2 # For a description of the syntax of this configuration file,
3 # see extra/config/Kconfig-language.txt
6 mainmenu "uClibc-ng $VERSION C Library Configuration"
8 config DESIRED_TARGET_ARCH
17 prompt "Target Architecture"
18 default TARGET_alpha if DESIRED_TARGET_ARCH = "alpha"
19 default TARGET_arc if DESIRED_TARGET_ARCH = "arc"
20 default TARGET_arm if DESIRED_TARGET_ARCH = "arm"
21 default TARGET_avr32 if DESIRED_TARGET_ARCH = "avr32"
22 default TARGET_bfin if DESIRED_TARGET_ARCH = "bfin"
23 default TARGET_cris if DESIRED_TARGET_ARCH = "cris"
24 default TARGET_frv if DESIRED_TARGET_ARCH = "frv"
25 default TARGET_h8300 if DESIRED_TARGET_ARCH = "h8300"
26 default TARGET_hppa if DESIRED_TARGET_ARCH = "hppa"
27 default TARGET_i386 if DESIRED_TARGET_ARCH = "i386"
28 default TARGET_ia64 if DESIRED_TARGET_ARCH = "ia64"
29 default TARGET_lm32 if DESIRED_TARGET_ARCH = "lm32"
30 default TARGET_m68k if DESIRED_TARGET_ARCH = "m68k"
31 default TARGET_metag if DESIRED_TARGET_ARCH = "metag"
32 default TARGET_microblaze if DESIRED_TARGET_ARCH = "microblaze"
33 default TARGET_mips if DESIRED_TARGET_ARCH = "mips"
34 default TARGET_nds32 if DESIRED_TARGET_ARCH = "nds32"
35 default TARGET_nios2 if DESIRED_TARGET_ARCH = "nios2"
36 default TARGET_or1k if DESIRED_TARGET_ARCH = "or1k"
37 default TARGET_powerpc if DESIRED_TARGET_ARCH = "powerpc"
38 default TARGET_sh if DESIRED_TARGET_ARCH = "sh"
39 default TARGET_sparc if DESIRED_TARGET_ARCH = "sparc"
40 default TARGET_x86_64 if DESIRED_TARGET_ARCH = "x86_64"
41 default TARGET_xtensa if DESIRED_TARGET_ARCH = "xtensa"
43 The architecture of your target.
60 # someone could sync this tree:
61 # http://linux-c6x.org/git/?p=uClibc.git;a=summary
92 config TARGET_microblaze
107 config TARGET_powerpc
125 menu "Target Architecture Features and Options"
128 source "extra/Configs/Config.alpha"
132 source "extra/Configs/Config.arm"
136 source "extra/Configs/Config.avr32"
140 source "extra/Configs/Config.bfin"
144 source "extra/Configs/Config.cris"
148 source "extra/Configs/Config.frv"
152 source "extra/Configs/Config.h8300"
156 source "extra/Configs/Config.hppa"
160 source "extra/Configs/Config.i386"
164 source "extra/Configs/Config.ia64"
168 source "extra/Configs/Config.lm32"
172 source "extra/Configs/Config.m68k"
176 source "extra/Configs/Config.metag"
180 source "extra/Configs/Config.nds32"
184 source "extra/Configs/Config.nios2"
188 source "extra/Configs/Config.microblaze"
192 source "extra/Configs/Config.mips"
196 source "extra/Configs/Config.or1k"
200 source "extra/Configs/Config.powerpc"
204 source "extra/Configs/Config.sh"
208 source "extra/Configs/Config.sparc"
212 source "extra/Configs/Config.x86_64"
216 source "extra/Configs/Config.xtensa"
220 source "extra/Configs/Config.c6x"
224 source "extra/Configs/Config.arc"
227 config TARGET_SUBARCH
229 default "e500" if CONFIG_E500
230 default "classic" if CONFIG_CLASSIC
231 default "sh4" if CONFIG_SH4
232 default "sh4" if CONFIG_SH4A
233 default "" if CONFIG_386
234 default "i486" if CONFIG_486
235 default "i586" if CONFIG_586
236 default "i686" if CONFIG_686
237 default "arcv2" if CONFIG_ARC_CPU_HS
240 source "extra/Configs/Config.in.arch"
244 menu "General Library Settings"
250 bool "Generate only Position Independent Code (PIC)"
252 depends on !HAVE_NO_PIC
254 If you wish to build all of uClibc as PIC objects, then answer Y here.
255 If you are unsure, then you should answer N.
257 config ARCH_HAS_NO_SHARED
260 config ARCH_HAS_NO_LDSO
262 select ARCH_HAS_NO_SHARED
264 config ARCH_HAS_UCONTEXT
268 bool "Enable shared libraries"
269 depends on !ARCH_HAS_NO_SHARED
272 If you wish to build uClibc with support for shared libraries then
273 answer Y here. If you only want to build uClibc as a static library,
276 config FORCE_SHAREABLE_TEXT_SEGMENTS
277 bool "Only load shared libraries which can share their text segment"
278 depends on HAVE_SHARED
281 If you answer Y here, the uClibc native shared library loader will
282 only load shared libraries, which do not need to modify any
283 non-writable segments. These libraries haven't set the DT_TEXTREL
284 tag in the dynamic section (==> objdump).
285 All your libraries must be compiled with -fPIC or -fpic, and all
286 assembler function must be written as position independent code (PIC).
287 Enabling this option will make uClibc's shared library loader a
288 little bit smaller and guarantee that no memory will be wasted by
289 badly coded shared libraries.
291 config LDSO_LDD_SUPPORT
292 bool "Native 'ldd' support"
293 depends on HAVE_SHARED
296 Enable all the code needed to support traditional ldd,
297 which executes the shared library loader to resolve all dependencies
298 and then provide a list of shared libraries that are required for an
299 application to function. Disabling this option will make uClibc's
300 shared library loader a little bit smaller.
301 Most people will answer Y.
303 config LDSO_CACHE_SUPPORT
304 bool "Enable library loader cache (ld.so.conf)"
305 depends on HAVE_SHARED
308 Enable this to make use of /etc/ld.so.conf, the shared library loader
309 cache configuration file to support for non-standard library paths.
310 After updating this file, it is necessary to run 'ldconfig' to update
311 the /etc/ld.so.cache shared library loader cache file.
313 config LDSO_PRELOAD_ENV_SUPPORT
314 bool "Enable library loader LD_PRELOAD environment"
315 depends on HAVE_SHARED
318 Enable this to make use of LD_PRELOAD environment variable.
319 A whitespace-separated list of additional, user-specified, ELF shared
320 libraries to be loaded before all others. This can be used to
321 selectively override functions in other shared libraries. For
322 set-user-ID/set-group-ID ELF binaries, only libraries in the standard
323 search directories that are also set-user-ID will be loaded.
325 config LDSO_PRELOAD_FILE_SUPPORT
326 bool "Enable library loader preload file (ld.so.preload)"
327 depends on HAVE_SHARED
329 Enable this to make use of /etc/ld.so.preload. This file contains a
330 whitespace separated list of shared libraries to be loaded before
333 config LDSO_BASE_FILENAME
334 string "Shared library loader naming prefix"
335 depends on HAVE_SHARED && (LDSO_CACHE_SUPPORT || LDSO_PRELOAD_FILE_SUPPORT)
338 If you wish to support both uClibc and glibc on the same system, it
339 is necessary to set this to something other than "ld.so" to avoid
340 conflicts with glibc, which also uses "ld.so". This prevents both
341 libraries from using the same /etc/ld.so.* files. If you wish to
342 support both uClibc and glibc on the same system then you should set
343 this to "ld-uClibc.so".
345 Most people will leave this set to the default of "ld.so".
347 WARNING: Changing the default prefix could cause problems with
350 config LDSO_STANDALONE_SUPPORT
351 bool "Dynamic linker stand-alone mode support"
352 depends on HAVE_SHARED
354 The dynamic linker can be run either indirectly through running some
355 dynamically linked program or library (in which case no command line
356 options to the dynamic linker can be passed and, in the ELF case, the
357 dynamic linker which is stored in the .interp section of the program
358 is executed) or directly by running:
360 /lib/ld-uClibc.so.* [OPTIONS] [PROGRAM [ARGUMENTS]]
362 Stand-alone execution is a prerequisite for adding prelink
363 capabilities to uClibc dynamic linker, as well useful for testing an
364 updated version of the dynamic linker without breaking the system.
366 config LDSO_PRELINK_SUPPORT
367 bool "Dynamic linker prelink support"
368 depends on HAVE_SHARED
369 select LDSO_STANDALONE_SUPPORT
371 The dynamic linker can be used in stand-alone mode by the prelink tool
372 for prelinking ELF shared libraries and binaries to speed up startup
373 time. It also is able to load and handle prelinked libraries and
376 config UCLIBC_STATIC_LDCONFIG
377 bool "Link ldconfig statically"
378 depends on HAVE_SHARED
381 Enable this option to statically link the ldconfig binary.
383 Making ldconfig static can be beneficial if you have a library
384 problem and need to use ldconfig to recover. Sometimes it is
385 preferable to instead keep the size of the system down, in which
386 case you should disable this option.
