login: fork & session initialization refactoring

Signed-off-by: Karel Zak <kzak@redhat.com>

diff --git a/login-utils/login.c b/login-utils/login.c
index 5ad5444f08587b00084809746e467a748ad1b54f..877d1984c1d55ecb7f5c10d50924acd3ee7efefa 100644 (file)
--- a/login-utils/login.c
+++ b/login-utils/login.c
@@ -117,7 +117,9 @@ struct login_context {
  * This bounds the time given to login.  Not a define so it can
  * be patched on machines where it's too small.
  */
-int timeout = LOGIN_TIMEOUT;
+static int timeout = LOGIN_TIMEOUT;
+static int child_pid = 0;
+static volatile int got_sig = 0;
 
 static void timedout(int);
 static void sigint(int);
@@ -334,9 +336,6 @@ static void log_btmp(struct login_context *cxt)
        updwtmp(_PATH_BTMP, &ut);
 }
 
-static int child_pid = 0;
-static volatile int got_sig = 0;
-
 /*
  * This handler allows to inform a shell about signals to login. If you have
  * (root) permissions you can kill all login childrent by one signal to login
@@ -822,6 +821,106 @@ static int get_hushlogin_status(struct passwd *pwd)
        return 0;
 }
 
+/*
+ * Detach the controlling terminal, fork, restore syslog stuff and create a new
+ * session.
+ */
+static void fork_session(struct login_context *cxt)
+{
+       struct sigaction sa, oldsa_hup, oldsa_term;
+
+       signal(SIGALRM, SIG_DFL);
+       signal(SIGQUIT, SIG_DFL);
+       signal(SIGTSTP, SIG_IGN);
+
+       memset(&sa, 0, sizeof(sa));
+       sa.sa_handler = SIG_IGN;
+       sigaction(SIGINT, &sa, NULL);
+
+       sigaction(SIGHUP, &sa, &oldsa_hup);     /* ignore when TIOCNOTTY */
+
+       /*
+        * detach the controlling tty
+        * -- we needn't the tty in parent who waits for child only.
+        *    The child calls setsid() that detach from the tty as well.
+        */
+       ioctl(0, TIOCNOTTY, NULL);
+
+       /*
+        * We have care about SIGTERM, because leave PAM session without
+        * pam_close_session() is pretty bad thing.
+        */
+       sa.sa_handler = sig_handler;
+       sigaction(SIGHUP, &sa, NULL);
+       sigaction(SIGTERM, &sa, &oldsa_term);
+
+       closelog();
+
+       /*
+        * We must fork before setuid() because we need to call
+        * pam_close_session() as root.
+        */
+       child_pid = fork();
+       if (child_pid < 0) {
+               /*
+                * fork() error
+                */
+               warn(_("fork failed"));
+
+               pam_setcred(cxt->pamh, PAM_DELETE_CRED);
+               pam_end(cxt->pamh, pam_close_session(cxt->pamh, 0));
+               exit(EXIT_FAILURE);
+       }
+
+       if (child_pid) {
+               /*
+                * parent - wait for child to finish, then cleanup session
+                */
+               close(0);
+               close(1);
+               close(2);
+               sa.sa_handler = SIG_IGN;
+               sigaction(SIGQUIT, &sa, NULL);
+               sigaction(SIGINT, &sa, NULL);
+
+               /* wait as long as any child is there */
+               while (wait(NULL) == -1 && errno == EINTR) ;
+               openlog("login", LOG_ODELAY, LOG_AUTHPRIV);
+
+               pam_setcred(cxt->pamh, PAM_DELETE_CRED);
+               pam_end(cxt->pamh, pam_close_session(cxt->pamh, 0));
+               exit(EXIT_SUCCESS);
+       }
+
+       /*
+        * child
+        */
+       sigaction(SIGHUP, &oldsa_hup, NULL);            /* restore old state */
+       sigaction(SIGTERM, &oldsa_term, NULL);
+       if (got_sig)
+               exit(EXIT_FAILURE);
+
+       /*
+        * Problem: if the user's shell is a shell like ash that doesnt do
+        * setsid() or setpgrp(), then a ctrl-\, sending SIGQUIT to every
+        * process in the pgrp, will kill us.
+        */
+
+       /* start new session */
+       setsid();
+
+       /* make sure we have a controlling tty */
+       open_tty(cxt->tty_path);
+       openlog("login", LOG_ODELAY, LOG_AUTHPRIV);     /* reopen */
+
+       /*
+        * TIOCSCTTY: steal tty from other process group.
+        */
+       if (ioctl(0, TIOCSCTTY, 1))
+               syslog(LOG_ERR, _("TIOCSCTTY failed: %m"));
+       signal(SIGINT, SIG_DFL);
+}
+
 int main(int argc, char **argv)
 {
        extern int optind;
@@ -836,7 +935,6 @@ int main(int argc, char **argv)
        char *buff;
        int childArgc = 0;
        int retcode;
-       struct sigaction sa, oldsa_hup, oldsa_term;
 
