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eddys_snippets/Socket_CAN/can_io.c
Edward Emelianov 9192ee09a3 add serialsock
2022-01-19 17:31:04 +03:00

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/* CAN I/O library (to use as a process)
* usage:
* first: fork() + start_can_io(NULL) - start CAN Rx-buffering process
* then: fork() + Control_1(....) - start process that uses recv/send functions
* ...........................
* then: fork() + Control_N(....)
*
* note: use init_can_io() at the begining of every Control process
* BUT DON't USE it in main() before Control process start
* ^^^^^^^^^^^^^
*/
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
#include <string.h>
#include <time.h>
#include <sys/msg.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sys/time.h>
#include <fcntl.h>
#include <sys/file.h>
#include <sys/shm.h>
#include "can4linux.h"
#include "can_io.h"
char can_dev[40] = "/dev/can0";
int can_fd=-1;
char can_lck[40] = "/tmp/dev_can0.lock";
int can_lk=-1;
static int server_mode=0;
static int my_uid;
#define CAN_SHM_SIZE ((sizeof(int)*3)+CAN_CTLR_SIZE+(CAN_RX_SIZE*sizeof(canmsg_t)))
union ShMkey {
char name[5];
key_t code;
} can_shm_key;
int can_shm_id=-1;
char *can_shm_addr = NULL;
#define can_pid (*(((int *)can_shm_addr)+0)) /* PID of CAN I/O process */
#define can_open (*(((int *)can_shm_addr)+1)) /* file descr.of CAN-driver */
#define rx_buff_pntr (*(((int *)can_shm_addr)+2)) /* from 0 till CAN_RX_SIZE-1 */
void *can_ctrl_addr = NULL; /* shm area reserved for control process purpose*/
canmsg_t *rx_buff; /* rx ring buffer: CAN_RX_SIZE*sizeof(canmsg_t)*/
struct CMD_Queue { /* ÏÐÉÓÁÎÉÅ ÏÞÅÒÅÄÉ (ËÁÎÁÌÁ) ËÏÍÁÎÄ */
union {
char name[5]; /* ËÌÀÞ ÉÄÅÎÔÅÆÉËÁÃÉÉ ÏÞÅÒÅÄÉ */
key_t code;
} key;
int mode; /* ÒÅÖÉÍ ÄÏÓÔÕÐÁ (rwxrwxrwx) */
int side; /* ÔÉÐ ÐÏÄÓÏÅÄÉÎÅÎÉÑ: ëÌÉÅÎÔ/óÅÒ×ÅÒ (Sender/Receiver)*/
int id; /* ÄÅÓËÒÉÐÔÏÒ ÐÏÄÓÏÅÄÉÎÅÎÉÑ */
unsigned int acckey; /* ËÌÀÞ ÄÏÓÔÕÐÁ (ÄÌÑ ÐÅÒÅÄÁÞÉ ëÌÉÅÎÔ->óÅÒ×ÅÒ) */
};
/* ËÁÎÁÌ ËÏÍÁÎÄ ÉÓÐÏÌØÚÕÅÍ ÄÌÑ ÐÅÒÅÄÁÞÉ CAN-ÆÒÅÊÍÏ× */
static struct CMD_Queue canout = {{{'C','A','N',0,0}},0200,0,-1,0};
/* ÓÔÒÕËÔÕÒÁ ÓÏÏÂÝÅÎÉÑ */
struct my_msgbuf {
long mtype; /* type of message */
unsigned long acckey; /* ËÌÀÞ ÄÏÓÔÕÐÁ ËÌÉÅÎÔÁ */
unsigned long src_pid; /* ÎÏÍÅÒ ÐÒÏÃÅÓÓÁ ÉÓÔÏÞÎÉËÁ */
unsigned long src_ip; /* IP-ÁÄÒ. ÉÓÔÏÞÎÉËÁ, =0 - ÌÏËÁÌØÎÁÑ ËÏÍÁÎÄÁ */
char mtext[100]; /* message text */
};
static void can_abort(int sig);
void set_server_mode(int mode) {server_mode=mode;}
int can_server() {return(server_mode);}
int can_card() {return(can_fd>0);}
int can_gate() {return(0);}
double can_gate_time_offset() {return(0.0);}
unsigned long get_acckey() {return(0);}
static int shm_created=0;
/* to use _AFTER_ process forking */
void *init_can_io() { /* returns shared area addr. for client control process*/
int i;
int new_shm=0;
char *p, msg[100];
my_uid=geteuid();
