1Busybox TODO 2 3Harvest patches from 4http://git.openembedded.org/cgit.cgi/openembedded/tree/recipes/busybox/ 5https://dev.openwrt.org/browser/trunk/package/busybox/patches/ 6 7 8Stuff that needs to be done. This is organized by who plans to get around to 9doing it eventually, but that doesn't mean they "own" the item. If you want to 10do one of these bounce an email off the person it's listed under to see if they 11have any suggestions how they plan to go about it, and to minimize conflicts 12between your work and theirs. But otherwise, all of these are fair game. 13 14Rob Landley suggested this: 15 Implement bb_realpath() that can handle NULL on non-glibc. 16 17 sh 18 The command shell situation is a mess. We have two different 19 shells that don't really share any code, and the "standalone shell" doesn't 20 work all that well (especially not in a chroot environment), due to apps not 21 being reentrant. 22 23 Do a SUSv3 audit 24 Look at the full Single Unix Specification version 3 (available online at 25 "http://www.opengroup.org/onlinepubs/009695399/nfindex.html") and 26 figure out which of our apps are compliant, and what we're missing that 27 we might actually care about. 28 29 Even better would be some kind of automated compliance test harness that 30 exercises each command line option and the various corner cases. 31 32 Internationalization 33 How much internationalization should we do? 34 35 The low hanging fruit is UTF-8 character set support. We should do this. 36 See TODO_unicode file. 37 38 We also have lots of hardwired english text messages. Consolidating this 39 into some kind of message table not only makes translation easier, but 40 also allows us to consolidate redundant (or close) strings. 41 42 We probably don't want to be bloated with locale support. (Not unless we 43 can cleanly export it from our underlying C library without having to 44 concern ourselves with it directly. Perhaps a few specific things like a 45 config option for "date" are low hanging fruit here?) 46 47 What level should things happen at? How much do we care about 48 internationalizing the text console when X11 and xterms are so much better 49 at it? (There's some infrastructure here we don't implement: The 50 "unicode_start" and "unicode_stop" shell scripts need "vt-is-UTF8" and a 51 --unicode option to loadkeys. That implies a real loadkeys/dumpkeys 52 implementation to replace loadkmap/dumpkmap. Plus messing with console font 53 loading. Is it worth it, or do we just say "use X"?) 54 55 Individual compilation of applets. 56 It would be nice if busybox had the option to compile to individual applets, 57 for people who want an alternate implementation less bloated than the gnu 58 utils (or simply with less political baggage), but without it being one big 59 executable. 60 61 Turning libbb into a real dll is another possibility, especially if libbb 62 could export some of the other library interfaces we've already more or less 63 got the code for (like zlib). 64 65 buildroot - Make a "dogfood" option 66 Busybox 1.1 will be capable of replacing most gnu packages for real world 67 use, such as developing software or in a live CD. It needs wider testing. 68 69 Busybox should now be able to replace bzip2, coreutils, e2fsprogs, file, 70 findutils, gawk, grep, inetutils, less, modutils, net-tools, patch, procps, 71 sed, shadow, sysklogd, sysvinit, tar, util-linux, and vim. The resulting 72 system should be self-hosting (I.E. able to rebuild itself from source 73 code). This means it would need (at least) binutils, gcc, and make, or 74 equivalents. 75 76 It would be a good "eating our own dogfood" test if buildroot had the option 77 of using a "make allyesconfig" busybox instead of the all of the above 78 packages. Anything that's wrong with the resulting system, we can fix. (It 79 would be nice to be able to upgrade busybox to be able to replace bash and 80 diffutils as well, but we're not there yet.) 81 82 One example of an existing system that does this already is Firmware Linux: 83 http://www.landley.net/code/firmware 84 85 initramfs 86 Busybox should have a sample initramfs build script. This depends on 87 shell, mdev, and switch_root. 88 89 mkdep 90 Write a mkdep that doesn't segfault if there's a directory it doesn't 91 have permission to read, isn't based on manually editing the output of 92 lexx and yacc, doesn't make such a mess under include/config, etc. 93 94 Group globals into unions of structures. 95 Go through and turn all the global and static variables into structures, 96 and have all those structures be in a big union shared between processes, 97 so busybox uses less bss. (This is a big win on nommu machines.) See 98 sed.c and mdev.c for examples. 99 100 Go through bugs.busybox.net and close out all of that somehow. 101 This one's open to everybody, but I'll wind up doing it... 102 103Bernhard Reutner-Fischer <busybox@busybox.net> suggests to look at these: 104 New debug options: 105 -Wlarger-than-127 106 Cleanup any big users 107 Collate BUFSIZ IOBUF_SIZE MY_BUF_SIZE PIPE_PROGRESS_SIZE BUFSIZE PIPESIZE 108 make bb_common_bufsiz1 configurable, size wise. 109 make pipesize configurable, size wise. 110 Use bb_common_bufsiz1 throughout applets! 111 112As yet unclaimed: 113 114---- 115diff 116 Make sure we handle empty files properly: 117 From the patch man page: 118 119 you can remove a file by sending out a context diff that compares 120 the file to be deleted with an empty file dated the Epoch. The 121 file will be removed unless patch is conforming to POSIX and the 122 -E or --remove-empty-files option is not given. 123--- 124patch 125 Should have simple fuzz factor support to apply patches at an offset which 126 shouldn't take up too much space. 