Squashed commit of the following:

   Author: anchao <anchao@pinecone.net>

     apps/, most main() function: Correct CONFIG_BUILD_LOADABLE usage
     Loadable apps/: Correct loadable symbol table generate
     apps/system/ubloxmodem:  Fix build break
     apps/examples/ostest: start restart/waitpid/user test from main loop
     apps/nshlib:  Expand reboot and poweroff commands to include a second, optional mode argument

    Author: Gregory Nutt <gnutt@nuttx.org>

     An attempt to fix build issues.  Does not work.
     apps/examples/ostest:  Fix some inappropriate renaming of static functions introduced with recent patches.
     apps/builtin/exec_builtin.c:  Fix a error introduced by recent comments.  Found in build testing.

    Author: anchao <anchao@pinecone.net>

     apps/builtin/exec_builtin.c:  Try posix_spawn if builtin apps do not have have an entry point.
     apps/Application.mk: introduce MODULE config to simplify tristate(m)
     apps/nsh:  Change the nuttx shell module type to tristate
     apps:  Add loadable application support
     script/mksymtab:  Generate symbol table name by default
     apps/builtin:  Allow loadable applications can register with apps/builtin.

Application.mk

@@ -37,8 +37,31 @@
 
 include $(APPDIR)/Make.defs
 
+# If this is an executable program (with MAINSRC), we must build it as a
+# loadable module for the KERNEL build (always) or if the tristate module
+# has the value "m"
+
+ifneq ($(MAINSRC),)
+  ifneq ($(MODULE),)
+    ifeq ($(CONFIG_$(MODULE)),m)
+      BUILD_MODULE = y
+    endif
+  endif
+endif
+
+# Pass the definition to the C/C++ code via the CFLAGS/CXXFLAGS
+
+ifeq ($(BUILD_MODULE),y)
+  CFLAGS += ${shell $(DEFINE) "$(CC)" BUILD_MODULE}
+  CXXFLAGS += ${shell $(DEFINE) "$(CC)" BUILD_MODULE}
+endif
+
+# File extensions
+
 CXXEXT ?= .cxx
 
+# Object files
+
 AOBJS = $(ASRCS:.S=$(OBJEXT))
 COBJS = $(CSRCS:.c=$(OBJEXT))
 CXXOBJS = $(CXXSRCS:$(CXXEXT)=$(OBJEXT))
@@ -52,10 +75,12 @@ endif
 SRCS = $(ASRCS) $(CSRCS) $(CXXSRCS) $(MAINSRC)
 OBJS = $(AOBJS) $(COBJS) $(CXXOBJS)
 
-ifneq ($(CONFIG_BUILD_KERNEL),y)
+ifneq ($(BUILD_MODULE),y)
   OBJS += $(MAINOBJ)
 endif
 
+# Module install directory
+
 ifeq ($(WINTOOL),y)
   BIN = "${shell cygpath -w $(APPDIR)$(DELIM)libapps$(LIBEXT)}"
   INSTALL_DIR = "${shell cygpath -w $(BIN_DIR)}"
@@ -68,6 +93,8 @@ ROOTDEPPATH = --dep-path .
 
 VPATH =
 
+# Targets follow
+
 all: .built
 .PHONY: clean preconfig depend distclean
 .PRECIOUS: $(APPDIR)/libapps$(LIBEXT)
@@ -89,18 +116,11 @@ $(MAINOBJ): %$(OBJEXT): %.c
 	$(call COMPILE, $<, $@)
 endif
 
-ifeq ($(LOADABLE),y)
-.built: $(OBJS)
-	$(call ELFLD, $(APPNAME)_main, $(OBJS), $(APPNAME))
-	$(Q) mkdir -p $(BIN_DIR)
-	$(Q) install $(APPNAME) $(BIN_DIR)$(DELIM)$(APPNAME)
-else
 .built: $(OBJS)
 	$(call ARCHIVE, $(BIN), $(OBJS))
 	$(Q) touch $@
-endif
 
