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slcand: add slcan_attach and UART settings

PATCH Stefan Wahren 2 participants 2 messages Sep 2, 2013 – Sep 10, 2013 1 message not in the archive CAN network drivers

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Stefan Wahren

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#1 lore raw
In reply to a message not in the archive

Hello Yegor,

as requested on GitHub here are my comments:

Quoted 48 lines

slcand takes settings known from slcan_attach to configure CAN interface, like open/close channel, set bitrate etc. In addition -S option sets UART's baudrate. This way slcand combines three utilities in one: old slcand, slcan_attach and stty.

Example: slcand -o -s8 -S 3000000 ttyUSB0

Signed-off-by Yegor Yefremov <[email protected]>
---
 slcand.c |  295 
+++++++++++++++++++++++++++++++++++++++++++++++++++++--------
 1 files changed, 256 insertions(+), 39 deletions(-)
slcand.c +5 -6
index 807ffaa..92ffa20 100644
@@ -40,16 +40,16 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
 #include <fcntl.h>
 #include <syslog.h>
 #include <errno.h>
 #include <pwd.h>
 #include <signal.h>
-#include <sys/socket.h>
 #include <sys/ioctl.h>
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <net/if.h>
+#include <termios.h>
 
 /* default slcan line discipline since Kernel 2.6.25 */
 #define LDISC_N_SLCAN 17

@@ -69,46 +69,126 @@
 #define EXIT_SUCCESS 0
 #define EXIT_FAILURE 1
 
+
+
 void print_usage(char *prg)
 {
-    fprintf(stderr, "\nUsage: %s tty [name]\n\n", prg);
-    fprintf(stderr, "Example:\n");
-    fprintf(stderr, "%s ttyUSB1\n", prg);

slcand.c line 84

Quoted 10 lines
slcand.c +6 -1
-    fprintf(stderr, "%s ttyS0 can0\n", prg);
+    fprintf(stderr, "\nUsage: %s [options] <tty> [canif-name]\n\n", 
 prg);
+    fprintf(stderr, "Options: -o         (send open command 'O\\r')\n");
+    fprintf(stderr, "         -c         (send close command 
 'C\\r')\n");
+    fprintf(stderr, "         -f         (read status flags with 
 'F\\r' to reset error states)\n");
+    fprintf(stderr, "         -s <speed> (set CAN speed 0..8)\n");
+    fprintf(stderr, "         -S <speed> (set UART speed)\n");

It would be nice for the user to know the range of the UART speed and it is in baud.

Quoted 19 lines
slcand.c +13 -0
+ fprintf(stderr, "         -b <btr>   (set bit time register value)\n");
+    fprintf(stderr, "         -F         (stay in foreground; no 
 daemonize)\n");
+    fprintf(stderr, "         -h         (show this help page)\n");
+    fprintf(stderr, "\nExamples:\n");
+    fprintf(stderr, "slcand -o -c -f -s6 ttyslcan0\n");
+    fprintf(stderr, "slcand -o -c -f -s6 ttyslcan0 can0\n");
     fprintf(stderr, "\n");
     exit(EXIT_FAILURE);
 }
 
+
+static int slcand_running = 0;
+static int exit_code = 0;
+static char ttypath[TTYPATH_LENGTH];
+static char pidfile[PIDFILE_LENGTH];
+
+
 static void child_handler (int signum)

slcand.c line 109

Quoted 10 lines
slcand.c +2 -4
 {
     switch (signum)
     {
-    case SIGALRM:
-        exit (EXIT_FAILURE);
-        break;
     case SIGUSR1:
-        exit (EXIT_SUCCESS);
+        /* exit parent */
+        exit(EXIT_SUCCESS);

Please try to keep code convention.

Quoted 11 lines
slcand.c +7 -1
 break;
+    case SIGALRM:
     case SIGCHLD:
-        exit (EXIT_FAILURE);
+        syslog (LOG_NOTICE, "received signal %i on %s", signum, 
 ttypath);
+        exit_code = EXIT_FAILURE;
+        slcand_running = 0;
+        break;
+    case SIGINT:
+    case SIGTERM:

slcand.c line 128

Quoted 10 lines
slcand.c +4 -1
+        syslog (LOG_NOTICE, "received signal %i on %s", signum, 
 ttypath);
+        exit_code = EXIT_SUCCESS;
+        slcand_running = 0;
         break;
     }
 }
 
-static void daemonize (const char *lockfile, char *tty)
+static int look_up_uart_speed(int s)

As my comment on GitHub, i think int isn't 32 bit or high on all platforms. So please change the datatype of parameter s to make sure the maximum like 4000000 is always reached like long or int32_t. Btw speed would be a better variable name.

