ash: add/improve comments, no code changes

ash: fix $IFS handling in read. closes bug 235

hush: fix wait builtin

function                                             old     new   delta
builtin_wait                                         174     275    +101
sigwaitinfo                                            -      48     +48
__GI_sigwaitinfo                                       -      48     +48
check_and_run_traps                                  133     169     +36
checkjobs                                            349     380     +31
hush_main                                            971     991     +20
static.zero_timespec                                   -       8      +8
run_list                                            2010    2016      +6
file_get                                             254     260      +6
static.zero_ts                                         8       -      -8
------------------------------------------------------------------------------
(add/remove: 3/1 grow/shrink: 6/0 up/down: 304/-8)            Total: 296 bytes

libbb: fix typo in comment

hush: don't lie in comment

hush: fix comments, no code changes

hush: make ^C work again, ^Z probably isn't working

function                                             old     new   delta
file_get                                             219     254     +35
check_and_run_traps                                  122     133     +11
run_list                                            2001    2010      +9
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/0 up/down: 55/0)               Total: 55 bytes

hush: do not reset sighaldlers after fork - instead, prevent them from doing any harm
 if they will be called. saves many sigaction calls on every fork.

function                                             old     new   delta
hush_main                                            887     971     +84
sigexit                                               54      65     +11
run_list                                            2006    2001      -5
maybe_set_sighandler                                  76      50     -26
set_fatal_sighandler                                 186       -    -186
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 2/2 up/down: 95/-217)          Total: -122 bytes

hush: rework signal and trap handling. Some smaller bits are TODO,
 expect minor breakage

function                                             old     new   delta
set_fatal_sighandler                                  12     186    +174
check_and_run_traps                                    -     122    +122
maybe_set_sighandler                                   -      76     +76
hush_main                                            831     887     +56
sigtimedwait                                           -      50     +50
__GI_sigtimedwait                                      -      50     +50
hush_exit                                             49      93     +44
set_mode                                             749     777     +28
pseudo_exec_argv                                     131     151     +20
static.zero_ts                                         -       8      +8
expand_variables                                    1962    1970      +8
builtin_wait                                         172     174      +2
set_misc_sighandler                                   12       -     -12
set_jobctrl_sighandler                                12       -     -12
handler_ctrl_c                                        16       -     -16
builtin_set_mode                                      28       -     -28
handle_trap                                           97       -     -97
handler_ctrl_z                                       107       -    -107
builtin_trap                                         545     438    -107
run_list                                            2149    2006    -143
------------------------------------------------------------------------------
(add/remove: 5/6 grow/shrink: 7/2 up/down: 638/-522)          Total: 116 bytes

implement `unset` semantics as required by POSIX

fix DOC build output to be like kbuild standard

update `trap` poisx link

do not automatically display job information when the shell is not interactive

enable trap tests

first pass at `trap` support in hush

modutils: dont pass NULL options to init_module()

build system: hdparm -d is not that dangerous, remove warning

sendmail: add more example in usage text

module loading for 2.4: use fd-based io instead of FILE based;
 use xlseek and xread; simpler check for ELF signature.

   text    data     bss     dec     hex filename
 824460     476    7616  832552   cb428 busybox_old
 824333     476    7616  832425   cb3a9 busybox_unstripped

add test cases for `trap` ... but disabled for now until trap support is committed

sysctl: move code around to get rid of forward references.
 (incidentally it helps gcc to make code smaller)

sysctl: fix broken -p [file] - close bug 231

mark msh as deprecated

use bb_strtou() in umask/wait and check errno to see if there was a problem rather than using endp

make sure we check job status whenever updating the prompt

test for invalid named variables

do not let handle_dollar() accept vars that start with a digit

implement `wait` builtin

remove ((expr)) bash'ism

randomconfig fix

update the normally disabled debug code around the syntax() func to use new maybe_die()

randomtest fixes

add hush tests for parameter expansion

implement most POSIX parameter expansions (~+500bytes)

make sure we exit based on test failure rather than always exiting with 0

split up feature todo by posix/bash

unify `set` handling with command line processing, fixup `set` argv processing so it doesnt clobber argv when setting options, and barf on unhandled set options

handle the "-s" command line option that POSIX requires

rename "-f" (fake) option to "-n" to match POSIX

tweak format modifier in debug code to fixup gcc warning

convert some of the ENABLE_FEATURE_EDITING from CPP if to C if

stop lying about [[ test support

mkfs.vfat: fix a problem with over-estimating FAT size

make lash deprecation more prominent

mkfs.vfat: mkdosfs compat with choosing clyster size

mkfs.vfat: more of pointless tweaking

mkfs.vfat: small tweak to comments

mkdosfs (aka mkfs.vfat): new applet by Vladimir

   text    data     bss     dec     hex filename
 821202     476    7616  829294   ca76e busybox_old
 823577     476    7616  831669   cb0b5 busybox_unstripped

ls: warning fix
rm: accept and ignore -v (verbose)

tail: fix tail +N syntax not working. Closes bug 221.

