mingw.c: add missing break in fcntl implementation

This may address:

   https://github.com/rmyorston/busybox-w32/issues/25
mingw.c: ignore EACCES from mkdir if directory exists

Microsoft Windows has a strange issue with access permissions such that
mkdir will sometimes return EACESS for an existing directory.  This is
mentioned here:

   http://www.apijunkie.com/APIJunkie/blog/post/2009/12/22/_mkdir-C-runtime-library-function-might-return-unexpected-error-values.aspx

This was causing mkdir -p to fail on a particular machine.  Ignoring the
EACCES error if the directory exists fixes the problem.
udhcpd: add option for tweaking arpping

Some clients have a very short timeout for sending the DHCP
DISCOVER, shorter than the arpping timeout of 2000 milliseconds
that udhcpd uses by default.

This patch allows tweaking the timeout, or disabling of arpping
altogether, at the risk of handing out addresses which are
already in use.

function                                             old     new   delta
udhcpd_main                                         1460    1501     +41
udhcpc_main                                         2814    2851     +37
packed_usage                                       29957   29974     +17
arpping                                              477     493     +16
find_free_or_expired_nip                             161     174     +13
send_offer                                           285     292      +7
nobody_responds_to_arp                                85      89      +4
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 7/0 up/down: 135/0)             Total: 135 bytes

Signed-off-by: Michel Stam <m.stam@fugro.nl>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
zcip: allow our own class B range to be used for ZeroConf

169.254 may already be used by a local network. This patch allows
specifying your own IP range.

Our particular use case is a mesh network, in which the nodes partaking
were using an IP range specifically assigned for the meshing purpose.
As the LAN side of the mesh node could use 169.254, this default range
was not an option.

function                                             old     new   delta
zcip_main                                           1342    1426     +84
pick_nip                                               -      40     +40
packed_usage                                       29974   29969      -5
pick                                                  34       -     -34
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 1/1 up/down: 124/-39)            Total: 85 bytes

Signed-off-by: Michel Stam <m.stam@fugro.nl>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
zcip: Add environment variable for overriding log functionality

function                                             old     new   delta
bb_logenv_override                                     -      70     +70
packed_usage                                       29969   30033     +64
zcip_main                                           1426    1431      +5
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 2/0 up/down: 139/0)             Total: 139 bytes

Signed-off-by: Michel Stam <m.stam@fugro.nl>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
exit with 127 if appled name wasn't found - it's more POSIXy

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
iproute: support onelink route option and print route flags

function                                             old     new   delta
print_route                                         1797    1865     +68
do_iproute                                          2097    2112     +15
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 83/0)               Total: 83 bytes

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
ash: fix handling of negative start value in ${v:start:len}

function                                             old     new   delta
subevalvar                                          1140    1168     +28

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
ash,hush: do not segfault on $((2**63 / -1))

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
typo fix in comment

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
modprobe,rmmod: reject module names with slashes

function                                             old     new   delta
add_probe                                             86     113     +27

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
init: do not run shutdown/reexec actions from signal handler

this is racy wrt various libc functions such as syslog()

function                                             old     new   delta
check_delayed_sigs                                   182     352    +170
init_main                                            772     728     -44
restart_handler                                       74       -     -74
halt_reboot_pwoff                                     79       -     -79
------------------------------------------------------------------------------
(add/remove: 0/2 grow/shrink: 1/1 up/down: 170/-197)          Total: -27 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Use putenv to implement unsetenv/clearenv

noexec applets failed on ReactOS 0.3.17.  This was because the
environment was being manipulated directly using the environ pointer.
Implementing unsetenv and clearenv using putenv fixes the problem.

WIN32 putenv doesn't allow environment variables to have empty
values.  This was the case before and it's still the case after
this change.  Shell variables are fine.
udhcpd: if a lease from lease file coincides with a static one, ignore it

function                                             old     new   delta
read_leases                                          269     328     +59

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
gitignore: add testsuite/echo-ne

Signed-off-by: Bartosz Golaszewski <bartekgola at gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
bbunit: fix WANT_TIMING compilation

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
libbb: use ARG_MAX for bb_arg_max() only if it's 60k+

Sometimes ARG_MAX is small (like 32k) yet sysconf(_SC_ARG_MAX)
is big, and people prefer using the bigger value.

OTOH, with sufficiently large ARG_MAX, further wins from
sysconf(_SC_ARG_MAX) being bigger are exponentially smaller:
you can see 4 times fewer fork+execs when you run find, but
when each execed process already takes a thousand parameters
it's likely execution time is dominated by what that process
does with each parameter.

Thus, with this change ARG_MAX is used if it's sufficiently big,
otherwise sysconf(_SC_ARG_MAX) is used.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
man: accept a list of dirs in $MANPATH

function                                             old     new   delta
add_MANPATH                                            -     143    +143
man_main                                             852     731    -121
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/1 up/down: 143/-121)           Total: 22 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
libbb: use sendfile() to copy data between file descriptors

Busybox already uses sendfile in httpd. This patch proposes to use it
globally to copy data between file descriptors.

It speeds up the copying on slow systems a lot - below are the times needed
to copy a 450Mb file with and without this option enabled on a BeagleBone
Black:

sendfile:
user    0m0.000s
sys     0m8.170s

read/write 4k:
user    0m0.470s
sys     0m16.300s

function                                             old     new   delta
bb_full_fd_action                                    394     474     +80

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Move definition of bb_got_signal to mingw.c

On POSIX platforms bb_got_signal is defined in libbb/signals.c; for
MinGW put the definition in win32/mingw.c.  This is better than the