noux: close files marked with the 'close_on_execve' flag on 'execve()'

Fixes #2660

repos/ports/include/noux_session/sysio.h

@@ -155,7 +155,8 @@ struct Noux::Sysio
 	enum Fcntl_cmd {
 		FCNTL_CMD_GET_FILE_STATUS_FLAGS,
 		FCNTL_CMD_SET_FILE_STATUS_FLAGS,
-		FCNTL_CMD_SET_FD_FLAGS
+		FCNTL_CMD_SET_FD_FLAGS,
+		FCNTL_CMD_GET_FD_FLAGS
 	};
 
 	/**

repos/ports/src/lib/libc_noux/plugin.cc

@@ -1595,14 +1595,8 @@ namespace {
 			}
 
 		case F_GETFD:
-			/*
+			sysio()->fcntl_in.cmd = Noux::Sysio::FCNTL_CMD_GET_FD_FLAGS;
-			 * Normally, we would return the file-descriptor flags.
+			break;
-			 *
-			 * XXX: FD_CLOEXEC not yet supported
-			 */
-			if (verbose)
-				warning("fcntl(F_GETFD) not implemented, returning 0");
-			return 0;
 
 		case F_SETFD:
 			sysio()->fcntl_in.cmd      = Noux::Sysio::FCNTL_CMD_SET_FD_FLAGS;

repos/ports/src/noux/child.h

@@ -243,11 +243,15 @@ class Noux::Child : public Rpc_object<Session>,
 		/**
 		 * Let specified child inherit our file descriptors
 		 */
-		void _assign_io_channels_to(Child *child)
+		void _assign_io_channels_to(Child *child, bool skip_when_close_on_execve_set)
 		{
 			for (int fd = 0; fd < MAX_FILE_DESCRIPTORS; fd++)
-				if (fd_in_use(fd))
+				if (fd_in_use(fd)) {
+					if (skip_when_close_on_execve_set && close_fd_on_execve(fd))
+						continue;
 					child->add_io_channel(io_channel_by_fd(fd), fd);
+					child->close_fd_on_execve(fd, close_fd_on_execve(fd));
+				}
 		}
 
 		/**
@@ -536,7 +540,7 @@ class Noux::Child : public Rpc_object<Session>,
 			                                 false,
 			                                 _destruct_queue);
 
-			_assign_io_channels_to(child);
+			_assign_io_channels_to(child, true);
 
 			/* move the signal queue */
 			while (!_pending_signals.empty())

repos/ports/src/noux/file_descriptor_registry.h

@@ -30,6 +30,7 @@ class Noux::File_descriptor_registry
 
 		struct {
 			bool                       allocated;
+			bool                       close_on_execve;
 			Shared_pointer<Io_channel> io_channel;
 		} _fds[MAX_FILE_DESCRIPTORS];
 
@@ -51,14 +52,16 @@ class Noux::File_descriptor_registry
 
 		void _assign_fd(int fd, Shared_pointer<Io_channel> &io_channel)
 		{
-			_fds[fd].io_channel = io_channel;
+			_fds[fd].io_channel      = io_channel;
-			_fds[fd].allocated  = true;
+			_fds[fd].allocated       = true;
+			_fds[fd].close_on_execve = false;
 		}
 
 		void _reset_fd(int fd)
 		{
-			_fds[fd].io_channel = Shared_pointer<Io_channel>();
+			_fds[fd].io_channel      = Shared_pointer<Io_channel>();
-			_fds[fd].allocated  = false;
+			_fds[fd].allocated       = false;
+			_fds[fd].close_on_execve = false;
 		}
 
 	public:
@@ -110,6 +113,24 @@ class Noux::File_descriptor_registry
 			return _fds[fd].io_channel;
 		}
 
+		void close_fd_on_execve(int fd, bool close_on_execve)
+		{
+			if (!_valid_fd(fd))
+				error("file descriptor ", fd, " is out of range");
+			else
+				_fds[fd].close_on_execve = close_on_execve;
+		}
+
+		bool close_fd_on_execve(int fd)
+		{
+			if (!_valid_fd(fd)) {
+				error("file descriptor ", fd, " is out of range");
+				return false;
+			}
+
+			return _fds[fd].close_on_execve;
+		}
+
 		virtual void flush()
 		{
 			/* close all file descriptors */

repos/ports/src/noux/io_channel.h

@@ -68,10 +68,6 @@ class Noux::Io_channel : public Reference_counter
 
 	public:
 
-		bool close_on_execve;
-
-		Io_channel() : close_on_execve(false) { }
-
 		virtual ~Io_channel() { }
 
 		virtual Io_channel_backend *backend() { return nullptr; }

repos/ports/src/noux/syscall.cc

@@ -171,8 +171,15 @@ bool Noux::Child::syscall(Noux::Session::Syscall sc)
 			if (_sysio.fcntl_in.cmd == Sysio::FCNTL_CMD_SET_FD_FLAGS) {
 
 				/* we assume that there is only the close-on-execve flag */
-				_lookup_channel(_sysio.fcntl_in.fd)->close_on_execve =
+				close_fd_on_execve(_sysio.fcntl_in.fd, !!_sysio.fcntl_in.long_arg);
-					!!_sysio.fcntl_in.long_arg;
+				result = true;
+				break;
+			}
+
+			if (_sysio.fcntl_in.cmd == Sysio::FCNTL_CMD_GET_FD_FLAGS) {
+
+				/* we assume that there is only the close-on-execve flag */
+				_sysio.fcntl_out.result = close_fd_on_execve(_sysio.fcntl_in.fd);
 				result = true;
 				break;
 			}
@@ -556,7 +563,7 @@ bool Noux::Child::syscall(Noux::Session::Syscall sc)
 
 				Family_member::insert(child);
 
-				_assign_io_channels_to(child);
+				_assign_io_channels_to(child, false);
 
 				/* copy our address space into the new child */
 				try {