-ifeq ($(CONFIG_BUILD_KERNEL),y)
+ifeq ($(BUILD_MODULE), y)
 $(BIN_DIR)$(DELIM)$(PROGNAME): $(OBJS) $(MAINOBJ)
 	@echo "LD: $(PROGNAME)"
 	$(Q) $(LD) $(LDELFFLAGS) $(LDLIBPATH) -o $(INSTALL_DIR)$(DELIM)$(PROGNAME) $(ARCHCRT0OBJ) $(MAINOBJ) $(LDLIBS)
@@ -118,7 +138,7 @@ ifneq ($(APPNAME),)
 ifneq ($(PRIORITY),)
 ifneq ($(STACKSIZE),)
 $(BUILTIN_REGISTRY)$(DELIM)$(APPNAME)_main.bdat: $(DEPCONFIG) Makefile
-	$(call REGISTER,$(APPNAME),$(PRIORITY),$(STACKSIZE),$(APPNAME)_main)
+	$(call REGISTER,$(APPNAME),$(PRIORITY),$(STACKSIZE),$(if $(BUILD_MODULE),,$(APPNAME)_main))
 
 context: $(BUILTIN_REGISTRY)$(DELIM)$(APPNAME)_main.bdat
 else
@@ -145,9 +165,6 @@ endif
 depend: .depend
 
 clean:
-ifeq ($(LOADABLE),y)
-	$(call DELFILE, $(APPNAME))
-endif
 	$(call DELFILE, .built)
 	$(call CLEAN)
 

Make.defs

@@ -43,46 +43,23 @@ DEPCONFIG = $(TOPDIR)$(DELIM).config
 ifeq ($(CONFIG_WINDOWS_NATIVE),y)
 define REGISTER
 	$(Q) echo Register: $1
-	$(Q) echo { "$1", $2, $3, $4 }, > "$(BUILTIN_REGISTRY)$(DELIM)$4.bdat"
-	$(Q) echo int $4(int argc, char *argv[]); > "$(BUILTIN_REGISTRY)$(DELIM)$4.pdat"
+	$(Q) echo { "$1", $2, $3, $4 }, > "$(BUILTIN_REGISTRY)$(DELIM)$1.bdat"
+	$(Q) if [ ! -z $4 ]; then \
+	        echo "int $4(int argc, char *argv[]);" > "$(BUILTIN_REGISTRY)$(DELIM)$1.pdat"; \
+	     fi;
 	$(Q) touch $(BUILTIN_REGISTRY)$(DELIM).updated"
 endef
 else
 define REGISTER
-	$(Q) echo "Register: $1"
-	$(Q) echo "{ \"$1\", $2, $3, $4 }," > "$(BUILTIN_REGISTRY)$(DELIM)$4.bdat"
-	$(Q) echo "int $4(int argc, char *argv[]);" > "$(BUILTIN_REGISTRY)$(DELIM)$4.pdat"
+	$(Q) echo "Register: $1  $4"
+	$(Q) echo "{ \"$1\", $2, $3, $4 }," > "$(BUILTIN_REGISTRY)$(DELIM)$1.bdat"
+	$(Q) if [ ! -z $4 ]; then \
+	        echo "int $4(int argc, char *argv[]);" > "$(BUILTIN_REGISTRY)$(DELIM)$1.pdat"; \
+	     fi;
 	$(Q) touch "$(BUILTIN_REGISTRY)$(DELIM).updated"
 endef
 endif
 