Quoted 42 lines
slcand.c +42 -0
+{
+    switch (s) {
+    case 9600:
+        return B9600;
+    case 19200:
+        return B19200;
+    case 38400:
+        return B38400;
+    case 57600:
+        return B57600;
+    case 115200:
+        return B115200;
+    case 230400:
+        return B230400;
+    case 460800:
+        return B460800;
+    case 500000:
+        return B500000;
+    case 576000:
+        return B576000;
+    case 921600:
+        return B921600;
+    case 1000000:
+        return B1000000;
+    case 1152000:
+        return B1152000;
+    case 1500000:
+        return B1500000;
+    case 2000000:
+        return B2000000;
+#ifdef B2500000
+    case 2500000:
+        return B2500000;
+#endif
+#ifdef B3000000
+    case 3000000:
+        return B3000000;
+#endif
+#ifdef B3500000
+    case 3500000:
+        return B3500000;
+#endif

slcand.c line 180

Quoted 10 lines
slcand.c +10 -0
+#ifdef B3710000
+    case 3710000
+        return B3710000;
+#endif
+#ifdef B4000000
+    case 4000000:
+        return B4000000;
+#endif
+    default:
+        return B57600;

I believe it isn't a good behaviour to return 57600 in error case. So better return a special error value like -1 and handle this error case.

Quoted 40 lines
slcand.c +5 -1
+    }
+}
+
+static pid_t daemonize (const char *lockfile, char *tty, char *name)
 {
     pid_t pid, sid, parent;
     int lfp = -1;
     FILE * pFile;
+    FILE * dummyFile;
     char const *pidprefix = "/var/run/";
     char const *pidsuffix = ".pid";
-    char pidfile[PIDFILE_LENGTH];
 
     snprintf(pidfile, PIDFILE_LENGTH, "%s%s-%s%s", pidprefix, 
 DAEMON_NAME, tty, pidsuffix);

     /* already a daemon */
     if (getppid () == 1)
slcand.c +3 -1
-        return;
+        return 0;
 
     /* Create the lock file as the current user */
     if (lockfile && lockfile[0])

@@ -134,6 +214,8 @@ static void daemonize (const char *lockfile, char 
 *tty)
     }
 
     /* Trap signals that we expect to receive */
+    signal (SIGINT, child_handler);
+    signal (SIGTERM, child_handler);
     signal (SIGCHLD, child_handler);
     signal (SIGUSR1, child_handler);

     signal (SIGALRM, child_handler);
slcand.c +0 -0
@@ -152,9 +234,8 @@ static void daemonize (const char *lockfile, char 
 *tty)
 
         /* Wait for confirmation from the child via SIGTERM or

SIGCHLD, or
for two seconds to elapse (SIGALRM). pause() should not
return. */

slcand.c

Quoted 2 lines
slcand.c +1 -1
-        alarm (2);
+        alarm (5);

Please correct the comment above, if you change the seconds.

Quoted 31 lines
         pause ();
slcand.c +2 -2
-
         exit (EXIT_FAILURE);
     }

@@ -167,7 +248,8 @@ static void daemonize (const char *lockfile, char 
 *tty)
     signal (SIGTTOU, SIG_IGN);
     signal (SIGTTIN, SIG_IGN);
     signal (SIGHUP, SIG_IGN);    /* Ignore hangup signal */
-    signal (SIGTERM, SIG_DFL);    /* Die on SIGTERM */
+    signal (SIGINT, child_handler);
+    signal (SIGTERM, child_handler);
 
     /* Change the file mode mask */

     umask (0);
slcand.c +1 -1
@@ -182,7 +264,7 @@ static void daemonize (const char *lockfile, char 
 *tty)
     }
 
     pFile = fopen (pidfile,"w");
-    if (pFile == NULL)
+    if (NULL == pFile)
     {
         syslog (LOG_ERR, "unable to create pid file %s, code=%d (%s)",

             pidfile, errno, strerror (errno));
slcand.c +0 -0
@@ -201,36 +283,88 @@ static void daemonize (const char *lockfile, 
 char *tty)
     }
 