enable most job functions on no-mmu systems

tftp: when we infer local name from remote (-r [/]path/path/file),
 strip path. This mimics wget and is generally more intuitive.

do not make startup banner depend on job support

libbb: revent previous version of "concurrent history updating"
and replace it with one which does not "snoop" history written
by others. (1) it is what bug 185 needs, and (2) it is less bloaty:

function                                             old     new   delta
load_history                                           -     252    +252
read_line_input                                     3155    3287    +132
next_token                                           914     918      +4
qrealloc                                              36      33      -3
getoptscmd                                           713     708      -5
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 2/2 up/down: 388/-8)            Total: 380 bytes

move parse_stream out of ENABLE_HUSH_TICK to avoid implicit decl/build error

libbb: make history saving/loading concurrent-safe
* all history writers always append (not overwrite) history files
* they reload history if they detect that file length has changed since last
write
* they trim history file only when it grows 4 times longer than MAXLINES
* they do this atomically by creating new file and renaming it to old

Unfortunately, this comes at a price:

function                                             old     new   delta
load_history                                           -     346    +346
read_line_input                                     3155    3358    +203
new_line_input_t                                      17      31     +14
...irrelevant small jitter...
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 5/5 up/down: 573/-13)           Total: 560 bytes

timeout: fix parsing of -t NUM on MMU

hush: rearrange functions to reduce amount of forward references.
 Minimal code changes.

hush: fix segv at repeated "set -- a b c" + "shift"

hush: fix strcpy of potentially overlapping strings

msh testsuite: fix false positive, tweak run stript

ls: make readlink error to not disrupt output (try ls -l /proc/self/fd).
libbb: make xmalloc_readlink_or_warn warning more specific.

function                                             old     new   delta
xmalloc_readlink_or_warn                              33      61     +28
showfiles                                           1495    1460     -35
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 28/-35)             Total: -7 bytes

cpio: more compat: -0 and -L options

function                                             old     new   delta
cpio_main                                           1417    1473     +56

Compatibility fixes:

grep: support -z
find: support --mindepth
  together +45 bytes
cpio: support -p (configurable, +230 bytes)
libbb: tweaks for cpio

cd: "support" -v by ignoring it

hush: tweak testsuite

hush: fix bug 207 and "hush -c" parameter passing.
 Now hush -c 'printf "%s\n" "$@"' (prints "\n")
 and hush -c 'printf "%s\n" "$@"' qwe asd (prints "asd\n")
 both work correctly

ash: expand comment

hush: fix set [--] params. Closes bug 199.

function                                             old     new   delta
builtin_set                                           55     194    +139
add_strings_to_strings                                 -     130    +130
add_string_to_strings                                110      26     -84
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/1 up/down: 269/-84)           Total: 185 bytes

ash: add missing comma in debug scaffolding

ash: fix a case where we close wrong descriptor; add debug hack for that

ash: DEBUG should be 0 :)

ash: fix TRACE commands

ash: make evaltree save/restore int suppression depth.
 Hopefully this fixes bug 189. Not confirmed by users yet.

function                                             old     new   delta
evaltree                                             809     842     +33
evalvar                                             1374    1376      +2

doc update

ash: in dotrap(), do not clear gotsig[] for SIGINT if there is no handler
 for it, otherwise raise interrupt gets confused later.
 The rest are readability fixes.

function                                             old     new   delta
evaltreenr                                           817     818      +1
evaltree                                             817     818      +1
evalstring                                            88      89      +1
cmdloop                                              420     419      -1
evalskip                                               4       1      -3
breakcmd                                              84      81      -3
ash_main                                            1382    1379      -3
evalloop                                             183     177      -6
evalfor                                              231     225      -6
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/6 up/down: 3/-22)             Total: -19 bytes

df: fix FEATURE_DF_FANCY=off, FEATURE_HUMAN_READABLE=on case.

ash: tentatively fix bug 189.

init: test for vt terminal with VT_OPENQRY,
 assume that anything else is TERM=vt102, not TERM=linux.
 (Serial console test is less correct)
 Tentatively closes bug 195.

function                                             old     new   delta
init_main                                            946     919     -27

ash: fix "ash -c 'exec 1>&0'" complaining that fd 0 is busy

ls: make color-related code more readable. Fix a case when
 it was working non-deterministically.

