libwebsockets/lib/core/libwebsockets.c

/*
 * libwebsockets - small server side websockets and web server implementation
 *
 * Copyright (C) 2010 - 2020 Andy Green <andy@warmcat.com>
 *
 * 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 "private-lib-core.h"

#ifdef LWS_HAVE_SYS_TYPES_H
#include <sys/types.h>
#endif

void
lws_ser_wu16be(uint8_t *b, uint16_t u)
{
	*b++ = (uint8_t)(u >> 8);
	*b = (uint8_t)u;
}

void
lws_ser_wu32be(uint8_t *b, uint32_t u32)
{
	*b++ = (uint8_t)(u32 >> 24);
	*b++ = (uint8_t)(u32 >> 16);
	*b++ = (uint8_t)(u32 >> 8);
	*b = (uint8_t)u32;
}

void
lws_ser_wu64be(uint8_t *b, uint64_t u64)
{
	lws_ser_wu32be(b, (uint32_t)(u64 >> 32));
	lws_ser_wu32be(b + 4, (uint32_t)u64);
}

uint16_t
lws_ser_ru16be(const uint8_t *b)
{
	return (b[0] << 8) | b[1];
}

uint32_t
lws_ser_ru32be(const uint8_t *b)
{
	return (b[0] << 24) | (b[1] << 16) | (b[2] << 8) | b[3];
}

uint64_t
lws_ser_ru64be(const uint8_t *b)
{
	return (((uint64_t)lws_ser_ru32be(b)) << 32) | lws_ser_ru32be(b + 4);
}

int
lws_vbi_encode(uint64_t value, void *buf)
{
	uint8_t *p = (uint8_t *)buf, b;

	if (value > 0xfffffff) {
		assert(0);
		return -1;
	}

	do {
		b = value & 0x7f;
		value >>= 7;
		if (value)
			*p++ = (0x80 | b);
		else
			*p++ = b;
	} while (value);

	return lws_ptr_diff(p, buf);
}

int
lws_vbi_decode(const void *buf, uint64_t *value, size_t len)
{
	const uint8_t *p = (const uint8_t *)buf, *end = p + len;
	uint64_t v = 0;
	int s = 0;

	while (p < end) {
		v |= (((uint64_t)(*p)) & 0x7f) << s;
		if (*p & 0x80) {
			*value = v;

			return lws_ptr_diff(p, buf);
		}
		s += 7;
		if (s >= 64)
			return 0;
		p++;
	}

	return 0;
}

signed char char_to_hex(const char c)
{
	if (c >= '0' && c <= '9')
		return c - '0';

	if (c >= 'a' && c <= 'f')
		return c - 'a' + 10;

	if (c >= 'A' && c <= 'F')
		return c - 'A' + 10;

	return -1;
}

int
lws_hex_to_byte_array(const char *h, uint8_t *dest, int max)
{
	uint8_t *odest = dest;

	while (max-- && *h) {
		int t = char_to_hex(*h++), t1;

		if (!*h || t < 0)
			return -1;

		t1 = char_to_hex(*h++);
		if (t1 < 0)
			return -1;

		*dest++ = (t << 4) | t1;
	}

	if (max < 0)
		return -1;

	return lws_ptr_diff(dest, odest);
}


#if !defined(LWS_PLAT_OPTEE)

#if defined(LWS_WITH_FILE_OPS)
int lws_open(const char *__file, int __oflag, ...)
{
	va_list ap;
	int n;

	va_start(ap, __oflag);
	if (((__oflag & O_CREAT) == O_CREAT)
#if defined(O_TMPFILE)
		|| ((__oflag & O_TMPFILE) == O_TMPFILE)
#endif
	)
		/* last arg is really a mode_t.  But windows... */
		n = open(__file, __oflag, va_arg(ap, uint32_t));
	else
		n = open(__file, __oflag);
	va_end(ap);

	if (n != -1 && lws_plat_apply_FD_CLOEXEC(n)) {
		close(n);