if(can_shm_addr==NULL) {
if((p=strrchr(can_dev,'/'))!=NULL) {
memcpy(&can_lck[9], p+1, 4);
memcpy(can_shm_key.name, p+1, 4);
can_shm_key.name[4]='\0';
} else {
fprintf(stderr,"Wrong CAN device name: %s\n", can_dev);
return NULL;
}
can_shm_id = shmget(can_shm_key.code, CAN_SHM_SIZE, 0644);
if(can_shm_id<0 && errno==EACCES)
can_shm_id = shmget(can_shm_key.code, CAN_SHM_SIZE, 0444);
if(can_shm_id<0 && errno==ENOENT && server_mode) {
can_shm_id = shmget(can_shm_key.code, CAN_SHM_SIZE, IPC_CREAT|IPC_EXCL|0644);
new_shm = shm_created = 1;
}
if(can_shm_id<0) {
can_prtime(stderr);
if(new_shm)
sprintf(msg,"Can't create shm CAN buffer '%s'",can_shm_key.name);
else if(server_mode)
sprintf(msg,"CAN-I/O: Can't find shm segment for CAN buffer '%s'",can_shm_key.name);
else
sprintf(msg,"Can't find shm segment for CAN buffer '%s' (maybe no CAN-I/O process?)",can_shm_key.name);
perror(msg);
return NULL;
}
can_shm_addr = shmat(can_shm_id, NULL, 0);
if (can_shm_addr == (void*)-1 && errno==EACCES)
can_shm_addr = shmat(can_shm_id, NULL, SHM_RDONLY);
if (can_shm_addr == (void*)-1) {
sprintf(msg,"Can't attach shm CAN buffer '%s'",can_shm_key.name);
perror(msg);
shmctl(can_shm_id, IPC_RMID, NULL);
return NULL;
}
}
can_ctrl_addr = (canmsg_t *)(can_shm_addr+sizeof(int)*3);
rx_buff = (canmsg_t *)(can_ctrl_addr+CAN_CTLR_SIZE);
if(can_fd<0 && canout.id<0) {
if(server_mode) {
if(( can_fd = open(can_dev, O_RDWR )) < 0 ) {
sprintf(msg,"CAN-I/O: Error opening CAN device %s", can_dev);
can_prtime(stderr);
perror(msg);
shmctl(can_shm_id, IPC_RMID, NULL);
return NULL;
}
} else {
if((canout.id = msgget(canout.key.code, canout.mode)) < 0) {
sprintf(msg,"Error opening CAN output queue '%s'(maybe no CANqueue server process?) ",canout.key.name);
perror(msg);
}
}
}
if(can_lk>0) close(can_lk);
if(( can_lk = open(can_lck, O_RDWR|O_CREAT, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH )) < 0 ) {
sprintf(msg,"Error opening CAN device lock-file %s", can_lck);
perror(msg);
shmctl(can_shm_id, IPC_RMID, NULL);
close(can_fd);
return NULL;
}
fchmod(can_lk, S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP|S_IROTH|S_IWOTH);
if(new_shm) {
struct timeval tmv;
struct timezone tz;
gettimeofday(&tmv,&tz);
if(flock(can_lk, LOCK_EX)<0) perror("locking CAN");
can_pid = 0;
can_open = -1;
rx_buff_pntr = 0;
for(i=0; i<CAN_RX_SIZE; i++) {
rx_buff[i].id = 0;
rx_buff[i].timestamp = tmv;
}
if(flock(can_lk, LOCK_UN)<0) perror("unlocking CAN");
}
signal(SIGHUP, can_exit);
signal(SIGINT, can_exit);
signal(SIGQUIT,can_exit);
signal(SIGTERM,can_exit);
return(can_ctrl_addr);
}
/* CAN "Rx to buff" process */
void *start_can_io() {
set_server_mode(1);
init_can_io();
if(can_io_ok()) {
can_prtime(stderr);
fprintf(stderr,"CAN I/O process(%d) already running!\n",can_pid);
sleep(1);
can_prtime(stderr);
fprintf(stderr,"New CAN I/O process(%d) exiting...!\n",getpid());
