The '%' character in a format specification may be followed by
one or more flags from the list "+- #0". BusyBox printf didn't
support the '0' flag or allow multiple flags to be provided.
As a result the formats '%0*d' and '%0 d' were considered to be
invalid.
The lack of support for '0' was pointed out by Andrew Snyder on the
musl mailing list:
https://www.openwall.com/lists/musl/2021/12/14/2
function old new delta
printf_main 860 891 +31
.rodata 99281 99282 +1
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(add/remove: 0/0 grow/shrink: 2/0 up/down: 32/0) Total: 32 bytes
Signed-off-by: Ron Yorston <rmy@pobox.com>
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>
Thanks to Cristian Ionescu-Idbohrn for noticing.
Also fix "%d" ' 42' to skip leading whitespace.
function old new delta
print_direc 435 454 +19
bb_strtoll 99 103 +4
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(add/remove: 0/0 grow/shrink: 2/0 up/down: 23/0) Total: 23 bytes
Signed-off-by: Bernhard Reutner-Fischer <rep.dot.nop@gmail.com>
One of the tests for printf checks for an invalid bare '%' in the
format string:
$ busybox printf '%' a b c
printf: %: invalid format
On x86_64 a slightly different test doesn't work correctly:
$ busybox printf '%' d e f
printf: invalid number 'd'
printf: invalid number 'e'
printf: invalid number 'f'
On other platforms the test fails randomly depending on how the
arguments are laid out in memory.
There are two places in the code where strchr is used to determine if
a character in the format string is valid. However, strchr also returns
a valid pointer if the character being searched for is the null terminator
thus causing the code to incorrectly suppose that a valid character has
been found.
Add explicit checks for the null terminator.
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
printf wasn't correctly handling \c in an argument to the %b format
specifier.
printf %bXX OK\\c
returned 'OK\cXX' rather than the expected 'OK'.
function old new delta
printf_main 886 899 +13
Signed-off-by: Ron Yorston <rmy@pobox.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
It was not accepting \0NNN. Standard printf tool does.
function old new delta
printf_main 869 886 +17
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This change retains "or later" state! No licensing _changes_ here,
only form is adjusted (article, space between "GPL" and "v2" and so on).
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