		return -1;
	}

	return n;
}
#endif
#endif

int
lws_pthread_self_to_tsi(struct lws_context *context)
{
#if LWS_MAX_SMP > 1
	pthread_t ps = pthread_self();
	struct lws_context_per_thread *pt = &context->pt[0];
	int n;

	for (n = 0; n < context->count_threads; n++) {
		if (pthread_equal(ps, pt->self))
			return n;
		pt++;
	}

	return -1;
#else
	return 0;
#endif
}

void *
lws_context_user(struct lws_context *context)
{
	return context->user_space;
}

void
lws_explicit_bzero(void *p, size_t len)
{
	volatile uint8_t *vp = p;

	while (len--)
		*vp++ = 0;
}

#if !(defined(LWS_PLAT_OPTEE) && !defined(LWS_WITH_NETWORK))

/**
 * lws_now_secs() - seconds since 1970-1-1
 *
 */
unsigned long
lws_now_secs(void)
{
	struct timeval tv;

	gettimeofday(&tv, NULL);

	return tv.tv_sec;
}

#endif

#if defined(LWS_WITH_SERVER)
const char *
lws_canonical_hostname(struct lws_context *context)
{
	return (const char *)context->canonical_hostname;
}
#endif

int
lws_get_count_threads(struct lws_context *context)
{
	return context->count_threads;
}

static const unsigned char e0f4[] = {
	0xa0 | ((2 - 1) << 2) | 1, /* e0 */
	0x80 | ((4 - 1) << 2) | 1, /* e1 */
	0x80 | ((4 - 1) << 2) | 1, /* e2 */
	0x80 | ((4 - 1) << 2) | 1, /* e3 */
	0x80 | ((4 - 1) << 2) | 1, /* e4 */
	0x80 | ((4 - 1) << 2) | 1, /* e5 */
	0x80 | ((4 - 1) << 2) | 1, /* e6 */
	0x80 | ((4 - 1) << 2) | 1, /* e7 */
	0x80 | ((4 - 1) << 2) | 1, /* e8 */
	0x80 | ((4 - 1) << 2) | 1, /* e9 */
	0x80 | ((4 - 1) << 2) | 1, /* ea */
	0x80 | ((4 - 1) << 2) | 1, /* eb */
	0x80 | ((4 - 1) << 2) | 1, /* ec */
	0x80 | ((2 - 1) << 2) | 1, /* ed */
	0x80 | ((4 - 1) << 2) | 1, /* ee */
	0x80 | ((4 - 1) << 2) | 1, /* ef */
	0x90 | ((3 - 1) << 2) | 2, /* f0 */
	0x80 | ((4 - 1) << 2) | 2, /* f1 */
	0x80 | ((4 - 1) << 2) | 2, /* f2 */
	0x80 | ((4 - 1) << 2) | 2, /* f3 */
	0x80 | ((1 - 1) << 2) | 2, /* f4 */

	0,			   /* s0 */
	0x80 | ((4 - 1) << 2) | 0, /* s2 */
	0x80 | ((4 - 1) << 2) | 1, /* s3 */
};

int
lws_check_byte_utf8(unsigned char state, unsigned char c)
{
	unsigned char s = state;

	if (!s) {
		if (c >= 0x80) {
			if (c < 0xc2 || c > 0xf4)
				return -1;
			if (c < 0xe0)
				return 0x80 | ((4 - 1) << 2);
			else
				return e0f4[c - 0xe0];
		}

		return s;
	}
	if (c < (s & 0xf0) || c >= (s & 0xf0) + 0x10 + ((s << 2) & 0x30))
		return -1;

	return e0f4[21 + (s & 3)];
}

int
lws_check_utf8(unsigned char *state, unsigned char *buf, size_t len)
{
	unsigned char s = *state;

	while (len--) {
		unsigned char c = *buf++;

		if (!s) {
			if (c >= 0x80) {
				if (c < 0xc2 || c > 0xf4)
					return 1;
				if (c < 0xe0)
					s = 0x80 | ((4 - 1) << 2);
				else
					s = e0f4[c - 0xe0];
			}
		} else {
			if (c < (s & 0xf0) ||
			    c >= (s & 0xf0) + 0x10 + ((s << 2) & 0x30))
				return 1;
			s = e0f4[21 + (s & 3)];
		}
	}

