su: consolidate tty name usage

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

diff --git a/login-utils/su-common.c b/login-utils/su-common.c
index c647d60ff6a76dcdd25805ca2f9860e7295e088b..d725cd23cb73a7e4ba8b0ad033d80d39a5e9835e 100644 (file)
--- a/login-utils/su-common.c
+++ b/login-utils/su-common.c
@@ -87,7 +87,11 @@ struct su_context {
        pam_handle_t    *pamh;                  /* PAM handler */
        struct pam_conv conv;                   /* PAM conversation */
 
+       const char      *tty_name;              /* tty_path without /dev prefix */
+       const char      *tty_number;            /* end of the tty_path */
+
        unsigned int runuser :1,                /* flase=su, true=runuser */
+                    isterm :1,                 /* is stdin terminal? */
                     fast_startup :1,           /* pass the `-f' option to the subshell. */
                     simulate_login :1,         /* simulate a login instead of just starting a shell. */
                     change_environment :1,     /* change some environment vars to indicate the user su'd to.*/
@@ -130,13 +134,20 @@ current_getpwuid(void)
        return errno == 0 ? getpwuid(ruid) : NULL;
 }
 
+
+static void init_tty(struct su_context *su)
+{
+       su->isterm = isatty(STDIN_FILENO) ? 1 : 0;
+       if (su->isterm)
+               get_terminal_name(NULL, &su->tty_name, &su->tty_number);
+}
+
 /* Log the fact that someone has run su to the user given by PW;
    if SUCCESSFUL is true, they gave the correct password, etc.  */
 
-static void
-log_syslog(struct su_context *su, struct passwd const *pw, bool successful)
+static void log_syslog(struct su_context *su, struct passwd const *pw, bool successful)
 {
-       const char *new_user, *old_user, *tty;
+       const char *new_user, *old_user;
 
        new_user = pw->pw_name;
        /* The utmp entry (via getlogin) is probably the best way to identify
@@ -149,37 +160,32 @@ log_syslog(struct su_context *su, struct passwd const *pw, bool successful)
                old_user = pwd ? pwd->pw_name : "";
        }
 
-       if (get_terminal_name(NULL, &tty, NULL) != 0 || !tty)
-               tty = "none";
-
        openlog(program_invocation_short_name, 0, LOG_AUTH);
        syslog(LOG_NOTICE, "%s(to %s) %s on %s",
               successful ? "" :
               su->runuser ? "FAILED RUNUSER " : "FAILED SU ",
-              new_user, old_user, tty);
+              new_user, old_user,
+              su->tty_name ? : "none");
        closelog();
 }
 
 /*
  * Log failed login attempts in _PATH_BTMP if that exists.
  */
-static void log_btmp(struct passwd const * const pw)
+static void log_btmp(struct su_context *su, struct passwd const * const pw)
 {
        struct utmpx ut;
        struct timeval tv;
-       const char *tty_name, *tty_num;
 
        memset(&ut, 0, sizeof(ut));
-
        strncpy(ut.ut_user,
                pw && pw->pw_name ? pw->pw_name : "(unknown)",
                sizeof(ut.ut_user));
 
-       get_terminal_name(NULL, &tty_name, &tty_num);
-       if (tty_num)
-               xstrncpy(ut.ut_id, tty_num, sizeof(ut.ut_id));
-       if (tty_name)
-               xstrncpy(ut.ut_line, tty_name, sizeof(ut.ut_line));
+       if (su->tty_number)
+               xstrncpy(ut.ut_id, su->tty_number, sizeof(ut.ut_id));
+       if (su->tty_name)
+               xstrncpy(ut.ut_line, su->tty_name, sizeof(ut.ut_line));
 
        gettimeofday(&tv, NULL);
        ut.ut_tv.tv_sec = tv.tv_sec;
@@ -237,7 +243,7 @@ static void supam_export_environment(struct su_context *su)
 static void supam_authenticate(struct su_context *su, const struct passwd *pw)
 {
        const struct passwd *lpw = NULL;
-       const char *cp, *srvname = NULL;
+       const char *srvname = NULL;
        int retval;
 
        srvname = su->runuser ?
@@ -248,14 +254,8 @@ static void supam_authenticate(struct su_context *su, const struct passwd *pw)
        if (is_pam_failure(retval))
                goto done;
 
-       if (isatty(0) && (cp = ttyname(0)) != NULL) {
-               const char *tty;
-
-               if (strncmp(cp, "/dev/", 5) == 0)
-                       tty = cp + 5;
-               else
-                       tty = cp;
-               retval = pam_set_item(su->pamh, PAM_TTY, tty);
+       if (su->tty_name) {
+               retval = pam_set_item(su->pamh, PAM_TTY, su->tty_name);
                if (is_pam_failure(retval))
                        goto done;
        }
@@ -294,7 +294,7 @@ static void supam_authenticate(struct su_context *su, const struct passwd *pw)
        if (is_pam_failure(retval)) {
                const char *msg;
 
-               log_btmp(pw);
+               log_btmp(su, pw);
 
                msg = pam_strerror(su->pamh, retval);
                pam_end(su->pamh, retval);
@@ -857,6 +857,7 @@ su_main(int argc, char **argv, int mode)
                     _("only root can specify alternative groups"));
 
        logindefs_set_loader(load_config, (void *) su);
+       init_tty(su);
 
        pw = getpwnam(new_user);
        if (!(pw && pw->pw_name && pw->pw_name[0] && pw->pw_dir && pw->pw_dir[0]