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 static inline void set_singlestepping(struct task_struct *child, int on)
  23 {
  24         if (on)
  25                 child->ptrace |= PT_DTRACE;
  26         else
  27                 child->ptrace &= ~PT_DTRACE;
  28         child->thread.singlestep_syscall = 0;
  29
  30 #ifdef SUBARCH_SET_SINGLESTEPPING
  31         SUBARCH_SET_SINGLESTEPPING(child, on);
  32 #endif
  33 }
  34
  35 /*
  36  * Called by kernel/ptrace.c when detaching..
  37  */
  38 void ptrace_disable(struct task_struct *child)
  39 {
  40         set_singlestepping(child,0);
  41 }
  42
  43 extern int peek_user(struct task_struct * child, long addr, long data);
  44 extern int poke_user(struct task_struct * child, long addr, long data);
  45
  46 long sys_ptrace(long request, long pid, long addr, long data)
  47 {
  48         struct task_struct *child;
  49         int i, ret;
  50
  51         lock_kernel();
  52         ret = -EPERM;
  53         if (request == PTRACE_TRACEME) {
  54                 /* are we already being traced? */
  55                 if (current->ptrace & PT_PTRACED)
  56                         goto out;
  57
  58                 ret = security_ptrace(current->parent, current);
  59                 if (ret)
  60                         goto out;
  61
  62                 /* set the ptrace bit in the process flags. */
  63                 current->ptrace |= PT_PTRACED;
  64                 ret = 0;
  65                 goto out;
  66         }
  67         ret = -ESRCH;
  68         read_lock(&tasklist_lock);
  69         child = find_task_by_pid(pid);
  70         if (child)
  71                 get_task_struct(child);
  72         read_unlock(&tasklist_lock);
  73         if (!child)
  74                 goto out;
  75
  76         ret = -EPERM;
  77         if (pid == 1)           /* you may not mess with init */
  78                 goto out_tsk;
  79
  80         if (request == PTRACE_ATTACH) {
  81                 ret = ptrace_attach(child);
  82                 goto out_tsk;
  83         }
  84
  85 #ifdef SUBACH_PTRACE_SPECIAL
  86         SUBARCH_PTRACE_SPECIAL(child,request,addr,data);
  87 #endif
  88
  89         ret = ptrace_check_attach(child, request == PTRACE_KILL);
  90         if (ret < 0)
  91                 goto out_tsk;
  92
  93         switch (request) {
  94                 /* when I and D space are separate, these will need to be fixed. */
  95         case PTRACE_PEEKTEXT: /* read word at location addr. */
  96         case PTRACE_PEEKDATA: {
  97                 unsigned long tmp;
  98                 int copied;
  99
 100                 ret = -EIO;
 101                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 102                 if (copied != sizeof(tmp))
 103                         break;
 104                 ret = put_user(tmp, (unsigned long __user *) data);
 105                 break;
 106         }
 107
 108         /* read the word at location addr in the USER area. */
 109         case PTRACE_PEEKUSR:
 110                 ret = peek_user(child, addr, data);
 111                 break;
 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 = poke_user(child, addr, data);
 125                 break;
 126
 127         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 128         case PTRACE_CONT: { /* restart after signal. */
 129                 ret = -EIO;
 130                 if (!valid_signal(data))
 131                         break;
 132
 133                 set_singlestepping(child, 0);
 134                 if (request == PTRACE_SYSCALL) {
 135                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 136                 }
 137                 else {
 138                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 139                 }
 140                 child->exit_code = data;
 141                 wake_up_process(child);
 142                 ret = 0;
 143                 break;
 144         }
 145
 146 /*
 147  * make the child exit.  Best I can do is send it a sigkill.
 148  * perhaps it should be put in the status that it wants to
 149  * exit.
 150  */
 151         case PTRACE_KILL: {
 152                 ret = 0;
 153                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 154                         break;
 155
 156                 set_singlestepping(child, 0);
 157                 child->exit_code = SIGKILL;
 158                 wake_up_process(child);
 159                 break;
 160         }
 161
 162         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 163                 ret = -EIO;
 164                 if (!valid_signal(data))
 165                         break;
 166                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 167                 set_singlestepping(child, 1);
 168                 child->exit_code = data;
 169                 /* give it a chance to run. */
 170                 wake_up_process(child);
 171                 ret = 0;
 172                 break;
 173         }
 174
 175         case PTRACE_DETACH:
 176                 /* detach a process that was attached. */
 177                 ret = ptrace_detach(child, data);
 178                 break;
 179
 180 #ifdef PTRACE_GETREGS
 181         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 182                 if (!access_ok(VERIFY_WRITE, (unsigned long *)data,
 183                                MAX_REG_OFFSET)) {
 184                         ret = -EIO;
 185                         break;
 186                 }
 187                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 188                         __put_user(getreg(child, i),
 189                                    (unsigned long __user *) data);
 190                         data += sizeof(long);
 191                 }
 192                 ret = 0;
 193                 break;
 194         }
 195 #endif
 196 #ifdef PTRACE_SETREGS
 197         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 198                 unsigned long tmp = 0;
 199                 if (!access_ok(VERIFY_READ, (unsigned *)data,
 200                                MAX_REG_OFFSET)) {
 201                         ret = -EIO;
 202                         break;
 203                 }
 204                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 205                         __get_user(tmp, (unsigned long __user *) data);
 206                         putreg(child, i, tmp);
 207                         data += sizeof(long);
 208                 }
 209                 ret = 0;
 210                 break;
 211         }
 212 #endif
 213 #ifdef PTRACE_GETFPREGS
 214         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 215                 ret = get_fpregs(data, child);
 216                 break;
 217 #endif
 218 #ifdef PTRACE_SETFPREGS
 219         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 220                 ret = set_fpregs(data, child);
 221                 break;
 222 #endif
 223 #ifdef PTRACE_GETFPXREGS
 224         case PTRACE_GETFPXREGS: /* Get the child FPU state. */
 225                 ret = get_fpxregs(data, child);
 226                 break;
 227 #endif
 228 #ifdef PTRACE_SETFPXREGS
 229         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 230                 ret = set_fpxregs(data, child);
 231                 break;
 232 #endif
 233         case PTRACE_FAULTINFO: {
 234                 /* Take the info from thread->arch->faultinfo,
 235                  * but transfer max. sizeof(struct ptrace_faultinfo).