127 128 And while we're at it, a new patch filename quoting format is apparently 129 coming soon: http://marc.theaimsgroup.com/?l=git&m=112927316408690&w=2 130 131Architectural issues: 132 133bb_close() with fsync() 134 We should have a bb_close() in place of normal close, with a CONFIG_ option 135 to not just check the return value of close() for an error, but fsync(). 136 Close can't reliably report anything useful because if write() accepted the 137 data then it either went out to the network or it's in cache or a pipe 138 buffer. Either way, there's no guarantee it'll make it to its final 139 destination before close() gets called, so there's no guarantee that any 140 error will be reported. 141 142 You need to call fsync() if you care about errors that occur after write(), 143 but that can have a big performance impact. So make it a config option. 144--- 145Unify archivers 146 Lots of archivers have the same general infrastructure. The directory 147 traversal code should be factored out, and the guts of each archiver could 148 be some setup code and a series of callbacks for "add this file", 149 "add this directory", "add this symlink" and so on. 150 151 This could clean up tar and zip, and make it cheaper to add cpio and ar 152 write support, and possibly even cheaply add things like mkisofs or 153 mksquashfs someday, if they become relevant. 154--- 155Text buffer support. 156 Several existing applets (sort, vi, less...) read 157 a whole file into memory and act on it. Use open_read_close(). 158--- 159Memory Allocation 160 We have a CONFIG_BUFFER mechanism that lets us select whether to do memory 161 allocation on the stack or the heap. Unfortunately, we're not using it much. 162 We need to audit our memory allocations and turn a lot of malloc/free calls 163 into RESERVE_CONFIG_BUFFER/RELEASE_CONFIG_BUFFER. 164 For a start, see e.g. make EXTRA_CFLAGS=-Wlarger-than-64 165 166 And while we're at it, many of the CONFIG_FEATURE_CLEAN_UP #ifdefs will be 167 optimized out by the compiler in the stack allocation case (since there's no 168 free for an alloca()), and this means that various cleanup loops that just 169 call free might also be optimized out by the compiler if written right, so 170 we can yank those #ifdefs too, and generally clean up the code. 171--- 172FEATURE_CLEAN_UP 173 This is more an unresolved issue than a to-do item. More thought is needed. 174 175 Normally we rely on exit() to free memory, close files and unmap segments 176 for us. This makes most calls to free(), close(), and unmap() optional in 177 busybox applets that don't intend to run for very long, and optional stuff 178 can be omitted to save size. 179 180 The idea was raised that we could simulate fork/exit with setjmp/longjmp 181 for _really_ brainless embedded systems, or speed up the standalone shell 182 by not forking. Doing so would require a reliable FEATURE_CLEAN_UP. 183 Unfortunately, this isn't as easy as it sounds. 184 185 The problem is, lots of things exit(), sometimes unexpectedly (xmalloc()) 186 and sometimes reliably (bb_perror_msg_and_die() or show_usage()). This 187 jumps out of the normal flow control and bypasses any cleanup code we 188 put at the end of our applets. 189 190 It's possible to add hooks to libbb functions like xmalloc() and xopen() 191 to add their entries to a linked list, which could be traversed and 192 freed/closed automatically. (This would need to be able to free just the 193 entries after a checkpoint to be usable for a forkless standalone shell. 194 You don't want to free the shell's own resources.) 195 196 Right now, FEATURE_CLEAN_UP is more or less a debugging aid, to make things 197 like valgrind happy. It's also documentation of _what_ we're trusting 198 exit() to clean up for us. But new infrastructure to auto-free stuff would 199 render the existing FEATURE_CLEAN_UP code redundant. 200 201 For right now, exit() handles it just fine. 202 203 204Minor stuff: 205 watchdog.c could autodetect the timer duration via: 206 if(!ioctl (fd, WDIOC_GETTIMEOUT, &tmo)) timer_duration = 1 + (tmo / 2); 207 Unfortunately, that needs linux/watchdog.h and that contains unfiltered 208 kernel types on some distros, which breaks the build. 209--- 210 use bb_error_msg where appropriate: See 211 egrep "(printf.*\([[:space:]]*(stderr|2)|[^_]write.*\([[:space:]]*(stderr|2))" 212--- 213 use bb_perror_msg where appropriate: See 214 egrep "[^_]perror" 215--- 216 possible code duplication ingroup() and is_a_group_member() 217--- 218 Move __get_hz() to a better place and (re)use it in route.c, ash.c 219--- 220 See grep -r strtod 221 Alot of duplication that wants cleanup. 222--- 223 unify progress_meter. wget, flash_eraseall, pipe_progress, fbsplash, setfiles. 224--- 225 support start-stop-daemon -d <chdir-path> 226--- 227 228(TODO list after discussion 11.05.2009) 229 230* shrink tc/brctl/ip 231 tc/brctl seem like fairly large things to try and tackle in your timeframe, 232 and i think people have posted attempts in the past. Adding additional 233 options to ip though seems reasonable. 234 235* add tests for some applets 236 237* implement POSIX utilities and audit them for POSIX conformance. then 238 audit them for GNU conformance. then document all your findings in a new 239 doc/conformance.txt file while perhaps implementing some of the missing 240 features. 241 you can find the latest POSIX documentation (1003.1-2008) here: 242 http://www.opengroup.org/onlinepubs/9699919799/ 243 and the complete list of all utilities that POSIX covers: 244 http://www.opengroup.org/onlinepubs/9699919799/idx/utilities.html 245 The first step would to generate a file/matrix what is already archived 246 (also IPV6) 247 248* implement 'at' 249 250* rpcbind (former portmap) or equivalent 251 so that we don't have to use -o nolock on nfs mounts 252 253* check IPV6 compliance 254 255* generate a mini example using kernel+busybox only (+libc) for example 256 257* more support for advanced linux 2.6.x features, see: iotop 258 most likely there is more 259