| 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 (NULL), -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 | \f |
| 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 (NULL), -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 *)(u_long) 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 (NULL), -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 | } |