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telnetd: write LOGIN/DEAD_PROCESS utmp records. Closes bug 1363

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function                                             old     new   delta
write_new_utmp                                         -     253    +253
skip_dev_pfx                                           -      30     +30
handle_sigchld                                        42      72     +30
telnetd_main                                        1650    1673     +23
make_new_session                                     415     438     +23
...
login_main                                          1140    1148      +8
update_utmp                                          337     313     -24
write_wtmp                                           220     154     -66
------------------------------------------------------------------------------
(add/remove: 2/0 grow/shrink: 11/6 up/down: 406/-115)         Total: ~291 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
This commit is contained in:
Denys Vlasenko 2010-04-05 22:10:38 +02:00
parent 37f5bef63c
commit 3a41611bc5
7 changed files with 134 additions and 56 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
include/libbb.h
View File

@ -797,9 +797,11 @@ void die_if_bad_username(const char* name) FAST_FUNC;
#endif
#if ENABLE_FEATURE_UTMP
void FAST_FUNC update_utmp(int new_type, const char *short_tty, const char *username, const char *opt_host);
void FAST_FUNC write_new_utmp(pid_t pid, int new_type, const char *tty_name, const char *username, const char *hostname);
void FAST_FUNC update_utmp(pid_t pid, int new_type, const char *tty_name, const char *username, const char *hostname);
#else
# define update_utmp(new_type, short_tty, username, opt_host) ((void)0)
# define write_new_utmp(pid, new_type, tty_name, username, hostname) ((void)0)
# define update_utmp(pid, new_type, tty_name, username, hostname) ((void)0)
#endif
int execable_file(const char *name) FAST_FUNC;

13
init/halt.c
View File

@ -18,16 +18,17 @@ static void write_wtmp(void)
{
struct utmp utmp;
struct utsname uts;
if (access(bb_path_wtmp_file, R_OK|W_OK) == -1) {
/* "man utmp" says wtmp file should *not* be created automagically */
/*if (access(bb_path_wtmp_file, R_OK|W_OK) == -1) {
close(creat(bb_path_wtmp_file, 0664));
}
}*/
memset(&utmp, 0, sizeof(utmp));
utmp.ut_tv.tv_sec = time(NULL);
safe_strncpy(utmp.ut_user, "shutdown", UT_NAMESIZE);
strcpy(utmp.ut_user, "shutdown"); /* it is wide enough */
utmp.ut_type = RUN_LVL;
safe_strncpy(utmp.ut_id, "~~", sizeof(utmp.ut_id));
safe_strncpy(utmp.ut_line, "~~", UT_LINESIZE);
if (uname(&uts) == 0)
utmp.ut_id[0] = '~'; utmp.ut_id[1] = '~'; /* = strcpy(utmp.ut_id, "~~"); */
utmp.ut_line[0] = '~'; utmp.ut_line[1] = '~'; /* = strcpy(utmp.ut_line, "~~"); */
uname(&uts);
safe_strncpy(utmp.ut_host, uts.release, sizeof(utmp.ut_host));
updwtmp(bb_path_wtmp_file, &utmp);
}

