gdb/gdbserver/mem-break.c

   1 /* Memory breakpoint operations for the remote server for GDB.
   2    Copyright (C) 2002, 2003, 2005, 2007 Free Software Foundation, Inc.
   3
   4    Contributed by MontaVista Software.
   5
   6    This file is part of GDB.
   7
   8    This program is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2 of the License, or
  11    (at your option) any later version.
  12
  13    This program is distributed in the hope that it will be useful,
  14    but WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16    GNU General Public License for more details.
  17
  18    You should have received a copy of the GNU General Public License
  19    along with this program; if not, write to the Free Software
  20    Foundation, Inc., 51 Franklin Street, Fifth Floor,
  21    Boston, MA 02110-1301, USA.  */
  22
  23 #include "server.h"
  24
  25 const unsigned char *breakpoint_data;
  26 int breakpoint_len;
  27
  28 #define MAX_BREAKPOINT_LEN 8
  29
  30 struct breakpoint
  31 {
  32   struct breakpoint *next;
  33   CORE_ADDR pc;
  34   unsigned char old_data[MAX_BREAKPOINT_LEN];
  35
  36   /* Non-zero iff we are stepping over this breakpoint.  */
  37   int reinserting;
  38
  39   /* Non-NULL iff this breakpoint was inserted to step over
  40      another one.  Points to the other breakpoint (which is also
  41      in the *next chain somewhere).  */
  42   struct breakpoint *breakpoint_to_reinsert;
  43
  44   /* Function to call when we hit this breakpoint.  */
  45   void (*handler) (CORE_ADDR);
  46 };
  47
  48 struct breakpoint *breakpoints;
  49
  50 void
  51 set_breakpoint_at (CORE_ADDR where, void (*handler) (CORE_ADDR))
  52 {
  53   struct breakpoint *bp;
  54
  55   if (breakpoint_data == NULL)
  56     error ("Target does not support breakpoints.");
  57
  58   bp = malloc (sizeof (struct breakpoint));
  59   memset (bp, 0, sizeof (struct breakpoint));
  60
  61   (*the_target->read_memory) (where, bp->old_data,
  62                               breakpoint_len);
  63   (*the_target->write_memory) (where, breakpoint_data,
  64                                breakpoint_len);
  65
  66   bp->pc = where;
  67   bp->handler = handler;
  68
  69   bp->next = breakpoints;
  70   breakpoints = bp;
  71 }
  72
  73 static void
  74 delete_breakpoint (struct breakpoint *bp)
  75 {
  76   struct breakpoint *cur;
  77
  78   if (breakpoints == bp)
  79     {
  80       breakpoints = bp->next;
  81       (*the_target->write_memory) (bp->pc, bp->old_data,
  82                                    breakpoint_len);
  83       free (bp);
  84       return;
  85     }
  86   cur = breakpoints;
  87   while (cur->next)
  88     {
  89       if (cur->next == bp)
  90         {
  91           cur->next = bp->next;
  92           (*the_target->write_memory) (bp->pc, bp->old_data,
  93                                        breakpoint_len);
  94           free (bp);
  95           return;
  96         }
  97     }
  98   warning ("Could not find breakpoint in list.");
  99 }
 100
 101 static struct breakpoint *
 102 find_breakpoint_at (CORE_ADDR where)
 103 {
 104   struct breakpoint *bp = breakpoints;
 105
 106   while (bp != NULL)
 107     {
 108       if (bp->pc == where)
 109         return bp;
 110       bp = bp->next;
 111     }
 112
 113   return NULL;
 114 }
 115
 116 static void
 117 reinsert_breakpoint_handler (CORE_ADDR stop_pc)
 118 {
 119   struct breakpoint *stop_bp, *orig_bp;
 120
 121   stop_bp = find_breakpoint_at (stop_pc);
 122   if (stop_bp == NULL)
 123     error ("lost the stopping breakpoint.");
 124
 125   orig_bp = stop_bp->breakpoint_to_reinsert;
 126   if (orig_bp == NULL)
 127     error ("no breakpoint to reinsert");
 128
 129   (*the_target->write_memory) (orig_bp->pc, breakpoint_data,
 130                                breakpoint_len);
 131   orig_bp->reinserting = 0;
 132   delete_breakpoint (stop_bp);
 133 }
 134
 135 void
 136 reinsert_breakpoint_by_bp (CORE_ADDR stop_pc, CORE_ADDR stop_at)