     /* Redirect standard files to /dev/null */

slcand.c static void daemonize (const char *lockfile, · line 292

Quoted 10 lines
slcand.c +4 -4
-    freopen ("/dev/null", "r", stdin);
-    freopen ("/dev/null", "w", stdout);
-    freopen ("/dev/null", "w", stderr);
+    dummyFile = freopen ("/dev/null", "r", stdin);
+    dummyFile = freopen ("/dev/null", "w", stdout);
+    dummyFile = freopen ("/dev/null", "w", stderr);
 
     /* Tell the parent process that we are A-okay */
-    kill (parent, SIGUSR1);
+    //kill (parent, SIGUSR1);

Why do you uncomment this line than remove it?

Quoted 54 lines
slcand.c +45 -1
+ return parent;
 }
 
 int main (int argc, char *argv[])
 {
     char *tty = NULL;
-    char ttypath[TTYPATH_LENGTH];
     char const *devprefix = "/dev/";
     char *name = NULL;
     char buf[IFNAMSIZ+1];
+    struct termios tios;
+    speed_t old_ispeed;
+    speed_t old_ospeed;
+
+    int opt;
+    int detach = 1;
+    int send_open = 0;
+    int send_close = 0;
+    int send_read_status_flags = 0;
+    char *speed = NULL;
+    char *uart_speed_str = NULL;
+    long int uart_speed = 0;
+    char *btr = NULL;
+    int run_as_daemon = 1;
+    pid_t parent_pid = 0;
+
+    ttypath[0] = '\0';
+
+    while ((opt = getopt(argc, argv, "ocfs:S:b:?hF")) != -1) {
+        switch (opt) {
+        case 'o':
+            send_open = 1;
+            break;
+        case 'c':
+            send_close = 1;
+            break;
+        case 'f':
+            send_read_status_flags = 1;
+            break;
+        case 's':
+            speed = optarg;
+            if (strlen(speed) > 1)
+                print_usage(argv[0]);
+            break;
+        case 'S':
+            uart_speed_str = optarg;
+            errno = 0;
+            uart_speed = strtol(uart_speed_str, NULL, 10);
+            if (errno)
+                print_usage(argv[0]);
+            break;
+        case 'b':
+            btr = optarg;
+            if (strlen(btr) > 6)

slcand.c static void daemonize (const char *lockfile, · line 355

Quoted 10 lines
slcand.c +10 -0
+                print_usage(argv[0]);
+            break;
+        case 'F':
+            run_as_daemon = 0;
+            break;
+        case 'h':
+        case '?':
+        default:
+            print_usage(argv[0]);
+            //exit(EXIT_SUCCESS);

dito

Quoted 26 lines
slcand.c +7 -9
+ break;
+        }
+    }
 
     /* Initialize the logging interface */
     openlog (DAEMON_NAME, LOG_PID, LOG_LOCAL5);
 
-    /* See how we're called */
-    if (argc == 2) {
-        tty = argv[1];
-    } else if (argc == 3) {
-        tty = argv[1];
-        name = argv[2];
-        if (strlen(name) > IFNAMSIZ-1)
-            print_usage(argv[0]);
-    } else {
+    /* Parse serial device name and optional can interface name */
+    tty = argv[optind];
+    if(NULL == tty) {
         print_usage(argv[0]);
     }
+    name = argv[optind + 1];
 
     /* Prepare the tty device name string */

     char * pch;

slcand.c int main (int argc, char *argv[]) · line 381

Quoted 6 lines
slcand.c +2 -1
@@ -243,16 +377,69 @@ int main (int argc, char *argv[])
     syslog (LOG_INFO, "starting on TTY device %s", ttypath);
 
     /* Daemonize */
-    daemonize ("/var/lock/" DAEMON_NAME, tty);
+    if(run_as_daemon) {
+        parent_pid = daemonize ("/var/lock/" DAEMON_NAME, tty, name);

I think /var/lock is a perfect candidate for a define.

