1 /* Remote target communications for serial-line targets in custom GDB protocol
2 Copyright 1988, 1991, 1992, 1993 Free Software Foundation, Inc.
4 This file is part of GDB.
6 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2 of the License, or
9 (at your option) any later version.
11 This program is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with this program; if not, write to the Free Software
18 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */
20 /* Remote communication protocol.
22 A debug packet whose contents are <data>
23 is encapsulated for transmission in the form:
25 $ <data> # CSUM1 CSUM2
27 <data> must be ASCII alphanumeric and cannot include characters
30 CSUM1 and CSUM2 are ascii hex representation of an 8-bit
31 checksum of <data>, the most significant nibble is sent first.
32 the hex digits 0-9,a-f are used.
34 Receiver responds with:
36 + - if CSUM is correct and ready for next packet
37 - - if CSUM is incorrect
40 All values are encoded in ascii hex digits.
45 reply XX....X Each byte of register data
46 is described by two hex digits.
47 Registers are in the internal order
48 for GDB, and the bytes in a register
49 are in the same order the machine uses.
52 write regs GXX..XX Each byte of register data
53 is described by two hex digits.
57 read mem mAA..AA,LLLL AA..AA is address, LLLL is length.
58 reply XX..XX XX..XX is mem contents
59 Can be fewer bytes than requested
60 if able to read only part of the data.
63 write mem MAA..AA,LLLL:XX..XX
65 LLLL is number of bytes,
68 ENN for an error (this includes the case
69 where only part of the data was
72 cont cAA..AA AA..AA is address to resume
74 resume at same address.
76 step sAA..AA AA..AA is address to resume
78 resume at same address.
80 last signal ? Reply the current reason for stopping.
81 This is the same reply as is generated
82 for step or cont : SAA where AA is the
85 There is no immediate reply to step or cont.
86 The reply comes when the machine stops.
87 It is SAA AA is the "signal number"
89 or... TAAn...:r...;n:r...;n...:r...;
91 n... = register number
92 r... = register contents
96 toggle debug d toggle debug flag (see 386 & 68k stubs)
97 reset r reset -- see sparc stub.
98 reserved <other> On other requests, the stub should
99 ignore the request and send an empty
100 response ($#<checksum>). This way
101 we can extend the protocol and GDB
102 can tell whether the stub it is
103 talking to uses the old or the new.
110 #include "inferior.h"
115 #include "terminal.h"
120 #if !defined(DONT_USE_REMOTE)
122 #include <sys/types.h>
128 /* Prototypes for local functions */
131 remote_write_bytes
PARAMS ((CORE_ADDR memaddr
, unsigned char *myaddr
, int len
));
134 remote_read_bytes
PARAMS ((CORE_ADDR memaddr
, unsigned char *myaddr
, int len
));
137 remote_files_info
PARAMS ((struct target_ops
*ignore
));
140 remote_xfer_memory
PARAMS ((CORE_ADDR memaddr
, char *myaddr
, int len
,
141 int should_write
, struct target_ops
*target
));
144 remote_prepare_to_store
PARAMS ((void));
147 remote_fetch_registers
PARAMS ((int regno
));
150 remote_resume
PARAMS ((int pid
, int step
, int siggnal
));
153 remote_start_remote
PARAMS ((char *dummy
));
156 remote_open
PARAMS ((char *name
, int from_tty
));
159 remote_close
PARAMS ((int quitting
));
162 remote_store_registers
PARAMS ((int regno
));
165 getpkt
PARAMS ((char *buf
, int forever
));
168 putpkt
PARAMS ((char *buf
));
171 remote_send
PARAMS ((char *buf
));
174 readchar
PARAMS ((void));
177 remote_wait
PARAMS ((WAITTYPE
*status
));
180 tohex
PARAMS ((int nib
));
183 fromhex
PARAMS ((int a
));
186 remote_detach
PARAMS ((char *args
, int from_tty
));
189 remote_interrupt
PARAMS ((int signo
));
192 remote_interrupt_twice
PARAMS ((int signo
));
194 extern struct target_ops remote_ops
; /* Forward decl */
196 /* This was 5 seconds, which is a long time to sit and wait.
