bfgminer/util.c

/*
 * Copyright 2011-2013 Con Kolivas
 * Copyright 2011-2013 Luke Dashjr
 * Copyright 2010 Jeff Garzik
 * Copyright 2012 Giel van Schijndel
 * Copyright 2012 Gavin Andresen
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the Free
 * Software Foundation; either version 3 of the License, or (at your option)
 * any later version.  See COPYING for more details.
 */

#include "config.h"

#ifdef WIN32
#define FD_SETSIZE 4096
#endif

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>
#include <stdarg.h>
#include <string.h>
#include <pthread.h>
#include <jansson.h>
#include <curl/curl.h>
#include <time.h>
#include <errno.h>
#include <unistd.h>
#include <sys/types.h>
#ifdef HAVE_SYS_PRCTL_H
# include <sys/prctl.h>
#endif
#if defined(__FreeBSD__) || defined(__OpenBSD__)
# include <pthread_np.h>
#endif
#ifndef WIN32
# ifdef __linux
#  include <sys/prctl.h>
# endif
# include <sys/socket.h>
# include <netinet/in.h>
# include <netinet/tcp.h>
# include <netdb.h>
#else
# include <winsock2.h>
# include <mstcpip.h>
# include <ws2tcpip.h>
#endif

#include "miner.h"
#include "elist.h"
#include "compat.h"
#include "util.h"

bool successful_connect = false;
struct timeval nettime;

struct data_buffer {
	void		*buf;
	size_t		len;
	curl_socket_t	*idlemarker;
};

struct upload_buffer {
	const void	*buf;
	size_t		len;
};

struct header_info {
	char		*lp_path;
	int		rolltime;
	char		*reason;
	char		*stratum_url;
	bool		hadrolltime;
	bool		canroll;
	bool		hadexpire;
};

struct tq_ent {
	void			*data;
	struct list_head	q_node;
};

static void databuf_free(struct data_buffer *db)
{
	if (!db)
		return;

	free(db->buf);
#ifdef DEBUG_DATABUF
	applog(LOG_DEBUG, "databuf_free(%p)", db->buf);
#endif

	memset(db, 0, sizeof(*db));
}

// aka data_buffer_write
static size_t all_data_cb(const void *ptr, size_t size, size_t nmemb,
			  void *user_data)
{
	struct data_buffer *db = user_data;
	size_t oldlen, newlen;

	oldlen = db->len;
	if (unlikely(nmemb == 0 || size == 0 || oldlen >= SIZE_MAX - size))
		return 0;
	if (unlikely(nmemb > (SIZE_MAX - oldlen) / size))
		nmemb = (SIZE_MAX - oldlen) / size;

	size_t len = size * nmemb;
	void *newmem;
	static const unsigned char zero = 0;

	if (db->idlemarker) {
		const unsigned char *cptr = ptr;
		for (size_t i = 0; i < len; ++i)
			if (!(isspace(cptr[i]) || cptr[i] == '{')) {
				*db->idlemarker = CURL_SOCKET_BAD;
				db->idlemarker = NULL;
				break;
			}
	}

	newlen = oldlen + len;

	newmem = realloc(db->buf, newlen + 1);
#ifdef DEBUG_DATABUF
	applog(LOG_DEBUG, "data_buffer_write realloc(%p, %lu) => %p", db->buf, (long unsigned)(newlen + 1), newmem);
#endif
	if (!newmem)
		return 0;

	db->buf = newmem;
	db->len = newlen;
	memcpy(db->buf + oldlen, ptr, len);
	memcpy(db->buf + newlen, &zero, 1);	/* null terminate */

	return nmemb;
}

static size_t upload_data_cb(void *ptr, size_t size, size_t nmemb,
			     void *user_data)
{
	struct upload_buffer *ub = user_data;
	unsigned int len = size * nmemb;

	if (len > ub->len)
		len = ub->len;

	if (len) {
		memcpy(ptr, ub->buf, len);
		ub->buf += len;
		ub->len -= len;
	}

	return len;
}

static size_t resp_hdr_cb(void *ptr, size_t size, size_t nmemb, void *user_data)
{
	struct header_info *hi = user_data;
	size_t remlen, slen, ptrlen = size * nmemb;
	char *rem, *val = NULL, *key = NULL;
	void *tmp;

	val = calloc(1, ptrlen);
	key = calloc(1, ptrlen);
	if (!key || !val)
		goto out;

	tmp = memchr(ptr, ':', ptrlen);
	if (!tmp || (tmp == ptr))	/* skip empty keys / blanks */
		goto out;
	slen = tmp - ptr;
	if ((slen + 1) == ptrlen)	/* skip key w/ no value */
		goto out;
	memcpy(key, ptr, slen);		/* store & nul term key */
	key[slen] = 0;

	rem = ptr + slen + 1;		/* trim value's leading whitespace */
	remlen = ptrlen - slen - 1;
	while ((remlen > 0) && (isspace(*rem))) {
		remlen--;
		rem++;
	}

	memcpy(val, rem, remlen);	/* store value, trim trailing ws */
	val[remlen] = 0;
	while ((*val) && (isspace(val[strlen(val) - 1])))
		val[strlen(val) - 1] = 0;

	if (!*val)			/* skip blank value */
		goto out;

	if (opt_protocol)
		applog(LOG_DEBUG, "HTTP hdr(%s): %s", key, val);

	if (!strcasecmp("X-Roll-Ntime", key)) {
		hi->hadrolltime = true;
		if (!strncasecmp("N", val, 1))
			applog(LOG_DEBUG, "X-Roll-Ntime: N found");
		else {
			hi->canroll = true;

			/* Check to see if expire= is supported and if not, set
			 * the rolltime to the default scantime */
			if (strlen(val) > 7 && !strncasecmp("expire=", val, 7)) {
				sscanf(val + 7, "%d", &hi->rolltime);
				hi->hadexpire = true;
			} else
				hi->rolltime = opt_scantime;
			applog(LOG_DEBUG, "X-Roll-Ntime expiry set to %d", hi->rolltime);
		}
	}

	if (!strcasecmp("X-Long-Polling", key)) {
		hi->lp_path = val;	/* steal memory reference */
		val = NULL;
	}

	if (!strcasecmp("X-Reject-Reason", key)) {
		hi->reason = val;	/* steal memory reference */
		val = NULL;
	}

	if (!strcasecmp("X-Stratum", key)) {
		hi->stratum_url = val;
		val = NULL;
	}

out:
	free(key);
	free(val);
	return ptrlen;
}

static int keep_sockalive(SOCKETTYPE fd)
{
	const int tcp_keepidle = 60;
	const int tcp_keepintvl = 60;
	const int keepalive = 1;
	int ret = 0;


#ifndef WIN32
	const int tcp_keepcnt = 5;

	if (unlikely(setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, &keepalive, sizeof(keepalive))))
		ret = 1;

# ifdef __linux

	if (unlikely(setsockopt(fd, SOL_TCP, TCP_KEEPCNT, &tcp_keepcnt, sizeof(tcp_keepcnt))))
		ret = 1;

	if (unlikely(setsockopt(fd, SOL_TCP, TCP_KEEPIDLE, &tcp_keepidle, sizeof(tcp_keepidle))))
		ret = 1;

	if (unlikely(setsockopt(fd, SOL_TCP, TCP_KEEPINTVL, &tcp_keepintvl, sizeof(tcp_keepintvl))))
		ret = 1;
# endif /* __linux */
# ifdef __APPLE_CC__

	if (unlikely(setsockopt(fd, IPPROTO_TCP, TCP_KEEPALIVE, &tcp_keepintvl, sizeof(tcp_keepintvl))))
		ret = 1;

