/**
 * collectd - src/zone.c
 * Copyright (C) 2011       Mathijs Mohlmann
 *
 * 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; only version 2 of the License is applicable.
 *
 * 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 St, Fifth Floor, Boston, MA  02110-1301 USA
 *
 * Authors:
 *   Mathijs Mohlmann
 *   Dagobert Michelsen (forward-porting)
 **/

#if HAVE_CONFIG_H
#include "config.h"
#undef HAVE_CONFIG_H
#endif
/* avoid procfs.h error "Cannot use procfs in the large file compilation
 * environment" */
#if !defined(_LP64) && _FILE_OFFSET_BITS == 64
#undef _FILE_OFFSET_BITS
#undef _LARGEFILE64_SOURCE
#endif

#include "collectd.h"

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

#include <procfs.h>
#include <zone.h>

#include "utils/avltree/avltree.h"

#define MAX_PROCFS_PATH 40
#define FRC2PCT(pp) (((float)(pp)) / 0x8000 * 100)

typedef struct zone_stats {
  ushort_t pctcpu;
  ushort_t pctmem;
} zone_stats_t;

static int zone_compare(const void *a, const void *b) {
  if (*(const zoneid_t *)a == *(const zoneid_t *)b)
    return 0;
  if (*(const zoneid_t *)a < *(const zoneid_t *)b)
    return -1;
  return 1;
}

static int zone_read_procfile(char const *pidstr, char const *name, void *buf,
                              size_t bufsize) {
  int fd;

  char procfile[MAX_PROCFS_PATH];
  (void)snprintf(procfile, sizeof(procfile), "/proc/%s/%s", pidstr, name);
  if ((fd = open(procfile, O_RDONLY)) == -1) {
    return 1;
  }

  if (sread(fd, buf, bufsize) != 0) {
    ERROR("zone plugin: Reading \"%s\" failed: %s", procfile, STRERRNO);
    close(fd);
    return 1;
  }

  close(fd);
  return 0;
}

static int zone_submit_value(char *zone, gauge_t value) {
  value_list_t vl = VALUE_LIST_INIT;
  value_t values[1];

  values[0].gauge = value;

  vl.values = values;
  vl.values_len = 1; /*STATIC_ARRAY_SIZE (values);*/
  sstrncpy(vl.plugin, "zone", sizeof(vl.plugin));
  sstrncpy(vl.type, "percent", sizeof(vl.type));
  sstrncpy(vl.type_instance, zone, sizeof(vl.type_instance));

  return plugin_dispatch_values(&vl);
}

static zone_stats_t *zone_find_stats(c_avl_tree_t *tree, zoneid_t zoneid) {
  zone_stats_t *ret = NULL;
  zoneid_t *key = NULL;

  if (c_avl_get(tree, (void **)&zoneid, (void **)&ret)) {
    if (!(ret = malloc(sizeof(*ret)))) {
      WARNING("zone plugin: no memory");
      return NULL;
    }
    if (!(key = malloc(sizeof(*key)))) {
      WARNING("zone plugin: no memory");
      free(ret);
      return NULL;
    }
    *key = zoneid;
    if (c_avl_insert(tree, key, ret)) {
      WARNING("zone plugin: error inserting into tree");
      return NULL;
    }
  }
  return ret;
}

static void zone_submit_values(c_avl_tree_t *tree) {
  char zonename[ZONENAME_MAX];
  zoneid_t *zoneid = NULL;
  zone_stats_t *stats = NULL;

  while (c_avl_pick(tree, (void **)&zoneid, (void **)&stats) == 0) {
    if (getzonenamebyid(*zoneid, zonename, sizeof(zonename)) == -1) {
      WARNING("zone plugin: error retrieving zonename");
    } else {
      zone_submit_value(zonename, (gauge_t)FRC2PCT(stats->pctcpu));
    }
    free(stats);
    free(zoneid);
  }
  c_avl_destroy(tree);
}

static c_avl_tree_t *zone_scandir(DIR *procdir) {
  pid_t pid;
  dirent_t *direntp;
  psinfo_t psinfo;
  c_avl_tree_t *tree;
  zone_stats_t *stats;

  if (!(tree = c_avl_create(zone_compare))) {
    WARNING("zone plugin: Failed to create tree");
    return NULL;
  }

  rewinddir(procdir);
  while ((direntp = readdir(procdir))) {
    char const *pidstr = direntp->d_name;
    if (pidstr[0] == '.') /* skip "." and ".."  */
      continue;

    pid = atoi(pidstr);
    if (pid == 0 || pid == 2 || pid == 3)
      continue; /* skip sched, pageout and fsflush */

    if (zone_read_procfile(pidstr, "psinfo", &psinfo, sizeof(psinfo_t)) != 0)
      continue;

    stats = zone_find_stats(tree, psinfo.pr_zoneid);
    if (stats) {
      stats->pctcpu += psinfo.pr_pctcpu;
      stats->pctmem += psinfo.pr_pctmem;
    }
  }
  return tree;
}

static int zone_read(void) {
  DIR *procdir;
  c_avl_tree_t *tree;

  if ((procdir = opendir("/proc")) == NULL) {
    ERROR("zone plugin: cannot open /proc directory\n");
    return -1;
  }

  tree = zone_scandir(procdir);
  closedir(procdir);
  if (tree == NULL) {
    return -1;
  }
  zone_submit_values(tree); /* this also frees tree */
  return 0;
}

void module_register(void) {
  plugin_register_read("zone", zone_read);
} /* void module_register */