121
libbb/utmp.c
View File

@ -15,37 +15,87 @@ static void touch(const char *filename)
close(open(filename, O_WRONLY | O_CREAT, 0664));
}
// TODO: move to libbb
static const char* skip_dev_pfx(const char *tty_name)
{
if (strncmp(tty_name, "/dev/", 5) == 0)
tty_name += 5;
return tty_name;
}
void FAST_FUNC write_new_utmp(pid_t pid, int new_type, const char *tty_name, const char *username, const char *hostname)
{
struct utmp utent;
char *id;
unsigned width;
memset(&utent, 0, sizeof(utent));
utent.ut_pid = pid;
utent.ut_type = new_type;
tty_name = skip_dev_pfx(tty_name);
safe_strncpy(utent.ut_line, tty_name, sizeof(utent.ut_line));
if (username)
safe_strncpy(utent.ut_user, username, sizeof(utent.ut_user));
if (hostname)
safe_strncpy(utent.ut_host, hostname, sizeof(utent.ut_host));
utent.ut_tv.tv_sec = time(NULL);
/* Invent our own ut_id. ut_id is only 4 chars wide.
* Try to fit something remotely meaningful... */
id = utent.ut_id;
width = sizeof(utent.ut_id);
if (tty_name[0] == 'p') {
/* if "ptyXXX", map to "pXXX" */
/* if "pts/XX", map to "p/XX" */
*id++ = 'p';
width--;
} /* else: usually it's "ttyXXXX", map to "XXXX" */
if (strlen(tty_name) > 3)
tty_name += 3;
strncpy(id, tty_name, width);
touch(_PATH_UTMP);
//utmpname(_PATH_UTMP);
setutent();
/* Append new one (hopefully, unless we collide on ut_id) */
pututline(&utent);
endutent();
#if ENABLE_FEATURE_WTMP
/* "man utmp" says wtmp file should *not* be created automagically */
/*touch(bb_path_wtmp_file);*/
updwtmp(bb_path_wtmp_file, &utent);
#endif
}
/*
* 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)
void FAST_FUNC update_utmp(pid_t pid, int new_type, const char *tty_name, const char *username, const char *hostname)
{
struct utmp utent;
struct utmp *ut;
pid_t pid;
struct utmp *utp;
touch(_PATH_UTMP);
utmpname(_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
while ((utp = getutent()) != NULL) {
if (utp->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
&& utp->ut_id[0] /* must have nonzero id */
&& ( utp->ut_type == INIT_PROCESS
|| utp->ut_type == LOGIN_PROCESS
|| utp->ut_type == USER_PROCESS
|| utp->ut_type == DEAD_PROCESS
)
) {
utent = *ut; /* struct copy */
if (ut->ut_type >= new_type) {
if (utp->ut_type >= new_type) {
/* Stale record. Nuke hostname */
memset(utent.ut_host, 0, sizeof(utent.ut_host));
memset(utp->ut_host, 0, sizeof(utp->ut_host));
}
/* NB: pututline (see later) searches for matching utent
* using getutid(utent) - we must not change ut_id
@ -54,39 +104,38 @@ void FAST_FUNC update_utmp(int new_type, const char *short_tty, const char *user
break;
}
}
endutent();
//endutent(); - no need, pututline can deal with (and actually likes)
//the situation when utmp file is positioned on found record
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));
}
if (!utp) {
if (new_type != DEAD_PROCESS)
write_new_utmp(pid, new_type, tty_name, username, hostname);
else
endutent();
return;
}
/* Make a copy. We can't use *utp, pututline's internal getutid
* will overwrite it before it is used! */
utent = *utp;
utent.ut_type = new_type;
safe_strncpy(utent.ut_line, short_tty, sizeof(utent.ut_line));
if (tty_name)
safe_strncpy(utent.ut_line, skip_dev_pfx(tty_name), sizeof(utent.ut_line));
if (username)
safe_strncpy(utent.ut_user, username, sizeof(utent.ut_user));
if (opt_host)
safe_strncpy(utent.ut_host, opt_host, sizeof(utent.ut_host));
if (hostname)
safe_strncpy(utent.ut_host, hostname, sizeof(utent.ut_host));
utent.ut_tv.tv_sec = time(NULL);
/* Update, or append new one */
setutent();
//setutent();
pututline(&utent);
endutent();
#if ENABLE_FEATURE_WTMP
touch(bb_path_wtmp_file);
/* "man utmp" says wtmp file should *not* be created automagically */
/*touch(bb_path_wtmp_file);*/
updwtmp(bb_path_wtmp_file, &utent);
#endif
}

6
loginutils/getty.c
View File

@ -579,6 +579,7 @@ int getty_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int getty_main(int argc UNUSED_PARAM, char **argv)
{
int n;
pid_t pid;
char *fakehost = NULL; /* Fake hostname for ut_host */
char *logname; /* login name, given to /bin/login */
/* Merging these into "struct local" may _seem_ to reduce
@ -651,17 +652,18 @@ int getty_main(int argc UNUSED_PARAM, char **argv)
/* tcgetattr() + error check */
ioctl_or_perror_and_die(0, TCGETS, &termios, "%s: TCGETS", options.tty);
pid = getpid();
#ifdef __linux__
// FIXME: do we need this? Otherwise "-" case seems to be broken...
// /* Forcibly make fd 0 our controlling tty, even if another session
// * has it as a ctty. (Another session loses ctty). */
// ioctl(0, TIOCSCTTY, (void*)1);
/* Make ourself a foreground process group within our session */
tcsetpgrp(0, getpid());
tcsetpgrp(0, pid);
#endif
/* Update the utmp file. This tty is ours now! */
update_utmp(LOGIN_PROCESS, options.tty, "LOGIN", fakehost);
update_utmp(pid, LOGIN_PROCESS, options.tty, "LOGIN", fakehost);
/* Initialize the termios settings (raw mode, eight-bit, blocking i/o). */
debug("calling termios_init\n");

