-TODO list for busybox in no particular order. Just because something
-is listed here doesn't mean that it is going to be added to busybox,
-or that doing so is even a good idea. It just means that I _might_ get
-around to it some time. If you have any good ideas, please let me know.
+Busybox TODO
-* login/sulogin/passwd/etc are part of tinylogin. We are in the
- process of merging these applications into busybox, since the
- new build system allows us to add Libraries (i.e. libcrypt),
- when certain applets are enabled.
+Stuff that needs to be done. This is organized by who plans to get around to
+doing it eventually, but that doesn't mean they "own" the item. If you want to
+do one of these bounce an email off the person it's listed under to see if they
+have any suggestions how they plan to go about it, and to minimize conflicts
+between your work and theirs. But otherwise, all of these are fair game.
-* We _were_ going to split networking apps into a new package called
- netkit-tiny. Per discussions on the mailing list, this isn't going
- to happen. False alarm. Sorry about the confusion.
+Rob Landley <rob@landley.net>:
+ Add BB_NOMMU to platform.h and migrate __uClinux__ tests to that.
+ #if defined __UCLIBC__ && !defined __ARCH_USE_MMU__
+ Add a libbb/platform.c
+ Implement fdprintf() for platforms that haven't got one.
+ Implement bb_realpath() that can handle NULL on non-glibc.
+ Cleanup bb_asprintf()
- -Erik
+ Migrate calloc() and bb_calloc() occurrences to bb_xzalloc().
+ Remove obsolete _() wrapper crud for internationalization we don't do.
+ Figure out where we need utf8 support, and add it.
------------
+ sh
+ The command shell situation is a big mess. We have three or four different
+ shells that don't really share any code, and the "standalone shell" doesn't
+ work all that well (especially not in a chroot environment), due to apps not
+ being reentrant. I'm writing a new shell (bbsh) to unify the various
+ shells and configurably add the minimal set of bash features people
+ actually use. The hardest part is it has to configure down as small as
+ lash while providing lash's features. The rest is easy in comparison.
+ bzip2
+ Compression-side support.
+ init
+ General cleanup (should use ENABLE_FEATURE_INIT_SYSLOG and ENABLE_FEATURE_INIT_DEBUG).
+ depmod
+ busybox lacks a way to update module deps when running from firmware without the
+ use of the depmod.pl (perl is to bloated for most embedded setups) and or orig
+ modutils. The orig depmod is rather pointless to have to add to a firmware image
+ in when we already have a insmod/rmmod and friends.
+ Unify base64 handling.
+ There's base64 encoding and decoding going on in:
+ networking/wget.c:base64enc()
+ coreutils/uudecode.c:read_base64()
+ coreutils/uuencode.c:tbl_base64[]
+ networking/httpd.c:decodeBase64()
+ And probably elsewhere. That needs to be unified into libbb functions.
+ Do a SUSv3 audit
+ Look at the full Single Unix Specification version 3 (available online at
+ "http://www.opengroup.org/onlinepubs/009695399/nfindex.html") and
+ figure out which of our apps are compliant, and what we're missing that
+ we might actually care about.
-Possible apps to include some time:
+ Even better would be some kind of automated compliance test harness that
+ exercises each command line option and the various corner cases.
+ Internationalization
+ How much internationalization should we do?
-* hwclock
-* group/commonize strings, remove dups (for i18n, l10n)
-* login/sulogin/passwd/etc are part of tinylogin. These are
- being merged into busybox as time allows.
+ The low hanging fruit is UTF-8 character set support. We should do this.
+ (Vodz pointed out the shell's cmdedit as needing work here. What else?)
------------
+ We also have lots of hardwired english text messages. Consolidating this
+ into some kind of message table not only makes translation easier, but
+ also allows us to consolidate redundant (or close) strings.
-With sysvinit, reboot, poweroff and halt all used a named pipe,
-/dev/initctl, to communicate with the init process. Busybox
-currently uses signals to communicate with init. This makes
-busybox incompatible with sysvinit. We should probably use
-a named pipe as well so we can be compatible.
