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_aarch64 if DESIRED_TARGET_ARCH = "aarch64"
19 default TARGET_alpha if DESIRED_TARGET_ARCH = "alpha"
20 default TARGET_arc if DESIRED_TARGET_ARCH = "arc"
21 default TARGET_arm if DESIRED_TARGET_ARCH = "arm"
22 default TARGET_avr32 if DESIRED_TARGET_ARCH = "avr32"
23 default TARGET_bfin if DESIRED_TARGET_ARCH = "bfin"
24 default TARGET_cris if DESIRED_TARGET_ARCH = "cris"
25 default TARGET_csky if DESIRED_TARGET_ARCH = "csky"
26 default TARGET_frv if DESIRED_TARGET_ARCH = "frv"
27 default TARGET_h8300 if DESIRED_TARGET_ARCH = "h8300"
28 default TARGET_hppa if DESIRED_TARGET_ARCH = "hppa"
29 default TARGET_i386 if DESIRED_TARGET_ARCH = "i386"
30 default TARGET_ia64 if DESIRED_TARGET_ARCH = "ia64"
31 default TARGET_lm32 if DESIRED_TARGET_ARCH = "lm32"
32 default TARGET_m68k if DESIRED_TARGET_ARCH = "m68k"
33 default TARGET_metag if DESIRED_TARGET_ARCH = "metag"
34 default TARGET_microblaze if DESIRED_TARGET_ARCH = "microblaze"
35 default TARGET_mips if DESIRED_TARGET_ARCH = "mips"
36 default TARGET_nds32 if DESIRED_TARGET_ARCH = "nds32"
37 default TARGET_nios2 if DESIRED_TARGET_ARCH = "nios2"
38 default TARGET_or1k if DESIRED_TARGET_ARCH = "or1k"
39 default TARGET_powerpc if DESIRED_TARGET_ARCH = "powerpc"
40 default TARGET_sh if DESIRED_TARGET_ARCH = "sh"
41 default TARGET_sparc if DESIRED_TARGET_ARCH = "sparc"
42 default TARGET_sparc64 if DESIRED_TARGET_ARCH = "sparc64"
43 default TARGET_tile if DESIRED_TARGET_ARCH = "tile"
44 default TARGET_x86_64 if DESIRED_TARGET_ARCH = "x86_64"
45 default TARGET_xtensa if DESIRED_TARGET_ARCH = "xtensa"
47 The architecture of your target.
67 # someone could sync this tree:
68 # http://linux-c6x.org/git/?p=uClibc.git;a=summary
102 config TARGET_microblaze
117 config TARGET_powerpc
126 config TARGET_sparc64
141 menu "Target Architecture Features and Options"
144 source "extra/Configs/Config.aarch64"
148 source "extra/Configs/Config.alpha"
152 source "extra/Configs/Config.arm"
156 source "extra/Configs/Config.avr32"
160 source "extra/Configs/Config.bfin"
164 source "extra/Configs/Config.cris"
168 source "extra/Configs/Config.csky"
172 source "extra/Configs/Config.frv"
176 source "extra/Configs/Config.h8300"
180 source "extra/Configs/Config.hppa"
184 source "extra/Configs/Config.i386"
188 source "extra/Configs/Config.ia64"
192 source "extra/Configs/Config.lm32"
196 source "extra/Configs/Config.m68k"
200 source "extra/Configs/Config.metag"
204 source "extra/Configs/Config.nds32"
208 source "extra/Configs/Config.nios2"
212 source "extra/Configs/Config.microblaze"
216 source "extra/Configs/Config.mips"
220 source "extra/Configs/Config.or1k"
224 source "extra/Configs/Config.powerpc"
228 source "extra/Configs/Config.sh"
232 source "extra/Configs/Config.sparc"
236 source "extra/Configs/Config.sparc64"
240 source "extra/Configs/Config.tile"
244 source "extra/Configs/Config.x86_64"
248 source "extra/Configs/Config.xtensa"
252 source "extra/Configs/Config.c6x"
256 source "extra/Configs/Config.arc"
259 config TARGET_SUBARCH
261 default "e500" if CONFIG_E500
262 default "classic" if CONFIG_CLASSIC
263 default "sh4" if CONFIG_SH4
264 default "sh4" if CONFIG_SH4A
265 default "" if CONFIG_386
266 default "i486" if CONFIG_486
267 default "i586" if CONFIG_586
268 default "i686" if CONFIG_686
271 source "extra/Configs/Config.in.arch"
275 menu "General Library Settings"
281 bool "Generate only Position Independent Code (PIC)"
283 depends on !HAVE_NO_PIC
285 If you wish to build all of uClibc as PIC objects, then answer Y here.
286 If you are unsure, then you should answer N.
288 config ARCH_HAS_NO_SHARED
291 config ARCH_HAS_NO_LDSO
293 select ARCH_HAS_NO_SHARED
295 config ARCH_HAS_UCONTEXT
299 bool "Enable shared libraries"
300 depends on !ARCH_HAS_NO_SHARED
303 If you wish to build uClibc with support for shared libraries then
304 answer Y here. If you only want to build uClibc as a static library,
307 config FORCE_SHAREABLE_TEXT_SEGMENTS
308 bool "Only load shared libraries which can share their text segment"
309 depends on HAVE_SHARED
312 If you answer Y here, the uClibc native shared library loader will
313 only load shared libraries, which do not need to modify any
314 non-writable segments. These libraries haven't set the DT_TEXTREL
315 tag in the dynamic section (==> objdump).
316 All your libraries must be compiled with -fPIC or -fpic, and all
317 assembler function must be written as position independent code (PIC).
318 Enabling this option will make uClibc's shared library loader a
319 little bit smaller and guarantee that no memory will be wasted by
320 badly coded shared libraries.
322 config LDSO_LDD_SUPPORT
323 bool "Native 'ldd' support"
324 depends on HAVE_SHARED
327 Enable all the code needed to support traditional ldd,
328 which executes the shared library loader to resolve all dependencies
329 and then provide a list of shared libraries that are required for an
330 application to function. Disabling this option will make uClibc's
331 shared library loader a little bit smaller.
332 Most people will answer Y.
334 config LDSO_CACHE_SUPPORT
335 bool "Enable library loader cache (ld.so.conf)"
336 depends on HAVE_SHARED
339 Enable this to make use of /etc/ld.so.conf, the shared library loader
340 cache configuration file to support for non-standard library paths.
341 After updating this file, it is necessary to run 'ldconfig' to update
342 the /etc/ld.so.cache shared library loader cache file.
344 config LDSO_PRELOAD_ENV_SUPPORT
345 bool "Enable library loader LD_PRELOAD environment"
346 depends on HAVE_SHARED
349 Enable this to make use of LD_PRELOAD environment variable.
350 A whitespace-separated list of additional, user-specified, ELF shared
351 libraries to be loaded before all others. This can be used to
352 selectively override functions in other shared libraries. For
353 set-user-ID/set-group-ID ELF binaries, only libraries in the standard
354 search directories that are also set-user-ID will be loaded.
356 config LDSO_PRELOAD_FILE_SUPPORT
357 bool "Enable library loader preload file (ld.so.preload)"
358 depends on HAVE_SHARED
360 Enable this to make use of /etc/ld.so.preload. This file contains a
361 whitespace separated list of shared libraries to be loaded before
364 config LDSO_BASE_FILENAME
365 string "Shared library loader naming prefix"
366 depends on HAVE_SHARED && (LDSO_CACHE_SUPPORT || LDSO_PRELOAD_FILE_SUPPORT)
369 If you wish to support both uClibc and glibc on the same system, it
370 is necessary to set this to something other than "ld.so" to avoid
371 conflicts with glibc, which also uses "ld.so". This prevents both
372 libraries from using the same /etc/ld.so.* files. If you wish to
373 support both uClibc and glibc on the same system then you should set
374 this to "ld-uClibc.so".
376 Most people will leave this set to the default of "ld.so".
378 WARNING: Changing the default prefix could cause problems with
381 config LDSO_STANDALONE_SUPPORT
382 bool "Dynamic linker stand-alone mode support"
383 depends on HAVE_SHARED
385 The dynamic linker can be run either indirectly through running some
386 dynamically linked program or library (in which case no command line
387 options to the dynamic linker can be passed and, in the ELF case, the
388 dynamic linker which is stored in the .interp section of the program
389 is executed) or directly by running:
391 /lib/ld-uClibc.so.* [OPTIONS] [PROGRAM [ARGUMENTS]]
393 Stand-alone execution is a prerequisite for adding prelink
394 capabilities to uClibc dynamic linker, as well useful for testing an
395 updated version of the dynamic linker without breaking the system.
