git ssb

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/* See LICENSE file for copyright and license details. */
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#include <err.h>
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#include <errno.h>
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#include <netdb.h>
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#include <netinet/in.h>
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#include <stdbool.h>
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#include <string.h>
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#include <sys/socket.h>
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#include <unistd.h>
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#include <openssl/ssl.h>
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static int tcp_connect(const char *host, const char *port) {
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	struct addrinfo hints;
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	struct addrinfo *result, *rp;
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	int s;
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	int fd;
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	int err;
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	memset(&hints, 0, sizeof(hints));
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	hints.ai_family = AF_UNSPEC;
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	hints.ai_protocol = IPPROTO_TCP;
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	s = getaddrinfo(host, port, &hints, &result);
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	if (s < 0) errx(1, "unable to resolve host: %s", gai_strerror(s));
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	for (rp = result; rp; rp = rp->ai_next) {
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		fd = socket(rp->ai_family, rp->ai_socktype, rp->ai_protocol);
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		if (fd < 0) continue;
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		if (connect(fd, rp->ai_addr, rp->ai_addrlen) == 0) break;
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		err = errno;
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		close(fd);
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		errno = err;
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	}
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	if (rp == NULL) fd = -1;
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	freeaddrinfo(result);
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	return fd;
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}
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static int write_all(int fd, const void *buf, size_t count) {
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	ssize_t nbytes;
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	while (count > 0) {
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		nbytes = write(fd, buf, count);
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		if (nbytes < 0 && errno == EINTR) continue;
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		if (nbytes < 0) return -1;
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		buf += nbytes;
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		count -= nbytes;
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	}
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	return 0;
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}
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static void usage() {
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	fputs("usage: electrumc <host> <port> <method> [<params>]\n", stderr);
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	exit(EXIT_FAILURE);
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}
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static int read_response(int s, SSL *ssl, bool use_ssl) {
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	char buf[8192];
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	int len;
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	if (use_ssl) {
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		len = SSL_pending(ssl);
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		if (len < 0) errx(1, "ssl pending");
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		if (len == 0) len = 1;
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		else if (len > (int)sizeof(buf)) len = sizeof(buf);
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		len = SSL_read(ssl, buf, len);
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		if (len < 0) errx(1, "ssl read failed");
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	} else {
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		len = read(s, buf, sizeof(buf));
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		if (len == 0) return -1;
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		if (len < 0) err(1, "read");
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	}
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	len = fwrite(buf, 1, len, stdout);
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	if (len < 0) errx(1, "failed to print response");
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	if (buf[len-1] == '\n') return 1;
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	return 0;
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}
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int main(int argc, char *argv[]) {
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	int rc;
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	SSL *ssl;
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	SSL_CTX *ssl_ctx;
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	const char *host, *port, *method, *params;
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	int s;
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	bool use_ssl;
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	if (argc != 4 && argc != 5) usage();
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	host = argv[1];
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	port = argv[2];
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	method = argv[3];
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	params = argc == 4 ? NULL : argv[4];
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	switch (port[0]) {
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		case 't': use_ssl = false; break;
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		case 's': use_ssl = true; break;
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		default: errx(1, "port should begin with 't' for TCP or 's' for TCP+SSL");
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	}
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	port++;
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	if (use_ssl) {
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		ssl_ctx = SSL_CTX_new(TLS_client_method());
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		if (ssl_ctx == NULL) errx(1, "failed to create ssl context");
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		(void)SSL_CTX_set_mode(ssl_ctx, SSL_MODE_AUTO_RETRY);
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		ssl = SSL_new(ssl_ctx);
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		if (ssl_ctx == NULL) errx(1, "failed to create ssl object");
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	}
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	s = tcp_connect(host, port);
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	if (s < 0) err(1, "failed to connect");
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	if (use_ssl) {
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		rc = SSL_set_fd(ssl, s);
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		if (rc < 0) errx(1, "failed to set ssl s");
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		rc = SSL_connect(ssl);
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		if (rc < 0)	errx(1, "ssl_connect failed");
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	}
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	char buf[8192];
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	int len = snprintf(buf, sizeof(buf)-1, "{\"id\":0,\"method\":\"%s\"%s%s}\n",
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	                   method,
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	                   params ? ",\"params\":" : "",
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	                   params ? params : "");
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	if (len < 0 || len == (int)sizeof(buf)) errx(1, "request too long");
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	if (use_ssl) {
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		rc = SSL_write(ssl, buf, len);
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		if (rc < 0) errx(1, "ssl write failed");
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	} else {
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		len = write_all(s, buf, len);
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		if (len < 0) err(1, "write");
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	}
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	do rc = read_response(s, ssl, use_ssl);
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	while (rc == 0);
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	if (rc < 0 && errno == 0)  errx(1, "incomplete response");
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	if (rc < 0) err(1, "read");
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	if (use_ssl) {
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		rc = SSL_shutdown(ssl);
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		if (rc < 0) errx(1, "ssl shutdown failed");
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	}
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	close(s);
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}
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