/*
 * Copyright (c) 2013, Google, Inc. All rights reserved
 *
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files
 * (the "Software"), to deal in the Software without restriction,
 * including without limitation the rights to use, copy, modify, merge,
 * publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so,
 * subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
#include <debug.h>
#include <trace.h>
#include <assert.h>
#include <err.h>
#include <string.h>
#include <malloc.h>
#include <stdio.h>
#include <stdlib.h>
#include <list.h>
#include <lib/bio.h>
#include <lib/cksum.h>
#include <lib/sysparam.h>
#include <lk/init.h>

/* implementation of system parameter block, stored on a block device */
/* sysparams are simple name/value pairs, with the data unstructured */
#define LOCAL_TRACE 0

#define SYSPARAM_MAGIC 'SYSP'

#define SYSPARAM_FLAG_LOCK 0x1

struct sysparam_phys {
	uint32_t magic;
	uint32_t crc32; // crc of entire structure below crc including padding
	uint32_t flags;
	uint16_t namelen;
	uint16_t datalen;

	//uint8_t name[namelen];
	// 0 padding to next multiple of 4
	//uint8_t data[data];
	// 0 padding to next multiple of 4

	uint8_t namedata[0];
};

/* a copy we keep in memory */
struct sysparam {
	struct list_node node;

	uint32_t flags;

	char *name;

	size_t datalen;
	void *data;

	/* in memory size to hold this structure, the name string, and the data */
	size_t memlen;
};

/* global state */
static struct {
	struct list_node list;

	bool dirty;

	bdev_t *bdev;
	off_t offset;
	size_t len;
} params;

static void sysparam_init(uint level)
{
	list_initialize(&params.list);
}

LK_INIT_HOOK(sysparam, &sysparam_init, LK_INIT_LEVEL_THREADING);

static inline bool sysparam_is_locked(const struct sysparam *param)
{
	return param->flags & SYSPARAM_FLAG_LOCK;
}

static inline size_t sysparam_len(const struct sysparam_phys *sp)
{
	size_t len = sizeof(struct sysparam_phys);

	len += ROUNDUP(sp->namelen, 4);
	len += ROUNDUP(sp->datalen, 4);

	return len;
}

static inline uint32_t sysparam_crc32(const struct sysparam_phys *sp)
{
	size_t len = sysparam_len(sp);

	LTRACEF("len %d\n", len);
	uint32_t sum = crc32(0, (const void *)&sp->flags, len - 8);
	LTRACEF("sum is 0x%x\n", sum);

	return sum;
}

static struct sysparam *sysparam_create(const char *name, size_t namelen, const void *data, size_t datalen, uint32_t flags)
{
	struct sysparam *param = malloc(sizeof(struct sysparam));
	if (!param)
		return NULL;

	param->flags = flags;
	param->memlen = sizeof(struct sysparam);

	param->name = malloc(namelen + 1);
	if (!param->name) {
		free(param);
		return NULL;
	}
	param->memlen += namelen + 1;

	memcpy(param->name, name, namelen);
	param->name[namelen] = '\0';

	param->datalen = datalen;
	size_t alloclen = ROUNDUP(datalen, 4); /* allocate a multiple of 4 for padding purposes */
	param->data = malloc(alloclen);
	if (!param->data) {
		free(param->name);
		free(param);
		return NULL;
	}
	param->memlen += alloclen;

	memcpy(param->data, data, datalen);
	memset((char *)param->data + datalen, 0, alloclen - datalen); /* zero out the trailing space */

	return param;
}

static struct sysparam *sysparam_read_phys(const struct sysparam_phys *sp)
{
	return sysparam_create((const char *)sp->namedata, sp->namelen, sp->namedata + ROUNDUP(sp->namelen, 4), sp->datalen, sp->flags);
}

static struct sysparam *sysparam_find(const char *name)
{
	struct sysparam *param;
	list_for_every_entry(&params.list, param, struct sysparam, node) {
		if (strcmp(name, param->name) == 0)
			return param;
	}

	return NULL;
}

status_t sysparam_scan(bdev_t *bdev, off_t offset, size_t len)
{
	status_t err = NO_ERROR;

