6937487be7
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>
81 lines
2.3 KiB
C
81 lines
2.3 KiB
C
/* vi: set sw=4 ts=4: */
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/*
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* mesg implementation for busybox
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*
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* Copyright (c) 2002 Manuel Novoa III <mjn3@codepoet.org>
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*
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* Licensed under GPLv2 or later, see file LICENSE in this source tree.
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*/
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//config:config MESG
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//config: bool "mesg (1.4 kb)"
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//config: default y
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//config: help
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//config: Mesg controls access to your terminal by others. It is typically
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//config: used to allow or disallow other users to write to your terminal
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//config:
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//config:config FEATURE_MESG_ENABLE_ONLY_GROUP
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//config: bool "Enable writing to tty only by group, not by everybody"
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//config: default y
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//config: depends on MESG
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//config: help
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//config: Usually, ttys are owned by group "tty", and "write" tool is
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//config: setgid to this group. This way, "mesg y" only needs to enable
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//config: "write by owning group" bit in tty mode.
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//config:
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//config: If you set this option to N, "mesg y" will enable writing
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//config: by anybody at all. This is not recommended.
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//applet:IF_MESG(APPLET_NOFORK(mesg, mesg, BB_DIR_USR_BIN, BB_SUID_DROP, mesg))
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//kbuild:lib-$(CONFIG_MESG) += mesg.o
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//usage:#define mesg_trivial_usage
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//usage: "[y|n]"
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//usage:#define mesg_full_usage "\n\n"
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//usage: "Control write access to your terminal\n"
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//usage: " y Allow write access to your terminal\n"
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//usage: " n Disallow write access to your terminal"
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#include "libbb.h"
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#if ENABLE_FEATURE_MESG_ENABLE_ONLY_GROUP
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#define S_IWGRP_OR_S_IWOTH S_IWGRP
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#else
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#define S_IWGRP_OR_S_IWOTH (S_IWGRP | S_IWOTH)
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#endif
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int mesg_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
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int mesg_main(int argc UNUSED_PARAM, char **argv)
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{
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struct stat sb;
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mode_t m;
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char c = 0;
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argv++;
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if (argv[0]
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&& (argv[1] || ((c = argv[0][0]) != 'y' && c != 'n'))
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) {
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bb_show_usage();
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}
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/* We are a NOFORK applet.
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* (Not that it's very useful, but code is trivially NOFORK-safe).
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* Play nice. Do not leak anything.
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*/
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if (!isatty(STDIN_FILENO))
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bb_simple_error_msg_and_die("not a tty");
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xfstat(STDIN_FILENO, &sb, "stdin");
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if (c == 0) {
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puts((sb.st_mode & (S_IWGRP|S_IWOTH)) ? "is y" : "is n");
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return EXIT_SUCCESS;
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}
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m = (c == 'y') ? sb.st_mode | S_IWGRP_OR_S_IWOTH
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: sb.st_mode & ~(S_IWGRP|S_IWOTH);
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if (fchmod(STDIN_FILENO, m) != 0)
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bb_perror_nomsg_and_die();
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return EXIT_SUCCESS;
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}
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