397 config LDSO_PRELINK_SUPPORT
398 bool "Dynamic linker prelink support"
399 depends on HAVE_SHARED
400 select LDSO_STANDALONE_SUPPORT
402 The dynamic linker can be used in stand-alone mode by the prelink tool
403 for prelinking ELF shared libraries and binaries to speed up startup
404 time. It also is able to load and handle prelinked libraries and
407 config UCLIBC_STATIC_LDCONFIG
408 bool "Link ldconfig statically"
409 depends on HAVE_SHARED
412 Enable this option to statically link the ldconfig binary.
414 Making ldconfig static can be beneficial if you have a library
415 problem and need to use ldconfig to recover. Sometimes it is
416 preferable to instead keep the size of the system down, in which
417 case you should disable this option.
420 bool "Enable ELF RUNPATH tag support"
421 depends on HAVE_SHARED
422 default y if LDSO_CACHE_SUPPORT
424 ELF's may have dynamic RPATH/RUNPATH tags. These tags list paths
425 which extend the library search paths. They are really only useful
426 if a package installs libraries in non standard locations and
427 ld.so.conf support is disabled.
429 Usage of RUNPATH tags is not too common, so disabling this feature
430 should be safe for most people.
432 config LDSO_RUNPATH_OF_EXECUTABLE
433 bool "Use executables RUNPATH/RPATH when searching for libraries."
434 depends on LDSO_RUNPATH
437 Use the executables RUNPATH/RPATH to find to find libraries even
438 though this behavour is not standard. Setting this option causes
439 the uclibc dynamic linker behavour to match the glibc dynamic linker.
441 config LDSO_SAFE_RUNPATH
442 bool "Allow only RUNPATH beginning with /"
443 depends on LDSO_RUNPATH
446 Allow only absolute path in RPATH/RUNPATH.
448 config LDSO_SEARCH_INTERP_PATH
449 bool "Add ldso path to lib search path"
450 depends on HAVE_SHARED
453 The ldso is told where it is being executed from and can use that
454 path to find related core libraries. This is useful by default,
455 but can be annoying in a mixed development environment.
457 i.e. if the ldso is run from /foo/boo/ldso.so, it will start its
458 library search with /foo/boo/
460 If unsure, simply say Y here.
462 config LDSO_LD_LIBRARY_PATH
463 bool "Add LD_LIBRARY_PATH to lib search path"
464 depends on HAVE_SHARED
467 On hardened system it could be useful to disable the use of
468 LD_LIBRARY_PATH environment variable (a colon-separated list of
469 directories in which to search for ELF libraries at execution-time).
471 If unsure, simply say Y here.
473 config UCLIBC_CTOR_DTOR
477 If you wish to build uClibc with support for global constructor
478 (ctor) and global destructor (dtor) support, then answer Y here.
479 When ctor/dtor support is enabled, binaries linked with uClibc must
480 also be linked with crtbegin.o and crtend.o which are provided by gcc
481 (the "*startfile:" and "*endfile:" settings in your gcc specs file
482 may need to be adjusted to include these files). This support will
483 also add a small amount of additional size to each binary compiled vs
484 uClibc. If you will be using uClibc with C++, or if you need the gcc
485 __attribute__((constructor)) and __attribute__((destructor)) to work,
486 then you definitely want to answer Y here. If you don't need ctors
487 or dtors and want your binaries to be as small as possible, then
490 config LDSO_GNU_HASH_SUPPORT
491 bool "Enable GNU hash style support"
492 depends on HAVE_SHARED
494 Newest binutils support a new hash style named GNU-hash. The dynamic
495 linker will use the new GNU-hash section (.gnu.hash) for symbol lookup
496 if present into the ELF binaries, otherwise it will use the old SysV
497 hash style (.hash). This ensures that it is completely backward
499 Further, being the hash table implementation self-contained into each
500 executable and shared libraries, objects with mixed hash style can
501 peacefully coexist in the same process.
503 If you want to use this new feature, answer Y
506 prompt "Thread support"
507 default HAS_NO_THREADS
509 If you want to compile uClibc with pthread support, then answer Y.
510 This will increase the size of uClibc by adding a bunch of locking
511 to critical data structures, and adding extra code to ensure that
512 functions are properly reentrant.
514 config HAS_NO_THREADS
517 Disable thread support.
519 config UCLIBC_HAS_LINUXTHREADS
521 # linuxthreads need nanosleep()
522 select UCLIBC_HAS_REALTIME
523 depends on !TARGET_aarch64 && \
526 If you want to compile uClibc with Linuxthreads support, then answer Y.
528 config UCLIBC_HAS_THREADS_NATIVE
529 bool "Native POSIX Threading (NPTL)"
530 select UCLIBC_HAS_TLS
531 select UCLIBC_HAS_STDIO_FUTEXES
532 select UCLIBC_HAS_REALTIME
533 # i386 has no lowlevellock support (yet) as opposed to i486 onward
534 depends on !CONFIG_386 && \
546 If you want to compile uClibc with NPTL support, then answer Y.
550 config UCLIBC_HAS_THREADS
551 def_bool y if !HAS_NO_THREADS
553 config UCLIBC_HAS_TLS
554 bool "Thread-Local Storage"
555 depends on UCLIBC_HAS_THREADS_NATIVE
557 If you want to enable TLS support then answer Y.
558 This is fast an efficient way to store per-thread local data
559 which is not on stack. It needs __thread support enabled in
562 config PTHREADS_DEBUG_SUPPORT
563 bool "Build pthreads debugging support"
564 depends on UCLIBC_HAS_THREADS
566 Say Y here if you wish to be able to debug applications that use
567 uClibc's pthreads library. By enabling this option, a library
568 named libthread_db will be built. This library will be dlopen()'d
569 by gdb and will allow gdb to debug the threads in your application.
571 IMPORTANT NOTE! Because gdb must dlopen() the libthread_db library,
572 you must compile gdb with uClibc in order for pthread debugging to
575 If you are doing development and want to debug applications using
576 uClibc's pthread library, answer Y. Otherwise, answer N.
579 config UCLIBC_HAS_SYSLOG
580 bool "Syslog support"
582 depends on UCLIBC_HAS_NETWORK_SUPPORT
583 select UCLIBC_HAS_SOCKET
585 Support sending messages to the system logger.
586 This requires socket-support.
588 config UCLIBC_HAS_LFS
591 Large file support (always enabled; config symbol retained for
592 feature test to be compatible with uClibc).
594 prompt "Malloc Implementation"
595 default MALLOC if ! ARCH_USE_MMU
596 default MALLOC_STANDARD if ARCH_USE_MMU
601 "malloc" use mmap for all allocations and so works very well on
602 MMU-less systems that do not support the brk() system call. It is
603 pretty smart about reusing already allocated memory, and minimizing
605 This is the default for uClinux MMU-less systems.
610 "malloc-simple" is trivially simple and slow as molasses. It
611 was written from scratch for uClibc, and is the simplest possible
612 (and therefore smallest) malloc implementation.
614 This uses only the mmap() system call to allocate and free memory,
615 and does not use the brk() system call at all, making it a fine
616 choice for MMU-less systems with very limited memory. It's 100%
617 standards compliant, thread safe, very small, and releases freed
618 memory back to the OS immediately rather than keeping it in the
619 process's heap for reallocation. It is also VERY SLOW.
621 config MALLOC_STANDARD
622 bool "malloc-standard"
623 depends on ARCH_USE_MMU
625 "malloc-standard" is derived from the public domain dlmalloc
626 implementation by Doug Lea. It is quite fast, and is pretty smart
627 about reusing already allocated memory, and minimizing memory
628 wastage. This uses brk() for small allocations, while using mmap()
629 for larger allocations. This is the default malloc implementation
632 If unsure, answer "malloc-standard".
636 config UCLIBC_DYNAMIC_ATEXIT
637 bool "Dynamic atexit() Support"
640 When this option is enabled, uClibc will support an infinite number,
641 of atexit() and on_exit() functions, limited only by your available
642 memory. This can be important when uClibc is used with C++, since
643 global destructors are implemented via atexit(), and it is quite
644 possible to exceed the default number when this option is disabled.
645 Enabling this option adds a few bytes, and more significantly makes
646 atexit and on_exit depend on malloc, which can be bad when compiling
649 Unless you use uClibc with C++, you should probably answer N.
651 config UCLIBC_HAS_UTMPX
652 bool "utmpx based support for tracking login/logouts to/from the system"
654 Answer y to enable support for accessing user accounting database.
655 It can be used to track all login/logout to the system.
657 config UCLIBC_HAS_UTMP
658 bool "utmp support (XPG2 compat, SVr4 compat)"
659 depends on UCLIBC_HAS_UTMPX
661 Answer y to enable legacy SVID support for accessing
662 user accounting database:
663 getutent(), getutid(), getutline(), pututline(),
664 setutent(), endutent(), utmpname() in utmp.h
665 It can be used to track all login/logout to the system.
667 If unsure, answer N and use corresponding POSIX functions
670 config UCLIBC_SUSV2_LEGACY
671 bool "Enable SuSv2 LEGACY functions"
673 Enable this option if you want to have SuSv2 LEGACY functions
674 Currently applies to:
678 WARNING! ABI incompatibility.
680 config UCLIBC_SUSV3_LEGACY
681 bool "Enable SuSv3 LEGACY functions"
687 Enable this option if you want to have SuSv3 LEGACY functions
688 in the library, else they are replaced by SuSv3 proposed macros.
