#include "config.h"

#include "plugin.h"

#include "common/soa.h"
#include "common/strset.h"

#include <stdarg.h>
#include <string.h>
#include <stdio.h>
#include <assert.h>
#include <stdlib.h>
#include <errno.h>
#include <unistd.h>

/*----------------------------------------------------------------------------------
 * DECLARATIONS
 */

static const char *dnsserial_soa_attribute = "sOARecord";
static const char *dnsserial_soa_base = "";

static Slapi_Mutex *dnsserial_mutex = NULL;
static strset *dnsserial_soa_cache = NULL;
static int dnsserial_enable = 0;

/* ---------------------------------------------------------------------------------
 * MEMORY ALLOCATION
 */

void*
strset_malloc (size_t length)
{
	return slapi_ch_malloc (length);
}

void
strset_free (void *ptr)
{
	return slapi_ch_free (&ptr);
}

/* ---------------------------------------------------------------------------------
 * LDAP OPERATIONS
 */

static int
search_for_dns (const char *base, const char *filter, char ***results)
{
	Slapi_Entry **entries, **e;
	Slapi_PBlock *pb;
	LDAPControl *ctrl;
	char **dns, **d;
	char *attr, *dn;
	int rc, num, code;

	assert (results);
	assert (filter && filter[0]);
	assert (base && base[0]);

	ctrl = NULL; /* No controls */
	attr = NULL; /* No attributes */

	trace ("performing internal search");

	/* Do the actual search */
	pb = slapi_search_internal ((char*)base, LDAP_SCOPE_SUBTREE, (char*)filter, &ctrl, &attr, 1);
	return_val_if_fail (pb, -1);

	/* Was it successful? */
	code = -1;
	rc = slapi_pblock_get (pb, SLAPI_PLUGIN_INTOP_RESULT, &code);
	return_val_if_fail (rc >= 0, -1);
	if (code != LDAP_SUCCESS) {
		log_plugin ("error performing search on %s for %s (code %d)", base, filter, code);
		slapi_pblock_destroy (pb);
		trace ("failure");
		return -1;
	}

	/* Dig out all the entries */
	entries = NULL;
	rc = slapi_pblock_get (pb, SLAPI_PLUGIN_INTOP_SEARCH_ENTRIES, &entries);
	return_val_if_fail (rc >= 0, -1);

	/* How many entries? */
	num = 0;
	for (e = entries; entries && *e; ++e)
		++num;

	/* Allocate memory and copy over all dns found */
	d = dns = (char**)slapi_ch_calloc (num + 1, sizeof (char*));
	for (e = entries; entries && *e; ++e) {
		dn = slapi_entry_get_dn (*e);
		return_val_if_fail (dn, -1);

		dn = slapi_ch_strdup (dn);
		dn = slapi_dn_normalize_case (dn);
		*(d++) = dn;
	}

	slapi_pblock_destroy (pb);
	*results = dns;

	trace ("success");
	return 0;
}

static int
populate_soa_cache (void)
{
	char **dns, **d;
	char *filter;
	int rc, len, have;

	assert (dnsserial_mutex);

	have = 0;
	slapi_lock_mutex (dnsserial_mutex);

		/* Already populated? */
		have = dnsserial_soa_cache ? 1 : 0;

	slapi_unlock_mutex (dnsserial_mutex);

	if (have)
		return 1;

	/* Build up the filter */
	len = strlen (dnsserial_soa_attribute) +
	      strlen ("(%s=*)");
	filter = slapi_ch_malloc (len);
	strcpy (filter, "(");
	strcat (filter, dnsserial_soa_attribute);
	strcat (filter, "=*)");

	trace (filter);

	rc = search_for_dns (dnsserial_soa_base, filter, &dns);
	slapi_ch_free_string (&filter);

	if (rc < 0)
		return rc;

	/* Normalize all the DNs */
	for (d = dns; *d; ++d)
		slapi_dn_normalize_case (*d);