 236                  * On i386, ptrace_faultinfo is smaller!
 237                  */
 238                 ret = copy_to_user((unsigned long __user *) data,
 239                                    &child->thread.arch.faultinfo,
 240                                    sizeof(struct ptrace_faultinfo));
 241                 if(ret)
 242                         break;
 243                 break;
 244         }
 245
 246 #ifdef PTRACE_LDT
 247         case PTRACE_LDT: {
 248                 struct ptrace_ldt ldt;
 249
 250                 if(copy_from_user(&ldt, (unsigned long __user *) data,
 251                                   sizeof(ldt))){
 252                         ret = -EIO;
 253                         break;
 254                 }
 255
 256                 /* This one is confusing, so just punt and return -EIO for
 257                  * now
 258                  */
 259                 ret = -EIO;
 260                 break;
 261         }
 262 #endif
 263 #ifdef CONFIG_PROC_MM
 264         case PTRACE_SWITCH_MM: {
 265                 struct mm_struct *old = child->mm;
 266                 struct mm_struct *new = proc_mm_get_mm(data);
 267
 268                 if(IS_ERR(new)){
 269                         ret = PTR_ERR(new);
 270                         break;
 271                 }
 272
 273                 atomic_inc(&new->mm_users);
 274                 child->mm = new;
 275                 child->active_mm = new;
 276                 mmput(old);
 277                 ret = 0;
 278                 break;
 279         }
 280 #endif
 281         default:
 282                 ret = ptrace_request(child, request, addr, data);
 283                 break;
 284         }
 285  out_tsk:
 286         put_task_struct(child);
 287  out:
 288         unlock_kernel();
 289         return ret;
 290 }
 291
 292 void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
 293                   int error_code)
 294 {
 295         struct siginfo info;
 296
 297         memset(&info, 0, sizeof(info));
 298         info.si_signo = SIGTRAP;
 299         info.si_code = TRAP_BRKPT;
 300
 301         /* User-mode eip? */
 302         info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
 303
 304         /* Send us the fakey SIGTRAP */
 305         force_sig_info(SIGTRAP, &info, tsk);
 306 }
 307
 308 /* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
 309  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
 310  */
 311 void syscall_trace(union uml_pt_regs *regs, int entryexit)
 312 {
 313         int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
 314         int tracesysgood;
 315
 316         if (unlikely(current->audit_context)) {
 317                 if (!entryexit)
 318                         audit_syscall_entry(current,
 319                                             HOST_AUDIT_ARCH,
 320                                             UPT_SYSCALL_NR(regs),
 321                                             UPT_SYSCALL_ARG1(regs),
 322                                             UPT_SYSCALL_ARG2(regs),
 323                                             UPT_SYSCALL_ARG3(regs),
 324                                             UPT_SYSCALL_ARG4(regs));
 325                 else audit_syscall_exit(current,
 326                                         AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
 327                                         UPT_SYSCALL_RET(regs));
 328         }
 329
 330         /* Fake a debug trap */
 331         if (is_singlestep)
 332                 send_sigtrap(current, regs, 0);
 333
 334         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 335                 return;
 336
 337         if (!(current->ptrace & PT_PTRACED))
 338                 return;
 339
 340         /* the 0x80 provides a way for the tracing parent to distinguish
 341            between a syscall stop and SIGTRAP delivery */
 342         tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
 343         ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
 344
 345         if (entryexit) /* force do_signal() --> is_syscall() */
 346                 set_thread_flag(TIF_SIGPENDING);
 347
 348         /* this isn't the same as continuing with a signal, but it will do
 349          * for normal use.  strace only continues with a signal if the
 350          * stopping signal is not SIGTRAP.  -brl
 351          */
 352         if (current->exit_code) {
 353                 send_sig(current->exit_code, current, 1);
 354                 current->exit_code = 0;
 355         }
 356 }