689 Currently applies to:
691 bcmp, bcopy, bzero, index, rindex, ftime,
692 bsd_signal, (ecvt), (fcvt), gcvt, (getcontext),
693 (getwd), (makecontext),
694 mktemp, (pthread_attr_getstackaddr), (pthread_attr_setstackaddr),
695 scalb, (setcontext), (swapcontext), ualarm, usleep,
698 WARNING! ABI incompatibility.
700 config UCLIBC_HAS_CONTEXT_FUNCS
701 bool "Use obsolescent context control functions"
702 depends on UCLIBC_SUSV3_LEGACY && ARCH_HAS_UCONTEXT
704 Add into library the SuSv3 obsolescent functions used for context
705 control. The setcontext family allows the implementation in C of
706 advanced control flow patterns such as iterators, fibers, and
707 coroutines. They may be viewed as an advanced version of
708 setjmp/longjmp; whereas the latter allows only a single non-local jump
709 up the stack, setcontext allows the creation of multiple cooperative
710 threads of control, each with its own stack.
711 These functions are: setcontext, getcontext, makecontext, swapcontext.
713 config UCLIBC_SUSV3_LEGACY_MACROS
714 bool "Enable SuSv3 LEGACY macros"
716 Enable this option if you want to have SuSv3 LEGACY macros.
717 Currently applies to bcopy/bzero/bcmp/index/rindex et al.
718 WARNING! ABI incompatibility.
720 config UCLIBC_SUSV4_LEGACY
721 bool "Enable SuSv4 LEGACY or obsolescent functions"
723 Enable this option if you want to have SuSv4 LEGACY functions
724 and macros in the library.
725 Currently applies to:
728 _longjmp, _setjmp, _tolower, _toupper, ftw, getitimer,
729 gettimeofday, isascii, pthread_getconcurrency,
730 pthread_setconcurrency, setitimer, setpgrp, sighold,
731 sigignore, sigpause, sigrelse, sigset, siginterrupt,
732 tempnam, toascii, ulimit.
735 asctime, asctime_r, ctime, ctime_r, gets, rand_r,
738 WARNING! ABI incompatibility.
740 config UCLIBC_STRICT_HEADERS
741 bool "Hide structures and constants for unsupported features"
743 Hide structures and constants in headers that should not be used,
744 because the respective feature is disabled.
746 WARNING! enabling this option requires to patch many faulty apps,
747 since they make (wrongly) use of these structures/constants,
748 although the feature was disabled.
750 config UCLIBC_HAS_STUBS
751 bool "Provide stubs for unavailable functionality"
753 With this option uClibc provides non-functional stubs for
754 functions which are impossible to implement on the target
755 architecture. Otherwise, such functions are simply omitted.
757 config UCLIBC_HAS_SHADOW
758 bool "Shadow Password Support"
761 Answer N if you do not need shadow password support.
762 Most people will answer Y.
764 config UCLIBC_HAS_PROGRAM_INVOCATION_NAME
765 bool "Support for program_invocation_name"
767 Support for the GNU-specific program_invocation_name and
768 program_invocation_short_name strings. Some GNU packages
769 (like tar and coreutils) utilize these for extra useful
770 output, but in general are not required.
772 At startup, these external strings are automatically set
773 up based on the value of ARGV[0].
775 If unsure, just answer N.
777 config UCLIBC_HAS___PROGNAME
778 bool "Support for __progname"
781 Some packages (like openssh) like to peek into internal libc
782 symbols to make their output a bit more user friendly.
784 At startup, __progname is automatically set up based on the
787 If unsure, just answer N.
789 config UCLIBC_HAS_PTY
790 bool "Support for pseudo-terminals"
793 This enables support for pseudo-terminals (see man 4 pts
796 If unsure, just answer Y.
799 bool "Assume that /dev/pts is a devpts or devfs file system"
801 depends on UCLIBC_HAS_PTY
803 Enable this if /dev/pts is on a devpts or devfs filesystem. Both
804 these filesystems automatically manage permissions on the /dev/pts
805 devices. You may need to mount your devpts or devfs filesystem on
806 /dev/pts for this to work.
808 Most people should answer Y.
810 config UNIX98PTY_ONLY
811 bool "Support only Unix 98 PTYs"
813 depends on UCLIBC_HAS_PTY
815 If you want to support only Unix 98 PTYs enable this. Some older
816 applications may need this disabled and will thus use legacy BSD
817 style PTY handling which is more complex and also bigger than
818 Unix 98 PTY handling.
820 For most current programs, you can generally answer Y.
823 config UCLIBC_HAS_GETPT
824 bool "Support getpt() (glibc-compat)"
825 depends on UCLIBC_HAS_PTY
827 Some packages may need getpt().
828 All of those are non-standard and can be considered
829 GNU/libc compatibility.
830 Either use posix_openpt() or just open /dev/ptmx yourself.
832 If unsure, just say N.
836 # Have to use __libc_ptyname{1,2}[] and related bloat
837 config UCLIBC_HAS_GETPT
841 config UCLIBC_HAS_LIBUTIL
842 bool "Provide libutil library and functions"
843 depends on UCLIBC_HAS_PTY
845 Provide a libutil library.
846 This non-standard conforming library provides the following
849 forkpty(): combines openpty(), fork(2), and login_tty() to
850 create a new process operating in a pseudo-terminal.
851 login(): write utmp and wtmp entries
852 login_tty(): prepares for a login on the tty fd by creating a
853 new session, making fd the controlling terminal for
854 the calling process, setting fd to be the standard
855 input, output, and error streams of the current
856 process, and closing fd.
857 logout(): write utmp and wtmp entries
858 logwtmp(): constructs a utmp structure and calls updwtmp() to
859 append the structure to the utmp file.
860 openpty(): finds an available pseudo-terminal and returns
861 file descriptors for the master and slave
863 This library adds about 3k-4k to your system.
865 config UCLIBC_HAS_TM_EXTENSIONS
866 bool "Support 'struct tm' timezone extension fields"
869 Enabling this option adds fields to 'struct tm' in time.h for
870 tracking the number of seconds east of UTC, and an abbreviation for
871 the current timezone. These fields are not specified by the SuSv3
872 standard, but they are commonly used in both GNU and BSD application
875 To strictly follow the SuSv3 standard, leave this disabled.
876 Most people will probably want to answer Y.
878 config UCLIBC_HAS_TZ_CACHING
879 bool "Enable caching of the last valid timezone 'TZ' string"
882 Answer Y to enable caching of the last valid 'TZ' string describing
883 the timezone setting. This allows a quick string compare to avoid
884 repeated parsing of unchanged 'TZ' strings when tzset() is called.
886 Most people will answer Y.
888 config UCLIBC_HAS_TZ_FILE
889 bool "Enable '/etc/TZ' file support to set a default timezone (uClibc-specific)"
892 Answer Y to enable the setting of a default timezone for uClibc.
894 Ordinarily, uClibc gets the timezone information exclusively from the
895 'TZ' environment variable. In particular, there is no support for
896 the zoneinfo directory tree or the /etc/timezone file used by glibc.
898 With this option enabled, uClibc will use the value stored in the
899 file '/etc/TZ' (default path) to obtain timezone information if the
900 'TZ' environment variable is missing or has an invalid value. The
901 file consists of a single line (newline required) of text describing
902 the timezone in the format specified for the TZ environment variable.
904 Doing 'echo CST6CDT > /etc/TZ' is enough to create a valid file.
906 http://www.opengroup.org/onlinepubs/007904975/basedefs/xbd_chap08.html
907 for details on valid settings of 'TZ'.
909 Most people will answer Y.
911 config UCLIBC_HAS_TZ_FILE_READ_MANY
912 bool "Repeatedly read the '/etc/TZ' file"
913 depends on UCLIBC_HAS_TZ_FILE
916 Answer Y to enable repeated reading of the '/etc/TZ' file even after
917 a valid value has been read. This incurs the overhead of an
918 open/read/close for each tzset() call (explicit or implied). However,
919 setting this will allow applications to update their timezone
920 information if the contents of the file change.
922 Most people will answer Y.
924 config UCLIBC_TZ_FILE_PATH
925 string "Path to the 'TZ' file for setting the global timezone"
926 depends on UCLIBC_HAS_TZ_FILE
929 This is the path to the 'TZ' file.
931 Most people will use the default of '/etc/TZ'.
933 config UCLIBC_FALLBACK_TO_ETC_LOCALTIME
934 bool "Use /etc/localtime as a fallback"
935 depends on UCLIBC_HAS_TZ_FILE
938 Answer Y to try to use /etc/localtime file.
939 On glibc systems this file (if it is in TZif2 format)
940 contains timezone string at the end.
