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