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libbb: split update_utmp from login/getty in preparation to use it for telnetd

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function                                             old     new   delta
update_utent                                           -     339    +339
login_main                                          1498    1128    -370
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/1 up/down: 339/-370)          Total: -31 bytes

function                                             old     new   delta
update_utmp                                          246     337     +91
login_main                                          1128    1140     +12
getty_main                                          1908    1918     +10
...
update_utent                                         339       -    -339
------------------------------------------------------------------------------
(add/remove: 1/1 grow/shrink: 5/6 up/down: 119/-368)         Total: -249 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2010-04-05 03:18:40 +02:00
parent 4c721049c3
commit 37f5bef63c
7 changed files with 117 additions and 159 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
coreutils/who.c
View File

@ -16,7 +16,7 @@
*
*----------------------------------------------------------------------
*/
/* BB_AUDIT SUSv3 _NOT_ compliant -- missing options -b, -d, -H, -l, -m, -p, -q, -r, -s, -t, -T, -u; Missing argument 'file'. */
/* BB_AUDIT SUSv3 _NOT_ compliant -- missing options -b, -d, -l, -m, -p, -q, -r, -s, -t, -T, -u; Missing argument 'file'. */
#include "libbb.h"
#include <utmp.h>

6
include/libbb.h
View File

@ -796,6 +796,12 @@ void die_if_bad_username(const char* name) FAST_FUNC;
#define die_if_bad_username(name) ((void)(name))
#endif
#if ENABLE_FEATURE_UTMP
void FAST_FUNC update_utmp(int new_type, const char *short_tty, const char *username, const char *opt_host);
#else
# define update_utmp(new_type, short_tty, username, opt_host) ((void)0)
#endif
int execable_file(const char *name) FAST_FUNC;
char *find_execable(const char *filename, char **PATHp) FAST_FUNC;
int exists_execable(const char *filename) FAST_FUNC;

1
init/halt.c
View File

@ -30,7 +30,6 @@ static void write_wtmp(void)
if (uname(&uts) == 0)
safe_strncpy(utmp.ut_host, uts.release, sizeof(utmp.ut_host));
updwtmp(bb_path_wtmp_file, &utmp);
}
#else
#define write_wtmp() ((void)0)

2
libbb/Kbuild
View File

@ -120,6 +120,8 @@ lib-y += xgethostbyname.o
lib-y += xreadlink.o
lib-y += xrealloc_vector.o
lib-$(CONFIG_FEATURE_UTMP) += utmp.o
# A mix of optimizations (why build stuff we know won't be used)
# and objects which may fail to build (SELinux on selinux-less system)
lib-$(CONFIG_SELINUX) += selinux_common.o

92
libbb/utmp.c Normal file
View File

@ -0,0 +1,92 @@
/* vi: set sw=4 ts=4: */
/*
* utmp/wtmp support routines.
*
* Copyright (C) 2010 Denys Vlasenko
*
* Licensed under GPL version 2, see file LICENSE in this tarball for details.
*/
#include "libbb.h"
#include <utmp.h>
static void touch(const char *filename)
{
if (access(filename, R_OK | W_OK) == -1)
close(open(filename, O_WRONLY | O_CREAT, 0664));
}
/*
* Read "man utmp" to make sense out of it.
*/
void FAST_FUNC update_utmp(int new_type, const char *short_tty, const char *username, const char *opt_host)
{
struct utmp utent;
struct utmp *ut;
pid_t pid;
touch(_PATH_UTMP);
utmpname(_PATH_UTMP);
setutent();
pid = getpid();
/* Did init/getty/telnetd/sshd/... create an entry for us?
* It should be (new_type-1), but we'd also reuse
* any other potentially stale xxx_PROCESS entry */
while ((ut = getutent()) != NULL) {
if (ut->ut_pid == pid
// && ut->ut_line[0]
&& ut->ut_id[0] /* must have nonzero id */
&& ( ut->ut_type == INIT_PROCESS
|| ut->ut_type == LOGIN_PROCESS
|| ut->ut_type == USER_PROCESS
|| ut->ut_type == DEAD_PROCESS
)
) {
utent = *ut; /* struct copy */
if (ut->ut_type >= new_type) {
/* Stale record. Nuke hostname */
memset(utent.ut_host, 0, sizeof(utent.ut_host));
}
/* NB: pututline (see later) searches for matching utent
* using getutid(utent) - we must not change ut_id
* if we want *exactly this* record to be overwritten!
*/
break;
}
}
endutent();
if (!ut) {
/* Didn't find anything, create new one */
memset(&utent, 0, sizeof(utent));
utent.ut_pid = pid;
/* Invent our own ut_id. ut_id is only 4 chars wide.
* Try to fit something remotely meaningful... */
if (short_tty[0] == 'p') {
/* if "ptyXXX", map to "pXXX" */
/* if "pts/XX", map to "p/XX" */
utent.ut_id[0] = 'p';
strncpy(utent.ut_id + 1, short_tty + 3, sizeof(utent.ut_id)-1);
} else {
/* assuming it's "ttyXXXX", map to "XXXX" */
strncpy(utent.ut_id, short_tty + 3, sizeof(utent.ut_id));
}
}
utent.ut_type = new_type;
safe_strncpy(utent.ut_line, short_tty, sizeof(utent.ut_line));
safe_strncpy(utent.ut_user, username, sizeof(utent.ut_user));
if (opt_host)
safe_strncpy(utent.ut_host, opt_host, sizeof(utent.ut_host));
utent.ut_tv.tv_sec = time(NULL);
/* Update, or append new one */
setutent();
pututline(&utent);
endutent();
#if ENABLE_FEATURE_WTMP
touch(bb_path_wtmp_file);
updwtmp(bb_path_wtmp_file, &utent);
#endif
}