942 Most people will answer Y.
946 menu "Advanced Library Settings"
948 config UCLIBC_PWD_BUFFER_SIZE
949 int "Buffer size for getpwnam() and friends"
953 This sets the value of the buffer size for getpwnam() and friends.
954 By default, this is 256. (For reference, glibc uses 1024).
955 The value can be found using sysconf() with the _SC_GETPW_R_SIZE_MAX
958 config UCLIBC_GRP_BUFFER_SIZE
959 int "Buffer size for getgrnam() and friends"
963 This sets the value of the buffer size for getgrnam() and friends.
964 By default, this is 256. (For reference, glibc uses 1024).
965 The value can be found using sysconf() with the _SC_GETGR_R_SIZE_MAX
968 comment "Support various families of functions"
970 config UCLIBC_LINUX_SPECIFIC
971 bool "Linux specific functions"
974 accept4(), bdflush(),
975 capget(), capset(), eventfd(), fallocate(),
976 fstatfs(), getrandom(), inotify_*(), ioperm(), iopl(),
977 madvise(), modify_ldt(), pipe2(), personality(),
978 prctl()/arch_prctl(), pivot_root(), modify_ldt(),
979 ppoll(), readahead(), reboot(), remap_file_pages(),
980 sched_getaffinity(), sched_setaffinity(), sendfile(),
981 setfsgid(), setfsuid(), setresgid(), setresuid(),
982 splice(), vmsplice(), tee(), signalfd(), statfs(),
983 swapoff(), swapon(), sync_file_range(), syncfs(),
984 _sysctl(), sysinfo(), timerfd_*(), vhangup(), umount(),
987 config UCLIBC_HAS_GNU_ERROR
988 bool "Support GNU extensions for error-reporting"
991 Support for the GNU-specific error(), error_at_line(),
992 void (* error_print_progname)(), error_message_count
993 functions and variables. Some GNU packages
994 utilize these for extra useful output, but in general
997 If unsure, just answer N.
999 config UCLIBC_BSD_SPECIFIC
1000 bool "BSD specific functions"
1003 mincore(), getdomainname(), setdomainname()
1007 config UCLIBC_HAS_BSD_ERR
1008 bool "BSD err functions"
1011 These functions are non-standard BSD extensions.
1012 err(), errx(), warn(), warnx(), verr(), verrx(), vwarn(), vwarnx()
1016 config UCLIBC_HAS_OBSOLETE_BSD_SIGNAL
1017 bool "BSD obsolete signal functions"
1019 These functions are provided as a compatibility interface for
1020 programs that make use of the historical System V signal API.
1021 This API is obsolete:
1022 new applications should use the POSIX signal API (sigaction(2),
1023 sigprocmask(2), etc.).
1026 sigset(), sighold(), sigrelse(), sigignore()
1030 config UCLIBC_HAS_OBSOLETE_SYSV_SIGNAL
1031 bool "SYSV obsolete signal functions"
1033 Use of sysv_signal() should be avoided; use sigaction(2) instead.
1037 config UCLIBC_NTP_LEGACY
1038 bool "ntp_*() aliases"
1040 Provide legacy aliases for ntp functions:
1041 ntp_adjtime(), ntp_gettime()
1043 It is safe to say N here.
1045 config UCLIBC_SV4_DEPRECATED
1046 bool "Enable SVr4 deprecated functions"
1048 These functions are DEPRECATED in System V release 4.
1049 Say N unless you desparately need one of the functions below:
1051 ustat() [use statfs(2) in your code instead]
1053 config UCLIBC_HAS_REALTIME
1054 bool "Realtime-related family of SUSv functions"
1057 These functions are part of the Timers option and need not
1058 be available on all implementations.
1059 Includes AIO, message-queue, scheduler, semaphore functions:
1074 clock_getres(), clock_gettime(), clock_settime()
1076 mlockall(), munlockall()
1088 sched_get_priority_max(), sched_get_priority_min()
1089 sched_getscheduler()
1090 sched_rr_get_interval()
1092 sched_setscheduler()
1099 sem_trywait(), sem_wait()
1102 sigtimedwait(), sigwaitinfo()
1105 timer_getoverrun(), timer_gettime(), timer_settime()
1107 config UCLIBC_HAS_ADVANCED_REALTIME
1108 bool "Advanced realtime-related family of SUSv functions"
1110 depends on UCLIBC_HAS_REALTIME
1112 These functions are part of the Timers option and need not
1113 be available on all implementations.
1115 clock_getcpuclockid()
1124 posix_spawnattr_destroy(), posix_spawnattr_init()
1125 posix_spawnattr_getflags(), posix_spawnattr_setflags()
1126 posix_spawnattr_getpgroup(), posix_spawnattr_setpgroup()
1127 posix_spawnattr_getschedparam(), posix_spawnattr_setschedparam()
1128 posix_spawnattr_getschedpolicy(), posix_spawnattr_setschedpolicy()
1129 posix_spawnattr_getsigdefault(), posix_spawnattr_setsigdefault()
1130 posix_spawnattr_getsigmask(), posix_spawnattr_setsigmask()
1131 posix_spawn_file_actions_addclose()
1132 posix_spawn_file_actions_adddup2()
1133 posix_spawn_file_actions_addopen()
1134 posix_spawn_file_actions_destroy()
1135 posix_spawn_file_actions_init()
1138 posix_typed_mem_get_info()
1139 pthread_mutex_timedlock()
1142 #config UCLIBC_HAS_TERMIOS
1143 # bool "termios functions"
1146 # Get and set terminal attributes, line control, get and set baud
1148 # termios(), tcgetattr(), tcsetattr(), tcsendbreak(), tcdrain(),
1149 # tcflush(), tcflow(), cfmakeraw(), cfgetospeed(), cfgetispeed(),
1150 # cfsetispeed(), cfsetospeed(), cfsetspeed()
1154 config UCLIBC_HAS_EPOLL
1158 epoll_create(), epoll_ctl(), epoll_wait() functions.
1160 config UCLIBC_HAS_XATTR
1161 bool "Extended Attributes"
1164 Extended Attributes support.
1179 Say N unless you need support for extended attributes and the
1180 filesystems do actually support them.
1182 config UCLIBC_HAS_PROFILING
1183 bool "Profiling support"
1186 gcc's -finstrument-functions needs these.
1188 Most people can safely answer N.
1190 config UCLIBC_HAS_CRYPT_IMPL
1191 bool "libcrypt support"
1194 libcrypt contains crypt(), setkey() and encrypt()
1196 config UCLIBC_HAS_SHA256_CRYPT_IMPL
1197 bool "libcrypt SHA256 support"
1198 depends on UCLIBC_HAS_CRYPT_IMPL
1200 This adds support for SHA256 password hashing via the crypt() function.
1201 Say N here if you do not need SHA256 crypt support.
1203 config UCLIBC_HAS_SHA512_CRYPT_IMPL
1204 bool "libcrypt SHA512 support"
1205 depends on UCLIBC_HAS_CRYPT_IMPL
1207 This adds support for SHA512 password hashing via the crypt() function.
1208 Say N here if you do not need SHA512 crypt support.
1210 config UCLIBC_HAS_CRYPT_STUB
1211 bool "libcrypt stubs"
1213 depends on !UCLIBC_HAS_CRYPT_IMPL
1215 Standards mandate that crypt(3) provides a stub if it is unavailable.
1216 If you enable this option then stubs for
1217 crypt(), setkey() and encrypt()
1218 will be provided in a small libcrypt.
1220 config UCLIBC_HAS_CRYPT
1222 depends on UCLIBC_HAS_CRYPT_IMPL || UCLIBC_HAS_CRYPT_STUB
1225 menuconfig UCLIBC_HAS_NETWORK_SUPPORT
1226 bool "Networking Support"
1229 Say N here if you do not need network support.
1231 if UCLIBC_HAS_NETWORK_SUPPORT
1232 config UCLIBC_HAS_SOCKET
1233 bool "Socket support"
1236 If you want to include support for sockets then answer Y.
1238 config UCLIBC_HAS_IPV4
1239 bool "IP version 4 support"
1241 select UCLIBC_HAS_SOCKET
1243 If you want to include support for the Internet Protocol
1244 (IP version 4) then answer Y.
