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 #include "skas_ptrace.h"
  11
  12
  13
  14 void user_enable_single_step(struct task_struct *child)
  15 {
  16         child->ptrace |= PT_DTRACE;
  17         child->thread.singlestep_syscall = 0;
  18
  19 #ifdef SUBARCH_SET_SINGLESTEPPING
  20         SUBARCH_SET_SINGLESTEPPING(child, 1);
  21 #endif
  22 }
  23
  24 void user_disable_single_step(struct task_struct *child)
  25 {
  26         child->ptrace &= ~PT_DTRACE;
  27         child->thread.singlestep_syscall = 0;
  28
  29 #ifdef SUBARCH_SET_SINGLESTEPPING
  30         SUBARCH_SET_SINGLESTEPPING(child, 0);
  31 #endif
  32 }
  33
  34 /*
  35  * Called by kernel/ptrace.c when detaching..
  36  */
  37 void ptrace_disable(struct task_struct *child)
  38 {
  39         user_disable_single_step(child);
  40 }
  41
  42 extern int peek_user(struct task_struct * child, long addr, long data);
  43 extern int poke_user(struct task_struct * child, long addr, long data);
  44
  45 long arch_ptrace(struct task_struct *child, long request,
  46                  unsigned long addr, unsigned long data)
  47 {
  48         int i, ret;
  49         unsigned long __user *p = (void __user *)data;
  50
  51         switch (request) {
  52         /* read word at location addr. */
  53         case PTRACE_PEEKTEXT:
  54         case PTRACE_PEEKDATA:
  55                 ret = generic_ptrace_peekdata(child, addr, data);
  56                 break;
  57
  58         /* read the word at location addr in the USER area. */
  59         case PTRACE_PEEKUSR:
  60                 ret = peek_user(child, addr, data);
  61                 break;
  62
  63         /* write the word at location addr. */
  64         case PTRACE_POKETEXT:
  65         case PTRACE_POKEDATA:
  66                 ret = generic_ptrace_pokedata(child, addr, data);
  67                 break;
  68
  69         /* write the word at location addr in the USER area */
  70         case PTRACE_POKEUSR:
  71                 ret = poke_user(child, addr, data);
  72                 break;
  73
  74         case PTRACE_SYSEMU:
  75         case PTRACE_SYSEMU_SINGLESTEP:
  76                 ret = -EIO;
  77                 break;
  78
  79 #ifdef PTRACE_GETREGS
  80         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
  81                 if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
  82                         ret = -EIO;
  83                         break;
  84                 }
  85                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
  86                         __put_user(getreg(child, i), p);
  87                         p++;
  88                 }
  89                 ret = 0;
  90                 break;
  91         }
  92 #endif
  93 #ifdef PTRACE_SETREGS
  94         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
  95                 unsigned long tmp = 0;
  96                 if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
  97                         ret = -EIO;
  98                         break;
  99                 }
 100                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 101                         __get_user(tmp, p);
 102                         putreg(child, i, tmp);
 103                         p++;
 104                 }
 105                 ret = 0;
 106                 break;
 107         }
 108 #endif
 109 #ifdef PTRACE_GETFPREGS
 110         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 111                 ret = get_fpregs((struct user_i387_struct __user *) data,
 112                                  child);
 113                 break;
 114 #endif
 115 #ifdef PTRACE_SETFPREGS
 116         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 117                 ret = set_fpregs((struct user_i387_struct __user *) data,
 118                                  child);
 119                 break;
 120 #endif
 121         case PTRACE_GET_THREAD_AREA:
 122                 ret = ptrace_get_thread_area(child, addr,
 123                                              (struct user_desc __user *) data);
 124                 break;
 125
 126         case PTRACE_SET_THREAD_AREA:
 127                 ret = ptrace_set_thread_area(child, addr,
 128                                              (struct user_desc __user *) data);
 129                 break;
 130
 131         case PTRACE_FAULTINFO: {
 132                 /*
 133                  * Take the info from thread->arch->faultinfo,
 134                  * but transfer max. sizeof(struct ptrace_faultinfo).
 135                  * On i386, ptrace_faultinfo is smaller!
 136                  */
 137                 ret = copy_to_user(p, &child->thread.arch.faultinfo,
 138                                    sizeof(struct ptrace_faultinfo));
 139                 break;
 140         }
 141
 142 #ifdef PTRACE_LDT
 143         case PTRACE_LDT: {
 144                 struct ptrace_ldt ldt;
 145
 146                 if (copy_from_user(&ldt, p, sizeof(ldt))) {
 147                         ret = -EIO;
 148                         break;
 149                 }
 150
 151                 /*
 152                  * This one is confusing, so just punt and return -EIO for
 153                  * now
 154                  */
 155                 ret = -EIO;
 156                 break;
 157         }
 158 #endif
 159 #ifdef PTRACE_ARCH_PRCTL
 160         case PTRACE_ARCH_PRCTL:
 161                 /* XXX Calls ptrace on the host - needs some SMP thinking */
 162                 ret = arch_prctl(child, data, (void *) addr);
 163                 break;
 164 #endif
 165         default:
 166                 ret = ptrace_request(child, request, addr, data);
 167                 if (ret == -EIO)
 168                         ret = subarch_ptrace(child, request, addr, data);
 169                 break;
 170         }
 171
 172         return ret;
 173 }
 174
 175 static void send_sigtrap(struct task_struct *tsk, struct uml_pt_regs *regs,
 176                   int error_code)
 177 {
 178         struct siginfo info;
 179
 180         memset(&info, 0, sizeof(info));
 181         info.si_signo = SIGTRAP;
 182         info.si_code = TRAP_BRKPT;
 183
 184         /* User-mode eip? */
 185         info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
 186
 187         /* Send us the fake SIGTRAP */
 188         force_sig_info(SIGTRAP, &info, tsk);
 189 }
 190
 191 /*
 192  * XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
 193  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
 194  */
 195 void syscall_trace(struct uml_pt_regs *regs, int entryexit)
 196 {
 197         int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
 198         int tracesysgood;
 199
 200         if (unlikely(current->audit_context)) {
 201                 if (!entryexit)
 202                         audit_syscall_entry(HOST_AUDIT_ARCH,
 203                                             UPT_SYSCALL_NR(regs),
 204                                             UPT_SYSCALL_ARG1(regs),
 205                                             UPT_SYSCALL_ARG2(regs),
 206                                             UPT_SYSCALL_ARG3(regs),
 207                                             UPT_SYSCALL_ARG4(regs));
 208                 else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
 209                                         UPT_SYSCALL_RET(regs));
 210         }
 211
 212         /* Fake a debug trap */
 213         if (is_singlestep)
 214                 send_sigtrap(current, regs, 0);
 215
 216         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 217                 return;
 218
 219         if (!(current->ptrace & PT_PTRACED))
 220                 return;
 221
 222         /*
 223          * the 0x80 provides a way for the tracing parent to distinguish
 224          * between a syscall stop and SIGTRAP delivery
 225          */
 226         tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
 227         ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
 228
 229         if (entryexit) /* force do_signal() --> is_syscall() */
 230                 set_thread_flag(TIF_SIGPENDING);
 231
 232         /*
 233          * this isn't the same as continuing with a signal, but it will do
 234          * for normal use.  strace only continues with a signal if the
 235          * stopping signal is not SIGTRAP.  -brl
 236          */
 237         if (current->exit_code) {
 238                 send_sig(current->exit_code, current, 1);
 239                 current->exit_code = 0;
 240         }
 241 }