Quoted 80 lines
slcand.c +54 -2
+    }
+    else {
+        /* Trap signals that we expect to receive */
+        signal (SIGINT, child_handler);
+        signal (SIGTERM, child_handler);
+    }
+
+    /* */
+    slcand_running = 1;
 
     /* Now we are a daemon -- do the work for which we were paid */
     int fd;
     int ldisc = LDISC_N_SLCAN;
 
-    if ((fd = open (ttypath, O_WRONLY | O_NOCTTY )) < 0) {
+    if ((fd = open (ttypath, O_RDWR | O_NONBLOCK | O_NOCTTY )) < 0) {
         syslog (LOG_NOTICE, "failed to open TTY device %s\n", ttypath);
         perror(ttypath);
-        exit(1);
+        exit(EXIT_FAILURE);
+    }
+
+    /* Configure baud rate */
+    memset(&tios, 0, sizeof(struct termios));
+    if(tcgetattr(fd, &tios) < 0) {
+    syslog (LOG_NOTICE, "failed to get attributes for TTY device %s: 
 %s\n", ttypath, strerror(errno));
+        exit (EXIT_FAILURE);
+    }
+
+    /* Get old values for later restore */
+    old_ispeed = cfgetispeed(&tios);
+    old_ospeed = cfgetospeed(&tios);
+
+    /* Baud Rate */
+    cfsetispeed(&tios, look_up_uart_speed(uart_speed));
+    cfsetospeed(&tios, look_up_uart_speed(uart_speed));
+
+    /* apply changes */
+    if(tcsetattr(fd, TCSADRAIN, &tios) < 0) {
+    syslog(LOG_NOTICE, "Cannot set attributes for device \"%s\": 
 %s!\n", ttypath, strerror(errno));
+    }
+
+    if (speed) {
+        sprintf(buf, "C\rS%s\r", speed);
+        if(write(fd, buf, strlen(buf)) < 0) {
+            //syslog (LO, "failed to get attributes for TTY device 
 %s: %s\n", ttypath, strerror(errno));
+
+        }
+    }
+
+    if (btr) {
+        sprintf(buf, "C\rs%s\r", btr);
+        write(fd, buf, strlen(buf));
+    }
+
+    if (send_read_status_flags) {
+        sprintf(buf, "F\r");
+        write(fd, buf, strlen(buf));
+    }
+
+    if (send_open) {
+        sprintf(buf, "O\r");
+        write(fd, buf, strlen(buf));

     }

     /* set slcan like discipline on given tty */
slcand.c +3 -2
@@ -289,14 +476,44 @@ int main (int argc, char *argv[])
             close(s);
         }
     }
+    if(parent_pid > 0) {
+        kill(parent_pid, SIGUSR1);
+    }
 
     /* The Big Loop */
-    while (1) {
-        sleep(60); /* wait 60 seconds */

slcand.c int main (int argc, char *argv[]) · line 493

Quoted 10 lines
slcand.c +10 -0
+    while (slcand_running) {
+        sleep(1); /* wait 1 second */
+    }
+
+    /* Reset line discipline */
+    syslog (LOG_INFO, "stopping on TTY device %s", ttypath);
+    ldisc = N_TTY;
+    if (ioctl (fd, TIOCSETD, &ldisc) < 0) {
+        perror("ioctl TIOCSETD");
+        exit(1);

Is here a EXIT_FAILURE missing?

Quoted 27 lines
slcand.c +20 -1
+    }
+
+    if (send_close) {
+        sprintf(buf, "C\r");
+        write(fd, buf, strlen(buf));
     }
 
+    /* Reset old rates */
+    cfsetispeed(&tios, old_ispeed);
+    cfsetospeed(&tios, old_ospeed);
+
+    /* apply changes */
+    if(tcsetattr(fd, TCSADRAIN, &tios) < 0) {
+    syslog(LOG_NOTICE, "Cannot set attributes for device \"%s\": 
 %s!\n", ttypath, strerror(errno));
+    }
+
+    /* Remove pidfile */
+    if(run_as_daemon) {
+    unlink(pidfile);
+    }
+
     /* Finish up */
     syslog (LOG_NOTICE, "terminated on %s", ttypath);
     closelog ();
-    return 0;
+    return exit_code;
Quoted 2 lines

}

Best regards

Stefan Wahren

#2 lore raw

Hi Stefan, hi Oliver,

I've implemented some suggestions and sent v2, but there are some places, where I'm not sure how it should be really implemented, so I just left comments like "Oliver?".