	*state = s;

	return 0;
}


char *
lws_strdup(const char *s)
{
	char *d = lws_malloc(strlen(s) + 1, "strdup");

	if (d)
		strcpy(d, s);

	return d;
}

static const char *hex = "0123456789ABCDEF";

const char *
lws_sql_purify(char *escaped, const char *string, int len)
{
	const char *p = string;
	char *q = escaped;

	while (*p && len-- > 2) {
		if (*p == '\'') {
			*q++ = '\'';
			*q++ = '\'';
			len --;
			p++;
		} else
			*q++ = *p++;
	}
	*q = '\0';

	return escaped;
}

int
lws_sql_purify_len(const char *p)
{
	int olen = 0;

	while (*p) {
		if (*p++ == '\'')
			olen++;
		olen++;
	}

	return olen;
}

const char *
lws_json_purify(char *escaped, const char *string, int len, int *in_used)
{
	const char *p = string;
	char *q = escaped;

	if (!p) {
		escaped[0] = '\0';
		return escaped;
	}

	while (*p && len-- > 6) {
		if (*p == '\t') {
			p++;
			*q++ = '\\';
			*q++ = 't';
			continue;
		}

		if (*p == '\n') {
			p++;
			*q++ = '\\';
			*q++ = 'n';
			continue;
		}

		if (*p == '\r') {
			p++;
			*q++ = '\\';
			*q++ = 'r';
			continue;
		}

		if (*p == '\"' || *p == '\\' || *p < 0x20) {
			*q++ = '\\';
			*q++ = 'u';
			*q++ = '0';
			*q++ = '0';
			*q++ = hex[((*p) >> 4) & 15];
			*q++ = hex[(*p) & 15];
			len -= 5;
			p++;
		} else
			*q++ = *p++;
	}
	*q = '\0';

	if (in_used)
		*in_used = lws_ptr_diff(p, string);

	return escaped;
}

int
lws_json_purify_len(const char *string)
{
	int len = 0;
	const char *p = string;

	while (*p) {
		if (*p == '\t' || *p == '\n' || *p == '\r') {
			p++;
			len += 2;
			continue;
		}

		if (*p == '\"' || *p == '\\' || *p < 0x20) {
			len += 6;
			p++;
			continue;
		}
		p++;
		len++;
	}

	return len;
}

void
lws_filename_purify_inplace(char *filename)
{
	while (*filename) {

		if (*filename == '.' && filename[1] == '.') {
			*filename = '_';
			filename[1] = '_';
		}

		if (*filename == ':' ||
		    *filename == '\\' ||
		    *filename == '$' ||
		    *filename == '%')
			*filename = '_';

		filename++;
	}
}

const char *
lws_urlencode(char *escaped, const char *string, int len)
{
	const char *p = string;
	char *q = escaped;

	while (*p && len-- > 3) {
		if (*p == ' ') {
			*q++ = '+';
			p++;
			continue;
		}
		if ((*p >= '0' && *p <= '9') ||
		    (*p >= 'A' && *p <= 'Z') ||
		    (*p >= 'a' && *p <= 'z')) {
			*q++ = *p++;
			continue;
		}
		*q++ = '%';
		*q++ = hex[(*p >> 4) & 0xf];
		*q++ = hex[*p & 0xf];

		len -= 2;
		p++;
	}
	*q = '\0';

	return escaped;
}

int
lws_urldecode(char *string, const char *escaped, int len)
{
	int state = 0, n;
	char sum = 0;

