1/* BSD Kernel Data Access Library (libkvm) interface. 2 3 Copyright (C) 2004, 2005, 2007 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 3 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, see <http://www.gnu.org/licenses/>. */ 19 20#include "defs.h" 21#include "cli/cli-cmds.h" 22#include "command.h" 23#include "frame.h" 24#include "regcache.h" 25#include "target.h" 26#include "value.h" 27#include "gdbcore.h" /* for get_exec_file */ 28 29#include "gdb_assert.h" 30#include <fcntl.h> 31#include <kvm.h> 32#ifdef HAVE_NLIST_H 33#include <nlist.h> 34#endif 35#include <paths.h> 36#include "readline/readline.h" 37#include <sys/param.h> 38#include <sys/proc.h> 39#include <sys/user.h> 40 41#include "bsd-kvm.h" 42 43/* Kernel memory device file. */ 44static const char *bsd_kvm_corefile; 45 46/* Kernel memory interface descriptor. */ 47static kvm_t *core_kd; 48 49/* Address of process control block. */ 50static struct pcb *bsd_kvm_paddr; 51 52/* Pointer to architecture-specific function that reconstructs the 53 register state from PCB and supplies it to REGCACHE. */ 54static int (*bsd_kvm_supply_pcb)(struct regcache *regcache, struct pcb *pcb); 55 56/* Target ops for libkvm interface. */ 57static struct target_ops bsd_kvm_ops; 58 59static void 60bsd_kvm_open (char *filename, int from_tty) 61{ 62 char errbuf[_POSIX2_LINE_MAX]; 63 char *execfile = NULL; 64 kvm_t *temp_kd; 65 66 target_preopen (from_tty); 67 68 if (filename) 69 { 70 char *temp; 71 72 filename = tilde_expand (filename); 73 if (filename[0] != '/') 74 { 75 temp = concat (current_directory, "/", filename, (char *)NULL); 76 xfree (filename); 77 filename = temp; 78 } 79 } 80 81 execfile = get_exec_file (0); 82 temp_kd = kvm_openfiles (execfile, filename, NULL, 83 write_files ? O_RDWR : O_RDONLY, errbuf); 84 if (temp_kd == NULL) 85 error (("%s"), errbuf); 86 87 bsd_kvm_corefile = filename; 88 unpush_target (&bsd_kvm_ops); 89 core_kd = temp_kd; 90 push_target (&bsd_kvm_ops); 91 92 target_fetch_registers (get_current_regcache (), -1); 93 94 reinit_frame_cache (); 95 print_stack_frame (get_selected_frame (NULL), -1, 1); 96} 97 98static void 99bsd_kvm_close (int quitting) 100{ 101 if (core_kd) 102 { 103 if (kvm_close (core_kd) == -1) 104 warning (("%s"), kvm_geterr(core_kd)); 105 core_kd = NULL; 106 } 107} 108 109static LONGEST 110bsd_kvm_xfer_memory (CORE_ADDR addr, ULONGEST len, 111 gdb_byte *readbuf, const gdb_byte *writebuf) 112{ 113 ssize_t nbytes = len; 114 115 if (readbuf) 116 nbytes = kvm_read (core_kd, addr, readbuf, nbytes); 117 if (writebuf && nbytes > 0) 118 nbytes = kvm_write (core_kd, addr, writebuf, nbytes); 119 return nbytes; 120} 121 122static LONGEST 123bsd_kvm_xfer_partial (struct target_ops *ops, enum target_object object, 124 const char *annex, gdb_byte *readbuf, 125 const gdb_byte *writebuf, 126 ULONGEST offset, LONGEST len) 127{ 128 switch (object) 129 { 130 case TARGET_OBJECT_MEMORY: 131 return bsd_kvm_xfer_memory (offset, len, readbuf, writebuf); 132 133 default: 134 return -1; 135 } 136} 137 138static void 139bsd_kvm_files_info (struct target_ops *ops) 140{ 141 if (bsd_kvm_corefile && strcmp (bsd_kvm_corefile, _PATH_MEM) != 0) 142 printf_filtered (_("\tUsing the kernel crash dump %s.