[PATCH] Add support for qCRC packet

[Kevin Buettner <kevinb at redhat dot com>]

I've just committed the patch below.  It adds support for the qCRC
packet.  GDB uses this packet to implement the "compare-sections"
command which may be used to verify the results of a "load" command
or, on Linux, to see if the executable being debugged on the RDA side
is the same as that on the GDB side.

Kevin

	* lib/crc32.h, lib/crc32.c: New files.
	* lib/Makefile.am (librda_la_SOURCES): Add crc32.c to list.
	* lib/Makefile.in: Regenerate.
	* lib/gdbserv-state.c (crc32.h): Include.
	(read_memory, do_qCRC_packet): New functions.
	(gdbserv_data_packet): Add support for qCRC packet.

Index: lib/Makefile.am
===================================================================
RCS file: /cvs/src/src/rda/lib/Makefile.am,v
retrieving revision 1.2
diff -u -p -r1.2 Makefile.am
--- lib/Makefile.am	8 Feb 2005 05:01:16 -0000	1.2
+++ lib/Makefile.am	3 Mar 2005 19:36:25 -0000
@@ -24,4 +24,5 @@ librda_la_SOURCES =				\
 	gdbserv-log.c				\
 	gdbloop.c				\
 	gdbsched.c				\
-	gdbserv-target.c
+	gdbserv-target.c			\
+	crc32.c
Index: lib/crc32.c
===================================================================
RCS file: lib/crc32.c
diff -N lib/crc32.c
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ lib/crc32.c	3 Mar 2005 19:36:25 -0000
@@ -0,0 +1,121 @@
+/* crc32.c
+
+   Copyright 2005 Red Hat, Inc.
+
+   This file is part of RDA, the Red Hat Debug Agent (and library).
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.
+   
+   Alternative licenses for RDA may be arranged by contacting Red Hat,
+   Inc.  */
+
+#include "crc32.h"
+
+static long crc32_table[] = 
+{
+  0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9,
+  0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005,
+  0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61,
+  0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd,
+  0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9,
+  0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75,
+  0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011,
+  0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd,
+  0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039,
+  0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5,
+  0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81,
+  0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d,
+  0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49,
+  0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95,
+  0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1,
+  0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d,
+  0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae,
+  0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072,
+  0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16,
+  0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca,
+  0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde,
+  0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02,
+  0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066,
+  0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba,
+  0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e,
+  0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692,
+  0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6,
+  0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a,
+  0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e,
+  0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2,
+  0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686,
+  0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a,
+  0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637,
+  0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb,
+  0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f,
+  0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53,
+  0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47,
+  0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b,
+  0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff,
+  0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623,
+  0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7,
+  0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b,
+  0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f,
+  0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3,
+  0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7,
+  0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b,
+  0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f,
+  0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3,
+  0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640,
+  0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c,
+  0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8,
+  0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24,
+  0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30,
+  0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec,
+  0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088,
+  0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654,
+  0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0,
+  0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c,
+  0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18,
+  0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4,
+  0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0,
+  0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c,
+  0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668,
+  0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4
+};
+
+/* crc32(), below, is based on crc_normal() from
+   ftp://ftp.rocksoft.com/papers/crc_v3.txt.  The C code contained
+   in that document is fully in the public domain.
+   
+   INIT (from the above site) is passed in as ``crc''.  It starts out
+   as 0xffffffff (which is a common value to use) to match GDB.  We
+   pass this value as a parameter so that crc32() may be used iteratively
+   over a number of blocks.  This is accomplished by passing 0xffffffff
+   as ``crc'' for the first block and then passing the output of crc32()
+   for the previous block as ``crc'' for all subsequent blocks.
+   
+   XOROT is 0.  This is atypical for crc implementations; 0xffffffff is
+   more commonly used.  This value was chosen so as to match GDB.  This
+   is a convenient value to use because it allows the function below to
+   be called iteratively (as described above) using the previous block's
+   crc32() output without modification.
+   
+   The polynomial constant used to create the lookup table is
+   0x04c11db7 which, again, matches GDB.  */
+
+unsigned long
+crc32 (unsigned char *blk, int blk_len, unsigned long crc)
+{
+  while (blk_len--)
+    crc = crc32_table[((crc >> 24) ^ *blk++) & 0xffL] ^ (crc << 8);
+  return crc;
+}
Index: lib/crc32.h
===================================================================
RCS file: lib/crc32.h
diff -N lib/crc32.h
--- /dev/null	1 Jan 1970 00:00:00 -0000
+++ lib/crc32.h	3 Mar 2005 19:36:25 -0000
@@ -0,0 +1,43 @@
+/* crc32.h
+
+   Copyright 2005 Red Hat, Inc.
+
+   This file is part of RDA, the Red Hat Debug Agent (and library).
+
+   This program is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2 of the License, or
+   (at your option) any later version.
+
+   This program is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+   GNU General Public License for more details.
+
+   You should have received a copy of the GNU General Public License
+   along with this program; if not, write to the Free Software
+   Foundation, Inc., 59 Temple Place - Suite 330,
+   Boston, MA 02111-1307, USA.
+   
+   Alternative licenses for RDA may be arranged by contacting Red Hat,
+   Inc.  */
+
+/* crc32() computes a 32-bit CRC.
+
+   In order to match GDB, the initial value for ``crc'' must be 0xffffffff.
+   When using this function iteratively over a number of blocks, the
+   previous block's crc32() value should be used for the ``crc'' parameter
+   on the second and subsequent blocks.   The code might be structured
+   as follows:
+
+     char blk[1024];
+     int size;
+     unsigned long crc = 0xffffffff;
+
+     do {
+       size = read_a_block (blk, sizeof (blk));
+       crc = crc32 (blk, size, crc);
+     } while (size > 0);
+*/
+
+unsigned long crc32 (unsigned char *blk, int blk_len, unsigned long crc);
Index: lib/gdbserv-state.c
===================================================================
RCS file: /cvs/src/src/rda/lib/gdbserv-state.c,v
retrieving revision 1.4
diff -u -p -r1.4 gdbserv-state.c
--- lib/gdbserv-state.c	8 Oct 2004 05:02:26 -0000	1.4
+++ lib/gdbserv-state.c	3 Mar 2005 19:36:26 -0000
@@ -32,6 +32,7 @@
 #include "gdbserv-utils.h"
 #include "gdblog.h"
 #include "gdbserv-log.h"
+#include "crc32.h"
 