389 bool "Enable ELF RUNPATH tag support"
390 depends on HAVE_SHARED
391 default y if LDSO_CACHE_SUPPORT
393 ELF's may have dynamic RPATH/RUNPATH tags. These tags list paths
394 which extend the library search paths. They are really only useful
395 if a package installs libraries in non standard locations and
396 ld.so.conf support is disabled.
398 Usage of RUNPATH tags is not too common, so disabling this feature
399 should be safe for most people.
401 config LDSO_RUNPATH_OF_EXECUTABLE
402 bool "Use executables RUNPATH/RPATH when searching for libraries."
403 depends on LDSO_RUNPATH
406 Use the executables RUNPATH/RPATH to find to find libraries even
407 though this behavour is not standard. Setting this option causes
408 the uclibc dynamic linker behavour to match the glibc dynamic linker.
410 config LDSO_SAFE_RUNPATH
411 bool "Allow only RUNPATH beginning with /"
412 depends on LDSO_RUNPATH
415 Allow only absolute path in RPATH/RUNPATH.
417 config LDSO_SEARCH_INTERP_PATH
418 bool "Add ldso path to lib search path"
419 depends on HAVE_SHARED
422 The ldso is told where it is being executed from and can use that
423 path to find related core libraries. This is useful by default,
424 but can be annoying in a mixed development environment.
426 i.e. if the ldso is run from /foo/boo/ldso.so, it will start its
427 library search with /foo/boo/
429 If unsure, simply say Y here.
431 config LDSO_LD_LIBRARY_PATH
432 bool "Add LD_LIBRARY_PATH to lib search path"
433 depends on HAVE_SHARED
436 On hardened system it could be useful to disable the use of
437 LD_LIBRARY_PATH environment variable (a colon-separated list of
438 directories in which to search for ELF libraries at execution-time).
440 If unsure, simply say Y here.
442 config LDSO_NO_CLEANUP
443 bool "Disable automatic unloading of dynamically loaded shared objects"
444 depends on HAVE_SHARED
446 If you need complete allocation traces when debugging memory leaks
447 using Valgrind in a process that dynamically loads shared objects,
448 then answer Y here. Unlike glibc, uClibc unloads all dynamically
449 loaded shared objects when a process exits, which prevents Valgrind
450 from correctly resolving the symbols from the unloaded shared objects.
451 Unless you know you need this, you should answer N.
453 config UCLIBC_CTOR_DTOR
457 If you wish to build uClibc with support for global constructor
458 (ctor) and global destructor (dtor) support, then answer Y here.
459 When ctor/dtor support is enabled, binaries linked with uClibc must
460 also be linked with crtbegin.o and crtend.o which are provided by gcc
461 (the "*startfile:" and "*endfile:" settings in your gcc specs file
462 may need to be adjusted to include these files). This support will
463 also add a small amount of additional size to each binary compiled vs
464 uClibc. If you will be using uClibc with C++, or if you need the gcc
465 __attribute__((constructor)) and __attribute__((destructor)) to work,
466 then you definitely want to answer Y here. If you don't need ctors
467 or dtors and want your binaries to be as small as possible, then
470 config LDSO_GNU_HASH_SUPPORT
471 bool "Enable GNU hash style support"
472 depends on HAVE_SHARED
474 Newest binutils support a new hash style named GNU-hash. The dynamic
475 linker will use the new GNU-hash section (.gnu.hash) for symbol lookup
476 if present into the ELF binaries, otherwise it will use the old SysV
477 hash style (.hash). This ensures that it is completely backward
479 Further, being the hash table implementation self-contained into each
480 executable and shared libraries, objects with mixed hash style can
481 peacefully coexist in the same process.
483 If you want to use this new feature, answer Y
486 prompt "Thread support"
487 default HAS_NO_THREADS
489 If you want to compile uClibc with pthread support, then answer Y.
490 This will increase the size of uClibc by adding a bunch of locking
491 to critical data structures, and adding extra code to ensure that
492 functions are properly reentrant.
494 config HAS_NO_THREADS
497 Disable thread support.
499 config UCLIBC_HAS_LINUXTHREADS
501 # linuxthreads need nanosleep()
502 select UCLIBC_HAS_REALTIME
503 depends on !TARGET_metag
505 If you want to compile uClibc with Linuxthreads support, then answer Y.
507 config UCLIBC_HAS_THREADS_NATIVE
508 bool "Native POSIX Threading (NPTL)"
509 select UCLIBC_HAS_TLS
510 select UCLIBC_HAS_STDIO_FUTEXES
511 select UCLIBC_HAS_REALTIME
512 # i386 has no lowlevellock support (yet) as opposed to i486 onward
513 depends on !CONFIG_386 && \
528 If you want to compile uClibc with NPTL support, then answer Y.
532 config UCLIBC_HAS_THREADS
533 def_bool y if !HAS_NO_THREADS
535 config UCLIBC_HAS_TLS
536 bool "Thread-Local Storage"
537 depends on UCLIBC_HAS_THREADS_NATIVE
539 If you want to enable TLS support then answer Y.
540 This is fast an efficient way to store per-thread local data
541 which is not on stack. It needs __thread support enabled in
544 config PTHREADS_DEBUG_SUPPORT
545 bool "Build pthreads debugging support"
546 depends on UCLIBC_HAS_THREADS
548 Say Y here if you wish to be able to debug applications that use
549 uClibc's pthreads library. By enabling this option, a library
550 named libthread_db will be built. This library will be dlopen()'d
551 by gdb and will allow gdb to debug the threads in your application.
553 IMPORTANT NOTE! Because gdb must dlopen() the libthread_db library,
554 you must compile gdb with uClibc in order for pthread debugging to
557 If you are doing development and want to debug applications using
558 uClibc's pthread library, answer Y. Otherwise, answer N.
561 config UCLIBC_HAS_SYSLOG
562 bool "Syslog support"
564 depends on UCLIBC_HAS_NETWORK_SUPPORT
565 select UCLIBC_HAS_SOCKET
567 Support sending messages to the system logger.
568 This requires socket-support.
571 prompt "Malloc Implementation"
572 default MALLOC if ! ARCH_USE_MMU
573 default MALLOC_STANDARD if ARCH_USE_MMU
578 "malloc" use mmap for all allocations and so works very well on
579 MMU-less systems that do not support the brk() system call. It is
580 pretty smart about reusing already allocated memory, and minimizing
582 This is the default for uClinux MMU-less systems.
587 "malloc-simple" is trivially simple and slow as molasses. It
588 was written from scratch for uClibc, and is the simplest possible
589 (and therefore smallest) malloc implementation.
591 This uses only the mmap() system call to allocate and free memory,
592 and does not use the brk() system call at all, making it a fine
593 choice for MMU-less systems with very limited memory. It's 100%
594 standards compliant, thread safe, very small, and releases freed
595 memory back to the OS immediately rather than keeping it in the
596 process's heap for reallocation. It is also VERY SLOW.
598 config MALLOC_STANDARD
599 bool "malloc-standard"
600 depends on ARCH_USE_MMU
602 "malloc-standard" is derived from the public domain dlmalloc
603 implementation by Doug Lea. It is quite fast, and is pretty smart
604 about reusing already allocated memory, and minimizing memory
605 wastage. This uses brk() for small allocations, while using mmap()
606 for larger allocations. This is the default malloc implementation
609 If unsure, answer "malloc-standard".
613 config UCLIBC_DYNAMIC_ATEXIT
614 bool "Dynamic atexit() Support"
617 When this option is enabled, uClibc will support an infinite number,
618 of atexit() and on_exit() functions, limited only by your available
619 memory. This can be important when uClibc is used with C++, since
620 global destructors are implemented via atexit(), and it is quite
621 possible to exceed the default number when this option is disabled.
622 Enabling this option adds a few bytes, and more significantly makes
623 atexit and on_exit depend on malloc, which can be bad when compiling
626 Unless you use uClibc with C++, you should probably answer N.
629 bool "Old (visible) atexit Support"
631 Enable this option if you want to update from 0.9.28 to git/0.9.29,
632 else you will be missing atexit() until you rebuild all apps.
634 config UCLIBC_HAS_UTMPX
635 bool "utmpx based support for tracking login/logouts to/from the system"
637 Answer y to enable support for accessing user accounting database.
638 It can be used to track all login/logout to the system.
640 config UCLIBC_HAS_UTMP
641 bool "utmp support (XPG2 compat, SVr4 compat)"
642 depends on UCLIBC_HAS_UTMPX
644 Answer y to enable legacy SVID support for accessing
645 user accounting database:
646 getutent(), getutid(), getutline(), pututline(),
647 setutent(), endutent(), utmpname() in utmp.h
648 It can be used to track all login/logout to the system.
650 If unsure, answer N and use corresponding POSIX functions
653 config UCLIBC_SUSV2_LEGACY
654 bool "Enable SuSv2 LEGACY functions"
656 Enable this option if you want to have SuSv2 LEGACY functions
657 Currently applies to:
661 WARNING! ABI incompatibility.
663 config UCLIBC_SUSV3_LEGACY
664 bool "Enable SuSv3 LEGACY functions"
670 Enable this option if you want to have SuSv3 LEGACY functions
671 in the library, else they are replaced by SuSv3 proposed macros.