+ We probably don't want to be bloated with locale support. (Not unless we
+ can cleanly export it from our underlying C library without having to
+ concern ourselves with it directly. Perhaps a few specific things like a
+ config option for "date" are low hanging fruit here?)
------------------------
+ What level should things happen at? How much do we care about
+ internationalizing the text console when X11 and xterms are so much better
+ at it? (There's some infrastructure here we don't implement: The
+ "unicode_start" and "unicode_stop" shell scripts need "vt-is-UTF8" and a
+ --unicode option to loadkeys. That implies a real loadkeys/dumpkeys
+ implementation to replace loadkmap/dumpkmap. Plus messing with console font
+ loading. Is it worth it, or do we just say "use X"?)
-Run the following:
+ Individual compilation of applets.
+ It would be nice if busybox had the option to compile to individual applets,
+ for people who want an alternate implementation less bloated than the gnu
+ utils (or simply with less political baggage), but without it being one big
+ executable.
- rm -f busybox && make LDFLAGS+=-nostdlib 2>&1 | \
- sed -ne 's/.*undefined reference to `\(.*\)..*/\1/gp' | sort | uniq
+ Turning libbb into a real dll is another possibility, especially if libbb
+ could export some of the other library interfaces we've already more or less
+ got the code for (like zlib).
+ buildroot - Make a "dogfood" option
+ Busybox 1.1 will be capable of replacing most gnu packages for real world
+ use, such as developing software or in a live CD. It needs wider testing.
-reveals the list of all external (i.e., libc) things that BusyBox depends on.
-It would be a very nice thing to reduce this list to an absolute minimum, to
-reduce the footprint of busybox, especially when staticly linking with
-libraries such as uClibc.
+ Busybox should now be able to replace bzip2, coreutils, e2fsprogs, file,
+ findutils, gawk, grep, inetutils, less, modutils, net-tools, patch, procps,
+ sed, shadow, sysklogd, sysvinit, tar, util-linux, and vim. The resulting
+ system should be self-hosting (I.E. able to rebuild itself from source
+ code). This means it would need (at least) binutils, gcc, and make, or
+ equivalents.
------------------------
+ It would be a good "eating our own dogfood" test if buildroot had the option
+ of using a "make allyesconfig" busybox instead of the all of the above
+ packages. Anything that's wrong with the resulting system, we can fix. (It
+ would be nice to be able to upgrade busybox to be able to replace bash and
+ diffutils as well, but we're not there yet.)
-Compile with debugging on, run 'nm --size-sort ./busybox'
-and then start with the biggest things and make them smaller...
+ One example of an existing system that does this already is Firmware Linux:
+ http://www.landley.net/code/firmware
+ initramfs
+ Busybox should have a sample initramfs build script. This depends on
+ bbsh, mdev, and switch_root.
+ mkdep
+ Write a mkdep that doesn't segfault if there's a directory it doesn't
+ have permission to read, isn't based on manually editing the output of
+ lexx and yacc, doesn't make such a mess under include/config, etc.
+ Group globals into unions of structures.
+ Go through and turn all the global and static variables into structures,
+ and have all those structures be in a big union shared between processes,
+ so busybox uses less bss. (This is a big win on nommu machines.) See
+ sed.c and mdev.c for examples.
+ Go through bugs.busybox.net and close out all of that somehow.
+ This one's open to everybody, but I'll wind up doing it...
------------------------
- du.c probably ought to have an -x switch like GNU du does...
+Bernhard Fischer <busybox@busybox.net> suggests to look at these:
+ New debug options:
+ -Wlarger-than-127
+ Cleanup any big users
+ -Wunused-parameter
+ Facilitate applet PROTOTYPES to provide means for having applets that
+ do a) not take any arguments b) need only one of argc or argv c) need
+ both argc and argv. All of these three options should go for the most
+ feature complete denominator.
+ Collate BUFSIZ IOBUF_SIZE MY_BUF_SIZE PIPE_PROGRESS_SIZE BUFSIZE PIPESIZE
+ make bb_common_bufsiz1 configurable, size wise.
+ make pipesize configurable, size wise.
+ Use bb_common_bufsiz1 throughout applets!
+ Add chrt applet. Please CC Bernhard if you suggest a patch.
