arch/um/kernel/ptrace.c

   1 /*
   2  * Copyright (C) 2000 - 2007 Jeff Dike (jdike@{addtoit,linux.intel}.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/audit.h"
   7 #include "linux/ptrace.h"
   8 #include "linux/sched.h"
   9 #include "asm/uaccess.h"
  10 #ifdef CONFIG_PROC_MM
  11 #include "proc_mm.h"
  12 #endif
  13 #include "skas_ptrace.h"
  14
  15 static inline void set_singlestepping(struct task_struct *child, int on)
  16 {
  17         if (on)
  18                 child->ptrace |= PT_DTRACE;
  19         else
  20                 child->ptrace &= ~PT_DTRACE;
  21         child->thread.singlestep_syscall = 0;
  22
  23 #ifdef SUBARCH_SET_SINGLESTEPPING
  24         SUBARCH_SET_SINGLESTEPPING(child, on);
  25 #endif
  26 }
  27
  28 /*
  29  * Called by kernel/ptrace.c when detaching..
  30  */
  31 void ptrace_disable(struct task_struct *child)
  32 {
  33         set_singlestepping(child,0);
  34 }
  35
  36 extern int peek_user(struct task_struct * child, long addr, long data);
  37 extern int poke_user(struct task_struct * child, long addr, long data);
  38
  39 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
  40 {
  41         int i, ret;
  42         unsigned long __user *p = (void __user *)(unsigned long)data;
  43
  44         switch (request) {
  45         /* read word at location addr. */
  46         case PTRACE_PEEKTEXT:
  47         case PTRACE_PEEKDATA:
  48                 ret = generic_ptrace_peekdata(child, addr, data);
  49                 break;
  50
  51         /* read the word at location addr in the USER area. */
  52         case PTRACE_PEEKUSR:
  53                 ret = peek_user(child, addr, data);
  54                 break;
  55
  56         /* write the word at location addr. */
  57         case PTRACE_POKETEXT:
  58         case PTRACE_POKEDATA:
  59                 ret = generic_ptrace_pokedata(child, addr, data);
  60                 break;
  61
  62         /* write the word at location addr in the USER area */
  63         case PTRACE_POKEUSR:
  64                 ret = poke_user(child, addr, data);
  65                 break;
  66
  67         /* continue and stop at next (return from) syscall */
  68         case PTRACE_SYSCALL:
  69         /* restart after signal. */
  70         case PTRACE_CONT: {
  71                 ret = -EIO;
  72                 if (!valid_signal(data))
  73                         break;
  74
  75                 set_singlestepping(child, 0);
  76                 if (request == PTRACE_SYSCALL)
  77                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
  78                 else clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
  79                 child->exit_code = data;
  80                 wake_up_process(child);
  81                 ret = 0;
  82                 break;
  83         }
  84
  85 /*
  86  * make the child exit.  Best I can do is send it a sigkill.
  87  * perhaps it should be put in the status that it wants to
  88  * exit.
  89  */
  90         case PTRACE_KILL: {
  91                 ret = 0;
  92                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
  93                         break;
  94
  95                 set_singlestepping(child, 0);
  96                 child->exit_code = SIGKILL;
  97                 wake_up_process(child);
  98                 break;
  99         }
 100
 101         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 102                 ret = -EIO;
 103                 if (!valid_signal(data))
 104                         break;
 105                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 106                 set_singlestepping(child, 1);
 107                 child->exit_code = data;
 108                 /* give it a chance to run. */
 109                 wake_up_process(child);
 110                 ret = 0;
 111                 break;
 112         }
 113
 114 #ifdef PTRACE_GETREGS
 115         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 116                 if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
 117                         ret = -EIO;
 118                         break;
 119                 }
 120                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 121                         __put_user(getreg(child, i), p);
 122                         p++;
 123                 }
 124                 ret = 0;
 125                 break;
 126         }
 127 #endif
 128 #ifdef PTRACE_SETREGS
 129         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 130                 unsigned long tmp = 0;
 131                 if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
 132                         ret = -EIO;
 133                         break;
 134                 }
 135                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 136                         __get_user(tmp, p);
 137                         putreg(child, i, tmp);
 138                         p++;
 139                 }
 140                 ret = 0;
 141                 break;
 142         }
 143 #endif
 144 #ifdef PTRACE_GETFPREGS
 145         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 146                 ret = get_fpregs((struct user_i387_struct __user *) data,
 147                                  child);
 148                 break;
 149 #endif
 150 #ifdef PTRACE_SETFPREGS
 151         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 152                 ret = set_fpregs((struct user_i387_struct __user *) data,
 153                                  child);
 154                 break;
 155 #endif
 156         case PTRACE_GET_THREAD_AREA:
 157                 ret = ptrace_get_thread_area(child, addr,
 158                                              (struct user_desc __user *) data);
 159                 break;
 160
 161         case PTRACE_SET_THREAD_AREA:
 162                 ret = ptrace_set_thread_area(child, addr,
 163                                              (struct user_desc __user *) data);
 164                 break;
 165
 166         case PTRACE_FAULTINFO: {
 167                 /*
 168                  * Take the info from thread->arch->faultinfo,
 169                  * but transfer max. sizeof(struct ptrace_faultinfo).
