| blob | fc6669b892603c3b6aab257486cf68013e7b0880 |
1 #
2 # For a description of the syntax of this configuration file,
3 # see extra/config/Kconfig-language.txt
4 #
6 mainmenu "uClibc-ng $VERSION C Library Configuration"
8 config DESIRED_TARGET_ARCH
9 string
10 option env="ARCH"
12 config VERSION
13 string
14 option env="VERSION"
16 choice
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"
42 help
43 The architecture of your target.
45 config TARGET_alpha
46 bool "alpha"
48 config TARGET_arc
49 bool "arc"
51 config TARGET_arm
52 bool "arm"
54 config TARGET_avr32
55 bool "avr32"
57 config TARGET_bfin
58 bool "bfin"
60 # someone could sync this tree:
61 # http://linux-c6x.org/git/?p=uClibc.git;a=summary
62 config TARGET_c6x
63 bool "c6x"
65 config TARGET_cris
66 bool "cris"
68 config TARGET_frv
69 bool "frv"
71 config TARGET_h8300
72 bool "h8300"
74 config TARGET_hppa
75 bool "hppa"
77 config TARGET_i386
78 bool "i386"
80 config TARGET_ia64
81 bool "ia64"
83 config TARGET_lm32
84 bool "lm32"
86 config TARGET_m68k
87 bool "m68k"
89 config TARGET_metag
90 bool "metag"
92 config TARGET_microblaze
93 bool "microblaze"
95 config TARGET_mips
96 bool "mips"
98 config TARGET_nds32
99 bool "nds32"
101 config TARGET_nios2
102 bool "nios2"
104 config TARGET_or1k
105 bool "or1k"
107 config TARGET_powerpc
108 bool "powerpc"
110 config TARGET_sh
111 bool "superh"
113 config TARGET_sparc
114 bool "sparc"
116 config TARGET_x86_64
117 bool "x86_64"
119 config TARGET_xtensa
120 bool "xtensa"
122 endchoice
125 menu "Target Architecture Features and Options"
127 if TARGET_alpha
128 source "extra/Configs/Config.alpha"
129 endif
131 if TARGET_arm
132 source "extra/Configs/Config.arm"
133 endif
135 if TARGET_avr32
136 source "extra/Configs/Config.avr32"
137 endif
139 if TARGET_bfin
140 source "extra/Configs/Config.bfin"
141 endif
143 if TARGET_cris
144 source "extra/Configs/Config.cris"
145 endif
147 if TARGET_frv
148 source "extra/Configs/Config.frv"
149 endif
151 if TARGET_h8300
152 source "extra/Configs/Config.h8300"
153 endif
155 if TARGET_hppa
156 source "extra/Configs/Config.hppa"
157 endif
159 if TARGET_i386
160 source "extra/Configs/Config.i386"
161 endif
163 if TARGET_ia64
164 source "extra/Configs/Config.ia64"
165 endif
167 if TARGET_lm32
168 source "extra/Configs/Config.lm32"
169 endif
171 if TARGET_m68k
172 source "extra/Configs/Config.m68k"
173 endif
175 if TARGET_metag
176 source "extra/Configs/Config.metag"
177 endif
179 if TARGET_nds32
180 source "extra/Configs/Config.nds32"
181 endif
183 if TARGET_nios2
184 source "extra/Configs/Config.nios2"
185 endif
187 if TARGET_microblaze
188 source "extra/Configs/Config.microblaze"
189 endif
191 if TARGET_mips
192 source "extra/Configs/Config.mips"
193 endif
195 if TARGET_or1k
196 source "extra/Configs/Config.or1k"
197 endif
199 if TARGET_powerpc
200 source "extra/Configs/Config.powerpc"
201 endif
203 if TARGET_sh
204 source "extra/Configs/Config.sh"
205 endif
207 if TARGET_sparc
208 source "extra/Configs/Config.sparc"
209 endif
211 if TARGET_x86_64
212 source "extra/Configs/Config.x86_64"
213 endif
215 if TARGET_xtensa
216 source "extra/Configs/Config.xtensa"
217 endif
219 if TARGET_c6x
220 source "extra/Configs/Config.c6x"
221 endif
223 if TARGET_arc
224 source "extra/Configs/Config.arc"
225 endif
227 config TARGET_SUBARCH
228 string
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
238 default ""
240 source "extra/Configs/Config.in.arch"
242 endmenu
244 menu "General Library Settings"
246 config HAVE_NO_PIC
247 bool
249 config DOPIC
250 bool "Generate only Position Independent Code (PIC)"
251 default y
252 depends on !HAVE_NO_PIC
253 help
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
258 bool
260 config ARCH_HAS_NO_LDSO
261 bool
262 select ARCH_HAS_NO_SHARED
264 config ARCH_HAS_UCONTEXT
265 bool
267 config HAVE_SHARED
268 bool "Enable shared libraries"
269 depends on !ARCH_HAS_NO_SHARED
270 default y
271 help
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,
274 then answer N.
276 config FORCE_SHAREABLE_TEXT_SEGMENTS
277 bool "Only load shared libraries which can share their text segment"
278 depends on HAVE_SHARED
279 select DOPIC
280 help
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
294 default y
295 help
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
306 default y
307 help
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
316 default y
317 help
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
328 help
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
331 the program.
333 config LDSO_BASE_FILENAME
334 string "Shared library loader naming prefix"
335 depends on HAVE_SHARED && (LDSO_CACHE_SUPPORT || LDSO_PRELOAD_FILE_SUPPORT)
336 default "ld.so"
337 help
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
348 binutils' ld !
350 config LDSO_STANDALONE_SUPPORT
351 bool "Dynamic linker stand-alone mode support"
352 depends on HAVE_SHARED
353 help
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
370 help
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
374 binaries at runtime.
376 config UCLIBC_STATIC_LDCONFIG
377 bool "Link ldconfig statically"
378 depends on HAVE_SHARED
379 default y
380 help
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.
388 config LDSO_RUNPATH
389 bool "Enable ELF RUNPATH tag support"
390 depends on HAVE_SHARED
391 default y if LDSO_CACHE_SUPPORT
392 help
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
404 default n
405 help
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
413 default y
414 help
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
420 default y
421 help
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
434 default y
435 help
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
445 help
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
454 bool
455 default y
456 help
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
468 answer N.
470 config LDSO_GNU_HASH_SUPPORT
471 bool "Enable GNU hash style support"
472 depends on HAVE_SHARED
473 help
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
478 compatible.
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
485 choice
486 prompt "Thread support"
487 default HAS_NO_THREADS
488 help
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
495 bool "none"
496 help
497 Disable thread support.
499 config UCLIBC_HAS_LINUXTHREADS
500 bool "Linuxthreads"
501 # linuxthreads need nanosleep()
502 select UCLIBC_HAS_REALTIME
503 depends on !TARGET_arc && \
504 !TARGET_arm && \
505 !TARGET_i386 && \
506 !TARGET_metag && \
507 !TARGET_mips && \
508 !TARGET_powerpc && \
509 !TARGET_sparc && \
510 !TARGET_x86_64 && \
511 !TARGET_xtensa || \
512 !ARCH_USE_MMU
513 help
514 If you want to compile uClibc with Linuxthreads support, then answer Y.
516 config UCLIBC_HAS_THREADS_NATIVE
517 bool "Native POSIX Threading (NPTL)"
518 select UCLIBC_HAS_TLS
519 select UCLIBC_HAS_STDIO_FUTEXES
520 select UCLIBC_HAS_REALTIME
521 # i386 has no lowlevellock support (yet) as opposed to i486 onward
522 depends on !CONFIG_386 && \
523 !TARGET_alpha && \
524 !TARGET_avr32 && \
525 !TARGET_bfin && \
526 !TARGET_c6x && \
527 !TARGET_cris && \
528 !TARGET_frv && \
529 !TARGET_h8300 && \
530 !TARGET_hppa && \
531 !TARGET_ia64 && \
532 !TARGET_m68k && \
533 !TARGET_microblaze && \
534 !TARGET_nds32 && \
535 !TARGET_nios2 && \
536 !TARGET_or1k && \
537 ARCH_USE_MMU
538 help
539 If you want to compile uClibc with NPTL support, then answer Y.
541 endchoice
543 config UCLIBC_HAS_THREADS
544 def_bool y if !HAS_NO_THREADS
546 config UCLIBC_HAS_TLS
547 bool "Thread-Local Storage"
548 depends on UCLIBC_HAS_THREADS_NATIVE
549 help
550 If you want to enable TLS support then answer Y.
551 This is fast an efficient way to store per-thread local data
552 which is not on stack. It needs __thread support enabled in
553 gcc.
555 config PTHREADS_DEBUG_SUPPORT
556 bool "Build pthreads debugging support"
557 depends on UCLIBC_HAS_THREADS
558 help
559 Say Y here if you wish to be able to debug applications that use
560 uClibc's pthreads library. By enabling this option, a library
561 named libthread_db will be built. This library will be dlopen()'d
562 by gdb and will allow gdb to debug the threads in your application.
564 IMPORTANT NOTE! Because gdb must dlopen() the libthread_db library,
565 you must compile gdb with uClibc in order for pthread debugging to
566 work properly.
568 If you are doing development and want to debug applications using
569 uClibc's pthread library, answer Y. Otherwise, answer N.
572 config UCLIBC_HAS_SYSLOG
573 bool "Syslog support"
574 default y
575 depends on UCLIBC_HAS_NETWORK_SUPPORT
576 select UCLIBC_HAS_SOCKET
577 help
578 Support sending messages to the system logger.
579 This requires socket-support.
581 config UCLIBC_HAS_LFS
582 bool "Large File Support"
583 default y
584 help
585 If you wish to build uClibc with support for accessing large files
586 (i.e. files greater then 2 GiB) then answer Y. Do not enable this
587 if you are using an older Linux kernel (2.0.x) that lacks large file
588 support. Enabling this option will increase the size of uClibc.
