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on Linux and Mac, allow to lock the device with flock(), if it's already locked elsewhere then close it

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This commit is contained in:
Antoine Rousseau 2024-10-09 12:07:37 +02:00
parent e85a17be38
commit f01764a67e
1 changed files with 75 additions and 0 deletions
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75
comport.c
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@ -43,6 +43,7 @@ JZ 20210321 allow the user to specify a device pattern as creation argument
#include <fcntl.h>
#include <sys/ioctl.h> /* for ioctl DTR */
#include <termios.h> /* for TERMIO ioctl calls */
#include <sys/file.h> /* for flock() */
#include <unistd.h>
#include <glob.h>
#define HANDLE int
@ -74,6 +75,8 @@ typedef struct comport
int comhandle; /* holds the comport handle */
struct termios oldcom_termio; /* save the old com config */
struct termios com_termio; /* for the new com config */
t_bool x_lock; /* the file descriptor has to be locked when opened */
t_bool x_locked; /* the file descriptor has been locked */
#endif
/* device specifications */
@ -933,6 +936,58 @@ static int set_break(t_comport *x, int on)
return ((status < 0)? status: (on != 0));
}
static t_bool lock_fd(t_comport *x, int fd, int lock)
{
int operation = (lock ? LOCK_EX : LOCK_UN) | LOCK_NB;
int ret;
if((lock == x->x_locked) || (fd == INVALID_HANDLE_VALUE)) return 1;
ret = flock(fd, operation);
if(ret == 0) {
x->x_locked = lock;
}
return (ret == 0);
}
static void check_lock(t_comport *x)
{
if(x->x_lock) {
if(!lock_fd(x, x->comhandle, 1)) {
comport_verbose("[comport] file descriptor of %s is already locked, closing!\n",
x->serial_device->s_name);
comport_close(x);
}
}
}
#if 0
t_bool check_file_availability(const char *device_name)
{
FILE *fp;
int status;
char buffer[256];
snprintf(buffer, sizeof(buffer), "fuser %s", device_name);
fp = popen(buffer, "r");
if (fp == NULL) return 0;
/*while (fgets(buffer, sizeof(buffer), fp) != NULL)
{
//printf("%s", buffer);
}*/
status = pclose(fp);
if (status == -1) {
/* Error reported by pclose() */
} else {
/* Use macros described under wait() to inspect `status' in order
to determine success/failure of command executed by popen() */
}
return 1;
}
#endif
static int open_serial(unsigned int com_num, t_comport *x)
{
int fd;
@ -989,6 +1044,8 @@ static int open_serial(unsigned int com_num, t_comport *x)
}
globfree( &(glob_buffer) );
//check_file_availability(x->serial_device->s_name);
if((fd = open(x->serial_device->s_name, OPENPARAMS)) == INVALID_HANDLE_VALUE)
{
pd_error(x, "[comport] ** ERROR ** could not open device %s:\n failure(%d): %s\n",
@ -1073,6 +1130,7 @@ static int close_serial(t_comport *x)
if(fd != INVALID_HANDLE_VALUE)
{
lock_fd(x, fd, 0);
tcsetattr(fd, TCSANOW, tios);
close(fd);
comport_verbose("[comport] closed port %i (%s)", x->comport, x->serial_device->s_name);
@ -1480,6 +1538,9 @@ static void *comport_new(t_symbol *s, int argc, t_atom *argv)
x->x_verbose = 0;
x->x_inprocess = 0;
#ifndef _WIN32
x->x_lock = x->x_locked = 0;
#endif
return x;
}
@ -1654,6 +1715,13 @@ static void comport_close(t_comport *x)
if (x->x_status_outlet != NULL) outlet_float(x->x_status_outlet, (float)x->comport);
}
static void comport_lock(t_comport *x, t_floatarg f)
{
#ifndef _WIN32
x->x_lock = (f != 0);
#endif
}
static void comport_open(t_comport *x, t_floatarg f)
{
if(x->comhandle != INVALID_HANDLE_VALUE)
@ -1662,6 +1730,9 @@ static void comport_open(t_comport *x, t_floatarg f)
x->comhandle = open_serial(f,x);
clock_delay(x->x_clock, x->x_deltime);
#ifndef _WIN32
check_lock(x);
#endif
}
/*
@ -1677,6 +1748,9 @@ static void comport_devicename(t_comport *x, t_symbol *s)
x->comhandle = open_serial(USE_DEVICENAME,x);
clock_delay(x->x_clock, x->x_deltime);
#ifndef _WIN32
check_lock(x);
#endif
}
static void comport_print(t_comport *x, t_symbol *s, int argc, t_atom *argv)
@ -1986,6 +2060,7 @@ void comport_setup(void)
class_addmethod(comport_class, (t_method)comport_parity, gensym("parity"), A_FLOAT, 0);
class_addmethod(comport_class, (t_method)comport_xonxoff, gensym("xonxoff"), A_FLOAT, 0);
class_addmethod(comport_class, (t_method)comport_hupcl, gensym("hupcl"), A_FLOAT, 0);
class_addmethod(comport_class, (t_method)comport_lock, gensym("lock"), A_FLOAT, 0);
class_addmethod(comport_class, (t_method)comport_close, gensym("close"), 0);
class_addmethod(comport_class, (t_method)comport_open, gensym("open"), A_FLOAT, 0);
class_addmethod(comport_class, (t_method)comport_devicename, gensym("devicename"), A_SYMBOL, 0);