672 Currently applies to:
674 bcmp, bcopy, bzero, index, rindex, ftime,
675 bsd_signal, (ecvt), (fcvt), gcvt, (getcontext),
676 (getwd), (makecontext),
677 mktemp, (pthread_attr_getstackaddr), (pthread_attr_setstackaddr),
678 scalb, (setcontext), (swapcontext), ualarm, usleep,
681 WARNING! ABI incompatibility.
683 config UCLIBC_HAS_CONTEXT_FUNCS
684 bool "Use obsolescent context control functions"
685 depends on UCLIBC_SUSV3_LEGACY && ARCH_HAS_UCONTEXT
687 Add into library the SuSv3 obsolescent functions used for context
688 control. The setcontext family allows the implementation in C of
689 advanced control flow patterns such as iterators, fibers, and
690 coroutines. They may be viewed as an advanced version of
691 setjmp/longjmp; whereas the latter allows only a single non-local jump
692 up the stack, setcontext allows the creation of multiple cooperative
693 threads of control, each with its own stack.
694 These functions are: setcontext, getcontext, makecontext, swapcontext.
696 config UCLIBC_SUSV3_LEGACY_MACROS
697 bool "Enable SuSv3 LEGACY macros"
699 Enable this option if you want to have SuSv3 LEGACY macros.
700 Currently applies to bcopy/bzero/bcmp/index/rindex et al.
701 WARNING! ABI incompatibility.
703 config UCLIBC_SUSV4_LEGACY
704 bool "Enable SuSv4 LEGACY or obsolescent functions"
706 Enable this option if you want to have SuSv4 LEGACY functions
707 and macros in the library.
708 Currently applies to:
711 _longjmp, _setjmp, _tolower, _toupper, ftw, getitimer,
712 gettimeofday, isascii, pthread_getconcurrency,
713 pthread_setconcurrency, setitimer, setpgrp, sighold,
714 sigignore, sigpause, sigrelse, sigset, siginterrupt,
715 tempnam, toascii, ulimit.
718 asctime, asctime_r, ctime, ctime_r, gets, rand_r,
721 WARNING! ABI incompatibility.
723 config UCLIBC_STRICT_HEADERS
724 bool "Hide structures and constants for unsupported features"
726 Hide structures and constants in headers that should not be used,
727 because the respective feature is disabled.
729 WARNING! enabling this option requires to patch many faulty apps,
730 since they make (wrongly) use of these structures/constants,
731 although the feature was disabled.
733 config UCLIBC_HAS_STUBS
734 bool "Provide stubs for unavailable functionality"
736 With this option uClibc provides non-functional stubs for
737 functions which are impossible to implement on the target
738 architecture. Otherwise, such functions are simply omitted.
740 config UCLIBC_HAS_SHADOW
741 bool "Shadow Password Support"
744 Answer N if you do not need shadow password support.
745 Most people will answer Y.
747 config UCLIBC_HAS_PROGRAM_INVOCATION_NAME
748 bool "Support for program_invocation_name"
750 Support for the GNU-specific program_invocation_name and
751 program_invocation_short_name strings. Some GNU packages
752 (like tar and coreutils) utilize these for extra useful
753 output, but in general are not required.
755 At startup, these external strings are automatically set
756 up based on the value of ARGV[0].
758 If unsure, just answer N.
760 config UCLIBC_HAS___PROGNAME
761 bool "Support for __progname"
764 Some packages (like openssh) like to peek into internal libc
765 symbols to make their output a bit more user friendly.
767 At startup, __progname is automatically set up based on the
770 If unsure, just answer N.
772 config UCLIBC_HAS_PTY
773 bool "Support for pseudo-terminals"
776 This enables support for pseudo-terminals (see man 4 pts
779 If unsure, just answer Y.
782 bool "Assume that /dev/pts is a devpts or devfs file system"
784 depends on UCLIBC_HAS_PTY
786 Enable this if /dev/pts is on a devpts or devfs filesystem. Both
787 these filesystems automatically manage permissions on the /dev/pts
788 devices. You may need to mount your devpts or devfs filesystem on
789 /dev/pts for this to work.
791 Most people should answer Y.
793 config UNIX98PTY_ONLY
794 bool "Support only Unix 98 PTYs"
796 depends on UCLIBC_HAS_PTY
798 If you want to support only Unix 98 PTYs enable this. Some older
799 applications may need this disabled and will thus use legacy BSD
800 style PTY handling which is more complex and also bigger than
801 Unix 98 PTY handling.
803 For most current programs, you can generally answer Y.
806 config UCLIBC_HAS_GETPT
807 bool "Support getpt() (glibc-compat)"
808 depends on UCLIBC_HAS_PTY
810 Some packages may need getpt().
811 All of those are non-standard and can be considered
812 GNU/libc compatibility.
813 Either use posix_openpt() or just open /dev/ptmx yourself.
815 If unsure, just say N.
819 # Have to use __libc_ptyname{1,2}[] and related bloat
820 config UCLIBC_HAS_GETPT
824 config UCLIBC_HAS_LIBUTIL
825 bool "Provide libutil library and functions"
826 depends on UCLIBC_HAS_PTY
828 Provide a libutil library.
829 This non-standard conforming library provides the following
832 forkpty(): combines openpty(), fork(2), and login_tty() to
833 create a new process operating in a pseudo-terminal.
834 login(): write utmp and wtmp entries
835 login_tty(): prepares for a login on the tty fd by creating a
836 new session, making fd the controlling terminal for
837 the calling process, setting fd to be the standard
838 input, output, and error streams of the current
839 process, and closing fd.
840 logout(): write utmp and wtmp entries
841 logwtmp(): constructs a utmp structure and calls updwtmp() to
842 append the structure to the utmp file.
843 openpty(): finds an available pseudo-terminal and returns
844 file descriptors for the master and slave
846 This library adds about 3k-4k to your system.
848 config UCLIBC_HAS_TM_EXTENSIONS
849 bool "Support 'struct tm' timezone extension fields"
852 Enabling this option adds fields to 'struct tm' in time.h for
853 tracking the number of seconds east of UTC, and an abbreviation for
854 the current timezone. These fields are not specified by the SuSv3
855 standard, but they are commonly used in both GNU and BSD application
858 To strictly follow the SuSv3 standard, leave this disabled.
859 Most people will probably want to answer Y.
861 config UCLIBC_HAS_TZ_CACHING
862 bool "Enable caching of the last valid timezone 'TZ' string"
865 Answer Y to enable caching of the last valid 'TZ' string describing
866 the timezone setting. This allows a quick string compare to avoid
867 repeated parsing of unchanged 'TZ' strings when tzset() is called.
869 Most people will answer Y.
871 config UCLIBC_HAS_TZ_FILE
872 bool "Enable '/etc/TZ' file support to set a default timezone (uClibc-specific)"
875 Answer Y to enable the setting of a default timezone for uClibc.
877 Ordinarily, uClibc gets the timezone information exclusively from the
878 'TZ' environment variable. In particular, there is no support for
879 the zoneinfo directory tree or the /etc/timezone file used by glibc.
881 With this option enabled, uClibc will use the value stored in the
882 file '/etc/TZ' (default path) to obtain timezone information if the
883 'TZ' environment variable is missing or has an invalid value. The
884 file consists of a single line (newline required) of text describing
885 the timezone in the format specified for the TZ environment variable.
887 Doing 'echo CST6CDT > /etc/TZ' is enough to create a valid file.
889 http://www.opengroup.org/onlinepubs/007904975/basedefs/xbd_chap08.html
890 for details on valid settings of 'TZ'.
892 Most people will answer Y.
894 config UCLIBC_HAS_TZ_FILE_READ_MANY
895 bool "Repeatedly read the '/etc/TZ' file"
896 depends on UCLIBC_HAS_TZ_FILE
899 Answer Y to enable repeated reading of the '/etc/TZ' file even after
900 a valid value has been read. This incurs the overhead of an
901 open/read/close for each tzset() call (explicit or implied). However,
902 setting this will allow applications to update their timezone
903 information if the contents of the file change.
905 Most people will answer Y.
907 config UCLIBC_TZ_FILE_PATH
908 string "Path to the 'TZ' file for setting the global timezone"
909 depends on UCLIBC_HAS_TZ_FILE
912 This is the path to the 'TZ' file.
914 Most people will use the default of '/etc/TZ'.
916 config UCLIBC_FALLBACK_TO_ETC_LOCALTIME
917 bool "Use /etc/localtime as a fallback"
918 depends on UCLIBC_HAS_TZ_FILE
921 Answer Y to try to use /etc/localtime file.
922 On glibc systems this file (if it is in TZif2 format)
923 contains timezone string at the end.
925 Most people will answer Y.
929 menu "Advanced Library Settings"
931 config UCLIBC_PWD_BUFFER_SIZE
932 int "Buffer size for getpwnam() and friends"
936 This sets the value of the buffer size for getpwnam() and friends.
937 By default, this is 256. (For reference, glibc uses 1024).
938 The value can be found using sysconf() with the _SC_GETPW_R_SIZE_MAX
941 config UCLIBC_GRP_BUFFER_SIZE
942 int "Buffer size for getgrnam() and friends"
946 This sets the value of the buffer size for getgrnam() and friends.
947 By default, this is 256. (For reference, glibc uses 1024).
948 The value can be found using sysconf() with the _SC_GETGR_R_SIZE_MAX
951 comment "Support various families of functions"
953 config UCLIBC_LINUX_MODULE_26
954 bool "Linux kernel module functions (2.6)"
957 delete_module, init_module
958 are used in linux for loadable kernel modules.
