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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
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33
networking/telnetd.c
View File

@@ -20,18 +20,22 @@
* Vladimir Oleynik <dzo@simtreas.ru> 2001
* Set process group corrections, initial busybox port
*/
#define DEBUG 0
#include "libbb.h"
#include <syslog.h>
#if DEBUG
#define TELCMDS
#define TELOPTS
# define TELCMDS
# define TELOPTS
#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;
}