        char *pwdbuf = NULL;
        struct passwd *pwd = NULL, _pwd;
@@ -1120,97 +1218,11 @@ int main(int argc, char **argv)
 #endif
        }
 
-       signal(SIGALRM, SIG_DFL);
-       signal(SIGQUIT, SIG_DFL);
-       signal(SIGTSTP, SIG_IGN);
-
-       memset(&sa, 0, sizeof(sa));
-       sa.sa_handler = SIG_IGN;
-       sigaction(SIGINT, &sa, NULL);
-
-       sigaction(SIGHUP, &sa, &oldsa_hup);     /* ignore when TIOCNOTTY */
-
        /*
-        * detach the controlling tty
-        * -- we needn't the tty in parent who waits for child only.
-        *    The child calls setsid() that detach from the tty as well.
+        * Detach the controlling terminal, fork() and create, new session
+        * and reinilizalize syslog stuff.
         */
-       ioctl(0, TIOCNOTTY, NULL);
-
-       /*
-        * We have care about SIGTERM, because leave PAM session without
-        * pam_close_session() is pretty bad thing.
-        */
-       sa.sa_handler = sig_handler;
-       sigaction(SIGHUP, &sa, NULL);
-       sigaction(SIGTERM, &sa, &oldsa_term);
-
-       closelog();
-
-       /*
-        * We must fork before setuid() because we need to call
-        * pam_close_session() as root.
-        */
-
-       child_pid = fork();
-       if (child_pid < 0) {
-               /*
-                * fork() error
-                */
-               warn(_("fork failed"));
-
-               pam_setcred(cxt.pamh, PAM_DELETE_CRED);
-               pam_end(cxt.pamh, pam_close_session(cxt.pamh, 0));
-               exit(EXIT_FAILURE);
-       }
-
-       if (child_pid) {
-               /*
-                * parent - wait for child to finish, then cleanup session
-                */
-               close(0);
-               close(1);
-               close(2);
-               sa.sa_handler = SIG_IGN;
-               sigaction(SIGQUIT, &sa, NULL);
-               sigaction(SIGINT, &sa, NULL);
-
-               /* wait as long as any child is there */
-               while (wait(NULL) == -1 && errno == EINTR) ;
-               openlog("login", LOG_ODELAY, LOG_AUTHPRIV);
-
-               pam_setcred(cxt.pamh, PAM_DELETE_CRED);
-               pam_end(cxt.pamh, pam_close_session(cxt.pamh, 0));
-               exit(EXIT_SUCCESS);
-       }
-
-       /* child */
-
-       /* restore to old state */
-       sigaction(SIGHUP, &oldsa_hup, NULL);
-       sigaction(SIGTERM, &oldsa_term, NULL);
-       if (got_sig)
-               exit(EXIT_FAILURE);
-
-       /*
-        * Problem: if the user's shell is a shell like ash that doesnt do
-        * setsid() or setpgrp(), then a ctrl-\, sending SIGQUIT to every
-        * process in the pgrp, will kill us.
-        */
-
-       /* start new session */
-       setsid();
-
-       /* make sure we have a controlling tty */
-       open_tty(cxt.tty_path);
-       openlog("login", LOG_ODELAY, LOG_AUTHPRIV);     /* reopen */
-
-       /*
-        * TIOCSCTTY: steal tty from other process group.
-        */
-       if (ioctl(0, TIOCSCTTY, 1))
-               syslog(LOG_ERR, _("TIOCSCTTY failed: %m"));
-       signal(SIGINT, SIG_DFL);
+       fork_session(&cxt);
 
        /* discard permissions last so can't get killed and drop core */
        if (setuid(pwd->pw_uid) < 0 && pwd->pw_uid) {