61
loginutils/getty.c
View File

@ -19,7 +19,7 @@
#include <syslog.h>
#if ENABLE_FEATURE_UTMP
#include <utmp.h> /* updwtmp() */
#include <utmp.h> /* LOGIN_PROCESS */
#endif
#ifndef IUCLC
@ -575,61 +575,6 @@ static void termios_final(struct options *op, struct termios *tp, struct chardat
ioctl_or_perror_and_die(0, TCSETS, tp, "%s: TCSETS", op->tty);
}
#if ENABLE_FEATURE_UTMP
static void touch(const char *filename)
{
if (access(filename, R_OK | W_OK) == -1)
close(open(filename, O_WRONLY | O_CREAT, 0664));
}
/* update_utmp - update our utmp entry */
static NOINLINE void update_utmp(const char *line, char *fakehost)
{
struct utmp ut;
struct utmp *utp;
int mypid = getpid();
/* In case we won't find an entry below... */
memset(&ut, 0, sizeof(ut));
safe_strncpy(ut.ut_id, line + 3, sizeof(ut.ut_id));
/*
* The utmp file holds miscellaneous information about things started by
* /sbin/init and other system-related events. Our purpose is to update
* the utmp entry for the current process, in particular the process type
* and the tty line we are listening to. Return successfully only if the
* utmp file can be opened for update, and if we are able to find our
* entry in the utmp file.
*/
touch(_PATH_UTMP);
utmpname(_PATH_UTMP);
setutent();
while ((utp = getutent()) != NULL) {
if (utp->ut_type == INIT_PROCESS && utp->ut_pid == mypid) {
memcpy(&ut, utp, sizeof(ut));
break;
}
}
strcpy(ut.ut_user, "LOGIN");
safe_strncpy(ut.ut_line, line, sizeof(ut.ut_line));
if (fakehost)
safe_strncpy(ut.ut_host, fakehost, sizeof(ut.ut_host));
ut.ut_tv.tv_sec = time(NULL);
ut.ut_type = LOGIN_PROCESS;
ut.ut_pid = mypid;
pututline(&ut);
endutent();
#if ENABLE_FEATURE_WTMP
touch(bb_path_wtmp_file);
updwtmp(bb_path_wtmp_file, &ut);
#endif
}
#endif /* CONFIG_FEATURE_UTMP */
int getty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int getty_main(int argc UNUSED_PARAM, char **argv)
{
@ -715,10 +660,8 @@ int getty_main(int argc UNUSED_PARAM, char **argv)
tcsetpgrp(0, getpid());
#endif
#if ENABLE_FEATURE_UTMP
/* Update the utmp file. This tty is ours now! */
update_utmp(options.tty, fakehost);
#endif
update_utmp(LOGIN_PROCESS, options.tty, "LOGIN", fakehost);
/* Initialize the termios settings (raw mode, eight-bit, blocking i/o). */
debug("calling termios_init\n");

