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busybox/runit/chpst.c
James Byrne 6937487be7 libbb: reduce the overhead of single parameter bb_error_msg() calls 
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>
2019-07-02 11:35:03 +02:00

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/*
Copyright (c) 2001-2006, Gerrit Pape
All rights reserved.
Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:
1. Redistributions of source code must retain the above copyright notice,
this list of conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright
notice, this list of conditions and the following disclaimer in the
documentation and/or other materials provided with the distribution.
3. The name of the author may not be used to endorse or promote products
derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE AUTHOR ''AS IS'' AND ANY EXPRESS OR IMPLIED
WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO
EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/* Busyboxed by Denys Vlasenko <vda.linux@googlemail.com> */
//config:config CHPST
//config: bool "chpst (9 kb)"
//config: default y
//config: help
//config: chpst changes the process state according to the given options, and
//config: execs specified program.
//config:
//config:config SETUIDGID
//config: bool "setuidgid (4 kb)"
//config: default y
//config: help
//config: Sets soft resource limits as specified by options
//config:
//config:config ENVUIDGID
//config: bool "envuidgid (3.9 kb)"
//config: default y
//config: help
//config: Sets $UID to account's uid and $GID to account's gid
//config:
//config:config ENVDIR
//config: bool "envdir (2.5 kb)"
//config: default y
//config: help
//config: Sets various environment variables as specified by files
//config: in the given directory
//config:
//config:config SOFTLIMIT
//config: bool "softlimit (4.5 kb)"
//config: default y
//config: help
//config: Sets soft resource limits as specified by options
//applet:IF_CHPST( APPLET_NOEXEC(chpst, chpst, BB_DIR_USR_BIN, BB_SUID_DROP, chpst))
// APPLET_NOEXEC:name main location suid_type help
//applet:IF_ENVDIR( APPLET_NOEXEC(envdir, chpst, BB_DIR_USR_BIN, BB_SUID_DROP, envdir))
//applet:IF_ENVUIDGID(APPLET_NOEXEC(envuidgid, chpst, BB_DIR_USR_BIN, BB_SUID_DROP, envuidgid))
//applet:IF_SETUIDGID(APPLET_NOEXEC(setuidgid, chpst, BB_DIR_USR_BIN, BB_SUID_DROP, setuidgid))
//applet:IF_SOFTLIMIT(APPLET_NOEXEC(softlimit, chpst, BB_DIR_USR_BIN, BB_SUID_DROP, softlimit))
//kbuild:lib-$(CONFIG_CHPST) += chpst.o
//kbuild:lib-$(CONFIG_ENVDIR) += chpst.o
//kbuild:lib-$(CONFIG_ENVUIDGID) += chpst.o
//kbuild:lib-$(CONFIG_SETUIDGID) += chpst.o
//kbuild:lib-$(CONFIG_SOFTLIMIT) += chpst.o
//usage:#define chpst_trivial_usage
//usage: "[-vP012] [-u USER[:GRP]] [-U USER[:GRP]] [-e DIR]\n"
//usage: " [-/ DIR] [-n NICE] [-m BYTES] [-d BYTES] [-o N]\n"
//usage: " [-p N] [-f BYTES] [-c BYTES] PROG ARGS"
//usage:#define chpst_full_usage "\n\n"
//usage: "Change the process state, run PROG\n"
//usage: "\n -u USER[:GRP] Set uid and gid"
//usage: "\n -U USER[:GRP] Set $UID and $GID in environment"
//usage: "\n -e DIR Set environment variables as specified by files"
//usage: "\n in DIR: file=1st_line_of_file"
//usage: "\n -/ DIR Chroot to DIR"