1246 Most people will say Y.
1248 config UCLIBC_HAS_IPV6
1249 bool "IP version 6 support"
1250 select UCLIBC_HAS_SOCKET
1252 If you want to include support for the next version of the Internet
1253 Protocol (IP version 6) then answer Y.
1255 Most people should answer N.
1257 config UCLIBC_USE_NETLINK
1258 bool "Use netlink to query interfaces"
1259 depends on UCLIBC_HAS_SOCKET
1261 In newer versions of Linux (2.4.17+), support was added for querying
1262 network device information via netlink rather than the old style
1263 ioctl's. Most of the time, the older ioctl style is sufficient (and
1264 it is smaller than netlink), but if you find that not all of your
1265 devices are being returned by the if_nameindex() function, you will
1266 have to use the netlink implementation.
1268 Most people can safely answer N.
1270 config UCLIBC_SUPPORT_AI_ADDRCONFIG
1271 bool "Support the AI_ADDRCONFIG flag"
1272 depends on UCLIBC_USE_NETLINK
1274 The implementation of AI_ADDRCONFIG is aligned with the glibc
1275 implementation using netlink to query interfaces to find both
1276 ipv4 and ipv6 support. This is only needed if an application uses
1277 the AI_ADDRCONFIG flag.
1279 Most people can safely answer N.
1281 config UCLIBC_HAS_BSD_RES_CLOSE
1282 bool "Support res_close() (bsd-compat)"
1284 Answer Y if you desperately want to support BSD compatibility in
1287 Most people will say N.
1289 config UCLIBC_HAS_COMPAT_RES_STATE
1290 bool "Use compatible but bloated _res"
1293 Answer Y if you build network utilities and they muck with resolver
1294 internals a lot (_res global structure). uclibc does not use most
1295 of _res.XXX fields, and with this option OFF they won't even exist.
1296 Which will make e.g. dig build fail.
1297 Answering N saves around 400 bytes in bss.
1299 config UCLIBC_HAS_EXTRA_COMPAT_RES_STATE
1300 bool "Use extra compatible but extra bloated _res"
1302 Answer Y if selecting UCLIBC_HAS_COMPAT_RES_STATE is not enough.
1303 As far as I can say, this should never be needed.
1305 config UCLIBC_HAS_RESOLVER_SUPPORT
1306 bool "DNS resolver functions"
1307 select UCLIBC_HAS_COMPAT_RES_STATE
1308 depends on UCLIBC_HAS_IPV4 || UCLIBC_HAS_IPV6
1310 Provide implementations for DNS resolver functions.
1311 In particular, the following functions will be added to the
1314 ns_skiprr, ns_initparse, ns_parserr, ns_msg_getflag,
1315 res_mkquery, res_init, res_ninit, res_close, res_nclose
1316 res_query, res_search, res_querydomain,
1318 ns_name_uncompress, ns_name_ntop, ns_name_pton, ns_name_unpack,
1319 ns_name_pack, ns_name_compress, ns_name_skip, dn_skipname,
1320 ns_get16, ns_get32, ns_put16, ns_put32
1325 menu "String and Stdio Support"
1327 config UCLIBC_HAS_STRING_GENERIC_OPT
1328 bool "Use faster (but larger) generic string functions"
1331 Answer Y to use the (tweaked) glibc generic string functions.
1333 In general, they are faster (but 3-5K larger) than the base
1334 uClibc string functions which are optimized solely for size.
1336 Many people will answer Y.
1338 config UCLIBC_HAS_STRING_ARCH_OPT
1339 bool "Use arch-specific assembly string functions (where available)"
1342 Answer Y to use any archtecture-specific assembly language string
1343 functions available for this target plaform.
1345 Note that assembly implementations are not available for all string
1346 functions, so some generic (written in C) string functions may
1349 These are small and fast, the only reason _not_ to say Y here is
1350 for debugging purposes.
1352 config UCLIBC_HAS_STDIO_FUTEXES
1353 bool "Use futexes for multithreaded I/O locking"
1354 depends on UCLIBC_HAS_THREADS_NATIVE
1356 If you want to compile uClibc to use futexes for low-level
1357 I/O locking, answer Y. Otherwise, answer N.
1359 config UCLIBC_HAS_CTYPE_TABLES
1360 bool "Use Table Versions Of 'ctype.h' Functions."
1363 Answer Y to use table versions of the 'ctype.h' functions.
1364 While the non-table versions are often smaller when building
1365 statically linked apps, they work only in stub locale mode.
1367 Most people will answer Y.
1369 config UCLIBC_HAS_CTYPE_SIGNED
1370 bool "Support Signed Characters In 'ctype.h' Functions."
1371 depends on UCLIBC_HAS_CTYPE_TABLES
1374 Answer Y to enable support for passing signed char values to
1375 the 'ctype.h' functions. ANSI/ISO C99 and SUSv3 specify that
1376 these functions are only defined for unsigned char values and
1377 EOF. However, glibc allows negative signed char values as well
1378 in order to support 'broken old programs'.
1380 Most people will answer Y.
1383 prompt "ctype argument checking"
1384 depends on UCLIBC_HAS_CTYPE_TABLES
1385 default UCLIBC_HAS_CTYPE_UNSAFE
1387 Please select the invalid arg behavior you want for the 'ctype'
1390 The 'ctype' functions are now implemented using table lookups, with
1391 the arg being the index. This can result in incorrect memory accesses
1392 or even segfaults for args outside of the allowed range.
1394 NOTE: This only affects the 'ctype' _functions_. It does not affect
1395 the macro implementations.
1397 config UCLIBC_HAS_CTYPE_UNSAFE
1398 bool "Do not check -- unsafe"
1400 config UCLIBC_HAS_CTYPE_CHECKED
1401 bool "Detect and handle appropriately"
1403 config UCLIBC_HAS_CTYPE_ENFORCED
1404 bool "Issue a diagnostic and abort()"
1409 config UCLIBC_HAS_WCHAR
1410 bool "Wide Character Support"
1412 Answer Y to enable wide character support. This will make uClibc
1413 much larger. It is also currently required for locale support.
1415 Most people will answer N.
1417 config UCLIBC_HAS_LIBICONV
1418 bool "Iconv Support"
1419 select UCLIBC_HAS_WCHAR
1421 Add tiny iconv support for charset conversion from and to UTF-8.
1423 config UCLIBC_HAS_LIBINTL
1424 bool "Intl stubs support"
1426 If you enable this option you get stubs for the gettext family of
1429 config UCLIBC_HAS_LOCALE
1430 bool "Locale Support"
1431 select UCLIBC_HAS_WCHAR
1432 select UCLIBC_HAS_CTYPE_TABLES
1433 select UCLIBC_HAS_LIBICONV
1435 uClibc now has full ANSI/ISO C99 locale support (except for
1436 wcsftime() and collating items in regex). Be aware that enabling
1437 this option will make uClibc much larger.
1439 Enabling UCLIBC_HAS_LOCALE with the default set of supported locales
1440 (169 UTF-8 locales, and 144 locales for other codesets) will enlarge
1441 uClibc by around 300k. You can reduce this size by building your own
1442 custom set of locate data (see extra/locale/LOCALES for details).
1444 uClibc's locale support is still under development. For example,
1445 codesets using shift states are not currently supported. Support is
1446 planned in the next iteration of locale support.
1448 Answer Y to enable locale support. Most people will answer N.
1452 prompt "Locale data"
1453 depends on UCLIBC_HAS_LOCALE
1454 default UCLIBC_BUILD_MINIMAL_LOCALE
1456 config UCLIBC_BUILD_MINIMAL_LOCALE
1457 bool "Only selected locales"
1458 depends on UCLIBC_HAS_LOCALE
1460 If you do not need all locales that are available on your
1461 host-box, then set this to 'Y'.
1463 config UCLIBC_BUILD_ALL_LOCALE
1465 depends on UCLIBC_HAS_LOCALE
1467 This builds all the locales that are available on your
1472 config UCLIBC_BUILD_MINIMAL_LOCALES
1473 string "locales to use"
1474 depends on UCLIBC_BUILD_MINIMAL_LOCALE
1477 Space separated list of locales to use.
1484 config UCLIBC_HAS_XLOCALE
1485 bool "Extended Locale Support (experimental/incomplete)"
1486 depends on UCLIBC_HAS_LOCALE
1488 Answer Y to enable extended locale support similar to that provided
1489 by glibc. This is primarily intended to support libstd++
1491 However, it also allows thread-specific locale selection via
1494 Most people will answer N.
1496 config UCLIBC_HAS_HEXADECIMAL_FLOATS
1497 bool "Support hexadecimal float notation"
1498 depends on UCLIBC_HAS_CTYPE_TABLES
1499 depends on UCLIBC_HAS_FLOATS
1501 Answer Y to enable support for hexadecimal float notation in the
1502 (wchar and) char string to floating point conversion functions, as
1503 well as support for the %a and %A conversion specifiers in the
1504 *printf() and *scanf() functions.
