The memcpy invocations in the subCommand function, modified by this
commit, previously used memcpy with overlapping memory regions. This is
undefined behavior. On Alpine Linux, it causes BusyBox ed to crash since
we compile BusyBox with -D_FORTIFY_SOURCE=2 and our fortify-headers
implementation catches this source of undefined behavior [0]. The issue
can only be triggered if the replacement string is the same size or
shorter than the old string.
Looking at the code, it seems to me that a memmove(3) is what was
actually intended here, this commit modifies the code accordingly.
[0]: https://gitlab.alpinelinux.org/alpine/aports/-/issues/13504
Signed-off-by: Sören Tempel <soeren+git@soeren-tempel.net>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Apart from the -p option, POSIX also mandates an -s option which
suppresses the output of byte counts for the e, E, r, and w command.
From these commands, Busybox ed presently only implements the r and w
commands. This commit ensures that these two command do not output any
bytes counts when the -s option is passed. The shell escape command,
also effected by the -s option, is not implemented by Busybox at the
moment.
function old new delta
packed_usage 34096 34115 +19
doCommands 1887 1900 +13
readLines 388 397 +9
.rodata 104196 104200 +4
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 4/0 up/down: 45/0) Total: 45 bytes
Signed-off-by: Sören Tempel <soeren+git@soeren-tempel.net>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
POSIX.1-2008 mandates the following regarding the read command:
If the read is successful, and -s was not specified, the number
of bytes read shall be written to standard output in the
following format:
"%d\n", <number of bytes read>
This commit aligns the output of busybox ed with POSIX.1-2008 by
removing the file name from the output for the read command.
This slipped through in 4836a0708fd0aaeb82871a3762b40fcf4b61e812.
function old new delta
.rodata 104203 104196 -7
readLines 409 388 -21
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-28) Total: -28 bytes
Signed-off-by: Sören Tempel <soeren+git@soeren-tempel.net>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
POSIX.1-2008 mandates the following regarding the file command-line
argument:
If the file argument is given, ed shall simulate an e command
on the file named by the pathname […]
The specification for the e command mandates the following behaviour
regarding the current line number in POSIX.1-2008:
The current line number shall be set to the address of the last
line of the buffer.
However, without this commit, busybox ed will set the current line
number to 1 if a file is given on the command-line and this file is not
empty (lastNum != 0). This is incorrect and fixed in this commit by not
modifying the current line number in ed_main(). As such, the current
line number will be zero for empty files and otherwise be set to the
address of the last line of the buffer.
function old new delta
ed_main 144 128 -16
Signed-off-by: Sören Tempel <soeren+git@soeren-tempel.net>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
The POSIX.1-2008 specification of ed(1) mandates two command-line
options: -p (for specifying a prompt string) and -s (to suppress writing
of byte counts). This commit adds support for the former. Furthermore,
it also changes the default prompt string to an empty string (instead
of ": ") since this is also mandated by POSIX:
-p string Use string as the prompt string when in command mode.
By default, there shall be no prompt string.
function old new delta
ed_main 112 144 +32
packed_usage 34074 34097 +23
doCommands 1889 1887 -2
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/1 up/down: 55/-2) Total: 53 bytes
Signed-off-by: Sören Tempel <soeren+git@soeren-tempel.net>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
POSIX.1-2008 mandates the following regarding the write command:
If the command is successful, the number of bytes written shall
be written to standard output, unless the -s option was
specified, in the following format:
"%d\n", <number of bytes written>
function old new delta
readLines 447 409 -38
doCommands 1940 1889 -51
.rodata 104219 104163 -56
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-145) Total: -145 bytes
Signed-off-by: Sören Tempel <soeren+git@soeren-tempel.net>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Back in 2007, commit 0c97c9d437 ("'simple' error message functions by
Loic Grenie") introduced bb_simple_perror_msg() to allow for a lower
overhead call to bb_perror_msg() when only a string was being printed
with no parameters. This saves space for some CPU architectures because
it avoids the overhead of a call to a variadic function. However there
has never been a simple version of bb_error_msg(), and since 2007 many
new calls to bb_perror_msg() have been added that only take a single
parameter and so could have been using bb_simple_perror_message().
This changeset introduces 'simple' versions of bb_info_msg(),
bb_error_msg(), bb_error_msg_and_die(), bb_herror_msg() and
bb_herror_msg_and_die(), and replaces all calls that only take a
single parameter, or use something like ("%s", arg), with calls to the
corresponding 'simple' version.
Since it is likely that single parameter calls to the variadic functions
may be accidentally reintroduced in the future a new debugging config
option WARN_SIMPLE_MSG has been introduced. This uses some macro magic
which will cause any such calls to generate a warning, but this is
turned off by default to avoid use of the unpleasant macros in normal
circumstances.
This is a large changeset due to the number of calls that have been
replaced. The only files that contain changes other than simple
substitution of function calls are libbb.h, libbb/herror_msg.c,
libbb/verror_msg.c and libbb/xfuncs_printf.c. In miscutils/devfsd.c,
networking/udhcp/common.h and util-linux/mdev.c additonal macros have
been added for logging so that single parameter and multiple parameter
logging variants exist.
The amount of space saved varies considerably by architecture, and was
found to be as follows (for 'defconfig' using GCC 7.4):
Arm: -92 bytes
MIPS: -52 bytes
PPC: -1836 bytes
x86_64: -938 bytes
Note that for the MIPS architecture only an exception had to be made
disabling the 'simple' calls for 'udhcp' (in networking/udhcp/common.h)
because it made these files larger on MIPS.
Signed-off-by: James Byrne <james.byrne@origamienergy.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
