/*
 * (C) Copyright 2012
 * Joe Hershberger, National Instruments, joe.hershberger@ni.com
 *
 * SPDX-License-Identifier:     GPL-2.0+
 */

#include <linux/string.h>
#include <linux/ctype.h>

#ifdef USE_HOSTCC /* Eliminate "ANSI does not permit..." warnings */
#include <stdint.h>
#include <stdio.h>
#include "fw_env_private.h"
#include "fw_env.h"
#include <env_attr.h>
#include <env_flags.h>
#define env_get fw_getenv
#define ARRAY_SIZE(x) (sizeof(x) / sizeof((x)[0]))
#else
#include <common.h>
#include <environment.h>
#endif

#ifdef CONFIG_CMD_NET
#define ENV_FLAGS_NET_VARTYPE_REPS "im"
#else
#define ENV_FLAGS_NET_VARTYPE_REPS ""
#endif

static const char env_flags_vartype_rep[] = "sdxb" ENV_FLAGS_NET_VARTYPE_REPS;
static const char env_flags_varaccess_rep[] = "aroc";
static const int env_flags_varaccess_mask[] = {
        0,
        ENV_FLAGS_VARACCESS_PREVENT_DELETE |
                ENV_FLAGS_VARACCESS_PREVENT_CREATE |
                ENV_FLAGS_VARACCESS_PREVENT_OVERWR,
        ENV_FLAGS_VARACCESS_PREVENT_DELETE |
                ENV_FLAGS_VARACCESS_PREVENT_OVERWR,
        ENV_FLAGS_VARACCESS_PREVENT_DELETE |
                ENV_FLAGS_VARACCESS_PREVENT_NONDEF_OVERWR};

#ifdef CONFIG_CMD_ENV_FLAGS
static const char * const env_flags_vartype_names[] = {
        "string",
        "decimal",
        "hexadecimal",
        "boolean",
#ifdef CONFIG_CMD_NET
        "IP address",
        "MAC address",
#endif
};
static const char * const env_flags_varaccess_names[] = {
        "any",
        "read-only",
        "write-once",
        "change-default",
};

/*
 * Print the whole list of available type flags.
 */
void env_flags_print_vartypes(void)
{
        enum env_flags_vartype curtype = (enum env_flags_vartype)0;

        while (curtype != env_flags_vartype_end) {
                printf("\t%c   -\t%s\n", env_flags_vartype_rep[curtype],
                        env_flags_vartype_names[curtype]);
                curtype++;
        }
}

/*
 * Print the whole list of available access flags.
 */
void env_flags_print_varaccess(void)
{
        enum env_flags_varaccess curaccess = (enum env_flags_varaccess)0;

        while (curaccess != env_flags_varaccess_end) {
                printf("\t%c   -\t%s\n", env_flags_varaccess_rep[curaccess],
                        env_flags_varaccess_names[curaccess]);
                curaccess++;
        }
}

/*
 * Return the name of the type.
 */
const char *env_flags_get_vartype_name(enum env_flags_vartype type)
{
        return env_flags_vartype_names[type];
}

/*
 * Return the name of the access.
 */
const char *env_flags_get_varaccess_name(enum env_flags_varaccess access)
{
        return env_flags_varaccess_names[access];
}
#endif /* CONFIG_CMD_ENV_FLAGS */

/*
 * Parse the flags string from a .flags attribute list into the vartype enum.
 */
enum env_flags_vartype env_flags_parse_vartype(const char *flags)
{
        char *type;

        if (strlen(flags) <= ENV_FLAGS_VARTYPE_LOC)
                return env_flags_vartype_string;

        type = strchr(env_flags_vartype_rep,
                flags[ENV_FLAGS_VARTYPE_LOC]);

        if (type != NULL)
                return (enum env_flags_vartype)
                        (type - &env_flags_vartype_rep[0]);

        printf("## Warning: Unknown environment variable type '%c'\n",
                flags[ENV_FLAGS_VARTYPE_LOC]);
        return env_flags_vartype_string;
}