function                                             old     new   delta
bold                                                   -      34     +34
showfiles                                           1508    1495     -13
fgcolor                                               50      34     -16
bgcolor                                               34       -     -34
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 0/2 up/down: 34/-63)            Total: -29 bytes

httpd: add comment explaining why SERVER_NAME etc is not set.

ftpd: fix command fetching to not do it in 1-byte reads;
 fix command de-escaping. Tested to download files with embeeded \xff and LF.
libbb: tweaks for the above

function                                             old     new   delta
ftpd_main                                           2231    2321     +90
xmalloc_fgets_internal                               190     222     +32
xmalloc_fgets_str_len                                  -      27     +27
xmalloc_fgets_str                                      7      23     +16
xmalloc_fgetline_str                                  10      26     +16
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 4/0 up/down: 181/0)             Total: 181 bytes

ftpd: add some comments

ftpd: trim messages (but make sure they still make sense)
   text    data     bss     dec     hex filename
   4400       0       0    4400    1130 ftpd_old.o
   4346       0       0    4346    10fa ftpd.o

ftpd: do not use nasty tricks for re-execing if we are on MMU machine.
On NOMMU, code is alomost the same, on MMU:

function                                             old     new   delta
handle_dir_common                                    223     390    +167
ftpd_main                                           2306    2231     -75
popen_ls                                             203       -    -203
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 1/1 up/down: 167/-278)         Total: -111 bytes

ftpd: add support for MDTM, I see clients often use it,
 it may allow client-side caching.

function                                             old     new   delta
ftpd_main                                           2232    2306     +74
gmtime_r                                               -      19     +19
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/0 up/down: 93/0)               Total: 93 bytes

ftpd: document NLST format

ftpd: instead of wordy HELP, implement useful, and smaller, FEAT.
 (HELP is still "supported" as an alias to FEAT)

   text    data     bss     dec     hex filename
 807331     468    7856  815655   c7227 busybox_old
 807246     468    7856  815570   c71d2 busybox_unstripped

ftpd: implement -vv verbosity

function                                             old     new   delta
ftpd_main                                           2097    2190     +93
verbose_log                                            -      33     +33
cmdio_write_raw                                       12      34     +22
cmdio_write_ok                                        25      45     +20
cmdio_write_error                                     25      45     +20
cmdio_write                                           62      78     +16
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 5/0 up/down: 204/0)             Total: 204 bytes

ftpd: tweak timeout code

chat: update by Vladimir
 1) to treat timeout more correctly (timeout affects whole send command
    duration, not a single char);
 2) to recognize RECORD directive.

function                                             old     new   delta
chat_main                                           1246    1359    +113
exitcode                                               1       -      -1

ftpd: fix thinko: set_nport takes port in network order

ftpd: dont use fdprintf for simple status messages

function                                             old     new   delta
ftpd_main                                           2025    2055     +30
cmdio_write_ok                                        17      25      +8
cmdio_write_error                                     17      25      +8
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/0 up/down: 46/0)               Total: 46 bytes

ftpd: simplify PORT check by assuming IP = peer's IP.
 Should be as safe as before this change.

function                                             old     new   delta
ftpd_main                                           2115    2025     -90

ftpd: add idle and absolute timeouts. This is a security issue,
 otherwise ftpd may end up hanging indefinitely.

function                                             old     new   delta
timeout_handler                                        -     110    +110
ftpd_main                                           2019    2115     +96
packed_usage                                       25662   25685     +23
handle_upload_common                                 306     322     +16
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 3/0 up/down: 245/0)             Total: 245 bytes

ftpd: security tightened up:
 PORT is not allowed on !IPv4
 PORT must have IP == peer's IP
 upload is allowed only into regular files

function                                             old     new   delta
ftpd_main                                           1815    2019    +204
handle_upload_common                                 260     306     +46
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 250/0)             Total: 250 bytes

awk: fix compat issue found by gpm build

function                                             old     new   delta
as_regex                                             105     131     +26
hash_find                                            247     233     -14
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 1/1 up/down: 26/-14)             Total: 12 bytes

tr: support -C as synonym to -c

ftpd: fix the bug where >2GB file ops report errors;
 make a few simplifications; add TODOs.

function                                             old     new   delta
port_or_pasv_was_seen                                  -      37     +37
get_remote_transfer_fd                               104     109      +5
handle_upload_common                                 265     260      -5
handle_dir_common                                    228     223      -5
popen_ls                                             211     203      -8
ftpd_main                                           1825    1815     -10
data_transfer_checks_ok                               37       -     -37
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 1/4 up/down: 42/-65)            Total: -23 bytes