1506 Most people will answer N.
1508 config UCLIBC_HAS_GLIBC_DIGIT_GROUPING
1509 bool "Support glibc's \"'\" flag for allowing locale-specific digit grouping"
1510 depends on UCLIBC_HAS_LOCALE
1511 depends on UCLIBC_HAS_FLOATS
1513 Answer Y to enable support for glibc's \"'\" flag for allowing
1514 locale-specific digit grouping in base 10 integer conversions and
1515 appropriate floating point conversions in the *printf() and *scanf()
1518 Most people will answer N.
1520 config UCLIBC_HAS_SCANF_LENIENT_DIGIT_GROUPING
1521 bool "Do not require digit grouping when the \"'\" flag is specified"
1522 depends on UCLIBC_HAS_GLIBC_DIGIT_GROUPING
1525 Answer Y to make digit grouping optional when the \"'\" flag is
1527 This is the standard glibc behavior. If the initial string of digits
1528 exceeds the maximum group number, the input will be treated as a
1529 normal non-grouped number.
1531 Most people will answer N.
1533 config UCLIBC_HAS_GLIBC_CUSTOM_PRINTF
1534 bool "Support glibc's register_printf_function() (glibc-compat)"
1535 depends on !USE_OLD_VFPRINTF
1537 Answer Y to support glibc's register_printf_function() to allow an
1538 application to add its own printf conversion specifiers.
1539 parse_printf_format() is also enabled.
1541 NOTE: Limits the number or registered specifiers to 10.
1542 NOTE: Requires new conversion specifiers to be ASCII
1543 characters (0-0x7f). This is to avoid problems with processing
1544 format strings in locales with different multibyte conversions.
1546 Most people will answer N.
1548 config USE_OLD_VFPRINTF
1549 bool "Use the old vfprintf implementation"
1550 depends on !UCLIBC_HAS_WCHAR
1552 Set to true to use the old vfprintf instead of the new. This is
1553 roughly C89 compliant with some extensions, and is much smaller.
1554 However, it does not support wide chars, positional args, or glibc
1555 custom printf specifiers.
1557 Most people will answer N.
1559 config UCLIBC_PRINTF_SCANF_POSITIONAL_ARGS
1560 int "Maximum number of positional args. Either 0 or >= 9."
1561 depends on !USE_OLD_VFPRINTF
1564 Set the maximum number of positional args supported by the
1565 printf/scanf functions. The Single Unix Specification Version 3
1566 requires a minimum value of 9. Setting this to a value lower than
1567 9 will disable positional arg support and cause the NL_ARGMAX macro
1568 in limits.h to be #undef'd.
1570 WARNING! The workspace to support positional args is currently
1571 allocated on the stack. You probably don't want to set
1572 this to too high a value.
1574 Most people will answer 9.
1577 prompt "Stdio buffer size"
1578 default UCLIBC_HAS_STDIO_BUFSIZ_4096
1580 Please select a value for BUFSIZ. This will be used by the
1581 stdio subsystem as the default buffer size for a file, and
1582 affects fopen(), setvbuf(), etc.
1584 NOTE: Setting this to 'none' will disable buffering completely.
1585 However, BUFSIZ will still be defined in stdio.h as 256 because
1586 many applications use this value.
1588 config UCLIBC_HAS_STDIO_BUFSIZ_NONE
1589 bool "none (WARNING - BUFSIZ will be 256 in stdio.h)"
1590 depends on !UCLIBC_HAS_WCHAR
1592 config UCLIBC_HAS_STDIO_BUFSIZ_256
1593 bool "256 (minimum ANSI/ISO C99 value)"
1595 config UCLIBC_HAS_STDIO_BUFSIZ_512
1598 config UCLIBC_HAS_STDIO_BUFSIZ_1024
1601 config UCLIBC_HAS_STDIO_BUFSIZ_2048
1604 config UCLIBC_HAS_STDIO_BUFSIZ_4096
1607 config UCLIBC_HAS_STDIO_BUFSIZ_8192
1610 # If you add more choices, you will need to update uClibc_stdio.h.
1615 prompt "Stdio builtin buffer size (uClibc-specific)"
1616 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1617 default UCLIBC_HAS_STDIO_BUILTIN_BUFFER_NONE
1619 When a FILE is created with fopen(), an attempt is made to allocate
1620 a BUFSIZ buffer for it. If the allocation fails, fopen() will still
1621 succeed but the FILE will be unbuffered.
1623 This option adds a small amount of space to each FILE to act as an
1624 emergency buffer in the event of a buffer allocation failure.
1626 Most people will answer None.
1628 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_NONE
1631 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_4
1634 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_8
1637 # If you add more choices, you will need to update uClibc_stdio.h.
1641 config UCLIBC_HAS_STDIO_SHUTDOWN_ON_ABORT
1642 bool "Attempt to shutdown stdio subsystem when abort() is called."
1644 ANSI/ISO C99 requires abort() to be asyn-signal-safe. So there was
1645 a behavioral change made in SUSv3. Previously, abort() was required
1646 to have the affect of fclose() on all open streams. The wording has
1647 been changed to "may" from "shall".
1649 Most people will answer N.
1651 config UCLIBC_HAS_STDIO_GETC_MACRO
1652 bool "Provide a macro version of getc()"
1653 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1656 Provide a macro version of getc().
1658 Most people will answer Y.
1660 config UCLIBC_HAS_STDIO_PUTC_MACRO
1661 bool "Provide a macro version of putc()"
1662 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1665 Provide a macro version of putc().
1667 Most people will answer Y.
1669 config UCLIBC_HAS_STDIO_AUTO_RW_TRANSITION
1670 bool "Support auto-r/w transition"
1673 Answer Y to enable the stdio subsystem to automaticly transition
1674 between reading and writing. This relaxes the ANSI/ISO C99
1677 When a file is opened with update mode ('+' as the second or third
1678 character in the list of mode argument values), both input and output
1679 may be performed on the associated stream. However, output shall not
1680 be directly followed by input without an intervening call to the
1681 fflush function or to a file positioning function (fseek, fsetpos,
1682 or rewind), and input shall not be directly followed by output without
1683 an intervening call to a file positioning function, unless the input
1684 operation encounters endÂofÂfile.
1686 Most people will answer Y.
1688 config UCLIBC_HAS_FOPEN_LARGEFILE_MODE
1689 bool "Support an fopen() 'F' flag for large file mode (uClibc-specific)"
1691 Answer Y to enable a uClibc-specific extension to allow passing an
1692 additional 'F' flag in the mode string for fopen() to specify that
1693 the file should be open()ed with the O_LARGEFILE flag set.
1695 Most people will answer N.
1697 config UCLIBC_HAS_FOPEN_EXCLUSIVE_MODE
1698 bool "Support an fopen() 'x' flag for exclusive mode (glibc-compat)"
1700 Answer Y to support a glibc extension to allow passing
1701 additional 'x' flag in the mode string for fopen() to specify that
1702 the file should be open()ed with the O_EXCL flag set.
1704 Most people will answer N.
1706 config UCLIBC_HAS_FOPEN_CLOSEEXEC_MODE
1707 bool "Support an fopen() 'e' flag for close-on-exec mode (glibc-compat)"
1709 Answer Y to support a glibc extension to allow passing
1710 additional 'e' flag in the mode string for fopen() to specify that
1711 the file should be open()ed with the O_CLOEXEC flag set.
1713 Most people will answer N.
1715 config UCLIBC_HAS_GLIBC_CUSTOM_STREAMS
1716 bool "Support fmemopen(), open_memstream(), and fopencookie() (glibc-compat)"
1718 Answer Y to support the glibc 'custom stream' extension functions
1719 fmemopen(), open_memstream(), and fopencookie().
1721 NOTE: There are some minor differences regarding seeking behavior.
1723 Most people will answer N.
1725 config UCLIBC_HAS_PRINTF_M_SPEC
1726 bool "Support the '%m' specifier in printf format strings (glibc-compat)"
1728 Answer Y to support a glibc extension to interpret '%m' in printf
1729 format strings as an instruction to output the error message string
1730 (as generated by strerror) corresponding to the current value of
1733 Most people will answer N.
1735 config UCLIBC_HAS_ERRNO_MESSAGES
1736 bool "Include the errno message text in the library"
1739 Answer Y if you want to include the errno message text in the
1740 library. This adds about 3K to the library, but enables strerror()
1741 to generate text other than 'Unknown error <number>'.
1743 Most people will answer Y.
1745 config UCLIBC_HAS_SYS_ERRLIST
1746 bool "Support sys_errlist[] (obsolete-compat)"
1747 depends on UCLIBC_HAS_ERRNO_MESSAGES
1749 Answer Y if you want to support the obsolete sys_errlist[].
1750 This adds about 0.5k to the library, except for the mips
1751 arch where it adds over 4K.
