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 #include "skas_ptrace.h"
  20
  21 /*
  22  * Called by kernel/ptrace.c when detaching..
  23  */
  24 void ptrace_disable(struct task_struct *child)
  25 {
  26         child->ptrace &= ~PT_DTRACE;
  27         child->thread.singlestep_syscall = 0;
  28 }
  29
  30 long sys_ptrace(long request, long pid, long addr, long data)
  31 {
  32         struct task_struct *child;
  33         int i, ret;
  34
  35         lock_kernel();
  36         ret = -EPERM;
  37         if (request == PTRACE_TRACEME) {
  38                 /* are we already being traced? */
  39                 if (current->ptrace & PT_PTRACED)
  40                         goto out;
  41
  42                 ret = security_ptrace(current->parent, current);
  43                 if (ret)
  44                         goto out;
  45
  46                 /* set the ptrace bit in the process flags. */
  47                 current->ptrace |= PT_PTRACED;
  48                 ret = 0;
  49                 goto out;
  50         }
  51         ret = -ESRCH;
  52         read_lock(&tasklist_lock);
  53         child = find_task_by_pid(pid);
  54         if (child)
  55                 get_task_struct(child);
  56         read_unlock(&tasklist_lock);
  57         if (!child)
  58                 goto out;
  59         if (!vx_check(vx_task_xid(child), VX_WATCH|VX_IDENT))
  60                 goto out_tsk;
  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 __user *) 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 < MAX_REG_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 __user *) 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 < MAX_REG_OFFSET) {
 128                         ret = putreg(child, addr, data);
 129                         break;
 130                 }
 131 #if 0 /* XXX x86_64 */
 132                 else if((addr >= offsetof(struct user, u_debugreg[0])) &&
 133                         (addr <= offsetof(struct user, u_debugreg[7]))){
 134                           addr -= offsetof(struct user, u_debugreg[0]);
 135                           addr = addr >> 2;
 136                           if((addr == 4) || (addr == 5)) break;
 137                           child->thread.arch.debugregs[addr] = data;
 138                           ret = 0;
 139                 }
 140 #endif
 141
 142                 break;
 143
 144         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 145         case PTRACE_CONT: { /* restart after signal. */
 146                 ret = -EIO;
 147                 if ((unsigned long) data > _NSIG)
 148                         break;
 149
 150                 child->ptrace &= ~PT_DTRACE;
 151                 child->thread.singlestep_syscall = 0;
 152                 if (request == PTRACE_SYSCALL) {
 153                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 154                 }
 155                 else {
 156                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 157                 }
 158                 child->exit_code = data;
 159                 wake_up_process(child);
 160                 ret = 0;
 161                 break;
 162         }
 163
 164 /*
 165  * make the child exit.  Best I can do is send it a sigkill.
 166  * perhaps it should be put in the status that it wants to
 167  * exit.
 168  */
 169         case PTRACE_KILL: {
 170                 ret = 0;
 171                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 172                         break;
 173
 174                 child->ptrace &= ~PT_DTRACE;
 175                 child->thread.singlestep_syscall = 0;
 176                 child->exit_code = SIGKILL;
 177                 wake_up_process(child);
 178                 break;
 179         }
 180
 181         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 182                 ret = -EIO;
 183                 if ((unsigned long) data > _NSIG)
 184                         break;
 185                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 186                 child->ptrace |= PT_DTRACE;
 187                 child->thread.singlestep_syscall = 0;
 188                 child->exit_code = data;
 189                 /* give it a chance to run. */
 190                 wake_up_process(child);
 191                 ret = 0;
 192                 break;
 193         }
 194
 195         case PTRACE_DETACH:
 196                 /* detach a process that was attached. */
 197                 ret = ptrace_detach(child, data);
 198                 break;
 199
 200 #ifdef PTRACE_GETREGS
 201         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 202                 if (!access_ok(VERIFY_WRITE, (unsigned long *)data,
 203                                MAX_REG_OFFSET)) {
 204                         ret = -EIO;
 205                         break;
 206                 }
 207                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 208                         __put_user(getreg(child, i),
 209                                    (unsigned long __user *) data);
 210                         data += sizeof(long);
 211                 }
 212                 ret = 0;
 213                 break;
 214         }
 215 #endif
 216 #ifdef PTRACE_SETREGS
 217         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 218                 unsigned long tmp = 0;
 219                 if (!access_ok(VERIFY_READ, (unsigned *)data,
 220                                MAX_REG_OFFSET)) {
 221                         ret = -EIO;
 222                         break;
 223                 }
 224                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 225                         __get_user(tmp, (unsigned long __user *) data);
 226                         putreg(child, i, tmp);
 227                         data += sizeof(long);