2
loginutils/login.c
View File

@ -384,7 +384,7 @@ 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);
update_utmp(getpid(), 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)

3
miscutils/last.c
View File

@ -92,7 +92,8 @@ int last_main(int argc UNUSED_PARAM, char **argv UNUSED_PARAM)
goto next;
}
if (ut.ut_type != DEAD_PROCESS
&& ut.ut_user[0] && ut.ut_line[0]
&& ut.ut_user[0]
&& ut.ut_line[0]
) {
ut.ut_type = USER_PROCESS;
}

29
networking/telnetd.c
View File

@ -20,7 +20,6 @@
* Vladimir Oleynik <dzo@simtreas.ru> 2001
* Set process group corrections, initial busybox port
*/
#define DEBUG 0
#include "libbb.h"
@ -32,6 +31,11 @@
#endif
#include <arpa/telnet.h>
#if ENABLE_FEATURE_UTMP
# include <utmp.h> /* LOGIN_PROCESS */
#endif
struct tsession {
struct tsession *next;
pid_t shell_pid;
@ -319,7 +323,11 @@ make_new_session(
xopen(tty_name, O_RDWR); /* becomes our ctty */
xdup2(0, 1);
xdup2(0, 2);
tcsetpgrp(0, getpid()); /* switch this tty's process group to us */
pid = getpid();
tcsetpgrp(0, pid); /* switch this tty's process group to us */
//TODO: fetch remote addr via getpeername (see ftpd.c)
write_new_utmp(pid, LOGIN_PROCESS, tty_name, /*username:*/ "LOGIN", /*hostname:*/ NULL);
/* The pseudo-terminal allocated to the client is configured to operate
* in cooked mode, and with XTABS CRMOD enabled (see tty(4)) */
@ -358,12 +366,13 @@ make_new_session(
static void
free_session(struct tsession *ts)
{
struct tsession *t = G.sessions;
struct tsession *t;
if (option_mask32 & OPT_INETD)
exit(EXIT_SUCCESS);
/* Unlink this telnet session from the session list */
t = G.sessions;
if (t == ts)
G.sessions = ts->next;
else {
@ -414,6 +423,7 @@ static void handle_sigchld(int sig UNUSED_PARAM)
{
pid_t pid;
struct tsession *ts;
int save_errno = errno;
/* Looping: more than one child may have exited */
while (1) {
@ -424,11 +434,22 @@ static void handle_sigchld(int sig UNUSED_PARAM)
while (ts) {
if (ts->shell_pid == pid) {
ts->shell_pid = -1;
// man utmp:
// When init(8) finds that a process has exited, it locates its utmp entry
// by ut_pid, sets ut_type to DEAD_PROCESS, and clears ut_user, ut_host
// and ut_time with null bytes.
// [same applies to other processes which maintain utmp entries, like telnetd]
//
// We do not bother actually clearing fields:
// it might be interesting to know who was logged in and from where
update_utmp(pid, DEAD_PROCESS, /*tty_name:*/ NULL, /*username:*/ NULL, /*hostname:*/ NULL);
break;
}
ts = ts->next;
}
}
errno = save_errno;
}
int telnetd_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
@ -689,6 +710,8 @@ int telnetd_main(int argc UNUSED_PARAM, char **argv)
ts = next;
continue;
kill_session:
if (ts->shell_pid > 0)
update_utmp(ts->shell_pid, DEAD_PROCESS, /*tty_name:*/ NULL, /*username:*/ NULL, /*hostname:*/ NULL);
free_session(ts);
ts = next;
}