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 #include "os.h"
  22
  23 static inline void set_singlestepping(struct task_struct *child, int on)
  24 {
  25         if (on)
  26                 child->ptrace |= PT_DTRACE;
  27         else
  28                 child->ptrace &= ~PT_DTRACE;
  29         child->thread.singlestep_syscall = 0;
  30
  31 #ifdef SUBARCH_SET_SINGLESTEPPING
  32         SUBARCH_SET_SINGLESTEPPING(child, on);
  33 #endif
  34 }
  35
  36 /*
  37  * Called by kernel/ptrace.c when detaching..
  38  */
  39 void ptrace_disable(struct task_struct *child)
  40 {
  41         set_singlestepping(child,0);
  42 }
  43
  44 extern int peek_user(struct task_struct * child, long addr, long data);
  45 extern int poke_user(struct task_struct * child, long addr, long data);
  46
  47 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
  48 {
  49         int i, ret;
  50         unsigned long __user *p = (void __user *)(unsigned long)data;
  51
  52         switch (request) {
  53                 /* when I and D space are separate, these will need to be fixed. */
  54         case PTRACE_PEEKTEXT: /* read word at location addr. */
  55         case PTRACE_PEEKDATA:
  56                 ret = generic_ptrace_peekdata(child, addr, data);
  57                 break;
  58
  59         /* read the word at location addr in the USER area. */
  60         case PTRACE_PEEKUSR:
  61                 ret = peek_user(child, addr, data);
  62                 break;
  63
  64         /* when I and D space are separate, this will have to be fixed. */
  65         case PTRACE_POKETEXT: /* write the word at location addr. */
  66         case PTRACE_POKEDATA:
  67                 ret = -EIO;
  68                 if (access_process_vm(child, addr, &data, sizeof(data),
  69                                       1) != sizeof(data))
  70                         break;
  71                 ret = 0;
  72                 break;
  73
  74         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
  75                 ret = poke_user(child, addr, data);
  76                 break;
  77
  78         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
  79         case PTRACE_CONT: { /* restart after signal. */
  80                 ret = -EIO;
  81                 if (!valid_signal(data))
  82                         break;
  83
  84                 set_singlestepping(child, 0);
  85                 if (request == PTRACE_SYSCALL) {
  86                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
  87                 }
  88                 else {
  89                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
  90                 }
  91                 child->exit_code = data;
  92                 wake_up_process(child);
  93                 ret = 0;
  94                 break;
  95         }
  96
  97 /*
  98  * make the child exit.  Best I can do is send it a sigkill.
  99  * perhaps it should be put in the status that it wants to
 100  * exit.
 101  */
 102         case PTRACE_KILL: {
 103                 ret = 0;
 104                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 105                         break;
 106
 107                 set_singlestepping(child, 0);
 108                 child->exit_code = SIGKILL;
 109                 wake_up_process(child);
 110                 break;
 111         }
 112
 113         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 114                 ret = -EIO;
 115                 if (!valid_signal(data))
 116                         break;
 117                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 118                 set_singlestepping(child, 1);
 119                 child->exit_code = data;
 120                 /* give it a chance to run. */
 121                 wake_up_process(child);
 122                 ret = 0;
 123                 break;
 124         }
 125
 126         case PTRACE_DETACH:
 127                 /* detach a process that was attached. */
 128                 ret = ptrace_detach(child, data);
 129                 break;
 130
 131 #ifdef PTRACE_GETREGS
 132         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 133                 if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
 134                         ret = -EIO;
 135                         break;
 136                 }
 137                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 138                         __put_user(getreg(child, i), p);
 139                         p++;
 140                 }
 141                 ret = 0;
 142                 break;
 143         }
 144 #endif
 145 #ifdef PTRACE_SETREGS
 146         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 147                 unsigned long tmp = 0;
 148                 if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
 149                         ret = -EIO;
 150                         break;
 151                 }
 152                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 153                         __get_user(tmp, p);
 154                         putreg(child, i, tmp);
 155                         p++;
 156                 }
 157                 ret = 0;
 158                 break;
 159         }
 160 #endif
 161 #ifdef PTRACE_GETFPREGS
 162         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 163                 ret = get_fpregs(data, child);
 164                 break;
 165 #endif
 166 #ifdef PTRACE_SETFPREGS
 167         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 168                 ret = set_fpregs(data, child);
 169                 break;
 170 #endif
 171 #ifdef PTRACE_GETFPXREGS
 172         case PTRACE_GETFPXREGS: /* Get the child FPU state. */
 173                 ret = get_fpxregs(data, child);
 174                 break;
 175 #endif
 176 #ifdef PTRACE_SETFPXREGS
 177         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 178                 ret = set_fpxregs(data, child);
 179                 break;
 180 #endif
 181         case PTRACE_GET_THREAD_AREA:
 182                 ret = ptrace_get_thread_area(child, addr,
 183                                              (struct user_desc __user *) data);
 184                 break;
 185
 186         case PTRACE_SET_THREAD_AREA:
 187                 ret = ptrace_set_thread_area(child, addr,
 188                                              (struct user_desc __user *) data);
 189                 break;
 190
 191         case PTRACE_FAULTINFO: {
 192                 /* Take the info from thread->arch->faultinfo,
 193                  * but transfer max. sizeof(struct ptrace_faultinfo).