	while (*escaped && len) {
		switch (state) {
		case 0:
			if (*escaped == '%') {
				state++;
				escaped++;
				continue;
			}
			if (*escaped == '+') {
				escaped++;
				*string++ = ' ';
				len--;
				continue;
			}
			*string++ = *escaped++;
			len--;
			break;
		case 1:
			n = char_to_hex(*escaped);
			if (n < 0)
				return -1;
			escaped++;
			sum = n << 4;
			state++;
			break;

		case 2:
			n = char_to_hex(*escaped);
			if (n < 0)
				return -1;
			escaped++;
			*string++ = sum | n;
			len--;
			state = 0;
			break;
		}

	}
	*string = '\0';

	return 0;
}

int
lws_finalize_startup(struct lws_context *context)
{
	if (lws_check_opt(context->options, LWS_SERVER_OPTION_EXPLICIT_VHOSTS))
		if (lws_plat_drop_app_privileges(context, 1))
			return 1;

	return 0;
}

void
lws_get_effective_uid_gid(struct lws_context *context, int *uid, int *gid)
{
	*uid = context->uid;
	*gid = context->gid;
}

int
lws_snprintf(char *str, size_t size, const char *format, ...)
{
	va_list ap;
	int n;

	if (!size)
		return 0;

	va_start(ap, format);
	n = vsnprintf(str, size, format, ap);
	va_end(ap);

	if (n >= (int)size)
		return (int)size;

	return n;
}

char *
lws_strncpy(char *dest, const char *src, size_t size)
{
	strncpy(dest, src, size - 1);
	dest[size - 1] = '\0';

	return dest;
}

int
lws_timingsafe_bcmp(const void *a, const void *b, uint32_t len)
{
	const uint8_t *pa = a, *pb = b;
	uint8_t sum = 0;

	while (len--)
		sum |= (*pa++ ^ *pb++);

	return sum;
}


typedef enum {
	LWS_TOKZS_LEADING_WHITESPACE,
	LWS_TOKZS_QUOTED_STRING,
	LWS_TOKZS_TOKEN,
	LWS_TOKZS_TOKEN_POST_TERMINAL
} lws_tokenize_state;

lws_tokenize_elem
lws_tokenize(struct lws_tokenize *ts)
{
	const char *rfc7230_delims = "(),/:;<=>?@[\\]{}";
	lws_tokenize_state state = LWS_TOKZS_LEADING_WHITESPACE;
	char c, flo = 0, d_minus = '-', d_dot = '.', s_minus = '\0',
	     s_dot = '\0', skipping = 0;
	signed char num = (ts->flags & LWS_TOKENIZE_F_NO_INTEGERS) ? 0 : -1;
	int utf8 = 0;

	/* for speed, compute the effect of the flags outside the loop */

	if (ts->flags & LWS_TOKENIZE_F_MINUS_NONTERM) {
		d_minus = '\0';
		s_minus = '-';
	}
	if (ts->flags & LWS_TOKENIZE_F_DOT_NONTERM) {
		d_dot = '\0';
		s_dot = '.';
	}

	ts->token = NULL;
	ts->token_len = 0;

	while (ts->len) {
		c = *ts->start++;
		ts->len--;

		utf8 = lws_check_byte_utf8((unsigned char)utf8, c);
		if (utf8 < 0)
			return LWS_TOKZE_ERR_BROKEN_UTF8;

		if (!c)
			break;

		if (skipping) {
			if (c != '\r' && c != '\n')
				continue;
			else
				skipping = 0;
		}

		/* comment */

		if (ts->flags & LWS_TOKENIZE_F_HASH_COMMENT &&
		    state != LWS_TOKZS_QUOTED_STRING &&
		    c == '#') {
			skipping = 1;
			continue;
		}

