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 #include "linux/audit.h"
  13 #ifdef CONFIG_PROC_MM
  14 #include "linux/proc_mm.h"
  15 #endif
  16 #include "asm/ptrace.h"
  17 #include "asm/uaccess.h"
  18 #include "kern_util.h"
  19 #include "skas_ptrace.h"
  20 #include "sysdep/ptrace.h"
  21
  22 /*
  23  * Called by kernel/ptrace.c when detaching..
  24  */
  25 void ptrace_disable(struct task_struct *child)
  26 {
  27         child->ptrace &= ~PT_DTRACE;
  28         child->thread.singlestep_syscall = 0;
  29 }
  30
  31 long sys_ptrace(long request, long pid, long addr, long data)
  32 {
  33         struct task_struct *child;
  34         int i, ret;
  35
  36         lock_kernel();
  37         ret = -EPERM;
  38         if (request == PTRACE_TRACEME) {
  39                 /* are we already being traced? */
  40                 if (current->ptrace & PT_PTRACED)
  41                         goto out;
  42
  43                 ret = security_ptrace(current->parent, current);
  44                 if (ret)
  45                         goto out;
  46
  47                 /* set the ptrace bit in the process flags. */
  48                 current->ptrace |= PT_PTRACED;
  49                 ret = 0;
  50                 goto out;
  51         }
  52         ret = -ESRCH;
  53         read_lock(&tasklist_lock);
  54         child = find_task_by_pid(pid);
  55         if (child)
  56                 get_task_struct(child);
  57         read_unlock(&tasklist_lock);
  58         if (!child)
  59                 goto out;
  60
  61         ret = -EPERM;
  62         if (pid == 1)           /* you may not mess with init */
  63                 goto out_tsk;
  64
  65         if (request == PTRACE_ATTACH) {
  66                 ret = ptrace_attach(child);
  67                 goto out_tsk;
  68         }
  69
  70         ret = ptrace_check_attach(child, request == PTRACE_KILL);
  71         if (ret < 0)
  72                 goto out_tsk;
  73
  74         switch (request) {
  75                 /* when I and D space are separate, these will need to be fixed. */
  76         case PTRACE_PEEKTEXT: /* read word at location addr. */
  77         case PTRACE_PEEKDATA: {
  78                 unsigned long tmp;
  79                 int copied;
  80
  81                 ret = -EIO;
  82                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
  83                 if (copied != sizeof(tmp))
  84                         break;
  85                 ret = put_user(tmp, (unsigned long __user *) data);
  86                 break;
  87         }
  88
  89         /* read the word at location addr in the USER area. */
  90         case PTRACE_PEEKUSR: {
  91                 unsigned long tmp;
  92
  93                 ret = -EIO;
  94                 if ((addr & 3) || addr < 0)
  95                         break;
  96
  97                 tmp = 0;  /* Default return condition */
  98                 if(addr < MAX_REG_OFFSET){
  99                         tmp = getreg(child, addr);
 100                 }
 101 #if defined(CONFIG_UML_X86) && !defined(CONFIG_64BIT)
 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 #endif
 109                 ret = put_user(tmp, (unsigned long __user *) data);
 110                 break;
 111         }
 112
 113         /* when I and D space are separate, this will have to be fixed. */
 114         case PTRACE_POKETEXT: /* write the word at location addr. */
 115         case PTRACE_POKEDATA:
 116                 ret = -EIO;
 117                 if (access_process_vm(child, addr, &data, sizeof(data),
 118                                       1) != sizeof(data))
 119                         break;
 120                 ret = 0;
 121                 break;
 122
 123         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 124                 ret = -EIO;
 125                 if ((addr & 3) || addr < 0)
 126                         break;
 127
 128                 if (addr < MAX_REG_OFFSET) {
 129                         ret = putreg(child, addr, data);
 130                         break;
 131                 }
 132 #if defined(CONFIG_UML_X86) && !defined(CONFIG_64BIT)
 133                 else if((addr >= offsetof(struct user, u_debugreg[0])) &&
 134                         (addr <= offsetof(struct user, u_debugreg[7]))){
 135                           addr -= offsetof(struct user, u_debugreg[0]);
 136                           addr = addr >> 2;
 137                           if((addr == 4) || (addr == 5)) break;
 138                           child->thread.arch.debugregs[addr] = data;
 139                           ret = 0;
 140                 }
 141 #endif
 142
 143                 break;
 144
 145         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 146         case PTRACE_CONT: { /* restart after signal. */
 147                 ret = -EIO;
 148                 if (!valid_signal(data))
 149                         break;
 150
 151                 child->ptrace &= ~PT_DTRACE;
 152                 child->thread.singlestep_syscall = 0;
 153                 if (request == PTRACE_SYSCALL) {
 154                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 155                 }
 156                 else {
 157                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 158                 }
 159                 child->exit_code = data;
 160                 wake_up_process(child);
 161                 ret = 0;
 162                 break;
 163         }
 164
 165 /*
 166  * make the child exit.  Best I can do is send it a sigkill.
