path: root/libbb/read_printf.c
diff options
authorGravatar James Byrne <james.byrne@origamienergy.com>2019-07-02 11:35:03 +0200
committerGravatar Denys Vlasenko <vda.linux@googlemail.com>2019-07-02 11:35:03 +0200
commit6937487be73cd4563b876413277a295a5fe2f32c (patch)
treef16cc9999a7c827891e6ec8d99c699fc791008ee /libbb/read_printf.c
parentcaecfdc20d450686cd1f7e9b5f650322f894b3c2 (diff)
libbb: reduce the overhead of single parameter bb_error_msg() calls
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 <james.byrne@origamienergy.com> Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'libbb/read_printf.c')
1 files changed, 1 insertions, 1 deletions
diff --git a/libbb/read_printf.c b/libbb/read_printf.c
index cb582c080..0cd04ab7b 100644
--- a/libbb/read_printf.c
+++ b/libbb/read_printf.c
@@ -217,7 +217,7 @@ void FAST_FUNC xread(int fd, void *buf, size_t count)
if (count) {
ssize_t size = full_read(fd, buf, count);
if ((size_t)size != count)
- bb_error_msg_and_die("short read");
+ bb_simple_error_msg_and_die("short read");