From 8f30804e05db1b6b9eab064e4bb621a26b612230 Mon Sep 17 00:00:00 2001
From: Gregory Nutt <gnutt@nuttx.org>
Date: Fri, 12 Sep 2014 12:48:22 -0600
Subject: [PATCH] Having a symbol table is an option.  There are no symbol
 tables with CONFIG_BUILD_KERNEL, for example.

---
 configs/sim/nsh/defconfig                      |  1 +
 configs/stm32f4discovery/posix_spawn/defconfig |  1 +
 libc/Kconfig                                   | 11 +++++++++++
 libc/unistd/lib_execsymtab.c                   |  7 +++++++
 4 files changed, 20 insertions(+)

diff --git a/configs/sim/nsh/defconfig b/configs/sim/nsh/defconfig
index 263a28303a..1523139b8b 100644
--- a/configs/sim/nsh/defconfig
+++ b/configs/sim/nsh/defconfig
@@ -409,6 +409,7 @@ CONFIG_LIB_RAND_ORDER=1
 # CONFIG_EOL_IS_BOTH_CRLF is not set
 CONFIG_EOL_IS_EITHER_CRLF=y
 CONFIG_LIBC_EXECFUNCS=y
+CONFIG_EXECFUNCS_HAVE_SYMTAB=y
 CONFIG_EXECFUNCS_SYMTAB="g_symtab"
 CONFIG_EXECFUNCS_NSYMBOLS=0
 CONFIG_POSIX_SPAWN_PROXY_STACKSIZE=1024
diff --git a/configs/stm32f4discovery/posix_spawn/defconfig b/configs/stm32f4discovery/posix_spawn/defconfig
index a8e0be0b55..ccce94eaf5 100644
--- a/configs/stm32f4discovery/posix_spawn/defconfig
+++ b/configs/stm32f4discovery/posix_spawn/defconfig
@@ -609,6 +609,7 @@ CONFIG_LIB_RAND_ORDER=1
 # CONFIG_EOL_IS_BOTH_CRLF is not set
 CONFIG_EOL_IS_EITHER_CRLF=y
 CONFIG_LIBC_EXECFUNCS=y
+CONFIG_EXECFUNCS_HAVE_SYMTAB=y
 CONFIG_EXECFUNCS_SYMTAB="exports"
 CONFIG_EXECFUNCS_NSYMBOLS=10
 CONFIG_POSIX_SPAWN_PROXY_STACKSIZE=1024
diff --git a/libc/Kconfig b/libc/Kconfig
index 79b7cbc0f6..e11e0a7ccc 100644
--- a/libc/Kconfig
+++ b/libc/Kconfig
@@ -107,6 +107,16 @@ config LIBC_EXECFUNCS
 
 if LIBC_EXECFUNCS
 
+config EXECFUNCS_HAVE_SYMTAB
+	bool "Have symbol table"
+	default n if BUILD_KERNEL
+	default y if !BUILD_KERNEL
+	---help---
+		If you have a system symbol table, then you must select this
+		option in order to use it.  Symbol tables are required in most
+		cases in order to like executable programs to the base code.
+
+if EXECFUNCS_HAVE_SYMTAB
 config EXECFUNCS_SYMTAB
 	string "Symbol table used by exec[l|v]"
 	default "g_symtab"
@@ -129,6 +139,7 @@ config EXECFUNCS_NSYMBOLS
 		symbols in that table.  This selection provides the number of
 		symbols in the symbol table.
 
+endif # EXECFUNCS_HAVE_SYMTAB
 endif # LIBC_EXECFUNCS
 
 config POSIX_SPAWN_PROXY_STACKSIZE
diff --git a/libc/unistd/lib_execsymtab.c b/libc/unistd/lib_execsymtab.c
index 34b798bb4a..35df4c059f 100644
--- a/libc/unistd/lib_execsymtab.c
+++ b/libc/unistd/lib_execsymtab.c
@@ -69,14 +69,21 @@
  * Public Variables
  ****************************************************************************/
 
+#ifdef CONFIG_EXECFUNCS_HAVE_SYMTAB
 extern const struct symtab_s CONFIG_EXECFUNCS_SYMTAB;
+#endif
 
 /****************************************************************************
  * Private Data
  ****************************************************************************/
 
+#ifdef CONFIG_EXECFUNCS_HAVE_SYMTAB
 static FAR const struct symtab_s *g_exec_symtab = &CONFIG_EXECFUNCS_SYMTAB;
 static int g_exec_nsymbols = CONFIG_EXECFUNCS_NSYMBOLS;
+#else
+static FAR const struct symtab_s *g_exec_symtab;
+static int g_exec_nsymbols;
+#endif
 
 /****************************************************************************
  * Public Functions