	/* Now we're ready to put them in the cache */
	assert (dnsserial_mutex);
	slapi_lock_mutex (dnsserial_mutex);

		/* Already populated? */
		if (!dnsserial_soa_cache) {
			dnsserial_soa_cache = strset_create ();
			for (d = dns; *d; ++d)
				strset_add (dnsserial_soa_cache, *d);
		}

	slapi_unlock_mutex (dnsserial_mutex);

	slapi_ch_array_free (dns);
	return 1;
}

static int
present_in_soa_cache (const char *dn)
{
	int present;

	assert (dn && dn[0]);
	assert (dnsserial_mutex);

	if (populate_soa_cache () < 0)
		return 0;

	slapi_lock_mutex (dnsserial_mutex);

		present = strset_has (dnsserial_soa_cache, dn);

	slapi_unlock_mutex (dnsserial_mutex);

	return present;
}

static char*
ancestor_in_soa_cache (const char *dn)
{
	Slapi_DN *sdn = NULL;
	Slapi_DN *parent = NULL;
	char *ancestor;

	assert (dn && dn[0]);
	assert (dnsserial_mutex);

	if (populate_soa_cache () < 0)
		return 0;

	sdn = slapi_sdn_new_dn_byval (dn);
	return_val_if_fail (sdn, 0);

	ancestor = NULL;
	slapi_lock_mutex (dnsserial_mutex);

		for (;;) {

			/* Get the parent of the dn */
			assert (sdn);
			assert (!parent);
			parent = slapi_sdn_new ();
			slapi_sdn_get_parent (sdn, parent);

			/* Reached the root? */
			if (slapi_sdn_isempty (parent))
				break;

			/* Reached the top of our SOA block? */
			dn = slapi_sdn_get_dn (parent);
			if (strcmp (dn, dnsserial_soa_base) == 0)
				break;

			/* Found this DN? */
			if (strset_has (dnsserial_soa_cache, dn)) {
				ancestor = slapi_ch_strdup (dn);
				break;
			}

			slapi_sdn_free (&sdn);
			sdn = parent;
			parent = NULL;
		}


	slapi_unlock_mutex (dnsserial_mutex);

	if (sdn)
		slapi_sdn_free (&sdn);
	if (parent)
		slapi_sdn_free (&parent);

	return ancestor;
}

static int
add_to_soa_cache (const char *dn)
{
	assert (dn && dn[0]);
	assert (dnsserial_mutex);

	if (populate_soa_cache () < 0)
		return -1;

	slapi_lock_mutex (dnsserial_mutex);

		strset_add (dnsserial_soa_cache, dn);

	slapi_unlock_mutex (dnsserial_mutex);

	return 0;
}

static int
remove_from_soa_cache (const char *dn)
{
	assert (dn && dn[0]);

	if (populate_soa_cache () < 0)
		return -1;

	slapi_lock_mutex (dnsserial_mutex);

		strset_remove (dnsserial_soa_cache, dn);

	slapi_unlock_mutex (dnsserial_mutex);

	return 0;
}

static char*
load_soa_attribute (const char *dn)
{
	Slapi_Entry **entries;
	struct berval **values;
	Slapi_PBlock *pb;
	Slapi_Attr *attr;
	LDAPControl *ctrl;
	char *attrs[2];
	char *soa;
	int rc, code;

	trace (dn);
	assert (dn && dn[0]);
	assert (dnsserial_soa_attribute);

	ctrl = NULL; /* No controls */
	attrs[0] = (char*)dnsserial_soa_attribute;
	attrs[1] = NULL;

	trace ("performing internal search");

	/* Do the actual search */
	pb = slapi_search_internal ((char*)dn, LDAP_SCOPE_BASE, "(objectClass=*)", &ctrl, attrs, 0);
	return_val_if_fail (pb, NULL);