197 Unless this is going though some terminal server or multiplexer or
198 other form of hairy serial connection, I would think 2 seconds would
200 static int timeout
= 2;
206 /* Descriptor for I/O to remote machine. Initialize it to NULL so that
207 remote_open knows that we don't have a file open when the program
209 serial_t remote_desc
= NULL
;
213 /* Maximum number of bytes to read/write at once. The value here
214 is chosen to fill up a packet (the headers account for the 32). */
215 #define MAXBUFBYTES ((PBUFSIZ-32)/2)
217 /* Round up PBUFSIZ to hold all the registers, at least. */
218 #if REGISTER_BYTES > MAXBUFBYTES
220 #define PBUFSIZ (REGISTER_BYTES * 2 + 32)
223 /* Clean up connection to a remote debugger. */
227 remote_close (quitting
)
231 SERIAL_CLOSE (remote_desc
);
235 /* Stub for catch_errors. */
238 remote_start_remote (dummy
)
241 immediate_quit
= 1; /* Allow user to interrupt it */
243 /* Ack any packet which the remote side has already sent. */
244 /* I'm not sure this \r is needed; we don't use it any other time we
246 SERIAL_WRITE (remote_desc
, "+\r", 2);
247 putpkt ("?"); /* initiate a query from remote machine */
250 start_remote (); /* Initialize gdb process mechanisms */
254 /* Open a connection to a remote debugger.
255 NAME is the filename used for communication. */
257 static DCACHE
*remote_dcache
;
260 remote_open (name
, from_tty
)
266 "To open a remote debug connection, you need to specify what serial\n\
267 device is attached to the remote system (e.g. /dev/ttya).");
269 target_preopen (from_tty
);
271 unpush_target (&remote_ops
);
273 remote_dcache
= dcache_init (remote_read_bytes
, remote_write_bytes
);
275 remote_desc
= SERIAL_OPEN (name
);
277 perror_with_name (name
);
283 if (sscanf (baud_rate
, "%d", &rate
) == 1)
284 if (SERIAL_SETBAUDRATE (remote_desc
, rate
))
286 SERIAL_CLOSE (remote_desc
);
287 perror_with_name (name
);
291 SERIAL_RAW (remote_desc
);
295 puts_filtered ("Remote debugging using ");
296 puts_filtered (name
);
297 puts_filtered ("\n");
299 push_target (&remote_ops
); /* Switch to using remote target now */
301 /* Start the remote connection; if error (0), discard this target.
302 In particular, if the user quits, be sure to discard it
303 (we'd be in an inconsistent state otherwise). */
304 if (!catch_errors (remote_start_remote
, (char *)0,
305 "Couldn't establish connection to remote target\n", RETURN_MASK_ALL
))
310 takes a program previously attached to and detaches it.
311 We better not have left any breakpoints
312 in the program or it'll die when it hits one.
313 Close the open connection to the remote debugger.
314 Use this when you want to detach and do something else
318 remote_detach (args
, from_tty
)
323 error ("Argument given to \"detach\" when remotely debugging.");
327 puts_filtered ("Ending remote debugging.\n");
330 /* Convert hex digit A to a number. */
336 if (a
>= '0' && a
<= '9')
338 else if (a
>= 'a' && a
<= 'f')
341 error ("Reply contains invalid hex digit");
345 /* Convert number NIB to a hex digit. */
357 /* Tell the remote machine to resume. */
360 remote_resume (pid
, step
, siggnal
)
361 int pid
, step
, siggnal
;
368 target_terminal_ours_for_output ();
369 printf_filtered ("Can't send signals to a remote system. ");
370 name
= strsigno (siggnal
);
372 printf_filtered (name
);
374 printf_filtered ("Signal %d", siggnal
);
375 printf_filtered (" not sent.\n");
376 target_terminal_inferior ();
379 dcache_flush (remote_dcache
);
381 strcpy (buf
, step
? "s": "c");
386 /* Send ^C to target to halt it. Target will respond, and send us a
390 remote_interrupt (signo
)
393 /* If this doesn't work, try more severe steps. */
394 signal (signo
, remote_interrupt_twice
);
397 printf ("remote_interrupt called\n");
399 SERIAL_WRITE (remote_desc
, "\003", 1); /* Send a ^C */
402 static void (*ofunc
)();
404 /* The user typed ^C twice. */
406 remote_interrupt_twice (signo
)
409 signal (signo
, ofunc
);
411 target_terminal_ours ();
412 if (query ("Interrupted while waiting for the program.\n\
413 Give up (and stop debugging it)? "))
415 target_mourn_inferior ();
416 return_to_top_level (RETURN_QUIT
);
420 signal (signo
, remote_interrupt
);
421 target_terminal_inferior ();
425 /* Wait until the remote machine stops, then return,
426 storing status in STATUS just as `wait' would.
