resolve hostname

disk_backend_nbd.cpp

@@ -12,16 +12,9 @@
 
 
 disk_backend_nbd::disk_backend_nbd(const std::string & host, const int port) :
-	fd(socket(AF_INET, SOCK_STREAM, 0))
+	host(host),
+	port(port)
 {
-	struct addrinfo hints, *res;
-	int status;
-	memset(&hints, 0, sizeof(hints));
-	hints.ai_family = AF_INET;
-	hints.ai_socktype = SOCK_STREAM;
-	char *host = "esp-942daf.local";
-	char *port = "5556";
-	status = getaddrinfo(host, port, &hints, &res)
 }
 
 disk_backend_nbd::~disk_backend_nbd()
@@ -29,6 +22,28 @@ disk_backend_nbd::~disk_backend_nbd()
 	close(fd);
 }
 
+bool disk_backend_nbd::begin()
+{
+	addrinfo *res   = nullptr;
+
+	addrinfo hints { 0 };
+	hints.ai_family = AF_INET;
+	hints.ai_socktype = SOCK_STREAM;
+
+	char port_str[8] { 0 };
+	snprintf(port_str, sizeof port_str, "%d", port);
+
+	int rc = getaddrinfo(host.c_str(), port_str, &hints, &res);
+
+	if (rc != 0) {
+		DOLOG(ll_error, true, "disk_backend_nbd: cannot resolve \"%s\":%s: %s", host.c_str(), port_str, gai_strerror(rc));
+
+		return false;
+	}
+
+	return true;
+}
+
 bool disk_backend_nbd::read(const off_t offset, const size_t n, uint8_t *const target)
 {
 	DOLOG(debug, false, "disk_backend_nbd::read: read %zu bytes from offset %zu", n, offset);

disk_backend_nbd.h

@@ -1,4 +1,7 @@
+#include <netdb.h>
 #include <string>
+#include <sys/socket.h>
+#include <sys/types.h>
 
 #include "disk_backend.h"
 
@@ -6,13 +9,17 @@
 class disk_backend_nbd : public disk_backend
 {
 private:
-	const int fd { -1 };
+	const std::string host;
+	const int         port;
+	int               fd   { -1 };
 
 public:
 	disk_backend_nbd(const std::string & host, const int port);
 	virtual ~disk_backend_nbd();
 
-	bool read(const off_t offset, const size_t n, uint8_t *const target);
+	bool begin() override;
 
-	bool write(const off_t offset, const size_t n, const uint8_t *const from);
+	bool read(const off_t offset, const size_t n, uint8_t *const target) override;
+
+	bool write(const off_t offset, const size_t n, const uint8_t *const from) override;
 };