Sulogin: enforce reconnection of stdin/stdout/stderr if a device

was specified.

doc/Changelog

@@ -28,6 +28,8 @@ sysvinit (2.89dsf) UNRELEASED; urgency=low
     otherwise initialize SELinux and load the policy. Patch from
     Petter Reinholdtsen.
   * Make quotes visible in example of the manual page of fstab-decode
+  * Sulogin: enforce reconnection of stdin/stdout/stderr if a device
+    was specified.
 
   [ Petter Reinholdtsen ]
   * Next release will be 2.89dsf.

src/consoles.c

@@ -225,17 +225,23 @@ void consalloc(char * name)
  * /dev/console if but only if /dev/console is used.  On Linux
  * this can be more than one device, e.g. a serial line as well
  * as a virtual console as well as a simple printer.
+ *
+ * Returns 1 if stdout and stderr should be reconnected and 0
+ * otherwise.
  */
-void detect_consoles(const char *device, int fallback)
+int detect_consoles(const char *device, int fallback)
 {
-	int fd;
+	int fd, ret = 0;
 #ifdef __linux__
 	char *attrib, *cmdline;
 	FILE *fc;
 #endif
 	if (!device || *device == '\0')
 		fd = dup(fallback);
-	else	fd = open(device, O_RDWR|O_NONBLOCK|O_NOCTTY|O_CLOEXEC);
+	else {
+		fd = open(device, O_RDWR|O_NONBLOCK|O_NOCTTY|O_CLOEXEC);
+		ret = 1;
+	}
 
 	if (fd >= 0) {
 		DIR *dir;
@@ -250,6 +256,9 @@ void detect_consoles(const char *device, int fallback)
 			goto fallback;
 		}
 		comparedev = st.st_rdev;
+
+		if (ret && (fstat(fallback, &st) < 0 || comparedev != st.st_rdev))
+			dup2(fd, fallback);
 #ifdef __linux__
 		/*
 		 * Check if the device detection for Linux system console should be used.
@@ -294,7 +303,7 @@ void detect_consoles(const char *device, int fallback)
 		closedir(dir);
 		if (!consoles)
 			goto fallback;
-		return;
+		return ret;
 	}
 #ifdef __linux__
 console:
@@ -325,7 +334,7 @@ console:
 		}
 		closedir(dir);
 		fclose(fc);
-		return;
+		return ret;
 	}
 	/*
 	 * Detection of devices used for Linux system console using
@@ -363,7 +372,7 @@ console:
 		free(attrib);
 		if (!consoles)
 			goto fallback;
-		return;
+		return ret;
 
 	}
 	/*
@@ -471,12 +480,12 @@ console:
 			if (consoles) {
 				if (!device || *device == '\0')
 					consoles->fd = fallback;
-				return;
+				return ret;
 			}
 #endif
 			goto fallback;
 		}
-		return;
+		return ret;
 	}
 #endif /* __linux __ */
 fallback:
@@ -494,4 +503,5 @@ fallback:
 		if (consoles)
 			consoles->fd = fallback;
 	}
+	return ret;
 }

src/consoles.h

@@ -45,4 +45,4 @@ struct console {
 	struct console *next;
 };
 extern struct console *consoles;
-extern void detect_consoles(const char *, int);
+extern int detect_consoles(const char *, int);

src/sulogin.c

@@ -841,6 +841,7 @@ int main(int argc, char **argv)
 	char *tty = NULL;
 	struct passwd *pwd;
 	int c, status = 0;
+	int reconnect = 0;
 	int opt_e = 0;
 	struct console *con;
 	pid_t pid;
@@ -854,7 +855,7 @@ int main(int argc, char **argv)
 	}
 
 	/*
-	 *	See if we have a timeout flag.
+	 * See if we have a timeout flag.
 	 */
 	opterr = 0;
 	while((c = getopt(argc, argv, "ept:")) != EOF) switch(c) {
@@ -884,7 +885,7 @@ int main(int argc, char **argv)
 	saved_sighup  = signal(SIGHUP,  SIG_IGN);
 
 	/*
-	 *	See if we need to open an other tty device.
+	 * See if we need to open an other tty device.
 	 */
 	if (optind < argc)
 		tty = argv[optind];
@@ -892,9 +893,10 @@ int main(int argc, char **argv)
 		tty = getenv("CONSOLE");
 
 	/*
-	 *	Detect possible consoles, use stdin as fallback.
+	 * Detect possible consoles, use stdin as fallback.
+	 * If an optional tty is given, reconnect it to stdin.
 	 */
-	detect_consoles(tty, 0);
+	reconnect = detect_consoles(tty, 0);
 
 	/*
 	 * Should not happen
@@ -906,6 +908,17 @@ int main(int argc, char **argv)
 		exit(1);
 	}
 
+	/*
+	 * If previous stdin was not the speified tty and therefore reconnected
+	 * to the specified tty also reconnect stdout and stderr.
+	 */
+	if (reconnect) {
+		if (isatty(1) == 0)
+			dup2(0, 1);
+		if (isatty(2) == 0)
+			dup2(0, 2);
+	}
+
 	/*
 	 *	Get the root password.
 	 */
@@ -967,6 +980,7 @@ int main(int argc, char **argv)
 					break;
 				}
 				fprintf(stderr, "Login incorrect.\n\r");
+				sleep(3);
 			}
 			if (alarm_rised) {
 				tcfinal(con);