nuttx/libs/libc/unistd/Kconfig

#
# For a description of the syntax of this configuration file,
# see the file kconfig-language.txt in the NuttX tools repository.
#

menu "Program Execution Options"

config LIBC_EXECFUNCS
	bool "Enable exec[l|v] / posix_spawn() Support"
	default n
	depends on !BINFMT_DISABLE
	---help---
		Enable support for the exec[l|v] family of functions that can be
		used to start other programs, terminating the current program and
		the posix_spawn() family of functions that can be used to start other
		programs without terminating the current program.  The typical
		usage of the exec[l|v] functions is (1) first call vfork() to create
		a new thread, then (2) call exec[l|v] to replace the new thread with
		a program from the file system.

		NOTE 1: This two step process start is completely unnecessary in
		NuttX and is provided only for compatibility with Unix systems.  These
		functions are essentially just wrapper functions that (1) call the
		non-standard binfmt function 'exec', and then (2) exit(0).  Since
		the new thread will be terminated by the exec[l|v] call, it really
		served no purpose other than to suport Unix compatility.

		The posix_spawn() functions do not have this inefficiency.

		NOTE 2: Support for exec[l|v] and posix_spawn() is conditional
		because they require additional support for symbol tables that
		will not be available in the typical system.

if LIBC_EXECFUNCS

config EXECFUNCS_HAVE_SYMTAB
	bool "Have symbol table"
	default n
	depends on !BUILD_KERNEL
	---help---
		If you have a system symbol table, then you may select this
		option in order to use it.  Symbol tables are required in most
		cases in order to link executable programs to the base code.

		NOTE: This option only pre-initializes the system symbol table as
		defined by CONFIG_EXECFUNCS_SYMTAB_ARRAY and CONFIG_EXECFUNCS_NSYMBOLS_VAR.
		This is simply an optional, automatic initialization of the
		system symbol table.  You would need to do this, for example, in
		in the kernel build were the first task must be run from a program
		on the file system.  This option has no other effect.

		Optionally, you can always call binfmt_setsymtab() from your
		board-specific logic or, equivalently, call boardctl(BOARDIOC_APP_SYMTAB)
		from your application initialization logic.

if EXECFUNCS_HAVE_SYMTAB

config EXECFUNCS_SYMTAB_ARRAY
	string "Symbol table name used by exec[l|v]"
	default "g_symtab"
	---help---
		The exec[l|v] and posix_spawn() functions are wrapper functions that
		call the non-standard binfmt function 'exec').  The binfmt
		function 'exec' needs to have (1) a symbol table that provides the
		list of symbols exported by the base code, and (2) the number of
		symbols in that table.  This selection provides the name of that
		symbol table.

config EXECFUNCS_NSYMBOLS_VAR
	string "Name of variable holding the number of symbols"
	default "g_nsymbols"
	---help---
		The exec[l|v] and posix_spawn() functions are wrapper functions that
		call the non-standard binfmt function 'exec').  The binfmt
		function 'exec' needs to have (1) a symbol table that provides the
		list of symbols exported by the base code, and (2) the number of
		symbols in that table.  This selection provides the name of an 'int'
		variable that contains the number of symbols in the symbol table.

config EXECFUNCS_SYSTEM_SYMTAB
	bool "Generate and include system symbol table"
	default n
	---help---
		Generate symbol table which includes symbols for all available
		syscalls, libc and libm functions. It makes system significantly
		larger but actual applications can reuse maximum from the system
		image.

		The symbol table array is named g_symtab and variable holding
		number of exported symbols g_nsymbols. It matches expected defaults
		from entries above. But they can be changed and generated symbol table
		can be used as template by application.

endif # EXECFUNCS_HAVE_SYMTAB
endif # LIBC_EXECFUNCS

config SYMTAB_ORDEREDBYNAME
	bool "Symbol Tables Ordered by Name"
	default n
	---help---
		Select if the symbol table is ordered by symbol name.  In this case,
		the logic can perform faster lookups using a binary search.
		Otherwise, the symbol table is assumed to be un-ordered and only
		slow, linear searches are supported.

config SYMTAB_ORDEREDBYVALUE
	bool "Symbol Tables Ordered by Value"
	default n
	---help---
		Select if the symbol table is ordered by symbol value.

config SYMTAB_DECORATED
	bool "Symbols are decorated with leading underscores"
	default n
	---help---
		Select if symbols in relocatable objects are decorated with a leading
		underscore. This option will remove the underscore from symbol names
		when relocating a loadable object.

config POSIX_SPAWN_PROXY_STACKSIZE
	int "Spawn Stack Size"
	default 1024
	---help---
		If posix_spawn[p]() and task_spawn() use I/O redirection options,
		they will require an intermediary/proxy task to muck with the file
		descriptors.  This configuration item specifies the stack size
		used for the proxy. Default: 1024 bytes.

config TASK_SPAWN_DEFAULT_STACKSIZE
	int "Default task_spawn Stack Size"
	default DEFAULT_TASK_STACKSIZE
	depends on !ARCH_ADDRENV
	---help---
		The actual size to use for the child task's stack can be set with
		task_spawnattr_setstacksize().  This value specifies the default
		stack size to use if task_spawnattr_setstacksize() is not used.
		Default: 2048.

endmenu # Program Execution Options

config LIBC_HOSTNAME
	string "Host name for this device"
	default ""
	---help---
		A unique name to identify device on the network

config LIBC_OPEN_MAX
	int "OPEN_MAX for this device"
	default 255
	---help---
		The maximum number of files that a process can have open
		at any time.  Must not be less than _POSIX_OPEN_MAX.