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