590 choice
591 prompt "Malloc Implementation"
592 default MALLOC if ! ARCH_USE_MMU
593 default MALLOC_STANDARD if ARCH_USE_MMU
595 config MALLOC
596 bool "malloc"
597 help
598 "malloc" use mmap for all allocations and so works very well on
599 MMU-less systems that do not support the brk() system call. It is
600 pretty smart about reusing already allocated memory, and minimizing
601 memory wastage.
602 This is the default for uClinux MMU-less systems.
604 config MALLOC_SIMPLE
605 bool "malloc-simple"
606 help
607 "malloc-simple" is trivially simple and slow as molasses. It
608 was written from scratch for uClibc, and is the simplest possible
609 (and therefore smallest) malloc implementation.
611 This uses only the mmap() system call to allocate and free memory,
612 and does not use the brk() system call at all, making it a fine
613 choice for MMU-less systems with very limited memory. It's 100%
614 standards compliant, thread safe, very small, and releases freed
615 memory back to the OS immediately rather than keeping it in the
616 process's heap for reallocation. It is also VERY SLOW.
618 config MALLOC_STANDARD
619 bool "malloc-standard"
620 depends on ARCH_USE_MMU
621 help
622 "malloc-standard" is derived from the public domain dlmalloc
623 implementation by Doug Lea. It is quite fast, and is pretty smart
624 about reusing already allocated memory, and minimizing memory
625 wastage. This uses brk() for small allocations, while using mmap()
626 for larger allocations. This is the default malloc implementation
627 for uClibc.
629 If unsure, answer "malloc-standard".
631 endchoice
633 config MALLOC_GLIBC_COMPAT
634 bool "Malloc returns live pointer for malloc(0)"
635 help
636 The behavior of malloc(0) is listed as implementation-defined by
637 SuSv3. Glibc returns a valid pointer to something, while uClibc
638 normally returns NULL. I personally feel glibc's behavior is
639 not particularly safe, and allows buggy applications to hide very
640 serious problems.
642 When this option is enabled, uClibc will act just like glibc, and
643 return a live pointer when someone calls malloc(0). This pointer
644 provides a malloc'ed area with a size of 1 byte. This feature is
645 mostly useful when dealing with applications using autoconf's broken
646 AC_FUNC_MALLOC macro (which redefines malloc as rpl_malloc if it
647 does not detect glibc style returning-a-valid-pointer-for-malloc(0)
648 behavior). Most people can safely answer N.
650 config UCLIBC_HAS_OBSTACK
651 bool "Obstack Support (gnu extension)"
652 help
653 When this option is enabled, uClibc will provide support for obstacks.
654 An obstack is a structure in which memory can be dynamically allocated
655 as a 'stack of objects'. Many programs need this GNU extention and
656 you should say Y if you are using any. Otherwise, say N to save some
657 space.
659 config UCLIBC_DYNAMIC_ATEXIT
660 bool "Dynamic atexit() Support"
661 default y
662 help
663 When this option is enabled, uClibc will support an infinite number,
664 of atexit() and on_exit() functions, limited only by your available
665 memory. This can be important when uClibc is used with C++, since
666 global destructors are implemented via atexit(), and it is quite
667 possible to exceed the default number when this option is disabled.
668 Enabling this option adds a few bytes, and more significantly makes
669 atexit and on_exit depend on malloc, which can be bad when compiling
670 static executables.
672 Unless you use uClibc with C++, you should probably answer N.
674 config COMPAT_ATEXIT
675 bool "Old (visible) atexit Support"
676 help
677 Enable this option if you want to update from 0.9.28 to git/0.9.29,
678 else you will be missing atexit() until you rebuild all apps.
680 config UCLIBC_HAS_UTMPX
681 bool "utmpx based support for tracking login/logouts to/from the system"
682 help
683 Answer y to enable support for accessing user accounting database.
684 It can be used to track all login/logout to the system.
686 config UCLIBC_HAS_UTMP
687 bool "utmp support (XPG2 compat, SVr4 compat)"
688 depends on UCLIBC_HAS_UTMPX
689 help
690 Answer y to enable legacy SVID support for accessing
691 user accounting database:
692 getutent(), getutid(), getutline(), pututline(),
693 setutent(), endutent(), utmpname() in utmp.h
694 It can be used to track all login/logout to the system.
696 If unsure, answer N and use corresponding POSIX functions
697 from utmpx.h
699 config UCLIBC_SUSV2_LEGACY
700 bool "Enable SuSv2 LEGACY functions"
701 help
702 Enable this option if you want to have SuSv2 LEGACY functions
703 Currently applies to:
705 valloc
707 WARNING! ABI incompatibility.
709 config UCLIBC_SUSV3_LEGACY
710 bool "Enable SuSv3 LEGACY functions"
711 #vfork,
712 # h_errno
713 # gethostbyaddr
714 # gethostbyname
715 help
716 Enable this option if you want to have SuSv3 LEGACY functions
717 in the library, else they are replaced by SuSv3 proposed macros.
718 Currently applies to:
720 bcmp, bcopy, bzero, index, rindex, ftime,
721 bsd_signal, (ecvt), (fcvt), gcvt, (getcontext),
722 (getwd), (makecontext),
723 mktemp, (pthread_attr_getstackaddr), (pthread_attr_setstackaddr),
724 scalb, (setcontext), (swapcontext), ualarm, usleep,
725 wcswcs.
727 WARNING! ABI incompatibility.
729 config UCLIBC_HAS_CONTEXT_FUNCS
730 bool "Use obsolescent context control functions"
731 depends on UCLIBC_SUSV3_LEGACY && ARCH_HAS_UCONTEXT
732 help
733 Add into library the SuSv3 obsolescent functions used for context
734 control. The setcontext family allows the implementation in C of
735 advanced control flow patterns such as iterators, fibers, and
736 coroutines. They may be viewed as an advanced version of
737 setjmp/longjmp; whereas the latter allows only a single non-local jump
738 up the stack, setcontext allows the creation of multiple cooperative
739 threads of control, each with its own stack.
740 These functions are: setcontext, getcontext, makecontext, swapcontext.
742 config UCLIBC_SUSV3_LEGACY_MACROS
743 bool "Enable SuSv3 LEGACY macros"
744 help
745 Enable this option if you want to have SuSv3 LEGACY macros.
746 Currently applies to bcopy/bzero/bcmp/index/rindex et al.
747 WARNING! ABI incompatibility.
749 config UCLIBC_SUSV4_LEGACY
750 bool "Enable SuSv4 LEGACY or obsolescent functions"
751 help
752 Enable this option if you want to have SuSv4 LEGACY functions
753 and macros in the library.
754 Currently applies to:
756 - XSI functions:
757 _longjmp, _setjmp, _tolower, _toupper, ftw, getitimer,
758 gettimeofday, isascii, pthread_getconcurrency,
759 pthread_setconcurrency, setitimer, setpgrp, sighold,
760 sigignore, sigpause, sigrelse, sigset, siginterrupt,
761 tempnam, toascii, ulimit.
763 - Base functions:
764 asctime, asctime_r, ctime, ctime_r, gets, rand_r,
765 tmpnam, utime.
767 WARNING! ABI incompatibility.
769 config UCLIBC_STRICT_HEADERS
770 bool "Hide structures and constants for unsupported features"
771 help
772 Hide structures and constants in headers that should not be used,
773 because the respective feature is disabled.
775 WARNING! enabling this option requires to patch many faulty apps,
776 since they make (wrongly) use of these structures/constants,
777 although the feature was disabled.
779 config UCLIBC_HAS_STUBS
780 bool "Provide stubs for unavailable functionality"
781 help
782 With this option uClibc provides non-functional stubs for
783 functions which are impossible to implement on the target
784 architecture. Otherwise, such functions are simply omitted.
786 config UCLIBC_HAS_SHADOW
787 bool "Shadow Password Support"
788 default y
789 help
790 Answer N if you do not need shadow password support.
791 Most people will answer Y.
793 config UCLIBC_HAS_PROGRAM_INVOCATION_NAME
794 bool "Support for program_invocation_name"
795 help
796 Support for the GNU-specific program_invocation_name and
797 program_invocation_short_name strings. Some GNU packages
798 (like tar and coreutils) utilize these for extra useful
799 output, but in general are not required.
801 At startup, these external strings are automatically set
802 up based on the value of ARGV[0].
804 If unsure, just answer N.
806 config UCLIBC_HAS___PROGNAME
807 bool "Support for __progname"
808 default y
809 help
810 Some packages (like openssh) like to peek into internal libc
811 symbols to make their output a bit more user friendly.
813 At startup, __progname is automatically set up based on the
814 value of ARGV[0].
816 If unsure, just answer N.
818 config UCLIBC_HAS_PTY
819 bool "Support for pseudo-terminals"
820 default y
821 help
822 This enables support for pseudo-terminals (see man 4 pts
823 and man 7 pty).
825 If unsure, just answer Y.
827 config ASSUME_DEVPTS
828 bool "Assume that /dev/pts is a devpts or devfs file system"
829 default y
830 depends on UCLIBC_HAS_PTY
831 help
832 Enable this if /dev/pts is on a devpts or devfs filesystem. Both
833 these filesystems automatically manage permissions on the /dev/pts
834 devices. You may need to mount your devpts or devfs filesystem on
835 /dev/pts for this to work.