\n"), 143 bsd_kvm_corefile); 144 else 145 printf_filtered (_("\tUsing the currently running kernel.\n")); 146} 147 148/* Fetch process control block at address PADDR. */ 149 150static int 151bsd_kvm_fetch_pcb (struct regcache *regcache, struct pcb *paddr) 152{ 153 struct pcb pcb; 154 155 if (kvm_read (core_kd, (unsigned long) paddr, &pcb, sizeof pcb) == -1) 156 error (("%s"), kvm_geterr (core_kd)); 157 158 gdb_assert (bsd_kvm_supply_pcb); 159 return bsd_kvm_supply_pcb (regcache, &pcb); 160} 161 162static void 163bsd_kvm_fetch_registers (struct regcache *regcache, int regnum) 164{ 165 struct nlist nl[2]; 166 167 if (bsd_kvm_paddr) 168 { 169 bsd_kvm_fetch_pcb (regcache, bsd_kvm_paddr); 170 return; 171 } 172 173 /* On dumping core, BSD kernels store the faulting context (PCB) 174 in the variable "dumppcb". */ 175 memset (nl, 0, sizeof nl); 176 nl[0].n_name = "_dumppcb"; 177 178 if (kvm_nlist (core_kd, nl) == -1) 179 error (("%s"), kvm_geterr (core_kd)); 180 181 if (nl[0].n_value != 0) 182 { 183 /* Found dumppcb. If it contains a valid context, return 184 immediately. */ 185 if (bsd_kvm_fetch_pcb (regcache, (struct pcb *) nl[0].n_value)) 186 return; 187 } 188 189 /* Traditional BSD kernels have a process proc0 that should always 190 be present. The address of proc0's PCB is stored in the variable 191 "proc0paddr". */ 192 193 memset (nl, 0, sizeof nl); 194 nl[0].n_name = "_proc0paddr"; 195 196 if (kvm_nlist (core_kd, nl) == -1) 197 error (("%s"), kvm_geterr (core_kd)); 198 199 if (nl[0].n_value != 0) 200 { 201 struct pcb *paddr; 202 203 /* Found proc0paddr. */ 204 if (kvm_read (core_kd, nl[0].n_value, &paddr, sizeof paddr) == -1) 205 error (("%s"), kvm_geterr (core_kd)); 206 207 bsd_kvm_fetch_pcb (regcache, paddr); 208 return; 209 } 210 211#ifdef HAVE_STRUCT_THREAD_TD_PCB 212 /* In FreeBSD kernels for 5.0-RELEASE and later, the PCB no longer 213 lives in `struct proc' but in `struct thread'. The `struct 214 thread' for the initial thread for proc0 can be found in the 215 variable "thread0". */ 216 217 memset (nl, 0, sizeof nl); 218 nl[0].n_name = "_thread0"; 219 220 if (kvm_nlist (core_kd, nl) == -1) 221 error (("%s"), kvm_geterr (core_kd)); 222 223 if (nl[0].n_value != 0) 224 { 225 struct pcb *paddr; 226 227 /* Found thread0. */ 228 nl[0].n_value += offsetof (struct thread, td_pcb); 229 if (kvm_read (core_kd, nl[0].n_value, &paddr, sizeof paddr) == -1) 230 error (("%s"), kvm_geterr (core_kd)); 231 232 bsd_kvm_fetch_pcb (regcache, paddr); 233 return; 234 } 235#endif 236 237 /* i18n: PCB == "Process Control Block" */ 238 error (_("Cannot find a valid PCB")); 239} 240 241 242/* Kernel memory interface commands. */ 243struct