telnetd: write LOGIN/DEAD_PROCESS utmp records. Closes bug 1363
authorDenys Vlasenko <vda.linux@googlemail.com>
Mon, 5 Apr 2010 20:10:38 +0000 (22:10 +0200)
committerDenys Vlasenko <vda.linux@googlemail.com>
Mon, 5 Apr 2010 20:10:38 +0000 (22:10 +0200)
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>
include/libbb.h
init/halt.c
libbb/utmp.c
loginutils/getty.c
loginutils/login.c
miscutils/last.c
networking/telnetd.c

index ea61701b799fd5b7f34535b74a58d039b7506a2c..f3121eb47f65a28c60447c10edbfbc80050e30d8 100644 (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;
index a3459ee488aad3af6e0ee3f96c77242da73eda07..f1bb2c4a85fee769a90b0b76bba19000c4d0bc32 100644 (file)
@@ -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
index 06b939b9d84548d2e9f0be8393719d19e93a5398..d6ba336e3e36725544ce41ab8094039e68a4377b 100644 (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));
-       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
 }
index 8d1d5254e3510b76b178c36b20e23d134f64f87c..d032357e2401a931c9061dcdd3bbba3e9e879f4a 100644 (file)
@@ -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");
index 4a820379d27633ce20fd8b7e748a25285c3f9d36..bf21d6121c62b45c8b935205ddcfe9abf9a1580f 100644 (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)
index 6e3ed9093322084a38f228954815f787d18fa7dd..55c03ae41048990b83e225c36a5ff39937360681 100644 (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;
                        }
index cab94f0f7eacc3be75d093d31b1b57b49ac5f5e3..b3e66eb4b081012d8a89a5df88a3c0470c596d53 100644 (file)
  * 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;
        }