083bc92c2977d8cca58cf5e54d356eba7989ddff
[deliverable/binutils-gdb.git] / 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 #include "gdbcore.h" /* for get_exec_file */
30
31 #include "gdb_assert.h"
32 #include <fcntl.h>
33 #include <kvm.h>
34 #include <nlist.h>
35 #include "readline/readline.h"
36 #include <sys/param.h>
37 #include <sys/proc.h>
38 #include <sys/user.h>
39
40 #include "bsd-kvm.h"
41
42 /* Kernel memory interface descriptor. */
43 kvm_t *core_kd;
44
45 /* Address of process control block. */
46 struct pcb *bsd_kvm_paddr;
47
48 /* Pointer to architecture-specific function that reconstructs the
49 register state from PCB and supplies it to REGCACHE. */
50 int (*bsd_kvm_supply_pcb)(struct regcache *regcache, struct pcb *pcb);
51
52 /* Target ops for libkvm interface. */
53 struct target_ops bsd_kvm_ops;
54
55 static void
56 bsd_kvm_open (char *filename, int from_tty)
57 {
58 char errbuf[_POSIX2_LINE_MAX];
59 char *execfile = NULL;
60 kvm_t *temp_kd;
61
62 target_preopen (from_tty);
63
64 if (filename)
65 {
66 char *temp;
67
68 filename = tilde_expand (filename);
69 if (filename[0] != '/')
70 {
71 temp = concat (current_directory, "/", filename, NULL);
72 xfree (filename);
73 filename = temp;
74 }
75 }
76
77 execfile = get_exec_file (0);
78 temp_kd = kvm_openfiles (execfile, filename, NULL, O_RDONLY, errbuf);
79 if (temp_kd == NULL)
80 error ("%s", errbuf);
81
82 unpush_target (&bsd_kvm_ops);
83 core_kd = temp_kd;
84 push_target (&bsd_kvm_ops);
85
86 target_fetch_registers (-1);
87
88 flush_cached_frames ();
89 select_frame (get_current_frame ());
90 print_stack_frame (get_selected_frame (), -1, 1);
91 }
92
93 static void
94 bsd_kvm_close (int quitting)
95 {
96 if (core_kd)
97 {
98 if (kvm_close (core_kd) == -1)
99 warning ("%s", kvm_geterr(core_kd));
100 core_kd = NULL;
101 }
102 }
103
104 static int
105 bsd_kvm_xfer_memory (CORE_ADDR memaddr, char *myaddr, int len,
106 int write, struct mem_attrib *attrib,
107 struct target_ops *ops)
108 {
109 if (write)
110 return kvm_write (core_kd, memaddr, myaddr, len);
111 else
112 return kvm_read (core_kd, memaddr, myaddr, len);
113
114 return -1;
115 }
116
117 /* Fetch process control block at address PADDR. */
118
119 static int
120 bsd_kvm_fetch_pcb (struct pcb *paddr)
121 {
122 struct pcb pcb;
123
124 if (kvm_read (core_kd, (unsigned long) paddr, &pcb, sizeof pcb) == -1)
125 error ("%s", kvm_geterr (core_kd));
126
127 gdb_assert (bsd_kvm_supply_pcb);
128 return bsd_kvm_supply_pcb (current_regcache, &pcb);
129 }
130
131 static void
132 bsd_kvm_fetch_registers (int regnum)
133 {
134 struct nlist nl[2];
135
136 if (bsd_kvm_paddr)
137 {
138 bsd_kvm_fetch_pcb (bsd_kvm_paddr);
139 return;
140 }
141
142 /* On dumping core, BSD kernels store the faulting context (PCB)
143 in the variable "dumppcb". */
144 memset (nl, 0, sizeof nl);
145 nl[0].n_name = "_dumppcb";
146
147 if (kvm_nlist (core_kd, nl) == -1)
148 error ("%s", kvm_geterr (core_kd));
149
150 if (nl[0].n_value != 0)
151 {
152 /* Found dumppcb. If it contains a valid context, return
153 immediately. */
154 if (bsd_kvm_fetch_pcb ((struct pcb *) nl[0].n_value))
155 return;
156 }
157
158 /* Traditional BSD kernels have a process proc0 that should always
159 be present. The address of proc0's PCB is stored in the variable
160 "proc0paddr". */
161
162 memset (nl, 0, sizeof nl);
163 nl[0].n_name = "_proc0paddr";
164
165 if (kvm_nlist (core_kd, nl) == -1)
166 error ("%s", kvm_geterr (core_kd));
167
168 if (nl[0].n_value != 0)
169 {
170 struct pcb *paddr;
171
172 /* Found proc0paddr. */
173 if (kvm_read (core_kd, nl[0].n_value, &paddr, sizeof paddr) == -1)
174 error ("%s", kvm_geterr (core_kd));
175
176 bsd_kvm_fetch_pcb (paddr);
177 return;
178 }
