[PATCH] Check tcgetattr return value in init/init.c

[Timur R. Mustafin]

Hello, busybox developers!

I found uninitialized variable use in /set_sane_term()/. It calls 
/tcgetattr()/ function that should set /&tty /structure, but 
/tcgetattr()/ can fail. During a fail /&tty/ structure stay 
uninitialized. Patch checks return values of /tcgetattr()/, 
/tcsetattr()/ and makes /set_sane_term()/ function error-returning.

Regards,
     Timur.

diff --git a/init/init.c b/init/init.c
index 87086b4..a837652 100644
--- a/init/init.c
+++ b/init/init.c
@@ -343,11 +343,13 @@ static void console_init(void)

  /* Set terminal settings to reasonable defaults.
   * NB: careful, we can be called after vfork! */
-static void set_sane_term(void)
+static int set_sane_term(void)
  {
         struct termios tty;

-       tcgetattr(STDIN_FILENO, &tty);
+       /* tcgetattr() returns 0 on success, -1 on failure */
+       if (tcgetattr(STDIN_FILENO, &tty) == -1)
+               return 0;

         /* set control chars */
         tty.c_cc[VINTR] = 3;    /* C-c */
@@ -381,7 +383,8 @@ static void set_sane_term(void)
         /* local modes */
         tty.c_lflag = ISIG | ICANON | ECHO | ECHOE | ECHOK | ECHOCTL | 
ECHOKE | IEXTEN;

-       tcsetattr_stdin_TCSANOW(&tty);
+       /* tcsetattr() returns 0 on success, -1 on failure */
+       return !tcsetattr_stdin_TCSANOW(&tty);
  }

  /* Open the new terminal device.
@@ -405,8 +408,7 @@ static int open_stdio_to_tty(const char* tty_name)
                 dup2(STDIN_FILENO, STDOUT_FILENO);
                 dup2(STDIN_FILENO, STDERR_FILENO);
         }
-       set_sane_term();
-       return 1; /* success */
+       return set_sane_term();
  }

  static void reset_sighandlers_and_unblock_sigs(void)
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