exit(0);
}
if( can_fd < 0 ) {
can_prtime(stderr);
fprintf(stderr,"Error opening CAN device %s\n", can_dev);
shmctl(can_shm_id, IPC_RMID, NULL);
exit(0);
}
can_pid = getpid();
can_open = can_fd;
signal(SIGHUP, can_abort);
signal(SIGINT, can_abort);
signal(SIGQUIT,can_abort);
signal(SIGFPE, can_abort);
signal(SIGPIPE,can_abort);
signal(SIGSEGV,can_abort);
signal(SIGALRM, SIG_IGN);
signal(SIGTERM,can_abort);
if(shmctl(can_shm_id, SHM_LOCK, NULL) < 0)
perror("CAN I/O: can't prevents swapping of Rx-buffer area");
while(1) {
int n;
canmsg_t rx;
if(!can_io_shm_ok()) {can_delay(0.3); continue;}
n = can_wait(can_fd, 0.3);
if(n < 0) sleep(1);
if(n <= 0) continue;
// do {
static struct timeval tm = {0,0};
n = read(can_fd, &rx, sizeof(canmsg_t));
if(n < 0)
perror("CAN Rx error");
else if(n > 0) {
/* work around the timestamp bug in old driver version */
while((double)rx.timestamp.tv_sec+(double)rx.timestamp.tv_usec/1e6 < (double)tm.tv_sec+(double)tm.tv_usec/1e6) {
rx.timestamp.tv_usec += 10000;
if(rx.timestamp.tv_usec > 1000000) {
rx.timestamp.tv_sec++;
rx.timestamp.tv_usec -= 1000000;
}
}
if(flock(can_lk, LOCK_EX)<0) perror("locking CAN");
rx_buff[rx_buff_pntr] = rx;
rx_buff_pntr = (rx_buff_pntr + 1) % CAN_RX_SIZE;
if(flock(can_lk, LOCK_UN)<0) perror("unlocking CAN");
//fprintf(stderr,"%d read(id=%02x,len=%d)\n",rx_buff_pntr,rx.id,rx.length);fflush(stderr);
/*fprintf(stderr,"reading CAN: 1 frame\n");*/
} else {
fprintf(stderr,"reading CAN: nothing\n");fflush(stderr);
}
// } while(n>0);
}
}
/* put CAN-frame to recv-buffer */
void can_put_buff_frame(double rtime, int id, int length, unsigned char data[]) {
int i;
canmsg_t rx;
int sec = (int)rtime;
if(!server_mode) return;
if(length<0) length=0;
if(length>8) length=8;
rx.id=id;
rx.length=length;
for(i=0; i<length; i++) rx.data[i]=data[i];
rx.timestamp.tv_sec = sec;
rx.timestamp.tv_usec = (int)((rtime-sec)*1000000.);
if(flock(can_lk, LOCK_EX)<0) perror("locking CAN");
rx_buff[rx_buff_pntr] = rx;
rx_buff_pntr = (rx_buff_pntr + 1) % CAN_RX_SIZE;
if(flock(can_lk, LOCK_UN)<0) perror("unlocking CAN");
}
/* ÷ÓÅ ÎÏÒÍÁÌØÎÏ Ó SHM-ÂÕÆÅÒÏÍ CAN-I/O ÐÒÏÃÅÓÓÁ */
int can_io_shm_ok() {
return(can_pid>0 && can_open>0);
}
/* ÷ÓÅ ÎÏÒÍÁÌØÎÏ Ó CAN-I/O ÐÒÏÃÅÓÓÏÍ */
/* (ÎÏ ÎÁÄÏ ÂÙÔØ ÓÕÐÅÒ-ÀÚÅÒÏÍ!) */
int can_io_ok() {
return(can_io_shm_ok() && (my_uid!=0||kill(can_pid, 0)==0));
}
/* ÷ÏÚÍÏÖÎÁ ÒÁÂÏÔÁ c CAN ÄÌÑ ËÌÉÅÎÔÁ */
int can_ok() {
return(can_io_shm_ok());
}
/* wait for CAN-frame */
int can_wait(int fd, double tout)
{
int nfd,width;
struct timeval tv;
fd_set readfds;
if(fd==0 && tout>=0.01) {
double dt = can_dsleep(tout);
if(dt>0.) can_dsleep(dt);
return(0);
}
if(fd<0) fd=can_fd;
if(fd>0) {
FD_ZERO(&readfds);
FD_SET(fd, &readfds);
width = fd+1;
} else
width = 0;
tv.tv_sec = (int)tout;
tv.tv_usec = (int)((tout - tv.tv_sec)*1000000.+0.9);
slipping:
if(fd>0 && can_fd>0)
