apps/system/system: Add a generic system command. Current implentation cannot use /bin/sh and spawns the custom NSH system command directly.

system/system/.gitignore

@@ -0,0 +1,11 @@
+/Make.dep
+/.depend
+/.built
+/*.asm
+/*.rel
+/*.lst
+/*.sym
+/*.adb
+/*.lib
+/*.src
+/*.obj

system/system/Kconfig

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+#
+# For a description of the syntax of this configuration file,
+# see the file kconfig-language.txt in the NuttX tools repository.
+#
+
+config SYSTEM_SYSTEM
+	bool "System Command"
+	default n
+	depends on NSH_LIBRARY && SCHED_WAITPID
+	---help---
+		Enable support for the system() interface.  This will support
+		execution of NSH commands from C code.
+
+if SYSTEM_SYSTEM
+
+config SYSTEM_SYSTEM_STACKSIZE
+	int "system stack size"
+	default 1536
+	---help---
+		The size of stack allocated for the shell.
+
+config SYSTEM_SYSTEM_PRIORITY
+	int "system priority"
+	default 100
+	---help---
+		The priority of the shell.
+
+endif

system/system/Make.defs

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+############################################################################
+# apps/system/system/Make.defs
+# Adds selected applications to apps/ build
+#
+#   Copyright (C) 2016 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_SYSTEM_SYSTEM),y)
+CONFIGURED_APPS += system/system
+endif

system/system/Makefile

@@ -0,0 +1,102 @@
+############################################################################
+# apps/system/system/Makefile
+#
+#   Copyright (C) 2016 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.
+#
+############################################################################
+
+-include $(TOPDIR)/.config
+-include $(TOPDIR)/Make.defs
+include $(APPDIR)/Make.defs
+
+# system command
+
+ASRCS =
+CSRCS = system.c
+
+AOBJS = $(ASRCS:.S=$(OBJEXT))
+COBJS = $(CSRCS:.c=$(OBJEXT))
+
+SRCS = $(ASRCS) $(CSRCS) $(MAINSRC)
+OBJS = $(AOBJS) $(COBJS)
+
+ifeq ($(CONFIG_WINDOWS_NATIVE),y)
+  BIN = ..\..\libapps$(LIBEXT)
+else
+ifeq ($(WINTOOL),y)
+  BIN = ..\\..\\libapps$(LIBEXT)
+else
+  BIN = ../../libapps$(LIBEXT)
+endif
+endif
+
+ROOTDEPPATH = --dep-path .
+
+# Common build
+
+VPATH =
+
+all: .built
+.PHONY: install preconfig context depend clean distclean
+
+$(AOBJS): %$(OBJEXT): %.S
+	$(call ASSEMBLE, $<, $@)
+
+$(COBJS) $(MAINOBJ): %$(OBJEXT): %.c
+	$(call COMPILE, $<, $@)
+
+.built: $(OBJS)
+	$(call ARCHIVE, $(BIN), $(OBJS))
+	$(Q) touch .built
+
+install:
+
+preconfig:
+
+context:
+
+# Create dependencies
+
+.depend: Makefile $(SRCS)
+	$(Q) $(MKDEP) $(ROOTDEPPATH) "$(CC)" -- $(CFLAGS) -- $(SRCS) >Make.dep
+	$(Q) touch $@
+
+depend: .depend
+
+clean:
+	$(call DELFILE, .built)
+	$(call CLEAN)
+
+distclean: clean
+	$(call DELFILE, Make.dep)
+	$(call DELFILE, .depend)
+
+-include Make.dep

system/system/system.c

@@ -0,0 +1,105 @@
+/****************************************************************************
+ * apps/system/system/system.c
+ *
+ *   Copyright (C) 2016 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/wait.h>
+#include <stdlib.h>
+#include <sched.h>
+#include <assert.h>
+
+#include "nshlib/nshlib.h"
+
+/****************************************************************************
+ * Public Functions
+ ****************************************************************************/
+
+/****************************************************************************
+ * Name: system
+ *
+ * Description:
+ *   Use system to pass a command string to the NSH parser and wait for it
+ *   to finish executing.
+ *
+ *   This is an experimental version with known incompatibilies:
+ *
+ *   1. It is not a part of libc due to its close association with NSH.  The
+ *      function is still prototyped in nuttx/include/stdlib.h, however.
+ *   2. It cannot use /bin/sh since that program will not exist in most
+ *      embedded configurations.  Rather, it will spawn a shell-specific
+ *      system command -- currenly only NSH.
+ *   3. REVISIT: There may be some issues with returned values.
+ *   4. Of course, only NSH commands will be supported so that still means
+ *      that many leveraged system() calls will still not be functional.
+ *
+ ****************************************************************************/
+
+int system(FAR char *cmd)
+{
+  FAR char *nshargv[3];
+  int pid;
+  int rc;
+  int ret;
+
+  DEBUGASSERT(cmd != NULL);
+
+  /* Spawn nsh_system() which will execute the command under the shell */
+
+  nshargv[0] = "system";
+  nshargv[1] = cmd;
+  nshargv[2] = NULL;
+
+  pid = task_create("system", CONFIG_SYSTEM_SYSTEM_PRIORITY,
+                    CONFIG_SYSTEM_SYSTEM_STACKSIZE, nsh_system,
+                    (FAR char * const *)nshargv);
+  if (pid < 0)
+    {
+      return EXIT_FAILURE;
+    }
+
+  /* Wait for the shell to return */
+
+  ret = waitpid(pid, &rc, 0);
+  if (ret < 0)
+    {
+      return EXIT_FAILURE;
+    }
+
+  return rc;
+}