837 Most people should answer Y.
839 config UNIX98PTY_ONLY
840 bool "Support only Unix 98 PTYs"
841 default y
842 depends on UCLIBC_HAS_PTY
843 help
844 If you want to support only Unix 98 PTYs enable this. Some older
845 applications may need this disabled and will thus use legacy BSD
846 style PTY handling which is more complex and also bigger than
847 Unix 98 PTY handling.
849 For most current programs, you can generally answer Y.
851 if UNIX98PTY_ONLY
852 config UCLIBC_HAS_GETPT
853 bool "Support getpt() (glibc-compat)"
854 depends on UCLIBC_HAS_PTY
855 help
856 Some packages may need getpt().
857 All of those are non-standard and can be considered
858 GNU/libc compatibility.
859 Either use posix_openpt() or just open /dev/ptmx yourself.
861 If unsure, just say N.
862 endif
864 if !UNIX98PTY_ONLY
865 # Have to use __libc_ptyname{1,2}[] and related bloat
866 config UCLIBC_HAS_GETPT
867 def_bool y
868 endif
870 config UCLIBC_HAS_LIBUTIL
871 bool "Provide libutil library and functions"
872 depends on UCLIBC_HAS_PTY
873 help
874 Provide a libutil library.
875 This non-standard conforming library provides the following
876 utility functions:
878 forkpty(): combines openpty(), fork(2), and login_tty() to
879 create a new process operating in a pseudo-terminal.
880 login(): write utmp and wtmp entries
881 login_tty(): prepares for a login on the tty fd by creating a
882 new session, making fd the controlling terminal for
883 the calling process, setting fd to be the standard
884 input, output, and error streams of the current
885 process, and closing fd.
886 logout(): write utmp and wtmp entries
887 logwtmp(): constructs a utmp structure and calls updwtmp() to
888 append the structure to the utmp file.
889 openpty(): finds an available pseudo-terminal and returns
890 file descriptors for the master and slave
892 This library adds about 3k-4k to your system.
894 config UCLIBC_HAS_TM_EXTENSIONS
895 bool "Support 'struct tm' timezone extension fields"
896 default y
897 help
898 Enabling this option adds fields to 'struct tm' in time.h for
899 tracking the number of seconds east of UTC, and an abbreviation for
900 the current timezone. These fields are not specified by the SuSv3
901 standard, but they are commonly used in both GNU and BSD application
902 code.
904 To strictly follow the SuSv3 standard, leave this disabled.
905 Most people will probably want to answer Y.
907 config UCLIBC_HAS_TZ_CACHING
908 bool "Enable caching of the last valid timezone 'TZ' string"
909 default y
910 help
911 Answer Y to enable caching of the last valid 'TZ' string describing
912 the timezone setting. This allows a quick string compare to avoid
913 repeated parsing of unchanged 'TZ' strings when tzset() is called.
915 Most people will answer Y.
917 config UCLIBC_HAS_TZ_FILE
918 bool "Enable '/etc/TZ' file support to set a default timezone (uClibc-specific)"
919 default y
920 help
921 Answer Y to enable the setting of a default timezone for uClibc.
923 Ordinarily, uClibc gets the timezone information exclusively from the
924 'TZ' environment variable. In particular, there is no support for
925 the zoneinfo directory tree or the /etc/timezone file used by glibc.
927 With this option enabled, uClibc will use the value stored in the
928 file '/etc/TZ' (default path) to obtain timezone information if the
929 'TZ' environment variable is missing or has an invalid value. The
930 file consists of a single line (newline required) of text describing
931 the timezone in the format specified for the TZ environment variable.
933 Doing 'echo CST6CDT > /etc/TZ' is enough to create a valid file.
934 See
935 http://www.opengroup.org/onlinepubs/007904975/basedefs/xbd_chap08.html
936 for details on valid settings of 'TZ'.
938 Most people will answer Y.
940 config UCLIBC_HAS_TZ_FILE_READ_MANY
941 bool "Repeatedly read the '/etc/TZ' file"
942 depends on UCLIBC_HAS_TZ_FILE
943 default y
944 help
945 Answer Y to enable repeated reading of the '/etc/TZ' file even after
946 a valid value has been read. This incurs the overhead of an
947 open/read/close for each tzset() call (explicit or implied). However,
948 setting this will allow applications to update their timezone
949 information if the contents of the file change.
951 Most people will answer Y.
953 config UCLIBC_TZ_FILE_PATH
954 string "Path to the 'TZ' file for setting the global timezone"
955 depends on UCLIBC_HAS_TZ_FILE
956 default "/etc/TZ"
957 help
958 This is the path to the 'TZ' file.
960 Most people will use the default of '/etc/TZ'.
962 config UCLIBC_FALLBACK_TO_ETC_LOCALTIME
963 bool "Use /etc/localtime as a fallback"
964 depends on UCLIBC_HAS_TZ_FILE
965 default y
966 help
967 Answer Y to try to use /etc/localtime file.
968 On glibc systems this file (if it is in TZif2 format)
969 contains timezone string at the end.
971 Most people will answer Y.
973 endmenu
975 menu "Advanced Library Settings"
977 config UCLIBC_PWD_BUFFER_SIZE
978 int "Buffer size for getpwnam() and friends"
979 default 256
980 range 12 1024
981 help
982 This sets the value of the buffer size for getpwnam() and friends.
983 By default, this is 256. (For reference, glibc uses 1024).
984 The value can be found using sysconf() with the _SC_GETPW_R_SIZE_MAX
985 parameter.
987 config UCLIBC_GRP_BUFFER_SIZE
988 int "Buffer size for getgrnam() and friends"
989 default 256
990 range 12 1024
991 help
992 This sets the value of the buffer size for getgrnam() and friends.
993 By default, this is 256. (For reference, glibc uses 1024).
994 The value can be found using sysconf() with the _SC_GETGR_R_SIZE_MAX
995 parameter.
997 comment "Support various families of functions"
999 config UCLIBC_LINUX_MODULE_26
1000 bool "Linux kernel module functions (2.6)"
1001 default y
1002 help
1003 delete_module, init_module
1004 are used in linux for loadable kernel modules.
1006 Say N if you do not use kernel modules.
1008 config UCLIBC_LINUX_MODULE_24
1009 bool "Linux kernel module functions (<2.6)"
1010 depends on !TARGET_bfin && !TARGET_c6x
1011 help
1012 create_module, query_module
1013 are used in linux (prior to 2.6) for loadable kernel modules.
1015 Say N if you do not use kernel modules, or you only support
1016 Linux 2.6+.
1018 config UCLIBC_LINUX_SPECIFIC
1019 bool "Linux specific functions"
1020 default y
1021 help
1022 accept4(), bdflush(),
1023 capget(), capset(), eventfd(), fallocate(),
1024 fstatfs(), getrandom(), inotify_*(), ioperm(), iopl(),
1025 madvise(), modify_ldt(), pipe2(), personality(),
1026 prctl()/arch_prctl(), pivot_root(), modify_ldt(),
1027 ppoll(), readahead(), reboot(), remap_file_pages(),
1028 sched_getaffinity(), sched_setaffinity(), sendfile(),
1029 setfsgid(), setfsuid(), setresgid(), setresuid(),
1030 splice(), vmsplice(), tee(), signalfd(), statfs(),
1031 swapoff(), swapon(), sync_file_range(), syncfs(),
1032 _sysctl(), sysinfo(), timerfd_*(), vhangup(), umount(),
1033 umount2()
1035 config UCLIBC_HAS_GNU_ERROR
1036 bool "Support GNU extensions for error-reporting"
1037 default y
1038 help
1039 Support for the GNU-specific error(), error_at_line(),
1040 void (* error_print_progname)(), error_message_count
1041 functions and variables. Some GNU packages
1042 utilize these for extra useful output, but in general
1043 are not required.
1045 If unsure, just answer N.
1047 config UCLIBC_BSD_SPECIFIC
1048 bool "BSD specific functions"
1049 default y
1050 help
1051 mincore(), getdomainname(), setdomainname()
1053 If unsure, say N.
1055 config UCLIBC_HAS_BSD_ERR
1056 bool "BSD err functions"
1057 default y
1058 help
1059 These functions are non-standard BSD extensions.
1060 err(), errx(), warn(), warnx(), verr(), verrx(), vwarn(), vwarnx()
1062 If unsure, say N.
1064 config UCLIBC_HAS_OBSOLETE_BSD_SIGNAL
1065 bool "BSD obsolete signal functions"
1066 help
1067 These functions are provided as a compatibility interface for
1068 programs that make use of the historical System V signal API.
1069 This API is obsolete:
1070 new applications should use the POSIX signal API (sigaction(2),
1071 sigprocmask(2), etc.).
1072 Affected functions:
1074 sigset(), sighold(), sigrelse(), sigignore()
1076 If unsure, say N.
1078 config UCLIBC_HAS_OBSOLETE_SYSV_SIGNAL
1079 bool "SYSV obsolete signal functions"
1080 help
1081 Use of sysv_signal() should be avoided; use sigaction(2) instead.
1083 If unsure, say N.
1085 config UCLIBC_NTP_LEGACY
1086 bool "ntp_*() aliases"
1087 help
1088 Provide legacy aliases for ntp functions:
1089 ntp_adjtime(), ntp_gettime()
1091 It is safe to say N here.
1093 config UCLIBC_SV4_DEPRECATED
1094 bool "Enable SVr4 deprecated functions"
1095 help
1096 These functions are DEPRECATED in System V release 4.
1097 Say N unless you desparately need one of the functions below:
1099 ustat() [use statfs(2) in your code instead]
1101 config UCLIBC_HAS_REALTIME
1102 bool "Realtime-related family of SUSv functions"
1103 default y
1104 help
1105 These functions are part of the Timers option and need not
1106 be available on all implementations.
