| 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>: |
| 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. |
| 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 |
| |
| 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 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 |
| --- |
| |