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