112
loginutils/login.c
View File

@ -2,25 +2,26 @@
/*
* Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
*/
#include "libbb.h"
#include <syslog.h>
#include <utmp.h>
#if ENABLE_FEATURE_UTMP
# include <utmp.h> /* USER_PROCESS */
#endif
#include <sys/resource.h>
#if ENABLE_SELINUX
#include <selinux/selinux.h> /* for is_selinux_enabled() */
#include <selinux/get_context_list.h> /* for get_default_context() */
#include <selinux/flask.h> /* for security class definitions */
# include <selinux/selinux.h> /* for is_selinux_enabled() */
# include <selinux/get_context_list.h> /* for get_default_context() */
# include <selinux/flask.h> /* for security class definitions */
#endif
#if ENABLE_PAM
/* PAM may include <locale.h>. We may need to undefine bbox's stub define: */
#undef setlocale
# undef setlocale
/* For some obscure reason, PAM is not in pam/xxx, but in security/xxx.
* Apparently they like to confuse people. */
#include <security/pam_appl.h>
#include <security/pam_misc.h>
# include <security/pam_appl.h>
# include <security/pam_misc.h>
static const struct pam_conv conv = {
misc_conv,
NULL
@ -36,87 +37,6 @@ enum {
static char* short_tty;
#if ENABLE_FEATURE_UTMP
/* vv Taken from tinylogin utmp.c vv */
/*
* read_or_build_utent - see if utmp file is correct for this process
*
* System V is very picky about the contents of the utmp file
* and requires that a slot for the current process exist.
* The utmp file is scanned for an entry with the same process
* ID. If no entry exists the process exits with a message.
*
* The "picky" flag is for network and other logins that may
* use special flags. It allows the pid checks to be overridden.
* This means that getty should never invoke login with any
* command line flags.
*/
static void read_or_build_utent(struct utmp *utptr, int run_by_root)
{
struct utmp *ut;
pid_t pid = getpid();
setutent();
/* First, try to find a valid utmp entry for this process. */
/* If there is one, just use it. */
while ((ut = getutent()) != NULL) {
if (ut->ut_pid == pid && ut->ut_line[0] && ut->ut_id[0]
&& (ut->ut_type == LOGIN_PROCESS || ut->ut_type == USER_PROCESS)
) {
*utptr = *ut; /* struct copy */
if (run_by_root) /* why only for root? */
memset(utptr->ut_host, 0, sizeof(utptr->ut_host));
return;
}
}
// Why? Do we require non-root to exec login from another
// former login process (e.g. login shell)? Some login's have
// login shells as children, so it won't work...
// if (!run_by_root)
// bb_error_msg_and_die("no utmp entry found");
/* Otherwise create a new one. */
memset(utptr, 0, sizeof(*utptr));
utptr->ut_type = LOGIN_PROCESS;
utptr->ut_pid = pid;
strncpy(utptr->ut_line, short_tty, sizeof(utptr->ut_line));
/* This one is only 4 chars wide. Try to fit something
* remotely meaningful by skipping "tty"... */
strncpy(utptr->ut_id, short_tty + 3, sizeof(utptr->ut_id));
strncpy(utptr->ut_user, "LOGIN", sizeof(utptr->ut_user));
utptr->ut_tv.tv_sec = time(NULL);
}
/*
* write_utent - put a USER_PROCESS entry in the utmp file
*
* write_utent changes the type of the current utmp entry to
* USER_PROCESS. the wtmp file will be updated as well.
*/
static void write_utent(struct utmp *utptr, const char *username)
{
utptr->ut_type = USER_PROCESS;
strncpy(utptr->ut_user, username, sizeof(utptr->ut_user));
utptr->ut_tv.tv_sec = time(NULL);
/* other fields already filled in by read_or_build_utent above */
setutent();
pututline(utptr);
endutent();
#if ENABLE_FEATURE_WTMP
if (access(bb_path_wtmp_file, R_OK|W_OK) == -1) {
close(creat(bb_path_wtmp_file, 0664));
}
updwtmp(bb_path_wtmp_file, utptr);
#endif
}
#else /* !ENABLE_FEATURE_UTMP */
#define read_or_build_utent(utptr, run_by_root) ((void)0)
#define write_utent(utptr, username) ((void)0)
#endif /* !ENABLE_FEATURE_UTMP */
#if ENABLE_FEATURE_NOLOGIN
static void die_if_nologin(void)
{
@ -144,7 +64,7 @@ static void die_if_nologin(void)
exit(EXIT_FAILURE);
}
#else
static ALWAYS_INLINE void die_if_nologin(void) {}
# define die_if_nologin() ((void)0)
#endif
#if ENABLE_FEATURE_SECURETTY && !ENABLE_PAM
@ -286,11 +206,10 @@ int login_main(int argc UNUSED_PARAM, char **argv)
unsigned opt;
int count = 0;
struct passwd *pw;
char *opt_host = opt_host; /* for compiler */
char *opt_host = NULL;
char *opt_user = opt_user; /* for compiler */
char *full_tty;
IF_SELINUX(security_context_t user_sid = NULL;)
IF_FEATURE_UTMP(struct utmp utent;)
#if ENABLE_PAM
int pamret;
pam_handle_t *pamh;
@ -334,10 +253,7 @@ int login_main(int argc UNUSED_PARAM, char **argv)
if (strncmp(full_tty, "/dev/", 5) == 0)
short_tty += 5;
read_or_build_utent(&utent, run_by_root);
if (opt & LOGIN_OPT_h) {
IF_FEATURE_UTMP(safe_strncpy(utent.ut_host, opt_host, sizeof(utent.ut_host));)
if (opt_host) {
fromhost = xasprintf(" on '%s' from '%s'", short_tty, opt_host);
} else {
fromhost = xasprintf(" on '%s'", short_tty);
@ -461,8 +377,6 @@ int login_main(int argc UNUSED_PARAM, char **argv)
if (pw->pw_uid != 0)
die_if_nologin();
write_utent(&utent, username);
IF_SELINUX(initselinux(username, full_tty, &user_sid));
/* Try these, but don't complain if they fail.
@ -470,6 +384,8 @@ int login_main(int argc UNUSED_PARAM, char **argv)
fchown(0, pw->pw_uid, pw->pw_gid);
fchmod(0, 0600);
update_utmp(USER_PROCESS, short_tty, username, run_by_root ? opt_host : NULL);
/* We trust environment only if we run by root */
if (ENABLE_LOGIN_SCRIPTS && run_by_root)
run_login_script(pw, full_tty);