util: cu - micro serial console

Applications/util/Makefile.common

@@ -47,6 +47,7 @@ SRCS  = \
 	chmem.c \
 	cksum.c \
 	cp.c \
+	cu.c \
 	cut.c \
 	dd.c \
 	decomp16.c \

Applications/util/Makefile.generic

@@ -46,6 +46,7 @@ SRCS  = \
 	chmem.c \
 	cksum.c \
 	cp.c \
+	cu.c \
 	cut.c \
 	dd.c \
 	decomp16.c \

Applications/util/cu.1

@@ -0,0 +1,61 @@
+.TH cu 1 "FUZIX System Utilities" "FUZIX"
+.SH NAME
+cu \- simple serial console.
+.SH SYNOPSIS
+.B cu
+\-l device
+[\-s speed]
+[\-E escape-character]
+.SH DESCRIPTION
+Simple and minimal terminal emulator program, to use with modems and alike.
+.P
+Just like other terminal emulator progrms
+.B cu
+supports escape sequence to execute a command in
+.B cu
+itself.
+.SH OPTIONS
+.TP
+.B "-l device"
+Path to the character device.
+.B "-E escape-character"
+Set alternate escape character.
+.P
+.TP
+.B "-s speed"
+Set speed of the
+.B device
+in baud before connecting.
+
+.SH COMMANDS
+Commands are executed by first inputing
+.I escape character
+(
+.B ESC
+) which by default is
+.B ~
+
+.TP
+.B "ESC ."
+Quit program and restore
+.B device termios
+to the previous settings.
+
+.TP
+.B "ESC ESC"
+Print escape character verbatim.
+
+.P
+.I Note:
+Escape character is only acknowledged after a new line.
+
+.SH EXAMPLES
+.P
+cu -l /dev/tty2
+.P
+cu -s 300 -l /dev/tty2
+.SH BUGS
+To be found.
+.SH AUTHORS
+Yaroslav Veremenko
+.SH SEE ALSO

