contrib/gdb-6.2.1/gdb/bsd-kvm.c

   1 /* BSD Kernel Data Access Library (libkvm) interface.
   2
   3    Copyright 2004 Free Software Foundation, Inc.
   4
   5    This file is part of GDB.
   6
   7    This program is free software; you can redistribute it and/or modify
   8    it under the terms of the GNU General Public License as published by
   9    the Free Software Foundation; either version 2 of the License, or
  10    (at your option) any later version.
  11
  12    This program is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15    GNU General Public License for more details.
  16
  17    You should have received a copy of the GNU General Public License
  18    along with this program; if not, write to the Free Software
  19    Foundation, Inc., 59 Temple Place - Suite 330,
  20    Boston, MA 02111-1307, USA.  */
  21
  22 #include "defs.h"
  23 #include "cli/cli-cmds.h"
  24 #include "command.h"
  25 #include "frame.h"
  26 #include "regcache.h"
  27 #include "target.h"
  28 #include "value.h"
  29
  30 #include "gdb_assert.h"
  31 #include <fcntl.h>
  32 #include <kvm.h>
  33 #include <nlist.h>
  34 #include "readline/readline.h"
  35 #include <sys/param.h>
  36 #include <sys/user.h>
  37
  38 #include "bsd-kvm.h"
  39
  40 /* Kernel memory interface descriptor.  */
  41 kvm_t *core_kd;
  42
  43 /* Address of process control block.  */
  44 struct pcb *bsd_kvm_paddr;
  45
  46 /* Pointer to architecture-specific function that reconstructs the
  47    register state from PCB and supplies it to REGCACHE.  */
  48 int (*bsd_kvm_supply_pcb)(struct regcache *regcache, struct pcb *pcb);
  49
  50 /* Target ops for libkvm interface.  */
  51 struct target_ops bsd_kvm_ops;
  52
  53 static void
  54 bsd_kvm_open (char *filename, int from_tty)
  55 {
  56   char errbuf[_POSIX2_LINE_MAX];
  57   char *execfile = NULL;
  58   kvm_t *temp_kd;
  59
  60   target_preopen (from_tty);
  61
  62   if (filename)
  63     {
  64       char *temp;
  65
  66       filename = tilde_expand (filename);
  67       if (filename[0] != '/')
  68         {
  69           temp = concat (current_directory, "/", filename, NULL);
  70           xfree (filename);
  71           filename = temp;
  72         }
  73     }
  74
  75   temp_kd = kvm_openfiles (execfile, filename, NULL, O_RDONLY, errbuf);
  76   if (temp_kd == NULL)
  77     error ("%s", errbuf);
  78
  79   unpush_target (&bsd_kvm_ops);
  80   core_kd = temp_kd;
  81   push_target (&bsd_kvm_ops);
  82
  83   target_fetch_registers (-1);
  84
  85   flush_cached_frames ();
  86   select_frame (get_current_frame ());
  87   print_stack_frame (get_selected_frame (), -1, 1);
  88 }
  89
  90 static void
  91 bsd_kvm_close (int quitting)
  92 {
  93   if (core_kd)
  94     {
  95       if (kvm_close (core_kd) == -1)
  96         warning ("%s", kvm_geterr(core_kd));
  97       core_kd = NULL;
  98     }
  99 }
 100
 101 static int
 102 bsd_kvm_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len,
 103                     int write, struct mem_attrib *attrib,
 104                     struct target_ops *ops)
 105 {
 106   if (write)
 107     return kvm_write (core_kd, memaddr, myaddr, len);
 108   else
 109     return kvm_read (core_kd, memaddr, myaddr, len);
 110
 111   return -1;
 112 }
 113
 114 /* Fetch process control block at address PADDR.  */
 115
 116 static int
 117 bsd_kvm_fetch_pcb (struct pcb *paddr)
 118 {
 119   struct pcb pcb;
 120
 121   if (kvm_read (core_kd, (unsigned long) paddr, &pcb, sizeof pcb) == -1)
 122     error ("%s", kvm_geterr (core_kd));
 123
 124   gdb_assert (bsd_kvm_supply_pcb);
 125   return bsd_kvm_supply_pcb (current_regcache, &pcb);
 126 }
 127
 128 static void
 129 bsd_kvm_fetch_registers (int regnum)
 130 {
 131   struct nlist nl[2];
 132
 133   if (bsd_kvm_paddr)
 134     {
 135       bsd_kvm_fetch_pcb (bsd_kvm_paddr);
 136       return;
 137     }
 138
 139   /* On dumping core, BSD kernels store the faulting context (PCB)
 140      in the variable "dumppcb".  */
 141   memset (nl, 0, sizeof nl);
 142   nl[0].n_name = "_dumppcb";
 143
 144   if (kvm_nlist (core_kd, nl) == -1)
 145     error ("%s", kvm_geterr (core_kd));
 146
 147   if (nl[0].n_value != 0)
 148     {
 149       /* Found dumppcb. If it contains a valid context, return
 150          immediately.  */
 151       if (bsd_kvm_fetch_pcb ((struct pcb *) nl[0].n_value))
 152         return;
 153     }
 154
 155   /* Traditional BSD kernels have a process proc0 that should always
