logread: flush output. closes 6710

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

awk: fix a bug in argc counting in recent change

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

rfkill: use new-style config/kbuild/applet

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

tar: prevent empty file to be treated as valid tarball

function                                             old     new   delta
tar_main                                             879     895     +16

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

fix a copy/paste error in last tar testcase name

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

tar: add a testcase for previous commit

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

tar: fix exitcode check for MMU-spawned unpacking helpers

Testcase: tar xvzf EMPTY_FILE

function                                             old     new   delta
open_transformer                                     102     106      +4
get_header_tar                                      1781    1785      +4

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

libbb: move nuke_str() from passwd into libbb

function                                             old     new   delta
nuke_str                                               -      15     +15
ask_and_check_password_extended                      215     206      -9
init_main                                            781     771     -10
nuke_str                                              27       -     -27
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 0/2 up/down: 15/-46)            Total: -31 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

comment tweak

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

sulogin: use common password-checking routine.

This needed some extensions correct_passwd() function,
which got renamed ask_and_check_password() to better describe what it does.

function                                             old     new   delta
ask_and_check_password_extended                        -     215    +215
ask_and_check_password                                 -      12     +12
vlock_main                                           394     397      +3
sulogin_main                                         494     326    -168
correct_password                                     207       -    -207
------------------------------------------------------------------------------
(add/remove: 2/1 grow/shrink: 1/1 up/down: 230/-375)         Total: -145 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

archival/*: move "config:" snippets into .c files

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

archival/*: move "applet:" snippets into .c files, part 2

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

archival/*: move "applet:" snippets into .c files

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

archival/*: move "kbuild:" snippets into .c files

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

switch editors/* to embedded-in-source kbuild system

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

awk: optionally support -e AWK_PROG

function                                             old     new   delta
awk_main                                             959     978     +19

Signed-off-by: Sven-Göran Bergh <sgb@systemasis.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

fstrim: use new-style config/kbuild/applet snippets; trim help text

function                                             old     new   delta
packed_usage                                       29546   29520     -26

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

udhcp: add PXELINUX config file option (code 209) definition

This change adds a definition for DHCP option 209. RFC 5071 defines code
209 as a configuration file for a PXE bootloader; this change uses
the string "pxeconffile" as its text identifier.

Signed-off-by: Jeremy Kerr <jk@ozlabs.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

fix "warning: ISO C90 forbids mixed declarations and code"

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

fix bashisms in testsuite/

These places use ${var/search/replace}, $((n++) and
`type -p' constructs which are not-so-standard.
Replace with equivalent constructs.

Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

fstrim: Needs to fire at the mp, not bd

It's a filesystem thing from this perspective.
+1b

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

fstrim: Indicate failure on error

+14b

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

fstrim: -17b

Also, use the name of the block device we found, not necessarily the one
we got from the user:
fstrim -v /
/dev/sdj: 4711 bytes were trimmed

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

fstrim: New applet

fstrim applet is a port from util-linux.

"Trimming" your NAND/eMMC storage will restore the write performance
back to normal after having slow down issues on sequential write and
random write due to usage over time.

Good reading on subject:
http://forum.xda-developers.com/showthread.php?t=1971852

(with long options and CLEAN_UP turned on)
function                                             old     new   delta
.rodata                                           148494  148791    +297
fstrim_main                                            -     283    +283
fstrim_sfx                                             -     128    +128
packed_usage                                       28826   28903     +77
applet_main                                         2760    2768      +8
applet_names                                        2343    2350      +7
applet_nameofs                                       690     692      +2
------------------------------------------------------------------------------
(add/remove: 3/0 grow/shrink: 5/0 up/down: 802/0)             Total: 802 bytes

Signed-off-by: Malek Degachi <malek-degachi@laposte.net>
Cc: Eugene San (eugenesan) <eugenesan@gmail.com>
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

ash: Set SHLVL in ASH_BASH_COMPAT

function                                             old     new   delta
ash_main                                            1456    1505     +49
.rodata                                           148488  148494      +6
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 55/0)               Total: 55 bytes

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

ash: Use setvar2 some more

(add/remove: 0/0 grow/shrink: 10/15 up/down: 13/-27)          Total: -14 bytes

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

swaponoff: shrink

function                                             old     new   delta
.rodata                                           148469  148468      -1
swap_on_off_main                                     381     379      -2
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-3)               Total: -3 bytes
   text    data     bss     dec     hex filename
 803030    4090    9504  816624   c75f0 busybox_old
 803027    4090    9504  816621   c75ed busybox_unstripped

udhcpc: allow zero server-id. Closes 6614.

