/* Copyright (c) 2009 Open Information Security Foundation */

/**
 * This file provides a basic configuration system for the IDPS
 * engine.
 *
 * NOTE: Setting values should only be done from one thread during
 * engine initialization.  Multiple threads should be able access read
 * configuration data.  Allowing run time changes to the configuration
 * will require some locks.
 *
 * \author Endace Technology Limited - Jason Ish <jason.ish@endace.com>
 *
 * \todo Consider having the in-memory configuration database a direct
 *   reflection of the configuration file and moving command line
 *   parameters to a primary lookup table?
 */

#include <string.h>

#include "suricata-common.h"
#include "conf.h"
#include "util-unittest.h"
#include "util-debug.h"

static ConfNode *root = NULL;
static ConfNode *root_backup = NULL;

/**
 * \brief Initialize the configuration system.
 */
void
ConfInit(void)
{
    if (root != NULL) {
        SCLogDebug("already initialized");
        return;
    }
    root = ConfNodeNew();
    if (root == NULL) {
        SCLogError(SC_ERR_MEM_ALLOC,
            "ERROR: Failed to allocate memory for root configuration node, "
            "aborting.");
        exit(EXIT_FAILURE);
    }
    SCLogDebug("configuration module initialized");
}

/**
 * \brief Allocate a new configuration node.
 *
 * \retval An allocated configuration node on success, NULL on failure.
 */
ConfNode *
ConfNodeNew(void)
{
    ConfNode *new;

    new = calloc(1, sizeof(*new));
    if (new == NULL) {
        SCLogError(SC_ERR_MEM_ALLOC,
            "Error allocating memory for new configuration node");
        exit(EXIT_FAILURE);
    }
    TAILQ_INIT(&new->head);

    return new;
}

/**
 * \brief Free a ConfNode and all of its children.
 *
 * \param node The configuration node to free.
 */
void
ConfNodeFree(ConfNode *node)
{
    ConfNode *tmp;

    while ((tmp = TAILQ_FIRST(&node->head))) {
        TAILQ_REMOVE(&node->head, tmp, next);
        ConfNodeFree(tmp);
    }

    if (node->name != NULL)
        free(node->name);
    if (node->val != NULL)
        free(node->val);
    free(node);
}

/**
 * \brief Get a ConfNode by name.
 *
 * \param key The full name of the configuration node to lookup.
 *
 * \retval A pointer to ConfNode is found or NULL if the configuration
 *    node does not exist.
 */
ConfNode *
ConfGetNode(char *key)
{
    ConfNode *node = root;
    char *saveptr;
    char *token;

    /* Need to dup the key for tokenization... */
    char *tokstr = strdup(key);

    token = strtok_r(tokstr, ".", &saveptr);
    for (;;) {
        node = ConfNodeLookupChild(node, token);
        if (node == NULL)
            break;
        token = strtok_r(NULL, ".", &saveptr);
        if (token == NULL)
            break;
    }
    free(tokstr);
    return node;
}

/**
 * \brief Get the root configuration node.
 */
ConfNode *
ConfGetRootNode(void)
{
    return root;
}

/**
 * \brief Set a configuration value.
 *
 * \param name The name of the configuration parameter to set.
 * \param val The value of the configuration parameter.
 * \param allow_override Can a subsequent set override this value.
 *
 * \retval 1 if the value was set otherwise 0.
 */
int
ConfSet(char *name, char *val, int allow_override)
{
    ConfNode *parent = root;
    ConfNode *node;
    char *token;
    char *saveptr;

    /* First check if the node already exists. */
    node = ConfGetNode(name);
    if (node != NULL) {
        if (!node->allow_override) {
            return 0;
        }
        else {
            if (node->val != NULL)
                free(node->val);
            node->val = strdup(val);
            node->allow_override = allow_override;
            return 1;
        }
    }
    else {
        char *tokstr = strdup(name);
        token = strtok_r(tokstr, ".", &saveptr);
        node = ConfNodeLookupChild(parent, token);
        for (;;) {
            if (node == NULL) {
                node = ConfNodeNew();
                node->name = strdup(token);
                node->parent = parent;
                TAILQ_INSERT_TAIL(&parent->head, node, next);
                parent = node;
            }
            token = strtok_r(NULL, ".", &saveptr);
            if (token == NULL) {
                if (node->val != NULL)
                    free(node->val);
                node->val = strdup(val);
                node->allow_override = allow_override;
                break;
            }
            else {
                node = ConfNodeLookupChild(parent, token);
            }
        }
        free(tokstr);
    }