-# COMPILE - a macro to compile a loadable app in C
-
-ifeq ($(LOADABLE),y)
-define COMPILE
-	@echo "CC) $1"
-	$(Q) $(CC) -c $(CELFFLAGS) -DLOADABLE_APP $1 -o $2
-endef
-endif
-
-# COMPILEXX - a macro to compile a loadable app in C++
-
-ifeq ($(LOADABLE),y)
-define COMPILEXX
-	@echo "CXX: $1"
-	$(Q) $(CXX) -c $(CXXELFFLAGS) -DLOADABLE_APP $1 -o $2
-endef
-endif
-
-# ELFLD - a macro to link loadable app
-# Example: $(call ELFLD, entry point, in-file(s), out-file)
-
-define ELFLD
-	@echo "LD: $3"
-	$(Q) $(LD) $(LDELFFLAGS) $2 -o $3
-	$(Q) chmod +x $3
-endef
-
 # Tools
 #
 # In a normal build, tools will reside in the nuttx/tools sub-directory and
@@ -146,3 +123,4 @@ endif
 CFLAGS   += ${shell $(INCDIR) $(INCDIROPT) "$(CC)" "$(APPDIR)$(DELIM)include"}
 CXXFLAGS += ${shell $(INCDIR) $(INCDIROPT) "$(CC)" "$(APPDIR)$(DELIM)include"}
 
+LDLIBS = $(APPDIR)/libapps.a

Makefile

@@ -67,21 +67,22 @@ LIBPATH ?= $(TOPDIR)$(DELIM)staging
 
 # The install path
 
-BIN_DIR = $(APPDIR)$(DELIM)bin
+EXE_DIR = $(APPDIR)$(DELIM)exe
+BIN_DIR = $(EXE_DIR)$(DELIM)system$(DELIM)bin
 
 # The final build target
 
 BIN = libapps$(LIBEXT)
 
 # Symbol table for loadable apps.
 
-SYMTABSRC = $(APPDIR)$(DELIM)symtab_apps.c
-SYMTABOBJ = $(APPDIR)$(DELIM)symtab_apps$(OBJEXT)
+SYMTABSRC = $(EXE_DIR)$(DELIM)symtab_apps.c
+SYMTABOBJ = $(SYMTABSRC:.c=$(OBJEXT))
 
 # Build targets
 
 all: $(BIN)
-.PHONY: import symtab install dirlinks context context_serialize clean_context context_rest .depdirs preconfig depend clean distclean
+.PHONY: import install dirlinks context context_serialize clean_context context_rest .depdirs preconfig depend clean distclean
 .PRECIOUS: libapps$(LIBEXT)
 
 define MAKE_template
@@ -102,29 +103,29 @@ $(foreach SDIR, $(CONFIGURED_APPS), $(eval $(call SDIR_template,$(SDIR),depend))
 $(foreach SDIR, $(CLEANDIRS), $(eval $(call SDIR_template,$(SDIR),clean)))
 $(foreach SDIR, $(CLEANDIRS), $(eval $(call SDIR_template,$(SDIR),distclean)))
 
-make_symbols:
-ifeq ($(CONFIG_SYSTEM_NSH_SYMTAB),y)
-	mkdir -p $(BIN_DIR)
-	$(Q) $(APPDIR)$(DELIM)tools$(DELIM)mksymtab.sh $(BIN_DIR) $(SYMTABSRC)
-	$(call COMPILE, $(SYMTABSRC), $(SYMTABOBJ))
-	$(call ARCHIVE, $(APPDIR)$(DELIM)$(BIN), $(SYMTABOBJ))
-endif
+ifeq ($(CONFIG_BUILD_LOADABLE),)
+$(BIN): $(foreach SDIR, $(CONFIGURED_APPS), $(SDIR)_all)
+else
+$(SYMTABSRC): $(foreach SDIR, $(CONFIGURED_APPS), $(SDIR)_all)
+	$(Q) $(MAKE) install TOPDIR="$(TOPDIR)" APPDIR="$(APPDIR)"
+	$(Q) $(APPDIR)$(DELIM)tools$(DELIM)mksymtab.sh $(EXE_DIR)$(DELIM)system $(SYMTABSRC)
 