1107 Includes AIO, message-queue, scheduler, semaphore functions:
1109 aio.h
1110 mqueue.h
1111 sched.h
1112 semaphore.h
1114 aio_cancel()
1115 aio_error()
1116 aio_fsync()
1117 aio_read()
1118 lio_listio()
1119 aio_return()
1120 aio_suspend()
1121 aio_write()
1122 clock_getres(), clock_gettime(), clock_settime()
1123 fdatasync()
1124 mlockall(), munlockall()
1125 mlock(), munlock()
1126 mq_close()
1127 mq_getattr()
1128 mq_notify()
1129 mq_open()
1130 mq_receive()
1131 mq_send()
1132 mq_setattr()
1133 mq_unlink()
1134 nanosleep()
1135 sched_getparam()
1136 sched_get_priority_max(), sched_get_priority_min()
1137 sched_getscheduler()
1138 sched_rr_get_interval()
1139 sched_setparam()
1140 sched_setscheduler()
1141 sem_close()
1142 sem_destroy()
1143 sem_getvalue()
1144 sem_init()
1145 sem_open()
1146 sem_post()
1147 sem_trywait(), sem_wait()
1148 sem_unlink()
1149 sigqueue()
1150 sigtimedwait(), sigwaitinfo()
1151 timer_create()
1152 timer_delete()
1153 timer_getoverrun(), timer_gettime(), timer_settime()
1155 config UCLIBC_HAS_ADVANCED_REALTIME
1156 bool "Advanced realtime-related family of SUSv functions"
1157 default y
1158 depends on UCLIBC_HAS_REALTIME
1159 help
1160 These functions are part of the Timers option and need not
1161 be available on all implementations.
1163 clock_getcpuclockid()
1164 clock_nanosleep()
1165 mq_timedreceive()
1166 mq_timedsend()
1167 posix_fadvise()
1168 posix_fallocate()
1169 posix_madvise()
1170 posix_memalign()
1171 posix_mem_offset()
1172 posix_spawnattr_destroy(), posix_spawnattr_init()
1173 posix_spawnattr_getflags(), posix_spawnattr_setflags()
1174 posix_spawnattr_getpgroup(), posix_spawnattr_setpgroup()
1175 posix_spawnattr_getschedparam(), posix_spawnattr_setschedparam()
1176 posix_spawnattr_getschedpolicy(), posix_spawnattr_setschedpolicy()
1177 posix_spawnattr_getsigdefault(), posix_spawnattr_setsigdefault()
1178 posix_spawnattr_getsigmask(), posix_spawnattr_setsigmask()
1179 posix_spawn_file_actions_addclose()
1180 posix_spawn_file_actions_adddup2()
1181 posix_spawn_file_actions_addopen()
1182 posix_spawn_file_actions_destroy()
1183 posix_spawn_file_actions_init()
1184 posix_spawn()
1185 posix_spawnp()
1186 posix_typed_mem_get_info()
1187 pthread_mutex_timedlock()
1188 sem_timedwait()
1190 #config UCLIBC_HAS_TERMIOS
1191 # bool "termios functions"
1192 # default y
1193 # help
1194 # Get and set terminal attributes, line control, get and set baud
1195 # rate.
1196 # termios(), tcgetattr(), tcsetattr(), tcsendbreak(), tcdrain(),
1197 # tcflush(), tcflow(), cfmakeraw(), cfgetospeed(), cfgetispeed(),
1198 # cfsetispeed(), cfsetospeed(), cfsetspeed()
1199 #
1200 # If unsure, say Y.
1202 config UCLIBC_HAS_EPOLL
1203 bool "epoll"
1204 default y
1205 help
1206 epoll_create(), epoll_ctl(), epoll_wait() functions.
1208 config UCLIBC_HAS_XATTR
1209 bool "Extended Attributes"
1210 default y
1211 help
1212 Extended Attributes support.
1214 setxattr()
1215 lsetxattr()
1216 fsetxattr()
1217 getxattr()
1218 lgetxattr()
1219 fgetxattr()
1220 listxattr()
1221 llistxattr()
1222 flistxattr()
1223 removexattr()
1224 lremovexattr()
1225 fremovexattr()
1227 Say N unless you need support for extended attributes and the
1228 filesystems do actually support them.
1230 config UCLIBC_HAS_PROFILING
1231 bool "Profiling support"
1232 default y
1233 help
1234 gcc's -finstrument-functions needs these.
1236 Most people can safely answer N.
1238 config UCLIBC_HAS_CRYPT_IMPL
1239 bool "libcrypt support"
1240 default y
1241 help
1242 libcrypt contains crypt(), setkey() and encrypt()
1244 config UCLIBC_HAS_SHA256_CRYPT_IMPL
1245 bool "libcrypt SHA256 support"
1246 depends on UCLIBC_HAS_CRYPT_IMPL
1247 help
1248 This adds support for SHA256 password hashing via the crypt() function.
1249 Say N here if you do not need SHA256 crypt support.
1251 config UCLIBC_HAS_SHA512_CRYPT_IMPL
1252 bool "libcrypt SHA512 support"
1253 depends on UCLIBC_HAS_CRYPT_IMPL
1254 help
1255 This adds support for SHA512 password hashing via the crypt() function.
1256 Say N here if you do not need SHA512 crypt support.
1258 config UCLIBC_HAS_CRYPT_STUB
1259 bool "libcrypt stubs"
1260 default y
1261 depends on !UCLIBC_HAS_CRYPT_IMPL
1262 help
1263 Standards mandate that crypt(3) provides a stub if it is unavailable.
1264 If you enable this option then stubs for
1265 crypt(), setkey() and encrypt()
1266 will be provided in a small libcrypt.
1268 config UCLIBC_HAS_CRYPT
1269 def_bool y
1270 depends on UCLIBC_HAS_CRYPT_IMPL || UCLIBC_HAS_CRYPT_STUB
1271 endmenu
1273 menuconfig UCLIBC_HAS_NETWORK_SUPPORT
1274 bool "Networking Support"
1275 default y
1276 help
1277 Say N here if you do not need network support.
1279 if UCLIBC_HAS_NETWORK_SUPPORT
1280 config UCLIBC_HAS_SOCKET
1281 bool "Socket support"
1282 default y
1283 help
1284 If you want to include support for sockets then answer Y.
1286 config UCLIBC_HAS_IPV4
1287 bool "IP version 4 support"
1288 default y
1289 select UCLIBC_HAS_SOCKET
1290 help
1291 If you want to include support for the Internet Protocol
1292 (IP version 4) then answer Y.
1294 Most people will say Y.
1296 config UCLIBC_HAS_IPV6
1297 bool "IP version 6 support"
1298 select UCLIBC_HAS_SOCKET
1299 help
1300 If you want to include support for the next version of the Internet
1301 Protocol (IP version 6) then answer Y.
1303 Most people should answer N.
1305 config UCLIBC_HAS_RPC
1306 bool "Remote Procedure Call (RPC) support"
1307 # RPC+socket-ipvX doesn't currently work.
1308 depends on UCLIBC_HAS_IPV4 || UCLIBC_HAS_IPV6
1309 help
1310 If you want to include RPC support, enable this. RPC is rarely used
1311 for anything except for the NFS filesystem. Unless you plan to use
1312 NFS, you can probably leave this set to N and save some space.
1314 If you need to use NFS then you should answer Y.
1316 config UCLIBC_HAS_FULL_RPC
1317 bool "Full RPC support"
1318 depends on UCLIBC_HAS_RPC
1319 default y if !HAVE_SHARED
1320 help
1321 Normally we enable just enough RPC support for things like rshd and
1322 nfs mounts to work. If you find you need the rest of the RPC stuff,
1323 then enable this option. Most people can safely answer N.
1325 config UCLIBC_HAS_REENTRANT_RPC
1326 bool "Reentrant RPC support"
1327 depends on UCLIBC_HAS_RPC
1328 default y if !HAVE_SHARED
1329 help
1330 Most packages utilize the normal (non-reentrant) RPC functions, but
1331 some (like exportfs from nfs-utils) need these reentrant versions.
1333 Most people can safely answer N.
1335 config UCLIBC_USE_NETLINK
1336 bool "Use netlink to query interfaces"
1337 depends on UCLIBC_HAS_SOCKET
1338 help
1339 In newer versions of Linux (2.4.17+), support was added for querying
1340 network device information via netlink rather than the old style
1341 ioctl's. Most of the time, the older ioctl style is sufficient (and
1342 it is smaller than netlink), but if you find that not all of your
1343 devices are being returned by the if_nameindex() function, you will
1344 have to use the netlink implementation.
1346 Most people can safely answer N.
1348 config UCLIBC_SUPPORT_AI_ADDRCONFIG
1349 bool "Support the AI_ADDRCONFIG flag"
1350 depends on UCLIBC_USE_NETLINK
1351 help
1352 The implementation of AI_ADDRCONFIG is aligned with the glibc
1353 implementation using netlink to query interfaces to find both
1354 ipv4 and ipv6 support. This is only needed if an application uses
1355 the AI_ADDRCONFIG flag.
1357 Most people can safely answer N.
1359 config UCLIBC_HAS_BSD_RES_CLOSE
1360 bool "Support res_close() (bsd-compat)"
1361 help
1362 Answer Y if you desperately want to support BSD compatibility in
1363 the network code.
1365 Most people will say N.
1367 config UCLIBC_HAS_COMPAT_RES_STATE
1368 bool "Use compatible but bloated _res"
1369 default y
1370 help
1371 Answer Y if you build network utilities and they muck with resolver
1372 internals a lot (_res global structure). uclibc does not use most
1373 of _res.XXX fields, and with this option OFF they won't even exist.
