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
  22 static inline void set_singlestepping(struct task_struct *child, int on)
  23 {
  24         if (on)
  25                 child->ptrace |= PT_DTRACE;
  26         else
  27                 child->ptrace &= ~PT_DTRACE;
  28         child->thread.singlestep_syscall = 0;
  29
  30 #ifdef SUBARCH_SET_SINGLESTEPPING
  31         SUBARCH_SET_SINGLESTEPPING(child, on);
  32 #endif
  33 }
  34
  35 /*
  36  * Called by kernel/ptrace.c when detaching..
  37  */
  38 void ptrace_disable(struct task_struct *child)
  39 {
  40         set_singlestepping(child,0);
  41 }
  42
  43 extern int peek_user(struct task_struct * child, long addr, long data);
  44 extern int poke_user(struct task_struct * child, long addr, long data);
  45
  46 long arch_ptrace(struct task_struct *child, long request, long addr, long data)
  47 {
  48         int i, ret;
  49         unsigned long __user *p = (void __user *)(unsigned long)data;
  50
  51         switch (request) {
  52                 /* when I and D space are separate, these will need to be fixed. */
  53         case PTRACE_PEEKTEXT: /* read word at location addr. */
  54         case PTRACE_PEEKDATA: {
  55                 unsigned long tmp;
  56                 int copied;
  57
  58                 ret = -EIO;
  59                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
  60                 if (copied != sizeof(tmp))
  61                         break;
  62                 ret = put_user(tmp, p);
  63                 break;
  64         }
  65
  66         /* read the word at location addr in the USER area. */
  67         case PTRACE_PEEKUSR:
  68                 ret = peek_user(child, addr, data);
  69                 break;
  70
  71         /* when I and D space are separate, this will have to be fixed. */
  72         case PTRACE_POKETEXT: /* write the word at location addr. */
  73         case PTRACE_POKEDATA:
  74                 ret = -EIO;
  75                 if (access_process_vm(child, addr, &data, sizeof(data),
  76                                       1) != sizeof(data))
  77                         break;
  78                 ret = 0;
  79                 break;
  80
  81         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
  82                 ret = poke_user(child, addr, data);
  83                 break;
  84
  85         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
  86         case PTRACE_CONT: { /* restart after signal. */
  87                 ret = -EIO;
  88                 if (!valid_signal(data))
  89                         break;
  90
  91                 set_singlestepping(child, 0);
  92                 if (request == PTRACE_SYSCALL) {
  93                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
  94                 }
  95                 else {
  96                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
  97                 }
  98                 child->exit_code = data;
  99                 wake_up_process(child);
 100                 ret = 0;
 101                 break;
 102         }
 103
 104 /*
 105  * make the child exit.  Best I can do is send it a sigkill.
 106  * perhaps it should be put in the status that it wants to
 107  * exit.
 108  */
 109         case PTRACE_KILL: {
 110                 ret = 0;
 111                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 112                         break;
 113
 114                 set_singlestepping(child, 0);
 115                 child->exit_code = SIGKILL;
 116                 wake_up_process(child);
 117                 break;
 118         }
 119
 120         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 121                 ret = -EIO;
 122                 if (!valid_signal(data))
 123                         break;
 124                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 125                 set_singlestepping(child, 1);
 126                 child->exit_code = data;
 127                 /* give it a chance to run. */
 128                 wake_up_process(child);
 129                 ret = 0;
 130                 break;
 131         }
 132
 133         case PTRACE_DETACH:
 134                 /* detach a process that was attached. */
 135                 ret = ptrace_detach(child, data);
 136                 break;
 137
 138 #ifdef PTRACE_GETREGS
 139         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 140                 if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
 141                         ret = -EIO;
 142                         break;
 143                 }
 144                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 145                         __put_user(getreg(child, i), p);
 146                         p++;
 147                 }
 148                 ret = 0;
 149                 break;
 150         }
 151 #endif
 152 #ifdef PTRACE_SETREGS
 153         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 154                 unsigned long tmp = 0;
 155                 if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
 156                         ret = -EIO;
 157                         break;
 158                 }
 159                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 160                         __get_user(tmp, p);
 161                         putreg(child, i, tmp);
 162                         p++;
 163                 }
 164                 ret = 0;
 165                 break;
 166         }
 167 #endif
 168 #ifdef PTRACE_GETFPREGS
 169         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 170                 ret = get_fpregs(data, child);
 171                 break;
 172 #endif
 173 #ifdef PTRACE_SETFPREGS
 174         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 175                 ret = set_fpregs(data, child);
 176                 break;
 177 #endif
 178 #ifdef PTRACE_GETFPXREGS
 179         case PTRACE_GETFPXREGS: /* Get the child FPU state. */
 180                 ret = get_fpxregs(data, child);
 181                 break;
 182 #endif
 183 #ifdef PTRACE_SETFPXREGS
 184         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 185                 ret = set_fpxregs(data, child);
 186                 break;
 187 #endif
 188         case PTRACE_GET_THREAD_AREA:
 189                 ret = ptrace_get_thread_area(child, addr,
 190                                              (struct user_desc __user *) data);
 191                 break;
 192
 193         case PTRACE_SET_THREAD_AREA:
 194                 ret = ptrace_set_thread_area(child, addr,
 195                                              (struct user_desc __user *) data);
 196                 break;
 197
 198         case PTRACE_FAULTINFO: {
 199                 /* Take the info from thread->arch->faultinfo,
 200                  * but transfer max. sizeof(struct ptrace_faultinfo).
