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