Be more robust detecting initial comms errors.

Handle larger comment strings from Meridian.

diff --git a/gpsbabel/magproto.c b/gpsbabel/magproto.c
index e23cdbab630d8d9e51e7eee2a073277566c2a9bf..a46c62dc73efc0631e61bfb4adca4c69f766783e 100644 (file)
--- a/gpsbabel/magproto.c
+++ b/gpsbabel/magproto.c
@@ -21,11 +21,12 @@
 
 #include <termios.h>
 #include <ctype.h>
+#include <time.h>
 
 #include "defs.h"
 #include "magellan.h"
 
-#define debug 1
+#define debug 0
 
 typedef enum {
        mrs_handoff = 0,
@@ -39,6 +40,7 @@ static struct termios orig_tio;
 static int last_rx_csum;
 static int found_done;
 static icon_mapping_t *icon_mapping;
+static int got_version;
 
 static waypoint * mag_wptparse(char *);
 
@@ -175,7 +177,7 @@ fprintf(stderr, "E");
 static void
 mag_writeack(int osum)
 {
-       char obuf[100];
+       char obuf[200];
        snprintf(obuf, sizeof(obuf), "PMGNCSM,%02X", osum);
        mag_writemsg(obuf);
 }
@@ -200,6 +202,8 @@ mag_verparse(char *ibuf)
        int prodid = mm_unknown; 
        char version[1024];
        pid_to_model_t *pp = pid_to_model;
+
+       got_version = 1;
        sscanf(ibuf,"$PMGNVER,%d,%[^,]", &prodid, version);
 
        for (pp = pid_to_model; pp->model ; pp++) {
@@ -226,15 +230,23 @@ mag_verparse(char *ibuf)
 static void
 mag_readmsg(void)
 {
-       char ibuf[100];
+       char ibuf[200];
        int isz;
        unsigned int isum;
        char *isump;
-       fgets(ibuf, sizeof(ibuf), magfile);
+       char *gr;
+
+       gr = fgets(ibuf, sizeof(ibuf), magfile);
+
+       if (!gr && !got_version) {
+               fatal("Magproto: No data received from GPS.\n");
+       }
+
        isz = strlen(ibuf);
+
        if (isz < 5) {
-if (debug)
-fprintf(stderr, "SHORT READ %d\n", isz);
+               if (debug)
+                       fprintf(stderr, "SHORT READ %d\n", isz);
                return;
        }
        while (!isprint(ibuf[isz]))
@@ -244,6 +256,10 @@ fprintf(stderr, "SHORT READ %d\n", isz);
        if (isum != mag_pchecksum(&ibuf[1], isz-3)) {
 if (debug)
                fprintf(stderr, "RXERR %02x/%02x: '%s'\n", isum, mag_pchecksum(&ibuf[1],isz-5), ibuf);
+               /* Special case receive errors early on. */
+               if (!got_version) {
+                       fatal("Magproto: bad communication.  Check bit rate.\n");
+               }
        }
 if (debug)
 fprintf(stderr, "READ: %s\n", ibuf);
@@ -270,6 +286,8 @@ static void
 mag_rd_init(const char *portname)
 {
        struct termios new_tio;
+       time_t now, later;
+
        magfile = fopen(portname, "rw+b");
        
        if (magfile == NULL) {
@@ -286,13 +304,26 @@ mag_rd_init(const char *portname)
        new_tio.c_lflag &= ~(ECHO|ECHONL|ICANON|ISIG|IEXTEN);
        new_tio.c_cflag &= ~(CSIZE|PARENB);
        new_tio.c_cflag |= CS8;
+       new_tio.c_cc[VTIME] = 10;
+       new_tio.c_cc[VMIN] = 0;
 
        cfsetospeed(&new_tio, B4800);
        cfsetispeed(&new_tio, B4800);
        tcsetattr(magfd, TCSAFLUSH, &new_tio);
        
        mag_handon();
+       now = time(NULL);
+       later = now + 2;
        mag_writemsg("PMGNCMD,VERSION");
+
+       while (!got_version) {
+               mag_readmsg();
+               if (time(NULL) > later) {
+                       fatal("Magproto: No acknowledgment from GPS on %s\n",
+                               portname);
+               }
+       }
+
        mag_writemsg("PMGNCMD,NMEAOFF");
        return;
 }