/**
 * collectd - src/numa.c
 * Copyright (C) 2012       Florian Forster
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 *
 * Authors:
 *   Florian Forster <octo at collectd.org>
 **/

#include "collectd.h"

#include "plugin.h"
#include "utils/common/common.h"

#if !KERNEL_LINUX
#error "No applicable input method."
#endif

#ifndef NUMA_ROOT_DIR
#define NUMA_ROOT_DIR "/sys/devices/system/node"
#endif

static int max_node = -1;

static void numa_dispatch_value(int node, /* {{{ */
                                const char *type_instance, value_t v) {
  value_list_t vl = VALUE_LIST_INIT;

  vl.values = &v;
  vl.values_len = 1;

  sstrncpy(vl.plugin, "numa", sizeof(vl.plugin));
  snprintf(vl.plugin_instance, sizeof(vl.plugin_instance), "node%i", node);
  sstrncpy(vl.type, "vmpage_action", sizeof(vl.type));
  sstrncpy(vl.type_instance, type_instance, sizeof(vl.type_instance));

  plugin_dispatch_values(&vl);
} /* }}} void numa_dispatch_value */

static int numa_read_node(int node) /* {{{ */
{
  char path[PATH_MAX];
  FILE *fh;
  char buffer[128];
  int status;
  int success;

  snprintf(path, sizeof(path), NUMA_ROOT_DIR "/node%i/numastat", node);

  fh = fopen(path, "r");
  if (fh == NULL) {
    ERROR("numa plugin: Reading node %i failed: open(%s): %s", node, path,
          STRERRNO);
    return -1;
  }

  success = 0;
  while (fgets(buffer, sizeof(buffer), fh) != NULL) {
    char *fields[4];
    value_t v;

    status = strsplit(buffer, fields, STATIC_ARRAY_SIZE(fields));
    if (status != 2) {
      WARNING("numa plugin: Ignoring line with unexpected "
              "number of fields (node %i).",
              node);
      continue;
    }

    v.derive = 0;
    status = parse_value(fields[1], &v, DS_TYPE_DERIVE);
    if (status != 0)
      continue;

    numa_dispatch_value(node, fields[0], v);
    success++;
  }

  fclose(fh);
  return success ? 0 : -1;
} /* }}} int numa_read_node */

static int numa_read(void) /* {{{ */
{
  int i;
  int status;
  int success;

  if (max_node < 0) {
    WARNING("numa plugin: No NUMA nodes were detected.");
    return -1;
  }

  success = 0;
  for (i = 0; i <= max_node; i++) {
    status = numa_read_node(i);
    if (status == 0)
      success++;
  }

  return success ? 0 : -1;
} /* }}} int numa_read */

static int numa_init(void) /* {{{ */
{
  /* Determine the number of nodes on this machine. */
  while (42) {
    char path[PATH_MAX];
    struct stat statbuf = {0};
    int status;

    snprintf(path, sizeof(path), NUMA_ROOT_DIR "/node%i", max_node + 1);

    status = stat(path, &statbuf);
    if (status == 0) {
      max_node++;
      continue;
    } else if (errno == ENOENT) {
      break;
    } else /* ((status != 0) && (errno != ENOENT)) */
    {
      ERROR("numa plugin: stat(%s) failed: %s", path, STRERRNO);
      return -1;
    }
  }

  DEBUG("numa plugin: Found %i nodes.", max_node + 1);
  return 0;
} /* }}} int numa_init */

void module_register(void) {
  plugin_register_init("numa", numa_init);
  plugin_register_read("numa", numa_read);
} /* void module_register */