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a2f1d6959d36a87c5cb7d50b180284be47c4c4b0
bacnet_stack/ports/linux/rs485.c
T
Kari Argillander a2f1d6959d Make most of functions const correct (#714) 
* Make most of the functions const correct

Used clang-tidy and sonarlint to help find places where const could
pretty easily applied. Also lot of hand work.

This commit does not yet touch handlers and typedefs of those.

* Fix Arduino uno handler_who_is() has extra parenthesis

For some reason there is extra parenthesis. Remove it this is more
likely buildable.

* Bugfix/bacapp: Fix uninitilized array_index

We have changed bacapp_snprintf_value() to be const correct. After that
we got

```
/home/runner/work/bacnet-stack/bacnet-stack/src/bacnet/bacapp.c:3183:27: warning: 4th function call argument is an uninitialized value [core.CallAndMessage]
                ret_val = bacapp_snprintf_weeklyschedule(
                          ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
1 warning generated.
```

So analyzer could now spot that we do not actually initilize array_index
at all. Fix this by setting array_index to zero. Note that I actually do
not know if zeroing is right thing to do here. I choose zero as if this
has worked before it is most likely that it will work with zero value.

* cmake: Add and ignore Wwrite-strings compiler option

Wwrite-strings helps find places where const correctness is broken.

Example it will warn about these

```C

void func1(char* str);

func("test") /* "test" is const so we should not pass it to func1().

char* func2()
{
  return "test"; /* func2() should return const char*.
}
```

We still need to ignore it as not all are fixed but let's add it already
so we remember that it should be opened at some point.

---------

Co-authored-by: Kari Argillander <kari.argillander@fidelix.com>
2024-08-29 14:08:02 -05:00