		/* whitespace */

		if (c == ' ' || c == '\t' || c == '\n' || c == '\r' ||
		    c == '\f') {
			switch (state) {
			case LWS_TOKZS_LEADING_WHITESPACE:
			case LWS_TOKZS_TOKEN_POST_TERMINAL:
				continue;
			case LWS_TOKZS_QUOTED_STRING:
				ts->token_len++;
				continue;
			case LWS_TOKZS_TOKEN:
				/* we want to scan forward to look for = */

				state = LWS_TOKZS_TOKEN_POST_TERMINAL;
				continue;
			}
		}

		/* quoted string */

		if (c == '\"') {
			if (state == LWS_TOKZS_QUOTED_STRING)
				return LWS_TOKZE_QUOTED_STRING;

			/* starting a quoted string */

			if (ts->flags & LWS_TOKENIZE_F_COMMA_SEP_LIST) {
				if (ts->delim == LWSTZ_DT_NEED_DELIM)
					return LWS_TOKZE_ERR_COMMA_LIST;
				ts->delim = LWSTZ_DT_NEED_DELIM;
			}

			state = LWS_TOKZS_QUOTED_STRING;
			ts->token = ts->start;
			ts->token_len = 0;

			continue;
		}

		/* token= aggregation */

		if (c == '=' && (state == LWS_TOKZS_TOKEN_POST_TERMINAL ||
				 state == LWS_TOKZS_TOKEN)) {
			if (num == 1)
				return LWS_TOKZE_ERR_NUM_ON_LHS;
			/* swallow the = */
			return LWS_TOKZE_TOKEN_NAME_EQUALS;
		}

		/* optional token: aggregation */

		if ((ts->flags & LWS_TOKENIZE_F_AGG_COLON) && c == ':' &&
		    (state == LWS_TOKZS_TOKEN_POST_TERMINAL ||
		     state == LWS_TOKZS_TOKEN))
			/* swallow the : */
			return LWS_TOKZE_TOKEN_NAME_COLON;

		/* aggregate . in a number as a float */

		if (c == '.' && !(ts->flags & LWS_TOKENIZE_F_NO_FLOATS) &&
		    state == LWS_TOKZS_TOKEN && num == 1) {
			if (flo)
				return LWS_TOKZE_ERR_MALFORMED_FLOAT;
			flo = 1;
			ts->token_len++;
			continue;
		}

		/*
		 * Delimiter... by default anything that:
		 *
		 *  - isn't matched earlier, or
		 *  - is [A-Z, a-z, 0-9, _], and
		 *  - is not a partial utf8 char
		 *
		 * is a "delimiter", it marks the end of a token and is itself
		 * reported as a single LWS_TOKZE_DELIMITER each time.
		 *
		 * However with LWS_TOKENIZE_F_RFC7230_DELIMS flag, tokens may
		 * contain any noncontrol character that isn't defined in
		 * rfc7230_delims, and only characters listed there are treated
		 * as delimiters.
		 */

		if (!utf8 &&
		     ((ts->flags & LWS_TOKENIZE_F_RFC7230_DELIMS &&
		     strchr(rfc7230_delims, c) && c > 32) ||
		    ((!(ts->flags & LWS_TOKENIZE_F_RFC7230_DELIMS) &&
		     (c < '0' || c > '9') && (c < 'A' || c > 'Z') &&
		     (c < 'a' || c > 'z') && c != '_') &&
		     c != s_minus && c != s_dot) ||
		    c == d_minus || c == d_dot
		    ) &&
		    !((ts->flags & LWS_TOKENIZE_F_SLASH_NONTERM) && c == '/')) {
			switch (state) {
			case LWS_TOKZS_LEADING_WHITESPACE:
				if (ts->flags & LWS_TOKENIZE_F_COMMA_SEP_LIST) {
					if (c != ',' ||
					    ts->delim != LWSTZ_DT_NEED_DELIM)
						return LWS_TOKZE_ERR_COMMA_LIST;
					ts->delim = LWSTZ_DT_NEED_NEXT_CONTENT;
				}

				ts->token = ts->start - 1;
				ts->token_len = 1;
				return LWS_TOKZE_DELIMITER;

			case LWS_TOKZS_QUOTED_STRING:
				ts->token_len++;
				continue;

			case LWS_TOKZS_TOKEN_POST_TERMINAL:
			case LWS_TOKZS_TOKEN:
				/* report the delimiter next time */
				ts->start--;
				ts->len++;
				goto token_or_numeric;
			}
		}

