1<html><head><title>toybox cleanup</title></head>
   2<!--#include file="header.html" -->
   7<li><a href=#intro>Introduction</a></li>
   8<li><a href=#advice>Advice</a></li>
  11<li><a href=#uuencode>uuencode</a></li>
  12<li><a href=#uudecode>uudecode</a></li>
  13<li><a href=#ifconfig>ifconfig</a></li>
  14<li><a href=#stat>stat</a></li>
  20<a name=intro />
  21<h1>Cleaning up the toybox code.</h1>
  23<p>Toybox <a href=>hasn't always</a>
  24taken proper advantage of external contributions</a>.
  25Lots of people want to help, but their contributions languish out of tree
  26or in the "pending" directory, awaiting cleanup.</p>
  28<p>Toybox's design goals require simpler, tighter, and more explicit code
  29than most other implementations, among other reasons to allow better security
  30auditing. Writing "another" implementation of standard command line tools
  31isn't very interesting, they should be _better_ implementations.
  32Unfortunately, this means existing, working commands often take more effort to
  33clean up to Toybox's standards than writing a new one from scratch, not
  34because they don't work, but because we aim for an unusual level of polish.</p>
  36<p>In hopes of teaching more people how to do this
  37cleanup work, I've started breaking cleanup changes into smaller chunks and
  38posting explanations of each change to the mailing list.
  39Below are indexes of such cleanup series. Each commit and post are meant to
  40be read together: each description explains what the corresponding patch
  41was trying to accomplish.</p>
  43<p>Line/byte totals of completed series are given for scale, but the point
  44of this work is simplicity and compactness, not size per se.</p>
  46<p>(Note: mercurial's web viewer doesn't follow renames, so although each
  47command name links to a commit list with the bulk of the changes, it may
  48not include the final version of each file moved from the "pending"
  49directory to its final location. The summaries link the initial and cleaned
  50versions of each file when giving line counts.)</p>
  54<a name=advice />
  55<h1>General advice and/or policy.</h1>
  57<p>The <a href=design.html>design of toybox</a> page and the coding
  58style section at the start of the <a href=code.html>source code walkthrough</a>
  59don't cover everything. Here are some
  60links to mailing list messages that cover various programming topics
  61not directly related to a specific cleanup series:</p>
  64<li><a href=>Error messages and internationalization.</a></li>
  65<li><a href=>Why not "const"?</a> (Exception: global variables
  66outside of GLOBALS can be static const, to go in rodata instead of data.
  67This means the pages can be shared between instances.)</li>
  68<li><a href=>Why not "bool"?</a> (explanation from Linus Torvalds)</li>
  69<li><a href=>Why not to check in debug code.</a></li>
  70<li><a href=>Relationship between /proc and /sys</a> (/proc isn't obsolete and /sys is an ABI)</li>
  71<li>"Hiding numbers that are used just once into defines to put them out of
  72sight does not really help readability."</a> -
  73<a href=>Pavel
  75<li>"Infrastructure in search of a user" is a bad thing, so don't put code
  76in lib/ that doesn't already have at least two users. Don't preemptively
  77factor stuff out, it's easy enough to rewrite it uin future if it needs
  78to change. The "extreme programming" fad called this "You Ain't Gonna
  79Need It" (while inexplicably screaming at cans of Mountain Dew, back in the
  8090's). Here's <a href=>Linus Torvalds' take</a>.</li>
  85<a name="uuencode"><h1><a href=/hg/toybox/log/900/toys/pending/uuencode.c>uuencode</a></h1>