function                                             old     new   delta
bcast_or_ucast                                         -      47     +47
udhcp_send_kernel_packet                             271     295     +24
udhcpc_main                                         2696    2705      +9
udhcp_send_raw_packet                                456     459      +3
send_release                                          90      76     -14
send_renew                                           105      77     -28
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 3/2 up/down: 83/-42)             Total: 41 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

init: fix illegal memory access when max message length is reached

Signed-off-by: Yuan-Hsiang Lee <yhlee@ubnt.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

bootchartd: warn if .config looks wrong

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

Makefile.custom: make "make release" delete .gitignore files too

Signed-off-by: Antony Pavlov <antonynpavlov@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

sed: fix "sed clusternewline" testcase

function                                             old     new   delta
process_files                                       2197    2226     +29
flush_append                                          47      54      +7
get_next_line                                        184     189      +5
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/0 up/down: 41/0)               Total: 41 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

sed: document -E in help text

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

sed: fix memory leak in 'r FILE' command

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

sed: accept -E as a synonym for -r

Signed-off-by: David A. Wheeler <dwheeler@dwheeler.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

udhcpc: make DHCP packets to have at least 300 DHCP bytes

Commit b8b72f02 removed all padding from DHCP packets
to fix operation with buggy servers which can't handle
maximum sized packets.  But it introduced a regression
with buggy routers which drop DHCP packets smaller
than 300 bytes (i.e. 342 byte ethernet packets).
Add back some padding to work around.

function                                             old     new   delta
udhcp_send_kernel_packet                             268     292     +24
udhcp_send_raw_packet                                462     473     +11
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 35/0)               Total: 35 bytes

Signed-off-by: Johannes Stezenbach <js@sig21.net>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

libbb: use <poll.h> instead of <sys/poll.h>

Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

bloat-o-meter: add usage info

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

tail compat: fix header printing for tail -f

Makes tail -f for multiple files display the header only if another (ie. not
currently displayed) file changed.

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

wget: if FEATURE_CLEAN_UP, free(ptr_to_globals)

Signed-off-by: Guilherme Maciel Ferreira <guilherme.maciel.ferreira@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

Fix some compiler warnings emitted by gcc-4.8.0

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

ether-wake: shorten help text, reduce packet buffer size

function                                             old     new   delta
ether_wake_main                                      726     727      +1
packed_usage                                       29468   29434     -34

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

wget: add support for connect timeout

function                                             old     new   delta
open_socket                                           33      64     +31
wget_main                                           2182    2194     +12

Signed-off-by: Lauri Kasanen <curaga@operamail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

init: better --help text

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

awk: fix length(array)

function                                             old     new   delta
evaluate                                            3526    3548     +22

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

wall,crontab: use xopen_as_uid_gid()

This fixes a narrow security race in crontab.

function                                             old     new   delta
xopen_as_uid_gid                                       -      80     +80
seteuid                                                -      64     +64
setegid                                                -      64     +64
setreuid                                               -      37     +37
xseteuid                                               -      22     +22
xsetegid                                               -      22     +22
crontab_main                                         590     577     -13
setfsuid                                              33       -     -33
setfsgid                                              33       -     -33
wall_main                                            138     102     -36
open_as_user                                         109       -    -109

   text    data     bss     dec     hex filename
 893539     497    7568  901604   dc1e4 busybox_old
 893618     497    7568  901683   dc233 busybox_unstripped

Signed-off-by: Ryan Mallon <rmallon@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

libbb: Add xsetegid(), xseteuid(), xopen_as_uid_gid() functions

Signed-off-by: Ryan Mallon <rmallon@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

bunzip2: fix off-by-one check

stage3-armv7a_hardfp-20130209.tar.bz2, 149189948 bytes long,
md5sum b29ce23312e14eb15a143377d4a38473, was failing to unpack.

It so happened that this file has a run which exactly fills
the 90k buffer. The check was "size >= bufsize", apparently
it has to be ">".

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

wall: access FILE under real user's credentials

While at it, move applet/config/kbuild bits into wall.c.
(This way, it's more visible that applet is suid'ed).

function                                             old     new   delta
wall_main                                             87     138     +51

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

trylink: only prefix libs with -l

If our pkg-config queries pass back a flag like -pthread, the trylink
script will expand that to -l-pthread.  So change trylink to only add
the -l prefix to a value that doesn't have a - prefix already.