712 lines
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/**************************************************************************
*
* Copyright (C) 2007 Steve Karg <skarg@users.sourceforge.net>
* Updated by Nikola Jelic 2011 <nikola.jelic@euroicc.com>
*
* SPDX-License-Identifier: GPL-2.0-or-later WITH GCC-exception-2.0
*
*********************************************************************/
/** @file linux/rs485.c Provides Linux-specific functions for RS-485 serial. */
/* The module handles sending data out the RS-485 port */
/* and handles receiving data from the RS-485 port. */
/* Customize this file for your specific hardware */
#include <errno.h>
#include <stddef.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
/* Linux includes */
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <termios.h>
#include <unistd.h>
#include <sched.h>
#include <linux/serial.h> /* for struct serial_struct */
#include <math.h> /* for calculation of custom divisor */
#include <sys/ioctl.h>
/* for scandir */
#include <dirent.h>
/* for basename */
#include <libgen.h>
/* Local includes */
#include "bacnet/datalink/mstp.h"
#include "rs485.h"
#include "bacnet/basic/sys/fifo.h"
#include <sys/select.h>
#include <sys/time.h>
#include "dlmstp_linux.h"
/* Posix serial programming reference:
http://www.easysw.com/~mike/serial/serial.html */
/* Use ionice wrapper to improve serial performance:
$ sudo ionice -c 1 -n 0 ./bin/bacserv 12345
*/
/* handle returned from open() */
static int RS485_Handle = -1;
/* baudrate settings are defined in <asm/termbits.h>, which is
included by <termios.h> */
static unsigned int RS485_Baud = B38400;
/* serial port name, /dev/ttyS0,
/dev/ttyUSB0 for USB->RS485 from B&B Electronics USOPTL4 */
static char *RS485_Port_Name = "/dev/ttyUSB0";
/* some terminal I/O have RS-485 specific functionality */
#ifndef RS485MOD
#define RS485MOD 0
#endif
/* serial I/O settings */
static struct termios RS485_oldtio;
/* for setting custom divisor */
static struct serial_struct RS485_oldserial;
/* indicator of special baud rate */
static bool RS485_SpecBaud = false;
/* Ring buffer for incoming bytes, in order to speed up the receiving. */
static FIFO_BUFFER Rx_FIFO;
/* buffer size needs to be a power of 2 */
static uint8_t Rx_Buffer[4096];
#define _POSIX_SOURCE 1 /* POSIX compliant source */
/*********************************************************************
* DESCRIPTION: Configures the interface name
* RETURN: none
* ALGORITHM: none
* NOTES: none
*********************************************************************/
void RS485_Set_Interface(char *ifname)
{
/* note: expects a constant char, or char from the heap */
if (ifname) {
RS485_Port_Name = ifname;
}
}
/*********************************************************************
* DESCRIPTION: Returns the interface name
* RETURN: none
* ALGORITHM: none
* NOTES: none
*********************************************************************/
const char *RS485_Interface(void)
{
return RS485_Port_Name;
}
/****************************************************************************
* DESCRIPTION: Returns the baud rate that we are currently running at
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
uint32_t RS485_Get_Baud_Rate(void)
{
uint32_t baud = 0;
switch (RS485_Baud) {
case B0:
baud = 0;
break;
case B50:
baud = 50;
break;
case B75:
baud = 75;
break;
case B110:
baud = 110;
break;
case B134:
baud = 134;
break;
case B150:
baud = 150;
break;
case B200:
baud = 200;
break;
case B300:
baud = 300;
break;
case B600:
baud = 600;
break;
case B1200:
baud = 1200;
break;
case B1800:
baud = 1800;
break;
case B2400:
baud = 2400;
break;
case B4800:
baud = 4800;
break;
case B9600:
baud = 9600;
break;
case B19200:
baud = 19200;
break;
case B38400:
if (!RS485_SpecBaud) {
/* Linux asks for custom divisor
only when baud is set on 38400 */
baud = 38400;
} else {
baud = 76800;
}
break;
case B57600:
baud = 57600;
break;
case B115200:
baud = 115200;
break;
case B230400:
baud = 230400;
break;
default:
baud = 9600;
}
return baud;
}
/****************************************************************************