1753 WARNING! In the future, support for sys_errlist[] may be unavailable
1754 in at least some configurations. In fact, it may be removed
1757 Most people will answer N.
1759 Application writers: use the strerror(3) function.
1761 config UCLIBC_HAS_SIGNUM_MESSAGES
1762 bool "Include the signum message text in the library"
1765 Answer Y if you want to include the signum message text in the
1766 library. This adds about 0.5K to the library, but enables strsignal()
1767 to generate text other than 'Unknown signal <number>'.
1769 Most people will answer Y.
1771 config UCLIBC_HAS_SYS_SIGLIST
1772 bool "Support sys_siglist[] (bsd-compat)"
1773 depends on UCLIBC_HAS_SIGNUM_MESSAGES
1775 Answer Y if you want to support sys_siglist[].
1777 WARNING! In the future, support for sys_siglist[] may be unavailable
1778 in at least some configurations. In fact, it may be removed
1781 Most people will answer N.
1783 config UCLIBC_HAS_GNU_GETOPT
1784 bool "Support gnu getopt"
1787 Answer Y if you want to include full gnu getopt() instead of a
1788 (much smaller) SUSv3 compatible getopt().
1789 Note that getopt_long, getopt_long_only as well as getsubopt
1790 are implemented on top of this choice.
1792 Most people will answer Y.
1794 config UCLIBC_HAS_GETOPT_LONG
1795 bool "Support getopt_long/getopt_long_only (glibc-compat)"
1798 Answer Y if you want to include getopt_long[_only()] used by many
1801 Most people will answer Y.
1803 config UCLIBC_HAS_GNU_GETSUBOPT
1804 bool "Support getsubopt"
1807 Answer Y if you want to include getsubopt().
1809 Most people will answer Y.
1811 config UCLIBC_HAS_ARGP
1813 select UCLIBC_HAS_GETOPT_LONG
1814 select UCLIBC_HAS_GNU_GETOPT
1815 select UCLIBC_HAS_WCHAR
1818 Argp is an interface for parsing unix-style argument vectors. Unlike
1819 the common getopt interface, it provides many advanced features in
1820 addition to parsing options, such as automatic output in response to
1821 `--help' and `--version' options.
1822 A library can export an argp option parser, which programs can easily
1823 use in conjunction with their own option parser.
1824 Argp support is needed by elfutils libdw.
1826 Most people can safely answer N.
1833 config UCLIBC_HAS_REGEX
1834 bool "Regular Expression Support"
1837 POSIX regular expression code is really big -- 53k all by itself.
1838 If you don't use regular expressions, turn this off and save space.
1839 Of course, if you only statically link, leave this on, since it will
1840 only be included in your apps if you use regular expressions.
1842 config UCLIBC_HAS_FNMATCH
1843 bool "fnmatch Support"
1848 config UCLIBC_HAS_WORDEXP
1849 bool "Support the wordexp() interface"
1850 depends on UCLIBC_HAS_GLOB
1852 The SuSv3 wordexp() interface performs word expansions per the Shell
1853 and Utilities volume of IEEE Std 1003.1-2001, Section 2.6. It is
1854 intended for use by applications that want to implement all of the
1855 standard Bourne shell expansions on input data.
1857 This interface is rarely used, and very large. Unless you have a
1858 pressing need for wordexp(), you should probably answer N.
1860 config UCLIBC_HAS_NFTW
1861 bool "Support the nftw() interface"
1863 The SuSv3 nftw() interface is used to recursively descend
1864 directory paths while repeatedly calling a function.
1866 This interface is rarely used, and adds around 4.5k. Unless you have
1867 a pressing need for nftw(), you should probably answer N.
1869 config UCLIBC_HAS_FTW
1870 bool "Support the ftw() interface (SUSv4-obsolete)"
1871 depends on UCLIBC_SUSV4_LEGACY
1873 The SuSv3 ftw() interface is used to recursively descend
1874 directory paths while repeatedly calling a function.
1876 This interface is rarely used, and adds around 4.5k. Unless you have
1877 a pressing need for ftw(), you should probably answer N.
1879 config UCLIBC_HAS_FTS
1880 bool "Support the fts() interface (bsd-compat)"
1882 The fts functions are provided for traversing UNIX file hierarchies.
1884 This interface is currently used by the elfutils and adds
1886 You should port your application to use the POSIX nftw()
1889 Unless you need to build/use elfutils, you should prolly answer N.
1891 config UCLIBC_HAS_GLOB
1892 bool "Support the glob() interface"
1893 depends on UCLIBC_HAS_FNMATCH
1897 The glob interface is somewhat large (weighing in at about 2,5k). It
1898 is used fairly often, but is an option since people wanting to go for
1899 absolute minimum size may wish to omit it.
1901 Most people will answer Y.
1903 config UCLIBC_HAS_GNU_GLOB
1904 bool "Support gnu glob() interface"
1905 depends on UCLIBC_HAS_GLOB
1907 The gnu glob interface is somewhat larger (weighing in at about 4,2k)
1908 than it's SuSv3 counterpart (and is out of date). It is an old copy
1909 from glibc and does not support all the GNU specific options.
1911 Answer Y if you want to include full gnu glob() instead of the smaller
1912 SUSv3 compatible glob().
1914 Most people will answer N.
1921 menu "Library Installation Options"
1923 config RUNTIME_PREFIX
1924 string "uClibc runtime library directory"
1925 default "/usr/$(TARGET_ARCH)-linux-uclibc/"
1927 RUNTIME_PREFIX is the directory into which the uClibc runtime
1928 libraries will be installed. The result will look something
1931 lib/ <contains all runtime libraries>
1932 usr/bin/ldd <the ldd utility program>
1933 sbin/ldconfig <the ldconfig utility program>
1934 This value is used by the 'make install' Makefile target. Since this
1935 directory is compiled into the shared library loader, you will need to
1936 recompile uClibc if you change this value...
1938 For a typical target system this should be set to "/", such that
1939 'make install' will install /lib/libuClibc-<VERSION>.so
1942 string "uClibc development environment directory"
1943 default "/usr/$(TARGET_ARCH)-linux-uclibc/usr/"
1945 DEVEL_PREFIX is the directory into which the uClibc development
1946 environment will be installed. The result will look something
1949 lib/ <contains static libs>
1950 include/ <Where all the header files go>
1951 This value is used by the 'make install' Makefile target when
1952 installing a uClibc development environment.
1954 For a typical target system this should be set to "/usr", such that
1955 'make install' will install /usr/include/<header files>.
1958 string "library path component"
1961 Path component where libraries reside.
1963 For a typical target system this should be set to "lib", such that
1964 'make install' will install libraries to "/lib" and "/usr/lib"
1966 DEVEL_PREFIX/MULTILIB_DIR
1967 RUNTIME_PREFIX/MULTILIB_DIR
1969 Other settings may include "lib32" or "lib64".
1971 config HARDWIRED_ABSPATH
1972 bool "Hardwire absolute paths into linker scripts"
1975 This prepends absolute paths to the libraries mentioned in linker
1976 scripts such as libc.so.
1978 This is a build time optimization. It has no impact on dynamic
1979 linking at runtime, which doesn't use linker scripts.
1981 You must disable this to use uClibc with old non-sysroot toolchains,
1982 such as the prebuilt binary cross compilers at:
1983 http://uclibc.org/downloads/binaries
1985 The amount of time saved by this optimization is actually too small to
1986 measure. The linker just had to search the library path to find the
1987 linker script, so the dentries are cache hot if it has to search the
1988 same path again. But it's what glibc does, so we do it too.
1993 menu "Security options"
1995 config UCLIBC_BUILD_PIE
1996 bool "Build utilities as ET_DYN/PIE executables"
1997 depends on HAVE_SHARED
1998 depends on TARGET_arm || TARGET_frv || TARGET_i386 || TARGET_mips || TARGET_powerpc || TARGET_nds32
1999 select FORCE_SHAREABLE_TEXT_SEGMENTS
2001 If you answer Y here, ldd and iconv are built as ET_DYN/PIE
2004 It requires gcc-3.4 and binutils-2.15 (for arm 2.16) or later.
2005 More about ET_DYN/PIE binaries on <http://pax.grsecurity.net/> .
2007 WARNING: This option also enables FORCE_SHAREABLE_TEXT_SEGMENTS, so
2008 all libraries have to be built with -fPIC or -fpic, and all
2009 assembler functions must be written as position independent
2015 config UCLIBC_HAS_SSP
2016 bool "Support for GCC stack smashing protector"
2017 depends on !HAVE_NO_SSP
2019 Add code to support GCC's -fstack-protector[-all] option to uClibc.
2020 This requires GCC 4.1 or newer. GCC does not have to provide libssp,
2021 the needed functions are added to ldso/libc instead.
