arch/um/kernel/ptrace.c

   1 /*
   2  * Copyright (C) 2000 Jeff Dike (jdike@karaya.com)
   3  * Licensed under the GPL
   4  */
   5
   6 #include "linux/sched.h"
   7 #include "linux/mm.h"
   8 #include "linux/errno.h"
   9 #include "linux/smp_lock.h"
  10 #include "linux/security.h"
  11 #include "linux/ptrace.h"
  12 #include "linux/audit.h"
  13 #ifdef CONFIG_PROC_MM
  14 #include "linux/proc_mm.h"
  15 #endif
  16 #include "asm/ptrace.h"
  17 #include "asm/uaccess.h"
  18 #include "kern_util.h"
  19 #include "skas_ptrace.h"
  20 #include "sysdep/ptrace.h"
  21 #include "os.h"
  22
  23 static inline void set_singlestepping(struct task_struct *child, int on)
  24 {
  25         if (on)
  26                 child->ptrace |= PT_DTRACE;
  27         else
  28                 child->ptrace &= ~PT_DTRACE;
  29         child->thread.singlestep_syscall = 0;
  30
  31 #ifdef SUBARCH_SET_SINGLESTEPPING
  32         SUBARCH_SET_SINGLESTEPPING(child, on);
  33 #endif
  34 }
  35
  36 /*
  37  * Called by kernel/ptrace.c when detaching..
  38  */
  39 void ptrace_disable(struct task_struct *child)
  40 {
  41         set_singlestepping(child,0);
  42 }
  43
  44 extern int peek_user(struct task_struct * child, long addr, long data);
  45 extern int poke_user(struct task_struct * child, long addr, long data);
  46
  47 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
  48 {
  49         int i, ret;
  50         unsigned long __user *p = (void __user *)(unsigned long)data;
  51
  52         switch (request) {
  53                 /* when I and D space are separate, these will need to be fixed. */
  54         case PTRACE_PEEKTEXT: /* read word at location addr. */
  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         /* when I and D space are separate, this will have to be fixed. */
  65         case PTRACE_POKETEXT: /* write the word at location addr. */
  66         case PTRACE_POKEDATA:
  67                 ret = generic_ptrace_pokedata(child, addr, data);
  68                 break;
  69
  70         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
  71                 ret = poke_user(child, addr, data);
  72                 break;
  73
  74         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
  75         case PTRACE_CONT: { /* restart after signal. */
  76                 ret = -EIO;
  77                 if (!valid_signal(data))
  78                         break;
  79
  80                 set_singlestepping(child, 0);
  81                 if (request == PTRACE_SYSCALL) {
  82                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
  83                 }
  84                 else {
  85                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
  86                 }
  87                 child->exit_code = data;
  88                 wake_up_process(child);
  89                 ret = 0;
  90                 break;
  91         }
  92
  93 /*
  94  * make the child exit.  Best I can do is send it a sigkill.
  95  * perhaps it should be put in the status that it wants to
  96  * exit.
  97  */
  98         case PTRACE_KILL: {
  99                 ret = 0;
 100                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 101                         break;
 102
 103                 set_singlestepping(child, 0);
 104                 child->exit_code = SIGKILL;
 105                 wake_up_process(child);
 106                 break;
 107         }
 108
 109         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 110                 ret = -EIO;
 111                 if (!valid_signal(data))
 112                         break;
 113                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 114                 set_singlestepping(child, 1);
 115                 child->exit_code = data;
 116                 /* give it a chance to run. */
 117                 wake_up_process(child);
 118                 ret = 0;
 119                 break;
 120         }
 121
 122         case PTRACE_DETACH:
 123                 /* detach a process that was attached. */
 124                 ret = ptrace_detach(child, data);
 125                 break;
 126
 127 #ifdef PTRACE_GETREGS
 128         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 129                 if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
 130                         ret = -EIO;
 131                         break;
 132                 }
 133                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 134                         __put_user(getreg(child, i), p);
 135                         p++;
 136                 }
 137                 ret = 0;
 138                 break;
 139         }
 140 #endif
 141 #ifdef PTRACE_SETREGS
 142         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 143                 unsigned long tmp = 0;
 144                 if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
 145                         ret = -EIO;
 146                         break;
 147                 }
 148                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 149                         __get_user(tmp, p);
 150                         putreg(child, i, tmp);
 151                         p++;
 152                 }
 153                 ret = 0;
 154                 break;
 155         }
 156 #endif
 157 #ifdef PTRACE_GETFPREGS
 158         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 159                 ret = get_fpregs(data, child);
 160                 break;
 161 #endif
 162 #ifdef PTRACE_SETFPREGS
 163         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 164                 ret = set_fpregs(data, child);
 165                 break;
 166 #endif
 167 #ifdef PTRACE_GETFPXREGS
 168         case PTRACE_GETFPXREGS: /* Get the child FPU state. */
 169                 ret = get_fpxregs(data, child);
 170                 break;
 171 #endif
 172 #ifdef PTRACE_SETFPXREGS
 173         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 174                 ret = set_fpxregs(data, child);
 175                 break;
 176 #endif
 177         case PTRACE_GET_THREAD_AREA:
 178                 ret = ptrace_get_thread_area(child, addr,
 179                                              (struct user_desc __user *) data);
 180                 break;
 181
 182         case PTRACE_SET_THREAD_AREA:
 183                 ret = ptrace_set_thread_area(child, addr,
 184                                              (struct user_desc __user *) data);
 185                 break;
 186
 187         case PTRACE_FAULTINFO: {
 188                 /* Take the info from thread->arch->faultinfo,
 189                  * but transfer max. sizeof(struct ptrace_faultinfo).