/*
 * Parse the flags string from a .flags attribute list into the varaccess enum.
 */
enum env_flags_varaccess env_flags_parse_varaccess(const char *flags)
{
        char *access;

        if (strlen(flags) <= ENV_FLAGS_VARACCESS_LOC)
                return env_flags_varaccess_any;

        access = strchr(env_flags_varaccess_rep,
                flags[ENV_FLAGS_VARACCESS_LOC]);

        if (access != NULL)
                return (enum env_flags_varaccess)
                        (access - &env_flags_varaccess_rep[0]);

        printf("## Warning: Unknown environment variable access method '%c'\n",
                flags[ENV_FLAGS_VARACCESS_LOC]);
        return env_flags_varaccess_any;
}

/*
 * Parse the binary flags from a hash table entry into the varaccess enum.
 */
enum env_flags_varaccess env_flags_parse_varaccess_from_binflags(int binflags)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(env_flags_varaccess_mask); i++)
                if (env_flags_varaccess_mask[i] ==
                    (binflags & ENV_FLAGS_VARACCESS_BIN_MASK))
                        return (enum env_flags_varaccess)i;

        printf("Warning: Non-standard access flags. (0x%x)\n",
                binflags & ENV_FLAGS_VARACCESS_BIN_MASK);

        return env_flags_varaccess_any;
}

static inline int is_hex_prefix(const char *value)
{
        return value[0] == '0' && (value[1] == 'x' || value[1] == 'X');
}

static void skip_num(int hex, const char *value, const char **end,
        int max_digits)
{
        int i;

        if (hex && is_hex_prefix(value))
                value += 2;

        for (i = max_digits; i != 0; i--) {
                if (hex && !isxdigit(*value))
                        break;
                if (!hex && !isdigit(*value))
                        break;
                value++;
        }
        if (end != NULL)
                *end = value;
}

#ifdef CONFIG_CMD_NET
int eth_validate_ethaddr_str(const char *addr)
{
        const char *end;
        const char *cur;
        int i;

        cur = addr;
        for (i = 0; i < 6; i++) {
                skip_num(1, cur, &end, 2);
                if (cur == end)
                        return -1;
                if (cur + 2 == end && is_hex_prefix(cur))
                        return -1;
                if (i != 5 && *end != ':')
                        return -1;
                if (i == 5 && *end != '\0')
                        return -1;
                cur = end + 1;
        }

        return 0;
}
#endif

/*
 * Based on the declared type enum, validate that the value string complies
 * with that format
 */
static int _env_flags_validate_type(const char *value,
        enum env_flags_vartype type)
{
        const char *end;
#ifdef CONFIG_CMD_NET
        const char *cur;
        int i;
#endif

        switch (type) {
        case env_flags_vartype_string:
                break;
        case env_flags_vartype_decimal:
                skip_num(0, value, &end, -1);
                if (*end != '\0')
                        return -1;
                break;
        case env_flags_vartype_hex:
                skip_num(1, value, &end, -1);
                if (*end != '\0')
                        return -1;
                if (value + 2 == end && is_hex_prefix(value))
                        return -1;
                break;
        case env_flags_vartype_bool:
                if (value[0] != '1' && value[0] != 'y' && value[0] != 't' &&
                    value[0] != 'Y' && value[0] != 'T' &&
                    value[0] != '0' && value[0] != 'n' && value[0] != 'f' &&
                    value[0] != 'N' && value[0] != 'F')
                        return -1;
                if (value[1] != '\0')
                        return -1;
                break;
#ifdef CONFIG_CMD_NET
        case env_flags_vartype_ipaddr:
                cur = value;
                for (i = 0; i < 4; i++) {
                        skip_num(0, cur, &end, 3);
                        if (cur == end)
                                return -1;
                        if (i != 3 && *end != '.')
                                return -1;
                        if (i == 3 && *end != '\0')
                                return -1;
                        cur = end + 1;
                }
                break;
        case env_flags_vartype_macaddr:
                if (eth_validate_ethaddr_str(value))
                        return -1;
                break;
#endif
        case env_flags_vartype_end:
                return -1;
        }

        /* OK */
        return 0;
}

/*
 * Look for flags in a provided list and failing that the static list
 */
static inline int env_flags_lookup(const char *flags_list, const char *name,
        char *flags)
{
        int ret = 1;

        if (!flags)
                /* bad parameter */
                return -1;