nfd = select(width, &readfds, (fd_set *)NULL, (fd_set *)NULL, &tv);
else
nfd = select(0, (fd_set *)NULL, (fd_set *)NULL, (fd_set *)NULL, &tv);
if(nfd < 0) {
if(errno == EINTR)
goto slipping;
perror("Error in can_wait(){ select() }");
return(-1);
} else if(nfd == 0) /* timeout! */
return(0);
if(fd>0 && FD_ISSET(fd, &readfds)) /* Rx frame! */
return(1);
return(0);
}
/* cleanup recv-buffer in client process */
void can_clean_recv(int *pbuf, double *rtime) {
struct timeval tmv;
struct timezone tz;
gettimeofday(&tmv,&tz);
*pbuf = rx_buff_pntr;
*rtime = tmv.tv_sec + (double)tmv.tv_usec/1000000.;
}
/* find next rx-frame in recv-buffer for client process */
int can_recv_frame(int *pbuf, double *rtime,
int *id, int *length, unsigned char data[]) {
return(can_get_buff_frame(pbuf, rtime, id, length, data));
}
int can_get_buff_frame(int *pbuf, double *rtime,
int *id, int *length, unsigned char data[]) {
while(*pbuf != rx_buff_pntr) {
canmsg_t *rx = &rx_buff[*pbuf];
struct timeval *tv = &rx->timestamp;
double t_rx;
if(flock(can_lk, LOCK_EX)<0) perror("locking CAN");
t_rx = tv->tv_sec + (double)tv->tv_usec/1000000.;
if(t_rx+1. >= *rtime) {
int i;
*id = rx->id;
*length = rx->length;
for(i = 0; i < *length; i++)
data[i] = rx->data[i];
*rtime = t_rx;
*pbuf = (*pbuf + 1) % CAN_RX_SIZE;
if(flock(can_lk, LOCK_UN)<0) perror("unlocking CAN");
return(1);
}
*pbuf = (*pbuf + 1) % CAN_RX_SIZE;
if(flock(can_lk, LOCK_UN)<0) perror("unlocking CAN");
}
return(0);
}
/* send tx-frame from client process */
/* to CAN-driver or to output queue */
int can_send_frame(int id, int length, unsigned char data[]) {
int i, ret=1;
if(can_fd<0 && canout.id<0)
return(0);
if(length>8) length=8;
if(length<0) length=0;
if(can_fd>=0) {
canmsg_t tx;
tx.id=id;
tx.cob=0;
tx.flags=0;
tx.length=length;
for(i=0;i<length;i++) tx.data[i]=data[i];
if(flock(can_lk, LOCK_EX)<0) perror("locking CAN");
ret = write(can_fd, &tx, sizeof(canmsg_t));
if(flock(can_lk, LOCK_UN)<0) perror("unlocking CAN");
if(server_mode)
/* copy tx CAN-frame back to recv-buffer */
can_put_buff_frame(can_dtime(), id, length, data);
} else if(canout.id>=0) {
struct my_msgbuf mbuf;
mbuf.src_pid = getpid();
mbuf.src_ip = 0;
mbuf.acckey = canout.acckey;
mbuf.mtype = id;
for(i=0;i<length;i++) mbuf.mtext[i]=data[i];
msgsnd( canout.id, (struct msgbuf *)&mbuf, length+12, IPC_NOWAIT);
}
return(ret);
}
static void can_abort(int sig) {
char ss[10];
struct shmid_ds buf;
if(sig) signal(sig,SIG_IGN);
if(!server_mode) can_exit(sig);
switch (sig) {
case 0 : strcpy(ss," "); break;
case SIGHUP : strcpy(ss,"SIGHUP -"); break;
case SIGINT : strcpy(ss,"SIGINT -"); break;
case SIGQUIT: strcpy(ss,"SIGQUIT -"); break;
case SIGFPE : strcpy(ss,"SIGFPE -"); break;
case SIGPIPE: strcpy(ss,"SIGPIPE -"); break;
case SIGSEGV: strcpy(ss,"SIGSEGV -"); break;
case SIGTERM: strcpy(ss,"SIGTERM -"); break;
default: sprintf(ss,"SIG_%d -",sig); break;
