slcand : added new commandline option to support direct assignment of a CAN

netdevice name to the given tty (by renaming the created netdevice).

Signed-off-by: Robert Haddon <robert.haddon@cirrascale.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
git-svn-id: svn://svn.berlios.de//socketcan/trunk@1213 030b6a49-0b11-0410-94ab-b0dab22257f2

diff --git a/can-utils/slcand.c b/can-utils/slcand.c
index f84435f1d5fb50e1db753978ca8be905733f1ba5..0d55a11c663ad98a9d54cc055586d436c7a7c3cc 100644 (file)
--- a/can-utils/slcand.c
+++ b/can-utils/slcand.c
@@ -52,6 +52,7 @@
 #include <pwd.h>
 #include <signal.h>
 #include <sys/ioctl.h>
+#include <net/if.h>
 
 /* default slcan line discipline since Kernel 2.6.25 */
 #define LDISC_N_SLCAN 17
@@ -67,10 +68,10 @@
 
 void print_usage(char *prg)
 {
-       fprintf(stderr, "\nUsage: %s tty\n\n", prg);
+       fprintf(stderr, "\nUsage: %s tty [name]\n\n", prg);
        fprintf(stderr, "Example:\n");
        fprintf(stderr, "%s ttyUSB1\n", prg);
-       fprintf(stderr, "%s ttyS0\n", prg);
+       fprintf(stderr, "%s ttyS0 can0\n", prg);
        fprintf(stderr, "\n");
        exit(EXIT_FAILURE);
 }
@@ -91,7 +92,7 @@ static void child_handler (int signum)
        }
 }
 
-static void daemonize (const char *lockfile, char *tty)
+static void daemonize (const char *lockfile, char *tty, char *name)
 {
        pid_t pid, sid, parent;
        int lfp = -1;
@@ -124,7 +125,7 @@ static void daemonize (const char *lockfile, char *tty)
                struct passwd *pw = getpwnam (RUN_AS_USER);
                if (pw)
                {
-                       syslog (LOG_NOTICE, "setting user to " RUN_AS_USER);
+                       //syslog (LOG_NOTICE, "setting user to " RUN_AS_USER);
                        setuid (pw->pw_uid);
                }
        }
@@ -207,17 +208,26 @@ static void daemonize (const char *lockfile, char *tty)
 
 int main (int argc, char *argv[])
 {
-       char *tty;
+       char *tty = NULL;
        char *ttypath;
        char const *devprefix = "/dev/";
+       char *name = NULL;
+       char buf[IFNAMSIZ+1];
 
        /* Initialize the logging interface */
        openlog (DAEMON_NAME, LOG_PID, LOG_LOCAL5);
 
        /* See how we're called */
-       if (argc != 2)
+       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 {
                print_usage(argv[0]);
-       tty = argv[1];
+       }
 
        /* Prepare the tty device name string */
        char * pch;
@@ -230,22 +240,53 @@ int main (int argc, char *argv[])
        syslog (LOG_INFO, "starting on TTY device %s", ttypath);
 
        /* Daemonize */
-       daemonize ("/var/lock/" DAEMON_NAME, tty);
+       daemonize ("/var/lock/" DAEMON_NAME, tty, name);
 
        /* 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) {
+           syslog (LOG_NOTICE, "failed to open TTY device %s\n", ttypath);
                perror(ttypath);
                exit(1);
        }
 
+       /* set slcan like discipline on given tty */
        if (ioctl (fd, TIOCSETD, &ldisc) < 0) {
-               perror("ioctl");
+               perror("ioctl TIOCSETD");
+               exit(1);
+       }
+       
+       /* retrieve the name of the created CAN netdevice */
+       if (ioctl (fd, SIOCGIFNAME, buf) < 0) {
+               perror("ioctl SIOCGIFNAME");
                exit(1);
        }
 
+       syslog (LOG_NOTICE, "attached TTY %s to netdevice %s\n", ttypath, buf);
+       
+       /* try to rename the created netdevice */
+       if (name) {
+               struct ifreq ifr;
+               int s = socket(PF_INET, SOCK_DGRAM, 0);
+               if (s < 0)
+                       perror("socket for interface rename");
+               else {
+                       strncpy (ifr.ifr_name, buf, IFNAMSIZ);
+                       strncpy (ifr.ifr_newname, name, IFNAMSIZ);
+
+                       if (ioctl(s, SIOCSIFNAME, &ifr) < 0) {
+                               syslog (LOG_NOTICE, "netdevice %s rename to %s failed\n", buf, name);
+                               perror("ioctl SIOCSIFNAME rename");
+                exit(1);
+                       } else
+                               syslog (LOG_NOTICE, "netdevice %s renamed to %s\n", buf, name);
+
+                       close(s);
+               }       
+       }
+
        /* The Big Loop */
        while (1) {
                sleep(60); /* wait 60 seconds */