179
180 #ifdef HAVE_STRUCT_THREAD_TD_PCB
181 /* In FreeBSD kernels for 5.0-RELEASE and later, the PCB no longer
182 lives in `struct proc' but in `struct thread'. The `struct
183 thread' for the initial thread for proc0 can be found in the
184 variable "thread0". */
185
186 memset (nl, 0, sizeof nl);
187 nl[0].n_name = "_thread0";
188
189 if (kvm_nlist (core_kd, nl) == -1)
190 error ("%s", kvm_geterr (core_kd));
191
192 if (nl[0].n_value != 0)
193 {
194 struct pcb *paddr;
195
196 /* Found thread0. */
197 nl[0].n_value += offsetof (struct thread, td_pcb);
198 if (kvm_read (core_kd, nl[0].n_value, &paddr, sizeof paddr) == -1)
199 error ("%s", kvm_geterr (core_kd));
200
201 bsd_kvm_fetch_pcb (paddr);
202 return;
203 }
204 #endif
205
206 error ("Cannot find a valid PCB");
207 }
208 \f
209
210 /* Kernel memory interface commands. */
211 struct cmd_list_element *bsd_kvm_cmdlist;
212
213 static void
214 bsd_kvm_cmd (char *arg, int fromtty)
215 {
216 /* ??? Should this become an alias for "target kvm"? */
217 }
218
219 #ifndef HAVE_STRUCT_THREAD_TD_PCB
220
221 static void
222 bsd_kvm_proc_cmd (char *arg, int fromtty)
223 {
224 CORE_ADDR addr;
225
226 if (arg == NULL)
227 error_no_arg ("proc address");
228
229 if (core_kd == NULL)
230 error ("No kernel memory image.");
231
232 addr = parse_and_eval_address (arg);
233 #ifdef HAVE_STRUCT_LWP
234 addr += offsetof (struct lwp, l_addr);
235 #else
236 addr += offsetof (struct proc, p_addr);
237 #endif
238
239 if (kvm_read (core_kd, addr, &bsd_kvm_paddr, sizeof bsd_kvm_paddr) == -1)
240 error ("%s", kvm_geterr (core_kd));
241
242 target_fetch_registers (-1);
243
244 flush_cached_frames ();
245 select_frame (get_current_frame ());
246 print_stack_frame (get_selected_frame (), -1, 1);
247 }
248
249 #endif
250
251 static void
252 bsd_kvm_pcb_cmd (char *arg, int fromtty)
253 {
254 if (arg == NULL)
255 error_no_arg ("pcb address");
256
257 if (core_kd == NULL)
258 error ("No kernel memory image.");
259
260 bsd_kvm_paddr = (struct pcb *) parse_and_eval_address (arg);
261
262 target_fetch_registers (-1);
263
264 flush_cached_frames ();
265 select_frame (get_current_frame ());
266 print_stack_frame (get_selected_frame (), -1, 1);
267 }
268
269 /* Add the libkvm interface to the list of all possible targets and
270 register CUPPLY_PCB as the architecture-specific process control
271 block interpreter. */
272
273 void
274 bsd_kvm_add_target (int (*supply_pcb)(struct regcache *, struct pcb *))
275 {
276 gdb_assert (bsd_kvm_supply_pcb == NULL);
277 bsd_kvm_supply_pcb = supply_pcb;
278
279 bsd_kvm_ops.to_shortname = "kvm";
280 bsd_kvm_ops.to_longname = "Kernel memory interface";
281 bsd_kvm_ops.to_doc = "Use a kernel virtual memory image as a target.\n\
282 Optionally specify the filename of a core dump.";
283 bsd_kvm_ops.to_open = bsd_kvm_open;
284 bsd_kvm_ops.to_close = bsd_kvm_close;
285 bsd_kvm_ops.to_fetch_registers = bsd_kvm_fetch_registers;
286 bsd_kvm_ops.to_xfer_memory = bsd_kvm_xfer_memory;
287 bsd_kvm_ops.to_stratum = process_stratum;
288 bsd_kvm_ops.to_has_memory = 1;
289 bsd_kvm_ops.to_has_stack = 1;
290 bsd_kvm_ops.to_has_registers = 1;
291 bsd_kvm_ops.to_magic = OPS_MAGIC;
292
293 add_target (&bsd_kvm_ops);
294
295 add_prefix_cmd ("kvm", class_obscure, bsd_kvm_cmd, "\
296 Generic command for manipulating the kernel memory interface.",
297 &bsd_kvm_cmdlist, "kvm ", 0, &cmdlist);
298
299 #ifndef HAVE_STRUCT_THREAD_TD_PCB
300 add_cmd ("proc", class_obscure, bsd_kvm_proc_cmd,
301 "Set current context from proc address", &bsd_kvm_cmdlist);
302 #endif
303 add_cmd ("pcb", class_obscure, bsd_kvm_pcb_cmd,
304 "Set current context from pcb address", &bsd_kvm_cmdlist);
305 }
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