1374 Which will make e.g. dig build fail.
1375 Answering N saves around 400 bytes in bss.
1377 config UCLIBC_HAS_EXTRA_COMPAT_RES_STATE
1378 bool "Use extra compatible but extra bloated _res"
1379 help
1380 Answer Y if selecting UCLIBC_HAS_COMPAT_RES_STATE is not enough.
1381 As far as I can say, this should never be needed.
1383 config UCLIBC_HAS_RESOLVER_SUPPORT
1384 bool "DNS resolver functions"
1385 select UCLIBC_HAS_COMPAT_RES_STATE
1386 depends on UCLIBC_HAS_IPV4 || UCLIBC_HAS_IPV6
1387 help
1388 Provide implementations for DNS resolver functions.
1389 In particular, the following functions will be added to the
1390 library:
1392 ns_skiprr, ns_initparse, ns_parserr, ns_msg_getflag,
1393 res_mkquery, res_init, res_ninit, res_close, res_nclose
1394 res_query, res_search, res_querydomain,
1395 dn_expand, dn_comp,
1396 ns_name_uncompress, ns_name_ntop, ns_name_pton, ns_name_unpack,
1397 ns_name_pack, ns_name_compress, ns_name_skip, dn_skipname,
1398 ns_get16, ns_get32, ns_put16, ns_put32
1400 config UCLIBC_HAS_LIBRESOLV_STUB
1401 bool "Provide libresolv stub"
1402 help
1403 Provide a dummy resolv library.
1405 config UCLIBC_HAS_LIBNSL_STUB
1406 bool "Provide libnsl stub"
1407 help
1408 Provide a dummy nsl library.
1410 endif
1413 menu "String and Stdio Support"
1415 config UCLIBC_HAS_STRING_GENERIC_OPT
1416 bool "Use faster (but larger) generic string functions"
1417 default y
1418 help
1419 Answer Y to use the (tweaked) glibc generic string functions.
1421 In general, they are faster (but 3-5K larger) than the base
1422 uClibc string functions which are optimized solely for size.
1424 Many people will answer Y.
1426 config UCLIBC_HAS_STRING_ARCH_OPT
1427 bool "Use arch-specific assembly string functions (where available)"
1428 default y
1429 help
1430 Answer Y to use any archtecture-specific assembly language string
1431 functions available for this target plaform.
1433 Note that assembly implementations are not available for all string
1434 functions, so some generic (written in C) string functions may
1435 still be used.
1437 These are small and fast, the only reason _not_ to say Y here is
1438 for debugging purposes.
1440 config UCLIBC_HAS_STDIO_FUTEXES
1441 bool "Use futexes for multithreaded I/O locking"
1442 depends on UCLIBC_HAS_THREADS_NATIVE
1443 help
1444 If you want to compile uClibc to use futexes for low-level
1445 I/O locking, answer Y. Otherwise, answer N.
1447 config UCLIBC_HAS_CTYPE_TABLES
1448 bool "Use Table Versions Of 'ctype.h' Functions."
1449 default y
1450 help
1451 Answer Y to use table versions of the 'ctype.h' functions.
1452 While the non-table versions are often smaller when building
1453 statically linked apps, they work only in stub locale mode.
1455 Most people will answer Y.
1457 config UCLIBC_HAS_CTYPE_SIGNED
1458 bool "Support Signed Characters In 'ctype.h' Functions."
1459 depends on UCLIBC_HAS_CTYPE_TABLES
1460 default y
1461 help
1462 Answer Y to enable support for passing signed char values to
1463 the 'ctype.h' functions. ANSI/ISO C99 and SUSv3 specify that
1464 these functions are only defined for unsigned char values and
1465 EOF. However, glibc allows negative signed char values as well
1466 in order to support 'broken old programs'.
1468 Most people will answer Y.
1470 choice
1471 prompt "ctype argument checking"
1472 depends on UCLIBC_HAS_CTYPE_TABLES
1473 default UCLIBC_HAS_CTYPE_UNSAFE
1474 help
1475 Please select the invalid arg behavior you want for the 'ctype'
1476 functions.
1478 The 'ctype' functions are now implemented using table lookups, with
1479 the arg being the index. This can result in incorrect memory accesses
1480 or even segfaults for args outside of the allowed range.
1482 NOTE: This only affects the 'ctype' _functions_. It does not affect
1483 the macro implementations.
1485 config UCLIBC_HAS_CTYPE_UNSAFE
1486 bool "Do not check -- unsafe"
1488 config UCLIBC_HAS_CTYPE_CHECKED
1489 bool "Detect and handle appropriately"
1491 config UCLIBC_HAS_CTYPE_ENFORCED
1492 bool "Issue a diagnostic and abort()"
1494 endchoice
1497 config UCLIBC_HAS_WCHAR
1498 bool "Wide Character Support"
1499 help
1500 Answer Y to enable wide character support. This will make uClibc
1501 much larger. It is also currently required for locale support.
1503 Most people will answer N.
1505 config UCLIBC_HAS_LOCALE
1506 bool "Locale Support"
1507 select UCLIBC_HAS_WCHAR
1508 select UCLIBC_HAS_CTYPE_TABLES
1509 help
1510 uClibc now has full ANSI/ISO C99 locale support (except for
1511 wcsftime() and collating items in regex). Be aware that enabling
1512 this option will make uClibc much larger.
1514 Enabling UCLIBC_HAS_LOCALE with the default set of supported locales
1515 (169 UTF-8 locales, and 144 locales for other codesets) will enlarge
1516 uClibc by around 300k. You can reduce this size by building your own
1517 custom set of locate data (see extra/locale/LOCALES for details).
1519 uClibc's locale support is still under development. For example,
1520 codesets using shift states are not currently supported. Support is
1521 planned in the next iteration of locale support.
1523 Answer Y to enable locale support. Most people will answer N.
1525 choice
1527 prompt "Locale data"
1528 depends on UCLIBC_HAS_LOCALE
1529 default UCLIBC_BUILD_MINIMAL_LOCALE
1531 config UCLIBC_BUILD_MINIMAL_LOCALE
1532 bool "Only selected locales"
1533 depends on UCLIBC_HAS_LOCALE
1534 help
1535 If you do not need all locales that are available on your
1536 host-box, then set this to 'Y'.
1538 config UCLIBC_BUILD_ALL_LOCALE
1539 bool "All locales"
1540 depends on UCLIBC_HAS_LOCALE
1541 help
1542 This builds all the locales that are available on your
1543 host-box.
1545 endchoice
1547 config UCLIBC_BUILD_MINIMAL_LOCALES
1548 string "locales to use"
1549 depends on UCLIBC_BUILD_MINIMAL_LOCALE
1550 default "en_US"
1551 help
1552 Space separated list of locales to use.
1554 E.g.:
1555 en_US en_GB de_AT
1556 default:
1557 en_US
1559 config UCLIBC_HAS_XLOCALE
1560 bool "Extended Locale Support (experimental/incomplete)"
1561 depends on UCLIBC_HAS_LOCALE
1562 help
1563 Answer Y to enable extended locale support similar to that provided
1564 by glibc. This is primarily intended to support libstd++
1565 functionality.
1566 However, it also allows thread-specific locale selection via
1567 uselocale().
1569 Most people will answer N.
1571 config UCLIBC_HAS_HEXADECIMAL_FLOATS
1572 bool "Support hexadecimal float notation"
1573 depends on UCLIBC_HAS_CTYPE_TABLES
1574 depends on UCLIBC_HAS_FLOATS
1575 help
1576 Answer Y to enable support for hexadecimal float notation in the
1577 (wchar and) char string to floating point conversion functions, as
1578 well as support for the %a and %A conversion specifiers in the
1579 *printf() and *scanf() functions.
1581 Most people will answer N.
1583 config UCLIBC_HAS_GLIBC_DIGIT_GROUPING
1584 bool "Support glibc's \"'\" flag for allowing locale-specific digit grouping"
1585 depends on UCLIBC_HAS_LOCALE
1586 depends on UCLIBC_HAS_FLOATS
1587 help
1588 Answer Y to enable support for glibc's \"'\" flag for allowing
1589 locale-specific digit grouping in base 10 integer conversions and
1590 appropriate floating point conversions in the *printf() and *scanf()
1591 functions.
1593 Most people will answer N.
1595 config UCLIBC_HAS_SCANF_LENIENT_DIGIT_GROUPING
1596 bool "Do not require digit grouping when the \"'\" flag is specified"
1597 depends on UCLIBC_HAS_GLIBC_DIGIT_GROUPING
1598 default y
1599 help
1600 Answer Y to make digit grouping optional when the \"'\" flag is
1601 specified.
1602 This is the standard glibc behavior. If the initial string of digits
1603 exceeds the maximum group number, the input will be treated as a
1604 normal non-grouped number.
1606 Most people will answer N.
1608 config UCLIBC_HAS_GLIBC_CUSTOM_PRINTF
1609 bool "Support glibc's register_printf_function() (glibc-compat)"
1610 depends on !USE_OLD_VFPRINTF
1611 help
1612 Answer Y to support glibc's register_printf_function() to allow an
1613 application to add its own printf conversion specifiers.
1614 parse_printf_format() is also enabled.
1616 NOTE: Limits the number or registered specifiers to 10.
1617 NOTE: Requires new conversion specifiers to be ASCII
1618 characters (0-0x7f). This is to avoid problems with processing
1619 format strings in locales with different multibyte conversions.
1621 Most people will answer N.
1623 config USE_OLD_VFPRINTF
1624 bool "Use the old vfprintf implementation"
1625 depends on !UCLIBC_HAS_WCHAR
1626 help
1627 Set to true to use the old vfprintf instead of the new. This is
1628 roughly C89 compliant with some extensions, and is much smaller.
1629 However, it does not support wide chars, positional args, or glibc
1630 custom printf specifiers.
1632 Most people will answer N.
1634 config UCLIBC_PRINTF_SCANF_POSITIONAL_ARGS
1635 int "Maximum number of positional args. Either 0 or >= 9."