  87<p>This is an example of cleaning up something most projects would be quite
  88happy with. The initial submission of uuencode and uudecode was high
  89quality code, written by a seasoned developer who did an excellent
  90job, but it was still possible to shrink the result almost by half:</p>
  93<li>old total: <a href=/hg/toybox/file/828/toys/pending/uuencode.c>116 lines (2743
  94bytes) in 7 functions</a></li>
  95<li>new total: <a href=/hg/toybox/file/841/toys/posix/uuencode.c>67 lines (1440
  96bytes) in 1 function</a></li>
 100<li>commit: <a href=/hg/toybox/rev/830>830</a>: first pass, description: <a href=>part 1</a>,
 101<a href=>part 2</a></li>
 102<li>commit: <a href=/hg/toybox/rev/831>831</a>,
 103second pass, description: <a href=>part 3</a></li>
 104<li>commit: <a href=/hg/toybox/rev/837>837</a>,
 105description: fix test suite.</li>
 106<li>commit: <a href=/hg/toybox/rev/853>853</a>, description: bugfix.</li>
 109<p>Status: COMPLETE</p>
 111<a name="uudecode"><h1><a href=/hg/toybox/log/900/toys/pending/uudecode.c>uudecode</a></h1>
 113<p>The uudecode cleanup was my second "explain as I go along" cleanup,
 114and I tried to do it in smaller stages so it was easier to see what
 115changed from the diff:</p>
 118<li>old: <a href=/hg/toybox/file/828/toys/pending/uudecode.c>175
 119lines (4534 bytes) in 9 functions</a></li>
 120<li>new: <a href=/hg/toybox/file/840/toys/posix/uudecode.c>107 lines
 121(2300 bytes) in 1 function</a></li>
 125<li>commit: <a href=/hg/toybox/rev/833>833</a>,
 126description: preparatory adjustments to test suite.</li>
 127<li>commit: <a href=/hg/toybox/rev/835>835</a>,
 128description: <a href=>Redo command line parsing, redo parsing loop.</a></li>
 129<li>commit: <a href=/hg/toybox/rev/838>838</a>,
 130description: <a href=>Redo b64_1byte, b64_4bytes, and uu_line()</a></li>
 131<li>commit: <a href=/hg/toybox/rev/839>839</a>,
 132description: todo</a></li>
 133<li>commit: <a href=/hg/toybox/rev/840>840</a>,
 134description: todo (finish, move pending->posix, default y)</a></li>
 137<p>Status: COMPLETE</p>
 139<a name=ifconfig>
 140<h1><a href=/hg/toybox/log/tip/toys/pending/ifconfig.c>ifconfig</a></h1>
 142<p>This series describes a thorough cleanup that took a while to do.</p>
 144<p>When ifconfig was submitted, it touched a half-dozen files. I glued it
 145together into a single self-contained file, which needed a lot of
 146cleanup. The final version is about 1/3 the size of the original.</p>
 149<li>old total: <a href=/hg/toybox/file/841/toys/pending/ifconfig.c>1504 lines (44268 bytes) in 38 functions</a></li>
 150<li>new total: <a href=/hg/toybox/file/1133/toys/other/ifconfig.c>521 lines (15963 bytes) in 4 functions</a></li>
 153<p>This was the first command I started cleaning up with the intent of
 154describing the process, and especially the first few entries in this
 155series describe many of the low hanging fruit techniques used to clean
 156up a codebase.</p>
 159<li>commit: <a href=/hg/toybox/rev/843>843</a>, description: <a href=>Infrastructure in search of a user, code proximity,
 160unnecessary #defines, shorter code is easier to read.</a></li>
 161<li>commit: <a href=/hg/toybox/rev/844>844</a>,
 162description: <a href=>Headers, replacing repeated code with loops,
 163logical operators guaranteed to return 0 or 1, math on string constants,
 164removing unnecessary variables and tests.</a></li>
 165<li>commit: <a href=/hg/toybox/rev/852>852</a>,
 166description: <a href=>hg commit numbers, documenting the obvious, ordering
 167to avoid prototypes, returning void, collate local declarations,
