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 int sys_ptrace(long request, long pid, long addr, long data)
  28 {
  29         struct task_struct *child;
  30         int i, ret;
  31
  32         lock_kernel();
  33         ret = -EPERM;
  34         if (request == PTRACE_TRACEME) {
  35                 /* are we already being traced? */
  36                 if (current->ptrace & PT_PTRACED)
  37                         goto out;
  38
  39                 ret = security_ptrace(current->parent, current);
  40                 if (ret)
  41                         goto out;
  42
  43                 /* set the ptrace bit in the process flags. */
  44                 current->ptrace |= PT_PTRACED;
  45                 ret = 0;
  46                 goto out;
  47         }
  48         ret = -ESRCH;
  49         read_lock(&tasklist_lock);
  50         child = find_task_by_pid(pid);
  51         if (child)
  52                 get_task_struct(child);
  53         read_unlock(&tasklist_lock);
  54         if (!child)
  55                 goto out;
  56         if (!vx_check(vx_task_xid(child), VX_WATCH|VX_IDENT))
  57                 goto out_tsk;
  58
  59         ret = -EPERM;
  60         if (pid == 1)           /* you may not mess with init */
  61                 goto out_tsk;
  62
  63         if (request == PTRACE_ATTACH) {
  64                 ret = ptrace_attach(child);
  65                 goto out_tsk;
  66         }
  67
  68         ret = ptrace_check_attach(child, request == PTRACE_KILL);
  69         if (ret < 0)
  70                 goto out_tsk;
  71
  72         switch (request) {
  73                 /* when I and D space are separate, these will need to be fixed. */
  74         case PTRACE_PEEKTEXT: /* read word at location addr. */
  75         case PTRACE_PEEKDATA: {
  76                 unsigned long tmp;
  77                 int copied;
  78
  79                 ret = -EIO;
  80                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
  81                 if (copied != sizeof(tmp))
  82                         break;
  83                 ret = put_user(tmp,(unsigned long *) data);
  84                 break;
  85         }
  86
  87         /* read the word at location addr in the USER area. */
  88         case PTRACE_PEEKUSR: {
  89                 unsigned long tmp;
  90
  91                 ret = -EIO;
  92                 if ((addr & 3) || addr < 0)
  93                         break;
  94
  95                 tmp = 0;  /* Default return condition */
  96                 if(addr < FRAME_SIZE_OFFSET){
  97                         tmp = getreg(child, addr);
  98                 }
  99                 else if((addr >= offsetof(struct user, u_debugreg[0])) &&
 100                         (addr <= offsetof(struct user, u_debugreg[7]))){
 101                         addr -= offsetof(struct user, u_debugreg[0]);
 102                         addr = addr >> 2;
 103                         tmp = child->thread.arch.debugregs[addr];
 104                 }
 105                 ret = put_user(tmp, (unsigned long *) data);
 106                 break;
 107         }
 108
 109         /* when I and D space are separate, this will have to be fixed. */
 110         case PTRACE_POKETEXT: /* write the word at location addr. */
 111         case PTRACE_POKEDATA:
 112                 ret = -EIO;
 113                 if (access_process_vm(child, addr, &data, sizeof(data),
 114                                       1) != sizeof(data))
 115                         break;
 116                 ret = 0;
 117                 break;
 118
 119         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 120                 ret = -EIO;
 121                 if ((addr & 3) || addr < 0)
 122                         break;
 123
 124                 if (addr < FRAME_SIZE_OFFSET) {
 125                         ret = putreg(child, addr, data);
 126                         break;
 127                 }
 128                 else if((addr >= offsetof(struct user, u_debugreg[0])) &&
 129                         (addr <= offsetof(struct user, u_debugreg[7]))){
 130                           addr -= offsetof(struct user, u_debugreg[0]);
 131                           addr = addr >> 2;
 132                           if((addr == 4) || (addr == 5)) break;
 133                           child->thread.arch.debugregs[addr] = data;
 134                           ret = 0;
 135                 }
 136
 137                 break;
 138
 139         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 140         case PTRACE_CONT: { /* restart after signal. */
 141                 ret = -EIO;
 142                 if ((unsigned long) data > _NSIG)
 143                         break;
 144                 if (request == PTRACE_SYSCALL) {
 145                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 146                 }
 147                 else {
 148                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 149                 }
 150                 child->exit_code = data;
 151                 wake_up_process(child);
 152                 ret = 0;
 153                 break;
 154         }
 155
 156 /*
 157  * make the child exit.  Best I can do is send it a sigkill.
 158  * perhaps it should be put in the status that it wants to
 159  * exit.