//usage: "\n -n NICE Add NICE to nice value"
//usage: "\n -m BYTES Same as -d BYTES -s BYTES -l BYTES"
//usage: "\n -d BYTES Limit data segment"
//usage: "\n -o N Limit number of open files per process"
//usage: "\n -p N Limit number of processes per uid"
//usage: "\n -f BYTES Limit output file sizes"
//usage: "\n -c BYTES Limit core file size"
//usage: "\n -v Verbose"
//usage: "\n -P Create new process group"
//usage: "\n -0 Close stdin"
//usage: "\n -1 Close stdout"
//usage: "\n -2 Close stderr"
//usage:
//usage:#define envdir_trivial_usage
//usage: "DIR PROG ARGS"
//usage:#define envdir_full_usage "\n\n"
//usage: "Set various environment variables as specified by files\n"
//usage: "in the directory DIR, run PROG"
//usage:
//usage:#define envuidgid_trivial_usage
//usage: "USER PROG ARGS"
//usage:#define envuidgid_full_usage "\n\n"
//usage: "Set $UID to USER's uid and $GID to USER's gid, run PROG"
//usage:
//usage:#define setuidgid_trivial_usage
//usage: "USER PROG ARGS"
//usage:#define setuidgid_full_usage "\n\n"
//usage: "Set uid and gid to USER's uid and gid, drop supplementary group ids,\n"
//usage: "run PROG"
//usage:
//usage:#define softlimit_trivial_usage
//usage: "[-a BYTES] [-m BYTES] [-d BYTES] [-s BYTES] [-l BYTES]\n"
//usage: " [-f BYTES] [-c BYTES] [-r BYTES] [-o N] [-p N] [-t N]\n"
//usage: " PROG ARGS"
//usage:#define softlimit_full_usage "\n\n"
//usage: "Set soft resource limits, then run PROG\n"
//usage: "\n -a BYTES Limit total size of all segments"
//usage: "\n -m BYTES Same as -d BYTES -s BYTES -l BYTES -a BYTES"
//usage: "\n -d BYTES Limit data segment"
//usage: "\n -s BYTES Limit stack segment"
//usage: "\n -l BYTES Limit locked memory size"
//usage: "\n -o N Limit number of open files per process"
//usage: "\n -p N Limit number of processes per uid"
//usage: "\nOptions controlling file sizes:"
//usage: "\n -f BYTES Limit output file sizes"
//usage: "\n -c BYTES Limit core file size"
//usage: "\nEfficiency opts:"
//usage: "\n -r BYTES Limit resident set size"
//usage: "\n -t N Limit CPU time, process receives"
//usage: "\n a SIGXCPU after N seconds"
#include "libbb.h"
/*
Five applets here: chpst, envdir, envuidgid, setuidgid, softlimit.
Only softlimit and chpst are taking options:
# common
-o N Limit number of open files per process
-p N Limit number of processes per uid
-m BYTES Same as -d BYTES -s BYTES -l BYTES [-a BYTES]
-d BYTES Limit data segment
-f BYTES Limit output file sizes
-c BYTES Limit core file size
# softlimit
-a BYTES Limit total size of all segments
-s BYTES Limit stack segment
-l BYTES Limit locked memory size
-r BYTES Limit resident set size
-t N Limit CPU time
# chpst
-u USER[:GRP] Set uid and gid
-U USER[:GRP] Set $UID and $GID in environment
-e DIR Set environment variables as specified by files in DIR
-/ DIR Chroot to DIR
-n NICE Add NICE to nice value
-v Verbose
-P Create new process group
-0 -1 -2 Close fd 0,1,2
Even though we accept all these options for both softlimit and chpst,
they are not to be advertised on their help texts.
We have enough problems with feature creep in other people's
software, don't want to add our own.
envdir, envuidgid, setuidgid take no options, but they reuse code which
handles -e, -U and -u.