		/* anything that's not whitespace or delimiter is payload */

		switch (state) {
		case LWS_TOKZS_LEADING_WHITESPACE:

			if (ts->flags & LWS_TOKENIZE_F_COMMA_SEP_LIST) {
				if (ts->delim == LWSTZ_DT_NEED_DELIM)
					return LWS_TOKZE_ERR_COMMA_LIST;
				ts->delim = LWSTZ_DT_NEED_DELIM;
			}

			state = LWS_TOKZS_TOKEN;
			ts->token = ts->start - 1;
			ts->token_len = 1;
			goto checknum;

		case LWS_TOKZS_QUOTED_STRING:
		case LWS_TOKZS_TOKEN:
			ts->token_len++;
checknum:
			if (!(ts->flags & LWS_TOKENIZE_F_NO_INTEGERS)) {
				if (c < '0' || c > '9')
					num = 0;
				else
					if (num < 0)
						num = 1;
			}
			continue;

		case LWS_TOKZS_TOKEN_POST_TERMINAL:
			/* report the new token next time */
			ts->start--;
			ts->len++;
			goto token_or_numeric;
		}
	}

	/* we ran out of content */

	if (utf8) /* ended partway through a multibyte char */
		return LWS_TOKZE_ERR_BROKEN_UTF8;

	if (state == LWS_TOKZS_QUOTED_STRING)
		return LWS_TOKZE_ERR_UNTERM_STRING;

	if (state != LWS_TOKZS_TOKEN_POST_TERMINAL &&
	    state != LWS_TOKZS_TOKEN) {
		if ((ts->flags & LWS_TOKENIZE_F_COMMA_SEP_LIST) &&
		     ts->delim == LWSTZ_DT_NEED_NEXT_CONTENT)
			return LWS_TOKZE_ERR_COMMA_LIST;

		return LWS_TOKZE_ENDED;
	}

	/* report the pending token */

token_or_numeric:

	if (num != 1)
		return LWS_TOKZE_TOKEN;
	if (flo)
		return LWS_TOKZE_FLOAT;

	return LWS_TOKZE_INTEGER;
}


int
lws_tokenize_cstr(struct lws_tokenize *ts, char *str, size_t max)
{
	if (ts->token_len + 1 >= max)
		return 1;

	memcpy(str, ts->token, ts->token_len);
	str[ts->token_len] = '\0';

	return 0;
}

void
lws_tokenize_init(struct lws_tokenize *ts, const char *start, int flags)
{
	ts->start = start;
	ts->len = 0x7fffffff;
	ts->flags = flags;
	ts->delim = LWSTZ_DT_NEED_FIRST_CONTENT;
}


typedef enum {
	LWS_EXPS_LITERAL,
	LWS_EXPS_OPEN_OR_LIT,
	LWS_EXPS_NAME_OR_CLOSE,
	LWS_EXPS_DRAIN,
} lws_strexp_state;

void
lws_strexp_init(lws_strexp_t *exp, void *priv, lws_strexp_expand_cb cb,
		 char *out, size_t olen)
{
	memset(exp, 0, sizeof(*exp));
	exp->cb = cb;
	exp->out = out;
	exp->olen = olen;
	exp->state = LWS_EXPS_LITERAL;
	exp->priv = priv;
}

void
lws_strexp_reset_out(lws_strexp_t *exp, char *out, size_t olen)
{
	exp->out = out;
	exp->olen = olen;
	exp->pos = 0;
}

int
lws_strexp_expand(lws_strexp_t *exp, const char *in, size_t len,
		  size_t *pused_in, size_t *pused_out)
{
	size_t used = 0;
	int n;