# endif /* __APPLE_CC__ */

#else /* WIN32 */

	const int zero = 0;
	struct tcp_keepalive vals;
	vals.onoff = 1;
	vals.keepalivetime = tcp_keepidle * 1000;
	vals.keepaliveinterval = tcp_keepintvl * 1000;

	DWORD outputBytes;

	if (unlikely(setsockopt(fd, SOL_SOCKET, SO_KEEPALIVE, (const char *)&keepalive, sizeof(keepalive))))
		ret = 1;

	if (unlikely(WSAIoctl(fd, SIO_KEEPALIVE_VALS, &vals, sizeof(vals), NULL, 0, &outputBytes, NULL, NULL)))
		ret = 1;

	/* Windows happily submits indefinitely to the send buffer blissfully
	 * unaware nothing is getting there without gracefully failing unless
	 * we disable the send buffer */
	if (unlikely(setsockopt(fd, SOL_SOCKET, SO_SNDBUF, (const char *)&zero, sizeof(zero))))
		ret = 1;
#endif /* WIN32 */

	return ret;
}

int json_rpc_call_sockopt_cb(void __maybe_unused *userdata, curl_socket_t fd,
			     curlsocktype __maybe_unused purpose)
{
	return keep_sockalive(fd);
}

static void last_nettime(struct timeval *last)
{
	rd_lock(&netacc_lock);
	last->tv_sec = nettime.tv_sec;
	last->tv_usec = nettime.tv_usec;
	rd_unlock(&netacc_lock);
}

static void set_nettime(void)
{
	wr_lock(&netacc_lock);
	gettimeofday(&nettime, NULL);
	wr_unlock(&netacc_lock);
}

static int curl_debug_cb(__maybe_unused CURL *handle, curl_infotype type,
			 char *data, size_t size,
			 void *userdata)
{
	struct pool *pool = (struct pool *)userdata;

	switch(type) {
		case CURLINFO_HEADER_IN:
		case CURLINFO_DATA_IN:
		case CURLINFO_SSL_DATA_IN:
			pool->cgminer_pool_stats.bytes_received += size;
			total_bytes_xfer += size;
			pool->cgminer_pool_stats.net_bytes_received += size;
			break;
		case CURLINFO_HEADER_OUT:
		case CURLINFO_DATA_OUT:
		case CURLINFO_SSL_DATA_OUT:
			pool->cgminer_pool_stats.bytes_sent += size;
			total_bytes_xfer += size;
			pool->cgminer_pool_stats.net_bytes_sent += size;
			break;
		case CURLINFO_TEXT:
		{
			if (!opt_protocol)
				break;
			// data is not null-terminated, so we need to copy and terminate it for applog
			char datacp[size + 1];
			memcpy(datacp, data, size);
			while (isspace(datacp[size-1]))
				--size;
			datacp[size] = '\0';
			applog(LOG_DEBUG, "Pool %u: %s", pool->pool_no, datacp);
			break;
		}
		default:
			break;
	}
	return 0;
}

struct json_rpc_call_state {
	struct data_buffer all_data;
	struct header_info hi;
	void *priv;
	char curl_err_str[CURL_ERROR_SIZE];
	struct curl_slist *headers;
	struct upload_buffer upload_data;
	struct pool *pool;
};

void json_rpc_call_async(CURL *curl, const char *url,
		      const char *userpass, const char *rpc_req,
		      bool longpoll,
		      struct pool *pool, bool share,
		      void *priv)
{
	struct json_rpc_call_state *state = malloc(sizeof(struct json_rpc_call_state));
	*state = (struct json_rpc_call_state){
		.priv = priv,
		.pool = pool,
	};
	long timeout = longpoll ? (60 * 60) : 60;
	char len_hdr[64], user_agent_hdr[128];
	struct curl_slist *headers = NULL;

	if (longpoll)
		state->all_data.idlemarker = &pool->lp_socket;

	/* it is assumed that 'curl' is freshly [re]initialized at this pt */

	curl_easy_setopt(curl, CURLOPT_PRIVATE, state);
	curl_easy_setopt(curl, CURLOPT_TIMEOUT, timeout);

	/* We use DEBUGFUNCTION to count bytes sent/received, and verbose is needed
	 * to enable it */
	curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, curl_debug_cb);
	curl_easy_setopt(curl, CURLOPT_DEBUGDATA, (void *)pool);
	curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);

	curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);
	curl_easy_setopt(curl, CURLOPT_URL, url);
	curl_easy_setopt(curl, CURLOPT_ENCODING, "");
	curl_easy_setopt(curl, CURLOPT_FAILONERROR, 1);

	/* Shares are staggered already and delays in submission can be costly
	 * so do not delay them */
	if (!opt_delaynet || share)
		curl_easy_setopt(curl, CURLOPT_TCP_NODELAY, 1);
	curl_easy_setopt(curl, CURLOPT_WRITEFUNCTION, all_data_cb);
	curl_easy_setopt(curl, CURLOPT_WRITEDATA, &state->all_data);
	curl_easy_setopt(curl, CURLOPT_READFUNCTION, upload_data_cb);
	curl_easy_setopt(curl, CURLOPT_READDATA, &state->upload_data);
	curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, &state->curl_err_str[0]);
	curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1);
	curl_easy_setopt(curl, CURLOPT_HEADERFUNCTION, resp_hdr_cb);
	curl_easy_setopt(curl, CURLOPT_HEADERDATA, &state->hi);

	curl_easy_setopt(curl, CURLOPT_USE_SSL, CURLUSESSL_TRY);
	if (pool->rpc_proxy) {
		curl_easy_setopt(curl, CURLOPT_PROXY, pool->rpc_proxy);
	} else if (opt_socks_proxy) {
		curl_easy_setopt(curl, CURLOPT_PROXY, opt_socks_proxy);
		curl_easy_setopt(curl, CURLOPT_PROXYTYPE, CURLPROXY_SOCKS4);
	}
	if (userpass) {
		curl_easy_setopt(curl, CURLOPT_USERPWD, userpass);
		curl_easy_setopt(curl, CURLOPT_HTTPAUTH, CURLAUTH_BASIC);
	}
	if (longpoll)
		curl_easy_setopt(curl, CURLOPT_SOCKOPTFUNCTION, json_rpc_call_sockopt_cb);
	curl_easy_setopt(curl, CURLOPT_POST, 1);

	if (opt_protocol)
		applog(LOG_DEBUG, "JSON protocol request:\n%s", rpc_req);

	state->upload_data.buf = rpc_req;
	state->upload_data.len = strlen(rpc_req);
	sprintf(len_hdr, "Content-Length: %lu",
		(unsigned long) state->upload_data.len);
	sprintf(user_agent_hdr, "User-Agent: %s", PACKAGE_STRING);

	headers = curl_slist_append(headers,
		"Content-type: application/json");
	headers = curl_slist_append(headers,
		"X-Mining-Extensions: longpoll midstate rollntime submitold");

	if (longpoll)
		headers = curl_slist_append(headers,
			"X-Minimum-Wait: 0");

	if (likely(global_hashrate)) {
		char ghashrate[255];

		sprintf(ghashrate, "X-Mining-Hashrate: %"PRIu64, (uint64_t)global_hashrate);
		headers = curl_slist_append(headers, ghashrate);
	}

	headers = curl_slist_append(headers, len_hdr);
	headers = curl_slist_append(headers, user_agent_hdr);
	headers = curl_slist_append(headers, "Expect:"); /* disable Expect hdr*/

	curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
	state->headers = headers;

	if (opt_delaynet) {
		/* Don't delay share submission, but still track the nettime */
		if (!share) {
			long long now_msecs, last_msecs;
			struct timeval now, last;

			gettimeofday(&now, NULL);
			last_nettime(&last);
			now_msecs = (long long)now.tv_sec * 1000;
			now_msecs += now.tv_usec / 1000;
			last_msecs = (long long)last.tv_sec * 1000;
			last_msecs += last.tv_usec / 1000;
			if (now_msecs > last_msecs && now_msecs - last_msecs < 250) {
				struct timespec rgtp;

				rgtp.tv_sec = 0;
				rgtp.tv_nsec = (250 - (now_msecs - last_msecs)) * 1000000;
				nanosleep(&rgtp, NULL);
			}
		}
		set_nettime();
	}
}

json_t *json_rpc_call_completed(CURL *curl, int rc, bool probe, int *rolltime, void *out_priv)
{
	struct json_rpc_call_state *state;
	if (curl_easy_getinfo(curl, CURLINFO_PRIVATE, &state) != CURLE_OK) {
		applog(LOG_ERR, "Failed to get private curl data");
		if (out_priv)
			*(void**)out_priv = NULL;
		goto err_out;
	}
	if (out_priv)
		*(void**)out_priv = state->priv;

	json_t *val, *err_val, *res_val;
	json_error_t err;
	struct pool *pool = state->pool;
	bool probing = probe && !pool->probed;

	if (rc) {
		applog(LOG_INFO, "HTTP request failed: %s", state->curl_err_str);
		goto err_out;
	}

	if (!state->all_data.buf) {
		applog(LOG_DEBUG, "Empty data received in json_rpc_call.");
		goto err_out;
	}

	pool->cgminer_pool_stats.times_sent++;
	pool->cgminer_pool_stats.times_received++;

	if (probing) {
		pool->probed = true;
		/* If X-Long-Polling was found, activate long polling */
		if (state->hi.lp_path) {
			if (pool->hdr_path != NULL)
				free(pool->hdr_path);
			pool->hdr_path = state->hi.lp_path;
		} else
			pool->hdr_path = NULL;
		if (state->hi.stratum_url) {
			pool->stratum_url = state->hi.stratum_url;
			state->hi.stratum_url = NULL;
		}
	} else {
		if (state->hi.lp_path) {
			free(state->hi.lp_path);
			state->hi.lp_path = NULL;
		}
		if (state->hi.stratum_url) {
			free(state->hi.stratum_url);
			state->hi.stratum_url = NULL;
		}
	}

	if (rolltime)
		*rolltime = state->hi.rolltime;
	pool->cgminer_pool_stats.rolltime = state->hi.rolltime;
	pool->cgminer_pool_stats.hadrolltime = state->hi.hadrolltime;
	pool->cgminer_pool_stats.canroll = state->hi.canroll;
	pool->cgminer_pool_stats.hadexpire = state->hi.hadexpire;

	val = JSON_LOADS(state->all_data.buf, &err);
	if (!val) {
		applog(LOG_INFO, "JSON decode failed(%d): %s", err.line, err.text);

		if (opt_protocol)
			applog(LOG_DEBUG, "JSON protocol response:\n%s", (char*)state->all_data.buf);

		goto err_out;
	}

	if (opt_protocol) {
		char *s = json_dumps(val, JSON_INDENT(3));

		applog(LOG_DEBUG, "JSON protocol response:\n%s", s);
		free(s);
	}

	/* JSON-RPC valid response returns a non-null 'result',
	 * and a null 'error'.
	 */
	res_val = json_object_get(val, "result");
	err_val = json_object_get(val, "error");

	if (!res_val ||(err_val && !json_is_null(err_val))) {
		char *s;

		if (err_val)
			s = json_dumps(err_val, JSON_INDENT(3));
		else
			s = strdup("(unknown reason)");

		applog(LOG_INFO, "JSON-RPC call failed: %s", s);

		free(s);
		json_decref(val);

		goto err_out;
	}

	if (state->hi.reason) {
		json_object_set_new(val, "reject-reason", json_string(state->hi.reason));
		free(state->hi.reason);
		state->hi.reason = NULL;
	}
	successful_connect = true;
	databuf_free(&state->all_data);
	curl_slist_free_all(state->headers);
	curl_easy_reset(curl);
	free(state);
	return val;

err_out:
	databuf_free(&state->all_data);
	curl_slist_free_all(state->headers);
	curl_easy_reset(curl);
	if (!successful_connect)
		applog(LOG_DEBUG, "Failed to connect in json_rpc_call");
	curl_easy_setopt(curl, CURLOPT_FRESH_CONNECT, 1);
	free(state);
	return NULL;
}

json_t *json_rpc_call(CURL *curl, const char *url,
		      const char *userpass, const char *rpc_req,
		      bool probe, bool longpoll, int *rolltime,
		      struct pool *pool, bool share)
{
	json_rpc_call_async(curl, url, userpass, rpc_req, longpoll, pool, share, NULL);
	int rc = curl_easy_perform(curl);
	return json_rpc_call_completed(curl, rc, probe, rolltime, NULL);
}

bool our_curl_supports_proxy_uris()
{
	curl_version_info_data *data = curl_version_info(CURLVERSION_NOW);
	return data->age && data->version_num >= (( 7 <<16)|( 21 <<8)| 7);  // 7.21.7
}

// NOTE: This assumes reference URI is a root
char *absolute_uri(char *uri, const char *ref)
{
	if (strstr(uri, "://"))
		return strdup(uri);

	char *copy_start, *abs;
	bool need_slash = false;

	copy_start = (uri[0] == '/') ? &uri[1] : uri;
	if (ref[strlen(ref) - 1] != '/')
		need_slash = true;

	abs = malloc(strlen(ref) + strlen(copy_start) + 2);
	if (!abs) {
		applog(LOG_ERR, "Malloc failure in absolute_uri");
		return NULL;
	}

	sprintf(abs, "%s%s%s", ref, need_slash ? "/" : "", copy_start);

	return abs;
}

/* Returns a malloced array string of a binary value of arbitrary length. The
 * array is rounded up to a 4 byte size to appease architectures that need
 * aligned array  sizes */
char *bin2hex(const unsigned char *p, size_t len)
{
	unsigned int i;
	ssize_t slen;
	char *s;

	slen = len * 2 + 1;
	if (slen % 4)
		slen += 4 - (slen % 4);
	s = calloc(slen, 1);
	if (unlikely(!s))
		quit(1, "Failed to calloc in bin2hex");

	for (i = 0; i < len; i++)
		sprintf(s + (i * 2), "%02x", (unsigned int) p[i]);

	return s;
}

/* Does the reverse of bin2hex but does not allocate any ram */
bool hex2bin(unsigned char *p, const char *hexstr, size_t len)
{
	bool ret = false;

	while (*hexstr && len) {
		char hex_byte[4];
		unsigned int v;

		if (unlikely(!hexstr[1])) {
			applog(LOG_ERR, "hex2bin str truncated");
			return ret;
		}

		memset(hex_byte, 0, 4);
		hex_byte[0] = hexstr[0];
		hex_byte[1] = hexstr[1];

		if (unlikely(sscanf(hex_byte, "%x", &v) != 1)) {
			applog(LOG_ERR, "hex2bin sscanf '%s' failed", hex_byte);
			return ret;
		}