 156      be present.  The address of proc0's PCB is stored in the variable
 157      "proc0paddr".  */
 158
 159   memset (nl, 0, sizeof nl);
 160   nl[0].n_name = "_proc0paddr";
 161
 162   if (kvm_nlist (core_kd, nl) == -1)
 163     error ("%s", kvm_geterr (core_kd));
 164
 165   if (nl[0].n_value != 0)
 166     {
 167       struct pcb *paddr;
 168
 169       /* Found proc0paddr.  */
 170       if (kvm_read (core_kd, nl[0].n_value, &paddr, sizeof paddr) == -1)
 171         error ("%s", kvm_geterr (core_kd));
 172
 173       bsd_kvm_fetch_pcb (paddr);
 174       return;
 175     }
 176
 177 #ifdef HAVE_STRUCT_THREAD_TD_PCB
 178   /* In FreeBSD kernels for 5.0-RELEASE and later, the PCB no longer
 179      lives in `struct proc' but in `struct thread'.  The `struct
 180      thread' for the initial thread for proc0 can be found in the
 181      variable "thread0".  */
 182
 183   memset (nl, 0, sizeof nl);
 184   nl[0].n_name = "_thread0";
 185
 186   if (kvm_nlist (core_kd, nl) == -1)
 187     error ("%s", kvm_geterr (core_kd));
 188
 189   if (nl[0].n_value != 0)
 190     {
 191       struct pcb *paddr;
 192
 193       /* Found thread0.  */
 194       nl[0].n_value += offsetof (struct thread, td_pcb);
 195       if (kvm_read (core_kd, nl[0].n_value, &paddr, sizeof paddr) == -1)
 196         error ("%s", kvm_geterr (core_kd));
 197
 198       bsd_kvm_fetch_pcb (paddr);
 199       return;
 200     }
 201 #endif
 202
 203   error ("Cannot find a valid PCB");
 204 }
 205 \f
 206
 207 /* Kernel memory interface commands.  */
 208 struct cmd_list_element *bsd_kvm_cmdlist;
 209
 210 static void
 211 bsd_kvm_cmd (char *arg, int fromtty)
 212 {
 213   /* ??? Should this become an alias for "target kvm"?  */
 214 }
 215
 216 #ifndef HAVE_STRUCT_THREAD_TD_PCB
 217
 218 static void
 219 bsd_kvm_proc_cmd (char *arg, int fromtty)
 220 {
 221   CORE_ADDR addr;
 222
 223   if (arg == NULL)
 224     error_no_arg ("proc address");
 225
 226   if (core_kd == NULL)
 227     error ("No kernel memory image.");
 228
 229   addr = parse_and_eval_address (arg);
 230   addr += offsetof (struct proc, p_addr);
 231
 232   if (kvm_read (core_kd, addr, &bsd_kvm_paddr, sizeof bsd_kvm_paddr) == -1)
 233     error ("%s", kvm_geterr (core_kd));
 234
 235   target_fetch_registers (-1);
 236
 237   flush_cached_frames ();
 238   select_frame (get_current_frame ());
 239   print_stack_frame (get_selected_frame (), -1, 1);
 240 }
 241
 242 #endif
 243
 244 static void
 245 bsd_kvm_pcb_cmd (char *arg, int fromtty)
 246 {
 247   if (arg == NULL)
 248     error_no_arg ("pcb address");
 249
 250   if (core_kd == NULL)
 251     error ("No kernel memory image.");
 252
 253   bsd_kvm_paddr = (struct pcb *) parse_and_eval_address (arg);
 254
 255   target_fetch_registers (-1);
 256
 257   flush_cached_frames ();
 258   select_frame (get_current_frame ());
 259   print_stack_frame (get_selected_frame (), -1, 1);
 260 }
 261
 262 /* Add the libkvm interface to the list of all possible targets and
 263    register CUPPLY_PCB as the architecture-specific process control
 264    block interpreter.  */
 265
 266 void
 267 bsd_kvm_add_target (int (*supply_pcb)(struct regcache *, struct pcb *))
 268 {
 269   gdb_assert (bsd_kvm_supply_pcb == NULL);
 270   bsd_kvm_supply_pcb = supply_pcb;
 271
 272   bsd_kvm_ops.to_shortname = "kvm";
 273   bsd_kvm_ops.to_longname = "Kernel memory interface";
 274   bsd_kvm_ops.to_doc = "Use a kernel virtual memory image as a target.\n\
 275 Optionally specify the filename of a core dump.";
 276   bsd_kvm_ops.to_open = bsd_kvm_open;
 277   bsd_kvm_ops.to_close = bsd_kvm_close;
 278   bsd_kvm_ops.to_fetch_registers = bsd_kvm_fetch_registers;
 279   bsd_kvm_ops.to_xfer_memory = bsd_kvm_xfer_memory;
 280   bsd_kvm_ops.to_stratum = process_stratum;
 281   bsd_kvm_ops.to_has_memory = 1;
 282   bsd_kvm_ops.to_has_stack = 1;
 283   bsd_kvm_ops.to_has_registers = 1;
 284   bsd_kvm_ops.to_magic = OPS_MAGIC;
 285
 286   add_target (&bsd_kvm_ops);
 287
 288   add_prefix_cmd ("kvm", class_obscure, bsd_kvm_cmd, "\
 289 Generic command for manipulating the kernel memory interface.",
 290                   &bsd_kvm_cmdlist, "kvm ", 0, &cmdlist);
 291
 292 #ifndef HAVE_STRUCT_THREAD_TD_PCB
 293   add_cmd ("proc", class_obscure, bsd_kvm_proc_cmd,
 294            "Set current context from proc address", &bsd_kvm_cmdlist);
 295 #endif
 296   add_cmd ("pcb", class_obscure, bsd_kvm_pcb_cmd,
 297            "Set current context from pcb address", &bsd_kvm_cmdlist);
 298 }