* DESCRIPTION: Returns the baud rate that we are currently running at
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
uint32_t RS485_Get_Port_Baud_Rate(struct mstp_port_struct_t *mstp_port)
{
uint32_t baud = 0;
SHARED_MSTP_DATA *poSharedData = (SHARED_MSTP_DATA *)mstp_port->UserData;
if (!poSharedData) {
return 0;
}
switch (poSharedData->RS485_Baud) {
case B0:
baud = 0;
break;
case B50:
baud = 50;
break;
case B75:
baud = 75;
break;
case B110:
baud = 110;
break;
case B134:
baud = 134;
break;
case B150:
baud = 150;
break;
case B200:
baud = 200;
break;
case B300:
baud = 300;
break;
case B600:
baud = 600;
break;
case B1200:
baud = 1200;
break;
case B1800:
baud = 1800;
break;
case B2400:
baud = 2400;
break;
case B4800:
baud = 4800;
break;
case B9600:
baud = 9600;
break;
case B19200:
baud = 19200;
break;
case B38400:
baud = 38400;
break;
case B57600:
baud = 57600;
break;
case B115200:
baud = 115200;
break;
case B230400:
baud = 230400;
break;
default:
baud = 9600;
break;
}
return baud;
}
/****************************************************************************
* DESCRIPTION: Sets the baud rate for the chip USART
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
bool RS485_Set_Baud_Rate(uint32_t baud)
{
bool valid = true;
RS485_SpecBaud = false;
switch (baud) {
case 0:
RS485_Baud = B0;
break;
case 50:
RS485_Baud = B50;
break;
case 75:
RS485_Baud = B75;
break;
case 110:
RS485_Baud = B110;
break;
case 134:
RS485_Baud = B134;
break;
case 150:
RS485_Baud = B150;
break;
case 200:
RS485_Baud = B200;
break;
case 300:
RS485_Baud = B300;
break;
case 600:
RS485_Baud = B600;
break;
case 1200:
RS485_Baud = B1200;
break;
case 1800:
RS485_Baud = B1800;
break;
case 2400:
RS485_Baud = B2400;
break;
case 4800:
RS485_Baud = B4800;
break;
case 9600:
RS485_Baud = B9600;
break;
case 19200:
RS485_Baud = B19200;
break;
case 38400:
RS485_Baud = B38400;
break;
case 57600:
RS485_Baud = B57600;
break;
case 76800:
RS485_Baud = B38400;
RS485_SpecBaud = true;
break;
case 115200:
RS485_Baud = B115200;
break;
case 230400:
RS485_Baud = B230400;
break;
default:
valid = false;
break;
}
if (valid) {
/* FIXME: store the baud rate */
}
return valid;
}
/****************************************************************************
* DESCRIPTION: Transmit a frame on the wire
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
void RS485_Send_Frame(
struct mstp_port_struct_t *mstp_port, /* port specific data */
const uint8_t *buffer, /* frame to send (up to 501 bytes of data) */
uint16_t nbytes)
{ /* number of bytes of data (up to 501) */
uint32_t turnaround_time = Tturnaround * 1000;
uint32_t baud;
ssize_t written = 0;
int greska;
const SHARED_MSTP_DATA *poSharedData = NULL;
if (mstp_port) {
poSharedData = (SHARED_MSTP_DATA *)mstp_port->UserData;
}
if (!poSharedData) {
baud = RS485_Get_Baud_Rate();
/* sleeping for turnaround time is necessary to give other devices
time to change from sending to receiving state. */
usleep(turnaround_time / baud);
/*
On success, the number of bytes written are returned (zero
indicates nothing was written). On error, -1 is returned, and
errno is set appropriately. If count is zero and the file
descriptor refers to a regular file, 0 will be returned without
causing any other effect. For a special file, the results are not
portable.
*/
written = write(RS485_Handle, buffer, nbytes);
greska = errno;
if (written <= 0) {
printf("write error: %s\n", strerror(greska));
} else {
/* wait until all output has been transmitted. */
tcdrain(RS485_Handle);
}
/* tcdrain(RS485_Handle); */
/* per MSTP spec, sort of */
if (mstp_port) {
mstp_port->SilenceTimerReset((void *)mstp_port);
}
} else {
baud = RS485_Get_Port_Baud_Rate(mstp_port);
/* sleeping for turnaround time is necessary to give other devices
time to change from sending to receiving state. */
usleep(turnaround_time / baud);
/*
On success, the number of bytes written are returned (zero
indicates nothing was written). On error, -1 is returned, and
errno is set appropriately. If count is zero and the file
descriptor refers to a regular file, 0 will be returned without
causing any other effect. For a special file, the results are not
