libbb: reverse performance regression in bb_copyfd_*

2026-05-10T12:00:34+00:00

Commit c4f24ec9d (libbb: try to mitigate 'cat /dev/urandom') resulted in a 'cat' to the terminal taking ~25% longer than before. Raising the isatty() call out of the loop reduces the penalty to ~1%. Adds 16 bytes in the 32-bit build. (GitHub issue #585)

libbb: try to mitigate 'cat /dev/urandom'

2026-05-08T13:18:44+00:00

Now that '/dev/urandom' can be used directly, people with a sense of curiosity and adventure have tried running 'cat /dev/urandom' or 'cat

libbb: create and use mmap() helpers

2020-12-14T17:25:28+00:00

function old new delta mmap_anon - 22 +22 mmap_read - 21 +21 xmmap_anon - 16 +16 rpm_gettags 465 447 -18 bb_full_fd_action 498 480 -18 uevent_main 337 310 -27 ------------------------------------------------------------------------------ (add/remove: 3/0 grow/shrink: 0/3 up/down: 59/-63) Total: -4 bytes Signed-off-by: Denys Vlasenko

dpkg-deb: work around bogus error message when working with XZ compressed packages

2019-10-11T12:11:44+00:00

function old new delta unpack_xz_stream 2309 2317 +8 bb_full_fd_action 464 472 +8 Signed-off-by: Denys Vlasenko

libbb: reduce the overhead of single parameter bb_error_msg() calls

2019-07-02T09:35:03+00:00

Back in 2007, commit 0c97c9d43707 ("'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 Signed-off-by: Denys Vlasenko

whitespace and comment format fixes, no code changes

2017-10-05T12:40:24+00:00

Signed-off-by: Denys Vlasenko

copyfd: guard use of munmap() with #if (windows builds need this)

2017-07-15T09:44:13+00:00

Signed-off-by: Johannes Schindelin Signed-off-by: Denys Vlasenko

libbb: use sendfile() to copy data between file descriptors

2014-11-27T22:31:58+00:00

Busybox already uses sendfile in httpd. This patch proposes to use it globally to copy data between file descriptors. It speeds up the copying on slow systems a lot - below are the times needed to copy a 450Mb file with and without this option enabled on a BeagleBone Black: sendfile: user 0m0.000s sys 0m8.170s read/write 4k: user 0m0.470s sys 0m16.300s function old new delta bb_full_fd_action 394 474 +80 Signed-off-by: Bartosz Golaszewski Signed-off-by: Denys Vlasenko

*: make GNU licensing statement forms more regular

2010-08-16T18:14:46+00:00

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

libbb/copyfd.c: fix the case of copy buffer <= 4kb

2010-06-26T21:08:59+00:00