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