portable.
*/
written = write(poSharedData->RS485_Handle, buffer, nbytes);
greska = errno;
if (written <= 0) {
printf("write error: %s\n", strerror(greska));
} else {
/* wait until all output has been transmitted. */
tcdrain(poSharedData->RS485_Handle);
}
/* tcdrain(RS485_Handle); */
/* per MSTP spec, sort of */
if (mstp_port) {
mstp_port->SilenceTimerReset((void *)mstp_port);
}
}
return;
}
/****************************************************************************
* DESCRIPTION: Get a byte of receive data
* RETURN: none
* ALGORITHM: none
* NOTES: none
*****************************************************************************/
void RS485_Check_UART_Data(struct mstp_port_struct_t *mstp_port)
{
fd_set input;
struct timeval waiter;
uint8_t buf[2048];
int n;
SHARED_MSTP_DATA *poSharedData = (SHARED_MSTP_DATA *)mstp_port->UserData;
if (!poSharedData) {
if (mstp_port->ReceiveError == true) {
/* do nothing but wait for state machine to clear the error */
/* burning time, so wait a longer time */
waiter.tv_sec = 0;
waiter.tv_usec = 5000;
} else if (mstp_port->DataAvailable == false) {
/* wait for state machine to read from the DataRegister */
if (FIFO_Count(&Rx_FIFO) > 0) {
/* data is available */
mstp_port->DataRegister = FIFO_Get(&Rx_FIFO);
mstp_port->DataAvailable = true;
/* FIFO is giving data - just poll */
waiter.tv_sec = 0;
waiter.tv_usec = 0;
} else {
/* FIFO is empty - wait a longer time */
waiter.tv_sec = 0;
waiter.tv_usec = 5000;
}
}
/* grab bytes and stuff them into the FIFO every time */
FD_ZERO(&input);
FD_SET(RS485_Handle, &input);
n = select(RS485_Handle + 1, &input, NULL, NULL, &waiter);
if (n < 0) {
return;
}
if (FD_ISSET(RS485_Handle, &input)) {
n = read(RS485_Handle, buf, sizeof(buf));
FIFO_Add(&Rx_FIFO, &buf[0], n);
}
} else {
if (mstp_port->ReceiveError == true) {
/* do nothing but wait for state machine to clear the error */
/* burning time, so wait a longer time */
waiter.tv_sec = 0;
waiter.tv_usec = 5000;
} else if (mstp_port->DataAvailable == false) {
/* wait for state machine to read from the DataRegister */
if (FIFO_Count(&poSharedData->Rx_FIFO) > 0) {
/* data is available */
mstp_port->DataRegister = FIFO_Get(&poSharedData->Rx_FIFO);
mstp_port->DataAvailable = true;
/* FIFO is giving data - just poll */
waiter.tv_sec = 0;
waiter.tv_usec = 0;
} else {
/* FIFO is empty - wait a longer time */
waiter.tv_sec = 0;
waiter.tv_usec = 5000;
}
}
/* grab bytes and stuff them into the FIFO every time */
FD_ZERO(&input);
FD_SET(poSharedData->RS485_Handle, &input);
n = select(poSharedData->RS485_Handle + 1, &input, NULL, NULL, &waiter);
if (n < 0) {
return;
}
if (FD_ISSET(poSharedData->RS485_Handle, &input)) {
n = read(poSharedData->RS485_Handle, buf, sizeof(buf));
FIFO_Add(&poSharedData->Rx_FIFO, &buf[0], n);
}
}
}
void RS485_Cleanup(void)
{
/* restore the old port settings */
tcsetattr(RS485_Handle, TCSANOW, &RS485_oldtio);
ioctl(RS485_Handle, TIOCSSERIAL, &RS485_oldserial);
close(RS485_Handle);
}
void RS485_Initialize(void)
{
struct termios newtio;
struct serial_struct newserial;
float baud_error = 0.0;
#if PRINT_ENABLED
fprintf(stdout, "RS485 Interface: %s\n", RS485_Port_Name);
#endif
/*
Open device for reading and writing.
Blocking mode - more CPU effecient
*/
RS485_Handle = open(RS485_Port_Name, O_RDWR | O_NOCTTY /*| O_NDELAY */);
if (RS485_Handle < 0) {
perror(RS485_Port_Name);
exit(-1);
}
#if 0
/* non blocking for the read */
fcntl(RS485_Handle, F_SETFL, FNDELAY);
#else
/* efficient blocking for the read */
fcntl(RS485_Handle, F_SETFL, 0);
#endif
/* save current serial port settings */
tcgetattr(RS485_Handle, &RS485_oldtio);
/* we read the old serial setup */
ioctl(RS485_Handle, TIOCGSERIAL, &RS485_oldserial);
/* we need a copy of existing settings */
memcpy(&newserial, &RS485_oldserial, sizeof(struct serial_struct));
/* clear struct for new port settings */
bzero(&newtio, sizeof(newtio));
/*
BAUDRATE: Set bps rate. You could also use cfsetispeed and cfsetospeed.
CRTSCTS : output hardware flow control (only used if the cable has
all necessary lines. See sect. 7 of Serial-HOWTO)
CS8 : 8n1 (8bit,no parity,1 stopbit)