 190                  * On i386, ptrace_faultinfo is smaller!
 191                  */
 192                 ret = copy_to_user(p, &child->thread.arch.faultinfo,
 193                                    sizeof(struct ptrace_faultinfo));
 194                 if(ret)
 195                         break;
 196                 break;
 197         }
 198
 199 #ifdef PTRACE_LDT
 200         case PTRACE_LDT: {
 201                 struct ptrace_ldt ldt;
 202
 203                 if(copy_from_user(&ldt, p, sizeof(ldt))){
 204                         ret = -EIO;
 205                         break;
 206                 }
 207
 208                 /* This one is confusing, so just punt and return -EIO for
 209                  * now
 210                  */
 211                 ret = -EIO;
 212                 break;
 213         }
 214 #endif
 215 #ifdef CONFIG_PROC_MM
 216         case PTRACE_SWITCH_MM: {
 217                 struct mm_struct *old = child->mm;
 218                 struct mm_struct *new = proc_mm_get_mm(data);
 219
 220                 if(IS_ERR(new)){
 221                         ret = PTR_ERR(new);
 222                         break;
 223                 }
 224
 225                 atomic_inc(&new->mm_users);
 226                 child->mm = new;
 227                 child->active_mm = new;
 228                 mmput(old);
 229                 ret = 0;
 230                 break;
 231         }
 232 #endif
 233 #ifdef PTRACE_ARCH_PRCTL
 234         case PTRACE_ARCH_PRCTL:
 235                 /* XXX Calls ptrace on the host - needs some SMP thinking */
 236                 ret = arch_prctl_skas(child, data, (void *) addr);
 237                 break;
 238 #endif
 239         default:
 240                 ret = ptrace_request(child, request, addr, data);
 241                 break;
 242         }
 243
 244         return ret;
 245 }
 246
 247 void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
 248                   int error_code)
 249 {
 250         struct siginfo info;
 251
 252         memset(&info, 0, sizeof(info));
 253         info.si_signo = SIGTRAP;
 254         info.si_code = TRAP_BRKPT;
 255
 256         /* User-mode eip? */
 257         info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
 258
 259         /* Send us the fakey SIGTRAP */
 260         force_sig_info(SIGTRAP, &info, tsk);
 261 }
 262
 263 /* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
 264  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
 265  */
 266 void syscall_trace(union uml_pt_regs *regs, int entryexit)
 267 {
 268         int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
 269         int tracesysgood;
 270
 271         if (unlikely(current->audit_context)) {
 272                 if (!entryexit)
 273                         audit_syscall_entry(HOST_AUDIT_ARCH,
 274                                             UPT_SYSCALL_NR(regs),
 275                                             UPT_SYSCALL_ARG1(regs),
 276                                             UPT_SYSCALL_ARG2(regs),
 277                                             UPT_SYSCALL_ARG3(regs),
 278                                             UPT_SYSCALL_ARG4(regs));
 279                 else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
 280                                         UPT_SYSCALL_RET(regs));
 281         }
 282
 283         /* Fake a debug trap */
 284         if (is_singlestep)
 285                 send_sigtrap(current, regs, 0);
 286
 287         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 288                 return;
 289
 290         if (!(current->ptrace & PT_PTRACED))
 291                 return;
 292
 293         /* the 0x80 provides a way for the tracing parent to distinguish
 294            between a syscall stop and SIGTRAP delivery */
 295         tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
 296         ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
 297
 298         if (entryexit) /* force do_signal() --> is_syscall() */
 299                 set_thread_flag(TIF_SIGPENDING);
 300
 301         /* this isn't the same as continuing with a signal, but it will do
 302          * for normal use.  strace only continues with a signal if the
 303          * stopping signal is not SIGTRAP.  -brl
 304          */
 305         if (current->exit_code) {
 306                 send_sig(current->exit_code, current, 1);
 307                 current->exit_code = 0;
 308         }
 309 }