# # 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() familty of functions that can be used 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 compatibily 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 if !BUILD_KERNEL default y if 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. endif # EXECFUNCS_HAVE_SYMTAB endif # LIBC_EXECFUNCS 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 2048 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