	LTRACEF("bdev %p (%s), offset 0x%llx, len 0x%zx\n", bdev, bdev->name, offset, len);

	DEBUG_ASSERT(bdev);
	DEBUG_ASSERT(len > 0);
	DEBUG_ASSERT(offset + len <= bdev->total_size);
	DEBUG_ASSERT((offset % bdev->block_size) == 0);

	params.bdev = bdev;
	params.offset = offset;
	params.len = len;
	params.dirty = false;

	/* allocate a len sized block */
	uint8_t *buf = malloc(len);
	if (!buf)
		return ERR_NO_MEMORY;

	/* read in the sector at the scan offset */
	err = bio_read(bdev, buf, offset, len);
	if (err < (ssize_t)len) {
		err = ERR_IO;
		goto err;
	}

	LTRACEF("looking for sysparams in block:\n");
	if (LOCAL_TRACE)
		hexdump(buf, len);

	size_t pos = 0;
	while (pos < len) {
		struct sysparam_phys *sp = (struct sysparam_phys *)(buf + pos);

		/* examine the sysparam entry, making sure it's valid */
		if (sp->magic != SYSPARAM_MAGIC) {
			pos += 4; /* try searching in the next spot */
			//LTRACEF("failed magic check\n");
			continue;
		}

		/* looks valid, see if length is sane */
		size_t splen = sysparam_len(sp);
		if (pos + splen > offset + len) {
			/* length exceeds the size of the area */
			LTRACEF("param at 0x%x: bad length\n", pos);
			break;
		}

		pos += splen;

		/* calculate a checksum of it */
		uint32_t sum = sysparam_crc32(sp);

		if (sp->crc32 != sum) {
			/* failed checksum */
			LTRACEF("param at 0x%x: failed checksum\n", pos - splen);
			continue;
		}

		LTRACEF("got param at offset 0x%zx\n", pos - splen);

		struct sysparam *param = sysparam_read_phys(sp);
		if (!param) {
			LTRACEF("param at 0x%x: failed to make memory copy\n", pos - splen);
			err = ERR_NO_MEMORY;
			break;
		}

		list_add_tail(&params.list, &param->node);
	}


err:
	free(buf);

	LTRACE_EXIT;
	return err;
}

status_t sysparam_reload(void)
{
	if (params.bdev == NULL)
		return ERR_INVALID_ARGS;
	if (params.len == 0)
		return ERR_INVALID_ARGS;

	/* wipe out the existing memory entries */
	struct sysparam *param;
	struct sysparam *temp;
	list_for_every_entry_safe(&params.list, param, temp, struct sysparam, node) {
		list_delete(&param->node);

		free(param->name);
		free(param->data);
		free(param);
	}

	/* reset the list back to scratch */
	params.dirty = false;

	status_t err = sysparam_scan(params.bdev, params.offset, params.len);

	return err;
}

ssize_t sysparam_read(const char *name, void *data, size_t len)
{
	struct sysparam *param;

	param = sysparam_find(name);
	if (!param)
		return ERR_NOT_FOUND;

	size_t toread = MIN(len, param->datalen);
	memcpy(data, param->data, toread);

	return toread;
}

ssize_t sysparam_length(const char *name)
{
	struct sysparam *param;

	param = sysparam_find(name);
	if (!param)
		return ERR_NOT_FOUND;

	return param->datalen;
}

status_t sysparam_get_ptr(const char *name, const void **ptr, size_t *len)
{
	struct sysparam *param;

	param = sysparam_find(name);
	if (!param)
		return ERR_NOT_FOUND;

	if (ptr)
		*ptr = param->data;
	if (len)
		*len = param->datalen;

	return NO_ERROR;
}

#if SYSPARAM_ALLOW_WRITE

/* write all of the parameters in memory to the space reserved in flash */
status_t sysparam_write(void)
{
	if (params.bdev == NULL)
		return ERR_INVALID_ARGS;
	if (params.len == 0)
		return ERR_INVALID_ARGS;

	if (!params.dirty)
		return NO_ERROR;

