fs/procfs: Add a tiny, primitive procfs file system. Might get more interesting in the future

ChangeLog

@@ -6040,3 +6040,5 @@
 	  apps/examples/i2schar test (2011-11-11).
 	* arch/arm/src/sama5/sam_ssc.c:  I2S loopback test finally works
 	  (2013-11-11).
+	* fs/procfs:  Add a little, primitive procfs file system. (2013-11-13).
+

Documentation/README.html

@@ -233,8 +233,10 @@
  |   |- fs/
  |   |   |- mmap/
  |   |   |   `- <a href="http://sourceforge.net/p/nuttx/git/ci/master/tree/nuttx/fs/mmap/README.txt"><b><i>README.txt</i></b></a>
- |   |   `- nxffs/
+ |   |   |- nxffs/
- |   |       `- <a href="http://sourceforge.net/p/nuttx/git/ci/master/tree/nuttx/fs/nxffs/README.txt"><b><i>README.txt</i></b></a>
+ |   |   |   `- <a href="http://sourceforge.net/p/nuttx/git/ci/master/tree/nuttx/fs/nxffs/README.txt"><b><i>README.txt</i></b></a>
+ |   |   `- procfs/
+ |   |       `- <a href="http://sourceforge.net/p/nuttx/git/ci/master/tree/nuttx/fs/procfs/README.txt"><b><i>README.txt</i></b></a>
  |   |- graphics/
  |   |   `- <a href="http://sourceforge.net/p/nuttx/git/ci/master/tree/nuttx/graphics/README.txt"><b><i>README.txt</i></b></a>
  |   |- lib/

README.txt

@@ -1161,7 +1161,9 @@ nuttx
  |- fs/
  |   |- mmap/
  |   |   `- README.txt
- |   `- nxffs/
+ |   |- nxffs/
+ |   |   `- README.txt
+ |   `- procfs/
  |       `- README.txt
  |- graphics/
  |   `- README.txt

fs/Kconfig

@@ -16,6 +16,7 @@ source fs/nxffs/Kconfig
 source fs/romfs/Kconfig
 source fs/smartfs/Kconfig
 source fs/binfs/Kconfig
+source fs/procfs/Kconfig
 
 comment "System Logging"
 

fs/Makefile

@@ -111,6 +111,7 @@ include nxffs/Make.defs
 include nfs/Make.defs
 include smartfs/Make.defs
 include binfs/Make.defs
+include procfs/Make.defs
 
 endif
 endif
@@ -122,7 +123,7 @@ OBJS	= $(AOBJS) $(COBJS)
 
 BIN		= libfs$(LIBEXT)
 
-SUBDIRS	= mmap fat romfs nxffs nfs binfs
+SUBDIRS	= mmap fat romfs nxffs nfs binfs procfs
 
 all:	$(BIN)
 

fs/fs_mount.c

@@ -63,7 +63,7 @@
 /* Configuration ************************************************************/
 /* In the canonical case, a file system is bound to a block driver.  However,
  * some less typical cases a block driver is not required.  Examples are
- * pseudo file systems (like BINFS) and MTD file systems (like NXFFS).
+ * pseudo file systems (like BINFS or PROCFS) and MTD file systems (like NXFFS).
  *
  * These file systems all require block drivers:
  */
@@ -74,7 +74,8 @@
 
 /* These file systems do not require block drivers */
 
-#if defined(CONFIG_FS_NXFFS) || defined(CONFIG_FS_BINFS) || defined(CONFIG_NFS) 
+#if defined(CONFIG_FS_NXFFS) || defined(CONFIG_FS_BINFS) || \
+    defined(CONFIG_FS_PROCFS) || defined(CONFIG_NFS)
 #  define NONBDFS_SUPPORT
 #endif
 
