arch/um/kernel/tt/gdb.c

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