    SCLogDebug("configuration parameter '%s' set", name);

    return 1;
}

/**
 * \brief Retrieve the value of a configuration node.
 *
 * This function will return the value for a configuration node based
 * on the full name of the node.  It is possible that the value
 * returned could be NULL, this could happen if the requested node
 * does exist but is not a node that contains a value, but contains
 * children ConfNodes instead.
 *
 * \param name Name of configuration parameter to get.
 * \param vptr Pointer that will be set to the configuration value parameter.
 *   Note that this is just a reference to the actual value, not a copy.
 *
 * \retval 1 will be returned if the name is found, otherwise 0 will
 *   be returned.
 */
int
ConfGet(char *name, char **vptr)
{
    ConfNode *node = ConfGetNode(name);
    if (node == NULL) {
        SCLogDebug("failed to lookup configuration parameter '%s'", name);
        return 0;
    }
    else {
        *vptr = node->val;
        return 1;
    }
}

/**
 * \brief Retrieve a configuration value as an integer.
 *
 * \param name Name of configuration parameter to get.
 * \param val Pointer to an intmax_t that will be set the
 * configuration value.
 *
 * \retval 1 will be returned if the name is found and was properly
 * converted to an interger, otherwise 0 will be returned.
 */
int
ConfGetInt(char *name, intmax_t *val)
{
    char *strval;
    intmax_t tmpint;
    char *endptr;

    if (ConfGet(name, &strval) == 0)
        return 0;

    errno = 0;
    tmpint = strtoimax(strval, &endptr, 0);
    if (strval[0] == '\0' || *endptr != '\0')
        return 0;
    if (errno == ERANGE && (tmpint == INTMAX_MAX || tmpint == INTMAX_MIN))
        return 0;

    *val = tmpint;
    return 1;
}

/**
 * \brief Retrieve a configuration value as an boolen.
 *
 * \param name Name of configuration parameter to get.
 * \param val Pointer to an int that will be set to 1 for true, or 0
 * for false.
 *
 * \retval 1 will be returned if the name is found and was properly
 * converted to a boolean, otherwise 0 will be returned.
 */
int
ConfGetBool(char *name, int *val)
{
    char *strval;
    char *trues[] = {"1", "yes", "true", "on"};
    size_t u;

    *val = 0;
    if (ConfGet(name, &strval) != 1)
        return 0;

    for (u = 0; u < sizeof(trues) / sizeof(trues[0]); u++) {
        if (strcasecmp(strval, trues[u]) == 0) {
            *val = 1;
            break;
        }
    }

    return 1;
}

/**
 * \brief Remove (and free) the provided configuration node.
 */
void
ConfNodeRemove(ConfNode *node)
{
    if (node->parent != NULL)
        TAILQ_REMOVE(&node->parent->head, node, next);
    ConfNodeFree(node);
}

/**
 * \brief Remove a configuration parameter from the configuration db.
 *
 * \param name The name of the configuration parameter to remove.
 *
 * \retval Returns 1 if the parameter was removed, otherwise 0 is returned
 *   most likely indicating the parameter was not set.
 */
int
ConfRemove(char *name)
{
    ConfNode *node;

    node = ConfGetNode(name);
    if (node == NULL)
        return 0;
    else {
        ConfNodeRemove(node);
        return 1;
    }
}

/**
 * \brief Creates a backup of the conf_hash hash_table used by the conf API.
 */
void
ConfCreateContextBackup(void)
{
    root_backup = root;
    root = NULL;

    return;
}

/**
 * \brief Restores the backup of the hash_table present in backup_conf_hash
 *        back to conf_hash.
 */
void
ConfRestoreContextBackup(void)
{
    root = root_backup;

    return;
}

/**
 * \brief De-initializes the configuration system.
 */
void
ConfDeInit(void)
{
    if (root != NULL)
        ConfNodeFree(root);

    SCLogDebug("configuration module de-initialized");
}

static char *
ConfPrintNameArray(char **name_arr, int level)
{
    static char name[128*128];
    int i;

    name[0] = '\0';
    for (i = 0; i <= level; i++) {
        strlcat(name, name_arr[i], sizeof(name));
        if (i < level)
            strlcat(name, ".", sizeof(name));
    }

    return name;
}

/**
 * \brief Dump a configuration node and all its children.
 */
void
ConfNodeDump(ConfNode *node, const char *prefix)
{
    ConfNode *child;

    static char *name[128];
    static int level = -1;

    level++;
    TAILQ_FOREACH(child, &node->head, next) {
        name[level] = strdup(child->name);
        if (prefix == NULL) {
            printf("%s = %s\n", ConfPrintNameArray(name, level),
                child->val);
        }
        else {
            printf("%s.%s = %s\n", prefix,
                ConfPrintNameArray(name, level), child->val);
        }
        ConfNodeDump(child, prefix);
        free(name[level]);
    }
    level--;
}

