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         child->ptrace &= ~PT_DTRACE;
  26         child->thread.singlestep_syscall = 0;
  27 }
  28
  29 long sys_ptrace(long request, long pid, long addr, long data)
  30 {
  31         struct task_struct *child;
  32         int i, ret;
  33
  34         lock_kernel();
  35         ret = -EPERM;
  36         if (request == PTRACE_TRACEME) {
  37                 /* are we already being traced? */
  38                 if (current->ptrace & PT_PTRACED)
  39                         goto out;
  40
  41                 ret = security_ptrace(current->parent, current);
  42                 if (ret)
  43                         goto out;
  44
  45                 /* set the ptrace bit in the process flags. */
  46                 current->ptrace |= PT_PTRACED;
  47                 ret = 0;
  48                 goto out;
  49         }
  50         ret = -ESRCH;
  51         read_lock(&tasklist_lock);
  52         child = find_task_by_pid(pid);
  53         if (child)
  54                 get_task_struct(child);
  55         read_unlock(&tasklist_lock);
  56         if (!child)
  57                 goto out;
  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
 145                 child->ptrace &= ~PT_DTRACE;
 146                 child->thread.singlestep_syscall = 0;
 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->exit_state == EXIT_ZOMBIE)   /* already dead */
 167                         break;
 168
 169                 child->ptrace &= ~PT_DTRACE;
 170                 child->thread.singlestep_syscall = 0;
 171                 child->exit_code = SIGKILL;
 172                 wake_up_process(child);
 173                 break;
 174         }
 175
 176         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 177                 ret = -EIO;
 178                 if ((unsigned long) data > _NSIG)
 179                         break;
 180                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 181                 child->ptrace |= PT_DTRACE;
 182                 child->thread.singlestep_syscall = 0;
 183                 child->exit_code = data;
 184                 /* give it a chance to run. */
 185                 wake_up_process(child);
 186                 ret = 0;
 187                 break;
 188         }
 189
 190         case PTRACE_DETACH:
 191                 /* detach a process that was attached. */
 192                 ret = ptrace_detach(child, data);
 193                 break;
 194
 195 #ifdef PTRACE_GETREGS
 196         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 197                 if (!access_ok(VERIFY_WRITE, (unsigned long *)data,
 198                                FRAME_SIZE_OFFSET)) {
 199                         ret = -EIO;
 200                         break;
 201                 }
 202                 for ( i = 0; i < FRAME_SIZE_OFFSET; i += sizeof(long) ) {
 203                         __put_user(getreg(child, i), (unsigned long *) data);
 204                         data += sizeof(long);
 205                 }
 206                 ret = 0;
 207                 break;
 208         }
 209 #endif
 210 #ifdef PTRACE_SETREGS
 211         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 212                 unsigned long tmp = 0;
 213                 if (!access_ok(VERIFY_READ, (unsigned *)data,
 214                                FRAME_SIZE_OFFSET)) {
 215                         ret = -EIO;
 216                         break;
 217                 }
 218                 for ( i = 0; i < FRAME_SIZE_OFFSET; i += sizeof(long) ) {
 219                         __get_user(tmp, (unsigned long *) data);
 220                         putreg(child, i, tmp);
 221                         data += sizeof(long);
 222                 }
 223                 ret = 0;
 224                 break;
 225         }
 226 #endif
 227 #ifdef PTRACE_GETFPREGS
 228         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 229                 ret = get_fpregs(data, child);
 230                 break;
 231 #endif
 232 #ifdef PTRACE_SETFPREGS
 233         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 234                 ret = set_fpregs(data, child);
 235                 break;
 236 #endif
 237 #ifdef PTRACE_GETFPXREGS
 238         case PTRACE_GETFPXREGS: /* Get the child FPU state. */
 239                 ret = get_fpxregs(data, child);
 240                 break;
 241 #endif
 242 #ifdef PTRACE_SETFPXREGS
 243         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 244                 ret = set_fpxregs(data, child);
 245                 break;
 246 #endif
 247         case PTRACE_FAULTINFO: {
 248                 struct ptrace_faultinfo fault;
 249
 250                 fault = ((struct ptrace_faultinfo)
 251                         { .is_write     = child->thread.err,
 252                           .addr         = child->thread.cr2 });
 253                 ret = copy_to_user((unsigned long *) data, &fault,
 254                                    sizeof(fault));
 255                 if(ret)
 256                         break;
 257                 break;
 258         }
 259         case PTRACE_SIGPENDING:
 260                 ret = copy_to_user((unsigned long *) data,
 261                                    &child->pending.signal,
 262                                    sizeof(child->pending.signal));
 263                 break;
 264
 265         case PTRACE_LDT: {
 266                 struct ptrace_ldt ldt;
 267
 268                 if(copy_from_user(&ldt, (unsigned long *) data,
 269                                   sizeof(ldt))){
 270                         ret = -EIO;
 271                         break;
 272                 }
 273
 274                 /* This one is confusing, so just punt and return -EIO for
 275                  * now
 276                  */
 277                 ret = -EIO;
 278                 break;
 279         }
 280 #ifdef CONFIG_PROC_MM
 281         case PTRACE_SWITCH_MM: {
 282                 struct mm_struct *old = child->mm;
 283                 struct mm_struct *new = proc_mm_get_mm(data);
 284
 285                 if(IS_ERR(new)){
 286                         ret = PTR_ERR(new);
 287                         break;
 288                 }
 289
 290                 atomic_inc(&new->mm_users);
 291                 child->mm = new;
 292                 child->active_mm = new;
 293                 mmput(old);
 294                 ret = 0;
 295                 break;
 296         }
 297 #endif
 298         default:
 299                 ret = ptrace_request(child, request, addr, data);
 300                 break;
 301         }
 302  out_tsk:
 303         put_task_struct(child);
 304  out:
 305         unlock_kernel();
 306         return ret;
 307 }
 308
 309 void syscall_trace(union uml_pt_regs *regs, int entryexit)
 310 {
 311         int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
 312         int tracesysgood;
 313
 314         if (unlikely(current->audit_context)) {
 315                 if (!entryexit)
 316                         audit_syscall_entry(current, regs->orig_eax,
 317                                             regs->ebx, regs->ecx,
 318                                             regs->edx, regs->esi);
 319                 else
 320                         audit_syscall_exit(current, regs->eax);
 321         }
 322
 323         if (!test_thread_flag(TIF_SYSCALL_TRACE) && !is_singlestep)
 324                 return;
 325         if (!(current->ptrace & PT_PTRACED))
 326                 return;
 327
 328         /* the 0x80 provides a way for the tracing parent to distinguish
 329            between a syscall stop and SIGTRAP delivery */
 330         tracesysgood = (current->ptrace & PT_TRACESYSGOOD) && !is_singlestep;
 331         ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
 332
 333         /* force do_signal() --> is_syscall() */
 334         set_thread_flag(TIF_SIGPENDING);
 335
 336         /* this isn't the same as continuing with a signal, but it will do
 337          * for normal use.  strace only continues with a signal if the
 338          * stopping signal is not SIGTRAP.  -brl
 339          */
 340         if (current->exit_code) {
 341                 send_sig(current->exit_code, current, 1);
 342                 current->exit_code = 0;
 343         }
 344 }
 345
 346 /*
 347  * Overrides for Emacs so that we follow Linus's tabbing style.
 348  * Emacs will notice this stuff at the end of the file and automatically
 349  * adjust the settings for this buffer only.  This must remain at the end
 350  * of the file.
 351  * ---------------------------------------------------------------------------
 352  * Local variables:
 353  * c-file-style: "linux"
 354  * End:
 355  */