@@ -128,6 +129,9 @@ extern const struct mountpt_operations nfs_operations;
 #ifdef CONFIG_FS_BINFS
 extern const struct mountpt_operations binfs_operations;
 #endif
+#ifdef CONFIG_FS_PROCFS
+extern const struct mountpt_operations procfs_operations;
+#endif
 
 static const struct fsmap_t g_nonbdfsmap[] =
 {
@@ -140,7 +144,10 @@ static const struct fsmap_t g_nonbdfsmap[] =
 #ifdef CONFIG_FS_BINFS
     { "binfs", &binfs_operations },
 #endif
-    { NULL,   NULL },
+#ifdef CONFIG_FS_PROCFS
+    { "procfs", &procfs_operations },
+#endif
+    { NULL, NULL },
 };
 #endif /* NONBDFS_SUPPORT */
 

fs/procfs/Kconfig

@@ -0,0 +1,13 @@
+#
+# For a description of the syntax of this configuration file,
+# see misc/tools/kconfig-language.txt.
+#
+
+config FS_PROCFS
+	bool "PROCFS File System"
+	default n
+	---help---
+		The PROCFS file system is provides access to task status through the
+		NuttX file system.  The PROCFS may, for example, be mount at /proc.
+		Then information about all of the currently active tasks and threads
+		will be available in proc/.

fs/procfs/Make.defs

@@ -0,0 +1,48 @@
+############################################################################
+# fs/procfs/Make.defs
+#
+#   Copyright (C) 2013 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.
+#
+############################################################################
+
+ifeq ($(CONFIG_FS_PROCFS),y)
+# Files required for procfs file system support
+
+ASRCS +=
+CSRCS += fs_procfs.c
+
+# Include procfs build support
+
+DEPPATH += --dep-path procfs
+VPATH += :procfs
+CFLAGS += ${shell $(INCDIR) $(INCDIROPT) "$(CC)" $(TOPDIR)$(DELIM)fs$(DELIM)procfs}
+
+endif

fs/procfs/README.txt

@@ -0,0 +1,12 @@
+fs/procfs README
+================
+
+  This is a tiny procfs file system that allows read-only access to a few
+  attributes of a task or thread.  This tiny procfs fs file system can be
+  built into the system by enabling:
+
+    CONFIG_FS_PROCFS=y
+
+  It can then be mounted from the NSH command like like:
+
+    nsh> mount -t procfs /proc

include/nuttx/fs/dirent.h

@@ -196,6 +196,9 @@ struct fs_dirent_s
 #ifdef CONFIG_FS_BINFS
       struct fs_binfsdir_s   binfs;
 #endif
+#ifdef CONFIG_FS_PROCFS
+      FAR void              *procfs;
+#endif
 #ifdef CONFIG_FS_NXFFS
       struct fs_nxffsdir_s   nxffs;
 #endif

include/nuttx/sched.h

@@ -624,6 +624,10 @@ FAR struct tcb_s *sched_self(void);
 
 void sched_foreach(sched_foreach_t handler, FAR void *arg);
 
+/* Give a task ID, look up the corresponding TCB */
+
+FAR struct tcb_s *sched_gettcb(pid_t pid);
+
 /* File system helpers **********************************************************/
 /* These functions all extract lists from the group structure assocated with the
  * currently executing task.

include/sys/statfs.h

@@ -99,6 +99,7 @@
 /* NuttX specific file-systems */
 
 #define BINFS_MAGIC           0x4242
+#define PROCFS_MAGIC          0x434f5250
 #define NXFFS_MAGIC           0x4747
 #define SMARTFS_MAGIC         0x54524D53
 

sched/os_internal.h

@@ -258,7 +258,6 @@ int  sched_reprioritize(FAR struct tcb_s *tcb, int sched_priority);
 #else
 #  define sched_reprioritize(tcb,sched_priority) sched_setpriority(tcb,sched_priority)
 #endif
-FAR struct tcb_s *sched_gettcb(pid_t pid);
 bool sched_verifytcb(FAR struct tcb_s *tcb);
 
 int  sched_releasetcb(FAR struct tcb_s *tcb, uint8_t ttype);