claenups for previous commit

[oweals/busybox.git] / console-tools / setlogcons.c

diff --git a/console-tools/setlogcons.c b/console-tools/setlogcons.c
index 90f24ce9ce97ca67e31300d0c68c51fe29925029..0fad6600aa4d348c7bfd6d971d08c855b132d42c 100644 (file)
--- a/console-tools/setlogcons.c
+++ b/console-tools/setlogcons.c
@@ -6,26 +6,61 @@
  *
  * Based on setlogcons (kbd-1.12) by Andries E. Brouwer
  *
- * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
  */
+//config:config SETLOGCONS
+//config:      bool "setlogcons (1.8 kb)"
+//config:      default y
+//config:      select PLATFORM_LINUX
+//config:      help
+//config:      This program redirects the output console of kernel messages.
 
-#include "busybox.h"
+//applet:IF_SETLOGCONS(APPLET_NOEXEC(setlogcons, setlogcons, BB_DIR_USR_SBIN, BB_SUID_DROP, setlogcons))
 
-extern int setlogcons_main(int argc, char **argv)
+//kbuild:lib-$(CONFIG_SETLOGCONS) += setlogcons.o
+
+//usage:#define setlogcons_trivial_usage
+//usage:       "[N]"
+//usage:#define setlogcons_full_usage "\n\n"
+//usage:       "Pin kernel output to VT console N. Default:0 (do not pin)"
+
+// Comment from kernel source:
+/* ...
+ * By default, the kernel messages are always printed on the current virtual
+ * console. However, the user may modify that default with the
+ * TIOCL_SETKMSGREDIRECT ioctl call.
+ *
+ * This function sets the kernel message console to be @new. It returns the old
+ * virtual console number. The virtual terminal number 0 (both as parameter and
+ * return value) means no redirection (i.e. always printed on the currently
+ * active console).
+ */
+
+#include "libbb.h"
+
+int setlogcons_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int setlogcons_main(int argc UNUSED_PARAM, char **argv)
 {
+       char *devname;
        struct {
                char fn;
                char subarg;
-       } arg;
-
-       arg.fn = 11;    /* redirect kernel messages */
-       arg.subarg = 0; /* to specified console (current as default) */
+       } arg = {
+               11, /* redirect kernel messages (TIOCL_SETKMSGREDIRECT) */
+               0
+       };
 
-       if (argc == 2)
-               arg.subarg = atoi(argv[1]);
+       if (argv[1])
+               arg.subarg = xatou_range(argv[1], 0, 63);
 
-       if (ioctl(xopen(VC_1, O_RDONLY), TIOCLINUX, &arg))
-               bb_perror_msg_and_die("TIOCLINUX");
+       /* Can just call it on "/dev/tty1" always, but...
+        * in my testing, inactive (never opened) VTs are not
+        * redirected to, despite ioctl not failing.
+        *
+        * By using "/dev/ttyN", ensure it is activated.
+        */
+       devname = xasprintf("/dev/tty%u", arg.subarg);
+       xioctl(xopen(devname, O_RDONLY), TIOCLINUX, &arg);
 
-       return 0;
+       return EXIT_SUCCESS;
 }