960 Say N if you do not use kernel modules.
962 config UCLIBC_LINUX_SPECIFIC
963 bool "Linux specific functions"
966 accept4(), bdflush(),
967 capget(), capset(), eventfd(), fallocate(),
968 fstatfs(), getrandom(), inotify_*(), ioperm(), iopl(),
969 madvise(), modify_ldt(), pipe2(), personality(),
970 prctl()/arch_prctl(), pivot_root(), modify_ldt(),
971 ppoll(), readahead(), reboot(), remap_file_pages(),
972 sched_getaffinity(), sched_setaffinity(), sendfile(),
973 setfsgid(), setfsuid(), setresgid(), setresuid(),
974 splice(), vmsplice(), tee(), signalfd(), statfs(),
975 swapoff(), swapon(), sync_file_range(), syncfs(),
976 _sysctl(), sysinfo(), timerfd_*(), vhangup(), umount(),
979 config UCLIBC_HAS_GNU_ERROR
980 bool "Support GNU extensions for error-reporting"
983 Support for the GNU-specific error(), error_at_line(),
984 void (* error_print_progname)(), error_message_count
985 functions and variables. Some GNU packages
986 utilize these for extra useful output, but in general
989 If unsure, just answer N.
991 config UCLIBC_BSD_SPECIFIC
992 bool "BSD specific functions"
995 mincore(), getdomainname(), setdomainname()
999 config UCLIBC_HAS_BSD_ERR
1000 bool "BSD err functions"
1003 These functions are non-standard BSD extensions.
1004 err(), errx(), warn(), warnx(), verr(), verrx(), vwarn(), vwarnx()
1008 config UCLIBC_HAS_OBSOLETE_BSD_SIGNAL
1009 bool "BSD obsolete signal functions"
1011 These functions are provided as a compatibility interface for
1012 programs that make use of the historical System V signal API.
1013 This API is obsolete:
1014 new applications should use the POSIX signal API (sigaction(2),
1015 sigprocmask(2), etc.).
1018 sigset(), sighold(), sigrelse(), sigignore()
1022 config UCLIBC_HAS_OBSOLETE_SYSV_SIGNAL
1023 bool "SYSV obsolete signal functions"
1025 Use of sysv_signal() should be avoided; use sigaction(2) instead.
1029 config UCLIBC_NTP_LEGACY
1030 bool "ntp_*() aliases"
1032 Provide legacy aliases for ntp functions:
1033 ntp_adjtime(), ntp_gettime()
1035 It is safe to say N here.
1037 config UCLIBC_SV4_DEPRECATED
1038 bool "Enable SVr4 deprecated functions"
1040 These functions are DEPRECATED in System V release 4.
1041 Say N unless you desparately need one of the functions below:
1043 ustat() [use statfs(2) in your code instead]
1045 config UCLIBC_HAS_REALTIME
1046 bool "Realtime-related family of SUSv functions"
1049 These functions are part of the Timers option and need not
1050 be available on all implementations.
1051 Includes AIO, message-queue, scheduler, semaphore functions:
1066 clock_getres(), clock_gettime(), clock_settime()
1068 mlockall(), munlockall()
1080 sched_get_priority_max(), sched_get_priority_min()
1081 sched_getscheduler()
1082 sched_rr_get_interval()
1084 sched_setscheduler()
1091 sem_trywait(), sem_wait()
1094 sigtimedwait(), sigwaitinfo()
1097 timer_getoverrun(), timer_gettime(), timer_settime()
1099 config UCLIBC_HAS_ADVANCED_REALTIME
1100 bool "Advanced realtime-related family of SUSv functions"
1102 depends on UCLIBC_HAS_REALTIME
1104 These functions are part of the Timers option and need not
1105 be available on all implementations.
1107 clock_getcpuclockid()
1116 posix_spawnattr_destroy(), posix_spawnattr_init()
1117 posix_spawnattr_getflags(), posix_spawnattr_setflags()
1118 posix_spawnattr_getpgroup(), posix_spawnattr_setpgroup()
1119 posix_spawnattr_getschedparam(), posix_spawnattr_setschedparam()
1120 posix_spawnattr_getschedpolicy(), posix_spawnattr_setschedpolicy()
1121 posix_spawnattr_getsigdefault(), posix_spawnattr_setsigdefault()
1122 posix_spawnattr_getsigmask(), posix_spawnattr_setsigmask()
1123 posix_spawn_file_actions_addclose()
1124 posix_spawn_file_actions_adddup2()
1125 posix_spawn_file_actions_addopen()
1126 posix_spawn_file_actions_destroy()
1127 posix_spawn_file_actions_init()
1130 posix_typed_mem_get_info()
1131 pthread_mutex_timedlock()
1134 #config UCLIBC_HAS_TERMIOS
1135 # bool "termios functions"
1138 # Get and set terminal attributes, line control, get and set baud
1140 # termios(), tcgetattr(), tcsetattr(), tcsendbreak(), tcdrain(),
1141 # tcflush(), tcflow(), cfmakeraw(), cfgetospeed(), cfgetispeed(),
1142 # cfsetispeed(), cfsetospeed(), cfsetspeed()
1146 config UCLIBC_HAS_EPOLL
1150 epoll_create(), epoll_ctl(), epoll_wait() functions.
1152 config UCLIBC_HAS_XATTR
1153 bool "Extended Attributes"
1156 Extended Attributes support.
1171 Say N unless you need support for extended attributes and the
1172 filesystems do actually support them.
1174 config UCLIBC_HAS_PROFILING
1175 bool "Profiling support"
1178 gcc's -finstrument-functions needs these.
1180 Most people can safely answer N.
1182 config UCLIBC_HAS_CRYPT_IMPL
1183 bool "libcrypt support"
1186 libcrypt contains crypt(), setkey() and encrypt()
1188 config UCLIBC_HAS_SHA256_CRYPT_IMPL
1189 bool "libcrypt SHA256 support"
1190 depends on UCLIBC_HAS_CRYPT_IMPL
1192 This adds support for SHA256 password hashing via the crypt() function.
1193 Say N here if you do not need SHA256 crypt support.
1195 config UCLIBC_HAS_SHA512_CRYPT_IMPL
1196 bool "libcrypt SHA512 support"
1197 depends on UCLIBC_HAS_CRYPT_IMPL
1199 This adds support for SHA512 password hashing via the crypt() function.
1200 Say N here if you do not need SHA512 crypt support.
1202 config UCLIBC_HAS_CRYPT_STUB
1203 bool "libcrypt stubs"
1205 depends on !UCLIBC_HAS_CRYPT_IMPL
1207 Standards mandate that crypt(3) provides a stub if it is unavailable.
1208 If you enable this option then stubs for
1209 crypt(), setkey() and encrypt()
1210 will be provided in a small libcrypt.
1212 config UCLIBC_HAS_CRYPT
1214 depends on UCLIBC_HAS_CRYPT_IMPL || UCLIBC_HAS_CRYPT_STUB
1217 menuconfig UCLIBC_HAS_NETWORK_SUPPORT
1218 bool "Networking Support"
1221 Say N here if you do not need network support.
1223 if UCLIBC_HAS_NETWORK_SUPPORT
1224 config UCLIBC_HAS_SOCKET
1225 bool "Socket support"
1228 If you want to include support for sockets then answer Y.
1230 config UCLIBC_HAS_IPV4
1231 bool "IP version 4 support"
1233 select UCLIBC_HAS_SOCKET
1235 If you want to include support for the Internet Protocol
1236 (IP version 4) then answer Y.
1238 Most people will say Y.
1240 config UCLIBC_HAS_IPV6
1241 bool "IP version 6 support"
1242 select UCLIBC_HAS_SOCKET
1244 If you want to include support for the next version of the Internet
1245 Protocol (IP version 6) then answer Y.
1247 Most people should answer N.
1249 config UCLIBC_HAS_RPC
1250 bool "Remote Procedure Call (RPC) support"
1251 # RPC+socket-ipvX doesn't currently work.
1252 depends on UCLIBC_HAS_IPV4 || UCLIBC_HAS_IPV6
1254 If you want to include RPC support, enable this. RPC is rarely used
1255 for anything except for the NFS filesystem. Unless you plan to use
1256 NFS, you can probably leave this set to N and save some space.
1258 If you need to use NFS then you should answer Y.
1260 config UCLIBC_HAS_FULL_RPC
1261 bool "Full RPC support"
1262 depends on UCLIBC_HAS_RPC
1263 default y if !HAVE_SHARED
1265 Normally we enable just enough RPC support for things like rshd and
1266 nfs mounts to work. If you find you need the rest of the RPC stuff,
1267 then enable this option. Most people can safely answer N.
1269 config UCLIBC_HAS_REENTRANT_RPC
1270 bool "Reentrant RPC support"
1271 depends on UCLIBC_HAS_RPC
1272 default y if !HAVE_SHARED
1274 Most packages utilize the normal (non-reentrant) RPC functions, but
1275 some (like exportfs from nfs-utils) need these reentrant versions.
