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                 else if((addr >= offsetof(struct user, u_debugreg[0])) &&
 102                         (addr <= offsetof(struct user, u_debugreg[7]))){
 103                         addr -= offsetof(struct user, u_debugreg[0]);
 104                         addr = addr >> 2;
 105                         tmp = child->thread.arch.debugregs[addr];
 106                 }
 107                 ret = put_user(tmp, (unsigned long __user *) data);
 108                 break;
 109         }
 110
 111         /* when I and D space are separate, this will have to be fixed. */
 112         case PTRACE_POKETEXT: /* write the word at location addr. */
 113         case PTRACE_POKEDATA:
 114                 ret = -EIO;
 115                 if (access_process_vm(child, addr, &data, sizeof(data),
 116                                       1) != sizeof(data))
 117                         break;
 118                 ret = 0;
 119                 break;
 120
 121         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 122                 ret = -EIO;
 123                 if ((addr & 3) || addr < 0)
 124                         break;
 125
 126                 if (addr < MAX_REG_OFFSET) {
 127                         ret = putreg(child, addr, data);
 128                         break;
 129                 }
 130 #if 0 /* XXX x86_64 */
 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 #endif
 140
 141                 break;
 142
 143         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 144         case PTRACE_CONT: { /* restart after signal. */
 145                 ret = -EIO;
 146                 if ((unsigned long) data > _NSIG)
 147                         break;
 148
 149                 child->ptrace &= ~PT_DTRACE;
 150                 child->thread.singlestep_syscall = 0;
 151                 if (request == PTRACE_SYSCALL) {
 152                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 153                 }
 154                 else {
 155                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 156                 }
 157                 child->exit_code = data;
 158                 wake_up_process(child);
 159                 ret = 0;
 160                 break;
 161         }
 162
 163 /*
 164  * make the child exit.  Best I can do is send it a sigkill.
 165  * perhaps it should be put in the status that it wants to
 166  * exit.
 167  */
 168         case PTRACE_KILL: {
 169                 ret = 0;
 170                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 171                         break;
 172
 173                 child->ptrace &= ~PT_DTRACE;
 174                 child->thread.singlestep_syscall = 0;
 175                 child->exit_code = SIGKILL;
 176                 wake_up_process(child);
 177                 break;
 178         }
 179
 180         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 181                 ret = -EIO;
 182                 if ((unsigned long) data > _NSIG)
 183                         break;
 184                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 185                 child->ptrace |= PT_DTRACE;
 186                 child->thread.singlestep_syscall = 0;
 187                 child->exit_code = data;
 188                 /* give it a chance to run. */
 189                 wake_up_process(child);
 190                 ret = 0;
 191                 break;
 192         }
 193
 194         case PTRACE_DETACH:
 195                 /* detach a process that was attached. */
 196                 ret = ptrace_detach(child, data);
 197                 break;
 198
 199 #ifdef PTRACE_GETREGS
 200         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 201                 if (!access_ok(VERIFY_WRITE, (unsigned long *)data,
 202                                MAX_REG_OFFSET)) {
 203                         ret = -EIO;
 204                         break;
 205                 }
 206                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 207                         __put_user(getreg(child, i),
 208                                    (unsigned long __user *) data);
 209                         data += sizeof(long);
 210                 }
 211                 ret = 0;
 212                 break;
 213         }
 214 #endif
 215 #ifdef PTRACE_SETREGS
 216         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 217                 unsigned long tmp = 0;
 218                 if (!access_ok(VERIFY_READ, (unsigned *)data,
 219                                MAX_REG_OFFSET)) {
 220                         ret = -EIO;
 221                         break;
 222                 }
 223                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 224                         __get_user(tmp, (unsigned long __user *) data);
 225                         putreg(child, i, tmp);
 226                         data += sizeof(long);
 227                 }
 228                 ret = 0;
 229                 break;
 230         }
 231 #endif
 232 #ifdef PTRACE_GETFPREGS
 233         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 234                 ret = get_fpregs(data, child);
 235                 break;
 236 #endif
 237 #ifdef PTRACE_SETFPREGS
 238         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 239                 ret = set_fpregs(data, child);
 240                 break;
 241 #endif
 242 #ifdef PTRACE_GETFPXREGS
 243         case PTRACE_GETFPXREGS: /* Get the child FPU state. */