		*p = (unsigned char) v;

		p++;
		hexstr += 2;
		len--;
	}

	if (likely(len == 0 && *hexstr == 0))
		ret = true;
	return ret;
}

void hash_data(unsigned char *out_hash, const unsigned char *data)
{
	unsigned char blkheader[80];
	
	// data is past the first SHA256 step (padding and interpreting as big endian on a little endian platform), so we need to flip each 32-bit chunk around to get the original input block header
	swap32yes(blkheader, data, 80 / 4);
	
	// double-SHA256 to get the block hash
	gen_hash(blkheader, out_hash, 80);
}

void real_block_target(unsigned char *target, const unsigned char *data)
{
	uint8_t targetshift;

	if (unlikely(data[72] < 3 || data[72] > 0x20))
	{
		// Invalid (out of bounds) target
		memset(target, 0xff, 32);
		return;
	}

	targetshift = data[72] - 3;
	memset(target, 0, targetshift);
	target[targetshift++] = data[75];
	target[targetshift++] = data[74];
	target[targetshift++] = data[73];
	memset(&target[targetshift], 0, 0x20 - targetshift);
}

bool hash_target_check(const unsigned char *hash, const unsigned char *target)
{
	const uint32_t *h32 = (uint32_t*)&hash[0];
	const uint32_t *t32 = (uint32_t*)&target[0];
	for (int i = 7; i >= 0; --i) {
		uint32_t h32i = le32toh(h32[i]);
		uint32_t t32i = le32toh(t32[i]);
		if (h32i > t32i)
			return false;
		if (h32i < t32i)
			return true;
	}
	return true;
}

bool hash_target_check_v(const unsigned char *hash, const unsigned char *target)
{
	bool rc;

	rc = hash_target_check(hash, target);

	if (opt_debug) {
		unsigned char hash_swap[32], target_swap[32];
		char *hash_str, *target_str;

		for (int i = 0; i < 32; ++i) {
			hash_swap[i] = hash[31-i];
			target_swap[i] = target[31-i];
		}

		hash_str = bin2hex(hash_swap, 32);
		target_str = bin2hex(target_swap, 32);

		applog(LOG_DEBUG, " Proof: %s\nTarget: %s\nTrgVal? %s",
			hash_str,
			target_str,
			rc ? "YES (hash < target)" :
			     "no (false positive; hash > target)");

		free(hash_str);
		free(target_str);
	}

	return rc;
}

// This operates on a native-endian SHA256 state
// In other words, on little endian platforms, every 4 bytes are in reverse order
bool fulltest(const unsigned char *hash, const unsigned char *target)
{
	unsigned char hash2[32];
	swap32tobe(hash2, hash, 32 / 4);
	return hash_target_check_v(hash2, target);
}

struct thread_q *tq_new(void)
{
	struct thread_q *tq;

	tq = calloc(1, sizeof(*tq));
	if (!tq)
		return NULL;

	INIT_LIST_HEAD(&tq->q);
	pthread_mutex_init(&tq->mutex, NULL);
	pthread_cond_init(&tq->cond, NULL);

	return tq;
}

void tq_free(struct thread_q *tq)
{
	struct tq_ent *ent, *iter;

	if (!tq)
		return;

	list_for_each_entry_safe(ent, iter, &tq->q, q_node) {
		list_del(&ent->q_node);
		free(ent);
	}

	pthread_cond_destroy(&tq->cond);
	pthread_mutex_destroy(&tq->mutex);

	memset(tq, 0, sizeof(*tq));	/* poison */
	free(tq);
}

static void tq_freezethaw(struct thread_q *tq, bool frozen)
{
	mutex_lock(&tq->mutex);

	tq->frozen = frozen;

	pthread_cond_signal(&tq->cond);
	mutex_unlock(&tq->mutex);
}

void tq_freeze(struct thread_q *tq)
{
	tq_freezethaw(tq, true);
}

void tq_thaw(struct thread_q *tq)
{
	tq_freezethaw(tq, false);
}

bool tq_push(struct thread_q *tq, void *data)
{
	struct tq_ent *ent;
	bool rc = true;

	ent = calloc(1, sizeof(*ent));
	if (!ent)
		return false;

	ent->data = data;
	INIT_LIST_HEAD(&ent->q_node);

	mutex_lock(&tq->mutex);

	if (!tq->frozen) {
		list_add_tail(&ent->q_node, &tq->q);
	} else {
		free(ent);
		rc = false;
	}

	pthread_cond_signal(&tq->cond);
	mutex_unlock(&tq->mutex);

	return rc;
}

void *tq_pop(struct thread_q *tq, const struct timespec *abstime)
{
	struct tq_ent *ent;
	void *rval = NULL;
	int rc;

	mutex_lock(&tq->mutex);

	if (!list_empty(&tq->q))
		goto pop;

	if (abstime)
		rc = pthread_cond_timedwait(&tq->cond, &tq->mutex, abstime);
	else
		rc = pthread_cond_wait(&tq->cond, &tq->mutex);
	if (rc)
		goto out;
	if (list_empty(&tq->q))
		goto out;

pop:
	ent = list_entry(tq->q.next, struct tq_ent, q_node);
	rval = ent->data;

	list_del(&ent->q_node);
	free(ent);

out:
	mutex_unlock(&tq->mutex);
	return rval;
}

int thr_info_create(struct thr_info *thr, pthread_attr_t *attr, void *(*start) (void *), void *arg)
{
	return pthread_create(&thr->pth, attr, start, arg);
}

void thr_info_freeze(struct thr_info *thr)
{
	struct tq_ent *ent, *iter;
	struct thread_q *tq;

	if (!thr)
		return;

	tq = thr->q;
	if (!tq)
		return;

	mutex_lock(&tq->mutex);
	tq->frozen = true;
	list_for_each_entry_safe(ent, iter, &tq->q, q_node) {
		list_del(&ent->q_node);
		free(ent);
	}
	mutex_unlock(&tq->mutex);
}

void thr_info_cancel(struct thr_info *thr)
{
	if (!thr)
		return;

	if (PTH(thr) != 0L) {
		pthread_cancel(thr->pth);
		PTH(thr) = 0L;
	}
}

/* Provide a ms based sleep that uses nanosleep to avoid poor usleep accuracy
 * on SMP machines */
void nmsleep(unsigned int msecs)
{
	struct timespec twait, tleft;
	int ret;
	ldiv_t d;

	d = ldiv(msecs, 1000);
	tleft.tv_sec = d.quot;
	tleft.tv_nsec = d.rem * 1000000;
	do {
		twait.tv_sec = tleft.tv_sec;
		twait.tv_nsec = tleft.tv_nsec;
		ret = nanosleep(&twait, &tleft);
	} while (ret == -1 && errno == EINTR);
}

/* Returns the microseconds difference between end and start times as a double */
double us_tdiff(struct timeval *end, struct timeval *start)
{
	return end->tv_sec * 1000000 + end->tv_usec - start->tv_sec * 1000000 - start->tv_usec;
}

/* Returns the seconds difference between end and start times as a double */
double tdiff(struct timeval *end, struct timeval *start)
{
	return end->tv_sec - start->tv_sec + (end->tv_usec - start->tv_usec) / 1000000.0;
}

bool extract_sockaddr(struct pool *pool, char *url)
{
	char *url_begin, *url_end, *ipv6_begin, *ipv6_end, *port_start = NULL;
	char url_address[256], port[6];
	int url_len, port_len = 0;

	url_begin = strstr(url, "//");
	if (!url_begin)
		url_begin = url;
	else
		url_begin += 2;