*/
enum {
OPT_a = (1 << 0) * ENABLE_SOFTLIMIT,
OPT_c = (1 << 1) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
OPT_d = (1 << 2) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
OPT_f = (1 << 3) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
OPT_l = (1 << 4) * ENABLE_SOFTLIMIT,
OPT_m = (1 << 5) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
OPT_o = (1 << 6) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
OPT_p = (1 << 7) * (ENABLE_SOFTLIMIT || ENABLE_CHPST),
OPT_r = (1 << 8) * ENABLE_SOFTLIMIT,
OPT_s = (1 << 9) * ENABLE_SOFTLIMIT,
OPT_t = (1 << 10) * ENABLE_SOFTLIMIT,
OPT_u = (1 << 11) * (ENABLE_CHPST || ENABLE_SETUIDGID),
OPT_U = (1 << 12) * (ENABLE_CHPST || ENABLE_ENVUIDGID),
OPT_e = (1 << 13) * (ENABLE_CHPST || ENABLE_ENVDIR),
OPT_root = (1 << 14) * ENABLE_CHPST,
OPT_n = (1 << 15) * ENABLE_CHPST,
OPT_v = (1 << 16) * ENABLE_CHPST,
OPT_P = (1 << 17) * ENABLE_CHPST,
OPT_0 = (1 << 18) * ENABLE_CHPST,
OPT_1 = (1 << 19) * ENABLE_CHPST,
OPT_2 = (1 << 20) * ENABLE_CHPST,
};
/* TODO: use recursive_action? */
static NOINLINE void edir(const char *directory_name)
{
int wdir;
DIR *dir;
struct dirent *d;
int fd;
wdir = xopen(".", O_RDONLY | O_NDELAY);
xchdir(directory_name);
dir = xopendir(".");
for (;;) {
char buf[256];
char *tail;
int size;
errno = 0;
d = readdir(dir);
if (!d) {
if (errno)
bb_perror_msg_and_die("readdir %s",
directory_name);
break;
}
if (d->d_name[0] == '.')
continue;
fd = open(d->d_name, O_RDONLY | O_NDELAY);
if (fd < 0) {
if ((errno == EISDIR) && directory_name) {
if (option_mask32 & OPT_v)
bb_perror_msg("warning: %s/%s is a directory",
directory_name, d->d_name);
continue;
}
bb_perror_msg_and_die("open %s/%s",
directory_name, d->d_name);
}
size = full_read(fd, buf, sizeof(buf)-1);
close(fd);
if (size < 0)
bb_perror_msg_and_die("read %s/%s",
directory_name, d->d_name);
if (size == 0) {
unsetenv(d->d_name);
continue;
}
buf[size] = '\n';
tail = strchr(buf, '\n');
/* skip trailing whitespace */
while (1) {
*tail = '\0';
tail--;
if (tail < buf || !isspace(*tail))
break;
}
xsetenv(d->d_name, buf);
}
closedir(dir);
xfchdir(wdir);
close(wdir);
}
static void limit(int what, long l)
{
struct rlimit r;
/* Never fails under Linux (except if you pass it bad arguments) */
getrlimit(what, &r);
if ((l < 0) || (l > r.rlim_max))
r.rlim_cur = r.rlim_max;
else
r.rlim_cur = l;
if (setrlimit(what, &r) == -1)
bb_simple_perror_msg_and_die("setrlimit");
}
int chpst_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int chpst_main(int argc UNUSED_PARAM, char **argv)
{
struct bb_uidgid_t ugid;
char *set_user = set_user; /* for compiler */
char *env_dir = env_dir;
char *root;
char *nicestr;
unsigned limita;
unsigned limitc;
unsigned limitd;
unsigned limitf;
unsigned limitl;
unsigned limitm;
unsigned limito;
unsigned limitp;
unsigned limitr;
unsigned limits;
unsigned limitt;
unsigned opt;
if ((ENABLE_CHPST && applet_name[0] == 'c')
|| (ENABLE_SOFTLIMIT && applet_name[1] == 'o')
) {
// FIXME: can we live with int-sized limits?
// can we live with 40000 days?
// if yes -> getopt converts strings to numbers for us
opt = getopt32(argv, "^+"
"a:+c:+d:+f:+l:+m:+o:+p:+r:+s:+t:+u:U:e:"
IF_CHPST("/:n:vP012")
"\0" "-1",
&limita, &limitc, &limitd, &limitf, &limitl,
&limitm, &limito, &limitp, &limitr, &limits, &limitt,
&set_user, &set_user, &env_dir
IF_CHPST(, &root, &nicestr));
argv += optind;
if (opt & OPT_m) { // -m means -asld
limita = limits = limitl = limitd = limitm;
opt |= (OPT_s | OPT_l | OPT_a | OPT_d);
}
} else {
option_mask32 = opt = 0;
argv++;
if (!*argv)
bb_show_usage();
}
// envdir?
if (ENABLE_ENVDIR && applet_name[3] == 'd') {
env_dir = *argv++;
opt |= OPT_e;
}
// setuidgid?
if (ENABLE_SETUIDGID && applet_name[1] == 'e') {
set_user = *argv++;
opt |= OPT_u;
}
// envuidgid?