 244                 ret = get_fpxregs(data, child);
 245                 break;
 246 #endif
 247 #ifdef PTRACE_SETFPXREGS
 248         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 249                 ret = set_fpxregs(data, child);
 250                 break;
 251 #endif
 252         case PTRACE_FAULTINFO: {
 253                 struct ptrace_faultinfo fault;
 254
 255                 fault = ((struct ptrace_faultinfo)
 256                         { .is_write     = child->thread.err,
 257                           .addr         = child->thread.cr2 });
 258                 ret = copy_to_user((unsigned long __user *) data, &fault,
 259                                    sizeof(fault));
 260                 if(ret)
 261                         break;
 262                 break;
 263         }
 264         case PTRACE_SIGPENDING:
 265                 ret = copy_to_user((unsigned long __user *) data,
 266                                    &child->pending.signal,
 267                                    sizeof(child->pending.signal));
 268                 break;
 269
 270         case PTRACE_LDT: {
 271                 struct ptrace_ldt ldt;
 272
 273                 if(copy_from_user(&ldt, (unsigned long __user *) data,
 274                                   sizeof(ldt))){
 275                         ret = -EIO;
 276                         break;
 277                 }
 278
 279                 /* This one is confusing, so just punt and return -EIO for
 280                  * now
 281                  */
 282                 ret = -EIO;
 283                 break;
 284         }
 285 #ifdef CONFIG_PROC_MM
 286         case PTRACE_SWITCH_MM: {
 287                 struct mm_struct *old = child->mm;
 288                 struct mm_struct *new = proc_mm_get_mm(data);
 289
 290                 if(IS_ERR(new)){
 291                         ret = PTR_ERR(new);
 292                         break;
 293                 }
 294
 295                 atomic_inc(&new->mm_users);
 296                 child->mm = new;
 297                 child->active_mm = new;
 298                 mmput(old);
 299                 ret = 0;
 300                 break;
 301         }
 302 #endif
 303         default:
 304                 ret = ptrace_request(child, request, addr, data);
 305                 break;
 306         }
 307  out_tsk:
 308         put_task_struct(child);
 309  out:
 310         unlock_kernel();
 311         return ret;
 312 }
 313
 314 void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
 315                   int error_code)
 316 {
 317         struct siginfo info;
 318
 319         memset(&info, 0, sizeof(info));
 320         info.si_signo = SIGTRAP;
 321         info.si_code = TRAP_BRKPT;
 322
 323         /* User-mode eip? */
 324         info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
 325
 326         /* Send us the fakey SIGTRAP */
 327         force_sig_info(SIGTRAP, &info, tsk);
 328 }
 329
 330 /* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
 331  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
 332  */
 333 void syscall_trace(union uml_pt_regs *regs, int entryexit)
 334 {
 335         int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
 336         int tracesysgood;
 337
 338         if (unlikely(current->audit_context)) {
 339                 if (!entryexit)
 340                         audit_syscall_entry(current,
 341                                             UPT_SYSCALL_NR(&regs->regs),
 342                                             UPT_SYSCALL_ARG1(&regs->regs),
 343                                             UPT_SYSCALL_ARG2(&regs->regs),
 344                                             UPT_SYSCALL_ARG3(&regs->regs),
 345                                             UPT_SYSCALL_ARG4(&regs->regs));
 346                 else
 347                         audit_syscall_exit(current,
 348                                            UPT_SYSCALL_RET(&regs->regs));
 349         }
 350
 351         /* Fake a debug trap */
 352         if (is_singlestep)
 353                 send_sigtrap(current, regs, 0);
 354
 355         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 356                 return;
 357
 358         if (!(current->ptrace & PT_PTRACED))
 359                 return;
 360
 361         /* the 0x80 provides a way for the tracing parent to distinguish
 362            between a syscall stop and SIGTRAP delivery */
 363         tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
 364         ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
 365
 366         if (entryexit) /* force do_signal() --> is_syscall() */
 367                 set_thread_flag(TIF_SIGPENDING);
 368
 369         /* this isn't the same as continuing with a signal, but it will do
 370          * for normal use.  strace only continues with a signal if the
 371          * stopping signal is not SIGTRAP.  -brl
 372          */
 373         if (current->exit_code) {
 374                 send_sig(current->exit_code, current, 1);
 375                 current->exit_code = 0;
 376         }
 377 }
 378
 379 /*
 380  * Overrides for Emacs so that we follow Linus's tabbing style.
 381  * Emacs will notice this stuff at the end of the file and automatically
 382  * adjust the settings for this buffer only.  This must remain at the end
 383  * of the file.
 384  * ---------------------------------------------------------------------------
 385  * Local variables:
 386  * c-file-style: "linux"
 387  * End:
 388  */