 201                  * On i386, ptrace_faultinfo is smaller!
 202                  */
 203                 ret = copy_to_user(p, &child->thread.arch.faultinfo,
 204                                    sizeof(struct ptrace_faultinfo));
 205                 if(ret)
 206                         break;
 207                 break;
 208         }
 209
 210 #ifdef PTRACE_LDT
 211         case PTRACE_LDT: {
 212                 struct ptrace_ldt ldt;
 213
 214                 if(copy_from_user(&ldt, p, sizeof(ldt))){
 215                         ret = -EIO;
 216                         break;
 217                 }
 218
 219                 /* This one is confusing, so just punt and return -EIO for
 220                  * now
 221                  */
 222                 ret = -EIO;
 223                 break;
 224         }
 225 #endif
 226 #ifdef CONFIG_PROC_MM
 227         case PTRACE_SWITCH_MM: {
 228                 struct mm_struct *old = child->mm;
 229                 struct mm_struct *new = proc_mm_get_mm(data);
 230
 231                 if(IS_ERR(new)){
 232                         ret = PTR_ERR(new);
 233                         break;
 234                 }
 235
 236                 atomic_inc(&new->mm_users);
 237                 child->mm = new;
 238                 child->active_mm = new;
 239                 mmput(old);
 240                 ret = 0;
 241                 break;
 242         }
 243 #endif
 244         default:
 245                 ret = ptrace_request(child, request, addr, data);
 246                 break;
 247         }
 248
 249         return ret;
 250 }
 251
 252 void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
 253                   int error_code)
 254 {
 255         struct siginfo info;
 256
 257         memset(&info, 0, sizeof(info));
 258         info.si_signo = SIGTRAP;
 259         info.si_code = TRAP_BRKPT;
 260
 261         /* User-mode eip? */
 262         info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
 263
 264         /* Send us the fakey SIGTRAP */
 265         force_sig_info(SIGTRAP, &info, tsk);
 266 }
 267
 268 /* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
 269  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
 270  */
 271 void syscall_trace(union uml_pt_regs *regs, int entryexit)
 272 {
 273         int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
 274         int tracesysgood;
 275
 276         if (unlikely(current->audit_context)) {
 277                 if (!entryexit)
 278                         audit_syscall_entry(HOST_AUDIT_ARCH,
 279                                             UPT_SYSCALL_NR(regs),
 280                                             UPT_SYSCALL_ARG1(regs),
 281                                             UPT_SYSCALL_ARG2(regs),
 282                                             UPT_SYSCALL_ARG3(regs),
 283                                             UPT_SYSCALL_ARG4(regs));
 284                 else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
 285                                         UPT_SYSCALL_RET(regs));
 286         }
 287
 288         /* Fake a debug trap */
 289         if (is_singlestep)
 290                 send_sigtrap(current, regs, 0);
 291
 292         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 293                 return;
 294
 295         if (!(current->ptrace & PT_PTRACED))
 296                 return;
 297
 298         /* the 0x80 provides a way for the tracing parent to distinguish
 299            between a syscall stop and SIGTRAP delivery */
 300         tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
 301         ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
 302
 303         if (entryexit) /* force do_signal() --> is_syscall() */
 304                 set_thread_flag(TIF_SIGPENDING);
 305
 306         /* this isn't the same as continuing with a signal, but it will do
 307          * for normal use.  strace only continues with a signal if the
 308          * stopping signal is not SIGTRAP.  -brl
 309          */
 310         if (current->exit_code) {
 311                 send_sig(current->exit_code, current, 1);
 312                 current->exit_code = 0;
 313         }
 314 }