Quoted 89 lines · Stefan Wahren

Hello Yegor,

as requested on GitHub here are my comments:

Quoted 46 lines

slcand takes settings known from slcan_attach to configure CAN interface, like open/close channel, set bitrate etc. In addition -S option sets UART's baudrate. This way slcand combines three utilities in one: old slcand, slcan_attach and stty.

Example: slcand -o -s8 -S 3000000 ttyUSB0

Signed-off-by Yegor Yefremov <[email protected]>
---
 slcand.c |  295
+++++++++++++++++++++++++++++++++++++++++++++++++++++--------
 1 files changed, 256 insertions(+), 39 deletions(-)
slcand.c +5 -4
index 807ffaa..92ffa20 100644
@@ -40,16 +40,16 @@
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
+#include <sys/types.h>
+#include <sys/stat.h>
 #include <fcntl.h>
 #include <syslog.h>
 #include <errno.h>
 #include <pwd.h>
 #include <signal.h>
-#include <sys/socket.h>
 #include <sys/ioctl.h>
-#include <sys/types.h>
-#include <sys/stat.h>
 #include <net/if.h>
+#include <termios.h>
 
 /* default slcan line discipline since Kernel 2.6.25 */
 #define LDISC_N_SLCAN 17

@@ -69,46 +69,126 @@
 #define EXIT_SUCCESS 0
 #define EXIT_FAILURE 1
 
+
+
 void print_usage(char *prg)
 {
-    fprintf(stderr, "\nUsage: %s tty [name]\n\n", prg);

slcand.c line 82

Quoted 10 lines
slcand.c +6 -3
-    fprintf(stderr, "Example:\n");
-    fprintf(stderr, "%s ttyUSB1\n", prg);
-    fprintf(stderr, "%s ttyS0 can0\n", prg);
+    fprintf(stderr, "\nUsage: %s [options] <tty> [canif-name]\n\n", prg);
+    fprintf(stderr, "Options: -o         (send open command 'O\\r')\n");
+    fprintf(stderr, "         -c         (send close command 'C\\r')\n");
+    fprintf(stderr, "         -f         (read status flags with 'F\\r'
 to reset error states)\n");
+    fprintf(stderr, "         -s <speed> (set CAN speed 0..8)\n");
+    fprintf(stderr, "         -S <speed> (set UART speed)\n");

It would be nice for the user to know the range of the UART speed and it is in baud.

Quoted 24 lines
slcand.c +13 -2
+ fprintf(stderr, "         -b <btr>   (set bit time register value)\n");
+    fprintf(stderr, "         -F         (stay in foreground; no
 daemonize)\n");
+    fprintf(stderr, "         -h         (show this help page)\n");
+    fprintf(stderr, "\nExamples:\n");
+    fprintf(stderr, "slcand -o -c -f -s6 ttyslcan0\n");
+    fprintf(stderr, "slcand -o -c -f -s6 ttyslcan0 can0\n");
     fprintf(stderr, "\n");
     exit(EXIT_FAILURE);
 }
 
+
+static int slcand_running = 0;
+static int exit_code = 0;
+static char ttypath[TTYPATH_LENGTH];
+static char pidfile[PIDFILE_LENGTH];
+
+
 static void child_handler (int signum)
 {
     switch (signum)
     {
-    case SIGALRM:
-        exit (EXIT_FAILURE);
Quoted 8 lines

slcand.c line 107

Quoted 5 lines
slcand.c +2 -2
-        break;
     case SIGUSR1:
-        exit (EXIT_SUCCESS);
+        /* exit parent */
+        exit(EXIT_SUCCESS);

Please try to keep code convention.

Fixed

Quoted 17 lines
Quoted 17 lines
slcand.c +10 -1
 break;
+    case SIGALRM:
     case SIGCHLD:
-        exit (EXIT_FAILURE);
+        syslog (LOG_NOTICE, "received signal %i on %s", signum, ttypath);
+        exit_code = EXIT_FAILURE;
+        slcand_running = 0;
+        break;
+    case SIGINT:
+    case SIGTERM:
+        syslog (LOG_NOTICE, "received signal %i on %s", signum, ttypath);
+        exit_code = EXIT_SUCCESS;
+        slcand_running = 0;
         break;
     }
 }
Quoted 8 lines

slcand.c line 124

Quoted 2 lines
slcand.c +1 -1
-static void daemonize (const char *lockfile, char *tty)
+static int look_up_uart_speed(int s)

As my comment on GitHub, i think int isn't 32 bit or high on all platforms. So please change the datatype of parameter s to make sure the maximum like 4000000 is always reached like long or int32_t. Btw speed would be a better variable name.