/**
 * \brief Dump configuration to stdout.
 */
void
ConfDump(void)
{
    ConfNodeDump(root, NULL);
}

/**
 * \brief Lookup a child configuration node by name.
 *
 * Given a ConfNode this function will lookup an immediate child
 * ConfNode by name and return the child ConfNode.
 *
 * \param node The parent configuration node.
 * \param name The name of the child node to lookup.
 *
 * \retval A pointer the child ConfNode if found otherwise NULL.
 */
ConfNode *
ConfNodeLookupChild(ConfNode *node, const char *name)
{
    ConfNode *child;

    TAILQ_FOREACH(child, &node->head, next) {
        if (strcmp(child->name, name) == 0)
            return child;
    }

    return NULL;
}

/**
 * \brief Lookup the value of a child configuration node by name.
 *
 * Given a parent ConfNode this function will return the value of a
 * child configuration node by name returning a reference to that
 * value.
 *
 * \param node The parent configuration node.
 * \param name The name of the child node to lookup.
 *
 * \retval A pointer the child ConfNodes value if found otherwise NULL.
 */
const char *
ConfNodeLookupChildValue(ConfNode *node, const char *name)
{
    ConfNode *child;

    child = ConfNodeLookupChild(node, name);
    if (child != NULL)
        return child->val;

    return NULL;
}

#ifdef UNITTESTS

/**
 * Lookup a non-existant value.
 */
static int
ConfTestGetNonExistant(void)
{
    char name[] = "non-existant-value";
    char *value;

    return !ConfGet(name, &value);
}

/**
 * Set then lookup a value.
 */
static int
ConfTestSetAndGet(void)
{
    char name[] = "some-name";
    char value[] = "some-value";
    char *value0;

    if (ConfSet(name, value, 1) != 1)
        return 0;
    if (ConfGet(name, &value0) != 1)
        return 0;
    if (strcmp(value, value0) != 0)
        return 0;

    /* Cleanup. */
    ConfRemove(name);

    return 1;
}

/**
 * Test that overriding a value is allowed provided allow_override is
 * true and that the config parameter gets the new value.
 */
static int
ConfTestOverrideValue1(void)
{
    char name[] = "some-name";
    char value0[] = "some-value";
    char value1[] = "new-value";
    char *val;
    int rc;

    if (ConfSet(name, value0, 1) != 1)
        return 0;
    if (ConfSet(name, value1, 1) != 1)
        return 0;
    if (ConfGet(name, &val) != 1)
        return 0;

    rc = !strcmp(val, value1);

    /* Cleanup. */
    ConfRemove(name);

    return rc;
}

/**
 * Test that overriding a value is not allowed provided that
 * allow_override is false and make sure the value was not overrided.
 */
static int
ConfTestOverrideValue2(void)
{
    char name[] = "some-name";
    char value0[] = "some-value";
    char value1[] = "new-value";
    char *val;
    int rc;

    if (ConfSet(name, value0, 0) != 1)
        return 0;
    if (ConfSet(name, value1, 1) != 0)
        return 0;
    if (ConfGet(name, &val) != 1)
        return 0;

    rc = !strcmp(val, value0);

    /* Cleanup. */
    ConfRemove(name);

    return rc;
}

/**
 * Test retrieving an integer value from the configuration db.
 */
static int
ConfTestGetInt(void)
{
    char name[] = "some-int.x";
    intmax_t val;

    if (ConfSet(name, "0", 1) != 1)
        return 0;
    if (ConfGetInt(name, &val) != 1)
        return 0;
    return 1;
    if (val != 0)
        return 0;

    if (ConfSet(name, "-1", 1) != 1)
        return 0;
    if (ConfGetInt(name, &val) != 1)
        return 0;
    if (val != -1)
        return 0;

    if (ConfSet(name, "0xffff", 1) != 1)
        return 0;
    if (ConfGetInt(name, &val) != 1)
        return 0;
    if (val != 0xffff)
        return 0;

    if (ConfSet(name, "not-an-int", 1) != 1)
        return 0;
    if (ConfGetInt(name, &val) != 0)
        return 0;

    return 1;
}

/**
 * Test retrieving a boolean value from the configuration db.
 */
static int
ConfTestGetBool(void)
{
    char name[] = "some-bool";
    char *trues[] = {
        "1",
        "on", "ON",
        "yes", "YeS",
        "true", "TRUE",
    };
    char *falses[] = {
        "0",
        "something",
        "off", "OFF",
        "false", "FalSE",
        "no", "NO",
    };
    int val;
    size_t u;