1277 Most people can safely answer N.
1279 config UCLIBC_USE_NETLINK
1280 bool "Use netlink to query interfaces"
1281 depends on UCLIBC_HAS_SOCKET
1283 In newer versions of Linux (2.4.17+), support was added for querying
1284 network device information via netlink rather than the old style
1285 ioctl's. Most of the time, the older ioctl style is sufficient (and
1286 it is smaller than netlink), but if you find that not all of your
1287 devices are being returned by the if_nameindex() function, you will
1288 have to use the netlink implementation.
1290 Most people can safely answer N.
1292 config UCLIBC_SUPPORT_AI_ADDRCONFIG
1293 bool "Support the AI_ADDRCONFIG flag"
1294 depends on UCLIBC_USE_NETLINK
1296 The implementation of AI_ADDRCONFIG is aligned with the glibc
1297 implementation using netlink to query interfaces to find both
1298 ipv4 and ipv6 support. This is only needed if an application uses
1299 the AI_ADDRCONFIG flag.
1301 Most people can safely answer N.
1303 config UCLIBC_HAS_BSD_RES_CLOSE
1304 bool "Support res_close() (bsd-compat)"
1306 Answer Y if you desperately want to support BSD compatibility in
1309 Most people will say N.
1311 config UCLIBC_HAS_COMPAT_RES_STATE
1312 bool "Use compatible but bloated _res"
1315 Answer Y if you build network utilities and they muck with resolver
1316 internals a lot (_res global structure). uclibc does not use most
1317 of _res.XXX fields, and with this option OFF they won't even exist.
1318 Which will make e.g. dig build fail.
1319 Answering N saves around 400 bytes in bss.
1321 config UCLIBC_HAS_EXTRA_COMPAT_RES_STATE
1322 bool "Use extra compatible but extra bloated _res"
1324 Answer Y if selecting UCLIBC_HAS_COMPAT_RES_STATE is not enough.
1325 As far as I can say, this should never be needed.
1327 config UCLIBC_HAS_RESOLVER_SUPPORT
1328 bool "DNS resolver functions"
1329 select UCLIBC_HAS_COMPAT_RES_STATE
1330 depends on UCLIBC_HAS_IPV4 || UCLIBC_HAS_IPV6
1332 Provide implementations for DNS resolver functions.
1333 In particular, the following functions will be added to the
1336 ns_skiprr, ns_initparse, ns_parserr, ns_msg_getflag,
1337 res_mkquery, res_init, res_ninit, res_close, res_nclose
1338 res_query, res_search, res_querydomain,
1340 ns_name_uncompress, ns_name_ntop, ns_name_pton, ns_name_unpack,
1341 ns_name_pack, ns_name_compress, ns_name_skip, dn_skipname,
1342 ns_get16, ns_get32, ns_put16, ns_put32
1347 menu "String and Stdio Support"
1349 config UCLIBC_HAS_STRING_GENERIC_OPT
1350 bool "Use faster (but larger) generic string functions"
1353 Answer Y to use the (tweaked) glibc generic string functions.
1355 In general, they are faster (but 3-5K larger) than the base
1356 uClibc string functions which are optimized solely for size.
1358 Many people will answer Y.
1360 config UCLIBC_HAS_STRING_ARCH_OPT
1361 bool "Use arch-specific assembly string functions (where available)"
1364 Answer Y to use any archtecture-specific assembly language string
1365 functions available for this target plaform.
1367 Note that assembly implementations are not available for all string
1368 functions, so some generic (written in C) string functions may
1371 These are small and fast, the only reason _not_ to say Y here is
1372 for debugging purposes.
1374 config UCLIBC_HAS_STDIO_FUTEXES
1375 bool "Use futexes for multithreaded I/O locking"
1376 depends on UCLIBC_HAS_THREADS_NATIVE
1378 If you want to compile uClibc to use futexes for low-level
1379 I/O locking, answer Y. Otherwise, answer N.
1381 config UCLIBC_HAS_CTYPE_TABLES
1382 bool "Use Table Versions Of 'ctype.h' Functions."
1385 Answer Y to use table versions of the 'ctype.h' functions.
1386 While the non-table versions are often smaller when building
1387 statically linked apps, they work only in stub locale mode.
1389 Most people will answer Y.
1391 config UCLIBC_HAS_CTYPE_SIGNED
1392 bool "Support Signed Characters In 'ctype.h' Functions."
1393 depends on UCLIBC_HAS_CTYPE_TABLES
1396 Answer Y to enable support for passing signed char values to
1397 the 'ctype.h' functions. ANSI/ISO C99 and SUSv3 specify that
1398 these functions are only defined for unsigned char values and
1399 EOF. However, glibc allows negative signed char values as well
1400 in order to support 'broken old programs'.
1402 Most people will answer Y.
1405 prompt "ctype argument checking"
1406 depends on UCLIBC_HAS_CTYPE_TABLES
1407 default UCLIBC_HAS_CTYPE_UNSAFE
1409 Please select the invalid arg behavior you want for the 'ctype'
1412 The 'ctype' functions are now implemented using table lookups, with
1413 the arg being the index. This can result in incorrect memory accesses
1414 or even segfaults for args outside of the allowed range.
1416 NOTE: This only affects the 'ctype' _functions_. It does not affect
1417 the macro implementations.
1419 config UCLIBC_HAS_CTYPE_UNSAFE
1420 bool "Do not check -- unsafe"
1422 config UCLIBC_HAS_CTYPE_CHECKED
1423 bool "Detect and handle appropriately"
1425 config UCLIBC_HAS_CTYPE_ENFORCED
1426 bool "Issue a diagnostic and abort()"
1431 config UCLIBC_HAS_WCHAR
1432 bool "Wide Character Support"
1434 Answer Y to enable wide character support. This will make uClibc
1435 much larger. It is also currently required for locale support.
1437 Most people will answer N.
1439 config UCLIBC_HAS_LIBICONV
1440 bool "Iconv Support"
1442 Add tiny iconv support for charset conversion from and to UTF-8.
1444 config UCLIBC_HAS_LIBINTL
1445 bool "Intl stubs support"
1447 If you enable this option you get stubs for the gettext family of
1450 config UCLIBC_HAS_LOCALE
1451 bool "Locale Support"
1452 select UCLIBC_HAS_WCHAR
1453 select UCLIBC_HAS_CTYPE_TABLES
1455 uClibc now has full ANSI/ISO C99 locale support (except for
1456 wcsftime() and collating items in regex). Be aware that enabling
1457 this option will make uClibc much larger.
1459 Enabling UCLIBC_HAS_LOCALE with the default set of supported locales
1460 (169 UTF-8 locales, and 144 locales for other codesets) will enlarge
1461 uClibc by around 300k. You can reduce this size by building your own
1462 custom set of locate data (see extra/locale/LOCALES for details).
1464 uClibc's locale support is still under development. For example,
1465 codesets using shift states are not currently supported. Support is
1466 planned in the next iteration of locale support.
1468 Answer Y to enable locale support. Most people will answer N.
1472 prompt "Locale data"
1473 depends on UCLIBC_HAS_LOCALE
1474 default UCLIBC_BUILD_MINIMAL_LOCALE
1476 config UCLIBC_BUILD_MINIMAL_LOCALE
1477 bool "Only selected locales"
1478 depends on UCLIBC_HAS_LOCALE
1480 If you do not need all locales that are available on your
1481 host-box, then set this to 'Y'.
1483 config UCLIBC_BUILD_ALL_LOCALE
1485 depends on UCLIBC_HAS_LOCALE
1487 This builds all the locales that are available on your
1492 config UCLIBC_BUILD_MINIMAL_LOCALES
1493 string "locales to use"
1494 depends on UCLIBC_BUILD_MINIMAL_LOCALE
1497 Space separated list of locales to use.
1504 config UCLIBC_HAS_XLOCALE
1505 bool "Extended Locale Support (experimental/incomplete)"
1506 depends on UCLIBC_HAS_LOCALE
1508 Answer Y to enable extended locale support similar to that provided
1509 by glibc. This is primarily intended to support libstd++
1511 However, it also allows thread-specific locale selection via
1514 Most people will answer N.
1516 config UCLIBC_HAS_HEXADECIMAL_FLOATS
1517 bool "Support hexadecimal float notation"
1518 depends on UCLIBC_HAS_CTYPE_TABLES
1519 depends on UCLIBC_HAS_FLOATS
1521 Answer Y to enable support for hexadecimal float notation in the
1522 (wchar and) char string to floating point conversion functions, as
1523 well as support for the %a and %A conversion specifiers in the
1524 *printf() and *scanf() functions.
1526 Most people will answer N.
1528 config UCLIBC_HAS_GLIBC_DIGIT_GROUPING
1529 bool "Support glibc's \"'\" flag for allowing locale-specific digit grouping"
1530 depends on UCLIBC_HAS_LOCALE
1531 depends on UCLIBC_HAS_FLOATS
1533 Answer Y to enable support for glibc's \"'\" flag for allowing
1534 locale-specific digit grouping in base 10 integer conversions and
1535 appropriate floating point conversions in the *printf() and *scanf()
1538 Most people will answer N.
1540 config UCLIBC_HAS_SCANF_LENIENT_DIGIT_GROUPING
1541 bool "Do not require digit grouping when the \"'\" flag is specified"
1542 depends on UCLIBC_HAS_GLIBC_DIGIT_GROUPING
1545 Answer Y to make digit grouping optional when the \"'\" flag is
1547 This is the standard glibc behavior. If the initial string of digits
1548 exceeds the maximum group number, the input will be treated as a
1549 normal non-grouped number.
