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microcom: allow for specifying the escape character #46

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Merged
merged 1 commit into from
Jun 13, 2025
Merged

microcom: allow for specifying the escape character #46

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5 changes: 3 additions & 2 deletions commands.c
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Original file line number Diff line number Diff line change
Expand Up @@ -155,7 +155,8 @@ static int cmd_quit(int argc, char *argv[])

static int cmd_sendescape(int argc, char *argv[])
{
ios->write(ios, "\x1c", 1);
unsigned char tmp = CTRL(escape_char);
ios->write(ios, &tmp, 1);
return 0;
}

Expand Down Expand Up @@ -234,7 +235,7 @@ static struct cmd cmds[] = {
}, {
.name = "sendescape",
.fn = cmd_sendescape,
.info = "send a Ctrl-\\",
.info = "send the escape sequence",
}, {
.name = "quit",
.fn = cmd_quit,
Expand Down
5 changes: 5 additions & 0 deletions microcom.1
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Expand Up @@ -14,6 +14,8 @@ microcom \- A minimalistic terminal program
.IR host : port ]
.RB [\| \-s
.IR speed \|]
.RB [\| \-e
.IR escape-char \|]
.br
.B microcom -c
.IB interface : rx_id : tx_id
Expand Down Expand Up @@ -65,6 +67,9 @@ work in telnet (rfc2217) mode.
.BI \-c\ interface\fB:\fIrx_id\fB:\fItx_id\fR,\ \fI \-\-can= interface\fB:\fIrx_id\fB:\fItx_id
work in CAN mode (default: \fBcan0:200:200\fR)
.TP
.BI \-e\ escape-character \fR,\ \fB\-\-escape-char= char
use specified escape charater with Ctrl (default \fB\\\fR).
.TP
.BR -h ", " \-\-help
Show help.

Expand Down
18 changes: 14 additions & 4 deletions microcom.c
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Expand Up @@ -101,12 +101,14 @@ void main_usage(int exitcode, char *str, char *dev)
" -l, --logfile=<logfile> log output to <logfile>\n"
" -o, --listenonly Do not modify local terminal, do not send input\n"
" from stdin\n"
" -a, --answerback=<str> specify the answerback string sent as response to\n"
" -a, --answerback=<str> specify the answerback string sent as response to\n"
" an ENQ (ASCII 0x05) Character\n"
" -e, --escape-char=<chr> escape charater to use with Ctrl (%c)\n"
" -v, --version print version string\n"
" -h, --help This help\n",
DEFAULT_DEVICE, DEFAULT_BAUDRATE,
DEFAULT_CAN_INTERFACE, DEFAULT_CAN_ID, DEFAULT_CAN_ID);
DEFAULT_CAN_INTERFACE, DEFAULT_CAN_ID, DEFAULT_CAN_ID,
DEFAULT_ESCAPE_CHAR);
fprintf(stderr, "Exitcode %d - %s %s\n\n", exitcode, str, dev);
exit(exitcode);
}
Expand All @@ -115,6 +117,7 @@ int opt_force = 0;
unsigned long current_speed = DEFAULT_BAUDRATE;
int current_flow = FLOW_NONE;
int listenonly = 0;
char escape_char = DEFAULT_ESCAPE_CHAR;

int main(int argc, char *argv[])
{
Expand All @@ -141,7 +144,7 @@ int main(int argc, char *argv[])
{ },
};

while ((opt = getopt_long(argc, argv, "hp:s:t:c:dfl:oi:a:v", long_options, NULL)) != -1) {
while ((opt = getopt_long(argc, argv, "hp:s:t:c:dfl:oi:a:e:v", long_options, NULL)) != -1) {
switch (opt) {
case '?':
main_usage(1, "", "");
Expand Down Expand Up @@ -182,6 +185,13 @@ int main(int argc, char *argv[])
case 'a':
answerback = optarg;
break;
case 'e':
if (strlen(optarg) != 1) {
fprintf(stderr, "Option -e requires a single character argument.\n");
exit(EXIT_FAILURE);
}
escape_char = *optarg;
break;
}
}

Expand Down Expand Up @@ -229,7 +239,7 @@ int main(int argc, char *argv[])
ios->set_flow(ios, current_flow);

if (!listenonly) {
printf("Escape character: Ctrl-\\\n");
printf("Escape character: Ctrl-%c\n", escape_char);
printf("Type the escape character to get to the prompt.\n");

/* Now deal with the local terminal side */
Expand Down
3 changes: 3 additions & 0 deletions microcom.h
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Expand Up @@ -29,6 +29,7 @@
#include <stdbool.h>
#include <signal.h>
#include <string.h>
#include <sys/ttydefaults.h>
#include <termios.h>
#include <unistd.h>
#include <assert.h>
Expand All @@ -37,6 +38,7 @@
#define DEFAULT_DEVICE "/dev/ttyS0"
#define DEFAULT_CAN_INTERFACE "can0"
#define DEFAULT_CAN_ID (0x200)
#define DEFAULT_ESCAPE_CHAR ('\\')

struct ios_ops {
ssize_t (*write)(struct ios_ops *, const void *buf, size_t count);
Expand Down Expand Up @@ -73,6 +75,7 @@ extern int debug;
extern int opt_force;
extern int listenonly;
extern char *answerback;
extern char escape_char;

struct cmd {
char *name;
Expand Down
2 changes: 1 addition & 1 deletion mux.c
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Expand Up @@ -73,7 +73,7 @@ static void cook_buf(struct ios_ops *ios, unsigned char *buf, int num)
while (current < num) { /* big while loop, to process all the charactes in buffer */

/* look for the next escape character (Ctrl-\) */
while ((current < num) && (buf[current] != 28))
while ((current < num) && (buf[current] != CTRL(escape_char)))
current++;
/* and write the sequence before esc char to the comm port */
if (current)
Expand Down