	/* preflight the length, make sure we have enough space */
	struct sysparam *param;
	off_t total_len = 0;
	list_for_every_entry(&params.list, param, struct sysparam, node) {
		total_len += sizeof(struct sysparam_phys);
		total_len += ROUNDUP(strlen(param->name), 4);
		total_len += ROUNDUP(param->datalen, 4);
	}

	if (total_len > params.len)
		return ERR_NO_MEMORY;

	/* allocate a buffer to stage it */
	uint8_t *buf = calloc(1, params.len);
	if (!buf) {
		TRACEF("error allocating buffer to stage write\n");
		return ERR_NO_MEMORY;
	}

	/* erase the block device area this covers */
	ssize_t err = bio_erase(params.bdev, params.offset, params.len);
	if (err < (ssize_t)params.len) {
		TRACEF("error erasing sysparam area\n");
		free(buf);
		return ERR_IO;
	}

	/* serialize all of the parameters */
	off_t pos = 0;
	list_for_every_entry(&params.list, param, struct sysparam, node) {
		struct sysparam_phys phys;

		/* start filling out a struct */
		phys.magic = SYSPARAM_MAGIC;
		phys.crc32 = 0;
		phys.flags = param->flags;
		phys.namelen = strlen(param->name);
		phys.datalen = param->datalen;

		/* calculate the crc of the entire thing + padding */
		uint32_t zero = 0;
		uint32_t sum = crc32(0, (const void *)&phys.flags, 8);
		sum = crc32(sum, (const void *)param->name, strlen(param->name));
		if (strlen(param->name) % 4)
			sum = crc32(sum, (const void *)&zero, 4 - (strlen(param->name) % 4));
		sum = crc32(sum, (const void *)param->data, ROUNDUP(param->datalen, 4));
		phys.crc32 = sum;

		/* structure portion */
		memcpy(buf + pos, &phys, sizeof(struct sysparam_phys));
		pos += sizeof(struct sysparam_phys);

		/* name portion */
		memcpy(buf + pos, param->name, strlen(param->name));
		pos += ROUNDUP(strlen(param->name), 2);
		if (pos % 4) {
			/* write 2 zeros to realign */
			pos += 2;
		}

		/* data portion */
		memcpy(buf + pos, param->data, param->datalen);
		pos += ROUNDUP(param->datalen, 4);
	}

	/* write the block out */
	bio_write(params.bdev, buf, params.offset, params.len);

	free(buf);

	params.dirty = false;

	return NO_ERROR;
}

status_t sysparam_add(const char *name, const void *value, size_t len)
{
	struct sysparam *param;

	param = sysparam_find(name);
	if (param)
		return ERR_ALREADY_EXISTS;

	param = sysparam_create(name, strlen(name), value, len, 0);
	if (!param)
		return ERR_NO_MEMORY;

	list_add_tail(&params.list, &param->node);

	params.dirty = true;

	return NO_ERROR;
}

status_t sysparam_remove(const char *name)
{
	struct sysparam *param;

	param = sysparam_find(name);
	if (!param)
		return ERR_NOT_FOUND;

	if (sysparam_is_locked(param))
		return ERR_NOT_ALLOWED;

	list_delete(&param->node);

	free(param->name);
	free(param->data);
	free(param);

	params.dirty = true;

	return NO_ERROR;
}

status_t sysparam_lock(const char *name)
{
	struct sysparam *param;

	param = sysparam_find(name);
	if (!param)
		return ERR_NOT_FOUND;