	/* Was it successful? */
	code = -1;
	rc = slapi_pblock_get (pb, SLAPI_PLUGIN_INTOP_RESULT, &code);
	return_val_if_fail (rc >= 0, NULL);
	if (code != LDAP_SUCCESS) {
		log_plugin ("error loading attribute %s from %s (code %d)", dnsserial_soa_attribute, dn, code);
		slapi_pblock_destroy (pb);
		trace ("failure");
		return NULL;
	}

	/* Dig out all the entries */
	entries = NULL;
	slapi_pblock_get (pb, SLAPI_PLUGIN_INTOP_SEARCH_ENTRIES, &entries);
	return_val_if_fail (entries, NULL);

	soa = NULL;
	if (entries[0]) {
		if (slapi_entry_attr_find (entries[0], (char*)dnsserial_soa_attribute, &attr) >= 0 && attr &&
		    slapi_attr_get_values (attr, &values) >= 0 && values && values[0]) {

			/* Convert the berval into a string */
			soa = slapi_ch_malloc (values[0]->bv_len + 1);
			if (values[0]->bv_len)
				memcpy (soa, values[0]->bv_val, values[0]->bv_len);
			soa[values[0]->bv_len] = 0;
		}
	}

	slapi_pblock_destroy (pb);
	trace ("success");

	return soa;
}

static int
change_soa_attribute (const char *dn, const char *soa_old, const char *soa_new)
{
	Slapi_PBlock *pb;
	LDAPMod *mods[3];
	char *values_add[2];
	char *values_remove[2];
	LDAPMod mod_add;
	LDAPMod mod_remove;
	int rc, code;

	trace (dn);

	assert (dn && dn[0]);
	assert (soa_old);
	assert (soa_new);

	/* Setup the mods to change */
	values_add[0] = (char*)soa_new;
	values_add[1] = NULL;
	mod_add.mod_op = LDAP_MOD_ADD;
	mod_add.mod_type = (char*)dnsserial_soa_attribute;
	mod_add.mod_values = values_add;

	values_remove[0] = (char*)soa_old;
	values_remove[1] = NULL;
	mod_remove.mod_op = LDAP_MOD_DELETE;
	mod_remove.mod_type = (char*)dnsserial_soa_attribute;
	mod_remove.mod_values = values_remove;

	mods[0] = &mod_remove;
	mods[1] = &mod_add;
	mods[2] = NULL;

	trace ("performing modify internal");

	pb = slapi_modify_internal ((char*)dn, mods, NULL, 1);
	return_val_if_fail (pb, -1);

	code = -1;
	rc = slapi_pblock_get (pb, SLAPI_PLUGIN_INTOP_RESULT, &code);
	return_val_if_fail (pb, -1);
	slapi_pblock_destroy (pb);

	if (code != LDAP_SUCCESS && code != LDAP_TYPE_OR_VALUE_EXISTS && code != LDAP_NO_SUCH_ATTRIBUTE) {
		log_plugin ("couldn't replace %s on %s with '%s' (code %d)",
		            dnsserial_soa_attribute, dn, soa_new, code);
		trace ("failure");
		return -1;
	}

	/* Call the dns notify code, and note that we've changed a sOARecord */
	dnsnotify_post_modify (dn, mods);

	trace ("success");
	return 0;
}

static int
increment_soa_dn (const char *dn)
{
	char *soa_new;
	char *soa_old;
	int len, ret = -1;

	assert (dn && dn[0]);

	soa_old = load_soa_attribute (dn);
	if (!soa_old) {
		log_plugin ("couldn't increment SOA record at %s: not found", dn);
		return -1;
	}

	len = strlen (soa_old) + 32;
	soa_new = slapi_ch_malloc (len);
	if (soa_serial_increment (soa_old, soa_new, len) < 0) {
		if (errno == EINVAL)
			log_plugin ("invalid SOA record at %s: %s", dn, soa_old);
		else
			log_plugin ("couldn't increment SOA record at %s: %s", dn, strerror (errno));
		ret = -1;
	} else {
		ret = change_soa_attribute (dn, soa_old, soa_new);
	}

	slapi_ch_free_string (&soa_new);
	slapi_ch_free_string (&soa_old);

	return ret;
}

void
autoserial_post_delete (const char *dn)
{
	char *soa_dn;

	return_if_fail (dn && dn[0]);

	if (!dnsserial_enable)
		return;

