Initial import

src/tty.c

@@ -0,0 +1,181 @@
+/*
+ * Go TTY - The Really Simple Terminal Application
+ *
+ * Copyright (c) 2014  Martin Lund
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+ * 02110-1301, USA.
+ */
+
+#include <stdio.h>
+#include <unistd.h>
+#include <string.h>
+#include <stdlib.h>
+#include <limits.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+#include <termios.h>
+#include <stdbool.h>
+#include "gotty/tty.h"
+#include "gotty/print.h"
+#include "gotty/options.h"
+
+#define MAX(x, y) (((x) > (y)) ? (x) : (y))
+
+#define CTRLG 0x07
+#define CTRLQ 0x11
+
+static int fd;
+struct termios stdio, old_stdio, old_tio;
+
+void configure_stdout(void)
+{
+    /* Save current stdout settings */
+    if (tcgetattr(STDOUT_FILENO, &old_stdio) < 0)
+    {
+        printf("Error: Saving current stdio settings failed\n");
+        exit(EXIT_FAILURE);
+    }
+
+    /* Prepare stdio settings */
+    bzero(&stdio, sizeof(stdio));
+
+    /* Control, input, output, local modes for stdio */
+    stdio.c_cflag = 0;
+    stdio.c_iflag = 0;
+    stdio.c_oflag = 0;
+    stdio.c_lflag = 0;
+
+    /* Control characters */
+    stdio.c_cc[VTIME] = 0; /* Inter-character timer unused */
+    stdio.c_cc[VMIN]  = 1; /* Blocking read until 1 character received */
+
+    /* Activate stdio settings */
+    tcsetattr(STDOUT_FILENO, TCSANOW, &stdio);
+    tcsetattr(STDOUT_FILENO, TCSAFLUSH, &stdio);
+}
+
+void restore(void)
+{
+    static int i=0;
+
+    tcflush(STDOUT_FILENO, TCIOFLUSH);
+    tcsetattr(STDOUT_FILENO, TCSANOW, &old_stdio);
+    tcsetattr(STDOUT_FILENO, TCSAFLUSH, &old_stdio);
+
+    tcsetattr(fd, TCSANOW, &old_tio);
+    tcsetattr(fd, TCSAFLUSH, &old_tio);
+
+    gotty_printf("Disconnected\n");
+}
+
+int connect_tty(void)
+{
+    int    console = 0;
+    fd_set rdfs;           /* Read file descriptor set */
+    int    maxfd;          /* Maximum file desciptor used */
+    char   c, c0 = 0, c1 = 0;
+    static bool first = true;
+    int    status;
+
+    /* Open tty device */
+    fd = open(option.device, O_RDWR | O_NOCTTY ); 
+    if (fd <0)
+    {
+        perror(option.device);
+        exit(EXIT_FAILURE);
+    }
+
+    /* Make sure device is of tty type */
+    if (!isatty(fd))
+    {
+        printf("Error: Not a tty device");
+        exit(EXIT_FAILURE);
+    }
+
+    gotty_printf("Connected");
+
+    /* Save current port settings */
+    if (tcgetattr(fd, &old_tio) < 0)
+    {
+        printf("Error: Saving current port settings failed\n");
+        exit(EXIT_FAILURE);
+    }
+
+    /* Make sure we restore settings on exit */
+    if (first)
+    {
+        atexit(&restore);
+        first = false;
+    }
+
+    /* Control, input, output, local modes for tty device */
+    option.tio.c_cflag |= CLOCAL | CREAD;
+    option.tio.c_oflag = 0;
+    option.tio.c_lflag = 0;
+
+    /* Control characters */
+    option.tio.c_cc[VTIME] = 0; /* Inter-character timer unused */
+    option.tio.c_cc[VMIN]  = 1; /* Blocking read until 1 character received */
+
+    /* Activate new port settings */
+    tcsetattr(fd, TCSANOW, &option.tio);
+    tcsetattr(fd, TCSAFLUSH, &option.tio);
+
+    maxfd = MAX(fd, console) + 1;  /* Maximum bit entry (fd) to test */
+
+    /* Input loop */
+    while (true)
+    {
+        FD_ZERO(&rdfs);
+        FD_SET(fd, &rdfs);
+        FD_SET(console, &rdfs);
+
+        /* Block until input becomes available */
+        select(maxfd, &rdfs, NULL, NULL, NULL);
+        if (FD_ISSET(fd, &rdfs))
+        {
+            /* Input from tty device ready */
+            if (read(fd, &c, 1) > 0)
+            {
+                /* Print received tty character to stdout */
+                putchar(c);
+                fflush(stdout);
+            } else
+            {
+                if (!option.no_autoconnect)
+                    gotty_printf("Disconnected");
+                return(EXIT_FAILURE);
+            }
+        }
+        if (FD_ISSET(console, &rdfs))
+        {
+            /* Input from stdin ready */
+            status = read(console, &c, 1);
+
+            /* Exit upon ctrl-g ctrl-q sequence */
+            c1 = c0;
+            c0 = c;
+            if ((c0 == CTRLQ) && (c1 == CTRLG))
+                exit(EXIT_SUCCESS);
+
+            /* Forward input to tty device */
+            status = write(fd, &c, 1);
+        }
+    }
+
+    return(EXIT_SUCCESS);
+}