	/* set the lock bit if it isn't already */
	if (!sysparam_is_locked(param)) {
		param->flags |= SYSPARAM_FLAG_LOCK;
		params.dirty = true;
	}

	return NO_ERROR;
}

#endif // SYSPARAM_ALLOW_WRITE

#define MAX_DUMP_LEN  16

void sysparam_dump(bool show_all)
{
	printf("system parameters:\n");

	size_t total_memlen = 0;

	struct sysparam *param;
	list_for_every_entry(&params.list, param, struct sysparam, node) {
		printf("________%c %-16s : ",
				(param->flags & SYSPARAM_FLAG_LOCK) ? 'L' : '_',
				param->name);

		const uint8_t *dat = (const uint8_t *)param->data;
		uint32_t pr_len = param->datalen;

		if (!show_all) {
			if (pr_len > MAX_DUMP_LEN)
				pr_len = MAX_DUMP_LEN;
		}

		for (uint i = 0; i < pr_len; i++) {
			printf("%02x", dat[i]);
		}
		if (pr_len != param->datalen)
			printf("...\n");
		else
			printf("\n");

		total_memlen += param->memlen;
	}

	printf("total in-memory usage: %zu bytes\n", total_memlen);
}

#if WITH_LIB_CONSOLE

#include <lib/console.h>
#include <ctype.h>

static ssize_t hexstr_to_val(const char *str, uint8_t **buf)
{
	/* parse the value parameter as a hex code */
	uint8_t *hexbuffer = calloc(1, strlen(str) / 2 + 1);
	uint pos;
	for (pos = 0; str[pos] != 0; pos++) {
		uint8_t c = str[pos];

		if (!isxdigit(c)) {
			return ERR_NOT_VALID;
		}

		if (c >= '0' && c <= '9')
			c -= '0';
		else if (c >= 'a' && c <= 'f')
			c -= 'a' - 0xa;
		else if (c >= 'A' && c <= 'F')
			c -= 'A' - 0xa;

		hexbuffer[pos / 2] |= (!(pos % 2)) ? (c << 4) : c;
	}
	pos = (pos + 1) / 2; /* round down, keeping partial bytes */

	*buf = hexbuffer;
	return pos;
}

static int cmd_sysparam(int argc, const cmd_args *argv)
{
	status_t err;

	if (argc < 2) {
notenoughargs:
		printf("ERROR not enough arguments\n");
usage:
		printf("usage: %s dump\n", argv[0].str);
		printf("usage: %s list\n", argv[0].str);
		printf("usage: %s reload\n", argv[0].str);
#if SYSPARAM_ALLOW_WRITE
		printf("usage: %s add <param> <string value>\n", argv[0].str);
		printf("usage: %s addhex <param> <hex value>\n", argv[0].str);
		printf("usage: %s addlong <param>\n", argv[0].str);
		printf("usage: %s remove <param>\n", argv[0].str);
		printf("usage: %s lock <param>\n", argv[0].str);
		printf("usage: %s write\n", argv[0].str);
#endif
		printf("usage: %s length <param>\n", argv[0].str);
		printf("usage: %s read <param>\n", argv[0].str);
		return -1;
	}

	err = NO_ERROR;
	if (!strcmp(argv[1].str, "dump")) {
		sysparam_dump(true);
	} else if (!strcmp(argv[1].str, "list")) {
		struct sysparam *param;
		list_for_every_entry(&params.list, param, struct sysparam, node) {
			printf("%s\n", param->name);
		}
	} else if (!strcmp(argv[1].str, "reload")) {
		err = sysparam_reload();
#if SYSPARAM_ALLOW_WRITE
	} else if (!strcmp(argv[1].str, "add")) {
		if (argc < 4) goto notenoughargs;

		err = sysparam_add(argv[2].str, argv[3].str, strlen(argv[3].str));
	} else if (!strcmp(argv[1].str, "addhex")) {
		if (argc < 4) goto notenoughargs;

