can-utils: AOSP build clean up

[sojka/can-utils.git] / slcanpty.c

diff --git a/slcanpty.c b/slcanpty.c
index f3628b9e9701c260d5d86eafa31d5750c31dbe26..2c1cabea262f2b80f10a40bd9cf912a7c03a2a7b 100644 (file)
--- a/slcanpty.c
+++ b/slcanpty.c
@@ -64,7 +64,7 @@ static int asc2nibble(char c)
 
 /* read data from pty, send CAN frames to CAN socket and answer commands */
 int pty2can(int pty, int socket, struct can_filter *fi,
-              int *is_open, int *tstamp)
+           int *is_open, int *tstamp)
 {
        int nbytes;
        char cmd;
@@ -73,13 +73,21 @@ int pty2can(int pty, int socket, struct can_filter *fi,
        int ptr;
        struct can_frame frame;
        int tmp, i;
+       static int rxoffset = 0; /* points to the end of an received incomplete SLCAN message */
+
+       nbytes = read(pty, &buf[rxoffset], sizeof(buf)-rxoffset-1);
+       if (nbytes <= 0) {
+               /* nbytes == 0 : no error but pty decriptor has been closed */
+               if (nbytes < 0)
+                       perror("read pty");
 
-       nbytes = read(pty, &buf, sizeof(buf)-1);
-       if (nbytes < 0) {
-               perror("read pty");
                return 1;
        }
 
+       /* reset incomplete message offset */
+       nbytes += rxoffset;
+       rxoffset = 0;
+
 rx_restart:
        /* remove trailing '\r' characters to be robust against some apps */
        while (buf[0] == '\r' && nbytes > 0) {
@@ -91,6 +99,21 @@ rx_restart:
        if (!nbytes)
                return 0;
 
+       /* check if we can detect a complete SLCAN message including '\r' */
+       for (tmp = 0; tmp < nbytes; tmp++) {
+               if (buf[tmp] == '\r')
+                       break;
+       }
+
+       /* no '\r' found in the message buffer? */
+       if (tmp == nbytes) {
+               /* save incomplete message */
+               rxoffset = nbytes;
+
+               /* leave here and read from pty again */
+               return 0;
+       }
+
        cmd = buf[0];
        buf[nbytes] = 0;
 
@@ -363,6 +386,27 @@ int can2pty(int pty, int socket, int *tstamp)
        return 0;
 }
 
+int check_select_stdin(void)
+{
+       fd_set rdfs;
+       struct timeval timeout;
+       int ret;
+
+       FD_ZERO(&rdfs);
+       FD_SET(0, &rdfs);
+       timeout.tv_sec = 0;
+       timeout.tv_usec = 0;
+
+       ret = select(1, &rdfs, NULL, NULL, &timeout);
+
+       if (ret < 0)
+               return 0; /* not selectable */
+
+       if (ret > 0 && getchar() == EOF)
+               return 0; /* EOF, eg. /dev/null */
+
+       return 1;
+}
 
 int main(int argc, char **argv)
 {
@@ -372,6 +416,7 @@ int main(int argc, char **argv)
        struct sockaddr_can addr;
        struct termios topts;
        struct ifreq ifr;
+       int select_stdin = 0;
        int running = 1;
        int tstamp = 0;
        int is_open = 0;
@@ -393,6 +438,8 @@ int main(int argc, char **argv)
                return 1;
        }
 
+       select_stdin = check_select_stdin();
+
        /* open pty */
        p = open(argv[1], O_RDWR);
        if (p < 0) {
@@ -407,7 +454,9 @@ int main(int argc, char **argv)
 
        /* disable local echo which would cause double frames */
        topts.c_lflag &= ~(ICANON | ECHO | ECHOE | ECHOK |
-                          ECHONL | ECHOPRT | ECHOKE | ICRNL);
+                          ECHONL | ECHOPRT | ECHOKE);
+       topts.c_iflag &= ~(ICRNL);
+       topts.c_iflag |= INLCR;
        tcsetattr(p, TCSANOW, &topts);
 
        /* Support for the Unix 98 pseudo-terminal interface /dev/ptmx /dev/pts/N */
@@ -464,7 +513,10 @@ int main(int argc, char **argv)
        while (running) {
 
                FD_ZERO(&rdfs);
-               FD_SET(0, &rdfs);
+
+               if (select_stdin)
+                       FD_SET(0, &rdfs);
+
                FD_SET(p, &rdfs);
                FD_SET(s, &rdfs);