Update logging around serial port operations, add locking on i/o

Author: janekbaraniewski

include/RealSerialPort.h

@@ -31,7 +31,7 @@ class RealSerialPort : public ISerialPort {
     }
 
     void async_read_some(const boost::asio::mutable_buffer& buffer, std::function<void(const boost::system::error_code&, std::size_t)> handler) override {
-        BOOST_LOG_TRIVIAL(info) << "Read some.";
+        // BOOST_LOG_TRIVIAL(info) << "Read some.";
         if (!port.is_open()) {
             BOOST_LOG_TRIVIAL(error) << "Attempt to read from a closed serial port.";
             return;

include/VirtualSerialPort.h

@@ -17,6 +17,7 @@ class VirtualSerialPort {
     boost::asio::posix::stream_descriptor master_fd_;
     std::array<char, 1024> read_buffer_;
     std::string device_name_;
+    std::mutex mutex_;
 
     void setup_pty(int fd);
 };

src/VirtualSerialPort.cpp

@@ -2,44 +2,52 @@
 
 VirtualSerialPort::VirtualSerialPort(boost::asio::io_context& io_context, const std::string& device)
     : master_fd_(io_context), device_name_("/dev/" + device) {
+    std::lock_guard<std::mutex> lock(mutex_);
     int master_fd = posix_openpt(O_RDWR | O_NOCTTY);
     if (master_fd == -1) {
         BOOST_LOG_TRIVIAL(error) << "Failed to open PTY master: " << strerror(errno);
         throw std::runtime_error("Failed to open PTY master");
     }
-    if (grantpt(master_fd) != 0 || unlockpt(master_fd) != 0) {
-        BOOST_LOG_TRIVIAL(error) << "Failed to grant or unlock PTY: " << strerror(errno);
-        throw std::runtime_error("Failed to grant or unlock PTY");
-    }
-
-    char* slave_name = ptsname(master_fd);
-    if (!slave_name) {
-        BOOST_LOG_TRIVIAL(error) << "Failed to get PTY slave name";
-        throw std::runtime_error("Failed to get PTY slave name");
-    }
-
-    if (unlink(device_name_.c_str()) == -1 && errno != ENOENT) {
-        BOOST_LOG_TRIVIAL(error) << "Failed to remove existing symlink: " << strerror(errno);
-        throw std::runtime_error("Failed to remove existing symlink");
-    }
-
-    if (symlink(slave_name, device_name_.c_str()) != 0) {
-        BOOST_LOG_TRIVIAL(error) << "Failed to create symlink for PTY slave: " << strerror(errno);
-        throw std::runtime_error("Failed to create symlink for PTY slave");
-    }
-
-    chmod(device_name_.c_str(), 0660);
-    struct group* tty_grp = getgrnam("tty");
-    if (tty_grp && chown(device_name_.c_str(), -1, tty_grp->gr_gid) == -1) {
-        BOOST_LOG_TRIVIAL(error) << "Failed to change group of device: " << strerror(errno);
-        throw std::runtime_error("Failed to change group of device");
-    }
-
-    master_fd_.assign(master_fd);
-    setup_pty(master_fd);
+        BOOST_LOG_TRIVIAL(info) << "PTY master opened successfully";
+
+        if (grantpt(master_fd) != 0 || unlockpt(master_fd) != 0) {
+            BOOST_LOG_TRIVIAL(error) << "Failed to grant or unlock PTY: " << strerror(errno);
+            throw std::runtime_error("Failed to grant or unlock PTY");
+        }
+        BOOST_LOG_TRIVIAL(info) << "PTY grant and unlock successful";
+
+        char* slave_name = ptsname(master_fd);
+        if (!slave_name) {
+            BOOST_LOG_TRIVIAL(error) << "Failed to get PTY slave name";
+            throw std::runtime_error("Failed to get PTY slave name");
+        }
+
+        if (unlink(device_name_.c_str()) == -1 && errno != ENOENT) {
+            BOOST_LOG_TRIVIAL(error) << "Failed to remove existing symlink: " << strerror(errno);
+            throw std::runtime_error("Failed to remove existing symlink");
+        }
+        BOOST_LOG_TRIVIAL(info) << "Existing symlink removed or not present";
+
+        if (symlink(slave_name, device_name_.c_str()) != 0) {
+            BOOST_LOG_TRIVIAL(error) << "Failed to create symlink for PTY slave: " << strerror(errno);
+            throw std::runtime_error("Failed to create symlink for PTY slave");
+        }
+        BOOST_LOG_TRIVIAL(info) << "Symlink for PTY slave created successfully";
+
+        chmod(device_name_.c_str(), 0660);
+        struct group* tty_grp = getgrnam("tty");
+        if (tty_grp && chown(device_name_.c_str(), -1, tty_grp->gr_gid) == -1) {
+            BOOST_LOG_TRIVIAL(error) << "Failed to change group of device: " << strerror(errno);
+            throw std::runtime_error("Failed to change group of device");
+        }
+        BOOST_LOG_TRIVIAL(info) << "Group changed successfully for the device";
+
+        master_fd_.assign(master_fd);
+        setup_pty(master_fd);
 }
 
 void VirtualSerialPort::setup_pty(int fd) {
+    std::lock_guard<std::mutex> lock(mutex_);
     struct termios tty;
     if (tcgetattr(fd, &tty) != 0) {
         BOOST_LOG_TRIVIAL(error) << "Error from tcgetattr: " << strerror(errno);
@@ -61,6 +69,8 @@ void VirtualSerialPort::setup_pty(int fd) {
 
     if (tcsetattr(fd, TCSANOW, &tty) != 0) {
         BOOST_LOG_TRIVIAL(error) << "Error from tcsetattr: " << strerror(errno);
+    } else {
+        BOOST_LOG_TRIVIAL(info) << "PTY attributes set successfully";
     }
 }
 
@@ -74,6 +84,7 @@ VirtualSerialPort::~VirtualSerialPort() {
 }
 
 void VirtualSerialPort::async_read(boost::asio::mutable_buffer buffer, std::function<void(const boost::system::error_code&, std::size_t)> handler) {
+    std::lock_guard<std::mutex> lock(mutex_);
     BOOST_LOG_TRIVIAL(info) << "VSP::async_read";
     boost::asio::async_read(master_fd_, buffer,
         [this, buffer, handler](const boost::system::error_code& ec, std::size_t length) {
@@ -97,6 +108,7 @@ void VirtualSerialPort::async_read(boost::asio::mutable_buffer buffer, std::func
 
 
 void VirtualSerialPort::async_write(boost::asio::const_buffer buffer, std::function<void(const boost::system::error_code&, std::size_t)> handler) {
+    std::lock_guard<std::mutex> lock(mutex_);
     std::string data(boost::asio::buffer_cast<const char*>(buffer), boost::asio::buffer_size(buffer));
     std::stringstream hex_stream;
     hex_stream << std::hex << std::setfill('0');