avrdude: Fixes in error handling

xs/src/avrdude/avr.c

@@ -1034,6 +1034,7 @@ int avr_write(PROGRAMMER * pgm, AVRPART * p, char * memtype, int size,
        * error, otherwise it gets cleared in avr_write_byte()
        */
       pgm->err_led(pgm, ON);
+      return -1;
     }
   }
 

xs/src/avrdude/ser_posix.c

@@ -47,6 +47,7 @@
 #include "libavrdude.h"
 
 long serial_recv_timeout = 5000; /* ms */
+#define MAX_ZERO_READS 512
 
 struct baud_mapping {
   long baud;
@@ -363,6 +364,7 @@ static int ser_recv(union filedescriptor *fd, unsigned char * buf, size_t buflen
   int rc;
   unsigned char * p = buf;
   size_t len = 0;
+  unsigned zero_reads = 0;
 
   timeout.tv_sec  = serial_recv_timeout / 1000L;
   timeout.tv_usec = (serial_recv_timeout % 1000L) * 1000;
@@ -397,9 +399,18 @@ static int ser_recv(union filedescriptor *fd, unsigned char * buf, size_t buflen
       avrdude_message(MSG_INFO, "%s: ser_recv(): read error: %s\n",
               progname, strerror(errno));
       return -1;
+    } else if (rc == 0) {
+      zero_reads++;
+      if (zero_reads > MAX_ZERO_READS) {
+        avrdude_message(MSG_NOTICE2, "%s: ser_recv(): programmer is not responding (too many zero reads)\n",
+                progname);
+        return -1;
+      }
+    } else {
+      zero_reads = 0;
+      p += rc;
+      len += rc;
     }
-    p += rc;
-    len += rc;
   }
 
   p = buf;
@@ -435,6 +446,7 @@ static int ser_drain(union filedescriptor *fd, int display)
   int nfds;
   int rc;
   unsigned char buf;
+  unsigned zero_reads = 0;
 
   timeout.tv_sec = 0;
   timeout.tv_usec = 250000;
@@ -472,6 +484,15 @@ static int ser_drain(union filedescriptor *fd, int display)
       avrdude_message(MSG_INFO, "%s: ser_drain(): read error: %s\n",
               progname, strerror(errno));
       return -1;
+    } else if (rc == 0) {
+      zero_reads++;
+      if (zero_reads > MAX_ZERO_READS) {
+        avrdude_message(MSG_NOTICE2, "%s: ser_drain(): programmer is not responding (too many zero reads)\n",
+                progname);
+        return -1;
+      }
+    } else {
+      zero_reads = 0;
     }
     if (display) {
       avrdude_message(MSG_INFO, "%02x ", buf);

xs/src/avrdude/stk500v2.c

@@ -518,7 +518,7 @@ static int stk500v2_send(PROGRAMMER * pgm, unsigned char * data, size_t len)
   DEBUG(", %d)\n",len+6);
 
   if (serial_send(&pgm->fd, buf, len+6) != 0) {
-    avrdude_message(MSG_INFO, "%s: stk500_send(): failed to send command to serial port\n",progname);
+    avrdude_message(MSG_INFO, "%s: stk500v2_send(): failed to send command to serial port\n",progname);
     return -1;
   }
 
@@ -731,7 +731,7 @@ static int stk500v2_recv(PROGRAMMER * pgm, unsigned char *msg, size_t maxsize) {
      tnow = tv.tv_sec;
      if (tnow-tstart > timeoutval) {			// wuff - signed/unsigned/overflow
       timedout:
-       avrdude_message(MSG_INFO, "%s: stk500v2_ReceiveMessage(): timeout\n",
+       avrdude_message(MSG_INFO, "%s: stk500v2_recv(): timeout\n",
                progname);
        return -1;
      }
@@ -744,7 +744,7 @@ static int stk500v2_recv(PROGRAMMER * pgm, unsigned char *msg, size_t maxsize) {
 
 
 
-int stk500v2_getsync(PROGRAMMER * pgm) {
+static int stk500v2_getsync_internal(PROGRAMMER * pgm, int retries) {
   int tries = 0;
   unsigned char buf[1], resp[32];
   int status;
@@ -760,7 +760,10 @@ retry:
 
   // send the sync command and see if we can get there
   buf[0] = CMD_SIGN_ON;
-  stk500v2_send(pgm, buf, 1);
+  if (stk500v2_send(pgm, buf, 1) != 0) {
+    avrdude_message(MSG_INFO, "%s: stk500v2_getsync(): can't communicate with device\n", progname);
+    return -1;
+  }
 
   // try to get the response back and see where we got
   status = stk500v2_recv(pgm, resp, sizeof(resp));
@@ -794,7 +797,7 @@ retry:
                         progname, pgmname[PDATA(pgm)->pgmtype]);
       return 0;
     } else {
-      if (tries > RETRIES) {
+      if (tries > retries) {
         avrdude_message(MSG_INFO, "%s: stk500v2_getsync(): can't communicate with device: resp=0x%02x\n",
                         progname, resp[0]);
         return -6;
@@ -804,7 +807,7 @@ retry:
 
   // or if we got a timeout
   } else if (status == -1) {
-    if (tries > RETRIES) {
+    if (tries > retries) {
       avrdude_message(MSG_INFO, "%s: stk500v2_getsync(): timeout communicating with programmer\n",
               progname);
       return -1;
@@ -813,7 +816,7 @@ retry:
 
   // or any other error
   } else {
-    if (tries > RETRIES) {
+    if (tries > retries) {
       avrdude_message(MSG_INFO, "%s: stk500v2_getsync(): error communicating with programmer: (%d)\n",
               progname,status);
     } else
@@ -823,6 +826,11 @@ retry:
   return 0;
 }
 
+int stk500v2_getsync(PROGRAMMER * pgm) {
+  // This is to avoid applying RETRIES exponentially
+  return stk500v2_getsync_internal(pgm, RETRIES);
+}
+
 static int stk500v2_command(PROGRAMMER * pgm, unsigned char * buf,
                             size_t len, size_t maxlen) {
   int i;
@@ -837,7 +845,11 @@ retry:
   tries++;
 
   // send the command to the programmer
-  stk500v2_send(pgm,buf,len);
+  if (stk500v2_send(pgm, buf, len) != 0) {
+    avrdude_message(MSG_INFO, "%s: stk500v2_command(): can't communicate with device\n", progname);
+    return -1;
+  }
+
   // attempt to read the status back
   status = stk500v2_recv(pgm,buf,maxlen);
 
@@ -922,7 +934,7 @@ retry:
   }
 
   // otherwise try to sync up again
-  status = stk500v2_getsync(pgm);
+  status = stk500v2_getsync_internal(pgm, 1);
   if (status != 0) {
     if (tries > RETRIES) {
       avrdude_message(MSG_INFO, "%s: stk500v2_command(): failed miserably to execute command 0x%02x\n",
@@ -1123,7 +1135,7 @@ static int stk500v2_program_enable(PROGRAMMER * pgm, AVRPART * p)
       stk500v2_setparm_real(pgm, PARAM_RESET_POLARITY, 0x01);
 
   tries = 0;
-retry:
+// retry:
   buf[0] = CMD_ENTER_PROGMODE_ISP;
   buf[1] = p->timeout;
   buf[2] = p->stabdelay;