427 Returns "pid" (though it's not clear what, if anything, that
428 means in the case of this target). */
434 unsigned char buf
[PBUFSIZ
];
438 char regs
[MAX_REGISTER_RAW_SIZE
];
440 WSETEXIT ((*status
), 0);
442 ofunc
= (void (*)()) signal (SIGINT
, remote_interrupt
);
443 getpkt ((char *) buf
, 1);
444 signal (SIGINT
, ofunc
);
447 error ("Remote failure reply: %s", buf
);
450 /* Expedited reply, containing Signal, {regno, reg} repeat */
451 /* format is: 'Tssn...:r...;n...:r...;n...:r...;#cc', where
453 n... = register number
454 r... = register contents
457 p
= &buf
[3]; /* after Txx */
463 regno
= strtol (p
, &p1
, 16); /* Read the register number */
466 error ("Remote sent badly formed register number: %s\nPacket: '%s'\n",
472 error ("Malformed packet (missing colon): %s\nPacket: '%s'\n",
475 if (regno
>= NUM_REGS
)
476 error ("Remote sent bad register number %d: %s\nPacket: '%s'\n",
479 for (i
= 0; i
< REGISTER_RAW_SIZE (regno
); i
++)
481 if (p
[0] == 0 || p
[1] == 0)
482 error ("Remote reply is too short: %s", buf
);
483 regs
[i
] = fromhex (p
[0]) * 16 + fromhex (p
[1]);
488 error("Remote register badly formatted: %s", buf
);
490 supply_register (regno
, regs
);
493 else if (buf
[0] != 'S')
494 error ("Invalid remote reply: %s", buf
);
496 WSETSTOP ((*status
), (((fromhex (buf
[1])) << 4) + (fromhex (buf
[2]))));
501 /* Read the remote registers into the block REGS. */
502 /* Currently we just read all the registers, so we don't use regno. */
505 remote_fetch_registers (regno
)
511 char regs
[REGISTER_BYTES
];
516 /* Reply describes registers byte by byte, each byte encoded as two
517 hex characters. Suck them all up, then supply them to the
518 register cacheing/storage mechanism. */
521 for (i
= 0; i
< REGISTER_BYTES
; i
++)
523 if (p
[0] == 0 || p
[1] == 0)
524 error ("Remote reply is too short: %s", buf
);
525 regs
[i
] = fromhex (p
[0]) * 16 + fromhex (p
[1]);
528 for (i
= 0; i
< NUM_REGS
; i
++)
529 supply_register (i
, ®s
[REGISTER_BYTE(i
)]);
532 /* Prepare to store registers. Since we send them all, we have to
533 read out the ones we don't want to change first. */
536 remote_prepare_to_store ()
538 /* Make sure the entire registers array is valid. */
539 read_register_bytes (0, (char *)NULL
, REGISTER_BYTES
);
542 /* Store the remote registers from the contents of the block REGISTERS.