	/* Look for numeric ipv6 entries */
	ipv6_begin = strstr(url_begin, "[");
	ipv6_end = strstr(url_begin, "]");
	if (ipv6_begin && ipv6_end && ipv6_end > ipv6_begin)
		url_end = strstr(ipv6_end, ":");
	else
		url_end = strstr(url_begin, ":");
	if (url_end) {
		url_len = url_end - url_begin;
		port_len = strlen(url_begin) - url_len - 1;
		if (port_len < 1)
			return false;
		port_start = url_end + 1;
	} else
		url_len = strlen(url_begin);

	if (url_len < 1)
		return false;

	sprintf(url_address, "%.*s", url_len, url_begin);

	if (port_len)
		snprintf(port, 6, "%.*s", port_len, port_start);
	else
		strcpy(port, "80");

	free(pool->stratum_port);
	pool->stratum_port = strdup(port);
	free(pool->sockaddr_url);
	pool->sockaddr_url = strdup(url_address);

	return true;
}

/* Send a single command across a socket, appending \n to it. This should all
 * be done under stratum lock except when first establishing the socket */
static bool __stratum_send(struct pool *pool, char *s, ssize_t len)
{
	SOCKETTYPE sock = pool->sock;
	ssize_t ssent = 0;

	if (opt_protocol)
		applog(LOG_DEBUG, "SEND: %s", s);

	strcat(s, "\n");
	len++;

	while (len > 0 ) {
		struct timeval timeout = {0, 0};
		ssize_t sent;
		fd_set wd;

		FD_ZERO(&wd);
		FD_SET(sock, &wd);
		if (select(sock + 1, NULL, &wd, NULL, &timeout) < 1) {
			applog(LOG_DEBUG, "Write select failed on pool %d sock", pool->pool_no);
			return false;
		}
		sent = send(pool->sock, s + ssent, len, 0);
		if (sent < 0) {
			if (errno != EAGAIN && errno != EWOULDBLOCK) {
				applog(LOG_DEBUG, "Failed to curl_easy_send in stratum_send");
				return false;
			}
			sent = 0;
		}
		ssent += sent;
		len -= sent;
	}

	pool->cgminer_pool_stats.times_sent++;
	pool->cgminer_pool_stats.bytes_sent += ssent;
	total_bytes_xfer += ssent;
	pool->cgminer_pool_stats.net_bytes_sent += ssent;
	return true;
}

bool stratum_send(struct pool *pool, char *s, ssize_t len)
{
	bool ret = false;

	mutex_lock(&pool->stratum_lock);
	if (pool->stratum_active)
		ret = __stratum_send(pool, s, len);
	else
		applog(LOG_DEBUG, "Stratum send failed due to no pool stratum_active");
	mutex_unlock(&pool->stratum_lock);

	return ret;
}

static bool socket_full(struct pool *pool, bool wait)
{
	SOCKETTYPE sock = pool->sock;
	struct timeval timeout;
	fd_set rd;

	FD_ZERO(&rd);
	FD_SET(sock, &rd);
	timeout.tv_usec = 0;
	if (wait)
		timeout.tv_sec = 60;
	else
		timeout.tv_sec = 0;
	if (select(sock + 1, &rd, NULL, NULL, &timeout) > 0)
		return true;
	return false;
}

/* Check to see if Santa's been good to you */
bool sock_full(struct pool *pool)
{
	if (strlen(pool->sockbuf))
		return true;

	return (socket_full(pool, false));
}

static void clear_sock(struct pool *pool)
{
	ssize_t n;

	mutex_lock(&pool->stratum_lock);
	do
		n = recv(pool->sock, pool->sockbuf, RECVSIZE, 0);
	while (n > 0);
	mutex_unlock(&pool->stratum_lock);
	strcpy(pool->sockbuf, "");
}

/* Make sure the pool sockbuf is large enough to cope with any coinbase size
 * by reallocing it to a large enough size rounded up to a multiple of RBUFSIZE
 * and zeroing the new memory */
static void recalloc_sock(struct pool *pool, size_t len)
{
	size_t old, new;

	old = strlen(pool->sockbuf);
	new = old + len + 1;
	if (new < pool->sockbuf_size)
		return;
	new = new + (RBUFSIZE - (new % RBUFSIZE));
	applog(LOG_DEBUG, "Recallocing pool sockbuf to %lu", (unsigned long)new);
	pool->sockbuf = realloc(pool->sockbuf, new);
	if (!pool->sockbuf)
		quit(1, "Failed to realloc pool sockbuf in recalloc_sock");
	memset(pool->sockbuf + old, 0, new - old);
	pool->sockbuf_size = new;
}

/* Peeks at a socket to find the first end of line and then reads just that
 * from the socket and returns that as a malloced char */
char *recv_line(struct pool *pool)
{
	ssize_t len, buflen;
	char *tok, *sret = NULL;

	if (!strstr(pool->sockbuf, "\n")) {
		struct timeval rstart, now;

		gettimeofday(&rstart, NULL);
		if (!socket_full(pool, true)) {
			applog(LOG_DEBUG, "Timed out waiting for data on socket_full");
			goto out;
		}

		mutex_lock(&pool->stratum_lock);
		do {
			char s[RBUFSIZE];
			size_t slen, n;

			memset(s, 0, RBUFSIZE);
			n = recv(pool->sock, s, RECVSIZE, 0);
			if (n < 1 && errno != EAGAIN && errno != EWOULDBLOCK) {
				applog(LOG_DEBUG, "Failed to recv sock in recv_line");
				break;
			}
			slen = strlen(s);
			recalloc_sock(pool, slen);
			strcat(pool->sockbuf, s);
			gettimeofday(&now, NULL);
		} while (tdiff(&now, &rstart) < 60 && !strstr(pool->sockbuf, "\n"));
		mutex_unlock(&pool->stratum_lock);
	}

	buflen = strlen(pool->sockbuf);
	tok = strtok(pool->sockbuf, "\n");
	if (!tok) {
		applog(LOG_DEBUG, "Failed to parse a \\n terminated string in recv_line");
		goto out;
	}
	sret = strdup(tok);
	len = strlen(sret);

	/* Copy what's left in the buffer after the \n, including the
	 * terminating \0 */
	if (buflen > len + 1)
		memmove(pool->sockbuf, pool->sockbuf + len + 1, buflen - len + 1);
	else
		strcpy(pool->sockbuf, "");

	pool->cgminer_pool_stats.times_received++;
	pool->cgminer_pool_stats.bytes_received += len;
	total_bytes_xfer += len;
	pool->cgminer_pool_stats.net_bytes_received += len;

out:
	if (!sret)
		clear_sock(pool);
	else if (opt_protocol)
		applog(LOG_DEBUG, "RECVD: %s", sret);
	return sret;
}