 228                 }
 229                 ret = 0;
 230                 break;
 231         }
 232 #endif
 233 #ifdef PTRACE_GETFPREGS
 234         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 235                 ret = get_fpregs(data, child);
 236                 break;
 237 #endif
 238 #ifdef PTRACE_SETFPREGS
 239         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 240                 ret = set_fpregs(data, child);
 241                 break;
 242 #endif
 243 #ifdef PTRACE_GETFPXREGS
 244         case PTRACE_GETFPXREGS: /* Get the child FPU state. */
 245                 ret = get_fpxregs(data, child);
 246                 break;
 247 #endif
 248 #ifdef PTRACE_SETFPXREGS
 249         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 250                 ret = set_fpxregs(data, child);
 251                 break;
 252 #endif
 253         case PTRACE_FAULTINFO: {
 254                 struct ptrace_faultinfo fault;
 255
 256                 fault = ((struct ptrace_faultinfo)
 257                         { .is_write     = child->thread.err,
 258                           .addr         = child->thread.cr2 });
 259                 ret = copy_to_user((unsigned long __user *) data, &fault,
 260                                    sizeof(fault));
 261                 if(ret)
 262                         break;
 263                 break;
 264         }
 265         case PTRACE_SIGPENDING:
 266                 ret = copy_to_user((unsigned long __user *) data,
 267                                    &child->pending.signal,
 268                                    sizeof(child->pending.signal));
 269                 break;
 270
 271         case PTRACE_LDT: {
 272                 struct ptrace_ldt ldt;
 273
 274                 if(copy_from_user(&ldt, (unsigned long __user *) data,
 275                                   sizeof(ldt))){
 276                         ret = -EIO;
 277                         break;
 278                 }
 279
 280                 /* This one is confusing, so just punt and return -EIO for
 281                  * now
 282                  */
 283                 ret = -EIO;
 284                 break;
 285         }
 286 #ifdef CONFIG_PROC_MM
 287         case PTRACE_SWITCH_MM: {
 288                 struct mm_struct *old = child->mm;
 289                 struct mm_struct *new = proc_mm_get_mm(data);
 290
 291                 if(IS_ERR(new)){
 292                         ret = PTR_ERR(new);
 293                         break;
 294                 }
 295
 296                 atomic_inc(&new->mm_users);
 297                 child->mm = new;
 298                 child->active_mm = new;
 299                 mmput(old);
 300                 ret = 0;
 301                 break;
 302         }
 303 #endif
 304         default:
 305                 ret = ptrace_request(child, request, addr, data);
 306                 break;
 307         }
 308  out_tsk:
 309         put_task_struct(child);
 310  out:
 311         unlock_kernel();
 312         return ret;
 313 }
 314
 315 void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
 316                   int error_code)
 317 {
 318         struct siginfo info;
 319
 320         memset(&info, 0, sizeof(info));
 321         info.si_signo = SIGTRAP;
 322         info.si_code = TRAP_BRKPT;
 323
 324         /* User-mode eip? */
 325         info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
 326
 327         /* Send us the fakey SIGTRAP */
 328         force_sig_info(SIGTRAP, &info, tsk);
 329 }
 330
 331 /* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
 332  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
 333  */
 334 void syscall_trace(union uml_pt_regs *regs, int entryexit)
 335 {
 336         int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
 337         int tracesysgood;
 338
 339         if (unlikely(current->audit_context)) {
 340                 if (!entryexit)
 341                         audit_syscall_entry(current, regs->orig_eax,
 342                                             regs->ebx, regs->ecx,
 343                                             regs->edx, regs->esi);
 344                 else
 345                         audit_syscall_exit(current, regs->eax);
 346         }
 347
 348         /* Fake a debug trap */
 349         if (is_singlestep)
 350                 send_sigtrap(current, regs, 0);
 351
 352         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 353                 return;
 354
 355         if (!(current->ptrace & PT_PTRACED))
 356                 return;
 357
 358         /* the 0x80 provides a way for the tracing parent to distinguish
 359            between a syscall stop and SIGTRAP delivery */
 360         tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
 361         ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
 362
 363         if (entryexit) /* force do_signal() --> is_syscall() */
 364                 set_thread_flag(TIF_SIGPENDING);
 365
 366         /* this isn't the same as continuing with a signal, but it will do
 367          * for normal use.  strace only continues with a signal if the
 368          * stopping signal is not SIGTRAP.  -brl
 369          */
 370         if (current->exit_code) {
 371                 send_sig(current->exit_code, current, 1);
 372                 current->exit_code = 0;
 373         }
 374 }
 375
 376 /*
 377  * Overrides for Emacs so that we follow Linus's tabbing style.
 378  * Emacs will notice this stuff at the end of the file and automatically
 379  * adjust the settings for this buffer only.  This must remain at the end
 380  * of the file.
 381  * ---------------------------------------------------------------------------
 382  * Local variables:
 383  * c-file-style: "linux"
 384  * End:
 385  */