 168use error_exit(), unnecessary parentheses, inline to remove variables/functions
 169used only once, using *var instead of var[0], unnecessary typecasts,
 170xprintf("\n") vs xputc('\n')</a></li>
 171<li>commit: <a href=/hg/toybox/rev/856>856</a>,
 172description: one line portability fix from Isaac Dunham</li>
 173<li>commit: <a href=/hg/toybox/rev/861>861</a>
 174and <a href=/hg/toybox/rev/863>863</a>,
 176<a href=>Help
 177infrastructure cleanup from Isaac Dunham</a>
 178(which I mis-applied and then <a href=>fixed plus some whitespace changes</a>)</li>
 180<li>commit: <a href=/hg/toybox/rev/862>862</a>, description:
 181<a href=>remove unused headers and function, replace local buffer with toybuf, perror_exit(), avoid unnecessary assignment.</a></li>
 182<li>commit: <a href=/hg/toybox/rev/864>864</a>, description:
 183<a href=>use common linked list functions, inline set_data, add xioctl, clean up error messages, whitespace and comment tweaks, remove NOP return statements</a></li>
 184<li>commit: <a href=/hg/toybox/rev/866>866</a>, description:
 185<a href=>move standalone globals into GLOBALS() block, collate structs into
 186iface_list. Inline/rewrite/remove field_format, iface_flags_str,
 187omit_whitespace(), print_iface_flags(), print_media(), get_ifconfig_info(),
 188and clear_list(). Merge duplicate function
 189calls. Show get_proc_info() version field can't matter in 2.6 or newer kernel,
 190and that SIOCGIFMAP has been there since 1994 so doesn't need an #ifdef.
 191Loop simplification in readconf() and show_iface().</a></li>
 193<li>commit: <a href=/hg/toybox/rev/869>869</a> and <a href=/hg/toybox/rev/870>870</a>,
 194description: <a href=>869:
 195reorder to eliminate prototypes, put command_main() at end of file,
 196870: long repeated variable prefixes, replacing struct+sscanf()+printf with a
 197loop and a table (from iface_list, get_proc_info(), display_ifconfig()),
 198use lib/xwrap.c functions to return void, why xstrcpy() fails closed,
 199(functional comment: why multicast failed, CSLIP obsolecense), not being
 200_too_ clever.</a></li>
 201<li>commit: <a href=/hg/toybox/rev/878>878</a> and <a href=/hg/toybox/rev/879>879</a>:
 202description: <a href=>878: add xsocket(), free(NULL) is a safe NOP (posix!).
 203879: inline three functions and simplify, some simplifications only show up
 204after repeated inlining</a></li>
 205<li>commit: <a href=/hg/toybox/rev/883>883</a>,
 206description: move some common code to lib/ and posix headers to toys.h.</li>
 207<li>commit: <a href=/hg/toybox/rev/898>898</a>,
 208description: <a href=>Argument parsing. (Replace ifconfig_main() if/else staircase with a loop over
 209an array, genericize minus prefix logic, inline a use of set_flags().)</a></li>
 210<li>commit: <a href=/hg/toybox/rev/905>905</a>,
 211description: <a href=>remove unnecessary wrapper function, inlining more functions,
 212relying on the values of constants that don't change across architectures
 213(binary backwards compatability), more ifconfig_main table work,
 214man ioctl_list.</a></li>
 215<li>commit: <a href=/hg/toybox/rev/906>906</a>,
 216description: <a href=>More ifconfig_main() table work, remove vestigial arguments
 217to functions, "a frenzy of inlining", slightly better error reporting,
 218don't reinvent libc functions.</a></li>
 219<li>commit: <a href=/hg/toybox/rev/907>907</a>,
 220<a href=>inlining show_ip_addr() with a loop and a table, inlining hex_to_binary()
 221and set_hw_address(), stop validating data we supplied, remove a table
 222that's overkill (two entries, we don't even loop over it), when you don't need a
