/* virt-hostinfo
 * Copyright (C) 2009 Red Hat Inc.
 *
 * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <fnmatch.h>

#include <apr_general.h>
#include <apr_strings.h>

#include "hostinfod.h"

typedef int (*process_line_fn) (const char *path, int lineno,
				const char *key, const char *value,
				void *data);
typedef int (*process_section_fn) (const char *path, int lineno,
				   const char *section,
				   void *data);
static void process_conf_file (const char *path, int exit_if_not_exist,
			       process_line_fn process_line,
			       process_section_fn process_section,
			       void *data);
static int get_bool (const char *str);

/* Read the main configuration file. */
static int main_process_line (const char *path, int lineno, const char *key, const char *value, void *data);

void
read_main_conf_file (void)
{
  process_conf_file (conf_file, 0, main_process_line, NULL, NULL);
}

static int
main_process_line (const char *path, int lineno,
		   const char *key, const char *value,
		   void *data)
{
  int bool;

  if (strcasecmp (key, "guests") == 0) {
    if (!value) {
      error ("%s:%d: directive is empty: %s", path, lineno, key);
      return -1;
    }
    guests_file = apr_pstrdup (pool, value);
  } else if (strcasecmp (key, "sockets") == 0) {
    if (!value) {
      error ("%s:%d: directive is empty: %s", path, lineno, key);
      return -1;
    }
    socket_dir = apr_pstrdup (pool, value);
  } else if (strcasecmp (key, "libvirt") == 0) {
    if (!value) {
      error ("%s:%d: directive is empty: %s", path, lineno, key);
      return -1;
    }
    if (!libvirt_uri_set_on_cmdline)
      libvirt_uri = apr_pstrdup (pool, value);
  } else if (strcasecmp (key, "verbose") == 0) {
    bool = get_bool (value);
    if (bool == -1) {
      error ("%s:%d: %s: not a valid boolean - use 1 or 0", path, lineno, key);
      return -1;
    }
    if (!verbose_set_on_cmdline)
      verbose = bool;
  } else if (strcasecmp (key, "foreground") == 0) {
    bool = get_bool (value);
    if (bool == -1) {
      error ("%s:%d: %s: not a valid boolean - use 1 or 0", path, lineno, key);
      return -1;
    }
    if (!foreground_set_on_cmdline)
      foreground = bool;
  } else {
    error ("%s:%d: unknown directive in configuration file: %s",
	   path, lineno, key);
    return -1;
  }
  return 0;
}

/* Check that 'cmd' is enabled for the named guest, and that
 * it is not being called too frequently.
 *
 * XXX Rereading the configuration file each time is possibly
 * inefficient.
 *
 * Returns 0 = proceed, -1 = fail.
 */
static int guests_process_line (const char *path, int lineno,
				const char *key, const char *value,
				void *data);
static int guests_process_section (const char *path, int lineno,
				   const char *section,
				   void *data);

struct guests_data {
  const char *name;		/* guest "driver-name" */
  const char *cmd;		/* command being tested */
  int in_section;		/* currently processing the right section? */
  double interval;		/* interval for this guest (0 = any) */
  int interval_set;		/* have we set interval yet? */
  int enabled;			/* is command enabled? */
  int enabled_set;		/* have we set enabled flag yet? */
};

void
check_guests_file (struct guest_description *hval, const char *cmd,
		   double *interval, int *enabled)
{
  struct guests_data *data = apr_palloc (hval->rpool, sizeof *data);

  data->name = hval->name;
  data->cmd = cmd;
  data->in_section = 0;
  data->interval = 60.;		/* default */
  data->interval_set = 0;
  data->enabled = 0;		/* default */
  data->enabled_set = 0;

  process_conf_file (guests_file, 1,
		     guests_process_line, guests_process_section, data);