-$(BIN): $(foreach SDIR, $(CONFIGURED_APPS), $(SDIR)_all) make_symbols
+$(SYMTABOBJ): %$(OBJEXT): %.c
+	$(call COMPILE, -fno-lto $<, $@)
+
+$(BIN): $(SYMTABOBJ)
+	$(call ARCHIVE, $(BIN), $^)
+endif
 
 .install: $(foreach SDIR, $(CONFIGURED_APPS), $(SDIR)_install)
 
 $(BIN_DIR):
-	mkdir -p $(BIN_DIR)
+	$(Q) mkdir -p $(BIN_DIR)
 
 install: $(BIN_DIR) .install
 
 .import: $(BIN) install
 
-symtab: $(BIN_DIR)
-	$(Q) tools/mksymtab.sh $(BIN_DIR) $(APPDIR)$(DELIM)import/symtab.c
-	$(call MAKE_template,import,symtab)
-
 import:
 	$(Q) $(MAKE) .import TOPDIR="$(APPDIR)$(DELIM)import"
 

builtin/exec_builtin.c

@@ -181,11 +181,27 @@ int exec_builtin(FAR const char *appname, FAR char * const *argv,
         }
     }
 
-  /* Start the built-in */
+#ifdef CONFIG_LIBC_EXECFUNCS
+  /* A NULL entry point implies that the task is a loadable application */
+
+  if (builtin->main == NULL)
+    {
+      /* Load and execute the application. */
+
+      ret = posix_spawn(&pid, builtin->name, &file_actions,
+                        &attr, (argv) ? &argv[1] : (FAR char * const *)NULL,
+                        NULL);
+    }
+  else
+#endif
+    {
+      /* Start the built-in */
+
+      ret = task_spawn(&pid, builtin->name, builtin->main, &file_actions,
+                       &attr, (argv) ? &argv[1] : (FAR char * const *)NULL,
+                       (FAR char * const *)NULL);
+    }
 
-  ret = task_spawn(&pid, builtin->name, builtin->main, &file_actions,
-                   &attr, (argv) ? &argv[1] : (FAR char * const *)NULL,
-                   (FAR char * const *)NULL);
   if (ret != 0)
     {
       serr("ERROR: task_spawn failed: %d\n", ret);

examples/README.txt

@@ -79,7 +79,7 @@ examples/alarm
   Configuration:
 
     CONFIG_EXAMPLES_ALARM - Enable the RTC driver alarm test
-    CONFIG_EXAMPLES_ALARM_PROGNAME - If CONFIG_BUILD_KERNEL=y, then this is
+    CONFIG_EXAMPLES_ALARM_PROGNAME - If CONFIG_BUILD_LOADABLE=y, then this is
       the name of the program that will be use when the NSH ELF program is
       installed.
     CONFIG_EXAMPLES_ALARM_PRIORITY - Alarm daemon priority
@@ -435,7 +435,7 @@ examples/flash_test
     * CONFIG_MTD_SMART=y - SMART block driver support
     * CONFIG_NSH_BUILTIN_APPS=y - This example can only be built as an NSH
       command
-    * CONFIG_BUILD_PROTECTED=n and CONFIG_BUILD_KERNEL=n- This test uses
+    * CONFIG_BUILD_PROTECTED=n and CONFIG_BUILD_LOADABLE=n- This test uses
       internal OS interfaces and so is not available in the NUTTX kernel
       builds
 
@@ -1584,7 +1584,7 @@ examples/relays
   relies on internal OS interfaces that are not normally available to a
   user-space program.  As a result, this example cannot be used if a
   NuttX is built as a protected, supervisor kernel (CONFIG_BUILD_PROTECTED
-  or CONFIG_BUILD_KERNEL).
+  or CONFIG_BUILD_LOADABLE).
 
 examples/rfid_readuid
 ^^^^^^^^^^^^^^^^^^^^^

examples/adc/adc_main.c

@@ -228,7 +228,7 @@ static void parse_args(FAR struct adc_state_s *adc, int argc, FAR char **argv)
  * Name: adc_main
  ****************************************************************************/
 
