Add support for a variadic ioctl() function. The ioctl() interface is a non-standard, Unix interface. NuttX has always used the older, three-parameter version. Most contemporary systems now, however, use a variadic form of the ioctl() function. Added an option to insert a shim layer to adapt the three-parameter ioctl() to use the variadic interface form. Internally, the ioctl handling is the same three-parameter logic. The only real complexity to the shim is in how the system calls must be handled.

3 files changed, 137 insertions, 0 deletions

diff --git a/nuttx/libc/Kconfig b/nuttx/libc/Kconfig
index 138793aad..2c31a1983 100644
--- a/nuttx/libc/Kconfig
+++ b/nuttx/libc/Kconfig
@@ -48,6 +48,32 @@ config LIBC_FLOATINGPOINT
 		By default, floating point
 		support in printf, sscanf, etc. is disabled.
 
+config LIBC_IOCTL_VARIADIC
+	bool "Enable variadic ioctl()"
+	default n
+	---help---
+		By default, NuttX implements the "old style," three-parameter,
+		ioctl() interface with this function prototype:
+
+			int ioctl(int fd, int req, unsigned long arg);
+
+		That function is implemented as part of the VFS.  If
+		LIBC_IOCTL_VARIADIC is selected, then an additional compatibility
+		layer will be provided in the C library.  The enabled, then function
+		prototype will become:
+
+			int ioctl(int fd, int req, ...);
+
+		The ioctl() is not controlled by any standard so it is really
+		arbitrary which format you used.  You may select the variadic
+		function prototype with this option.  That will slightly increase
+		code size and ioctl() processing time.  It will not support a
+		variable number of arguments and it still always expects to see a
+		third argument of type 'unsigned long'.  The only benefit of this
+		alternative function signature is that it may provide greater
+		compatibility if you are porting code from other platforms that use
+		the variadic ioctl() function.
+
 config LIB_RAND_ORDER
 	int "Order of the random number generate"
 	default 1
diff --git a/nuttx/libc/misc/Make.defs b/nuttx/libc/misc/Make.defs
index c09e78331..1e7a6ae05 100644
--- a/nuttx/libc/misc/Make.defs
+++ b/nuttx/libc/misc/Make.defs
@@ -42,18 +42,28 @@ CSRCS += lib_stream.c lib_filesem.c
 ifneq ($(CONFIG_NFILE_DESCRIPTORS),0)
 
 CSRCS += lib_sendfile.c
+
 ifneq ($(CONFIG_NFILE_STREAMS),0)
 CSRCS += lib_streamsem.c
 endif
 
+ifeq ($(CONFIG_LIBC_IOCTL_VARIADIC),y)
+CSRCS += lib_ioctl.c
+endif
+
 else
 ifneq ($(CONFIG_NSOCKET_DESCRIPTORS),0)
 
 CSRCS += lib_sendfile.c
+
 ifneq ($(CONFIG_NFILE_STREAMS),0)
 CSRCS += lib_streamsem.c
 endif
 
+ifeq ($(CONFIG_LIBC_IOCTL_VARIADIC),y)
+CSRCS += lib_ioctl.c
+endif
+
 endif
 endif
 
diff --git a/nuttx/libc/misc/lib_ioctl.c b/nuttx/libc/misc/lib_ioctl.c
new file mode 100644
index 000000000..9ef09fcd9
--- /dev/null
+++ b/nuttx/libc/misc/lib_ioctl.c
@@ -0,0 +1,101 @@
+/****************************************************************************
+ * libc/misc/lib_ioctl.c
+ *
+ *   Copyright (C) 2014 Gregory Nutt. All rights reserved.
+ *   Author: Gregory Nutt <gnutt@nuttx.org>
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright
+ *    notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ *    notice, this list of conditions and the following disclaimer in
+ *    the documentation and/or other materials provided with the
+ *    distribution.
+ * 3. Neither the name NuttX nor the names of its contributors may be
+ *    used to endorse or promote products derived from this software
+ *    without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
+ * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
+ * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+ * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
+ * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
+ * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
+ * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+ * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ * POSSIBILITY OF SUCH DAMAGE.
+ *
+ ****************************************************************************/
+
+/****************************************************************************
+ * Included Files
+ ****************************************************************************/
+
+#include <nuttx/config.h>
+
+#include <sys/ioctl.h>
+#include <stdarg.h>
+#include <errno.h>
+
+#include <nuttx/fs/fs.h>
+
+#include "lib_internal.h"
+
+#if defined(CONFIG_LIBC_IOCTL_VARIADIC) && CONFIG_NFILE_DESCRIPTORS > 0
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: ioctl/fs_ioctl
+ *
+ * Description:
+ *   Perform device specific operations.
+ *
+ * Parameters:
+ *   fd       File/socket descriptor of device
+ *   req      The ioctl command
+ *   ...      One argument of type unsigned long is expected
+ *
+ * Return:
+ *   >=0 on success (positive non-zero values are cmd-specific)
+ *   -1 on failure withi errno set properly:
+ *
+ *   EBADF
+ *     'fd' is not a valid descriptor.
+ *   EFAULT
+ *     'arg' references an inaccessible memory area.
+ *   EINVAL
+ *     'cmd' or 'arg' is not valid.
+ *   ENOTTY
+ *     'fd' is not associated with a character special device.
+ *   ENOTTY
+ *      The specified request does not apply to the kind of object that the
+ *      descriptor 'fd' references.
+ *
+ ****************************************************************************/
+
+int ioctl(int fd, int req, ...)
+{
+  va_list ap;
+  unsigned long arg;
+
+  /* Get the unsigned long argument */
+
+  va_start(ap, req);
+  arg = va_arg(ap, unsigned long );
+  va_end(ap);
+
+  /* Then let fs_ioctl() to the real work */
+
+  return fs_ioctl(fd, req, arg);
+}
+
+#endif /* CONFIG_LIBC_IOCTL_VARIADIC && CONFIG_NFILE_DESCRIPTORS > 0 */