1636 depends on !USE_OLD_VFPRINTF
1637 default 9
1638 help
1639 Set the maximum number of positional args supported by the
1640 printf/scanf functions. The Single Unix Specification Version 3
1641 requires a minimum value of 9. Setting this to a value lower than
1642 9 will disable positional arg support and cause the NL_ARGMAX macro
1643 in limits.h to be #undef'd.
1645 WARNING! The workspace to support positional args is currently
1646 allocated on the stack. You probably don't want to set
1647 this to too high a value.
1649 Most people will answer 9.
1651 choice
1652 prompt "Stdio buffer size"
1653 default UCLIBC_HAS_STDIO_BUFSIZ_4096
1654 help
1655 Please select a value for BUFSIZ. This will be used by the
1656 stdio subsystem as the default buffer size for a file, and
1657 affects fopen(), setvbuf(), etc.
1659 NOTE: Setting this to 'none' will disable buffering completely.
1660 However, BUFSIZ will still be defined in stdio.h as 256 because
1661 many applications use this value.
1663 config UCLIBC_HAS_STDIO_BUFSIZ_NONE
1664 bool "none (WARNING - BUFSIZ will be 256 in stdio.h)"
1665 depends on !UCLIBC_HAS_WCHAR
1667 config UCLIBC_HAS_STDIO_BUFSIZ_256
1668 bool "256 (minimum ANSI/ISO C99 value)"
1670 config UCLIBC_HAS_STDIO_BUFSIZ_512
1671 bool "512"
1673 config UCLIBC_HAS_STDIO_BUFSIZ_1024
1674 bool "1024"
1676 config UCLIBC_HAS_STDIO_BUFSIZ_2048
1677 bool "2048"
1679 config UCLIBC_HAS_STDIO_BUFSIZ_4096
1680 bool "4096"
1682 config UCLIBC_HAS_STDIO_BUFSIZ_8192
1683 bool "8192"
1685 # If you add more choices, you will need to update uClibc_stdio.h.
1687 endchoice
1689 choice
1690 prompt "Stdio builtin buffer size (uClibc-specific)"
1691 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1692 default UCLIBC_HAS_STDIO_BUILTIN_BUFFER_NONE
1693 help
1694 When a FILE is created with fopen(), an attempt is made to allocate
1695 a BUFSIZ buffer for it. If the allocation fails, fopen() will still
1696 succeed but the FILE will be unbuffered.
1698 This option adds a small amount of space to each FILE to act as an
1699 emergency buffer in the event of a buffer allocation failure.
1701 Most people will answer None.
1703 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_NONE
1704 bool "None"
1706 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_4
1707 bool "4"
1709 config UCLIBC_HAS_STDIO_BUILTIN_BUFFER_8
1710 bool "8"
1712 # If you add more choices, you will need to update uClibc_stdio.h.
1714 endchoice
1716 config UCLIBC_HAS_STDIO_SHUTDOWN_ON_ABORT
1717 bool "Attempt to shutdown stdio subsystem when abort() is called."
1718 help
1719 ANSI/ISO C99 requires abort() to be asyn-signal-safe. So there was
1720 a behavioral change made in SUSv3. Previously, abort() was required
1721 to have the affect of fclose() on all open streams. The wording has
1722 been changed to "may" from "shall".
1724 Most people will answer N.
1726 config UCLIBC_HAS_STDIO_GETC_MACRO
1727 bool "Provide a macro version of getc()"
1728 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1729 default y
1730 help
1731 Provide a macro version of getc().
1733 Most people will answer Y.
1735 config UCLIBC_HAS_STDIO_PUTC_MACRO
1736 bool "Provide a macro version of putc()"
1737 depends on !UCLIBC_HAS_STDIO_BUFSIZ_NONE
1738 default y
1739 help
1740 Provide a macro version of putc().
1742 Most people will answer Y.
1744 config UCLIBC_HAS_STDIO_AUTO_RW_TRANSITION
1745 bool "Support auto-r/w transition"
1746 default y
1747 help
1748 Answer Y to enable the stdio subsystem to automaticly transition
1749 between reading and writing. This relaxes the ANSI/ISO C99
1750 requirement:
1752 When a file is opened with update mode ('+' as the second or third
1753 character in the list of mode argument values), both input and output
1754 may be performed on the associated stream. However, output shall not
1755 be directly followed by input without an intervening call to the
1756 fflush function or to a file positioning function (fseek, fsetpos,
1757 or rewind), and input shall not be directly followed by output without
1758 an intervening call to a file positioning function, unless the input
1759 operation encounters endÂofÂfile.
1761 Most people will answer Y.
1763 config UCLIBC_HAS_FOPEN_LARGEFILE_MODE
1764 bool "Support an fopen() 'F' flag for large file mode (uClibc-specific)"
1765 depends on UCLIBC_HAS_LFS
1766 help
1767 Answer Y to enable a uClibc-specific extension to allow passing an
1768 additional 'F' flag in the mode string for fopen() to specify that
1769 the file should be open()ed with the O_LARGEFILE flag set.
1771 Most people will answer N.
1773 config UCLIBC_HAS_FOPEN_EXCLUSIVE_MODE
1774 bool "Support an fopen() 'x' flag for exclusive mode (glibc-compat)"
1775 help
1776 Answer Y to support a glibc extension to allow passing
1777 additional 'x' flag in the mode string for fopen() to specify that
1778 the file should be open()ed with the O_EXCL flag set.
1780 Most people will answer N.
1782 config UCLIBC_HAS_FOPEN_CLOSEEXEC_MODE
1783 bool "Support an fopen() 'e' flag for close-on-exec mode (glibc-compat)"
1784 help
1785 Answer Y to support a glibc extension to allow passing
1786 additional 'e' flag in the mode string for fopen() to specify that
1787 the file should be open()ed with the O_CLOEXEC flag set.
1789 Most people will answer N.
1791 config UCLIBC_HAS_GLIBC_CUSTOM_STREAMS
1792 bool "Support fmemopen(), open_memstream(), and fopencookie() (glibc-compat)"
1793 help
1794 Answer Y to support the glibc 'custom stream' extension functions
1795 fmemopen(), open_memstream(), and fopencookie().
1797 NOTE: There are some minor differences regarding seeking behavior.
1799 Most people will answer N.
1801 config UCLIBC_HAS_PRINTF_M_SPEC
1802 bool "Support the '%m' specifier in printf format strings (glibc-compat)"
1803 help
1804 Answer Y to support a glibc extension to interpret '%m' in printf
1805 format strings as an instruction to output the error message string
1806 (as generated by strerror) corresponding to the current value of
1807 'errno'.
1809 Most people will answer N.
1811 config UCLIBC_HAS_ERRNO_MESSAGES
1812 bool "Include the errno message text in the library"
1813 default y
1814 help
1815 Answer Y if you want to include the errno message text in the
1816 library. This adds about 3K to the library, but enables strerror()
1817 to generate text other than 'Unknown error <number>'.
1819 Most people will answer Y.
1821 config UCLIBC_HAS_SYS_ERRLIST
1822 bool "Support sys_errlist[] (obsolete-compat)"
1823 depends on UCLIBC_HAS_ERRNO_MESSAGES
1824 help
1825 Answer Y if you want to support the obsolete sys_errlist[].
1826 This adds about 0.5k to the library, except for the mips
1827 arch where it adds over 4K.
1829 WARNING! In the future, support for sys_errlist[] may be unavailable
1830 in at least some configurations. In fact, it may be removed
1831 altogether.
1833 Most people will answer N.
1835 Application writers: use the strerror(3) function.
1837 config UCLIBC_HAS_SIGNUM_MESSAGES
1838 bool "Include the signum message text in the library"
1839 default y
1840 help
1841 Answer Y if you want to include the signum message text in the
1842 library. This adds about 0.5K to the library, but enables strsignal()
1843 to generate text other than 'Unknown signal <number>'.
1845 Most people will answer Y.
1847 config UCLIBC_HAS_SYS_SIGLIST
1848 bool "Support sys_siglist[] (bsd-compat)"
1849 depends on UCLIBC_HAS_SIGNUM_MESSAGES
1850 help
1851 Answer Y if you want to support sys_siglist[].
1853 WARNING! In the future, support for sys_siglist[] may be unavailable
1854 in at least some configurations. In fact, it may be removed
1855 altogether.
1857 Most people will answer N.
1859 config UCLIBC_HAS_GNU_GETOPT
1860 bool "Support gnu getopt"
1861 default y
1862 help
1863 Answer Y if you want to include full gnu getopt() instead of a
1864 (much smaller) SUSv3 compatible getopt().
1865 Note that getopt_long, getopt_long_only as well as getsubopt
1866 are implemented on top of this choice.
1868 Most people will answer Y.
1870 config UCLIBC_HAS_GETOPT_LONG
1871 bool "Support getopt_long/getopt_long_only (glibc-compat)"
1872 default y
1873 help
1874 Answer Y if you want to include getopt_long[_only()] used by many
1875 apps.
1877 Most people will answer Y.
1879 config UCLIBC_HAS_GNU_GETSUBOPT
1880 bool "Support getsubopt"
1881 default y
1882 help
1883 Answer Y if you want to include getsubopt().
1885 Most people will answer Y.
1887 config UCLIBC_HAS_ARGP
1888 bool "Support argp (as standalone shared object)"
1889 select UCLIBC_HAS_GETOPT_LONG
1890 select UCLIBC_HAS_GNU_GETOPT
1891 default n
1892 help
1893 Argp is an interface for parsing unix-style argument vectors. Unlike
1894 the common getopt interface, it provides many advanced features in
1895 addition to parsing options, such as automatic output in response to
1896 `--help' and `--version' options.
1897 A library can export an argp option parser, which programs can easily
1898 use in conjunction with their own option parser.
1899 A new shared object "libuargp" is created. The "libc.so" linker script
1900 contains the AS_NEEDED entry for getting the libuargp linked automatically.