}
switch (sig) {
default:
case SIGHUP :
case SIGINT :
can_prtime(stderr);
fprintf(stderr,"CAN I/O: %s Ignore .....\n",ss);
fflush(stderr);
signal(sig, can_abort);
return;
case SIGPIPE:
case SIGQUIT:
case SIGFPE :
case SIGSEGV:
case SIGTERM:
signal(SIGALRM, can_abort);
alarm(2);
can_prtime(stderr);
fprintf(stderr,"CAN I/O: %s process should stop after 2sec delay...\n",ss);
fflush(stderr);
close(can_fd);
can_fd = can_open = -1;
return;
case SIGALRM:
can_prtime(stderr);
fprintf(stderr,"CAN I/O: process stop!\n");
fflush(stderr);
close(can_lk);
can_lk = -1;
can_pid = 0;
shmdt(can_shm_addr);
shmctl(can_shm_id, IPC_STAT, &buf);
if(buf.shm_nattch==0) {
shmctl(can_shm_id, SHM_UNLOCK, NULL);
shmctl(can_shm_id, IPC_RMID, NULL);
}
exit(sig);
}
}
void can_exit(int sig) {
char ss[12];
struct shmid_ds buf;
if(sig) signal(sig,SIG_IGN);
if(server_mode) can_abort(sig);
switch (sig) {
case 0 : strcpy(ss,"Exiting - "); break;
case SIGHUP : strcpy(ss,"SIGHUP -"); break;
case SIGINT : strcpy(ss,"SIGINT -"); break;
case SIGQUIT: strcpy(ss,"SIGQUIT -"); break;
case SIGFPE : strcpy(ss,"SIGFPE -"); break;
case SIGPIPE: strcpy(ss,"SIGPIPE -"); break;
case SIGSEGV: strcpy(ss,"SIGSEGV -"); break;
case SIGTERM: strcpy(ss,"SIGTERM -"); break;
default: sprintf(ss,"SIG_%d -",sig); break;
}
switch (sig) {
default:
case SIGHUP :
can_prtime(stderr);
fprintf(stderr,"%s Ignore .....\n",ss);
fflush(stderr);
signal(sig, can_exit);
return;
case 0:
case SIGINT :
case SIGPIPE:
case SIGQUIT:
case SIGFPE :
case SIGSEGV:
case SIGTERM:
if(can_fd>=0) close(can_fd);
can_prtime(stderr);
fprintf(stderr,"%s process stop!\n",ss);
fflush(stderr);
close(can_lk);
shmdt(can_shm_addr);
shmctl(can_shm_id, IPC_STAT, &buf);
if(buf.shm_nattch==0)
shmctl(can_shm_id, IPC_RMID, NULL);
exit(sig);
}
}
char *time2asc(double t)
{
static char stmp[10][20];
static int itmp=0;
char *lin = stmp[itmp];
int h, min;
double sec;
h = (int)(t/3600.);
min = (int)((t - (double)h*3600.)/60.);
sec = t - (double)h*3600. - (double)min*60.;
h %= 24;
sprintf(lin, "%02d:%02d:%09.6f", h,min,sec);
itmp = (itmp+1)%10;
return lin;
}
double can_dsleep(double dt) {
struct timespec ts,tsr;
ts.tv_sec = (time_t)dt;
ts.tv_nsec = (long)((dt-ts.tv_sec)*1e9);
nanosleep(&ts,&tsr);
return((double)ts.tv_sec + (double)ts.tv_nsec/1e9);
}
double can_dtime() {
struct timeval ct;
struct timezone tz;
gettimeofday(&ct, &tz);
return ((double)ct.tv_sec + (double)ct.tv_usec/1e6);
}
char *can_atime() {return(time2asc(can_dtime()));}
void can_prtime(FILE *fd) {
static double otime=0.0;
double ntime=can_dtime();
time_t itime = (int)ntime;
if(otime==0.0) tzset();
ntime -= (double)timezone;
if((((int)ntime)%(24*3600) < ((int)otime)%(24*3600)) || otime==0.0)
fprintf(fd,"========================\n%s",ctime(&itime));
fprintf(fd,"%s ",time2asc(ntime));
otime=ntime;
}
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