Fixed. speed refers to CAN speed.

Quoted 48 lines
Quoted 48 lines
slcand.c +48 -0
+{
+    switch (s) {
+    case 9600:
+        return B9600;
+    case 19200:
+        return B19200;
+    case 38400:
+        return B38400;
+    case 57600:
+        return B57600;
+    case 115200:
+        return B115200;
+    case 230400:
+        return B230400;
+    case 460800:
+        return B460800;
+    case 500000:
+        return B500000;
+    case 576000:
+        return B576000;
+    case 921600:
+        return B921600;
+    case 1000000:
+        return B1000000;
+    case 1152000:
+        return B1152000;
+    case 1500000:
+        return B1500000;
+    case 2000000:
+        return B2000000;
+#ifdef B2500000
+    case 2500000:
+        return B2500000;
+#endif
+#ifdef B3000000
+    case 3000000:
+        return B3000000;
+#endif
+#ifdef B3500000
+    case 3500000:
+        return B3500000;
+#endif
+#ifdef B3710000
+    case 3710000
+        return B3710000;
+#endif
+#ifdef B4000000
+    case 4000000:
Quoted 8 lines

slcand.c line 176

Quoted 4 lines
slcand.c +4 -0
+        return B4000000;
+#endif
+    default:
+        return B57600;

I believe it isn't a good behaviour to return 57600 in error case. So better return a special error value like -1 and handle this error case.

Fixed

Quoted 36 lines
Quoted 36 lines
slcand.c +6 -2
+    }
+}
+
+static pid_t daemonize (const char *lockfile, char *tty, char *name)
 {
     pid_t pid, sid, parent;
     int lfp = -1;
     FILE * pFile;
+    FILE * dummyFile;
     char const *pidprefix = "/var/run/";
     char const *pidsuffix = ".pid";
-    char pidfile[PIDFILE_LENGTH];
 
     snprintf(pidfile, PIDFILE_LENGTH, "%s%s-%s%s", pidprefix,
 DAEMON_NAME, tty, pidsuffix);
 
     /* already a daemon */
     if (getppid () == 1)
-        return;
+        return 0;

     /* Create the lock file as the current user */
     if (lockfile && lockfile[0])
slcand.c +2 -0
@@ -134,6 +214,8 @@ static void daemonize (const char *lockfile, char
 *tty)
     }
 
     /* Trap signals that we expect to receive */
+    signal (SIGINT, child_handler);
+    signal (SIGTERM, child_handler);
     signal (SIGCHLD, child_handler);
     signal (SIGUSR1, child_handler);

     signal (SIGALRM, child_handler);
slcand.c +0 -0
@@ -152,9 +234,8 @@ static void daemonize (const char *lockfile, char
 *tty)
Quoted 9 lines

slcand.c

Quoted 6 lines
slcand.c +0 -0
         /* Wait for confirmation from the child via SIGTERM or SIGCHLD,

or
for two seconds to elapse (SIGALRM). pause() should not
return. */

slcand.c +1 -1
-        alarm (2);
+        alarm (5);

Please correct the comment above, if you change the seconds.

Fixed. s/two/five

Quoted 38 lines
Quoted 38 lines
         pause ();
slcand.c +2 -2
-
         exit (EXIT_FAILURE);
     }

@@ -167,7 +248,8 @@ static void daemonize (const char *lockfile, char
 *tty)
     signal (SIGTTOU, SIG_IGN);
     signal (SIGTTIN, SIG_IGN);
     signal (SIGHUP, SIG_IGN);    /* Ignore hangup signal */
-    signal (SIGTERM, SIG_DFL);    /* Die on SIGTERM */
+    signal (SIGINT, child_handler);
+    signal (SIGTERM, child_handler);
 
     /* Change the file mode mask */

     umask (0);
slcand.c +1 -1
@@ -182,7 +264,7 @@ static void daemonize (const char *lockfile, char
 *tty)
     }
 
     pFile = fopen (pidfile,"w");
-    if (pFile == NULL)
+    if (NULL == pFile)
     {
         syslog (LOG_ERR, "unable to create pid file %s, code=%d (%s)",

             pidfile, errno, strerror (errno));
slcand.c +3 -3
@@ -201,36 +283,88 @@ static void daemonize (const char *lockfile, char
 *tty)
     }
 