 167  * perhaps it should be put in the status that it wants to
 168  * exit.
 169  */
 170         case PTRACE_KILL: {
 171                 ret = 0;
 172                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 173                         break;
 174
 175                 child->ptrace &= ~PT_DTRACE;
 176                 child->thread.singlestep_syscall = 0;
 177                 child->exit_code = SIGKILL;
 178                 wake_up_process(child);
 179                 break;
 180         }
 181
 182         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 183                 ret = -EIO;
 184                 if (!valid_signal(data))
 185                         break;
 186                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 187                 child->ptrace |= PT_DTRACE;
 188                 child->thread.singlestep_syscall = 0;
 189                 child->exit_code = data;
 190                 /* give it a chance to run. */
 191                 wake_up_process(child);
 192                 ret = 0;
 193                 break;
 194         }
 195
 196         case PTRACE_DETACH:
 197                 /* detach a process that was attached. */
 198                 ret = ptrace_detach(child, data);
 199                 break;
 200
 201 #ifdef PTRACE_GETREGS
 202         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 203                 if (!access_ok(VERIFY_WRITE, (unsigned long *)data,
 204                                MAX_REG_OFFSET)) {
 205                         ret = -EIO;
 206                         break;
 207                 }
 208                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 209                         __put_user(getreg(child, i),
 210                                    (unsigned long __user *) data);
 211                         data += sizeof(long);
 212                 }
 213                 ret = 0;
 214                 break;
 215         }
 216 #endif
 217 #ifdef PTRACE_SETREGS
 218         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 219                 unsigned long tmp = 0;
 220                 if (!access_ok(VERIFY_READ, (unsigned *)data,
 221                                MAX_REG_OFFSET)) {
 222                         ret = -EIO;
 223                         break;
 224                 }
 225                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 226                         __get_user(tmp, (unsigned long __user *) data);
 227                         putreg(child, i, tmp);
 228                         data += sizeof(long);
 229                 }
 230                 ret = 0;
 231                 break;
 232         }
 233 #endif
 234 #ifdef PTRACE_GETFPREGS
 235         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 236                 ret = get_fpregs(data, child);
 237                 break;
 238 #endif
 239 #ifdef PTRACE_SETFPREGS
 240         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 241                 ret = set_fpregs(data, child);
 242                 break;
 243 #endif
 244 #ifdef PTRACE_GETFPXREGS
 245         case PTRACE_GETFPXREGS: /* Get the child FPU state. */
 246                 ret = get_fpxregs(data, child);
 247                 break;
 248 #endif
 249 #ifdef PTRACE_SETFPXREGS
 250         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 251                 ret = set_fpxregs(data, child);
 252                 break;
 253 #endif
 254         case PTRACE_FAULTINFO: {
 255                 /* Take the info from thread->arch->faultinfo,
 256                  * but transfer max. sizeof(struct ptrace_faultinfo).
 257                  * On i386, ptrace_faultinfo is smaller!
