arch/um/kernel/ptrace.c

   1 /*
   2  * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/sched.h"
   7 #include "linux/mm.h"
   8 #include "linux/errno.h"
   9 #include "linux/smp_lock.h"
  10 #include "linux/security.h"
  11 #include "linux/ptrace.h"
  12 #ifdef CONFIG_PROC_MM
  13 #include "linux/proc_mm.h"
  14 #endif
  15 #include "asm/ptrace.h"
  16 #include "asm/uaccess.h"
  17 #include "kern_util.h"
  18 #include "ptrace_user.h"
  19
  20 /*
  21  * Called by kernel/ptrace.c when detaching..
  22  */
  23 void ptrace_disable(struct task_struct *child)
  24 {
  25 }
  26
  27 extern long do_mmap2(struct task_struct *task, unsigned long addr,
  28                      unsigned long len, unsigned long prot,
  29                      unsigned long flags, unsigned long fd,
  30                      unsigned long pgoff);
  31
  32 int sys_ptrace(long request, long pid, long addr, long data)
  33 {
  34         struct task_struct *child;
  35         int i, ret;
  36
  37         lock_kernel();
  38         ret = -EPERM;
  39         if (request == PTRACE_TRACEME) {
  40                 /* are we already being traced? */
  41                 if (current->ptrace & PT_PTRACED)
  42                         goto out;
  43
  44                 ret = security_ptrace(current->parent, current);
  45                 if (ret)
  46                         goto out;
  47
  48                 /* set the ptrace bit in the process flags. */
  49                 current->ptrace |= PT_PTRACED;
  50                 ret = 0;
  51                 goto out;
  52         }
  53         ret = -ESRCH;
  54         read_lock(&tasklist_lock);
  55         child = find_task_by_pid(pid);
  56         if (child)
  57                 get_task_struct(child);
  58         read_unlock(&tasklist_lock);
  59         if (!child)
  60                 goto out;
  61
  62         ret = -EPERM;
  63         if (pid == 1)           /* you may not mess with init */
  64                 goto out_tsk;
  65
  66         if (request == PTRACE_ATTACH) {
  67                 ret = ptrace_attach(child);
  68                 goto out_tsk;
  69         }
  70
  71         ret = ptrace_check_attach(child, request == PTRACE_KILL);
  72         if (ret < 0)
  73                 goto out_tsk;
  74
  75         switch (request) {
  76                 /* when I and D space are separate, these will need to be fixed. */
  77         case PTRACE_PEEKTEXT: /* read word at location addr. */
  78         case PTRACE_PEEKDATA: {
  79                 unsigned long tmp;
  80                 int copied;
  81
  82                 ret = -EIO;
  83                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
  84                 if (copied != sizeof(tmp))
  85                         break;
  86                 ret = put_user(tmp,(unsigned long *) data);
  87                 break;
  88         }
  89
  90         /* read the word at location addr in the USER area. */
  91         case PTRACE_PEEKUSR: {
  92                 unsigned long tmp;
  93
  94                 ret = -EIO;
  95                 if ((addr & 3) || addr < 0)
  96                         break;
  97
  98                 tmp = 0;  /* Default return condition */
  99                 if(addr < FRAME_SIZE_OFFSET){
 100                         tmp = getreg(child, addr);
 101                 }
 102                 else if((addr >= offsetof(struct user, u_debugreg[0])) &&
 103                         (addr <= offsetof(struct user, u_debugreg[7]))){
 104                         addr -= offsetof(struct user, u_debugreg[0]);
 105                         addr = addr >> 2;
 106                         tmp = child->thread.arch.debugregs[addr];
 107                 }
 108                 ret = put_user(tmp, (unsigned long *) data);
 109                 break;
 110         }
 111
 112         /* when I and D space are separate, this will have to be fixed. */
 113         case PTRACE_POKETEXT: /* write the word at location addr. */
 114         case PTRACE_POKEDATA:
 115                 ret = -EIO;
 116                 if (access_process_vm(child, addr, &data, sizeof(data),
 117                                       1) != sizeof(data))
 118                         break;
 119                 ret = 0;
 120                 break;
 121
 122         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 123                 ret = -EIO;
 124                 if ((addr & 3) || addr < 0)
 125                         break;
 126
 127                 if (addr < FRAME_SIZE_OFFSET) {
 128                         ret = putreg(child, addr, data);
 129                         break;
 130                 }
 131                 else if((addr >= offsetof(struct user, u_debugreg[0])) &&
 132                         (addr <= offsetof(struct user, u_debugreg[7]))){
 133                           addr -= offsetof(struct user, u_debugreg[0]);
 134                           addr = addr >> 2;
 135                           if((addr == 4) || (addr == 5)) break;
 136                           child->thread.arch.debugregs[addr] = data;
 137                           ret = 0;
 138                 }
 139
 140                 break;
 141
 142         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 143         case PTRACE_CONT: { /* restart after signal. */
 144                 ret = -EIO;
 145                 if ((unsigned long) data > _NSIG)
 146                         break;
 147                 if (request == PTRACE_SYSCALL) {
 148                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 149                 }
 150                 else {
 151                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 152                 }
 153                 child->exit_code = data;
 154                 wake_up_process(child);
 155                 ret = 0;
 156                 break;
 157         }
 158
 159 /*
 160  * make the child exit.  Best I can do is send it a sigkill.
 161  * perhaps it should be put in the status that it wants to
 162  * exit.
