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 "tt.h"
  21 #include "sysdep/thread.h"
  22 #include "os.h"
  23
  24 extern int debugger_pid;
  25 extern int debugger_fd;
  26 extern int debugger_parent;
  27
  28 int detach(int pid, int sig)
  29 {
  30         return(ptrace(PTRACE_DETACH, pid, 0, sig));
  31 }
  32
  33 int 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
  42 int cont(int pid)
  43 {
  44         return(ptrace(PTRACE_CONT, pid, 0, 0));
  45 }
  46
  47 #ifdef UML_CONFIG_PT_PROXY
  48
  49 int debugger_signal(int status, pid_t pid)
  50 {
  51         return(debugger_proxy(status, pid));
  52 }
  53
  54 void child_signal(pid_t pid, int status)
  55 {
  56         child_proxy(pid, status);
  57 }
  58
  59 static void gdb_announce(char *dev_name, int dev)
  60 {
  61         printf("gdb assigned device '%s'\n", dev_name);
  62 }
  63
  64 static 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 */
  73 static void *xterm_data;
  74 static int xterm_fd;
  75
  76 extern void *xterm_init(char *, int, struct chan_opts *);
  77 extern int xterm_open(int, int, int, void *, char **);
  78 extern void xterm_close(int, void *);
  79
  80 int 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
  90 static 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
 105 static void exit_debugger(void)
 106 {
 107         initial_thread_cb(exit_debugger_cb, NULL);
 108 }
 109
 110 __uml_exitcall(exit_debugger);
 111
 112 struct gdb_data {
 113         char *str;
 114         int err;
 115 };
 116
 117 extern char *linux_prog;
 118
 119 static 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
 143 int 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
 153 void remove_gdb_cb(void *unused)
 154 {
 155         exit_debugger_cb(NULL);
 156 }
 157
 158 int gdb_remove(int unused, char **error_out)
 159 {
 160         initial_thread_cb(remove_gdb_cb, NULL);
 161         return 0;
 162 }
 163
 164 void 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
 174 int 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
 188 int 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 */
 203 static 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
 214 static 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
 229 int debugger_signal(int status, pid_t pid){ return(0); }
 230 void child_signal(pid_t pid, int status){ }
 231 int 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
 238 void signal_usr1(int sig)
 239 {
 240         printf("debug requested when CONFIG_PT_PROXY is off\n");
 241 }
 242
 243 int 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
 250 int config_gdb(char *str)
 251 {
 252         return(-1);
 253 }
 254
 255 int remove_gdb(void)
 256 {
 257         return(-1);
 258 }
 259
 260 int init_parent_proxy(int pid)
 261 {
 262         return(-1);
 263 }
 264
 265 void 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  */