[PATCH] Use stdin instead of opening /dev/tty in nmap_tty.cc

The attached patch uses stdin instead of opening /dev/tty for run-time
interaction. It makes it shorter and, except for handling non-blocking
mode, very simple.

I assume the Cygwin part of tty_getchar() is still required.

Everything I added in the patch is in POSIX.1, so it should be very
portable to non-Windows platforms (and probably more portable than
opening /dev/tty, etc.).

Also, really, tty_done() probably isn't needed because we're modifying
stdin and not a terminal, so when we exit (the only time it's called)
it's not going to affect anything. But leaving it shouldn't hurt either.

I've tested it quite a bit and everything seems to work fine.

It's a diff against 4.20ALPHA8

Thanks,
Kris Katterjohn

--- x/nmap_tty.cc 2006-10-01 09:44:40.000000000 -0500
+++ y/nmap_tty.cc 2006-10-03 22:33:40.000000000 -0500
@@ -143,44 +143,33 @@ extern int tcsetattr(int fd, int actions
 #endif
 #endif
 
-static int tty_fd = 0;
+static int stdinflags;
 static struct termios saved_ti;
 
 static int tty_getchar()
 {
- int c, numChars;
+ int c;
 #ifdef __CYGWIN32__
         fd_set set;
         struct timeval tv;
-#endif
         
- if (tty_fd && tcgetpgrp(tty_fd) == getpid()) {
-
- // This is so that when the terminal has been disconnected, it will be reconnected when possible. If it slows things down, just remove it
- // tty_init();
-
-#ifdef __CYGWIN32__
- FD_ZERO(&set); FD_SET(tty_fd, &set);
- tv.tv_sec = 0; tv.tv_usec = 0;
- if (select(tty_fd + 1, &set, NULL, NULL, &tv) <= 0)
- return -1;
+ FD_ZERO(&set); FD_SET(STDIN_FILENO, &set);
+ tv.tv_sec = 0; tv.tv_usec = 0;
+ if (select(STDIN_FILENO + 1, &set, NULL, NULL, &tv) <= 0)
+ return -1;
 #endif
- c = 0;
- numChars = read(tty_fd, &c, 1);
- if (numChars > 0) return c;
- }
+ c = getchar();
+
+ if (c != EOF)
+ return c;
 
         return -1;
 }
 
 static void tty_done()
 {
- if (!tty_fd) return;
-
- tcsetattr(tty_fd, TCSANOW, &saved_ti);
-
- close(tty_fd);
- tty_fd = 0;
+ fcntl(STDIN_FILENO, F_SETFL, stdinflags & ~O_NONBLOCK);
+ tcsetattr(STDIN_FILENO, TCSANOW, &saved_ti);
 }
 
 /*
@@ -192,23 +181,20 @@ void tty_init()
 {
         struct termios ti;
 
- if (tty_fd)
+ if (!isatty(STDIN_FILENO))
                 return;
 
- if ((tty_fd = open("/dev/tty", O_RDONLY | O_NONBLOCK)) < 0) return;
-
-#ifndef __CYGWIN32__
- if (tcgetpgrp(tty_fd) != getpid()) {
- close(tty_fd); return;
- }
-#endif
+ stdinflags = fcntl(STDIN_FILENO, F_GETFL);
+ if (!(stdinflags & O_NONBLOCK))
+ if (fcntl(STDIN_FILENO, F_SETFL, stdinflags | O_NONBLOCK) == -1)
+ return;
 
- tcgetattr(tty_fd, &ti);
+ tcgetattr(STDIN_FILENO, &ti);
         saved_ti = ti;
         ti.c_lflag &= ~(ICANON | ECHO);
         ti.c_cc[VMIN] = 1;
         ti.c_cc[VTIME] = 0;
- tcsetattr(tty_fd, TCSANOW, &ti);
+ tcsetattr(STDIN_FILENO, TCSAFLUSH, &ti);
 
         atexit(tty_done);
 }

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Received on Oct 03 2006