 137 {
 138   struct breakpoint *bp, *orig_bp;
 139
 140   set_breakpoint_at (stop_at, reinsert_breakpoint_handler);
 141
 142   orig_bp = find_breakpoint_at (stop_pc);
 143   if (orig_bp == NULL)
 144     error ("Could not find original breakpoint in list.");
 145
 146   bp = find_breakpoint_at (stop_at);
 147   if (bp == NULL)
 148     error ("Could not find breakpoint in list (reinserting by breakpoint).");
 149   bp->breakpoint_to_reinsert = orig_bp;
 150
 151   (*the_target->write_memory) (orig_bp->pc, orig_bp->old_data,
 152                                breakpoint_len);
 153   orig_bp->reinserting = 1;
 154 }
 155
 156 void
 157 uninsert_breakpoint (CORE_ADDR stopped_at)
 158 {
 159   struct breakpoint *bp;
 160
 161   bp = find_breakpoint_at (stopped_at);
 162   if (bp == NULL)
 163     error ("Could not find breakpoint in list (uninserting).");
 164
 165   (*the_target->write_memory) (bp->pc, bp->old_data,
 166                                breakpoint_len);
 167   bp->reinserting = 1;
 168 }
 169
 170 void
 171 reinsert_breakpoint (CORE_ADDR stopped_at)
 172 {
 173   struct breakpoint *bp;
 174
 175   bp = find_breakpoint_at (stopped_at);
 176   if (bp == NULL)
 177     error ("Could not find breakpoint in list (uninserting).");
 178   if (! bp->reinserting)
 179     error ("Breakpoint already inserted at reinsert time.");
 180
 181   (*the_target->write_memory) (bp->pc, breakpoint_data,
 182                                breakpoint_len);
 183   bp->reinserting = 0;
 184 }
 185
 186 int
 187 check_breakpoints (CORE_ADDR stop_pc)
 188 {
 189   struct breakpoint *bp;
 190
 191   bp = find_breakpoint_at (stop_pc);
 192   if (bp == NULL)
 193     return 0;
 194   if (bp->reinserting)
 195     {
 196       warning ("Hit a removed breakpoint?");
 197       return 0;
 198     }
 199
 200   (*bp->handler) (bp->pc);
 201   return 1;
 202 }
 203
 204 void
 205 set_breakpoint_data (const unsigned char *bp_data, int bp_len)
 206 {
 207   breakpoint_data = bp_data;
 208   breakpoint_len = bp_len;
 209 }
 210
 211 void
 212 check_mem_read (CORE_ADDR mem_addr, unsigned char *buf, int mem_len)
 213 {
 214   struct breakpoint *bp = breakpoints;
 215   CORE_ADDR mem_end = mem_addr + mem_len;
 216
 217   for (; bp != NULL; bp = bp->next)
 218     {
 219       CORE_ADDR bp_end = bp->pc + breakpoint_len;
 220       CORE_ADDR start, end;
 221       int copy_offset, copy_len, buf_offset;
 222
 223       if (mem_addr >= bp_end)
 224         continue;
 225       if (bp->pc >= mem_end)
 226         continue;
 227
 228       start = bp->pc;
 229       if (mem_addr > start)
 230         start = mem_addr;
 231
 232       end = bp_end;
 233       if (end > mem_end)
 234         end = mem_end;
 235
 236       copy_len = end - start;
 237       copy_offset = start - bp->pc;
 238       buf_offset = start - mem_addr;
 239
 240       memcpy (buf + buf_offset, bp->old_data + copy_offset, copy_len);
 241     }
 242 }
 243
 244 void
 245 check_mem_write (CORE_ADDR mem_addr, unsigned char *buf, int mem_len)
 246 {
 247   struct breakpoint *bp = breakpoints;
 248   CORE_ADDR mem_end = mem_addr + mem_len;
 249
 250   for (; bp != NULL; bp = bp->next)
 251     {
 252       CORE_ADDR bp_end = bp->pc + breakpoint_len;
 253       CORE_ADDR start, end;
 254       int copy_offset, copy_len, buf_offset;
 255
 256       if (mem_addr >= bp_end)
 257         continue;
 258       if (bp->pc >= mem_end)
 259         continue;
 260
 261       start = bp->pc;
 262       if (mem_addr > start)
 263         start = mem_addr;
 264
 265       end = bp_end;
 266       if (end > mem_end)
 267         end = mem_end;
 268
 269       copy_len = end - start;
 270       copy_offset = start - bp->pc;
 271       buf_offset = start - mem_addr;
 272
 273       memcpy (bp->old_data + copy_offset, buf + buf_offset, copy_len);
 274       if (bp->reinserting == 0)
 275         memcpy (buf + buf_offset, breakpoint_data + copy_offset, copy_len);
 276     }
 277 }