 194                  * On i386, ptrace_faultinfo is smaller!
 195                  */
 196                 ret = copy_to_user(p, &child->thread.arch.faultinfo,
 197                                    sizeof(struct ptrace_faultinfo));
 198                 if(ret)
 199                         break;
 200                 break;
 201         }
 202
 203 #ifdef PTRACE_LDT
 204         case PTRACE_LDT: {
 205                 struct ptrace_ldt ldt;
 206
 207                 if(copy_from_user(&ldt, p, sizeof(ldt))){
 208                         ret = -EIO;
 209                         break;
 210                 }
 211
 212                 /* This one is confusing, so just punt and return -EIO for
 213                  * now
 214                  */
 215                 ret = -EIO;
 216                 break;
 217         }
 218 #endif
 219 #ifdef CONFIG_PROC_MM
 220         case PTRACE_SWITCH_MM: {
 221                 struct mm_struct *old = child->mm;
 222                 struct mm_struct *new = proc_mm_get_mm(data);
 223
 224                 if(IS_ERR(new)){
 225                         ret = PTR_ERR(new);
 226                         break;
 227                 }
 228
 229                 atomic_inc(&new->mm_users);
 230                 child->mm = new;
 231                 child->active_mm = new;
 232                 mmput(old);
 233                 ret = 0;
 234                 break;
 235         }
 236 #endif
 237 #ifdef PTRACE_ARCH_PRCTL
 238         case PTRACE_ARCH_PRCTL:
 239                 /* XXX Calls ptrace on the host - needs some SMP thinking */
 240                 ret = arch_prctl_skas(child, data, (void *) addr);
 241                 break;
 242 #endif
 243         default:
 244                 ret = ptrace_request(child, request, addr, data);
 245                 break;
 246         }
 247
 248         return ret;
 249 }
 250
 251 void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
 252                   int error_code)
 253 {
 254         struct siginfo info;
 255
 256         memset(&info, 0, sizeof(info));
 257         info.si_signo = SIGTRAP;
 258         info.si_code = TRAP_BRKPT;
 259
 260         /* User-mode eip? */
 261         info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
 262
 263         /* Send us the fakey SIGTRAP */
 264         force_sig_info(SIGTRAP, &info, tsk);
 265 }
 266
 267 /* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
 268  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
 269  */
 270 void syscall_trace(union uml_pt_regs *regs, int entryexit)
 271 {
 272         int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
 273         int tracesysgood;
 274
 275         if (unlikely(current->audit_context)) {
 276                 if (!entryexit)
 277                         audit_syscall_entry(HOST_AUDIT_ARCH,
 278                                             UPT_SYSCALL_NR(regs),
 279                                             UPT_SYSCALL_ARG1(regs),
 280                                             UPT_SYSCALL_ARG2(regs),
 281                                             UPT_SYSCALL_ARG3(regs),
 282                                             UPT_SYSCALL_ARG4(regs));
 283                 else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
 284                                         UPT_SYSCALL_RET(regs));
 285         }
 286
 287         /* Fake a debug trap */
 288         if (is_singlestep)
 289                 send_sigtrap(current, regs, 0);
 290
 291         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 292                 return;
 293
 294         if (!(current->ptrace & PT_PTRACED))
 295                 return;
 296
 297         /* the 0x80 provides a way for the tracing parent to distinguish
 298            between a syscall stop and SIGTRAP delivery */
 299         tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
 300         ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
 301
 302         if (entryexit) /* force do_signal() --> is_syscall() */
 303                 set_thread_flag(TIF_SIGPENDING);
 304
 305         /* this isn't the same as continuing with a signal, but it will do
 306          * for normal use.  strace only continues with a signal if the
 307          * stopping signal is not SIGTRAP.  -brl
 308          */
 309         if (current->exit_code) {
 310                 send_sig(current->exit_code, current, 1);
 311                 current->exit_code = 0;
 312         }
 313 }