 223NULL terminator for array, remove unnecessary memcpy(offsetof()) with
 224assignment, trusting -funsigned-char.</a></li>
 225<li>commit: <a href=/hg/toybox/rev/919>919</a>,
 226<a href=>todo whitespace damage, introduce IFREQ_OFFSZ() and poke() to
 227ifconfig_main() table logic to fold more if/else parts into the table</a></li>
 228<li>Status update: <a href=>Entering the home stretch on ifconfig</a> (and a <a href=>note about infiniband</a>)</li>
 229<li>commit: <a href=/hg/toybox/rev/921>921</a>, description: <a href=>Inline a couple more functions and make sockfd a global.</li>
 230<li>commit: <a href=/hg/toybox/rev/957>957</a>, description: <a href=>Remove unused socklen and addr_to_len(), cleanup so we can merge get_device_info()/display_ifconfig().</a></li>
 231<li>commit: <a href=/hg/toybox/rev/958>958</a>, description: <a href=>This commit removes struct if_list by unifying get_device_info() and display_ifconfig().</a></li>
 232<li>commit: <a href=/hg/toybox/rev/1104>1104</a>, description: Merge toynet into toys.h: musl supports it and micromanaging uClibc config options isn't very interesting anymore.</li>
 233<li>commit: <a href=/hg/toybox/rev/1127>1127</a>, description: <a href=>Start tacling ipv6 issues, beginning with display_ifconfig().</a></li>
 234<li>commit: <a href=/hg/toybox/rev/1128>1128</a>, description: <a href=>More ipv6, make struct sockaddr_with_len go away, merge more arguments into the table in main().</a></li>
 235<li>commit: <a href=/hg/toybox/rev/1132>1132</a>, description: promotion from pending to other</li>
 236<li>commit: <a href=/hg/toybox/rev/1133>1133</a>, description: <a href=>cleanup help text, remove obsolete/NOP commands</a></li>
 239<p>Status: COMPLETE.</p>
 241<p>Status: in progress.</p>
 243<a name=stat>
 244<h1><a href=/hg/toybox/log/917/toys/pending/stat.c>stat</a></h1>
 246<p>A lot of the stat cleanup was done by Felix Janda.</p>
 249<li>commit <a href=/hg/toybox/rev/747>747</a>: initial submission</a></li>
 250<li>commit <a href=/hg/toybox/rev/810>810</a>: whitespace</li>
 251<li>commit <a href=/hg/toybox/rev/811>811</a>: description in commit message.</li>
 252<li>commit <a href=/hg/toybox/rev/871>871</a>: whitespace (reindent from 4 spaces to 2)</li>
 253<li>commit <a href=/hg/toybox/rev/872>872</a>: Felix Janda - <a href=>cleanup</a> (with discussion thread)</li>
 254<li>commit <a href=/hg/toybox/rev/875>885</a>: Felix Janda - <a href=>move permission formatting (777 -> -rwxrwxrwx) from ls to lib so stat can reuse it.</a></li>
 255<li>commit <a href=/hg/toybox/rev/885>886</a>: Felix Janda - remove unimplemented options and clean up help text</li>
 256<li>commit <a href=/hg/toybox/rev/910>910</a>: Felix Janda - <a href=>Add support for stating multiple files</a>.</li>
 257<li>commit <a href=/hg/toybox/rev/911>911</a>: Felix Janda - Separate stat and statfs, give stat_main() a ds[2] array to distinguish FLAG_f vs not cases, and some whitespace changes.</li>
 258<li>commit <a href=/hg/toybox/rev/912>912</a>: description in commit message (also <a href=>here</a>)</li>
 259<li><a href=>design pondering</a> (leading to peek() function in lib/)</li>
 261<li>commit <a href=/hg/toybox/rev/914>914</a>: description in commit message.</li>
 262<li>commit <a href=/hg/toybox/rev/916>916</a>: description in commit message.</li>
 263<li>commit: <a href=/hg/toybox/rev/917>917</a>: description in commit message.</li>
 264<li>commit: <a href=/hg/toybox/rev/918>918</a>,
 265description: done: move pending to posix, default y, no other changes</a>.</li>
 266<li><a href=>summary</a></li>
 269<p>Status: COMPLETE.</p>
 271<!--#include file="footer.html" -->