Reported-by: thaehaid@incognitomail.org
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

loadkmap: explain what happens with K_ALLOCATED key value

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

httpd: make sire pfd[TO_CGI].revents is cleared before poll()

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

Documentation update

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

dumpkmap: code shrink

function                                             old     new   delta
dumpkmap_main                                        223     160     -63

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

httpd: treat errors from stdin correctly.

Fron bug report:

If a CGI or proxied connection is rudely aborted (SIG_{KILL,BUS,SEGV})
then httpd will spin madly the poll loop in:

networking/httpd.c:1080
cgi_io_loop_and_exit()

Upon investigation I found that pfd[0].revents == 0x0018 (POLLHUP|POLLERR),
which leads to empty read, but the pfd[0].fd (STDIN_FILENO) is left open,
and in the FD list given to poll() which immediately returns to once
again inform the loop of (POLLHUP|POLLERR) condition of pfd[0].fd.
This continues until pfd[FROM_CGI].revents != 0

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

touch: add conditional support for -h

Based on a patch by Andy <andy.padavan@gmail.com>

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

ar: better comment

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

ar: read_num(): fix reading fields using the entire width

ar fields are fixed length text strings (padded with spaces). Ensure
bb_strtou doesn't read past the field in case the full width is used.

The fields are only read once, so the simplest/smallest solution to me
seems to be to just pass the length to read_num() and then zero terminate
the string before passing it to bb_strtou. This does mean that the fields
MUST be read in reverse order, so some minor reshuffling was needed.

Bloat-o-meter:
function                                             old     new   delta
get_header_ar                                        394     414     +20
read_num                                              29      36      +7
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 27/0)               Total: 27 bytes

Signed-off-by: Peter Korsgaard <jacmet@sunsite.dk>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

top: fix breakage introduced by previous commit

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

Make smart_ulltoa return pointer to end (allows for code shink in callers)

function                                             old     new   delta
smart_ulltoa5                                        405     408      +3
smart_ulltoa4                                        273     276      +3
list_table                                          1113    1114      +1
scale                                                 36      34      -2
put_lu                                                55      53      -2
ulltoa6_and_space                                     19      14      -5
powertop_main                                       1470    1461      -9

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

man: find posix man pages

Add the 0p/1p/3p sections to the search.

Signed-off-by: John Spencer <maillist-busybox@barfooze.de>
Signed-off-by: Mike Frysinger <vapier@gentoo.org>

fdisk: fix GPT size math errors

Signed-off-by: Jody Bruchon <jody@jodybruchon.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

lineedit: use unicode_strwidth instead of unicode_strlen

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

dd: code shrink

function                                             old     new   delta
dd_main                                             1475    1469      -6

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

dd: code shrink

function                                             old     new   delta
dd_main                                             1487    1475     -12

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

dd: code shrink

function                                             old     new   delta
write_and_stats                                       78      99     +21
dd_main                                             1496    1487      -9
full_write_or_warn                                    42       -     -42
------------------------------------------------------------------------------
(add/remove: 0/1 grow/shrink: 1/1 up/down: 21/-51)            Total: -30 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

dd: remove FIXME comment which is fixed now. No code changes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

dd: code shrink

function                                             old     new   delta
dd_main                                             1001     961     -40

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

dd: fail if swab is attempted on odd-sized block

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

lineedit: fix multi-line PS1 handling: calculate PS1 length from last \n

function                                             old     new   delta
parse_and_put_prompt                                 755     774     +19

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

lineedit: improve Unicode handling (still buggy though)

function                                             old     new   delta
unicode_strlen                                         -      31     +31
read_line_input                                     3876    3879      +3
lineedit_read_key                                    255     246      -9
parse_and_put_prompt                                 785     755     -30
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/2 up/down: 34/-39)             Total: -5 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

dd: fix example in a comment. No code changes.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

dd: support conv=swab

function                                             old     new   delta
dd_main                                             1482    1520     +38
static.conv_words                                     28      33      +5
packed_usage                                       29377   29375      -2

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

dd: do not reuse local variables for unrelated values.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

iplink: comment out include <net/if_packet.h>

iplink.c includes net/if_packet.h, which (on GLIBC)
only defines struct sockaddr_pkt. this struct is not
used anywhere in the code, and removing the #include
makes compilation succeed with musl libc.