	while (used < len) {

		switch (exp->state) {
		case LWS_EXPS_LITERAL:
			if (*in == '$') {
				exp->state = LWS_EXPS_OPEN_OR_LIT;
				break;
			}

			exp->out[exp->pos++] = *in;
			if (exp->olen - exp->pos < 1) {
				*pused_in = used + 1;
				*pused_out = exp->pos;
				return LSTRX_FILLED_OUT;
			}
			break;

		case LWS_EXPS_OPEN_OR_LIT:
			if (*in == '{') {
				exp->state = LWS_EXPS_NAME_OR_CLOSE;
				exp->name_pos = 0;
				exp->exp_ofs = 0;
				break;
			}
			/* treat as a literal */
			if (exp->olen - exp->pos < 3)
				return -1;

			exp->out[exp->pos++] = '$';
			exp->out[exp->pos++] = *in;
			if (*in != '$')
				exp->state = LWS_EXPS_LITERAL;
			break;

		case LWS_EXPS_NAME_OR_CLOSE:
			if (*in == '}') {
				exp->name[exp->name_pos] = '\0';
				exp->state = LWS_EXPS_DRAIN;
				goto drain;
			}
			if (exp->name_pos >= sizeof(exp->name) - 1)
				return LSTRX_FATAL_NAME_TOO_LONG;

			exp->name[exp->name_pos++] = *in;
			break;

		case LWS_EXPS_DRAIN:
drain:
			*pused_in = used;
			n = exp->cb(exp->priv, exp->name, exp->out, &exp->pos,
				    exp->olen, &exp->exp_ofs);
			*pused_out = exp->pos;
			if (n == LSTRX_FILLED_OUT ||
			    n == LSTRX_FATAL_NAME_UNKNOWN)
				return n;

			exp->state = LWS_EXPS_LITERAL;
			break;
		}

		used++;
		in++;
	}

	exp->out[exp->pos] = '\0';
	*pused_in = used;
	*pused_out = exp->pos;

	return LSTRX_DONE;
}


#if LWS_MAX_SMP > 1

void
lws_mutex_refcount_init(struct lws_mutex_refcount *mr)
{
	pthread_mutex_init(&mr->lock, NULL);
	mr->last_lock_reason = NULL;
	mr->lock_depth = 0;
	mr->metadata = 0;
	mr->lock_owner = 0;
}

void
lws_mutex_refcount_destroy(struct lws_mutex_refcount *mr)
{
	pthread_mutex_destroy(&mr->lock);
}

void
lws_mutex_refcount_lock(struct lws_mutex_refcount *mr, const char *reason)
{
	/* if true, this sequence is atomic because our thread has the lock
	 *
	 *  - if true, only guy who can race to make it untrue is our thread,
	 *    and we are here.
	 *
	 *  - if false, only guy who could race to make it true is our thread,
	 *    and we are here
	 *
	 *  - it can be false and change to a different tid that is also false
	 */
	if (mr->lock_owner == pthread_self()) {
		/* atomic because we only change it if we own the lock */
		mr->lock_depth++;
		return;
	}

	pthread_mutex_lock(&mr->lock);
	/* atomic because only we can have the lock */
	mr->last_lock_reason = reason;
	mr->lock_owner = pthread_self();
	mr->lock_depth = 1;
	//lwsl_notice("tid %d: lock %s\n", mr->tid, reason);
}

void
lws_mutex_refcount_unlock(struct lws_mutex_refcount *mr)
{
	if (--mr->lock_depth)
		/* atomic because only thread that has the lock can unlock */
		return;

	mr->last_lock_reason = "free";
	mr->lock_owner = 0;
	//lwsl_notice("tid %d: unlock %s\n", mr->tid, mr->last_lock_reason);
	pthread_mutex_unlock(&mr->lock);
}