543 FIXME, eventually just store one register if that's all that is needed. */
547 remote_store_registers (regno
)
556 /* Command describes registers byte by byte,
557 each byte encoded as two hex characters. */
560 for (i
= 0; i
< REGISTER_BYTES
; i
++)
562 *p
++ = tohex ((registers
[i
] >> 4) & 0xf);
563 *p
++ = tohex (registers
[i
] & 0xf);
572 /* Use of the data cache is disabled because it loses for looking at
573 and changing hardware I/O ports and the like. Accepting `volatile'
574 would perhaps be one way to fix it, but a better way which would
575 win for more cases would be to use the executable file for the text
576 segment, like the `icache' code below but done cleanly (in some
577 target-independent place, perhaps in target_xfer_memory, perhaps
578 based on assigning each target a speed or perhaps by some simpler
581 /* Read a word from remote address ADDR and return it.
582 This goes through the data cache. */
585 remote_fetch_word (addr
)
591 extern CORE_ADDR text_start
, text_end
;
593 if (addr
>= text_start
&& addr
< text_end
)
596 xfer_core_file (addr
, &buffer
, sizeof (int));
601 return dcache_fetch (remote_dcache
, addr
);
604 /* Write a word WORD into remote address ADDR.
605 This goes through the data cache. */
608 remote_store_word (addr
, word
)
612 dcache_poke (remote_dcache
, addr
, word
);
616 /* Write memory data directly to the remote machine.
617 This does not inform the data cache; the data cache uses this.
618 MEMADDR is the address in the remote memory space.
619 MYADDR is the address of the buffer in our space.
620 LEN is the number of bytes.
622 Returns number of bytes transferred, or 0 for error. */
625 remote_write_bytes (memaddr
, myaddr
, len
)
627 unsigned char *myaddr
;
634 if (len
> PBUFSIZ
/ 2 - 20)
637 sprintf (buf
, "M%x,%x:", memaddr
, len
);
639 /* We send target system values byte by byte, in increasing byte addresses,
640 each byte encoded as two hex characters. */
642 p
= buf
+ strlen (buf
);
643 for (i
= 0; i
< len
; i
++)
645 *p
++ = tohex ((myaddr
[i
] >> 4) & 0xf);
646 *p
++ = tohex (myaddr
[i
] & 0xf);
655 /* There is no correspondance between what the remote protocol uses
656 for errors and errno codes. We would like a cleaner way of
657 representing errors (big enough to include errno codes, bfd_error
658 codes, and others). But for now just return EIO. */
665 /* Read memory data directly from the remote machine.
666 This does not use the data cache; the data cache uses this.
667 MEMADDR is the address in the remote memory space.
668 MYADDR is the address of the buffer in our space.
669 LEN is the number of bytes.
671 Returns number of bytes transferred, or 0 for error. */
674 remote_read_bytes (memaddr
, myaddr
, len
)
676 unsigned char *myaddr
;
683 if (len
> PBUFSIZ
/ 2 - 1)
686 sprintf (buf
, "m%x,%x", memaddr
, len
);
692 /* There is no correspondance between what the remote protocol uses
693 for errors and errno codes. We would like a cleaner way of
694 representing errors (big enough to include errno codes, bfd_error
695 codes, and others). But for now just return EIO. */
700 /* Reply describes memory byte by byte,
701 each byte encoded as two hex characters. */
704 for (i
= 0; i
< len
; i
++)
706 if (p
[0] == 0 || p
[1] == 0)
707 /* Reply is short. This means that we were able to read only part
708 of what we wanted to. */
710 myaddr
[i
] = fromhex (p
[0]) * 16 + fromhex (p
[1]);
716 /* Read or write LEN bytes from inferior memory at MEMADDR, transferring
717 to or from debugger address MYADDR. Write to inferior if SHOULD_WRITE is
718 nonzero. Returns length of data written or read; 0 for error. */
722 remote_xfer_memory(memaddr
, myaddr
, len
, should_write
, target
)
727 struct target_ops
*target
; /* ignored */
731 int total_xferred
= 0;
735 if (len
> MAXBUFBYTES
)
736 xfersize
= MAXBUFBYTES
;
741 bytes_xferred
= remote_write_bytes (memaddr
, myaddr
, xfersize
);
743 bytes_xferred
= remote_read_bytes (memaddr
, myaddr
, xfersize
);
745 /* If we get an error, we are done xferring. */
746 if (bytes_xferred
== 0)
749 memaddr
+= bytes_xferred
;
750 myaddr
+= bytes_xferred
;
751 len
-= bytes_xferred
;
752 total_xferred
+= bytes_xferred
;
754 return total_xferred
;
758 remote_files_info (ignore
)
759 struct target_ops
*ignore
;
761 puts_filtered ("Debugging a target over a serial line.\n");
764 /* Stuff for dealing with the packets which are part of this protocol.