if (ENABLE_ENVUIDGID && applet_name[0] == 'e' && applet_name[3] == 'u') {
set_user = *argv++;
opt |= OPT_U;
}
// we must have PROG [ARGS]
if (!*argv)
bb_show_usage();
// set limits
if (opt & OPT_d) {
#ifdef RLIMIT_DATA
limit(RLIMIT_DATA, limitd);
#else
if (opt & OPT_v)
bb_error_msg("system does not support RLIMIT_%s",
"DATA");
#endif
}
if (opt & OPT_s) {
#ifdef RLIMIT_STACK
limit(RLIMIT_STACK, limits);
#else
if (opt & OPT_v)
bb_error_msg("system does not support RLIMIT_%s",
"STACK");
#endif
}
if (opt & OPT_l) {
#ifdef RLIMIT_MEMLOCK
limit(RLIMIT_MEMLOCK, limitl);
#else
if (opt & OPT_v)
bb_error_msg("system does not support RLIMIT_%s",
"MEMLOCK");
#endif
}
if (opt & OPT_a) {
#ifdef RLIMIT_VMEM
limit(RLIMIT_VMEM, limita);
#else
#ifdef RLIMIT_AS
limit(RLIMIT_AS, limita);
#else
if (opt & OPT_v)
bb_error_msg("system does not support RLIMIT_%s",
"VMEM");
#endif
#endif
}
if (opt & OPT_o) {
#ifdef RLIMIT_NOFILE
limit(RLIMIT_NOFILE, limito);
#else
#ifdef RLIMIT_OFILE
limit(RLIMIT_OFILE, limito);
#else
if (opt & OPT_v)
bb_error_msg("system does not support RLIMIT_%s",
"NOFILE");
#endif
#endif
}
if (opt & OPT_p) {
#ifdef RLIMIT_NPROC
limit(RLIMIT_NPROC, limitp);
#else
if (opt & OPT_v)
bb_error_msg("system does not support RLIMIT_%s",
"NPROC");
#endif
}
if (opt & OPT_f) {
#ifdef RLIMIT_FSIZE
limit(RLIMIT_FSIZE, limitf);
#else
if (opt & OPT_v)
bb_error_msg("system does not support RLIMIT_%s",
"FSIZE");
#endif
}
if (opt & OPT_c) {
#ifdef RLIMIT_CORE
limit(RLIMIT_CORE, limitc);
#else
if (opt & OPT_v)
bb_error_msg("system does not support RLIMIT_%s",
"CORE");
#endif
}
if (opt & OPT_r) {
#ifdef RLIMIT_RSS
limit(RLIMIT_RSS, limitr);
#else
if (opt & OPT_v)
bb_error_msg("system does not support RLIMIT_%s",
"RSS");
#endif
}
if (opt & OPT_t) {
#ifdef RLIMIT_CPU
limit(RLIMIT_CPU, limitt);
#else
if (opt & OPT_v)
bb_error_msg("system does not support RLIMIT_%s",
"CPU");
#endif
}
if (opt & OPT_P)
setsid();
if (opt & OPT_e)
edir(env_dir);
if (opt & (OPT_u|OPT_U))
xget_uidgid(&ugid, set_user);
// chrooted jail must have /etc/passwd if we move this after chroot.
// OTOH chroot fails for non-roots.
// Solution: cache uid/gid before chroot, apply uid/gid after.
if (opt & OPT_U) {
xsetenv("GID", utoa(ugid.gid));
xsetenv("UID", utoa(ugid.uid));
}
if (opt & OPT_root) {
xchroot(root);
}
/* nice should be done before xsetuid */
if (opt & OPT_n) {
errno = 0;
if (nice(xatoi(nicestr)) == -1)
bb_simple_perror_msg_and_die("nice");
}
if (opt & OPT_u) {
if (setgroups(1, &ugid.gid) == -1)
bb_simple_perror_msg_and_die("setgroups");
xsetgid(ugid.gid);
xsetuid(ugid.uid);
}
if (opt & OPT_0)
close(STDIN_FILENO);
if (opt & OPT_1)
close(STDOUT_FILENO);
if (opt & OPT_2)
close(STDERR_FILENO);
BB_EXECVP_or_die(argv);
}
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