Run this in a "sh SCRIPT":
sha256sum /dev/null
echo END
sha256sum is a NOEXEC applet. It runs in a forked child. Then child exit()s.
By this time, entire script is read, and buffered in a FILE object
from fopen("SCRIPT"). But fgetc() did not consume entire input.
exit() lseeks back by -9 bytes, from <eof> to 'e' in 'echo'.
(this may be libc-specific).
This change of fd position *is shared with the parent*!
Now parent can read more, and it thinks there is another "echo END".
End result: two "echo END"s are run.
Fix this by _exit()ing instead.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
On user request.
I thought enabling/disabling them all together is more consistent.
Evidently, some people do want them to be separately selectable.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
When busybox is configured to contain a single applet an unnecessary
declaration of run_applet_and_exit results in a warning. Move the
declaration to avoid this.
Reported-by: Lauri Kasanen <curaga@operamail.com>
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Both calls to run_applet_and_exit are followed by the same code
to print an error message and return status 127. Remove this
duplication and make run_applet_and_exit static.
function old new delta
run_applet_and_exit 675 667 -8
main 119 92 -27
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-35) Total: -35 bytes
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
A recent commit made it possible to disable BusyBox's --install
and --list options. However it also stopped "busybox <applet>
<params>" from working.
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
If it's disabled, code shrinks by about 900 bytes:
function old new delta
usr_bin 10 - -10
usr_sbin 11 - -11
install_dir 20 - -20
applet_install_loc 184 - -184
run_applet_and_exit 686 21 -665
------------------------------------------------------------------------------
(add/remove: 0/4 grow/shrink: 0/1 up/down: 0/-890) Total: -890 bytes
text data bss dec hex filename
911327 493 7336 919156 e0674 busybox_old
909848 493 7336 917677 e00ad busybox_unstripped
but busybox executable by itself does not say anything useful:
$ busybox
busybox: applet not found
Based on the patch by Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
The result of looking at "grep -F -B2 '*fill*' busybox_unstripped.map"
text data bss dec hex filename
829901 4086 1904 835891 cc133 busybox_before
829665 4086 1904 835655 cc047 busybox
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
The loop
for (j = ARRAY_SIZE(applet_nameofs)-1; j >= 0; j--) {
was intended to terminate when j goes negative, so j needs to be signed.
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
The array applet_nameofs consumes two bytes per applet. It encodes
nofork/noexec flags
suid flags
the offset of the applet name in the applet_name string
Change the applet_table build tool to store the flags in two separate
arrays (applet_flags and applet_suid). Replace applet_nameofs[] with a
smaller version that only stores a limited number of offsets.
This requires changes to the macros APPLET_IS_NOFORK, APPLET_IS_NOEXEC
and APPLET_SUID.
According to Valgrind the original find_applet_by_name required
353 cycles per call, averaged over all names. Adjusting the number
of known offsets allows space to be traded off against execution time:
KNOWN_OFFSETS cycles bytes (wrt KNOWN_OFFSETS = 0)
0 9057 -
2 4604 32
4 2407 75
8 1342 98
16 908 130
32 884 194
This patch uses KNOWN_OFFSETS = 8.
v2:
Remove some dead code from the applet_table tool;
Treat the applet in the middle of the table as a special case.
v3:
Use the middle applet to adjust the start of the linear search as
well as the last applet found.
v4:
Use an augmented linear search in find_applet_by_name.
Drop the special treatment of the middle name from get_applet_name:
most of the advantage now derives from the last stored value.
v5:
Don't store index in applet_nameofs, it can be calculated.
v6:
Tweaks by Denys
function old new delta
find_applet_by_name 25 125 +100
applet_suid - 92 +92
run_applet_no_and_exit 452 460 +8
run_applet_and_exit 695 697 +2
applet_name_compare 31 - -31
applet_nameofs 734 14 -720
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 3/1 up/down: 202/-751) Total: -549 bytes
text data bss dec hex filename
925464 906 17160 943530 e65aa busybox_old
924915 906 17160 942981 e6385 busybox_unstripped
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
In standalone shell mode search the applet table as well as PATH
when tab completing a command.
Use a stupid linear search: we're also about to read all the
directories on PATH so efficiency isn't a big concern.
function old new delta
add_match - 53 +53
complete_cmd_dir_file 687 724 +37
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 1/0 up/down: 90/0) Total: 90 bytes
Signed-off-by: Ron Yorston <rmy@frippery.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
MONOTONIC_SYSCALL=y by default
FEATURE_LAST_SMALL is gone: now FEATURE_LAST_FANCY is a "bool", not a "choice".
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
systemd people are not willing to play nice with the rest of the world.
Therefore there is no reason for the rest of the world to cooperate with them.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
invarg(a,b) - "invalid argument", but how a and b enter the message?
invarg_1_to_2(a,b) is somewhat easier to read: "invalid argument 'a' to 'b'"
Audit of usage revealed a number of bad uses, with too long messages.
text data bss dec hex filename
938848 932 17448 957228 e9b2c busybox_old
938788 932 17448 957168 e9af0 busybox_unstripped
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