765 See comment at top of file for details. */
767 /* Read a single character from the remote end, masking it down to 7 bits. */
774 ch
= SERIAL_READCHAR (remote_desc
, timeout
);
782 /* Send the command in BUF to the remote machine,
783 and read the reply into BUF.
784 Report an error if we get an error reply. */
795 error ("Remote failure reply: %s", buf
);
798 /* Send a packet to the remote machine, with error checking.
799 The data of the packet is in BUF. */
806 unsigned char csum
= 0;
808 int cnt
= strlen (buf
);
812 /* Copy the packet into buffer BUF2, encapsulating it
813 and giving it a checksum. */
815 if (cnt
> sizeof(buf2
) - 5) /* Prosanity check */
821 for (i
= 0; i
< cnt
; i
++)
827 *p
++ = tohex ((csum
>> 4) & 0xf);
828 *p
++ = tohex (csum
& 0xf);
830 /* Send it over and over until we get a positive ack. */
837 printf ("Sending packet: %s...", buf2
); fflush(stdout
);
839 if (SERIAL_WRITE (remote_desc
, buf2
, p
- buf2
))
840 perror_with_name ("putpkt: write failed");
842 /* read until either a timeout occurs (-2) or '+' is read */
854 break; /* Retransmit buffer */
856 perror_with_name ("putpkt: couldn't read ACK");
858 error ("putpkt: EOF while trying to read ACK");
861 printf ("%02X %c ", ch
&0xFF, ch
);
864 break; /* Here to retransmit */
869 /* Read a packet from the remote machine, with error checking,
870 and store it in BUF. BUF is expected to be of size PBUFSIZ.
871 If FOREVER, wait forever rather than timing out; this is used
872 while the target is executing user code. */
875 getpkt (buf
, forever
)
882 unsigned char c1
, c2
;
884 #define MAX_RETRIES 10
888 /* This can loop forever if the remote side sends us characters
889 continuously, but if it pauses, we'll get a zero from readchar
890 because of timeout. Then we'll count that as a retry. */
893 if (c
> 0 && c
!= '$')
896 if (c
== SERIAL_TIMEOUT
)
900 if (++retries
>= MAX_RETRIES
)
901 if (remote_debug
) puts_filtered ("Timed out.\n");
906 error ("Remote connection closed");
907 if (c
== SERIAL_ERROR
)
908 perror_with_name ("Remote communication error");
910 /* Force csum to be zero here because of possible error retry. */
917 if (c
== SERIAL_TIMEOUT
)
920 puts_filtered ("Timeout in mid-packet, retrying\n");
921 goto whole
; /* Start a new packet, count retries */
926 puts_filtered ("Saw new packet start in middle of old one\n");
927 goto whole
; /* Start a new packet, count retries */
931 if (bp
>= buf
+PBUFSIZ
-1)
934 puts_filtered ("Remote packet too long: ");
936 puts_filtered ("\n");
944 c1
= fromhex (readchar ());
945 c2
= fromhex (readchar ());
946 if ((csum
& 0xff) == (c1
<< 4) + c2
)
948 printf_filtered ("Bad checksum, sentsum=0x%x, csum=0x%x, buf=",
949 (c1
<< 4) + c2
, csum
& 0xff);
951 puts_filtered ("\n");
953 /* Try the whole thing again. */
955 if (++retries
< MAX_RETRIES
)
957 SERIAL_WRITE (remote_desc
, "-", 1);
961 printf ("Ignoring packet error, continuing...\n");
968 SERIAL_WRITE (remote_desc
, "+", 1);
971 fprintf (stderr
,"Packet received: %s\n", buf
);
978 /* Don't wait for it to die. I'm not really sure it matters whether
979 we do or not. For the existing stubs, kill is a noop. */
980 target_mourn_inferior ();
986 unpush_target (&remote_ops
);
