head,tail: use common suffix struct. simplify help text.

function                                             old     new   delta
head_tail_suffixes                                     -      32     +32
head_main                                            415     406      -9
packed_usage                                       29252   29234     -18
tail_suffixes                                         32       -     -32
head_suffixes                                         32       -     -32
------------------------------------------------------------------------------
(add/remove: 2/2 grow/shrink: 0/2 up/down: 32/-91)            Total: -59 bytes
   text    data     bss     dec     hex filename
 890474     497    7584  898555   db5fb busybox_old
 890415     497    7584  898496   db5c0 busybox_unstripped

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
head: support -n -NUM and -c -NUM

function                                             old     new   delta
head_main                                            406     832    +426
packed_usage                                       29234   29252     +18
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 444/0)             Total: 444 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
tail: make help text for -n +N syntax more correct

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
move endofname() to libbb

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
mdev: add environment variable match

function                                             old     new   delta
make_device                                         1998    2189    +191
clean_up_cur_rule                                     61      96     +35
dirAction                                             75      87     +12
mdev_main                                            838     849     +11
packed_usage                                       29272   29273      +1
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 5/0 up/down: 250/0)             Total: 250 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
udhcpc: support resolv.conf symlinks

Often it is desirable to have /etc/ be on read-only storage (well, the
whole rootfs) but have things like /etc/resolv.conf be symlinks to a
writable location.  Tweak the simple script to support that.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
udhcpc: tweak math shell style with the metric var

Some shells (like dash) are lame and omit the POSIX increment/decrement
feature (because it is listed as optional).  Tweak the shell script to
work in all POSIX variants.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
mdev: improve $SEQ handling; improve debug logging

Sequential run of concurrent mdev's was too simplistic:
they waited for /dev/mdev.seq to match. This could sometimes
cause cumulative loss of time on the order of a second.

Added SIGCHLD signaling from exiting mdev to all other mdev's.
Added debugging required to see that code actually works as intended.

Example of /dev/mdev.log (with "woken up" elevated from dbg lvl 3 to 2):

mdev[1023]: first seq written
     ^^^^ seq, not pid
mdev[1023]: 35.022395 ACTION:add SUBSYSTEM:module DEVNAME:(null) DEVPATH:/module/lib80211
mdev[1023]: rule matched, line -1
                          ^^^^^^^ means "default rule"
mdev[1023]: 35.022676 exiting
            ^^^^^^^^^ second,usec timestamp
mdev[1024]: 35.069691 ACTION:add SUBSYSTEM:vc DEVNAME:vcs9 DEVPATH:/devices/virtual/vc/vcs9
mdev[1024]: dev 7,9
mdev[1025]: 35.069889 waiting for '1024'
mdev[1026]: 35.069946 waiting for '1024'
mdev[1027]: 35.070151 waiting for '1024'
mdev[1024]: rule matched, line -1
mdev[1024]: mknod vcs9 (7,9) 20660 0:0
mdev[1024]: 35.070346 exiting
mdev[1025]: woken up
mdev[1026]: woken up
mdev[1025]: 35.071213 ACTION:add SUBSYSTEM:vc DEVNAME:vcsa9 DEVPATH:/devices/virtual/vc/vcsa9
            ^^^^^^^^^ took only a millisecond to start running after prev mdev exited
mdev[1025]: dev 7,137
mdev[1027]: woken up
mdev[1025]: rule matched, line -1
mdev[1025]: mknod vcsa9 (7,137) 20660 0:0
mdev[1025]: 35.072109 exiting

function                                             old     new   delta
mdev_main                                            849    1372    +523
curtime                                                -      59     +59
dirAction                                             87     134     +47
static.ts                                              -       8      +8
keywords                                              19      12      -7
make_device                                         2189    2119     -70

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Fix move_to_unaligned16

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
xz: omit explicit \0 from HEADER_MAGIC

Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
xz: update README

Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
xz: avoid "NOTE:" in xz.h

Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
xz: add a comment about using uint32_t as vli_type

Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
xz: make bcj_x86_test_msbyte() an inline function

Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
xz: remove an empty line from xz_dec_lzma2.c

Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
cz: add C++ support to xz.h

Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
xz: fix decoding of LZMA2 streams having no uncompressed data.

No .xz encoder creates files with empty LZMA2 streams,
but such files would still be valid and decompressors
must accept them.

Note that empty .xz files are a different thing than
empty LZMA2 streams. This bug didn't affect typical .xz
files that had no uncompressed data.

Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
xz: fix incorrect XZ_BUF_ERROR

xz_dec_run() could incorrectly return XZ_BUF_ERROR if
all of the following was true:

  - The caller knows how many bytes of output to expect
    and only provides that much output space.

  - When the last output bytes are decoded, the
    caller-provided input buffer ends right before
    the LZMA2 end of payload marker. So LZMA2 won't
    provide more output anymore, but it won't know it
    yet and thus won't return XZ_STREAM_END yet.

  - A BCJ filter is in use and it hasn't left any
    unfiltered bytes in the temp buffer. This can happen
    with any BCJ filter, but in practice it's more likely
    with filters other than the x86 BCJ.

This fixes <https://bugzilla.redhat.com/show_bug.cgi?id=735408>
where Squashfs thinks that a valid file system is corrupt.
Thanks to Jindrich Novy for telling me that such a bug report
exists, Phillip Lougher for providing excellent debug info,
and other people on #fedora-ppc.

This also fixes a similar bug in single-call mode where the
uncompressed size of a XZ Block using BCJ + LZMA2 was 0 bytes
and caller provided no output space. Many empty .xz files
don't contain any Blocks and thus don't trigger this bug.

This also tweaks a closely related detail: xz_dec_bcj_run()
could call xz_dec_lzma2_run() to decode into temp buffer when
it was known to be useless. This was harmless although it
wasted a minuscule number of CPU cycles.

Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
xz: mention xzminidec.c in README

Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
xz: support concatenated .xz streams

function                                             old     new   delta
xz_dec_reset                                           -      77     +77
unpack_xz_stream                                    2402    2397      -5

Signed-off-by: Lasse Collin <lasse.collin@tukaani.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>