntent(MOUNTED, "r"))) {
		glibtop_warn_io_r(server, "Could not open %s", MOUNTED);
		goto out;
	}

	while ((mnt = getmntent(fp)))
	{
		/* There can be multiple root mount entries, skip the unuseful one */
		if (!strcmp(mnt->mnt_fsname, "rootfs"))
			continue;

		if (!strcmp(mountpoint, mnt->mnt_dir)) {
			if (!strncmp(mnt->mnt_fsname, "/dev/", 5)) {
				g_strlcpy(device, mnt->mnt_fsname + 5, device_size);
				found = TRUE;
			}
			break;
		}
	}

	endmntent(fp);
out:
	return found;
}


/*
  TRUE if device is like "hda3" and then set prefix to "hda".
 */
static gboolean
is_partition(const char* device, char* prefix, size_t prefix_size)
{
	g_strlcpy(prefix, device, prefix_size);

	for ( ; *prefix; prefix++) {
		if (isdigit(*prefix)) {
			*prefix = '\0';
			return TRUE;
		}
	}

	return FALSE;
}


/*
  Bug #539360.
  /sys/.../stat format is partially defined in
  linux/Documentation/block/stat.txt (looks outdated).  Before linux
  2.5.25, /sys/block/%s/stat and /sys/block/%s/%s/stat were not the
  same, but the following commit changed the latter to have the same
  format and broke compatibility.

  Commit 34e8beac92c27d292938065f8375842d2840767c
  Author: Jerome Marchand <jmarchan@redhat.com>
  Date:   Fri Feb 8 11:04:55 2008 +0100

    Enhanced partition statistics: sysfs

    Reports enhanced partition statistics in sysfs.

    Signed-off-by: Jerome Marchand <jmarchan@redhat.com>

    fs/partitions/check.c |   22 +++++++++++++++++++---
    1 files changed, 19 insertions(+), 3 deletions(-)

 */

static void
get_sys_path(glibtop* server, const char *device, char **stat_path, const char **parse_format)
{
	const char* linux_2_6_25_format = "%*llu %*llu %llu %*llu"
					  "%*llu %*llu %llu %*llu";

	char prefix[32];

	if (is_partition(device, prefix, sizeof prefix)) {

		*stat_path = g_strdup_printf("/sys/block/%s/%s/stat",
					     prefix, device);
		if (server->os_version_code < LINUX_VERSION_CODE(2, 6, 25))
			*parse_format = "%*llu %llu %*llu %llu";
		else
			*parse_format = linux_2_6_25_format;
	}
	else
	{
		*stat_path = g_strdup_printf("/sys/block/%s/stat", device);
		if (server->os_version_code < LINUX_VERSION_CODE(2, 6, 25))
			*parse_format = "%*llu %*llu %llu %*llu %*llu %*llu %llu";
		else
			*parse_format = linux_2_6_25_format;
	}
}



static void linux_2_6_0(glibtop *server, glibtop_fsusage *buf, const char *path)
{
	char *filename = NULL;
	const char *format;
	int ret;
	char buffer[BUFSIZ];
	char device[64];

	if (!get_device(server, path, device, sizeof device))
		goto out;

	get_sys_path(server, device, &filename, &format);

	ret = try_file_to_buffer(buffer, sizeof buffer, "%s", filename);

	if (ret < 0) goto out;

	if (sscanf(buffer, format, &buf->read, &buf->write) != 2) {
		glibtop_warn_io_r(server, "Could not parse %s", filename);
		goto out;
	}

	buf->flags |= (1 << GLIBTOP_FSUSAGE_READ) | (1 << GLIBTOP_FSUSAGE_WRITE);
 out:
	g_free(filename);
}


static void linux_2_4_0(glibtop *server, glibtop_fsusage *buf, const char *path)
{
}


static void
get_fsusage_read_write(glibtop *server, glibtop_fsusage *buf, const char *path)
{
  if(server->os_version_code >= LINUX_VERSION_CODE(2, 6, 0))
    {
      linux_2_6_0(server, buf, path);
    }
  else if(server->os_version_code >= LINUX_VERSION_CODE(2, 4, 0))
    {
      linux_2_4_0(server, buf, path);
    }
}


/* the following comes from sysdeps/common/mountlist.c if copyright matters...
 */

static const unsigned long _glibtop_sysdeps_fsusage =
(1L << GLIBTOP_FSUSAGE_BLOCKS) + (1L << GLIBTOP_FSUSAGE_BFREE)
+ (1L << GLIBTOP_FSUSAGE_BAVAIL) + (1L << GLIBTOP_FSUSAGE_FILES)
+ (1L << GLIBTOP_FSUSAGE_FFREE) + (1L << GLIBTOP_FSUSAGE_BLOCK_SIZE);



void
glibtop_get_fsusage_s(glibtop *server, glibtop_fsusage *buf, const char *path)
{
  struct statvfs fsd;

  memset(buf, 0, sizeof(glibtop_fsusage));

  if (statvfs(path, &fsd) < 0) {
    glibtop_warn_r(server, "statvfs '%s' failed: %s", path, strerror (errno));
    return;
  }

  buf->blocks = fsd.f_blocks;
  buf->bfree  = fsd.f_bfree;
  buf->bavail = (fsd.f_bavail > fsd.f_bfree) ? 0 : fsd.f_bavail;
  buf->files  = fsd.f_files;
  buf->ffree  = fsd.f_ffree;
  buf->block_size = fsd.f_bsize;
  buf->flags = _glibtop_sysdeps_fsusage;

  /* setting additional flags is delegated */
  get_fsusage_read_write(server, buf, path);
}