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

init: don't srop unterminated processes' entries during inittab reload

This feature was removed in 72c99af

It is useful when process is removed from inittab and later added
back, but never terminated. It prevents init from spawning duplicate.

function                                             old     new   delta
check_delayed_sigs                                   176     182      +6

Signed-off-by: Paulius Zaleckas <paulius.zaleckas@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

init: don't use fixed size buffer for command

We store init actions forever. 256 bytes per action means that
a typical inittab of ~10 commands uses 2.5k just to remember
command strings - which are usually _much_ shorter than 256 bytes.

At a cost of a bit more code, it's possible to allocate
only actually needed amount.

function                                             old     new   delta
init_exec                                            224     248     +24
new_init_action                                      140     142      +2

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

tar: fix tar -T to add entries in the exact order as the input list

This fixes tar to order files in tarball correctly in this case:

$ touch 1 2 3; echo -e '1\n2\n3' | tar -T- -c | tar t
1
2
3

Signed-off-by: SASAKI Suguru <suguru@sonik.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

fix build error with musl libc due to if_slip.h

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

networking: fix potential overflow in ife_print6()

devname is used by fscanf to store a string specified by '%20s'.

Extract from the man for the '%s' specifier:
Matches a sequence of non-white-space characters; the next pointer must be a
pointer to character array that is long enough to hold the input sequence and
the terminating null byte ('\0'), which is added automatically. The input
string stops at white space or at the maximum field width, whichever occurs
first.

Hence, the right length is 20 + 1 for the '\0'.

Signed-off-by: Nicolas Dichtel <nicolas.dichtel@6wind.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

udhcpc: tweak help text more

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

udhcpc: tweak help text

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

swapon: support "pri=NNN" in fstab

function                                             old     new   delta
swap_on_off_main                                     244     365    +121

Signed-off-by: Tito Ragusa <farmatito@tiscali.it>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

setsid: code shrink, expanded comments

function                                             old     new   delta
setsid_main                                           56      53      -3

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

libbb: code shrink

function                                             old     new   delta
xmalloc_ttyname                                       46      42      -4

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

udhcpc: tweak help text

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

syslogd: use _PATH_LOG when available

Signed-off-by: Cédric Cabessa <ccabessa@genymobile.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

ubi_tools: fix typo in strcpy

Signed-off-by: Paul B. Henson <henson@acm.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

ifplugd: use a larger netlink buffer

function                                             old     new   delta
check_existence_through_netlink                      310     321     +11

Signed-off-by: Tito Ragusa <farmatito@tiscali.it>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

less: support "less 1<>TTY"

function                                             old     new   delta
less_main                                           2466    2507     +41
xmalloc_ttyname                                       46      42      -4

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

volume_id: add f2fs detection

function                                             old     new   delta
volume_id_probe_f2fs                                   -      98     +98

Signed-off-by: Sven-Göran Bergh <sgb@systemasis.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

awk: Fix handling of functions with empty body

ammend b79a0fef99627c457548e804fcd6e162b116cbe8 to properly
handle functions defined in another scope.

Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>

volume_id: nilfs config description.

Config description for nilfs added.

No code change.

Signed-off-by: Sven-Göran Bergh <sgb@systemasis.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

volume_id: Adopt to new config style.

Config instructions for util-linux/volume_id are moved into the
source files according to the new config feature.

No code change.

Signed-off-by: Sven-Göran Bergh <sgb@systemasis.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

volume_id: Adopt to new kbuild style.

Kbuild instructions for util-linux/volume_id are moved into the
source files according to the new build feature.

No code change.

Signed-off-by: Sven-Göran Bergh <sgb@systemasis.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

Whitespace fixes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

catv: code shrink

catv_main                                            250     227     -23

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

Refactor catv. Move visible() from stty to libbb.

Fixes the following TODO:

  stty's visible() function and catv's guts are identical. Merge them into
  an appropriate libbb function.

Also makes catv behave exactly like coreutils' cat -v e.g. it'll print 'M-^I'
instead of 'M-   '.

function                                             old     new   delta
visible                                                -      70     +70
do_display                                           431     379     -52
catv_main                                            306     250     -56
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/2 up/down: 70/-108)           Total: -38 bytes

Signed-off-by: Bartosz Golaszewski <bartekgola@gmail.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

unpackers: by users' request, print compression percentage if -v and DESKTOP

function                                             old     new   delta
bbunpack                                             634     731     +97

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

nc: remove unnecessary "errno = 0"

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>