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         void __user *vp = p;
  51
  52         switch (request) {
  53         /* read the word at location addr in the USER area. */
  54         case PTRACE_PEEKUSR:
  55                 ret = peek_user(child, addr, data);
  56                 break;
  57
  58         /* write the word at location addr in the USER area */
  59         case PTRACE_POKEUSR:
  60                 ret = poke_user(child, addr, data);
  61                 break;
  62
  63         case PTRACE_SYSEMU:
  64         case PTRACE_SYSEMU_SINGLESTEP:
  65                 ret = -EIO;
  66                 break;
  67
  68 #ifdef PTRACE_GETREGS
  69         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
  70                 if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
  71                         ret = -EIO;
  72                         break;
  73                 }
  74                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
  75                         __put_user(getreg(child, i), p);
  76                         p++;
  77                 }
  78                 ret = 0;
  79                 break;
  80         }
  81 #endif
  82 #ifdef PTRACE_SETREGS
  83         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
  84                 unsigned long tmp = 0;
  85                 if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
  86                         ret = -EIO;
  87                         break;
  88                 }
  89                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
  90                         __get_user(tmp, p);
  91                         putreg(child, i, tmp);
  92                         p++;
  93                 }
  94                 ret = 0;
  95                 break;
  96         }
  97 #endif
  98         case PTRACE_GET_THREAD_AREA:
  99                 ret = ptrace_get_thread_area(child, addr, vp);
 100                 break;
 101
 102         case PTRACE_SET_THREAD_AREA:
 103                 ret = ptrace_set_thread_area(child, addr, vp);
 104                 break;
 105
 106         case PTRACE_FAULTINFO: {
 107                 /*
 108                  * Take the info from thread->arch->faultinfo,
 109                  * but transfer max. sizeof(struct ptrace_faultinfo).
 110                  * On i386, ptrace_faultinfo is smaller!
 111                  */
 112                 ret = copy_to_user(p, &child->thread.arch.faultinfo,
 113                                    sizeof(struct ptrace_faultinfo)) ?
 114                         -EIO : 0;
 115                 break;
 116         }
 117
 118 #ifdef PTRACE_LDT
 119         case PTRACE_LDT: {
 120                 struct ptrace_ldt ldt;
 121
 122                 if (copy_from_user(&ldt, p, sizeof(ldt))) {
 123                         ret = -EIO;
 124                         break;
 125                 }
 126
 127                 /*
 128                  * This one is confusing, so just punt and return -EIO for
 129                  * now
 130                  */
 131                 ret = -EIO;
 132                 break;
 133         }
 134 #endif
 135         default:
 136                 ret = ptrace_request(child, request, addr, data);
 137                 if (ret == -EIO)
 138                         ret = subarch_ptrace(child, request, addr, data);
 139                 break;
 140         }
 141
 142         return ret;
 143 }
 144
 145 static void send_sigtrap(struct task_struct *tsk, struct uml_pt_regs *regs,
 146                   int error_code)
 147 {
 148         struct siginfo info;
 149
 150         memset(&info, 0, sizeof(info));
 151         info.si_signo = SIGTRAP;
 152         info.si_code = TRAP_BRKPT;
 153
 154         /* User-mode eip? */
 155         info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
 156
 157         /* Send us the fake SIGTRAP */
 158         force_sig_info(SIGTRAP, &info, tsk);
 159 }
 160
 161 /*
 162  * XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
 163  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
 164  */
 165 void syscall_trace(struct uml_pt_regs *regs, int entryexit)
 166 {
 167         int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
 168         int tracesysgood;
 169
 170         if (unlikely(current->audit_context)) {
 171                 if (!entryexit)
 172                         audit_syscall_entry(HOST_AUDIT_ARCH,
 173                                             UPT_SYSCALL_NR(regs),
 174                                             UPT_SYSCALL_ARG1(regs),
 175                                             UPT_SYSCALL_ARG2(regs),
 176                                             UPT_SYSCALL_ARG3(regs),
 177                                             UPT_SYSCALL_ARG4(regs));
 178                 else
 179                         audit_syscall_exit(regs);
 180         }
 181
 182         /* Fake a debug trap */
 183         if (is_singlestep)
 184                 send_sigtrap(current, regs, 0);
 185
 186         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 187                 return;
 188
 189         if (!(current->ptrace & PT_PTRACED))
 190                 return;
 191
 192         /*
 193          * the 0x80 provides a way for the tracing parent to distinguish
 194          * between a syscall stop and SIGTRAP delivery
 195          */
 196         tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
 197         ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
 198
 199         if (entryexit) /* force do_signal() --> is_syscall() */
 200                 set_thread_flag(TIF_SIGPENDING);
 201
 202         /*
 203          * this isn't the same as continuing with a signal, but it will do
 204          * for normal use.  strace only continues with a signal if the
 205          * stopping signal is not SIGTRAP.  -brl
 206          */
 207         if (current->exit_code) {
 208                 send_sig(current->exit_code, current, 1);
 209                 current->exit_code = 0;
 210         }
 211 }