------------------------
+As yet unclaimed:
-xargs could use a -l option
+----
+find
+ doesn't understand (), lots of susv3 stuff.
+----
+diff
+ Make sure we handle empty files properly:
+ From the patch man page:
-------------------------------------------------------------------
+ you can remove a file by sending out a context diff that compares
+ the file to be deleted with an empty file dated the Epoch. The
+ file will be removed unless patch is conforming to POSIX and the
+ -E or --remove-empty-files option is not given.
+---
+patch
+ Should have simple fuzz factor support to apply patches at an offset which
+ shouldn't take up too much space.
-libbb/unzip.c and archival/gzip.c have common constant static arrays and
-code for initializing the CRC array. Both use CRC-32 and could use
-common code for CRC calculation. Within archival/gzip.c, the CRC
-array should be malloc-ed as it is in libbb/unzip.c .
+ And while we're at it, a new patch filename quoting format is apparently
+ coming soon: http://marc.theaimsgroup.com/?l=git&m=112927316408690&w=2
+---
+ps / top
+ Add support for both RSS and VSIZE rather than just one or the other.
+ Or make it a build option.
+---
+man
+ It would be nice to have a man command. Not one that handles troff or
+ anything, just one that can handle preformatted ascii man pages, possibly
+ compressed. This could probably be a script in the extras directory that
+ calls cat/zcat/bzcat | less
+
+ (How doclifter might work into this is anybody's guess.)
+---
+ar
+ Write support?
+----
+stty / catv
+ stty's visible() function and catv's guts are identical. Merge them into
+ an appropriate libbb function.
+----
+struct suffix_mult
+ Several duplicate users of: grep -r "1024\*1024" * -B2 -A1
+ Merge to a single size_suffixes[] in libbb.
+ Users: head tail od_bloaty hexdump and (partially as it wouldn't hurt) svlogd
+
+Architectural issues:
+
+bb_close() with fsync()
+ We should have a bb_close() in place of normal close, with a CONFIG_ option
+ to not just check the return value of close() for an error, but fsync().
+ Close can't reliably report anything useful because if write() accepted the
+ data then it either went out to the network or it's in cache or a pipe
+ buffer. Either way, there's no guarantee it'll make it to its final
+ destination before close() gets called, so there's no guarantee that any
+ error will be reported.
+
+ You need to call fsync() if you care about errors that occur after write(),
+ but that can have a big performance impact. So make it a config option.
+---
+Unify archivers
+ Lots of archivers have the same general infrastructure. The directory
+ traversal code should be factored out, and the guts of each archiver could
+ be some setup code and a series of callbacks for "add this file",
+ "add this directory", "add this symlink" and so on.
+
+ This could clean up tar and zip, and make it cheaper to add cpio and ar
+ write support, and possibly even cheaply add things like mkisofs or
+ mksquashfs someday, if they become relevant.
+---
+Text buffer support.
+ Several existing applets (sort, vi, less...) read
+ a whole file into memory and act on it. There might be an opportunity
+ for shared code in there that could be moved into libbb...
+---
+Memory Allocation
+ We have a CONFIG_BUFFER mechanism that lets us select whether to do memory
+ allocation on the stack or the heap. Unfortunately, we're not using it much.
+ We need to audit our memory allocations and turn a lot of malloc/free calls
+ into RESERVE_CONFIG_BUFFER/RELEASE_CONFIG_BUFFER.
+ For a start, see e.g. make EXTRA_CFLAGS=-Wlarger-than-64
+
+ And while we're at it, many of the CONFIG_FEATURE_CLEAN_UP #ifdefs will be
+ optimized out by the compiler in the stack allocation case (since there's no
+ free for an alloca()), and this means that various cleanup loops that just
+ call free might also be optimized out by the compiler if written right, so
+ we can yank those #ifdefs too, and generally clean up the code.