/* Extracts a string value from a json array with error checking. To be used
 * when the value of the string returned is only examined and not to be stored.
 * See json_array_string below */
static char *__json_array_string(json_t *val, unsigned int entry)
{
	json_t *arr_entry;

	if (json_is_null(val))
		return NULL;
	if (!json_is_array(val))
		return NULL;
	if (entry > json_array_size(val))
		return NULL;
	arr_entry = json_array_get(val, entry);
	if (!json_is_string(arr_entry))
		return NULL;

	return (char *)json_string_value(arr_entry);
}

/* Creates a freshly malloced dup of __json_array_string */
static char *json_array_string(json_t *val, unsigned int entry)
{
	char *buf = __json_array_string(val, entry);

	if (buf)
		return strdup(buf);
	return NULL;
}

void stratum_probe_transparency(struct pool *pool)
{
	// Request transaction data to discourage pools from doing anything shady
	char s[1024];
	int sLen;
	sLen = sprintf(s, "{\"params\": [\"%s\"], \"id\": \"txlist%s\", \"method\": \"mining.get_transactions\"}",
	        pool->swork.job_id,
	        pool->swork.job_id);
	stratum_send(pool, s, sLen);
	if ((!pool->swork.opaque) && pool->swork.transparency_time == (time_t)-1)
		pool->swork.transparency_time = time(NULL);
	pool->swork.transparency_probed = true;
}

static bool parse_notify(struct pool *pool, json_t *val)
{
	char *job_id, *prev_hash, *coinbase1, *coinbase2, *bbversion, *nbit, *ntime;
	bool clean, ret = false;
	int merkles, i;
	json_t *arr;

	arr = json_array_get(val, 4);
	if (!arr || !json_is_array(arr))
		goto out;

	merkles = json_array_size(arr);

	job_id = json_array_string(val, 0);
	prev_hash = json_array_string(val, 1);
	coinbase1 = json_array_string(val, 2);
	coinbase2 = json_array_string(val, 3);
	bbversion = json_array_string(val, 5);
	nbit = json_array_string(val, 6);
	ntime = json_array_string(val, 7);
	clean = json_is_true(json_array_get(val, 8));

	if (!job_id || !prev_hash || !coinbase1 || !coinbase2 || !bbversion || !nbit || !ntime) {
		/* Annoying but we must not leak memory */
		if (job_id)
			free(job_id);
		if (prev_hash)
			free(prev_hash);
		if (coinbase1)
			free(coinbase1);
		if (coinbase2)
			free(coinbase2);
		if (bbversion)
			free(bbversion);
		if (nbit)
			free(nbit);
		if (ntime)
			free(ntime);
		goto out;
	}

	mutex_lock(&pool->pool_lock);
	free(pool->swork.job_id);
	free(pool->swork.prev_hash);
	free(pool->swork.coinbase1);
	free(pool->swork.coinbase2);
	free(pool->swork.bbversion);
	free(pool->swork.nbit);
	free(pool->swork.ntime);
	pool->swork.job_id = job_id;
	pool->swork.prev_hash = prev_hash;
	pool->swork.coinbase1 = coinbase1;
	pool->swork.cb1_len = strlen(coinbase1) / 2;
	pool->swork.coinbase2 = coinbase2;
	pool->swork.cb2_len = strlen(coinbase2) / 2;
	pool->swork.bbversion = bbversion;
	pool->swork.nbit = nbit;
	pool->swork.ntime = ntime;
	pool->submit_old = !clean;
	pool->swork.clean = true;
	pool->swork.cb_len = pool->swork.cb1_len + pool->n1_len + pool->n2size + pool->swork.cb2_len;

	for (i = 0; i < pool->swork.merkles; i++)
		free(pool->swork.merkle[i]);
	if (merkles) {
		pool->swork.merkle = realloc(pool->swork.merkle, sizeof(char *) * merkles + 1);
		for (i = 0; i < merkles; i++)
			pool->swork.merkle[i] = json_array_string(arr, i);
	}
	pool->swork.merkles = merkles;
	if (clean)
		pool->nonce2 = 0;
	pool->swork.header_len = strlen(pool->swork.bbversion) +
				 strlen(pool->swork.prev_hash) +
				 strlen(pool->swork.ntime) +
				 strlen(pool->swork.nbit) +
	/* merkle_hash */	 32 +
	/* nonce */		 8 +
	/* workpadding */	 96;
	pool->swork.header_len = pool->swork.header_len * 2 + 1;
	align_len(&pool->swork.header_len);
	mutex_unlock(&pool->pool_lock);

	applog(LOG_DEBUG, "Received stratum notify from pool %u with job_id=%s",
	       pool->pool_no, job_id);
	if (opt_protocol) {
		applog(LOG_DEBUG, "job_id: %s", job_id);
		applog(LOG_DEBUG, "prev_hash: %s", prev_hash);
		applog(LOG_DEBUG, "coinbase1: %s", coinbase1);
		applog(LOG_DEBUG, "coinbase2: %s", coinbase2);
		for (i = 0; i < merkles; i++)
			applog(LOG_DEBUG, "merkle%d: %s", i, pool->swork.merkle[i]);
		applog(LOG_DEBUG, "bbversion: %s", bbversion);
		applog(LOG_DEBUG, "nbit: %s", nbit);
		applog(LOG_DEBUG, "ntime: %s", ntime);
		applog(LOG_DEBUG, "clean: %s", clean ? "yes" : "no");
	}

	/* A notify message is the closest stratum gets to a getwork */
	pool->getwork_requested++;
	total_getworks++;

	if ((merkles && (!pool->swork.transparency_probed || rand() <= RAND_MAX / (opt_skip_checks + 1))) || pool->swork.transparency_time != (time_t)-1)
		if (pool->stratum_auth)
			stratum_probe_transparency(pool);

	ret = true;
out:
	return ret;
}

static bool parse_diff(struct pool *pool, json_t *val)
{
	double diff;

	diff = json_number_value(json_array_get(val, 0));
	if (diff == 0)
		return false;

	mutex_lock(&pool->pool_lock);
	pool->swork.diff = diff;
	mutex_unlock(&pool->pool_lock);

	applog(LOG_DEBUG, "Pool %d difficulty set to %f", pool->pool_no, diff);

	return true;
}

static bool parse_reconnect(struct pool *pool, json_t *val)
{
	char *url, *port, address[256];

	memset(address, 0, 255);
	url = (char *)json_string_value(json_array_get(val, 0));
	if (!url)
		url = pool->sockaddr_url;

	port = (char *)json_string_value(json_array_get(val, 1));
	if (!port)
		port = pool->stratum_port;

	sprintf(address, "%s:%s", url, port);

	if (!extract_sockaddr(pool, address))
		return false;

	pool->stratum_url = pool->sockaddr_url;

	applog(LOG_NOTICE, "Reconnect requested from pool %d to %s", pool->pool_no, address);

	if (!initiate_stratum(pool) || !auth_stratum(pool))
		return false;

	return true;
}

static bool send_version(struct pool *pool, json_t *val)
{
	char s[RBUFSIZE];
	int id = json_integer_value(json_object_get(val, "id"));
	
	if (!id)
		return false;

	sprintf(s, "{\"id\": %d, \"result\": \""PACKAGE"/"VERSION"\", \"error\": null}", id);
	if (!stratum_send(pool, s, strlen(s)))
		return false;

	return true;
}

bool parse_method(struct pool *pool, char *s)
{
	json_t *val = NULL, *method, *err_val, *params;
	json_error_t err;
	bool ret = false;
	char *buf;

	if (!s)
		goto out;

	val = JSON_LOADS(s, &err);
	if (!val) {
		applog(LOG_INFO, "JSON decode failed(%d): %s", err.line, err.text);
		goto out;
	}

	method = json_object_get(val, "method");
	if (!method)
		goto out;
	err_val = json_object_get(val, "error");
	params = json_object_get(val, "params");

	if (err_val && !json_is_null(err_val)) {
		char *ss;

		if (err_val)
			ss = json_dumps(err_val, JSON_INDENT(3));
		else
			ss = strdup("(unknown reason)");

		applog(LOG_INFO, "JSON-RPC method decode failed: %s", ss);

		free(ss);

		goto out;
	}

	buf = (char *)json_string_value(method);
	if (!buf)
		goto out;

	if (!strncasecmp(buf, "mining.notify", 13)) {
		if (parse_notify(pool, params))
			pool->stratum_notify = ret = true;
		else
			pool->stratum_notify = ret = false;
		goto out;
	}

	if (!strncasecmp(buf, "mining.set_difficulty", 21) && parse_diff(pool, params)) {
		ret = true;
		goto out;
	}

	if (!strncasecmp(buf, "client.reconnect", 16) && parse_reconnect(pool, params)) {
		ret = true;
		goto out;
	}

	if (!strncasecmp(buf, "client.get_version", 18) && send_version(pool, val)) {
		ret = true;
		goto out;
	}
out:
	if (val)
		json_decref(val);

	return ret;
}

extern bool parse_stratum_response(struct pool *, char *s);

bool auth_stratum(struct pool *pool)
{
	json_t *val = NULL, *res_val, *err_val;
	char s[RBUFSIZE], *sret = NULL;
	json_error_t err;
	bool ret = false;

	sprintf(s, "{\"id\": \"auth\", \"method\": \"mining.authorize\", \"params\": [\"%s\", \"%s\"]}",
	        pool->rpc_user, pool->rpc_pass);

	if (!stratum_send(pool, s, strlen(s)))
		goto out;