2023 GCC's stack protector is a reimplementation of IBM's propolice.
2024 See http://www.trl.ibm.com/projects/security/ssp/ and
2025 http://www.linuxfromscratch.org/hints/downloads/files/ssp.txt
2028 Note that NOEXECSTACK on a kernel with address space randomization
2029 is generally sufficient to prevent most buffer overflow exploits
2030 without increasing code size. This option essentially adds debugging
2033 Most people will answer N.
2035 config SSP_QUICK_CANARY
2036 bool "Use simple guard values without accessing /dev/urandom"
2037 depends on UCLIBC_HAS_SSP
2039 Use gettimeofday(2) to define the __guard without accessing
2041 WARNING: This makes smashing stack protector vulnerable to timing
2043 Most people will answer N.
2046 prompt "Propolice protection blocking signal"
2047 depends on UCLIBC_HAS_SSP
2049 default PROPOLICE_BLOCK_SEGV
2051 "abort" use SIGABRT to block offending programs.
2052 This is the default implementation.
2054 "segfault" use SIGSEGV to block offending programs.
2055 Use this for debugging.
2057 If unsure, answer "abort".
2059 config PROPOLICE_BLOCK_ABRT
2062 config PROPOLICE_BLOCK_SEGV
2067 config UCLIBC_BUILD_SSP
2068 bool "Build uClibc with -fstack-protector"
2069 depends on UCLIBC_HAS_SSP
2071 Build all uClibc libraries and executables with -fstack-protector,
2072 adding extra stack overflow checking to most uClibc functions.
2074 config UCLIBC_BUILD_RELRO
2075 bool "Build uClibc with linker option -z RELRO"
2076 depends on HAVE_SHARED
2079 Build all libraries and executables with "ld -z relro".
2081 This tells the linker to mark chunks of an executable or shared
2082 library read-only after applying dynamic relocations. (This comes
2083 up when a global const variable is initialized to the address of a
2084 function or the value of another global variable.)
2086 This is a fairly obscure option the ld man page doesn't even bother
2087 to document properly. It's a security paranoia issue that's more
2088 likely to consume memory (by allocating an extra page) rather than
2091 This is explained in more depth at
2092 http://www.airs.com/blog/archives/189
2094 Nobody is likely to care whether you say Y or N here.
2096 config UCLIBC_BUILD_NOW
2097 bool "Build uClibc with linker option -z NOW"
2098 depends on HAVE_SHARED
2100 Build all libraries and executables with "ld -z now".
2102 This tells the linker to resolve all symbols when the library is
2103 first loaded, rather than when each function is first called. This
2104 increases start-up latency by a few microseconds and may do
2105 unnecessary work (resolving symbols that are never used), but the
2106 realtime people like it for making microbenchmark timings slightly
2107 more predictable and in some cases it can be slightly faster due to
2108 CPU cache behavior (not having to fault the linker back in to do
2109 lazy symbol resolution).
2111 Most people can't tell the difference between selecting Y or N here.
2113 config UCLIBC_BUILD_NOEXECSTACK
2114 bool "Build uClibc with noexecstack marking"
2117 Mark all assembler files as noexecstack, which will mark uClibc
2118 as not requiring an executable stack. (This doesn't prevent other
2119 files you link against from claiming to need an executable stack, it
2120 just won't cause uClibc to request it unnecessarily.)
2122 This is a security thing to make buffer overflows harder to exploit.
2123 By itself, it's kind of useless, as Linus Torvalds explained in 1998:
2124 http://old.lwn.net/1998/0806/a/linus-noexec.html
2126 It only actually provides any security when combined with address
2127 space randomization, explained here: http://lwn.net/Articles/121845/
2129 Address space randomization is on by default in current linux
2130 kernels (although it can be disabled using the option
2133 You should probably say Y.
2137 menu "Development/debugging options"
2139 config CROSS_COMPILER_PREFIX
2140 string "Cross-compiling toolchain prefix"
2143 The prefix used to execute your cross-compiling toolchain. For
2144 example, if you run 'arm-linux-uclibc-gcc' to compile something,
2145 then enter 'arm-linux-uclibc-' here.
2147 config UCLIBC_EXTRA_CFLAGS
2148 string "Extra CFLAGS"
2151 Add any additional CFLAGS to be used to build uClibc.
2154 bool "Enable debugging symbols"
2155 select EXTRA_WARNINGS
2157 Say Y here if you wish to compile uClibc with debugging symbols.
2158 This will allow you to use a debugger to examine uClibc internals
2159 while applications are running. This increases the size of the
2160 library considerably and should only be used when doing development.
2161 If you are doing development and want to debug uClibc, answer Y.
2163 Otherwise, answer N.
2166 bool "Build pthread with debugging output"
2167 depends on UCLIBC_HAS_THREADS && UCLIBC_HAS_LINUXTHREADS
2169 Enable debug output in libpthread. This is only useful when doing
2170 development in libpthread itself.
2172 Otherwise, answer N.
2175 bool "Strip libraries and executables"
2179 Say Y here if you do wish to strip all uClibc libraries and
2180 executables. No stripping increases the size of the binaries
2181 considerably, but makes it possible to debug uClibc libraries.
2182 Most people will answer Y.
2185 bool "Build with run-time assertion testing"
2187 Say Y here to include runtime assertion tests.
2188 This enables runtime assertion testing in some code, which can
2189 increase the size of the library and incur runtime overhead.
2190 If you say N, then this testing will be disabled.
2192 config SUPPORT_LD_DEBUG
2193 bool "Build the shared library loader with debugging support"
2194 depends on HAVE_SHARED
2196 Answer Y here to enable all the extra code needed to debug the uClibc
2197 native shared library loader. The level of debugging noise that is
2198 generated depends on the LD_DEBUG environment variable... Just set
2199 LD_DEBUG to something like: 'LD_DEBUG=token1,token2,.. prog' to
2200 debug your application. Diagnostic messages will then be printed to
2203 For now these debugging tokens are available:
2204 detail provide more information for some options
2205 move display copy processing
2206 symbols display symbol table processing
2207 reloc display relocation processing; detail shows the
2209 nofixups never fixes up jump relocations
2210 bindings displays the resolve processing (function calls);
2211 detail shows the relocation patch
2212 all Enable everything!
2214 The additional environment variable:
2215 LD_DEBUG_OUTPUT=file
2216 redirects the diagnostics to an output file created using
2217 the specified name and the process id as a suffix.
2219 An excellent start is simply:
2220 $ LD_DEBUG=binding,move,symbols,reloc,detail ./appname
2221 or to log everything to a file named 'logfile', try this
2222 $ LD_DEBUG=all LD_DEBUG_OUTPUT=logfile ./appname
2224 If you are doing development and want to debug uClibc's shared library
2225 loader, answer Y. Mere mortals answer N.
2227 config SUPPORT_LD_DEBUG_EARLY
2228 bool "Build the shared library loader with early debugging support"
2229 depends on HAVE_SHARED
2231 Answer Y here to if you find the uClibc shared library loader is
2232 crashing or otherwise not working very early on. This is typical
2233 only when starting a new port when you haven't figured out how to
2234 properly get the values for argc, argv, environ, etc. This method
2235 allows a degree of visibility into the very early shared library
2236 loader initialization process. If you are doing development and want
2237 to debug the uClibc shared library loader early initialization,
2238 answer Y. Mere mortals answer N.
2240 config UCLIBC_MALLOC_DEBUGGING
2241 bool "Build malloc with debugging support"
2242 depends on MALLOC || MALLOC_STANDARD
2245 Answer Y here to compile extra debugging support code into malloc.
2246 Malloc debugging output may then be enabled at runtime using the
2247 MALLOC_DEBUG environment variable.
2249 The value of MALLOC_DEBUG should be an integer, which is interpreted
2250 as a bitmask with the following bits:
2251 1 - do extra consistency checking
2252 2 - output messages for malloc/free calls and OS
2254 4 - output messages for the `MMB' layer
2255 8 - output messages for internal malloc heap manipulation
2258 Because this increases the size of malloc appreciably (due to strings
2259 etc), you should say N unless you need to debug a malloc problem.
2261 config UCLIBC_HAS_BACKTRACE
2262 bool "Add support for application self-debugging"
2263 depends on HAVE_SHARED
2265 Answer Y here to compile support for application self-debugging that
2266 provides the following new functions:
2267 backtrace, backtrace_symbols, backtrace_symbols_fd
2269 The backtrace functionality is currently supported on some platforms, and it
2270 based on dwarf2 informations to properly work, so any application that
2271 want to use backtrace needs to be built with -fexceptions flag.
2273 The symbol names may be unavailable without the use of special linker
2274 options. For systems using the GNU linker, it is necessary to use the
2275 -rdynamic linker option too. Note that names of "static" functions are not
2276 exposed, and won't be available in the backtrace.
2279 string "Compiler Warnings"
2282 Set this to the set of compiler warnings you wish to see while compiling.
2284 config EXTRA_WARNINGS
2285 bool "Enable extra annoying warnings"
2287 If you wish to build with extra warnings enabled, say Y here.