1901 Argp support is needed by elfutils libdw.
1903 Most people can safely answer N.
1905 endmenu
1908 menu "Big and Tall"
1910 config UCLIBC_HAS_REGEX
1911 bool "Regular Expression Support"
1912 default y
1913 help
1914 POSIX regular expression code is really big -- 53k all by itself.
1915 If you don't use regular expressions, turn this off and save space.
1916 Of course, if you only statically link, leave this on, since it will
1917 only be included in your apps if you use regular expressions.
1919 config UCLIBC_HAS_REGEX_OLD
1920 bool "Use the older (stable) regular expression code"
1921 depends on UCLIBC_HAS_REGEX
1922 default y
1923 help
1924 There are two versions of regex. The older (stable) version has
1925 been in uClibc for quite a long time but hasn't seen too many
1926 updates. It also has some known issues when dealing with uncommon
1927 corner cases and multibyte/unicode strings. However, it is quite
1928 a bit smaller than the newer version.
1930 If the older version has worked for you and you don't need unicode
1931 support, then stick with the old version (and say Y here).
1932 Otherwise, you should use the new version (and say N here).
1934 config UCLIBC_HAS_FNMATCH
1935 bool "fnmatch Support"
1936 default y
1937 help
1938 POSIX fnmatch.
1940 config UCLIBC_HAS_FNMATCH_OLD
1941 bool "Use the older (stable) fnmatch code"
1942 depends on UCLIBC_HAS_FNMATCH
1943 default y
1944 help
1945 There are two versions of fnmatch. The older (stable) version has
1946 been in uClibc for quite a long time but hasn't seen too many
1947 updates. It also has some known issues when dealing with uncommon
1948 corner cases and multibyte/unicode strings. However, it is quite
1949 a bit smaller than the newer version.
1951 If the older version has worked for you and you don't need unicode
1952 support, then stick with the old version (and say Y here).
1953 Otherwise, you should use the new version (and say N here).
1955 config UCLIBC_HAS_WORDEXP
1956 bool "Support the wordexp() interface"
1957 depends on UCLIBC_HAS_GLOB
1958 help
1959 The SuSv3 wordexp() interface performs word expansions per the Shell
1960 and Utilities volume of IEEE Std 1003.1-2001, Section 2.6. It is
1961 intended for use by applications that want to implement all of the
1962 standard Bourne shell expansions on input data.
1964 This interface is rarely used, and very large. Unless you have a
1965 pressing need for wordexp(), you should probably answer N.
1967 config UCLIBC_HAS_NFTW
1968 bool "Support the nftw() interface"
1969 help
1970 The SuSv3 nftw() interface is used to recursively descend
1971 directory paths while repeatedly calling a function.
1973 This interface is rarely used, and adds around 4.5k. Unless you have
1974 a pressing need for nftw(), you should probably answer N.
1976 config UCLIBC_HAS_FTW
1977 bool "Support the ftw() interface (SUSv4-obsolete)"
1978 depends on UCLIBC_SUSV4_LEGACY
1979 help
1980 The SuSv3 ftw() interface is used to recursively descend
1981 directory paths while repeatedly calling a function.
1983 This interface is rarely used, and adds around 4.5k. Unless you have
1984 a pressing need for ftw(), you should probably answer N.
1986 config UCLIBC_HAS_FTS
1987 bool "Support the fts() interface (bsd-compat)"
1988 help
1989 The fts functions are provided for traversing UNIX file hierarchies.
1991 This interface is currently used by the elfutils and adds
1992 around 7.5k.
1993 You should port your application to use the POSIX nftw()
1994 interface.
1996 Unless you need to build/use elfutils, you should prolly answer N.
1998 config UCLIBC_HAS_GLOB
1999 bool "Support the glob() interface"
2000 depends on UCLIBC_HAS_FNMATCH
2001 default y
2002 help
2004 The glob interface is somewhat large (weighing in at about 2,5k). It
2005 is used fairly often, but is an option since people wanting to go for
2006 absolute minimum size may wish to omit it.
2008 Most people will answer Y.
2010 config UCLIBC_HAS_GNU_GLOB
2011 bool "Support gnu glob() interface"
2012 depends on UCLIBC_HAS_GLOB
2013 help
2014 The gnu glob interface is somewhat larger (weighing in at about 4,2k)
2015 than it's SuSv3 counterpart (and is out of date). It is an old copy
2016 from glibc and does not support all the GNU specific options.
2018 Answer Y if you want to include full gnu glob() instead of the smaller
2019 SUSv3 compatible glob().
2021 Most people will answer N.
2023 endmenu
2028 menu "Library Installation Options"
2030 config RUNTIME_PREFIX
2031 string "uClibc runtime library directory"
2032 default "/usr/$(TARGET_ARCH)-linux-uclibc/"
2033 help
2034 RUNTIME_PREFIX is the directory into which the uClibc runtime
2035 libraries will be installed. The result will look something
2036 like the following:
2037 $(RUNTIME_PREFIX)/
2038 lib/ <contains all runtime libraries>
2039 usr/bin/ldd <the ldd utility program>
2040 sbin/ldconfig <the ldconfig utility program>
2041 This value is used by the 'make install' Makefile target. Since this
2042 directory is compiled into the shared library loader, you will need to
2043 recompile uClibc if you change this value...
2045 For a typical target system this should be set to "/", such that
2046 'make install' will install /lib/libuClibc-<VERSION>.so
2048 config DEVEL_PREFIX
2049 string "uClibc development environment directory"
2050 default "/usr/$(TARGET_ARCH)-linux-uclibc/usr/"
2051 help
2052 DEVEL_PREFIX is the directory into which the uClibc development
2053 environment will be installed. The result will look something
2054 like the following:
2055 $(DEVEL_PREFIX)/
2056 lib/ <contains static libs>
2057 include/ <Where all the header files go>
2058 This value is used by the 'make install' Makefile target when
2059 installing a uClibc development environment.
2061 For a typical target system this should be set to "/usr", such that
2062 'make install' will install /usr/include/<header files>.
2064 config MULTILIB_DIR
2065 string "library path component"
2066 default "lib"
2067 help
2068 Path component where libraries reside.
2070 For a typical target system this should be set to "lib", such that
2071 'make install' will install libraries to "/lib" and "/usr/lib"
2072 respectively
2073 DEVEL_PREFIX/MULTILIB_DIR
2074 RUNTIME_PREFIX/MULTILIB_DIR
2076 Other settings may include "lib32" or "lib64".
2078 config HARDWIRED_ABSPATH
2079 bool "Hardwire absolute paths into linker scripts"
2080 default y
2081 help
2082 This prepends absolute paths to the libraries mentioned in linker
2083 scripts such as libc.so.
2085 This is a build time optimization. It has no impact on dynamic
2086 linking at runtime, which doesn't use linker scripts.
2088 You must disable this to use uClibc with old non-sysroot toolchains,
2089 such as the prebuilt binary cross compilers at:
2090 http://uclibc.org/downloads/binaries
2092 The amount of time saved by this optimization is actually too small to
2093 measure. The linker just had to search the library path to find the
2094 linker script, so the dentries are cache hot if it has to search the
2095 same path again. But it's what glibc does, so we do it too.
2097 endmenu
2100 menu "Security options"
2102 config UCLIBC_BUILD_PIE
2103 bool "Build utilities as ET_DYN/PIE executables"
2104 depends on HAVE_SHARED
2105 depends on TARGET_arm || TARGET_frv || TARGET_i386 || TARGET_mips || TARGET_powerpc || TARGET_nds32
2106 select FORCE_SHAREABLE_TEXT_SEGMENTS
2107 help
2108 If you answer Y here, ldd and iconv are built as ET_DYN/PIE
2109 executables.
2111 It requires gcc-3.4 and binutils-2.15 (for arm 2.16) or later.
2112 More about ET_DYN/PIE binaries on <http://pax.grsecurity.net/> .
2114 WARNING: This option also enables FORCE_SHAREABLE_TEXT_SEGMENTS, so
2115 all libraries have to be built with -fPIC or -fpic, and all
2116 assembler functions must be written as position independent
2117 code (PIC).
2119 config UCLIBC_HAS_ARC4RANDOM
2120 bool "Include the arc4random() function"
2121 help
2122 Answer Y to support the OpenBSD-like arc4random() function. This
2123 function picks a random number between 0 and N, and will always return
2124 something even if the random driver is dead. If urandom fails then
2125 gettimeofday(2) will be used as the random seed. This function is
2126 designed to be more dependable than invoking /dev/urandom directly.
2127 OpenSSL and OpenNTPD currently support this function.
2129 Most people will answer N.
2131 config ARC4RANDOM_USES_NODEV
2132 bool "Do not use /dev/urandom with arc4random()"
2133 depends on UCLIBC_HAS_ARC4RANDOM
2134 help
2135 Answer Y to use gettimeofday(2) and getpid(2) exclusively for
2136 arc4random(). This is not a bad idea for a diskless system, but
2137 it uses a lot of syscalls to stir each array element.
2139 Most people will answer N.
2141 config HAVE_NO_SSP
2142 bool
2144 config UCLIBC_HAS_SSP
2145 bool "Support for GCC stack smashing protector"
2146 depends on !HAVE_NO_SSP
2147 help
2148 Add code to support GCC's -fstack-protector[-all] option to uClibc.
2149 This requires GCC 4.1 or newer. GCC does not have to provide libssp,
2150 the needed functions are added to ldso/libc instead.
2152 GCC's stack protector is a reimplementation of IBM's propolice.
2153 See http://www.trl.ibm.com/projects/security/ssp/ and
2154 http://www.linuxfromscratch.org/hints/downloads/files/ssp.txt
2155 for details.