	/* Parse all data in the queue and anything left should be auth */
	while (42) {
		sret = recv_line(pool);
		if (!sret)
			goto out;
		if (parse_method(pool, sret))
			free(sret);
		else
			break;
	}

	val = JSON_LOADS(sret, &err);
	free(sret);
	res_val = json_object_get(val, "result");
	err_val = json_object_get(val, "error");

	if (!res_val || json_is_false(res_val) || (err_val && !json_is_null(err_val)))  {
		char *ss;

		if (err_val)
			ss = json_dumps(err_val, JSON_INDENT(3));
		else
			ss = strdup("(unknown reason)");
		applog(LOG_WARNING, "JSON stratum auth failed: %s", ss);
		free(ss);

		goto out;
	}

	ret = true;
	applog(LOG_INFO, "Stratum authorisation success for pool %d", pool->pool_no);
	pool->probed = true;
	pool->stratum_auth = true;
	successful_connect = true;
out:
	if (val)
		json_decref(val);

	if (pool->stratum_notify)
		stratum_probe_transparency(pool);

	return ret;
}

curl_socket_t grab_socket_opensocket_cb(void *clientp, curlsocktype purpose, struct curl_sockaddr *addr)
{
	struct pool *pool = clientp;
	curl_socket_t sck = socket(addr->family, addr->socktype, addr->protocol);
	pool->sock = sck;
	return sck;
}

bool initiate_stratum(struct pool *pool)
{
	json_t *val = NULL, *res_val, *err_val;
	char curl_err_str[CURL_ERROR_SIZE];
	char s[RBUFSIZE], *sret = NULL;
	CURL *curl = NULL;
	json_error_t err;
	bool ret = false;

	applog(LOG_DEBUG, "initiate_stratum with sockbuf=%p", pool->sockbuf);
	mutex_lock(&pool->stratum_lock);
	pool->swork.transparency_time = (time_t)-1;
	pool->stratum_active = false;
	pool->stratum_auth = false;
	pool->stratum_notify = false;
	pool->swork.transparency_probed = false;
	if (!pool->stratum_curl) {
		pool->stratum_curl = curl_easy_init();
		if (unlikely(!pool->stratum_curl))
			quit(1, "Failed to curl_easy_init in initiate_stratum");
	}
	if (pool->sockbuf)
		pool->sockbuf[0] = '\0';
	mutex_unlock(&pool->stratum_lock);
	curl = pool->stratum_curl;

	if (!pool->sockbuf) {
		pool->sockbuf = calloc(RBUFSIZE, 1);
		if (!pool->sockbuf)
			quit(1, "Failed to calloc pool sockbuf in initiate_stratum");
		pool->sockbuf_size = RBUFSIZE;
	}

	/* Create a http url for use with curl */
	memset(s, 0, RBUFSIZE);
	sprintf(s, "http://%s:%s", pool->sockaddr_url, pool->stratum_port);

	curl_easy_setopt(curl, CURLOPT_FRESH_CONNECT, 1);
	curl_easy_setopt(curl, CURLOPT_CONNECTTIMEOUT, 30);
	curl_easy_setopt(curl, CURLOPT_ERRORBUFFER, curl_err_str);
	curl_easy_setopt(curl, CURLOPT_NOSIGNAL, 1);
	curl_easy_setopt(curl, CURLOPT_URL, s);
	curl_easy_setopt(curl, CURLOPT_TCP_NODELAY, 1);

	/* We use DEBUGFUNCTION to count bytes sent/received, and verbose is needed
	 * to enable it */
	curl_easy_setopt(curl, CURLOPT_DEBUGFUNCTION, curl_debug_cb);
	curl_easy_setopt(curl, CURLOPT_DEBUGDATA, (void *)pool);
	curl_easy_setopt(curl, CURLOPT_VERBOSE, 1);

	// CURLINFO_LASTSOCKET is broken on Win64 (which has a wider SOCKET type than curl_easy_getinfo returns), so we use this hack for now
	curl_easy_setopt(curl, CURLOPT_OPENSOCKETFUNCTION, grab_socket_opensocket_cb);
	curl_easy_setopt(curl, CURLOPT_OPENSOCKETDATA, pool);
	
	curl_easy_setopt(curl, CURLOPT_USE_SSL, CURLUSESSL_TRY);
	if (pool->rpc_proxy) {
		curl_easy_setopt(curl, CURLOPT_PROXY, pool->rpc_proxy);
	} else if (opt_socks_proxy) {
		curl_easy_setopt(curl, CURLOPT_PROXY, opt_socks_proxy);
		curl_easy_setopt(curl, CURLOPT_PROXYTYPE, CURLPROXY_SOCKS4);
	}
	curl_easy_setopt(curl, CURLOPT_CONNECT_ONLY, 1);
	pool->sock = INVSOCK;
	if (curl_easy_perform(curl)) {
		applog(LOG_INFO, "Stratum connect failed to pool %d: %s", pool->pool_no, curl_err_str);
		goto out;
	}
	if (pool->sock == INVSOCK)
	{
		curl_easy_cleanup(curl);
		applog(LOG_ERR, "Stratum connect succeeded, but technical problem extracting socket (pool %u)", pool->pool_no);
		goto out;
	}
	keep_sockalive(pool->sock);

	pool->cgminer_pool_stats.times_sent++;
	pool->cgminer_pool_stats.times_received++;

	sprintf(s, "{\"id\": %d, \"method\": \"mining.subscribe\", \"params\": []}", swork_id++);

	if (!__stratum_send(pool, s, strlen(s))) {
		applog(LOG_DEBUG, "Failed to send s in initiate_stratum");
		goto out;
	}

	if (!socket_full(pool, true)) {
		applog(LOG_DEBUG, "Timed out waiting for response in initiate_stratum");
		goto out;
	}

	sret = recv_line(pool);
	if (!sret)
		goto out;

	val = JSON_LOADS(sret, &err);
	free(sret);
	if (!val) {
		applog(LOG_INFO, "JSON decode failed(%d): %s", err.line, err.text);
		goto out;
	}

	res_val = json_object_get(val, "result");
	err_val = json_object_get(val, "error");

	if (!res_val || json_is_null(res_val) ||
	    (err_val && !json_is_null(err_val))) {
		char *ss;

		if (err_val)
			ss = json_dumps(err_val, JSON_INDENT(3));
		else
			ss = strdup("(unknown reason)");

		applog(LOG_INFO, "JSON-RPC decode failed: %s", ss);

		free(ss);