 160  */
 161         case PTRACE_KILL: {
 162                 ret = 0;
 163                 if (child->state == TASK_ZOMBIE)        /* already dead */
 164                         break;
 165                 child->exit_code = SIGKILL;
 166                 wake_up_process(child);
 167                 break;
 168         }
 169
 170         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 171                 ret = -EIO;
 172                 if ((unsigned long) data > _NSIG)
 173                         break;
 174                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 175                 child->ptrace |= PT_DTRACE;
 176                 child->exit_code = data;
 177                 /* give it a chance to run. */
 178                 wake_up_process(child);
 179                 ret = 0;
 180                 break;
 181         }
 182
 183         case PTRACE_DETACH:
 184                 /* detach a process that was attached. */
 185                 ret = ptrace_detach(child, data);
 186                 break;
 187
 188 #ifdef PTRACE_GETREGS
 189         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 190                 if (!access_ok(VERIFY_WRITE, (unsigned long *)data,
 191                                FRAME_SIZE_OFFSET)) {
 192                         ret = -EIO;
 193                         break;
 194                 }
 195                 for ( i = 0; i < FRAME_SIZE_OFFSET; i += sizeof(long) ) {
 196                         __put_user(getreg(child, i), (unsigned long *) data);
 197                         data += sizeof(long);
 198                 }
 199                 ret = 0;
 200                 break;
 201         }
 202 #endif
 203 #ifdef PTRACE_SETREGS
 204         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 205                 unsigned long tmp = 0;
 206                 if (!access_ok(VERIFY_READ, (unsigned *)data,
 207                                FRAME_SIZE_OFFSET)) {
 208                         ret = -EIO;
 209                         break;
 210                 }
 211                 for ( i = 0; i < FRAME_SIZE_OFFSET; i += sizeof(long) ) {
 212                         __get_user(tmp, (unsigned long *) data);
 213                         putreg(child, i, tmp);
 214                         data += sizeof(long);
 215                 }
 216                 ret = 0;
 217                 break;
 218         }
 219 #endif
 220 #ifdef PTRACE_GETFPREGS
 221         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 222                 ret = get_fpregs(data, child);
 223                 break;
 224 #endif
 225 #ifdef PTRACE_SETFPREGS
 226         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 227                 ret = set_fpregs(data, child);
 228                 break;
 229 #endif
 230 #ifdef PTRACE_GETFPXREGS
 231         case PTRACE_GETFPXREGS: /* Get the child FPU state. */
 232                 ret = get_fpxregs(data, child);
 233                 break;
 234 #endif
 235 #ifdef PTRACE_SETFPXREGS
 236         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 237                 ret = set_fpxregs(data, child);
 238                 break;
 239 #endif
 240         case PTRACE_FAULTINFO: {
 241                 struct ptrace_faultinfo fault;
 242
 243                 fault = ((struct ptrace_faultinfo)
 244                         { .is_write     = child->thread.err,
 245                           .addr         = child->thread.cr2 });
 246                 ret = copy_to_user((unsigned long *) data, &fault,
 247                                    sizeof(fault));
 248                 if(ret)
 249                         break;
 250                 break;
 251         }
 252         case PTRACE_SIGPENDING:
 253                 ret = copy_to_user((unsigned long *) data,
 254                                    &child->pending.signal,
 255                                    sizeof(child->pending.signal));
 256                 break;
 257
 258         case PTRACE_LDT: {
 259                 struct ptrace_ldt ldt;
 260
 261                 if(copy_from_user(&ldt, (unsigned long *) data,
 262                                   sizeof(ldt))){
 263                         ret = -EIO;
 264                         break;
 265                 }
 266
 267                 /* This one is confusing, so just punt and return -EIO for
 268                  * now
 269                  */
 270                 ret = -EIO;
 271                 break;
 272         }
 273 #ifdef CONFIG_PROC_MM
 274         case PTRACE_SWITCH_MM: {
 275                 struct mm_struct *old = child->mm;
 276                 struct mm_struct *new = proc_mm_get_mm(data);
 277
 278                 if(IS_ERR(new)){
 279                         ret = PTR_ERR(new);
 280                         break;
 281                 }
 282
 283                 atomic_inc(&new->mm_users);
 284                 child->mm = new;
 285                 child->active_mm = new;
 286                 mmput(old);
 287                 ret = 0;
 288                 break;
 289         }
 290 #endif
 291         default:
 292                 ret = ptrace_request(child, request, addr, data);
 293                 break;
 294         }
 295  out_tsk:
 296         put_task_struct(child);
 297  out:
 298         unlock_kernel();
 299         return ret;
 300 }
 301
 302 void syscall_trace(union uml_pt_regs *regs, int entryexit)
 303 {
 304         if (unlikely(current->audit_context)) {
 305                 if (!entryexit)
 306                         audit_syscall_entry(current, regs->orig_eax,
 307                                             regs->ebx, regs->ecx,
 308                                             regs->edx, regs->esi);
 309                 else
 310                         audit_syscall_exit(current, regs->eax);
 311         }
 312
 313         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 314                 return;
 315         if (!(current->ptrace & PT_PTRACED))
 316                 return;
 317
 318         /* the 0x80 provides a way for the tracing parent to distinguish
 319            between a syscall stop and SIGTRAP delivery */
 320         ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD)
 321                                  ? 0x80 : 0));
 322
 323         /*
 324          * this isn't the same as continuing with a signal, but it will do
 325          * for normal use.  strace only continues with a signal if the
 326          * stopping signal is not SIGTRAP.  -brl
 327          */
 328         if (current->exit_code) {
 329                 send_sig(current->exit_code, current, 1);
 330                 current->exit_code = 0;
 331         }
 332 }
 333
 334 /*
 335  * Overrides for Emacs so that we follow Linus's tabbing style.
 336  * Emacs will notice this stuff at the end of the file and automatically
 337  * adjust the settings for this buffer only.  This must remain at the end
 338  * of the file.
 339  * ---------------------------------------------------------------------------
 340  * Local variables:
 341  * c-file-style: "linux"
 342  * End:
 343  */