1551 Most people will answer N.
1553 config UCLIBC_HAS_GLIBC_CUSTOM_PRINTF
1554 bool "Support glibc's register_printf_function() (glibc-compat)"
1555 depends on !USE_OLD_VFPRINTF
1557 Answer Y to support glibc's register_printf_function() to allow an
1558 application to add its own printf conversion specifiers.
1559 parse_printf_format() is also enabled.
1561 NOTE: Limits the number or registered specifiers to 10.
1562 NOTE: Requires new conversion specifiers to be ASCII
1563 characters (0-0x7f). This is to avoid problems with processing
1564 format strings in locales with different multibyte conversions.
1566 Most people will answer N.
1568 config USE_OLD_VFPRINTF
1569 bool "Use the old vfprintf implementation"
1570 depends on !UCLIBC_HAS_WCHAR
1572 Set to true to use the old vfprintf instead of the new. This is
1573 roughly C89 compliant with some extensions, and is much smaller.
1574 However, it does not support wide chars, positional args, or glibc
1575 custom printf specifiers.
1577 Most people will answer N.
1579 config UCLIBC_PRINTF_SCANF_POSITIONAL_ARGS
1580 int "Maximum number of positional args. Either 0 or >= 9."
1581 depends on !USE_OLD_VFPRINTF
1584 Set the maximum number of positional args supported by the
1585 printf/scanf functions. The Single Unix Specification Version 3
1586 requires a minimum value of 9. Setting this to a value lower than
1587 9 will disable positional arg support and cause the NL_ARGMAX macro
1588 in limits.h to be #undef'd.
1590 WARNING! The workspace to support positional args is currently
1591 allocated on the stack. You probably don't want to set
1592 this to too high a value.
1594 Most people will answer 9.
1597 prompt "Stdio buffer size"
1598 default UCLIBC_HAS_STDIO_BUFSIZ_4096
1600 Please select a value for BUFSIZ. This will be used by the
1601 stdio subsystem as the default buffer size for a file, and
1602 affects fopen(), setvbuf(), etc.
1604 NOTE: Setting this to 'none' will disable buffering completely.
1605 However, BUFSIZ will still be defined in stdio.h as 256 because
1606 many applications use this value.
1608 config UCLIBC_HAS_STDIO_BUFSIZ_NONE
1609 bool "none (WARNING - BUFSIZ will be 256 in stdio.h)"
1610 depends on !UCLIBC_HAS_WCHAR
1612 config UCLIBC_HAS_STDIO_BUFSIZ_256
1613 bool "256 (minimum ANSI/ISO C99 value)"
1615 config UCLIBC_HAS_STDIO_BUFSIZ_512
1618 config UCLIBC_HAS_STDIO_BUFSIZ_1024
1621 config UCLIBC_HAS_STDIO_BUFSIZ_2048
1624 config UCLIBC_HAS_STDIO_BUFSIZ_4096
1627 config UCLIBC_HAS_STDIO_BUFSIZ_8192
1630 # If you add more choices, you will need to update uClibc_stdio.h.
1635 prompt "Stdio builtin buffer size (uClibc-specific)"
1636 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1637 default UCLIBC_HAS_STDIO_BUILTIN_BUFFER_NONE
1639 When a FILE is created with fopen(), an attempt is made to allocate
1640 a BUFSIZ buffer for it. If the allocation fails, fopen() will still
1641 succeed but the FILE will be unbuffered.
1643 This option adds a small amount of space to each FILE to act as an
1644 emergency buffer in the event of a buffer allocation failure.
1646 Most people will answer None.
1648 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_NONE
1651 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_4
1654 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_8
1657 # If you add more choices, you will need to update uClibc_stdio.h.
1661 config UCLIBC_HAS_STDIO_SHUTDOWN_ON_ABORT
1662 bool "Attempt to shutdown stdio subsystem when abort() is called."
1664 ANSI/ISO C99 requires abort() to be asyn-signal-safe. So there was
1665 a behavioral change made in SUSv3. Previously, abort() was required
1666 to have the affect of fclose() on all open streams. The wording has
1667 been changed to "may" from "shall".
1669 Most people will answer N.
1671 config UCLIBC_HAS_STDIO_GETC_MACRO
1672 bool "Provide a macro version of getc()"
1673 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1676 Provide a macro version of getc().
1678 Most people will answer Y.
1680 config UCLIBC_HAS_STDIO_PUTC_MACRO
1681 bool "Provide a macro version of putc()"
1682 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1685 Provide a macro version of putc().
1687 Most people will answer Y.
1689 config UCLIBC_HAS_STDIO_AUTO_RW_TRANSITION
1690 bool "Support auto-r/w transition"
1693 Answer Y to enable the stdio subsystem to automaticly transition
1694 between reading and writing. This relaxes the ANSI/ISO C99
1697 When a file is opened with update mode ('+' as the second or third
1698 character in the list of mode argument values), both input and output
1699 may be performed on the associated stream. However, output shall not
1700 be directly followed by input without an intervening call to the
1701 fflush function or to a file positioning function (fseek, fsetpos,
1702 or rewind), and input shall not be directly followed by output without
1703 an intervening call to a file positioning function, unless the input
1704 operation encounters endÂofÂfile.
1706 Most people will answer Y.
1708 config UCLIBC_HAS_FOPEN_LARGEFILE_MODE
1709 bool "Support an fopen() 'F' flag for large file mode (uClibc-specific)"
1711 Answer Y to enable a uClibc-specific extension to allow passing an
1712 additional 'F' flag in the mode string for fopen() to specify that
1713 the file should be open()ed with the O_LARGEFILE flag set.
1715 Most people will answer N.
1717 config UCLIBC_HAS_FOPEN_EXCLUSIVE_MODE
1718 bool "Support an fopen() 'x' flag for exclusive mode (glibc-compat)"
1720 Answer Y to support a glibc extension to allow passing
1721 additional 'x' flag in the mode string for fopen() to specify that
1722 the file should be open()ed with the O_EXCL flag set.
1724 Most people will answer N.
1726 config UCLIBC_HAS_FOPEN_CLOSEEXEC_MODE
1727 bool "Support an fopen() 'e' flag for close-on-exec mode (glibc-compat)"
1729 Answer Y to support a glibc extension to allow passing
1730 additional 'e' flag in the mode string for fopen() to specify that
1731 the file should be open()ed with the O_CLOEXEC flag set.
1733 Most people will answer N.
1735 config UCLIBC_HAS_GLIBC_CUSTOM_STREAMS
1736 bool "Support fmemopen(), open_memstream(), and fopencookie() (glibc-compat)"
1738 Answer Y to support the glibc 'custom stream' extension functions
1739 fmemopen(), open_memstream(), and fopencookie().
1741 NOTE: There are some minor differences regarding seeking behavior.
1743 Most people will answer N.
1745 config UCLIBC_HAS_PRINTF_M_SPEC
1746 bool "Support the '%m' specifier in printf format strings (glibc-compat)"
1748 Answer Y to support a glibc extension to interpret '%m' in printf
1749 format strings as an instruction to output the error message string
1750 (as generated by strerror) corresponding to the current value of
1753 Most people will answer N.
1755 config UCLIBC_HAS_ERRNO_MESSAGES
1756 bool "Include the errno message text in the library"
1759 Answer Y if you want to include the errno message text in the
1760 library. This adds about 3K to the library, but enables strerror()
1761 to generate text other than 'Unknown error <number>'.
1763 Most people will answer Y.
1765 config UCLIBC_HAS_SYS_ERRLIST
1766 bool "Support sys_errlist[] (obsolete-compat)"
1767 depends on UCLIBC_HAS_ERRNO_MESSAGES
1769 Answer Y if you want to support the obsolete sys_errlist[].
1770 This adds about 0.5k to the library, except for the mips
1771 arch where it adds over 4K.
1773 WARNING! In the future, support for sys_errlist[] may be unavailable
1774 in at least some configurations. In fact, it may be removed
1777 Most people will answer N.
1779 Application writers: use the strerror(3) function.
1781 config UCLIBC_HAS_SIGNUM_MESSAGES
1782 bool "Include the signum message text in the library"
1785 Answer Y if you want to include the signum message text in the
1786 library. This adds about 0.5K to the library, but enables strsignal()
1787 to generate text other than 'Unknown signal <number>'.
1789 Most people will answer Y.
1791 config UCLIBC_HAS_SYS_SIGLIST
1792 bool "Support sys_siglist[] (bsd-compat)"
1793 depends on UCLIBC_HAS_SIGNUM_MESSAGES
1795 Answer Y if you want to support sys_siglist[].
1797 WARNING! In the future, support for sys_siglist[] may be unavailable
1798 in at least some configurations. In fact, it may be removed
1801 Most people will answer N.
1803 config UCLIBC_HAS_GNU_GETOPT
1804 bool "Support gnu getopt"
1807 Answer Y if you want to include full gnu getopt() instead of a
1808 (much smaller) SUSv3 compatible getopt().
1809 Note that getopt_long, getopt_long_only as well as getsubopt
1810 are implemented on top of this choice.