        /* try the env first */
        if (flags_list)
                ret = env_attr_lookup(flags_list, name, flags);

        if (ret != 0)
                /* if not found in the env, look in the static list */
                ret = env_attr_lookup(ENV_FLAGS_LIST_STATIC, name, flags);

        return ret;
}

#ifdef USE_HOSTCC /* Functions only used from tools/env */
/*
 * Look up any flags directly from the .flags variable and the static list
 * and convert them to the vartype enum.
 */
enum env_flags_vartype env_flags_get_type(const char *name)
{
        const char *flags_list = env_get(ENV_FLAGS_VAR);
        char flags[ENV_FLAGS_ATTR_MAX_LEN + 1];

        if (env_flags_lookup(flags_list, name, flags))
                return env_flags_vartype_string;

        if (strlen(flags) <= ENV_FLAGS_VARTYPE_LOC)
                return env_flags_vartype_string;

        return env_flags_parse_vartype(flags);
}

/*
 * Look up the access of a variable directly from the .flags var.
 */
enum env_flags_varaccess env_flags_get_varaccess(const char *name)
{
        const char *flags_list = env_get(ENV_FLAGS_VAR);
        char flags[ENV_FLAGS_ATTR_MAX_LEN + 1];

        if (env_flags_lookup(flags_list, name, flags))
                return env_flags_varaccess_any;

        if (strlen(flags) <= ENV_FLAGS_VARACCESS_LOC)
                return env_flags_varaccess_any;

        return env_flags_parse_varaccess(flags);
}

/*
 * Validate that the proposed new value for "name" is valid according to the
 * defined flags for that variable, if any.
 */
int env_flags_validate_type(const char *name, const char *value)
{
        enum env_flags_vartype type;

        if (value == NULL)
                return 0;
        type = env_flags_get_type(name);
        if (_env_flags_validate_type(value, type) < 0) {
                printf("## Error: flags type check failure for "
                        "\"%s\" <= \"%s\" (type: %c)\n",
                        name, value, env_flags_vartype_rep[type]);
                return -1;
        }
        return 0;
}

/*
 * Validate that the proposed access to variable "name" is valid according to
 * the defined flags for that variable, if any.
 */
int env_flags_validate_varaccess(const char *name, int check_mask)
{
        enum env_flags_varaccess access;
        int access_mask;

        access = env_flags_get_varaccess(name);
        access_mask = env_flags_varaccess_mask[access];

        return (check_mask & access_mask) != 0;
}

/*
 * Validate the parameters to "env set" directly
 */
int env_flags_validate_env_set_params(char *name, char * const val[], int count)
{
        if ((count >= 1) && val[0] != NULL) {
                enum env_flags_vartype type = env_flags_get_type(name);

                /*
                 * we don't currently check types that need more than
                 * one argument
                 */
                if (type != env_flags_vartype_string && count > 1) {
                        printf("## Error: too many parameters for setting \"%s\"\n",
                               name);
                        return -1;
                }
                return env_flags_validate_type(name, val[0]);
        }
        /* ok */
        return 0;
}

#else /* !USE_HOSTCC - Functions only used from lib/hashtable.c */

/*
 * Parse the flag charachters from the .flags attribute list into the binary
 * form to be stored in the environment entry->flags field.
 */
static int env_parse_flags_to_bin(const char *flags)
{
        int binflags;

        binflags = env_flags_parse_vartype(flags) & ENV_FLAGS_VARTYPE_BIN_MASK;
        binflags |= env_flags_varaccess_mask[env_flags_parse_varaccess(flags)];

        return binflags;
}

static int first_call = 1;
static const char *flags_list;

/*
 * Look for possible flags for a newly added variable
 * This is called specifically when the variable did not exist in the hash
 * previously, so the blanket update did not find this variable.
 */
void env_flags_init(ENTRY *var_entry)
{
        const char *var_name = var_entry->key;
        char flags[ENV_FLAGS_ATTR_MAX_LEN + 1] = "";
        int ret = 1;

        if (first_call) {
                flags_list = env_get(ENV_FLAGS_VAR);
                first_call = 0;
        }
        /* look in the ".flags" and static for a reference to this variable */
        ret = env_flags_lookup(flags_list, var_name, flags);