 170                  * On i386, ptrace_faultinfo is smaller!
 171                  */
 172                 ret = copy_to_user(p, &child->thread.arch.faultinfo,
 173                                    sizeof(struct ptrace_faultinfo));
 174                 if (ret)
 175                         break;
 176                 break;
 177         }
 178
 179 #ifdef PTRACE_LDT
 180         case PTRACE_LDT: {
 181                 struct ptrace_ldt ldt;
 182
 183                 if (copy_from_user(&ldt, p, sizeof(ldt))) {
 184                         ret = -EIO;
 185                         break;
 186                 }
 187
 188                 /*
 189                  * This one is confusing, so just punt and return -EIO for
 190                  * now
 191                  */
 192                 ret = -EIO;
 193                 break;
 194         }
 195 #endif
 196 #ifdef CONFIG_PROC_MM
 197         case PTRACE_SWITCH_MM: {
 198                 struct mm_struct *old = child->mm;
 199                 struct mm_struct *new = proc_mm_get_mm(data);
 200
 201                 if (IS_ERR(new)) {
 202                         ret = PTR_ERR(new);
 203                         break;
 204                 }
 205
 206                 atomic_inc(&new->mm_users);
 207                 child->mm = new;
 208                 child->active_mm = new;
 209                 mmput(old);
 210                 ret = 0;
 211                 break;
 212         }
 213 #endif
 214 #ifdef PTRACE_ARCH_PRCTL
 215         case PTRACE_ARCH_PRCTL:
 216                 /* XXX Calls ptrace on the host - needs some SMP thinking */
 217                 ret = arch_prctl(child, data, (void *) addr);
 218                 break;
 219 #endif
 220         default:
 221                 ret = ptrace_request(child, request, addr, data);
 222                 if (ret == -EIO)
 223                         ret = subarch_ptrace(child, request, addr, data);
 224                 break;
 225         }
 226
 227         return ret;
 228 }
 229
 230 void send_sigtrap(struct task_struct *tsk, struct uml_pt_regs *regs,
 231                   int error_code)
 232 {
 233         struct siginfo info;
 234
 235         memset(&info, 0, sizeof(info));
 236         info.si_signo = SIGTRAP;
 237         info.si_code = TRAP_BRKPT;
 238
 239         /* User-mode eip? */
 240         info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
 241
 242         /* Send us the fakey SIGTRAP */
 243         force_sig_info(SIGTRAP, &info, tsk);
 244 }
 245
 246 /*
 247  * XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
 248  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
 249  */
 250 void syscall_trace(struct uml_pt_regs *regs, int entryexit)
 251 {
 252         int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
 253         int tracesysgood;
 254
 255         if (unlikely(current->audit_context)) {
 256                 if (!entryexit)
 257                         audit_syscall_entry(HOST_AUDIT_ARCH,
 258                                             UPT_SYSCALL_NR(regs),
 259                                             UPT_SYSCALL_ARG1(regs),
 260                                             UPT_SYSCALL_ARG2(regs),
 261                                             UPT_SYSCALL_ARG3(regs),
 262                                             UPT_SYSCALL_ARG4(regs));
 263                 else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
 264                                         UPT_SYSCALL_RET(regs));
 265         }
 266
 267         /* Fake a debug trap */
 268         if (is_singlestep)
 269                 send_sigtrap(current, regs, 0);
 270
 271         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 272                 return;
 273
 274         if (!(current->ptrace & PT_PTRACED))
 275                 return;
 276
 277         /*
 278          * the 0x80 provides a way for the tracing parent to distinguish
 279          * between a syscall stop and SIGTRAP delivery
 280          */
 281         tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
 282         ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
 283
 284         if (entryexit) /* force do_signal() --> is_syscall() */
 285                 set_thread_flag(TIF_SIGPENDING);
 286
 287         /*
 288          * this isn't the same as continuing with a signal, but it will do
 289          * for normal use.  strace only continues with a signal if the
 290          * stopping signal is not SIGTRAP.  -brl
 291          */
 292         if (current->exit_code) {
 293                 send_sig(current->exit_code, current, 1);
 294                 current->exit_code = 0;
 295         }
 296 }