 static int output_thread_reg (struct gdbserv *gdbserv,
 			      struct gdbserv_thread *thread,
@@ -621,6 +622,77 @@ do_get_registers_p_packet (struct gdbser
     }
 }
 
+static long
+read_memory (struct gdbserv *gdbserv, struct gdbserv_reg *addr_p, void *block,
+             long len)
+{
+  long nr_read;
+  if (gdbserv->target->get_thread_mem != NULL)
+    nr_read = 
+      gdbserv->target->get_thread_mem (gdbserv, 
+				       gdbserv->general_thread,
+				       addr_p, block, len);
+  else if (gdbserv->target->get_mem != NULL)
+    nr_read = gdbserv->target->get_mem (gdbserv, addr_p, block, len);
+  else
+    assert (0);
+  return nr_read;
+}
+
+static void
+do_qCRC_packet (struct gdbserv *gdbserv)
+{
+  struct gdbserv_reg addr;
+  long len;
+  unsigned long crc = 0xffffffff;	/* See crc32.h.  */
+  struct gdbserv_reg crc_reg;
+
+  /* Fetch addr,length.  */
+  if (gdbserv_input_reg_beb (gdbserv, &addr, 0) < 0)
+    {
+      gdbserv_output_string (gdbserv, "E01");
+    }
+  else if (gdbserv_input_char (gdbserv) != ',')
+    {
+      gdbserv_output_string (gdbserv, "E02");
+    }
+  else if (gdbserv_input_hex_ulong (gdbserv, &len) < 0)
+    {
+      gdbserv_output_string (gdbserv, "E03");
+    }
+
+  while (len > 0)
+    {
+      char buf[1024];
+      unsigned long long addr_ull;
+      int size = sizeof (buf) < len ? sizeof (buf) : len;
+
+      /* Read a block.  Quit early if the read doesn't succeed.  */
+      size = read_memory (gdbserv, &addr, buf, size);
+      if (size <= 0)
+	{
+	  gdbserv_output_string (gdbserv, "E07");
+	  return;
+	}
+
+      /* Compute the accumlated CRC.  */
+      crc = crc32 (buf, size, crc);
+
+      /* Advance ``addr'' by ``size''.  */
+      gdbserv_reg_to_ulonglong (gdbserv, &addr, &addr_ull);
+      addr_ull += size;
+      gdbserv_ulonglong_to_reg (gdbserv, addr_ull, &addr);
+
+      /* Adjust the length based on amount actually read.  */
+      len -= size;
+    }
+
+  /* Output the CRC in the format expected by GDB.  */
+  gdbserv_output_char (gdbserv, 'C');
+  gdbserv_ulong_to_reg (gdbserv, crc, &crc_reg);
+  gdbserv_output_reg_beb (gdbserv, &crc_reg, 0);
+}
+
 void
 gdbserv_data_packet (struct gdbserv *gdbserv)
 {
@@ -686,6 +758,10 @@ gdbserv_data_packet (struct gdbserv *gdb
 	      gdbserv->target->process_rcmd (gdbserv, cmd, sizeof_cmd);
 	    }
 	}
+      else if (gdbserv_input_string_match (gdbserv, "CRC:") >= 0)
+	{
+	  do_qCRC_packet (gdbserv);
+	}
       else if (gdbserv_input_string_match (gdbserv, "C") >= 0)
 	{
 	  do_current_thread_query (gdbserv);