2157 Note that NOEXECSTACK on a kernel with address space randomization
2158 is generally sufficient to prevent most buffer overflow exploits
2159 without increasing code size. This option essentially adds debugging
2160 code to catch them.
2162 Most people will answer N.
2164 config SSP_QUICK_CANARY
2165 bool "Use simple guard values without accessing /dev/urandom"
2166 depends on UCLIBC_HAS_SSP
2167 help
2168 Use gettimeofday(2) to define the __guard without accessing
2169 /dev/urandom.
2170 WARNING: This makes smashing stack protector vulnerable to timing
2171 attacks.
2172 Most people will answer N.
2174 choice
2175 prompt "Propolice protection blocking signal"
2176 depends on UCLIBC_HAS_SSP
2177 depends on DODEBUG
2178 default PROPOLICE_BLOCK_SEGV
2179 help
2180 "abort" use SIGABRT to block offending programs.
2181 This is the default implementation.
2183 "segfault" use SIGSEGV to block offending programs.
2184 Use this for debugging.
2186 If unsure, answer "abort".
2188 config PROPOLICE_BLOCK_ABRT
2189 bool "abort"
2191 config PROPOLICE_BLOCK_SEGV
2192 bool "segfault"
2194 endchoice
2196 config UCLIBC_BUILD_SSP
2197 bool "Build uClibc with -fstack-protector"
2198 depends on UCLIBC_HAS_SSP
2199 help
2200 Build all uClibc libraries and executables with -fstack-protector,
2201 adding extra stack overflow checking to most uClibc functions.
2203 config UCLIBC_BUILD_RELRO
2204 bool "Build uClibc with linker option -z RELRO"
2205 depends on HAVE_SHARED
2206 default y
2207 help
2208 Build all libraries and executables with "ld -z relro".
2210 This tells the linker to mark chunks of an executable or shared
2211 library read-only after applying dynamic relocations. (This comes
2212 up when a global const variable is initialized to the address of a
2213 function or the value of another global variable.)
2215 This is a fairly obscure option the ld man page doesn't even bother
2216 to document properly. It's a security paranoia issue that's more
2217 likely to consume memory (by allocating an extra page) rather than
2218 save it.
2220 This is explained in more depth at
2221 http://www.airs.com/blog/archives/189
2223 Nobody is likely to care whether you say Y or N here.
2225 config UCLIBC_BUILD_NOW
2226 bool "Build uClibc with linker option -z NOW"
2227 depends on HAVE_SHARED
2228 help
2229 Build all libraries and executables with "ld -z now".
2231 This tells the linker to resolve all symbols when the library is
2232 first loaded, rather than when each function is first called. This
2233 increases start-up latency by a few microseconds and may do
2234 unnecessary work (resolving symbols that are never used), but the
2235 realtime people like it for making microbenchmark timings slightly
2236 more predictable and in some cases it can be slightly faster due to
2237 CPU cache behavior (not having to fault the linker back in to do
2238 lazy symbol resolution).
2240 Most people can't tell the difference between selecting Y or N here.
2242 config UCLIBC_BUILD_NOEXECSTACK
2243 bool "Build uClibc with noexecstack marking"
2244 default y
2245 help
2246 Mark all assembler files as noexecstack, which will mark uClibc
2247 as not requiring an executable stack. (This doesn't prevent other
2248 files you link against from claiming to need an executable stack, it
2249 just won't cause uClibc to request it unnecessarily.)
2251 This is a security thing to make buffer overflows harder to exploit.
2252 By itself, it's kind of useless, as Linus Torvalds explained in 1998:
2253 http://old.lwn.net/1998/0806/a/linus-noexec.html
2255 It only actually provides any security when combined with address
2256 space randomization, explained here: http://lwn.net/Articles/121845/
2258 Address space randomization is on by default in current linux
2259 kernels (although it can be disabled using the option
2260 CONFIG_COMPAT_BRK).
2262 You should probably say Y.
2264 endmenu
2266 menu "Development/debugging options"
2268 config CROSS_COMPILER_PREFIX
2269 string "Cross-compiling toolchain prefix"
2270 default ""
2271 help
2272 The prefix used to execute your cross-compiling toolchain. For
2273 example, if you run 'arm-linux-uclibc-gcc' to compile something,
2274 then enter 'arm-linux-uclibc-' here.
2276 config UCLIBC_EXTRA_CFLAGS
2277 string "Extra CFLAGS"
2278 default ""
2279 help
2280 Add any additional CFLAGS to be used to build uClibc.
2282 config DODEBUG
2283 bool "Enable debugging symbols"
2284 select EXTRA_WARNINGS
2285 help
2286 Say Y here if you wish to compile uClibc with debugging symbols.
2287 This will allow you to use a debugger to examine uClibc internals
2288 while applications are running. This increases the size of the
2289 library considerably and should only be used when doing development.
2290 If you are doing development and want to debug uClibc, answer Y.
2292 Otherwise, answer N.
2294 config DODEBUG_PT
2295 bool "Build pthread with debugging output"
2296 depends on UCLIBC_HAS_THREADS && UCLIBC_HAS_LINUXTHREADS
2297 help
2298 Enable debug output in libpthread. This is only useful when doing
2299 development in libpthread itself.
2301 Otherwise, answer N.
2303 config DOSTRIP
2304 bool "Strip libraries and executables"
2305 default y
2306 depends on !DODEBUG
2307 help
2308 Say Y here if you do wish to strip all uClibc libraries and
2309 executables. No stripping increases the size of the binaries
2310 considerably, but makes it possible to debug uClibc libraries.
2311 Most people will answer Y.
2313 config DOASSERTS
2314 bool "Build with run-time assertion testing"
2315 help
2316 Say Y here to include runtime assertion tests.
2317 This enables runtime assertion testing in some code, which can
2318 increase the size of the library and incur runtime overhead.
2319 If you say N, then this testing will be disabled.
2321 config SUPPORT_LD_DEBUG
2322 bool "Build the shared library loader with debugging support"
2323 depends on HAVE_SHARED
2324 help
2325 Answer Y here to enable all the extra code needed to debug the uClibc
2326 native shared library loader. The level of debugging noise that is
2327 generated depends on the LD_DEBUG environment variable... Just set
2328 LD_DEBUG to something like: 'LD_DEBUG=token1,token2,.. prog' to
2329 debug your application. Diagnostic messages will then be printed to
2330 the stderr.
2332 For now these debugging tokens are available:
2333 detail provide more information for some options
2334 move display copy processing
2335 symbols display symbol table processing
2336 reloc display relocation processing; detail shows the
2337 relocation patch
2338 nofixups never fixes up jump relocations
2339 bindings displays the resolve processing (function calls);
2340 detail shows the relocation patch
2341 all Enable everything!
2343 The additional environment variable:
2344 LD_DEBUG_OUTPUT=file
2345 redirects the diagnostics to an output file created using
2346 the specified name and the process id as a suffix.
2348 An excellent start is simply:
2349 $ LD_DEBUG=binding,move,symbols,reloc,detail ./appname
2350 or to log everything to a file named 'logfile', try this
2351 $ LD_DEBUG=all LD_DEBUG_OUTPUT=logfile ./appname
2353 If you are doing development and want to debug uClibc's shared library
2354 loader, answer Y. Mere mortals answer N.
2356 config SUPPORT_LD_DEBUG_EARLY
2357 bool "Build the shared library loader with early debugging support"
2358 depends on HAVE_SHARED
2359 help
2360 Answer Y here to if you find the uClibc shared library loader is
2361 crashing or otherwise not working very early on. This is typical
2362 only when starting a new port when you haven't figured out how to
2363 properly get the values for argc, argv, environ, etc. This method
2364 allows a degree of visibility into the very early shared library
2365 loader initialization process. If you are doing development and want
2366 to debug the uClibc shared library loader early initialization,
2367 answer Y. Mere mortals answer N.
2369 config UCLIBC_MALLOC_DEBUGGING
2370 bool "Build malloc with debugging support"
2371 depends on MALLOC || MALLOC_STANDARD
2372 select DOASSERTS
2373 help
2374 Answer Y here to compile extra debugging support code into malloc.
2375 Malloc debugging output may then be enabled at runtime using the
2376 MALLOC_DEBUG environment variable.
2378 The value of MALLOC_DEBUG should be an integer, which is interpreted
2379 as a bitmask with the following bits:
2380 1 - do extra consistency checking
2381 2 - output messages for malloc/free calls and OS
2382 allocation calls
2383 4 - output messages for the `MMB' layer
2384 8 - output messages for internal malloc heap manipulation
2385 calls
2387 Because this increases the size of malloc appreciably (due to strings
2388 etc), you should say N unless you need to debug a malloc problem.
2390 config UCLIBC_HAS_BACKTRACE
2391 bool "Add support for application self-debugging"
2392 depends on HAVE_SHARED
2393 help
2394 Answer Y here to compile support for application self-debugging, by adding
2395 a new shared object "libubacktrace.so" that provides the following new
2396 functions:
2397 backtrace, backtrace_symbols, backtrace_symbols_fd
2399 The backtrace functionality is currently supported on SH platform, and it
2400 based on dwarf2 informations to properly work, so any application that
2401 want to use backtrace needs to be built with -fexceptions flag.
2403 The symbol names may be unavailable without the use of special linker
2404 options. For systems using the GNU linker, it is necessary to use the
2405 -rdynamic linker option too. Note that names of "static" functions are not
2406 exposed, and won't be available in the backtrace.
2408 config WARNINGS
2409 string "Compiler Warnings"
2410 default "-Wall"
2411 help
2412 Set this to the set of compiler warnings you wish to see while compiling.
2414 config EXTRA_WARNINGS
2415 bool "Enable extra annoying warnings"
2416 help
2417 If you wish to build with extra warnings enabled, say Y here.
2419 endmenu