Applications/util/cu.c

@@ -0,0 +1,260 @@
+/* cu.c - Simple serial console.
+ *
+ * Copyright (C) 2024 Yaroslav Veremenko, All rights reserved.
+ *
+ * This file is part of FUZIX Operating System.
+ *
+ * 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, 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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include <stdio.h>
+#include <signal.h>
+#include <termios.h>
+#include <unistd.h>
+#include <stdlib.h>
+#include <fcntl.h>
+#include <string.h>
+#include <errno.h>
+#include <sys/wait.h>
+#include <getopt.h>
+
+static struct termios termsave[2];
+static struct termios termcur[2];
+static int remotefd = -1;
+static pid_t child;
+
+static int baud[] = {
+    50,     /* B50 */
+    75,     /* B75 */
+    110,    /* B110 */
+    134,    /* B134 */
+    150,    /* B150 */
+    300,    /* B300 */
+    600,    /* B600 */
+    1200,   /* B1200 */
+    2400,   /* B2400 */
+    4800,   /* B4800 */
+    9600,   /* B9600 */
+    19200,  /* B19200 */
+    38400,  /* B38400 */
+    57600,  /* B57600 */
+    115200, /* B115200 */
+};
+
+static speed_t speed[] = {
+    B50,
+    B75,
+    B110,
+    B134,
+    B150,
+    B300,
+    B600,
+    B1200,
+    B2400,
+    B4800,
+    B9600,
+    B19200,
+    B38400,
+    B57600,
+    B115200,
+};
+
+#ifndef uint_fast8_t
+#define uint_fast8_t char
+#endif
+
+#define TTY 0
+#define REMOTE 1
+
+static void term_raw(int fd, int type)
+{
+    tcgetattr(fd, &termsave[type]);
+    memcpy(&termcur[type], &termsave[type], sizeof(struct termios));
+    cfmakeraw(&termcur[type]);
+    termcur[type].c_cc[VMIN] = 1;
+    termcur[type].c_cc[VTIME] = 0;
+    tcsetattr(fd, TCSAFLUSH, &termcur[type]);
+}
+
+static void restore()
+{
+    tcsetattr(0, TCSAFLUSH, &termsave[TTY]);
+    if (remotefd >= 0)
+    {
+        tcsetattr(remotefd, TCSAFLUSH, &termsave[REMOTE]);
+        close(remotefd);
+    }
+}
+
+static void quit()
+{
+    kill(child, SIGKILL);
+    wait((int *)NULL);
+    restore();
+}
+
+static int parsespeed(char *str, speed_t *s)
+{
+    register int i;
+    register int b = atoi(optarg);
+    for (i = 0; i < sizeof(baud) / sizeof(baud[0]); i++)
+    {
+        if (baud[i] == b)
+        {
+            *s = speed[i];
+            return 1;
+        }
+    }
+    return 0;
+}
+
+static void usage()
+{
+    fputs("Usage: cu -l LINE [-s SPEED] [-E ESCCHAR]\n",
+          stderr);
+}
+
+int main(int argc, char *argv[])
+{
+    speed_t speedval = 0;
+    char escchar = '~';
+    int opt;
+    char *remotename = NULL;
+
+    if (isatty(0) != 1)
+    {
+        fputs("fd 0 is not tty\n", stderr);
+        exit(1);
+    }
+
+    while ((opt = getopt(argc, argv, "s:l:E:")) != -1)
+    {
+        switch (opt)
+        {
+        case 's':
+            if (!parsespeed(optarg, &speedval))
+            {
+                fprintf(stderr, "invalid speed: %s\n", optarg);
+                exit(1);
+                return 0;
+            }
+            break;
+        case 'l':
+            remotename = optarg;
+            break;
+        case 'E':
+            /* if arg starts with ^, then ^@=0x00 and ^Z=0x1A
+                otherwise escape char is used verbatim */
+            if (optarg[0] == '^' && (optarg[1] < 'A' || optarg[1] > 'Z') || optarg[1])
+            {
+                fprintf(stderr, "invalid char\n");
+                exit(1);
+                return 0;
+            }
+            escchar = optarg[0];
+            if (optarg[0] == '^')
+            {
+                escchar -= '@';
+            }
+            break;
+        default:
+            usage();
+            exit(1);
+            break;
+        }
+    }
+
+    if (remotename == NULL)
+    {
+        usage();
+        exit(1);
+    }
+
+    remotefd = open(remotename, O_RDWR | O_NOCTTY);
+
+    if (remotefd < 0)
+    {
+        perror(remotename);
+        exit(1);
+    }
+
+    term_raw(0, TTY);
+    term_raw(remotefd, REMOTE);
+
+    if (speedval > 0)
+    {
+        if (cfsetospeed(&termcur[REMOTE], (speed_t)speedval) < 0 ||
+            tcsetattr(remotefd, TCSAFLUSH, &termcur[REMOTE]) < 0)
+        {
+            restore();
+            perror("speed");
+            exit(1);
+        }
+    }
+
+    child = fork();
+    if (child < 0)
+    {
+        restore();
+        perror("fork");
+        exit(1);
+    }
+    if (child == 0)
+    {
+        uint_fast8_t r;
+        while (read(remotefd, &r, 1) == 1)
+        {
+            write(0, &r, 1);
+        }
+        fputs("Disconnected\r\n", stderr);
+    }
+    else
+    {
+        uint_fast8_t is_esc = 0;
+        uint_fast8_t is_nl = 1;
+        uint_fast8_t w;
+        atexit(restore);
+        char escStr[3];
+        if (escchar <= 0x1A)
+        {
+            escStr[0] = '^';
+            escStr[1] = escchar + '@';
+            escStr[2] = '\0';
+        }
+        else
+        {
+            escStr[0] = escchar;
+            escStr[1] = '\0';
+        }
+
+        fprintf(stderr, "Connected. Escape is %s\r\n", escStr);
+        while (read(0, &w, 1) == 1)
+        {
+            if (is_nl && !is_esc && w == escchar)
+            {
+                is_esc = 1;
+                continue;
+            }
+            if (is_esc && w == '.')
+            {
+                break;
+            }
+            is_nl = w == '\r' || w == '\n';
+            is_esc = 0;
+            write(remotefd, &w, 1);
+        }
+        quit();
+    }
+}

Applications/util/fuzix-util.pkg

@@ -118,6 +118,7 @@ f 0755 /bin/uniq        uniq
 f 0755 /bin/uptime      uptime
 f 0755 /bin/uud         uud
 f 0755 /bin/uue         uue
+f 0755 /bin/cu          cu
 f 0755 /bin/vile        vile
 l /bin/vile /bin/vi
 f 0755 /bin/wc          wc
@@ -138,3 +139,4 @@ f 0655 /usr/man/man1/mv.1        mv.1
 f 0655 /usr/man/man1/ps.1        ps.1
 f 0655 /usr/man/man1/size.1      size.1
 f 0655 /usr/man/man1/substroot.1 substroot.1
+f 0655 /usr/man/man1/cu.1        cu.1