    for (u = 0; u < sizeof(trues) / sizeof(trues[0]); u++) {
        if (ConfSet(name, trues[u], 1) != 1)
            return 0;
        if (ConfGetBool(name, &val) != 1)
            return 0;
        if (val != 1)
            return 0;
    }

    for (u = 0; u < sizeof(falses) / sizeof(falses[0]); u++) {
        if (ConfSet(name, falses[u], 1) != 1)
            return 0;
        if (ConfGetBool(name, &val) != 1)
            return 0;
        if (val != 0)
            return 0;
    }

    return 1;
}

static int
ConfNodeLookupChildTest(void)
{
    char *test_vals[] = { "one", "two", "three" };
    size_t u;

    ConfNode *parent = ConfNodeNew();
    ConfNode *child;

    for (u = 0; u < sizeof(test_vals)/sizeof(test_vals[0]); u++) {
        child = ConfNodeNew();
        child->name = strdup(test_vals[u]);
        child->val = strdup(test_vals[u]);
        TAILQ_INSERT_TAIL(&parent->head, child, next);
    }

    child = ConfNodeLookupChild(parent, "one");
    if (child == NULL)
        return 0;
    if (strcmp(child->name, "one") != 0)
        return 0;
    if (strcmp(child->val, "one") != 0)
        return 0;

    child = ConfNodeLookupChild(parent, "two");
    if (child == NULL)
        return 0;
    if (strcmp(child->name, "two") != 0)
        return 0;
    if (strcmp(child->val, "two") != 0)
        return 0;

    child = ConfNodeLookupChild(parent, "three");
    if (child == NULL)
        return 0;
    if (strcmp(child->name, "three") != 0)
        return 0;
    if (strcmp(child->val, "three") != 0)
        return 0;

    child = ConfNodeLookupChild(parent, "four");
    if (child != NULL)
        return 0;

    ConfNodeFree(parent);

    return 1;
}

static int
ConfNodeLookupChildValueTest(void)
{
    char *test_vals[] = { "one", "two", "three" };
    size_t u;

    ConfNode *parent = ConfNodeNew();
    ConfNode *child;
    const char *value;

    for (u = 0; u < sizeof(test_vals)/sizeof(test_vals[0]); u++) {
        child = ConfNodeNew();
        child->name = strdup(test_vals[u]);
        child->val = strdup(test_vals[u]);
        TAILQ_INSERT_TAIL(&parent->head, child, next);
    }

    value = (char *)ConfNodeLookupChildValue(parent, "one");
    if (value == NULL)
        return 0;
    if (strcmp(value, "one") != 0)
        return 0;

    value = (char *)ConfNodeLookupChildValue(parent, "two");
    if (value == NULL)
        return 0;
    if (strcmp(value, "two") != 0)
        return 0;

    value = (char *)ConfNodeLookupChildValue(parent, "three");
    if (value == NULL)
        return 0;
    if (strcmp(value, "three") != 0)
        return 0;

    value = (char *)ConfNodeLookupChildValue(parent, "four");
    if (value != NULL)
        return 0;

    ConfNodeFree(parent);

    return 1;
}

/**
 * Test the removal of a configuration node.
 */
static int
ConfNodeRemoveTest(void)
{
    ConfCreateContextBackup();
    ConfInit();

    if (ConfSet("some.nested.parameter", "blah", 1) != 1)
        return 0;

    ConfNode *node = ConfGetNode("some.nested.parameter");
    if (node == NULL)
        return 0;
    ConfNodeRemove(node);

    node = ConfGetNode("some.nested.parameter");
    if (node != NULL)
        return 0;

    ConfDeInit();
    ConfRestoreContextBackup();

    return 1;
}

void
ConfRegisterTests(void)
{
    UtRegisterTest("ConfTestGetNonExistant", ConfTestGetNonExistant, 1);
    UtRegisterTest("ConfTestSetAndGet", ConfTestSetAndGet, 1);
    UtRegisterTest("ConfTestOverrideValue1", ConfTestOverrideValue1, 1);
    UtRegisterTest("ConfTestOverrideValue2", ConfTestOverrideValue2, 1);
    UtRegisterTest("ConfTestGetInt", ConfTestGetInt, 1);
    UtRegisterTest("ConfTestGetBool", ConfTestGetBool, 1);
    UtRegisterTest("ConfNodeLookupChildTest", ConfNodeLookupChildTest, 1);
    UtRegisterTest("ConfNodeLookupChildValueTest", ConfNodeLookupChildValueTest, 1);
    UtRegisterTest("ConfNodeRemoveTest", ConfNodeRemoveTest, 1);
}

#endif /* UNITTESTS */