Busybox TODO 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. 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() 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). 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. 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"?) 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. 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. 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.) 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. Bernhard Fischer <rep.nop@anon.at>: Makefile stuff: make -j is broken, -j1 is forced atm New debug options: -Wlarger-than-127 Collate BUFSIZ IOBUF_SIZE MY_BUF_SIZE PIPE_PROGRESS_SIZE BUFSIZE PIPESIZE Use bb_common_bufsiz1? As yet unclaimed: ---- 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. 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/zcat/bzcat | less (How doclifter might work into this is anybody's guess.) --- ar Write support? --- 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 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 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. --- 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() --- unify itoa: netstat.c, hush.c, lash.c, msh.c Put one single, robust version into e.g. safe_strtol.c --- Code cleanup: Replace deprecated functions. bzero() -> memset() --- sigblock(), siggetmask(), sigsetmask(), sigmask() -> sigprocmask et al --- vdprintf() -> similar sized functionality ---