1/*
2 * Copyright (C) 2002 Jeff Dike (jdike@karaya.com)
3 * Licensed under the GPL
4 */
5
6#include <stdio.h>
7#include <stdlib.h>
8#include <errno.h>
9#include <string.h>
10#include <signal.h>
11#include <sys/types.h>
12#include "ptrace_user.h"
13#include "uml-config.h"
14#include "kern_constants.h"
15#include "chan_user.h"
16#include "init.h"
17#include "user.h"
18#include "debug.h"
19#include "kern_util.h"
20#include "tt.h"
21#include "sysdep/thread.h"
22#include "os.h"
23
24extern int debugger_pid;
25extern int debugger_fd;
26extern int debugger_parent;
27
28int detach(int pid, int sig)
29{
30	return(ptrace(PTRACE_DETACH, pid, 0, sig));
31}
32
33int attach(int pid)
34{
35	int err;
36
37	err = ptrace(PTRACE_ATTACH, pid, 0, 0);
38	if(err < 0) return(-errno);
39	else return(err);
40}
41
42int cont(int pid)
43{
44	return(ptrace(PTRACE_CONT, pid, 0, 0));
45}
46
47#ifdef UML_CONFIG_PT_PROXY
48
49int debugger_signal(int status, pid_t pid)
50{
51	return(debugger_proxy(status, pid));
52}
53
54void child_signal(pid_t pid, int status)
55{
56	child_proxy(pid, status);
57}
58
59static void gdb_announce(char *dev_name, int dev)
60{
61	printf("gdb assigned device '%s'\n", dev_name);
62}
63
64static struct chan_opts opts = {
65	.announce  	= gdb_announce,
66	.xterm_title 	= "UML kernel debugger",
67	.raw 		= 0,
68	.tramp_stack 	= 0,
69	.in_kernel  	= 0,
70};
71
72/* Accessed by the tracing thread, which automatically serializes access */
73static void *xterm_data;
74static int xterm_fd;
75
76extern void *xterm_init(char *, int, struct chan_opts *);
77extern int xterm_open(int, int, int, void *, char **);
78extern void xterm_close(int, void *);
79
80int open_gdb_chan(void)
81{
82	char stack[UM_KERN_PAGE_SIZE], *dummy;
83
84	opts.tramp_stack = (unsigned long) stack;
85	xterm_data = xterm_init("", 0, &opts);
86	xterm_fd = xterm_open(1, 1, 1, xterm_data, &dummy);
87	return(xterm_fd);
88}
89
90static void exit_debugger_cb(void *unused)
91{
92	if(debugger_pid != -1){
93		if(gdb_pid != -1){
94			fake_child_exit();
95			gdb_pid = -1;
96		}
97		else kill_child_dead(debugger_pid);
98		debugger_pid = -1;
99		if(debugger_parent != -1)
100			detach(debugger_parent, SIGINT);
101	}
102	if(xterm_data != NULL) xterm_close(xterm_fd, xterm_data);
103}
104
105static void exit_debugger(void)
106{
107	initial_thread_cb(exit_debugger_cb, NULL);
108}
109
110__uml_exitcall(exit_debugger);
111
112struct gdb_data {
113	char *str;
114	int err;
115};
116
117extern char *linux_prog;
118
119static void config_gdb_cb(void *arg)
120{
121	struct gdb_data *data = arg;
122	void *task;
123	int pid;
124
125	data->err = -1;
126	if(debugger_pid != -1) exit_debugger_cb(NULL);
127	if(!strncmp(data->str, "pid,", strlen("pid,"))){
128		data->str += strlen("pid,");
129		pid = strtoul(data->str, NULL, 0);
130		task = cpu_tasks[0].task;
131		debugger_pid = attach_debugger(TASK_EXTERN_PID(task), pid, 0);
132		if(debugger_pid != -1){
133			data->err = 0;
134			gdb_pid = pid;
135		}
136		return;
137	}
138	data->err = 0;
139	debugger_pid = start_debugger(linux_prog, 0, 0, &debugger_fd);
140	init_proxy(debugger_pid, 0, 0);
141}
142
143int gdb_config(char *str, char **error_out)
144{