987 generic_mourn_inferior ();
990 #ifdef REMOTE_BREAKPOINT
992 /* On some machines, e.g. 68k, we may use a different breakpoint instruction
993 than other targets. */
994 static unsigned char break_insn
[] = REMOTE_BREAKPOINT
;
996 /* Check that it fits in BREAKPOINT_MAX bytes. */
997 static unsigned char check_break_insn_size
[BREAKPOINT_MAX
] = REMOTE_BREAKPOINT
;
999 #else /* No REMOTE_BREAKPOINT. */
1001 /* Same old breakpoint instruction. This code does nothing different
1002 than mem-break.c. */
1003 static unsigned char break_insn
[] = BREAKPOINT
;
1005 #endif /* No REMOTE_BREAKPOINT. */
1007 /* Insert a breakpoint on targets that don't have any better breakpoint
1008 support. We read the contents of the target location and stash it,
1009 then overwrite it with a breakpoint instruction. ADDR is the target
1010 location in the target machine. CONTENTS_CACHE is a pointer to
1011 memory allocated for saving the target contents. It is guaranteed
1012 by the caller to be long enough to save sizeof BREAKPOINT bytes (this
1013 is accomplished via BREAKPOINT_MAX). */
1016 remote_insert_breakpoint (addr
, contents_cache
)
1018 char *contents_cache
;
1022 val
= target_read_memory (addr
, contents_cache
, sizeof break_insn
);
1025 val
= target_write_memory (addr
, (char *)break_insn
, sizeof break_insn
);
1031 remote_remove_breakpoint (addr
, contents_cache
)
1033 char *contents_cache
;
1035 return target_write_memory (addr
, contents_cache
, sizeof break_insn
);
1038 /* Define the target subroutine names */
1040 struct target_ops remote_ops
= {
1041 "remote", /* to_shortname */
1042 "Remote serial target in gdb-specific protocol", /* to_longname */
1043 "Use a remote computer via a serial line, using a gdb-specific protocol.\n\
1044 Specify the serial device it is connected to (e.g. /dev/ttya).", /* to_doc */
1045 remote_open
, /* to_open */
1046 remote_close
, /* to_close */
1047 NULL
, /* to_attach */
1048 remote_detach
, /* to_detach */
1049 remote_resume
, /* to_resume */
1050 remote_wait
, /* to_wait */
1051 remote_fetch_registers
, /* to_fetch_registers */
1052 remote_store_registers
, /* to_store_registers */
1053 remote_prepare_to_store
, /* to_prepare_to_store */
1054 remote_xfer_memory
, /* to_xfer_memory */
1055 remote_files_info
, /* to_files_info */
1057 remote_insert_breakpoint
, /* to_insert_breakpoint */
1058 remote_remove_breakpoint
, /* to_remove_breakpoint */
1060 NULL
, /* to_terminal_init */
1061 NULL
, /* to_terminal_inferior */
1062 NULL
, /* to_terminal_ours_for_output */
1063 NULL
, /* to_terminal_ours */
1064 NULL
, /* to_terminal_info */
1065 remote_kill
, /* to_kill */
1066 generic_load
, /* to_load */
1067 NULL
, /* to_lookup_symbol */
1068 NULL
, /* to_create_inferior */
1069 remote_mourn
, /* to_mourn_inferior */
1071 0, /* to_notice_signals */
1072 process_stratum
, /* to_stratum */
1074 1, /* to_has_all_memory */
1075 1, /* to_has_memory */
1076 1, /* to_has_stack */
1077 1, /* to_has_registers */
1078 1, /* to_has_execution */
1079 NULL
, /* sections */
1080 NULL
, /* sections_end */
1081 OPS_MAGIC
/* to_magic */
1085 _initialize_remote ()
1087 add_target (&remote_ops
);
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