        /* if any flags were found, set the binary form to the entry */
        if (!ret && strlen(flags))
                var_entry->flags = env_parse_flags_to_bin(flags);
}

/*
 * Called on each existing env var prior to the blanket update since removing
 * a flag in the flag list should remove its flags.
 */
static int clear_flags(ENTRY *entry)
{
        entry->flags = 0;

        return 0;
}

/*
 * Call for each element in the list that defines flags for a variable
 */
static int set_flags(const char *name, const char *value, void *priv)
{
        ENTRY e, *ep;

        e.key   = name;
        e.data  = NULL;
        e.callback = NULL;
        hsearch_r(e, FIND, &ep, &env_htab, 0);

        /* does the env variable actually exist? */
        if (ep != NULL) {
                /* the flag list is empty, so clear the flags */
                if (value == NULL || strlen(value) == 0)
                        ep->flags = 0;
                else
                        /* assign the requested flags */
                        ep->flags = env_parse_flags_to_bin(value);
        }

        return 0;
}

static int on_flags(const char *name, const char *value, enum env_op op,
        int flags)
{
        /* remove all flags */
        hwalk_r(&env_htab, clear_flags);

        /* configure any static flags */
        env_attr_walk(ENV_FLAGS_LIST_STATIC, set_flags, NULL);
        /* configure any dynamic flags */
        env_attr_walk(value, set_flags, NULL);

        return 0;
}
U_BOOT_ENV_CALLBACK(flags, on_flags);

/*
 * Perform consistency checking before creating, overwriting, or deleting an
 * environment variable. Called as a callback function by hsearch_r() and
 * hdelete_r(). Returns 0 in case of success, 1 in case of failure.
 * When (flag & H_FORCE) is set, do not print out any error message and force
 * overwriting of write-once variables.
 */

int env_flags_validate(const ENTRY *item, const char *newval, enum env_op op,
        int flag)
{
        const char *name;
        const char *oldval = NULL;

        if (op != env_op_create)
                oldval = item->data;

        name = item->key;

        /* Default value for NULL to protect string-manipulating functions */
        newval = newval ? : "";

        /* validate the value to match the variable type */
        if (op != env_op_delete) {
                enum env_flags_vartype type = (enum env_flags_vartype)
                        (ENV_FLAGS_VARTYPE_BIN_MASK & item->flags);

                if (_env_flags_validate_type(newval, type) < 0) {
                        printf("## Error: flags type check failure for "
                                "\"%s\" <= \"%s\" (type: %c)\n",
                                name, newval, env_flags_vartype_rep[type]);
                        return -1;
                }
        }

        /* check for access permission */
#ifndef CONFIG_ENV_ACCESS_IGNORE_FORCE
        if (flag & H_FORCE)
                return 0;
#endif
        switch (op) {
        case env_op_delete:
                if (item->flags & ENV_FLAGS_VARACCESS_PREVENT_DELETE) {
                        printf("## Error: Can't delete \"%s\"\n", name);
                        return 1;
                }
                break;
        case env_op_overwrite:
                if (item->flags & ENV_FLAGS_VARACCESS_PREVENT_OVERWR) {
                        printf("## Error: Can't overwrite \"%s\"\n", name);
                        return 1;
                } else if (item->flags &
                    ENV_FLAGS_VARACCESS_PREVENT_NONDEF_OVERWR) {
                        const char *defval = env_get_default(name);

                        if (defval == NULL)
                                defval = "";
                        printf("oldval: %s  defval: %s\n", oldval, defval);
                        if (strcmp(oldval, defval) != 0) {
                                printf("## Error: Can't overwrite \"%s\"\n",
                                        name);
                                return 1;
                        }
                }
                break;
        case env_op_create:
                if (item->flags & ENV_FLAGS_VARACCESS_PREVENT_CREATE) {
                        printf("## Error: Can't create \"%s\"\n", name);
                        return 1;
                }
                break;
        }

        return 0;
}

#endif