-#ifdef CONFIG_BUILD_KERNEL
+#ifdef BUILD_MODULE
 int main(int argc, FAR char *argv[])
 #else
 int adc_main(int argc, char *argv[])

examples/adxl372_test/Kconfig

@@ -14,7 +14,7 @@ if EXAMPLES_ADXL372_TEST
 config EXAMPLES_ADXL372_TEST_PROGNAME
 	string "Program name"
 	default "ADXL372_test"
-	depends on BUILD_KERNEL
+	depends on BUILD_LOADABLE
 	---help---
 		This is the name of the program that will be use when the NSH ELF
 		program is installed.

examples/adxl372_test/adxl372_test_main.c

@@ -387,7 +387,7 @@ static int adxl372_test(int is_interactive, FAR char *path)
  *
  ****************************************************************************/
 
-#ifdef CONFIG_BUILD_KERNEL
+#ifdef BUILD_MODULE
 int main(int argc, FAR char *argv[])
 #else
 int adxl372_test_main(int argc, FAR char *argv[])

examples/ajoystick/ajoy_main.c

@@ -376,7 +376,7 @@ static int ajoy_calibrate(int fd)
  * ajoy_main
  ****************************************************************************/
 
-#ifdef CONFIG_BUILD_KERNEL
+#ifdef BUILD_MODULE
 int main(int argc, FAR char *argv[])
 #else
 int ajoy_main(int argc, char *argv[])

examples/alarm/Kconfig

@@ -15,7 +15,7 @@ if EXAMPLES_ALARM
 config EXAMPLES_ALARM_PROGNAME
 	string "Program name"
 	default "alarm"
-	depends on BUILD_KERNEL
+	depends on BUILD_LOADABLE
 	---help---
 		This is the name of the program that will be use when the NSH ELF
 		program is installed.

examples/alarm/alarm_main.c

@@ -208,7 +208,7 @@ static void show_usage(FAR const char *progname)
  * alarm_main
  ****************************************************************************/
 
-#ifdef CONFIG_BUILD_KERNEL
+#ifdef BUILD_MODULE
 int main(int argc, FAR char *argv[])
 #else
 int alarm_main(int argc, FAR char *argv[])

examples/apa102/Kconfig

@@ -14,7 +14,7 @@ if EXAMPLES_APA102
 config EXAMPLES_APA102_PROGNAME
 	string "Program name"
 	default "apa102"
-	depends on BUILD_KERNEL
+	depends on BUILD_LOADABLE
 	---help---
 		This is the name of the program that will be use when the NSH ELF
 		program is installed.

examples/apa102/apa102_main.c

@@ -150,7 +150,7 @@ static struct apa102_ledstrip_s hsvtorgb(uint16_t h, uint8_t s, uint8_t v)
  * apa102_main
  ****************************************************************************/
 
-#ifdef CONFIG_BUILD_KERNEL
+#ifdef BUILD_MODULE
 int main(int argc, FAR char *argv[])
 #else
 int apa102_main(int argc, char *argv[])

examples/apds9960/Kconfig

@@ -15,7 +15,7 @@ if EXAMPLES_APDS9960
 config EXAMPLES_APDS9960_PROGNAME
 	string "APDS-9960 Test Program name"
 	default "apds9960"
-	depends on BUILD_KERNEL
+	depends on BUILD_LOADABLE
 	---help---
 		This is the name of the program that will be use when the NSH ELF
 		program is installed.

examples/apds9960/apds9960_main.c

@@ -62,7 +62,7 @@
  * apds9960_main
  ****************************************************************************/
 
-#ifdef CONFIG_BUILD_KERNEL
+#ifdef BUILD_MODULE
 int main(int argc, FAR char *argv[])
 #else
 int apds9960_main(int argc, char *argv[])