[git commit master] telnetd: write LOGIN/DEAD_PROCESS utmp records. Closes bug 1363
Denys Vlasenko
vda.linux at googlemail.com
Mon Apr 5 20:10:38 UTC 2010
commit: http://git.busybox.net/busybox/commit/?id=3a41611bc5ddeda6044e1f1e2956174b25389ce0
branch: http://git.busybox.net/busybox/commit/?id=refs/heads/master
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 at googlemail.com>
---
include/libbb.h | 6 ++-
init/halt.c | 15 +++---
libbb/utmp.c | 123 +++++++++++++++++++++++++++++++++++---------------
loginutils/getty.c | 8 ++-
loginutils/login.c | 2 +-
miscutils/last.c | 3 +-
networking/telnetd.c | 33 +++++++++++--
7 files changed, 134 insertions(+), 56 deletions(-)
diff --git a/include/libbb.h b/include/libbb.h
index ea61701..f3121eb 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -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;
diff --git a/init/halt.c b/init/halt.c
index a3459ee..f1bb2c4 100644
--- a/init/halt.c
+++ b/init/halt.c
@@ -18,17 +18,18 @@ 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)
- safe_strncpy(utmp.ut_host, uts.release, sizeof(utmp.ut_host));
+ 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);
}
#else
diff --git a/libbb/utmp.c b/libbb/utmp.c
index 06b939b..d6ba336 100644
--- a/libbb/utmp.c
+++ b/libbb/utmp.c
@@ -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));
- 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 (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 (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
}
diff --git a/loginutils/getty.c b/loginutils/getty.c
index 8d1d525..d032357 100644
--- a/loginutils/getty.c
+++ b/loginutils/getty.c
@@ -19,7 +19,7 @@
#include <syslog.h>
#if ENABLE_FEATURE_UTMP
-#include <utmp.h> /* LOGIN_PROCESS */
+# include <utmp.h> /* LOGIN_PROCESS */
#endif
#ifndef IUCLC
@@ -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");
diff --git a/loginutils/login.c b/loginutils/login.c
index 4a82037..bf21d61 100644
--- a/loginutils/login.c
+++ b/loginutils/login.c
@@ -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)
diff --git a/miscutils/last.c b/miscutils/last.c
index 6e3ed90..55c03ae 100644
--- a/miscutils/last.c
+++ b/miscutils/last.c
@@ -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;
}
diff --git a/networking/telnetd.c b/networking/telnetd.c
index cab94f0..b3e66eb 100644
--- a/networking/telnetd.c
+++ b/networking/telnetd.c
@@ -20,18 +20,22 @@
* Vladimir Oleynik <dzo at 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;
}
--
1.6.3.3
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