cmd_list_element *bsd_kvm_cmdlist; 244 245static void 246bsd_kvm_cmd (char *arg, int fromtty) 247{ 248 /* ??? Should this become an alias for "target kvm"? */ 249} 250 251#ifndef HAVE_STRUCT_THREAD_TD_PCB 252 253static void 254bsd_kvm_proc_cmd (char *arg, int fromtty) 255{ 256 CORE_ADDR addr; 257 258 if (arg == NULL) 259 error_no_arg (_("proc address")); 260 261 if (core_kd == NULL) 262 error (_("No kernel memory image.")); 263 264 addr = parse_and_eval_address (arg); 265#ifdef HAVE_STRUCT_LWP 266 addr += offsetof (struct lwp, l_addr); 267#else 268 addr += offsetof (struct proc, p_addr); 269#endif 270 271 if (kvm_read (core_kd, addr, &bsd_kvm_paddr, sizeof bsd_kvm_paddr) == -1) 272 error (("%s"), kvm_geterr (core_kd)); 273 274 target_fetch_registers (get_current_regcache (), -1); 275 276 reinit_frame_cache (); 277 print_stack_frame (get_selected_frame (NULL), -1, 1); 278} 279 280#endif 281 282static void 283bsd_kvm_pcb_cmd (char *arg, int fromtty) 284{ 285 if (arg == NULL) 286 /* i18n: PCB == "Process Control Block" */ 287 error_no_arg (_("pcb address")); 288 289 if (core_kd == NULL) 290 error (_("No kernel memory image.")); 291 292 bsd_kvm_paddr = (struct pcb *)(u_long) parse_and_eval_address (arg); 293 294 target_fetch_registers (get_current_regcache (), -1); 295 296 reinit_frame_cache (); 297 print_stack_frame (get_selected_frame (NULL), -1, 1); 298} 299 300/* Add the libkvm interface to the list of all possible targets and 301 register CUPPLY_PCB as the architecture-specific process control 302 block interpreter. */ 303 304void 305bsd_kvm_add_target (int (*supply_pcb)(struct regcache *, struct pcb *)) 306{ 307 gdb_assert (bsd_kvm_supply_pcb == NULL); 308 bsd_kvm_supply_pcb = supply_pcb; 309 310 bsd_kvm_ops.to_shortname = "kvm"; 311 bsd_kvm_ops.to_longname = _("Kernel memory interface"); 312 bsd_kvm_ops.to_doc = _("Use a kernel virtual memory image as a target.\n\ 313Optionally specify the filename of a core dump."); 314 bsd_kvm_ops.to_open = bsd_kvm_open; 315 bsd_kvm_ops.to_close = bsd_kvm_close; 316 bsd_kvm_ops.to_fetch_registers = bsd_kvm_fetch_registers; 317 bsd_kvm_ops.to_xfer_partial = bsd_kvm_xfer_partial; 318 bsd_kvm_ops.to_files_info = bsd_kvm_files_info; 319 bsd_kvm_ops.to_stratum = process_stratum; 320 bsd_kvm_ops.to_has_memory = 1; 321 bsd_kvm_ops.to_has_stack = 1; 322 bsd_kvm_ops.to_has_registers = 1; 323 bsd_kvm_ops.to_magic = OPS_MAGIC; 324 325 add_target (&bsd_kvm_ops); 326 327 add_prefix_cmd ("kvm", class_obscure, bsd_kvm_cmd, _("\ 328Generic command for manipulating the kernel memory interface."), 329 &bsd_kvm_cmdlist, "kvm ", 0, &cmdlist); 330 331#ifndef HAVE_STRUCT_THREAD_TD_PCB 332 add_cmd ("proc", class_obscure, bsd_kvm_proc_cmd, 333 _("Set current context from proc address"), &bsd_kvm_cmdlist); 334#endif 335 add_cmd ("pcb", class_obscure, bsd_kvm_pcb_cmd, 336 /* i18n: PCB == "Process Control Block" */ 337 _("Set current context from pcb address"), &bsd_kvm_cmdlist); 338} 339