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Return-Path: <somewhere!brad@cayman.cayman.com>
Date: Fri, 10 Feb 89 08:25:42 EST
From: brad%cayman@harvard.harvard.edu (Brad Parker)
To: bug-gcc@prep.ai.mit.edu
Subject: gdb 3.x / some diffs to remote.c 


I started using the gdb 3.0 "remote" option with a 9600 baud serial line
to a target (the GatorBox). I found some simple bugs - this is so obscure that
no one may use this, but I do! These patches fix a retry checksum bug and
cause the packet code to retry which makes it more robust.

I added the simple fixes from the gdb 3.1 patches.

I also have the "nub" which runs in the remote system. If any one would like
a copy, let me know.

-brad
Brad Parker
Cayman Systems, Inc.
brad@cayman.com
---- cut here ----

*** remote.c.orig	Fri Feb 10 08:03:54 1989
--- remote.c	Fri Feb 10 08:21:11 1989
***************
*** 94,100 ****
  #define TERMINAL struct sgttyb
  #endif
  
! int kiodebug;
  
  int icache;
  
--- 94,101 ----
  #define TERMINAL struct sgttyb
  #endif
  
! static int kiodebug = 0;
! static int timeout = 5;
  
  int icache;
  
***************
*** 101,107 ****
  /* Descriptor for I/O to remote machine.  */
  int remote_desc;
  
! #define	PBUFSIZ	300
  
  static void remote_send ();
  static void putpkt ();
--- 102,108 ----
  /* Descriptor for I/O to remote machine.  */
  int remote_desc;
  
! #define	PBUFSIZ	400
  
  static void remote_send ();
  static void putpkt ();
***************
*** 109,114 ****
--- 110,126 ----
  static void dcache_flush ();
  
  
+ /* called when SIGALRM signal sent due to alarm() timeout */
+ 
+ void
+ remote_timer()
+ {
+ 	if (kiodebug)
+ 		printf("[remote_timer]\n");
+ 
+ 	alarm(timeout);
+ }
+ 
  /* Open a connection to a remote debugger.
     NAME is the filename used for communication.  */
  
***************
*** 137,142 ****
--- 149,162 ----
    if (from_tty)
      printf ("Remote debugging using %s\n", name);
    remote_debugging = 1;
+ 
+   /* cause SIGALRM's to make reads fail */
+   if (siginterrupt(SIGALRM, 1) != 0)
+ 	perror("[remote_open] siginterrupt");
+ 
+   /* set up read timeout timer */
+   if (signal(SIGALRM, remote_timer) == (void (*))-1)
+ 	perror("[remote_open] signal");
  }
  
  /* Convert hex digit A to a number.  */
***************
*** 246,251 ****
--- 266,272 ----
        *p++ = tohex (regs[i] & 0xf);
      }
  
+   *p = '\0';
    remote_send (buf);
  }
  
***************
*** 312,317 ****
--- 333,339 ----
        *p++ = tohex (myaddr[i] & 0xf);
      }
  
+   *p = '\0';
    remote_send (buf);
  }
  
***************
*** 371,376 ****
--- 393,416 ----
  
  */
  
+ static int
+ readchar ()
+ {
+   char buf[1];
+ 
+   buf[0] = '\0';
+   alarm(timeout);
+   read (remote_desc, buf, 1);
+   alarm(0);
+ 
+ /*
+   if (kiodebug > 1)
+ 	printf("[readchar] got '%c' (0x%x)\n", buf[0] & 0x7f, buf[0] & 0x7f);
+ */
+ 
+   return buf[0] & 0x7f;
+ }
+ 
  /* Send the command in BUF to the remote machine,
     and read the reply into BUF.
     Report an error if we get an error reply.  */
***************
*** 401,409 ****
    int cnt = strlen (buf);
    char *p;
  
-   if (kiodebug)
-     fprintf (stderr, "Sending packet: %s\n", buf);
- 
    /* Copy the packet into buffer BUF2, encapsulating it
       and giving it a checksum.  */
  
--- 441,446 ----
***************
*** 422,440 ****
    /* Send it over and over until we get a positive ack.  */
  
    do {
      write (remote_desc, buf2, p - buf2);
!     read (remote_desc, buf3, 1);
!   } while (buf3[0] != '+');
  }
  
- static int
- readchar ()
- {
-   char buf[1];
-   while (read (remote_desc, buf, 1) != 1) ;
-   return buf[0] & 0x7f;
- }
- 
  /* Read a packet from the remote machine, with error checking,
     and store it in BUF.  */
  
--- 459,472 ----
    /* Send it over and over until we get a positive ack.  */
  
    do {
+     if (kiodebug) {
+ 	  *p = '\0';
+       fprintf (stderr, "Sending packet: %s (%s)\n", buf2, buf);
+     }
      write (remote_desc, buf2, p - buf2);
!   } while (readchar() != '+');
  }
  
  /* Read a packet from the remote machine, with error checking,
     and store it in BUF.  */
  
***************
*** 444,450 ****
  {
    char *bp;
    char csum = 0;
!   int c, c1, c2;
    extern kiodebug;
  
    while (1)
--- 476,483 ----
  {
    char *bp;
    char csum = 0;
!   int c;
!   unsigned char c1, c2;
    extern kiodebug;
  
    while (1)
***************
*** 452,457 ****
--- 485,491 ----
        while ((c = readchar()) != '$');
  
        bp = buf;
+ 	  csum = 0;
        while (1)
  	{
  	  c = readchar ();
***************
*** 464,473 ****
  
        c1 = fromhex (readchar ());
        c2 = fromhex (readchar ());
!       if (csum == (c1 << 4) + c2)
  	break;
        printf ("Bad checksum, sentsum=0x%x, csum=0x%x, buf=%s\n",
! 	      (c1 << 4) + c2, csum, buf);
        write (remote_desc, "-", 1);
      }
  
--- 498,508 ----
  
        c1 = fromhex (readchar ());
        c2 = fromhex (readchar ());
!       if ((csum & 0xff) == (c1 << 4) + c2)
  	break;
        printf ("Bad checksum, sentsum=0x%x, csum=0x%x, buf=%s\n",
! 	      (c1 << 4) + c2, csum & 0xff, buf);
! 
        write (remote_desc, "-", 1);
      }