1812 Most people will answer Y.
1814 config UCLIBC_HAS_GETOPT_LONG
1815 bool "Support getopt_long/getopt_long_only (glibc-compat)"
1818 Answer Y if you want to include getopt_long[_only()] used by many
1821 Most people will answer Y.
1823 config UCLIBC_HAS_GNU_GETSUBOPT
1824 bool "Support getsubopt"
1827 Answer Y if you want to include getsubopt().
1829 Most people will answer Y.
1831 config UCLIBC_HAS_ARGP
1832 bool "Support argp (as standalone shared object)"
1833 select UCLIBC_HAS_GETOPT_LONG
1834 select UCLIBC_HAS_GNU_GETOPT
1837 Argp is an interface for parsing unix-style argument vectors. Unlike
1838 the common getopt interface, it provides many advanced features in
1839 addition to parsing options, such as automatic output in response to
1840 `--help' and `--version' options.
1841 A library can export an argp option parser, which programs can easily
1842 use in conjunction with their own option parser.
1843 Argp support is needed by elfutils libdw.
1845 Most people can safely answer N.
1852 config UCLIBC_HAS_REGEX
1853 bool "Regular Expression Support"
1856 POSIX regular expression code is really big -- 53k all by itself.
1857 If you don't use regular expressions, turn this off and save space.
1858 Of course, if you only statically link, leave this on, since it will
1859 only be included in your apps if you use regular expressions.
1861 config UCLIBC_HAS_REGEX_OLD
1862 bool "Use the older (stable) regular expression code"
1863 depends on UCLIBC_HAS_REGEX
1866 There are two versions of regex. The older (stable) version has
1867 been in uClibc for quite a long time but hasn't seen too many
1868 updates. It also has some known issues when dealing with uncommon
1869 corner cases and multibyte/unicode strings. However, it is quite
1870 a bit smaller than the newer version.
1872 If the older version has worked for you and you don't need unicode
1873 support, then stick with the old version (and say Y here).
1874 Otherwise, you should use the new version (and say N here).
1876 config UCLIBC_HAS_FNMATCH
1877 bool "fnmatch Support"
1882 config UCLIBC_HAS_FNMATCH_OLD
1883 bool "Use the older (stable) fnmatch code"
1884 depends on UCLIBC_HAS_FNMATCH
1887 There are two versions of fnmatch. The older (stable) version has
1888 been in uClibc for quite a long time but hasn't seen too many
1889 updates. It also has some known issues when dealing with uncommon
1890 corner cases and multibyte/unicode strings. However, it is quite
1891 a bit smaller than the newer version.
1893 If the older version has worked for you and you don't need unicode
1894 support, then stick with the old version (and say Y here).
1895 Otherwise, you should use the new version (and say N here).
1897 config UCLIBC_HAS_WORDEXP
1898 bool "Support the wordexp() interface"
1899 depends on UCLIBC_HAS_GLOB
1901 The SuSv3 wordexp() interface performs word expansions per the Shell
1902 and Utilities volume of IEEE Std 1003.1-2001, Section 2.6. It is
1903 intended for use by applications that want to implement all of the
1904 standard Bourne shell expansions on input data.
1906 This interface is rarely used, and very large. Unless you have a
1907 pressing need for wordexp(), you should probably answer N.
1909 config UCLIBC_HAS_NFTW
1910 bool "Support the nftw() interface"
1912 The SuSv3 nftw() interface is used to recursively descend
1913 directory paths while repeatedly calling a function.
1915 This interface is rarely used, and adds around 4.5k. Unless you have
1916 a pressing need for nftw(), you should probably answer N.
1918 config UCLIBC_HAS_FTW
1919 bool "Support the ftw() interface (SUSv4-obsolete)"
1920 depends on UCLIBC_SUSV4_LEGACY
1922 The SuSv3 ftw() interface is used to recursively descend
1923 directory paths while repeatedly calling a function.
1925 This interface is rarely used, and adds around 4.5k. Unless you have
1926 a pressing need for ftw(), you should probably answer N.
1928 config UCLIBC_HAS_FTS
1929 bool "Support the fts() interface (bsd-compat)"
1931 The fts functions are provided for traversing UNIX file hierarchies.
1933 This interface is currently used by the elfutils and adds
1935 You should port your application to use the POSIX nftw()
1938 Unless you need to build/use elfutils, you should prolly answer N.
1940 config UCLIBC_HAS_GLOB
1941 bool "Support the glob() interface"
1942 depends on UCLIBC_HAS_FNMATCH
1946 The glob interface is somewhat large (weighing in at about 2,5k). It
1947 is used fairly often, but is an option since people wanting to go for
1948 absolute minimum size may wish to omit it.
1950 Most people will answer Y.
1952 config UCLIBC_HAS_GNU_GLOB
1953 bool "Support gnu glob() interface"
1954 depends on UCLIBC_HAS_GLOB
1956 The gnu glob interface is somewhat larger (weighing in at about 4,2k)
1957 than it's SuSv3 counterpart (and is out of date). It is an old copy
1958 from glibc and does not support all the GNU specific options.
1960 Answer Y if you want to include full gnu glob() instead of the smaller
1961 SUSv3 compatible glob().
1963 Most people will answer N.
1970 menu "Library Installation Options"
1972 config RUNTIME_PREFIX
1973 string "uClibc runtime library directory"
1974 default "/usr/$(TARGET_ARCH)-linux-uclibc/"
1976 RUNTIME_PREFIX is the directory into which the uClibc runtime
1977 libraries will be installed. The result will look something
1980 lib/ <contains all runtime libraries>
1981 usr/bin/ldd <the ldd utility program>
1982 sbin/ldconfig <the ldconfig utility program>
1983 This value is used by the 'make install' Makefile target. Since this
1984 directory is compiled into the shared library loader, you will need to
1985 recompile uClibc if you change this value...
1987 For a typical target system this should be set to "/", such that
1988 'make install' will install /lib/libuClibc-<VERSION>.so
1991 string "uClibc development environment directory"
1992 default "/usr/$(TARGET_ARCH)-linux-uclibc/usr/"
1994 DEVEL_PREFIX is the directory into which the uClibc development
1995 environment will be installed. The result will look something
1998 lib/ <contains static libs>
1999 include/ <Where all the header files go>
2000 This value is used by the 'make install' Makefile target when
2001 installing a uClibc development environment.
2003 For a typical target system this should be set to "/usr", such that
2004 'make install' will install /usr/include/<header files>.
2007 string "library path component"
2010 Path component where libraries reside.
2012 For a typical target system this should be set to "lib", such that
2013 'make install' will install libraries to "/lib" and "/usr/lib"
2015 DEVEL_PREFIX/MULTILIB_DIR
2016 RUNTIME_PREFIX/MULTILIB_DIR
2018 Other settings may include "lib32" or "lib64".
2020 config HARDWIRED_ABSPATH
2021 bool "Hardwire absolute paths into linker scripts"
2024 This prepends absolute paths to the libraries mentioned in linker
2025 scripts such as libc.so.
2027 This is a build time optimization. It has no impact on dynamic
2028 linking at runtime, which doesn't use linker scripts.
2030 You must disable this to use uClibc with old non-sysroot toolchains,
2031 such as the prebuilt binary cross compilers at:
2032 http://uclibc.org/downloads/binaries
2034 The amount of time saved by this optimization is actually too small to
2035 measure. The linker just had to search the library path to find the
2036 linker script, so the dentries are cache hot if it has to search the
2037 same path again. But it's what glibc does, so we do it too.
2042 menu "Security options"
2044 config UCLIBC_BUILD_PIE
2045 bool "Build utilities as ET_DYN/PIE executables"
2046 depends on HAVE_SHARED
2047 depends on TARGET_arm || TARGET_frv || TARGET_i386 || TARGET_mips || TARGET_powerpc || TARGET_nds32
2048 select FORCE_SHAREABLE_TEXT_SEGMENTS
2050 If you answer Y here, ldd and iconv are built as ET_DYN/PIE
2053 It requires gcc-3.4 and binutils-2.15 (for arm 2.16) or later.
2054 More about ET_DYN/PIE binaries on <http://pax.grsecurity.net/> .
2056 WARNING: This option also enables FORCE_SHAREABLE_TEXT_SEGMENTS, so
2057 all libraries have to be built with -fPIC or -fpic, and all
2058 assembler functions must be written as position independent
2061 config UCLIBC_HAS_ARC4RANDOM
2062 bool "Include the arc4random() function"
2064 Answer Y to support the OpenBSD-like arc4random() function. This
2065 function picks a random number between 0 and N, and will always return
2066 something even if the random driver is dead. If urandom fails then
2067 gettimeofday(2) will be used as the random seed. This function is
2068 designed to be more dependable than invoking /dev/urandom directly.
2069 OpenSSL and OpenNTPD currently support this function.
2071 Most people will answer N.
2073 config ARC4RANDOM_USES_NODEV
2074 bool "Do not use /dev/urandom with arc4random()"
2075 depends on UCLIBC_HAS_ARC4RANDOM
2077 Answer Y to use gettimeofday(2) and getpid(2) exclusively for
2078 arc4random(). This is not a bad idea for a diskless system, but
2079 it uses a lot of syscalls to stir each array element.