 258                  */
 259                 ret = copy_to_user((unsigned long __user *) data,
 260                                    &child->thread.arch.faultinfo,
 261                                    sizeof(struct ptrace_faultinfo));
 262                 if(ret)
 263                         break;
 264                 break;
 265         }
 266         case PTRACE_SIGPENDING:
 267                 ret = copy_to_user((unsigned long __user *) data,
 268                                    &child->pending.signal,
 269                                    sizeof(child->pending.signal));
 270                 break;
 271
 272 #ifdef PTRACE_LDT
 273         case PTRACE_LDT: {
 274                 struct ptrace_ldt ldt;
 275
 276                 if(copy_from_user(&ldt, (unsigned long __user *) data,
 277                                   sizeof(ldt))){
 278                         ret = -EIO;
 279                         break;
 280                 }
 281
 282                 /* This one is confusing, so just punt and return -EIO for
 283                  * now
 284                  */
 285                 ret = -EIO;
 286                 break;
 287         }
 288 #endif
 289 #ifdef CONFIG_PROC_MM
 290         case PTRACE_SWITCH_MM: {
 291                 struct mm_struct *old = child->mm;
 292                 struct mm_struct *new = proc_mm_get_mm(data);
 293
 294                 if(IS_ERR(new)){
 295                         ret = PTR_ERR(new);
 296                         break;
 297                 }
 298
 299                 atomic_inc(&new->mm_users);
 300                 child->mm = new;
 301                 child->active_mm = new;
 302                 mmput(old);
 303                 ret = 0;
 304                 break;
 305         }
 306 #endif
 307         default:
 308                 ret = ptrace_request(child, request, addr, data);
 309                 break;
 310         }
 311  out_tsk:
 312         put_task_struct(child);
 313  out:
 314         unlock_kernel();
 315         return ret;
 316 }
 317
 318 void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
 319                   int error_code)
 320 {
 321         struct siginfo info;
 322
 323         memset(&info, 0, sizeof(info));
 324         info.si_signo = SIGTRAP;
 325         info.si_code = TRAP_BRKPT;
 326
 327         /* User-mode eip? */
 328         info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
 329
 330         /* Send us the fakey SIGTRAP */
 331         force_sig_info(SIGTRAP, &info, tsk);
 332 }
 333
 334 /* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
 335  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
 336  */
 337 void syscall_trace(union uml_pt_regs *regs, int entryexit)
 338 {
 339         int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
 340         int tracesysgood;
 341
 342         if (unlikely(current->audit_context)) {
 343                 if (!entryexit)
 344                         audit_syscall_entry(current,
 345                                             HOST_AUDIT_ARCH,
 346                                             UPT_SYSCALL_NR(regs),
 347                                             UPT_SYSCALL_ARG1(regs),
 348                                             UPT_SYSCALL_ARG2(regs),
 349                                             UPT_SYSCALL_ARG3(regs),
 350                                             UPT_SYSCALL_ARG4(regs));
 351                 else {
 352                         int res = UPT_SYSCALL_RET(regs);
 353                         audit_syscall_exit(current, AUDITSC_RESULT(res),
 354                                            res);
 355                 }
 356         }
 357
 358         /* Fake a debug trap */
 359         if (is_singlestep)
 360                 send_sigtrap(current, regs, 0);
 361
 362         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 363                 return;
 364
 365         if (!(current->ptrace & PT_PTRACED))
 366                 return;
 367
 368         /* the 0x80 provides a way for the tracing parent to distinguish
 369            between a syscall stop and SIGTRAP delivery */
 370         tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
 371         ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
 372
 373         if (entryexit) /* force do_signal() --> is_syscall() */
 374                 set_thread_flag(TIF_SIGPENDING);
 375
 376         /* this isn't the same as continuing with a signal, but it will do
 377          * for normal use.  strace only continues with a signal if the
 378          * stopping signal is not SIGTRAP.  -brl
 379          */
 380         if (current->exit_code) {
 381                 send_sig(current->exit_code, current, 1);
 382                 current->exit_code = 0;
 383         }
 384 }
 385
 386 /*
 387  * Overrides for Emacs so that we follow Linus's tabbing style.
 388  * Emacs will notice this stuff at the end of the file and automatically
 389  * adjust the settings for this buffer only.  This must remain at the end
 390  * of the file.
 391  * ---------------------------------------------------------------------------
 392  * Local variables:
 393  * c-file-style: "linux"
 394  * End:
 395  */