     /* Redirect standard files to /dev/null */
-    freopen ("/dev/null", "r", stdin);
-    freopen ("/dev/null", "w", stdout);
-    freopen ("/dev/null", "w", stderr);
+    dummyFile = freopen ("/dev/null", "r", stdin);
+    dummyFile = freopen ("/dev/null", "w", stdout);
+    dummyFile = freopen ("/dev/null", "w", stderr);
Quoted 6 lines

slcand.c static void daemonize (const char *lockfile, char · line 292

Quoted 3 lines
slcand.c +1 -1
     /* Tell the parent process that we are A-okay */
-    kill (parent, SIGUSR1);
+    //kill (parent, SIGUSR1);

Why do you uncomment this line than remove it?

Oliver?

Quoted 59 lines
Quoted 59 lines
slcand.c +50 -1
+ return parent;
 }
 
 int main (int argc, char *argv[])
 {
     char *tty = NULL;
-    char ttypath[TTYPATH_LENGTH];
     char const *devprefix = "/dev/";
     char *name = NULL;
     char buf[IFNAMSIZ+1];
+    struct termios tios;
+    speed_t old_ispeed;
+    speed_t old_ospeed;
+
+    int opt;
+    int detach = 1;
+    int send_open = 0;
+    int send_close = 0;
+    int send_read_status_flags = 0;
+    char *speed = NULL;
+    char *uart_speed_str = NULL;
+    long int uart_speed = 0;
+    char *btr = NULL;
+    int run_as_daemon = 1;
+    pid_t parent_pid = 0;
+
+    ttypath[0] = '\0';
+
+    while ((opt = getopt(argc, argv, "ocfs:S:b:?hF")) != -1) {
+        switch (opt) {
+        case 'o':
+            send_open = 1;
+            break;
+        case 'c':
+            send_close = 1;
+            break;
+        case 'f':
+            send_read_status_flags = 1;
+            break;
+        case 's':
+            speed = optarg;
+            if (strlen(speed) > 1)
+                print_usage(argv[0]);
+            break;
+        case 'S':
+            uart_speed_str = optarg;
+            errno = 0;
+            uart_speed = strtol(uart_speed_str, NULL, 10);
+            if (errno)
+                print_usage(argv[0]);
+            break;
+        case 'b':
+            btr = optarg;
+            if (strlen(btr) > 6)
+                print_usage(argv[0]);
+            break;
+        case 'F':
+            run_as_daemon = 0;
+            break;
Quoted 8 lines

slcand.c static void daemonize (const char *lockfile, char · line 355

Quoted 5 lines
slcand.c +5 -0
+        case 'h':
+        case '?':
+        default:
+            print_usage(argv[0]);
+            //exit(EXIT_SUCCESS);

dito

Oliver?

Quoted 28 lines
Quoted 28 lines
slcand.c +7 -9
+ break;
+        }
+    }
 
     /* Initialize the logging interface */
     openlog (DAEMON_NAME, LOG_PID, LOG_LOCAL5);
 
-    /* See how we're called */
-    if (argc == 2) {
-        tty = argv[1];
-    } else if (argc == 3) {
-        tty = argv[1];
-        name = argv[2];
-        if (strlen(name) > IFNAMSIZ-1)
-            print_usage(argv[0]);
-    } else {
+    /* Parse serial device name and optional can interface name */
+    tty = argv[optind];
+    if(NULL == tty) {
         print_usage(argv[0]);
     }
+    name = argv[optind + 1];
 
     /* Prepare the tty device name string */

     char * pch;
slcand.c +0 -0
@@ -243,16 +377,69 @@ int main (int argc, char *argv[])
     syslog (LOG_INFO, "starting on TTY device %s", ttypath);
Quoted 7 lines

slcand.c int main (int argc, char *argv[]) · line 381

Quoted 4 lines
slcand.c +2 -1
     /* Daemonize */
-    daemonize ("/var/lock/" DAEMON_NAME, tty);
+    if(run_as_daemon) {
+        parent_pid = daemonize ("/var/lock/" DAEMON_NAME, tty, name);

I think /var/lock is a perfect candidate for a define.

Oliver?