2081 Most people will answer N.
2086 config UCLIBC_HAS_SSP
2087 bool "Support for GCC stack smashing protector"
2088 depends on !HAVE_NO_SSP
2090 Add code to support GCC's -fstack-protector[-all] option to uClibc.
2091 This requires GCC 4.1 or newer. GCC does not have to provide libssp,
2092 the needed functions are added to ldso/libc instead.
2094 GCC's stack protector is a reimplementation of IBM's propolice.
2095 See http://www.trl.ibm.com/projects/security/ssp/ and
2096 http://www.linuxfromscratch.org/hints/downloads/files/ssp.txt
2099 Note that NOEXECSTACK on a kernel with address space randomization
2100 is generally sufficient to prevent most buffer overflow exploits
2101 without increasing code size. This option essentially adds debugging
2104 Most people will answer N.
2106 config SSP_QUICK_CANARY
2107 bool "Use simple guard values without accessing /dev/urandom"
2108 depends on UCLIBC_HAS_SSP
2110 Use gettimeofday(2) to define the __guard without accessing
2112 WARNING: This makes smashing stack protector vulnerable to timing
2114 Most people will answer N.
2117 prompt "Propolice protection blocking signal"
2118 depends on UCLIBC_HAS_SSP
2120 default PROPOLICE_BLOCK_SEGV
2122 "abort" use SIGABRT to block offending programs.
2123 This is the default implementation.
2125 "segfault" use SIGSEGV to block offending programs.
2126 Use this for debugging.
2128 If unsure, answer "abort".
2130 config PROPOLICE_BLOCK_ABRT
2133 config PROPOLICE_BLOCK_SEGV
2138 config UCLIBC_BUILD_SSP
2139 bool "Build uClibc with -fstack-protector"
2140 depends on UCLIBC_HAS_SSP
2142 Build all uClibc libraries and executables with -fstack-protector,
2143 adding extra stack overflow checking to most uClibc functions.
2145 config UCLIBC_BUILD_RELRO
2146 bool "Build uClibc with linker option -z RELRO"
2147 depends on HAVE_SHARED
2150 Build all libraries and executables with "ld -z relro".
2152 This tells the linker to mark chunks of an executable or shared
2153 library read-only after applying dynamic relocations. (This comes
2154 up when a global const variable is initialized to the address of a
2155 function or the value of another global variable.)
2157 This is a fairly obscure option the ld man page doesn't even bother
2158 to document properly. It's a security paranoia issue that's more
2159 likely to consume memory (by allocating an extra page) rather than
2162 This is explained in more depth at
2163 http://www.airs.com/blog/archives/189
2165 Nobody is likely to care whether you say Y or N here.
2167 config UCLIBC_BUILD_NOW
2168 bool "Build uClibc with linker option -z NOW"
2169 depends on HAVE_SHARED
2171 Build all libraries and executables with "ld -z now".
2173 This tells the linker to resolve all symbols when the library is
2174 first loaded, rather than when each function is first called. This
2175 increases start-up latency by a few microseconds and may do
2176 unnecessary work (resolving symbols that are never used), but the
2177 realtime people like it for making microbenchmark timings slightly
2178 more predictable and in some cases it can be slightly faster due to
2179 CPU cache behavior (not having to fault the linker back in to do
2180 lazy symbol resolution).
2182 Most people can't tell the difference between selecting Y or N here.
2184 config UCLIBC_BUILD_NOEXECSTACK
2185 bool "Build uClibc with noexecstack marking"
2188 Mark all assembler files as noexecstack, which will mark uClibc
2189 as not requiring an executable stack. (This doesn't prevent other
2190 files you link against from claiming to need an executable stack, it
2191 just won't cause uClibc to request it unnecessarily.)
2193 This is a security thing to make buffer overflows harder to exploit.
2194 By itself, it's kind of useless, as Linus Torvalds explained in 1998:
2195 http://old.lwn.net/1998/0806/a/linus-noexec.html
2197 It only actually provides any security when combined with address
2198 space randomization, explained here: http://lwn.net/Articles/121845/
2200 Address space randomization is on by default in current linux
2201 kernels (although it can be disabled using the option
2204 You should probably say Y.
2208 menu "Development/debugging options"
2210 config CROSS_COMPILER_PREFIX
2211 string "Cross-compiling toolchain prefix"
2214 The prefix used to execute your cross-compiling toolchain. For
2215 example, if you run 'arm-linux-uclibc-gcc' to compile something,
2216 then enter 'arm-linux-uclibc-' here.
2218 config UCLIBC_EXTRA_CFLAGS
2219 string "Extra CFLAGS"
2222 Add any additional CFLAGS to be used to build uClibc.
2225 bool "Enable debugging symbols"
2226 select EXTRA_WARNINGS
2228 Say Y here if you wish to compile uClibc with debugging symbols.
2229 This will allow you to use a debugger to examine uClibc internals
2230 while applications are running. This increases the size of the
2231 library considerably and should only be used when doing development.
2232 If you are doing development and want to debug uClibc, answer Y.
2234 Otherwise, answer N.
2237 bool "Build pthread with debugging output"
2238 depends on UCLIBC_HAS_THREADS && UCLIBC_HAS_LINUXTHREADS
2240 Enable debug output in libpthread. This is only useful when doing
2241 development in libpthread itself.
2243 Otherwise, answer N.
2246 bool "Strip libraries and executables"
2250 Say Y here if you do wish to strip all uClibc libraries and
2251 executables. No stripping increases the size of the binaries
2252 considerably, but makes it possible to debug uClibc libraries.
2253 Most people will answer Y.
2256 bool "Build with run-time assertion testing"
2258 Say Y here to include runtime assertion tests.
2259 This enables runtime assertion testing in some code, which can
2260 increase the size of the library and incur runtime overhead.
2261 If you say N, then this testing will be disabled.
2263 config SUPPORT_LD_DEBUG
2264 bool "Build the shared library loader with debugging support"
2265 depends on HAVE_SHARED
2267 Answer Y here to enable all the extra code needed to debug the uClibc
2268 native shared library loader. The level of debugging noise that is
2269 generated depends on the LD_DEBUG environment variable... Just set
2270 LD_DEBUG to something like: 'LD_DEBUG=token1,token2,.. prog' to
2271 debug your application. Diagnostic messages will then be printed to
2274 For now these debugging tokens are available:
2275 detail provide more information for some options
2276 move display copy processing
2277 symbols display symbol table processing
2278 reloc display relocation processing; detail shows the
2280 nofixups never fixes up jump relocations
2281 bindings displays the resolve processing (function calls);
2282 detail shows the relocation patch
2283 all Enable everything!
2285 The additional environment variable:
2286 LD_DEBUG_OUTPUT=file
2287 redirects the diagnostics to an output file created using
2288 the specified name and the process id as a suffix.
2290 An excellent start is simply:
2291 $ LD_DEBUG=binding,move,symbols,reloc,detail ./appname
2292 or to log everything to a file named 'logfile', try this
2293 $ LD_DEBUG=all LD_DEBUG_OUTPUT=logfile ./appname
2295 If you are doing development and want to debug uClibc's shared library
2296 loader, answer Y. Mere mortals answer N.
2298 config SUPPORT_LD_DEBUG_EARLY
2299 bool "Build the shared library loader with early debugging support"
2300 depends on HAVE_SHARED
2302 Answer Y here to if you find the uClibc shared library loader is
2303 crashing or otherwise not working very early on. This is typical
2304 only when starting a new port when you haven't figured out how to
2305 properly get the values for argc, argv, environ, etc. This method
2306 allows a degree of visibility into the very early shared library
2307 loader initialization process. If you are doing development and want
2308 to debug the uClibc shared library loader early initialization,
2309 answer Y. Mere mortals answer N.
2311 config UCLIBC_MALLOC_DEBUGGING
2312 bool "Build malloc with debugging support"
2313 depends on MALLOC || MALLOC_STANDARD
2316 Answer Y here to compile extra debugging support code into malloc.
2317 Malloc debugging output may then be enabled at runtime using the
2318 MALLOC_DEBUG environment variable.
2320 The value of MALLOC_DEBUG should be an integer, which is interpreted
2321 as a bitmask with the following bits:
2322 1 - do extra consistency checking
2323 2 - output messages for malloc/free calls and OS
2325 4 - output messages for the `MMB' layer
2326 8 - output messages for internal malloc heap manipulation
2329 Because this increases the size of malloc appreciably (due to strings
2330 etc), you should say N unless you need to debug a malloc problem.
2332 config UCLIBC_HAS_BACKTRACE
2333 bool "Add support for application self-debugging"
2334 depends on HAVE_SHARED
2336 Answer Y here to compile support for application self-debugging that
2337 provides the following new functions:
2338 backtrace, backtrace_symbols, backtrace_symbols_fd
2340 The backtrace functionality is currently supported on some platforms, and it
2341 based on dwarf2 informations to properly work, so any application that
2342 want to use backtrace needs to be built with -fexceptions flag.
2344 The symbol names may be unavailable without the use of special linker
2345 options. For systems using the GNU linker, it is necessary to use the
2346 -rdynamic linker option too. Note that names of "static" functions are not
2347 exposed, and won't be available in the backtrace.
2350 string "Compiler Warnings"
2353 Set this to the set of compiler warnings you wish to see while compiling.
2355 config EXTRA_WARNINGS
2356 bool "Enable extra annoying warnings"
2358 If you wish to build with extra warnings enabled, say Y here.