  *interval = data->interval;
  *enabled = data->enabled;
}

static int
guests_process_line (const char *path, int lineno,
		     const char *key, const char *value,
		     void *datav)
{
  struct guests_data *data = datav;
  int bool;

  if (!data->in_section)
    return 0;

  if (strcasecmp (key, "interval") == 0) {
    if (!data->interval_set) {
      if (strcasecmp (value, "any") == 0)
	data->interval = 0;
      else {
	if (sscanf (value, "%lg", &data->interval) != 1) {
	  error ("%s:%d: %s: not a valid decimal number", path, lineno, key);
	  return -1;
	}
      }
      data->interval_set = 1;
    }
  } else if (strcasecmp (key, data->cmd) == 0) {
    if (!data->enabled_set) {
      bool = get_bool (value);
      if (bool == -1) {
	error ("%s:%d: %s: not a valid boolean - use 1 or 0", path, lineno, key);
	return -1;
      }
      data->enabled = bool;
      data->enabled_set = 1;
    }
  }

  return 0;
}

static int
guests_process_section (const char *path, int lineno,
			const char *section,
			void *datav)
{
  struct guests_data *data = datav;
  int flags = 0;

#ifdef FNM_CASEFOLD
  flags |= FNM_CASEFOLD;
#endif

  data->in_section = fnmatch (section, data->name, flags) == 0;
  return 0;
}

/* Configuration file parser. */
static void
process_conf_file (const char *path, int exit_if_not_exist,
		   process_line_fn process_line,
		   process_section_fn process_section,
		   void *data)
{
  static const char *whitespace = " \t\n\v";
  FILE *fp;
  char *line = NULL;
  int lineno = 0;
  size_t len = 0;
  size_t real_len, key_len;
  ssize_t r;
  const char *key, *value;

  debug ("begin processing configuration file %s", path);

  fp = fopen (path, "r");
  if (!fp) {
    if (exit_if_not_exist) {
      perrorf ("%s", path);
      exit (1);
    } else
      pwarningf ("%s", path);
    return;
  }

  while ((r = getline (&line, &len, fp)) != -1) {
    lineno++;

    /*debug ("%s:%d: '%s' (len = %d)", path, lineno, line, len);*/

    /* Remove trailing \n */
    real_len = strlen (line);
    if (real_len > 0 && line[real_len-1] == '\n')
      line[--real_len] = '\0';

    /* Ignore blank lines and comments. */
    if (real_len == 0)
      continue;
    if (line[0] == '#' || strspn (line, whitespace) == real_len)
      continue;

    if (line[0] == '[') {	/* Section. */
      if (line[real_len-1] == ']')
	line[--real_len] = '\0';
      else {
	error ("%s:%d: in section header, ']' not found (is there trailing whitespace or a comment?), near: %s",
	       path, lineno, line);
	exit (1);
      }

      debug ("configuration file: section [%s]", &line[1]);

      if (!process_section) {
	error ("%s:%d: unexpected section header ([%s]) in file",
	       path, lineno, &line[1]);
	exit (1);
      }

      if (process_section (path, lineno, &line[1], data) == -1)
	exit (1);
    }
    else {			/* Key value */
      key_len = strcspn (line, whitespace);
      line[key_len] = '\0';
      key = line;
      value = key_len < real_len ? &line[key_len+1] : NULL;
      if (value) {
	value += strspn (value, whitespace);
	if (value[0] == '\0')
	  value = NULL;
      }

      debug ("configuration file: key '%s', value '%s'", key, value);

      if (process_line && process_line (path, lineno, key, value, data) == -1)
	exit (1);
    }
  }

  free (line);

  if (ferror (fp)) {
    error ("%s: error reading configuration file", path);
    exit (1);
  }
  if (fclose (fp) == EOF) {
    perrorf ("%s", path);
    exit (1);
  }

  debug ("finished processing configuration file successfully");
}

static int
get_bool (const char *str)
{
  if (!str)
    return -1;

  if (strcasecmp (str, "on") == 0)
    return 1;
  if (strcasecmp (str, "off") == 0)
    return 0;

  switch (str[0]) {
  case '1': case 'y': case 'Y': case 't': case 'T': case 'e': case 'E':
    return 1;
  case '0': case 'n': case 'N': case 'f': case 'F': case 'd': case 'D':
    return 0;
  }

  return -1;
}