Quoted 77 lines
Quoted 77 lines
slcand.c +54 -2
+    }
+    else {
+        /* Trap signals that we expect to receive */
+        signal (SIGINT, child_handler);
+        signal (SIGTERM, child_handler);
+    }
+
+    /* */
+    slcand_running = 1;
 
     /* Now we are a daemon -- do the work for which we were paid */
     int fd;
     int ldisc = LDISC_N_SLCAN;
 
-    if ((fd = open (ttypath, O_WRONLY | O_NOCTTY )) < 0) {
+    if ((fd = open (ttypath, O_RDWR | O_NONBLOCK | O_NOCTTY )) < 0) {
         syslog (LOG_NOTICE, "failed to open TTY device %s\n", ttypath);
         perror(ttypath);
-        exit(1);
+        exit(EXIT_FAILURE);
+    }
+
+    /* Configure baud rate */
+    memset(&tios, 0, sizeof(struct termios));
+    if(tcgetattr(fd, &tios) < 0) {
+    syslog (LOG_NOTICE, "failed to get attributes for TTY device %s:
 %s\n", ttypath, strerror(errno));
+        exit (EXIT_FAILURE);
+    }
+
+    /* Get old values for later restore */
+    old_ispeed = cfgetispeed(&tios);
+    old_ospeed = cfgetospeed(&tios);
+
+    /* Baud Rate */
+    cfsetispeed(&tios, look_up_uart_speed(uart_speed));
+    cfsetospeed(&tios, look_up_uart_speed(uart_speed));
+
+    /* apply changes */
+    if(tcsetattr(fd, TCSADRAIN, &tios) < 0) {
+    syslog(LOG_NOTICE, "Cannot set attributes for device \"%s\": %s!\n",
 ttypath, strerror(errno));
+    }
+
+    if (speed) {
+        sprintf(buf, "C\rS%s\r", speed);
+        if(write(fd, buf, strlen(buf)) < 0) {
+            //syslog (LO, "failed to get attributes for TTY device %s:
 %s\n", ttypath, strerror(errno));
+
+        }
+    }
+
+    if (btr) {
+        sprintf(buf, "C\rs%s\r", btr);
+        write(fd, buf, strlen(buf));
+    }
+
+    if (send_read_status_flags) {
+        sprintf(buf, "F\r");
+        write(fd, buf, strlen(buf));
+    }
+
+    if (send_open) {
+        sprintf(buf, "O\r");
+        write(fd, buf, strlen(buf));

     }

     /* set slcan like discipline on given tty */
slcand.c +3 -0
@@ -289,14 +476,44 @@ int main (int argc, char *argv[])
             close(s);
         }
     }
+    if(parent_pid > 0) {
+        kill(parent_pid, SIGUSR1);
+    }
Quoted 16 lines

slcand.c int main (int argc, char *argv[]) · line 493

Quoted 13 lines
slcand.c +10 -2
     /* The Big Loop */
-    while (1) {
-        sleep(60); /* wait 60 seconds */
+    while (slcand_running) {
+        sleep(1); /* wait 1 second */
+    }
+
+    /* Reset line discipline */
+    syslog (LOG_INFO, "stopping on TTY device %s", ttypath);
+    ldisc = N_TTY;
+    if (ioctl (fd, TIOCSETD, &ldisc) < 0) {
+        perror("ioctl TIOCSETD");
+        exit(1);

Is here a EXIT_FAILURE missing?

Oliver?

Quoted 20 lines
Quoted 20 lines
slcand.c +17 -0
+    }
+
+    if (send_close) {
+        sprintf(buf, "C\r");
+        write(fd, buf, strlen(buf));
     }
 
+    /* Reset old rates */
+    cfsetispeed(&tios, old_ispeed);
+    cfsetospeed(&tios, old_ospeed);
+
+    /* apply changes */
+    if(tcsetattr(fd, TCSADRAIN, &tios) < 0) {
+    syslog(LOG_NOTICE, "Cannot set attributes for device \"%s\": %s!\n",
 ttypath, strerror(errno));
+    }
+
+    /* Remove pidfile */
+    if(run_as_daemon) {
+    unlink(pidfile);
Quoted 8 lines
Quoted 8 lines
slcand.c +3 -1
+    }
+
     /* Finish up */
     syslog (LOG_NOTICE, "terminated on %s", ttypath);
     closelog ();
-    return 0;
+    return exit_code;

}

Yegor