		/* parse the value parameter as a hex code */
		uint8_t *hexbuffer;

		ssize_t len = hexstr_to_val(argv[3].str, &hexbuffer);
		if (len < 0) {
			err = ERR_INVALID_ARGS;
			goto done;
		}

		err = sysparam_add(argv[2].str, hexbuffer, len);
		free(hexbuffer);
	} else if (!strcmp(argv[1].str, "addlong")) {
		if (argc < 3) goto notenoughargs;

		char *str;
		ssize_t buflen = 64;
		ssize_t len = 0;
		str = malloc(buflen + 1);
		if (!str) {
			err = ERR_NO_MEMORY;
			goto done;
		}

		for (;;) {
			int c = getchar();
			if (err < 0)
				break;
			if (c == '\r')
				continue;
			if (c == '\04') /* ^d */
				break;
			if (c == '\n')
				break;

			if (len == buflen) {
				buflen *= 2;
				char *origstr = str;
				str = realloc(str, buflen + 1);
				if (!str) {
					err = ERR_NO_MEMORY;
					free(origstr);
					goto done;
				}
			}

			str[len++] = c;
		}
		str[len] = '\0';

		/* parse the value parameter as a hex code */
		uint8_t *hexbuffer;

		len = hexstr_to_val(str, &hexbuffer);

		free(str);

		if (len < 0) {
			err = ERR_INVALID_ARGS;
			goto done;
		}

		err = sysparam_add(argv[2].str, hexbuffer, len);

		free(hexbuffer);
	} else if (!strcmp(argv[1].str, "remove")) {
		if (argc < 3) goto notenoughargs;

		err = sysparam_remove(argv[2].str);
	} else if (!strcmp(argv[1].str, "lock")) {
		if (argc < 3) goto notenoughargs;

		err = sysparam_lock(argv[2].str);
	} else if (!strcmp(argv[1].str, "write")) {
		err = sysparam_write();
	} else if (!strcmp(argv[1].str, "nuke")) {
		ssize_t err = bio_erase(params.bdev, params.offset, params.len);
		printf("erase returns %d\n", (int)err);
#endif // SYSPARAM_ALLOW_WRITE
	} else if (!strcmp(argv[1].str, "length")) {
		if (argc < 3) goto notenoughargs;
		ssize_t len = sysparam_length(argv[2].str);
		if (len >= 0) {
			printf("%zu\n", (size_t)len);
		}
		err = (len >= 0) ? NO_ERROR : len;
	} else if (!strcmp(argv[1].str, "read")) {
		if (argc < 3) goto notenoughargs;
		ssize_t len = sysparam_length(argv[2].str);
		if (len < 0) {
			err = len;
			goto done;
		}
		uint8_t *buf = malloc(len);
		if (!buf) {
			err = ERR_NO_MEMORY;
			goto done;
		}
		len = sysparam_read(argv[2].str, buf, len);
		if (len < 0) {
			err = len;
			goto done;
		}
		err = NO_ERROR;

		for (int i = 0; i < len; i++)
			printf("%02x", buf[i]);
		printf("\n");
		free(buf);
	} else {
		printf("ERROR unknown command\n");
		goto usage;
	}

done:
	/* shared error reporting */
	if (err >= NO_ERROR) {
		printf("OK\n");
	} else if (err == ERR_NO_MEMORY) {
		printf("ERROR out of memory\n");
	} else if (err == ERR_ALREADY_EXISTS) {
		printf("ERROR already exists\n");
	} else if (err == ERR_INVALID_ARGS) {
		printf("ERROR invalid argument\n");
	} else if (err == ERR_NOT_FOUND) {
		printf("ERROR not found\n");
	} else if (err == ERR_NOT_ALLOWED) {
		printf("ERROR not allowed (locked)\n");
	} else {
		printf("ERROR generic error %d\n", err);
	}

	return 0;
}

STATIC_COMMAND_START
STATIC_COMMAND("sysparam", "commands for manipulating system parameters", &cmd_sysparam)
STATIC_COMMAND_END(sysparam);

#endif // WITH_LIB_CONSOLE