#endif /* SMP */


const char *
lws_cmdline_option(int argc, const char **argv, const char *val)
{
	int n = (int)strlen(val), c = argc;

	while (--c > 0) {

		if (!strncmp(argv[c], val, n)) {
			if (!*(argv[c] + n) && c < argc - 1) {
				/* coverity treats unchecked argv as "tainted" */
				if (!argv[c + 1] || strlen(argv[c + 1]) > 1024)
					return NULL;
				return argv[c + 1];
			}

			if (argv[c][n] == '=')
				return &argv[c][n + 1];
			return argv[c] + n;
		}
	}

	return NULL;
}

static const char * const builtins[] = {
	"-d",
	"--udp-tx-loss",
	"--udp-rx-loss"
};

void
lws_cmdline_option_handle_builtin(int argc, const char **argv,
				  struct lws_context_creation_info *info)
{
	const char *p;
	int n, m, logs = LLL_USER | LLL_ERR | LLL_WARN | LLL_NOTICE;

	for (n = 0; n < (int)LWS_ARRAY_SIZE(builtins); n++) {
		p = lws_cmdline_option(argc, argv, builtins[n]);
		if (!p)
			continue;

		m = atoi(p);

		switch (n) {
		case 0:
			logs = m;
			break;
		case 1:
			info->udp_loss_sim_tx_pc = m;
			break;
		case 2:
			info->udp_loss_sim_rx_pc = m;
			break;
		}
	}

	lws_set_log_level(logs, NULL);
}


const lws_humanize_unit_t humanize_schema_si[] = {
	{ "Pi ", LWS_PI }, { "Ti ", LWS_TI }, { "Gi ", LWS_GI },
	{ "Mi ", LWS_MI }, { "Ki ", LWS_KI }, { "   ", 1 },
	{ NULL, 0 }
};
const lws_humanize_unit_t humanize_schema_si_bytes[] = {
	{ "PiB", LWS_PI }, { "TiB", LWS_TI }, { "GiB", LWS_GI },
	{ "MiB", LWS_MI }, { "KiB", LWS_KI }, { "B  ", 1 },
	{ NULL, 0 }
};
const lws_humanize_unit_t humanize_schema_us[] = {
	{ "y  ",  (uint64_t)365 * 24 * 3600 * LWS_US_PER_SEC },
	{ "d  ",  (uint64_t)24 * 3600 * LWS_US_PER_SEC },
	{ "hr ", (uint64_t)3600 * LWS_US_PER_SEC },
	{ "min", 60 * LWS_US_PER_SEC },
	{ "s  ", LWS_US_PER_SEC },
	{ "ms ", LWS_US_PER_MS },
	{ "us ", 1 },
	{ NULL, 0 }
};

static int
decim(char *r, uint64_t v, char chars, char leading)
{
	int n = chars - 1;
	uint64_t q = 1;

	r += n;

	while (n >= 0) {
		if (v / q)
			*r-- = '0' + ((v / q) % 10);
		else
			*r-- = leading ? '0' : ' ';
		q = q * 10;
		n--;
	}

	if (v / q)
		/* the number is bigger than the allowed chars! */
		r[1] = '!';

	return chars;
}

int
lws_humanize(char *p, int len, uint64_t v, const lws_humanize_unit_t *schema)
{
	char *end = p + len;

	do {
		if (v >= schema->factor || schema->factor == 1) {
			if (schema->factor == 1) {
				*p++ = ' ';
				p += decim(p, v, 4, 0);
				return lws_snprintf(p, lws_ptr_diff(end, p),
						    "%s    ", schema->name);
			}

			*p++ = ' ';
			p += decim(p, v / schema->factor, 4, 0);
			*p++ = '.';
			p += decim(p, (v % schema->factor) /
					(schema->factor / 1000), 3, 1);

			return lws_snprintf(p, lws_ptr_diff(end, p),
					    "%s", schema->name);
		}
		schema++;
	} while (schema->name);

	assert(0);
	strncpy(p, "unknown value", len);

	return 0;
}