 163  */
 164         case PTRACE_KILL: {
 165                 ret = 0;
 166                 if (child->state == TASK_ZOMBIE)        /* already dead */
 167                         break;
 168                 child->exit_code = SIGKILL;
 169                 wake_up_process(child);
 170                 break;
 171         }
 172
 173         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 174                 ret = -EIO;
 175                 if ((unsigned long) data > _NSIG)
 176                         break;
 177                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 178                 child->ptrace |= PT_DTRACE;
 179                 child->exit_code = data;
 180                 /* give it a chance to run. */
 181                 wake_up_process(child);
 182                 ret = 0;
 183                 break;
 184         }
 185
 186         case PTRACE_DETACH:
 187                 /* detach a process that was attached. */
 188                 ret = ptrace_detach(child, data);
 189                 break;
 190
 191 #ifdef PTRACE_GETREGS
 192         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 193                 if (!access_ok(VERIFY_WRITE, (unsigned long *)data,
 194                                FRAME_SIZE_OFFSET)) {
 195                         ret = -EIO;
 196                         break;
 197                 }
 198                 for ( i = 0; i < FRAME_SIZE_OFFSET; i += sizeof(long) ) {
 199                         __put_user(getreg(child, i), (unsigned long *) data);
 200                         data += sizeof(long);
 201                 }
 202                 ret = 0;
 203                 break;
 204         }
 205 #endif
 206 #ifdef PTRACE_SETREGS
 207         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 208                 unsigned long tmp = 0;
 209                 if (!access_ok(VERIFY_READ, (unsigned *)data,
 210                                FRAME_SIZE_OFFSET)) {
 211                         ret = -EIO;
 212                         break;
 213                 }
 214                 for ( i = 0; i < FRAME_SIZE_OFFSET; i += sizeof(long) ) {
 215                         __get_user(tmp, (unsigned long *) data);
 216                         putreg(child, i, tmp);
 217                         data += sizeof(long);
 218                 }
 219                 ret = 0;
 220                 break;
 221         }
 222 #endif
 223 #ifdef PTRACE_GETFPREGS
 224         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 225                 ret = get_fpregs(data, child);
 226                 break;
 227 #endif
 228 #ifdef PTRACE_SETFPREGS
 229         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 230                 ret = set_fpregs(data, child);
 231                 break;
 232 #endif
 233 #ifdef PTRACE_GETFPXREGS
 234         case PTRACE_GETFPXREGS: /* Get the child FPU state. */
 235                 ret = get_fpxregs(data, child);
 236                 break;
 237 #endif
 238 #ifdef PTRACE_SETFPXREGS
 239         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 240                 ret = set_fpxregs(data, child);
 241                 break;
 242 #endif
 243         case PTRACE_FAULTINFO: {
 244                 struct ptrace_faultinfo fault;
 245
 246                 fault = ((struct ptrace_faultinfo)
 247                         { .is_write     = child->thread.err,
 248                           .addr         = child->thread.cr2 });
 249                 ret = copy_to_user((unsigned long *) data, &fault,
 250                                    sizeof(fault));
 251                 if(ret)
 252                         break;
 253                 break;
 254         }
 255         case PTRACE_SIGPENDING:
 256                 ret = copy_to_user((unsigned long *) data,
 257                                    &child->pending.signal,
 258                                    sizeof(child->pending.signal));
 259                 break;
 260
 261         case PTRACE_LDT: {
 262                 struct ptrace_ldt ldt;
 263
 264                 if(copy_from_user(&ldt, (unsigned long *) data,
 265                                   sizeof(ldt))){
 266                         ret = -EIO;
 267                         break;
 268                 }
 269
 270                 /* This one is confusing, so just punt and return -EIO for
 271                  * now
 272                  */
 273                 ret = -EIO;
 274                 break;
 275         }
 276 #ifdef CONFIG_PROC_MM
 277         case PTRACE_SWITCH_MM: {
 278                 struct mm_struct *old = child->mm;
 279                 struct mm_struct *new = proc_mm_get_mm(data);
 280
 281                 if(IS_ERR(new)){
 282                         ret = PTR_ERR(new);
 283                         break;
 284                 }
 285
 286                 atomic_inc(&new->mm_users);
 287                 child->mm = new;
 288                 child->active_mm = new;
 289                 mmput(old);
 290                 ret = 0;
 291                 break;
 292         }
 293 #endif
 294         default:
 295                 ret = -EIO;
 296                 break;
 297         }
 298  out_tsk:
 299         put_task_struct(child);
 300  out:
 301         unlock_kernel();
 302         return ret;
 303 }
 304
 305 void syscall_trace(void)
 306 {
 307         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 308                 return;
 309         if (!(current->ptrace & PT_PTRACED))
 310                 return;
 311
 312         /* the 0x80 provides a way for the tracing parent to distinguish
 313            between a syscall stop and SIGTRAP delivery */
 314         current->exit_code = SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 315                                         ? 0x80 : 0);
 316         current->state = TASK_STOPPED;
 317         notify_parent(current, SIGCHLD);
 318         schedule();
 319
 320         /*
 321          * this isn't the same as continuing with a signal, but it will do
 322          * for normal use.  strace only continues with a signal if the
 323          * stopping signal is not SIGTRAP.  -brl
 324          */
 325         if (current->exit_code) {
 326                 send_sig(current->exit_code, current, 1);
 327                 current->exit_code = 0;
 328         }
 329 }
 330
 331 /*
 332  * Overrides for Emacs so that we follow Linus's tabbing style.
 333  * Emacs will notice this stuff at the end of the file and automatically
 334  * adjust the settings for this buffer only.  This must remain at the end
 335  * of the file.
 336  * ---------------------------------------------------------------------------
 337  * Local variables:
 338  * c-file-style: "linux"
 339  * End:
 340  */