+---
+Switch CONFIG_SYMBOLS to ENABLE_SYMBOLS
+
+ In busybox 1.0 and earlier, configuration was done by CONFIG_SYMBOLS
+ that were either defined or undefined to indicate whether the symbol was
+ selected in the .config file. They were used with #ifdefs, ala:
+
+ #ifdef CONFIG_SYMBOL
+ if (other_test) {
+ do_code();
+ }
+ #endif
+
+ In 1.1, we have new ENABLE_SYMBOLS which are always defined (as 0 or 1),
+ meaning you can still use them for preprocessor tests by replacing
+ "#ifdef CONFIG_SYMBOL" with "#if ENABLE_SYMBOL". But more importantly, we
+ can use them as a true or false test in normal C code:
+
+ if (ENABLE_SYMBOL && other_test) {
+ do_code();
+ }
+
+ (Optimizing away if() statements that resolve to a constant value
+ is known as "dead code elimination", an optimization so old and simple that
+ Turbo Pascal for DOS did it twenty years ago. Even modern mini-compilers
+ like the Tiny C Compiler (tcc) and the Small Device C Compiler (SDCC)
+ perform dead code elimination.)
+
+ Right now, busybox.h is #including both "config.h" (defining the
+ CONFIG_SYMBOLS) and "bb_config.h" (defining the ENABLE_SYMBOLS). At some
+ point in the future, it would be nice to wean ourselves off of the
+ CONFIG versions. (Among other things, some defective build environments
+ leak the Linux kernel's CONFIG_SYMBOLS into the system's standard #include
+ files. We've experienced collisions before.)
+---
+FEATURE_CLEAN_UP
+ This is more an unresolved issue than a to-do item. More thought is needed.
+
+ Normally we rely on exit() to free memory, close files, and unmap segments
+ for us. This makes most calls to free(), close(), and unmap() optional in
+ busybox applets that don't intend to run for very long, and optional stuff
+ can be omitted to save size.
+
+ The idea was raised that we could simulate fork/exit with setjmp/longjmp
+ for _really_ brainless embedded systems, or speed up the standalone shell
+ by not forking. Doing so would require a reliable FEATURE_CLEAN_UP.
+ Unfortunately, this isn't as easy as it sounds.
+
+ The problem is, lots of things exit(), sometimes unexpectedly (xmalloc())
+ and sometimes reliably (bb_perror_msg_and_die() or show_usage()). This
+ jumps out of the normal flow control and bypasses any cleanup code we
+ put at the end of our applets.
+
+ It's possible to add hooks to libbb functions like xmalloc() and xopen()
+ to add their entries to a linked list, which could be traversed and
+ freed/closed automatically. (This would need to be able to free just the
+ entries after a checkpoint to be usable for a forkless standalone shell.
+ You don't want to free the shell's own resources.)
+
+ Right now, FEATURE_CLEAN_UP is more or less a debugging aid, to make things
+ like valgrind happy. It's also documentation of _what_ we're trusting
+ exit() to clean up for us. But new infrastructure to auto-free stuff would
+ render the existing FEATURE_CLEAN_UP code redundant.
+
+ For right now, exit() handles it just fine.
+
+
+
+Minor stuff:
+ watchdog.c could autodetect the timer duration via:
+ if(!ioctl (fd, WDIOC_GETTIMEOUT, &tmo)) timer_duration = 1 + (tmo / 2);
+ Unfortunately, that needs linux/watchdog.h and that contains unfiltered
+ kernel types on some distros, which breaks the build.
+---
+ use bb_error_msg where appropriate: See
+ egrep "(printf.*\([[:space:]]*(stderr|2)|[^_]write.*\([[:space:]]*(stderr|2))"
+---
+ use bb_perror_msg where appropriate: See
+ egrep "[^_]perror"
+---
+ Remove superfluous fmt occurances: e.g.
+ fprintf(stderr, "%s: %s not found\n", "unalias", *argptr);
+ -> fprintf(stderr, "unalias: %s not found\n", *argptr);
+---
+ possible code duplication ingroup() and is_a_group_member()
+---
+ Move __get_hz() to a better place and (re)use it in route.c, ash.c, msh.c
+---
+
+
+Code cleanup:
+
+Replace deprecated functions.
+
+bzero() -> memset()
+---
+sigblock(), siggetmask(), sigsetmask(), sigmask() -> sigprocmask et al
+---
+vdprintf() -> similar sized functionality
+---
projects / oweals / busybox.git / blobdiff