CLOCAL : local connection, no modem contol
CREAD : enable receiving characters
*/
newtio.c_cflag = RS485_Baud | CS8 | CLOCAL | CREAD | RS485MOD;
/* Raw input */
newtio.c_iflag = 0;
/* Raw output */
newtio.c_oflag = 0;
/* no processing */
newtio.c_lflag = 0;
/* activate the settings for the port after flushing I/O */
tcsetattr(RS485_Handle, TCSAFLUSH, &newtio);
if (RS485_SpecBaud) {
/* 76800, custom divisor must be set */
newserial.flags |= ASYNC_SPD_CUST;
newserial.custom_divisor = round(((float)newserial.baud_base) / 76800);
/* we must check that we calculated some sane value;
small baud bases yield bad custom divisor values */
baud_error = fabs(1 -
((float)newserial.baud_base) / ((float)newserial.custom_divisor) /
76800);
if ((newserial.custom_divisor == 0) || (baud_error > 0.02)) {
/* bad divisor */
fprintf(stderr, "RS485 bad custom divisor %d, base baud %d\n",
newserial.custom_divisor, newserial.baud_base);
exit(EXIT_FAILURE);
}
/* if all goes well, set new divisor */
ioctl(RS485_Handle, TIOCSSERIAL, &newserial);
}
#if PRINT_ENABLED
fprintf(stdout, "RS485 Baud Rate %u\n", RS485_Get_Baud_Rate());
fflush(stdout);
#endif
/* destructor */
atexit(RS485_Cleanup);
/* flush any data waiting */
usleep(200000);
tcflush(RS485_Handle, TCIOFLUSH);
/* ringbuffer */
FIFO_Init(&Rx_FIFO, Rx_Buffer, sizeof(Rx_Buffer));
}
/* Print in a format for Wireshark ExtCap */
void RS485_Print_Ports(void)
{
int n;
struct dirent **namelist;
const char *sysdir = "/sys/class/tty/";
struct stat st;
char buffer[1024];
char device_dir[1024];
char *driver_name = NULL;
int fd = 0;
bool valid_port = false;
struct serial_struct serinfo;
/* Scan through /sys/class/tty -
it contains all tty-devices in the system */
n = scandir(sysdir, &namelist, NULL, NULL);
if (n < 0) {
perror("RS485: scandir");
} else {
while (n--) {
if (strcmp(namelist[n]->d_name, "..") &&
strcmp(namelist[n]->d_name, ".")) {
snprintf(device_dir, sizeof(device_dir), "%s%s/device", sysdir,
namelist[n]->d_name);
/* Stat the devicedir and handle it if it is a symlink */
if (lstat(device_dir, &st) == 0 && S_ISLNK(st.st_mode)) {
memset(buffer, 0, sizeof(buffer));
snprintf(device_dir, sizeof(device_dir),
"%s%s/device/driver", sysdir, namelist[n]->d_name);
if (readlink(device_dir, buffer, sizeof(buffer)) > 0) {
valid_port = false;
driver_name = basename(buffer);
if (strcmp(driver_name, "serial8250") == 0) {
/* serial8250-devices must be probed */
snprintf(device_dir, sizeof(device_dir), "/dev/%s",
namelist[n]->d_name);
fd = open(
device_dir, O_RDWR | O_NONBLOCK | O_NOCTTY);
if (fd >= 0) {
/* Get serial_info */
if (ioctl(fd, TIOCGSERIAL, &serinfo) == 0) {
/* If device type is not PORT_UNKNOWN */
/* we accept the port */
if (serinfo.type != PORT_UNKNOWN) {
valid_port = true;
}
}
close(fd);
}
} else {
valid_port = true;
}
if (valid_port) {
/* print full absolute file path */
printf("interface {value=/dev/%s}"
"{display=MS/TP Capture on /dev/%s}\n",
namelist[n]->d_name, namelist[n]->d_name);
}
}
}
}
free(namelist[n]);
}
free(namelist);
}
}
#ifdef TEST_RS485
#include <string.h>
int main(int argc, char *argv[])
{
struct mstp_port_struct_t mstp_port = { 0 };
uint8_t token_buf[8] = { 0x55, 0xFF, 0x00, 0x7E, 0x07, 0x00, 0x00, 0xFD };
uint8_t pfm_buf[8] = { 0x55, 0xFF, 0x01, 0x67, 0x07, 0x00, 0x00, 0x3E };
long baud = 38400;
bool write_token = false;
bool write_pfm = false;
/* argv has the "/dev/ttyS0" or some other device */
if (argc > 1) {
RS485_Set_Interface(argv[1]);
}
if (argc > 2) {
baud = strtol(argv[2], NULL, 0);
}
if (argc > 3) {
if (strcmp("token", argv[3]) == 0) {
write_token = true;
}
if (strcmp("pfm", argv[3]) == 0) {
write_pfm = true;
}
}
RS485_Set_Baud_Rate(baud);
RS485_Initialize();
for (;;) {
if (write_token) {
RS485_Send_Frame(NULL, token_buf, sizeof(token_buf));
usleep(25000);
} else if (write_pfm) {
RS485_Send_Frame(NULL, pfm_buf, sizeof(pfm_buf));
usleep(100000);
} else {
RS485_Check_UART_Data(&mstp_port);
if (mstp_port.DataAvailable) {
fprintf(stderr, "%02X ", mstp_port.DataRegister);
mstp_port.DataAvailable = false;
}
}
}
return 0;
}
#endif
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