X-Git-Url: https://git.librecmc.org/?a=blobdiff_plain;f=TODO;h=b3d950790f2d5bd236703440f68452fa119e292a;hb=0b656283959079825ecea5eba72f0b63e8fca913;hp=4653abfb2c8ac13cdcd809a9caa55524e3e35d26;hpb=b413a7009ec0058f00be9ae57097b151d22f29a4;p=oweals%2Fbusybox.git diff --git a/TODO b/TODO index 4653abfb2..b3d950790 100644 --- a/TODO +++ b/TODO @@ -1,61 +1,87 @@ Busybox TODO -Stuff that needs to be done +Stuff that needs to be done. All of this is fair game for 1.2. -tr - missing SuS3 features in busybox 1.0pre10 - -tr doesnt support [:blank:], [:digit:] or other predefined classes, [=equiv=] -support is also missing. +build system + make -j is broken, -j1 is forced atm + Make sure that the flags get pinned in e.g. Rules.mak so when expanding them + later on you get the cached result without the need to re-evaluate them. ---- find - doesn't understand () or -exec, and these are actually used out in the real - world. The "make uninstall" of lots of things (including busybox itself) - breaks because of this, and sometimes even "make install" (like udev). + doesn't understand (), lots of susv3 stuff. ---- -comm - Perl needs "comm" to build. It's small and simple, but we haven't got 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. Unifying the various shells and figuring out a configurable way of adding the minimal set of bash features a given script uses is a big - job, but it be a big improvement. ---- -gzip - Can't handle compressing multiple files at once. (I don't mean making a - multiple file archive, I mean compressing more than one file at a time.) - Some global variables aren't re-initialized between runs. ---- -gunzip - same problem as gzip. "gunzip one.gz two.gz three.gz" doesn't work for - two.gz and three.gz due to global variables not getting reset. + job, but it would be a big improvement. + + Note: Rob Landley (rob@landley.net) is working on a new unified shell called + bbsh, but it's a low priority... --- diff - We should have a diff -u command. We have patch, we should have diff - (we only need to support unified diffs though). + Also, 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 -i support, and simple fuzz factor support to apply patches - at an offset shouldn't take up too much space. + Should have simple fuzz factor support to apply patches at an offset which + shouldn't take up too much space. + + 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 --- 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/zcatbzcat | more ---- -less - More sucks if you're used to less. A tiny less implementation would be - very nice. + calls cat/zcat/bzcat | less + + (How doclifter might work into this is anybody's guess.) --- bzip2 Compression-side support. - +--- +init + General cleanup. +--- +ar + Write support? +--- +mdev + Micro-udev. +--- +crond + turn FEATURE_DEBUG_OPT into ENABLE_FEATURE_CROND_DEBUG_OPT 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 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 @@ -64,7 +90,30 @@ Do a SUSv3 audit 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? + + 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. + + 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"?) +--- 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 @@ -72,11 +121,11 @@ Unify archivers "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 someday, - if it becomes relevant. + write support, and possibly even cheaply add things like mkisofs or + mksquashfs someday, if they become relevant. --- Text buffer support. - Several existing applets and potential additions (sort, vi, less...) read + 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... --- @@ -91,17 +140,123 @@ Individual compilation of applets. got the code for (like zlib). --- buildroot - Make a "dogfood" option - Busybox is now capable of replacing most gnu packages for real world use, - such as developing software or in a live CD. A system built from busybox - (1.00 with updated sort.c), uclibc 0.9.27, gcc, binutils, make, and a few - other development tools (http://www.landley.net/code/firmware has an example - system using autoconf, automake, bison, flex, libtools, m4, zlib, - and groff: dunno what subset of that is actually necessary) is capable of - rebuilding itself, from scratch, under itself. + 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. + + 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 busybox instead of bzip2, coreutils, file, findutils, gawk, grep, - inetutils, modutils, net-tools, procps, sed, shadow, sysklogd, sysvinit, tar, - util-linux, and vim. 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, diffutils, gzip, less, and patch as well.) + 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.) + + 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. +--- +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 CFLAGS_EXTRA=-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 bb_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. + + +Code cleanup: + +Replace deprecated functions. + +bzero() -> memset() +--- +sigblock(), siggetmask(), sigsetmask(), sigmask() -> sigprocmask et al +--- +vdprintf() -> similar sized functionality +--- +