145	struct gdb_data data;
146
147	if(*str++ != '=') return(-1);
148	data.str = str;
149	initial_thread_cb(config_gdb_cb, &data);
150	return(data.err);
151}
152
153void remove_gdb_cb(void *unused)
154{
155	exit_debugger_cb(NULL);
156}
157
158int gdb_remove(int unused, char **error_out)
159{
160	initial_thread_cb(remove_gdb_cb, NULL);
161        return 0;
162}
163
164void signal_usr1(int sig)
165{
166	if(debugger_pid != -1){
167		printf("The debugger is already running\n");
168		return;
169	}
170	debugger_pid = start_debugger(linux_prog, 0, 0, &debugger_fd);
171	init_proxy(debugger_pid, 0, 0);
172}
173
174int init_ptrace_proxy(int idle_pid, int startup, int stop)
175{
176	int pid, status;
177
178	pid = start_debugger(linux_prog, startup, stop, &debugger_fd);
179	status = wait_for_stop(idle_pid, SIGSTOP, PTRACE_CONT, NULL);
180 	if(pid < 0){
181		cont(idle_pid);
182		return(-1);
183	}
184	init_proxy(pid, 1, status);
185	return(pid);
186}
187
188int attach_debugger(int idle_pid, int pid, int stop)
189{
190	int status = 0, err;
191
192	err = attach(pid);
193	if(err < 0){
194		printf("Failed to attach pid %d, errno = %d\n", pid, -err);
195		return(-1);
196	}
197	if(stop) status = wait_for_stop(idle_pid, SIGSTOP, PTRACE_CONT, NULL);
198	init_proxy(pid, 1, status);
199	return(pid);
200}
201
202#ifdef notdef     /* Put this back in when it does something useful */
203static int __init uml_gdb_init_setup(char *line, int *add)
204{
205	gdb_init = uml_strdup(line);
206	return 0;
207}
208
209__uml_setup("gdb=", uml_gdb_init_setup,
210"gdb=<channel description>\n\n"
211);
212#endif
213
214static int __init uml_gdb_pid_setup(char *line, int *add)
215{
216	gdb_pid = strtoul(line, NULL, 0);
217	*add = 0;
218	return 0;
219}
220
221__uml_setup("gdb-pid=", uml_gdb_pid_setup,
222"gdb-pid=<pid>\n"
223"    gdb-pid is used to attach an external debugger to UML.  This may be\n"
224"    an already-running gdb or a debugger-like process like strace.\n\n"
225);
226
227#else
228
229int debugger_signal(int status, pid_t pid){ return(0); }
230void child_signal(pid_t pid, int status){ }
231int init_ptrace_proxy(int idle_pid, int startup, int stop)
232{
233	printf("debug requested when CONFIG_PT_PROXY is off\n");
234	kill_child_dead(idle_pid);
235	exit(1);
236}
237
238void signal_usr1(int sig)
239{
240	printf("debug requested when CONFIG_PT_PROXY is off\n");
241}
242
243int attach_debugger(int idle_pid, int pid, int stop)
244{
245	printf("attach_debugger called when CONFIG_PT_PROXY "
246	       "is off\n");
247	return(-1);
248}
249
250int config_gdb(char *str)
251{
252	return(-1);
253}
254
255int remove_gdb(void)
256{
257	return(-1);
258}
259
260int init_parent_proxy(int pid)
261{
262	return(-1);
263}
264
265void debugger_parent_signal(int status, int pid)
266{
267}
268
269#endif
270
271/*
272 * Overrides for Emacs so that we follow Linus's tabbing style.
273 * Emacs will notice this stuff at the end of the file and automatically
274 * adjust the settings for this buffer only.  This must remain at the end
275 * of the file.
276 * ---------------------------------------------------------------------------
277 * Local variables:
278 * c-file-style: "linux"
279 * End:
280 */
281