Merge branch 'master' of git+ssh://vda@busybox.net/var/lib/git/busybox

[oweals/busybox.git] / shell / cttyhack.c

diff --git a/shell/cttyhack.c b/shell/cttyhack.c
index cdd0ed1d6dd39fc9605344af957da0fb52c43776..bde2acdc93db82012a7ef4c61428d2b20454e554 100644 (file)
--- a/shell/cttyhack.c
+++ b/shell/cttyhack.c
@@ -1,16 +1,18 @@
-/* This code is adapted from busybox project
- *
+/* vi: set sw=4 ts=4: */
+/*
  * Licensed under GPLv2
+ *
+ * Copyright (c) 2007 Denys Vlasenko <vda.linux@googlemail.com>
  */
 #include "libbb.h"
 
 /* From <linux/vt.h> */
 struct vt_stat {
-       unsigned short v_active;        /* active vt */
-       unsigned short v_signal;        /* signal to send */
-       unsigned short v_state; /* vt bitmask */
+       unsigned short v_active;        /* active vt */
+       unsigned short v_signal;        /* signal to send */
+       unsigned short v_state;         /* vt bitmask */
 };
-enum { VT_GETSTATE = 0x5603 }; /* get global vt state info */
+enum { VT_GETSTATE = 0x5603 }; /* get global vt state info */
 
 /* From <linux/serial.h> */
 struct serial_struct {
@@ -26,8 +28,8 @@ struct serial_struct {
        char    io_type;
        char    reserved_char[1];
        int     hub6;
-       unsigned short  closing_wait; /* time to wait before closing */
-       unsigned short  closing_wait2; /* no longer used... */
+       unsigned short  closing_wait;   /* time to wait before closing */
+       unsigned short  closing_wait2;  /* no longer used... */
        unsigned char   *iomem_base;
        unsigned short  iomem_reg_shift;
        unsigned int    port_high;
@@ -35,8 +37,8 @@ struct serial_struct {
        int     reserved[1];
 };
 
-int cttyhack_main(int argc, char **argv) ATTRIBUTE_NORETURN;
-int cttyhack_main(int argc, char **argv)
+int cttyhack_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int cttyhack_main(int argc UNUSED_PARAM, char **argv)
 {
        int fd;
        char console[sizeof(int)*3 + 16];
@@ -51,23 +53,34 @@ int cttyhack_main(int argc, char **argv)
        }
 
        strcpy(console, "/dev/tty");
-       if (ioctl(0, TIOCGSERIAL, &u.sr) == 0) {
-               /* this is a serial console */
-               sprintf(console + 8, "S%d", u.sr.line);
-       } else if (ioctl(0, VT_GETSTATE, &u.vt) == 0) {
-               /* this is linux virtual tty */
-               sprintf(console + 8, "S%d" + 1, u.vt.v_active);
-       }
-
-       if (console[8]) {
-               fd = xopen(console, O_RDWR);
-               //bb_error_msg("switching to '%s'", console);
-               dup2(fd, 0);
-               dup2(fd, 1);
-               dup2(fd, 2);
-               while (fd > 2) close(fd--);
+       fd = open(console, O_RDWR);
+       if (fd >= 0) {
+               /* We already have ctty, nothing to do */
+               close(fd);
+       } else {
+               /* We don't have ctty (or don't have "/dev/tty" node...) */
+               if (ioctl(0, TIOCGSERIAL, &u.sr) == 0) {
+                       /* this is a serial console */
+                       sprintf(console + 8, "S%d", u.sr.line);
+               } else if (ioctl(0, VT_GETSTATE, &u.vt) == 0) {
+                       /* this is linux virtual tty */
+                       sprintf(console + 8, "S%d" + 1, u.vt.v_active);
+               }
+               if (console[8]) {
+                       fd = xopen(console, O_RDWR);
+                       //bb_error_msg("switching to '%s'", console);
+                       dup2(fd, 0);
+                       dup2(fd, 1);
+                       dup2(fd, 2);
+                       while (fd > 2)
+                               close(fd--);
+                       /* Some other session may have it as ctty,
+                        * steal it from them:
+                        */
+                       ioctl(0, TIOCSCTTY, 1);
+               }
        }
 
-       execvp(argv[0], argv);
-       bb_perror_msg_and_die("cannot exec '%s'", argv[0]);
+       BB_EXECVP(argv[0], argv);
+       bb_perror_msg_and_die("can't execute '%s'", argv[0]);
 }