	/* A DN that is an SOA? */
	if (present_in_soa_cache (dn)) {
		remove_from_soa_cache (dn);

	/* A DN underneath an SOA? */
	} else {
		soa_dn = ancestor_in_soa_cache (dn);
		if (soa_dn) {
			increment_soa_dn (soa_dn);
			slapi_ch_free_string (&soa_dn);
		}
	}
}

void
autoserial_post_modify (const char *dn, LDAPMod **mods)
{
	char *soa, *soa_dn;
	int present;

	return_if_fail (dn && dn[0]);

	if (!dnsserial_enable)
		return;

	/* Add or remove from cache as appropriate */
	soa = load_soa_attribute(dn);
	if (soa) {
		add_to_soa_cache (dn);
		slapi_ch_free_string (&soa);
		present = 1;
	} else {
		remove_from_soa_cache (dn);
		present = 0;
	}

	/* A DN underneath an SOA? */
	if (!present) {
		soa_dn = ancestor_in_soa_cache (dn);
		if (soa_dn) {
			increment_soa_dn (soa_dn);
			slapi_ch_free_string (&soa_dn);
		}
	}
}

void
autoserial_post_modrdn (const char *odn, const char *ndn)
{
	char *soa_dn;

	return_if_fail (odn && odn[0]);
	return_if_fail (ndn && ndn[0]);

	if (!dnsserial_enable)
		return;

	/* A DN that is an SOA? */
	if (present_in_soa_cache (odn)) {

		remove_from_soa_cache (odn);
		add_to_soa_cache (ndn);

	/* A DN underneath an SOA? */
	} else {
		soa_dn = ancestor_in_soa_cache (ndn);
		if (soa_dn) {
			increment_soa_dn (soa_dn);
			slapi_ch_free_string (&soa_dn);
		}
	}
}

void
autoserial_post_add (const char *dn)
{
	char *soa, *soa_dn;

	return_if_fail (dn && dn[0]);

	if (!dnsserial_enable)
		return;

	/* A DN that is an SOA? */
	soa = load_soa_attribute (dn);
	if (soa) {
		add_to_soa_cache (dn);
		slapi_ch_free_string (&soa);

	/* A DN underneath an SOA? */
	} else {
		soa_dn = ancestor_in_soa_cache (dn);
		if (soa_dn) {
			increment_soa_dn (soa_dn);
			slapi_ch_free_string (&soa_dn);
		}
	}
}

int
autoserial_config (const char *name, const char *value)
{
	return_val_if_fail (name, 0);

	if (strcmp ("soa-attribute", name) == 0 && value) {
		dnsserial_soa_attribute = value;
		return 1;


	} else if (strcmp ("base-dn", name) == 0 && value) {
		dnsserial_soa_base = value;
		return 1;

	} else if (strcmp ("enable-auto-serial", name) == 0 && !value) {
		dnsserial_enable = 1;
		return 1;
	}

	return 0;
}

void
autoserial_destroy (void)
{
	assert (dnsserial_mutex);
	slapi_lock_mutex (dnsserial_mutex);

		if (dnsserial_soa_cache)
			strset_destroy (dnsserial_soa_cache);
		dnsserial_soa_cache = NULL;

	slapi_unlock_mutex (dnsserial_mutex);

	slapi_destroy_mutex (dnsserial_mutex);
	dnsserial_mutex = NULL;
}

int
autoserial_init (void)
{
	if (!dnsserial_soa_base || !dnsserial_soa_base[0]) {
		log_plugin ("'base-dn' argument not specified");
		return -1;
	}

	assert (!dnsserial_mutex);
	dnsserial_mutex = slapi_new_mutex ();
	return_val_if_fail (dnsserial_mutex, -1);

	return 0;
}