		goto out;
	}

	free(pool->nonce1);
	pool->nonce1 = json_array_string(res_val, 1);
	if (!pool->nonce1) {
		applog(LOG_INFO, "Failed to get nonce1 in initiate_stratum");
		goto out;
	}
	pool->n1_len = strlen(pool->nonce1) / 2;
	pool->n2size = json_integer_value(json_array_get(res_val, 2));
	if (!pool->n2size) {
		applog(LOG_INFO, "Failed to get n2size in initiate_stratum");
		goto out;
	}

	ret = true;
out:
	if (val)
		json_decref(val);

	if (ret) {
		if (!pool->stratum_url)
			pool->stratum_url = pool->sockaddr_url;
		pool->stratum_active = true;
		pool->swork.diff = 1;
		if (opt_protocol) {
			applog(LOG_DEBUG, "Pool %d confirmed mining.subscribe with extranonce1 %s extran2size %d",
			       pool->pool_no, pool->nonce1, pool->n2size);
		}
	} else
	{
		applog(LOG_DEBUG, "Initiate stratum failed");
		if (pool->sock != INVSOCK) {
			shutdown(pool->sock, SHUT_RDWR);
			pool->sock = INVSOCK;
		}
	}

	return ret;
}

void suspend_stratum(struct pool *pool)
{
	applog(LOG_INFO, "Closing socket for stratum pool %d", pool->pool_no);
	mutex_lock(&pool->stratum_lock);
	pool->stratum_active = false;
	pool->stratum_auth = false;
	mutex_unlock(&pool->stratum_lock);
	CLOSESOCKET(pool->sock);
}

void dev_error(struct cgpu_info *dev, enum dev_reason reason)
{
	dev->device_last_not_well = time(NULL);
	dev->device_not_well_reason = reason;

	switch (reason) {
		case REASON_THREAD_FAIL_INIT:
			dev->thread_fail_init_count++;
			break;
		case REASON_THREAD_ZERO_HASH:
			dev->thread_zero_hash_count++;
			break;
		case REASON_THREAD_FAIL_QUEUE:
			dev->thread_fail_queue_count++;
			break;
		case REASON_DEV_SICK_IDLE_60:
			dev->dev_sick_idle_60_count++;
			break;
		case REASON_DEV_DEAD_IDLE_600:
			dev->dev_dead_idle_600_count++;
			break;
		case REASON_DEV_NOSTART:
			dev->dev_nostart_count++;
			break;
		case REASON_DEV_OVER_HEAT:
			dev->dev_over_heat_count++;
			break;
		case REASON_DEV_THERMAL_CUTOFF:
			dev->dev_thermal_cutoff_count++;
			break;
		case REASON_DEV_COMMS_ERROR:
			dev->dev_comms_error_count++;
			break;
		case REASON_DEV_THROTTLE:
			dev->dev_throttle_count++;
			break;
	}
}

/* Realloc an existing string to fit an extra string s, appending s to it. */
void *realloc_strcat(char *ptr, char *s)
{
	size_t old = strlen(ptr), len = strlen(s);
	char *ret;

	if (!len)
		return ptr;

	len += old + 1;
	align_len(&len);

	ret = malloc(len);
	if (unlikely(!ret))
		quit(1, "Failed to malloc in realloc_strcat");

	sprintf(ret, "%s%s", ptr, s);
	free(ptr);
	return ret;
}

void RenameThread(const char* name)
{
#if defined(PR_SET_NAME)
	// Only the first 15 characters are used (16 - NUL terminator)
	prctl(PR_SET_NAME, name, 0, 0, 0);
#elif defined(__APPLE__)
	pthread_setname_np(name);
#elif (defined(__FreeBSD__) || defined(__OpenBSD__))
	pthread_set_name_np(pthread_self(), name);
#else
	// Prevent warnings for unused parameters...
	(void)name;
#endif
}

#ifdef WIN32
static const char *WindowsErrorStr(DWORD dwMessageId)
{
	static LPSTR msg = NULL;
	if (msg)
		LocalFree(msg);
	if (FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM, 0, dwMessageId, 0, (LPSTR)&msg, 0, 0))
		return msg;
	static const char fmt[] = "Error #%ld";
	signed long ldMsgId = dwMessageId;
	int sz = snprintf((char*)&sz, 0, fmt, ldMsgId) + 1;
	msg = (LPTSTR)LocalAlloc(LMEM_FIXED, sz);
	sprintf((char*)msg, fmt, ldMsgId);
	return msg;
}
#endif

void notifier_init(notifier_t pipefd)
{
#ifdef WIN32
	SOCKET listener, connecter, acceptor;
	listener = socket(AF_INET, SOCK_STREAM, 0);
	if (listener == INVALID_SOCKET)
		quit(1, "Failed to create listener socket in create_notifier: %s", WindowsErrorStr(WSAGetLastError()));
	connecter = socket(AF_INET, SOCK_STREAM, 0);
	if (connecter == INVALID_SOCKET)
		quit(1, "Failed to create connect socket in create_notifier: %s", WindowsErrorStr(WSAGetLastError()));
	struct sockaddr_in inaddr = {
		.sin_family = AF_INET,
		.sin_addr = {
			.s_addr = htonl(INADDR_LOOPBACK),
		},
		.sin_port = 0,
	};
	{
		char reuse = 1;
		setsockopt(listener, SOL_SOCKET, SO_REUSEADDR, &reuse, sizeof(reuse));
	}
	if (bind(listener, (struct sockaddr*)&inaddr, sizeof(inaddr)) == SOCKET_ERROR)
		quit(1, "Failed to bind listener socket in create_notifier: %s", WindowsErrorStr(WSAGetLastError()));
	socklen_t inaddr_sz = sizeof(inaddr);
	if (getsockname(listener, (struct sockaddr*)&inaddr, &inaddr_sz) == SOCKET_ERROR)
		quit(1, "Failed to getsockname in create_notifier: %s", WindowsErrorStr(WSAGetLastError()));
	if (listen(listener, 1) == SOCKET_ERROR)
		quit(1, "Failed to listen in create_notifier: %s", WindowsErrorStr(WSAGetLastError()));
	inaddr.sin_family = AF_INET;
	inaddr.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
	if (connect(connecter, (struct sockaddr*)&inaddr, inaddr_sz) == SOCKET_ERROR)
		quit(1, "Failed to connect in create_notifier: %s", WindowsErrorStr(WSAGetLastError()));
	acceptor = accept(listener, NULL, NULL);
	if (acceptor == INVALID_SOCKET)
		quit(1, "Failed to accept in create_notifier: %s", WindowsErrorStr(WSAGetLastError()));
	closesocket(listener);
	pipefd[0] = connecter;
	pipefd[1] = acceptor;
#else
	if (pipe(pipefd))
		quit(1, "Failed to create pipe in create_notifier");
#endif
}

void notifier_wake(notifier_t fd)
{
	if (fd[1] == INVSOCK)
		return;
#ifdef WIN32
	(void)send(fd[1], "\0", 1, 0);
#else
	(void)write(fd[1], "\0", 1);
#endif
}

void notifier_read(notifier_t fd)
{
	char buf[0x10];
#ifdef WIN32
	(void)recv(fd[0], buf, sizeof(buf), 0);
#else
	(void)read(fd[0], buf, sizeof(buf));
#endif
}

void notifier_destroy(notifier_t fd)
{
#ifdef WIN32
	closesocket(fd[0]);
	closesocket(fd[1]);
#else
	close(fd[0]);
	close(fd[1]);
#endif
	fd[0] = fd[1] = INVSOCK;
}