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                 unsigned long tmp;
  57                 int copied;
  58
  59                 ret = -EIO;
  60                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
  61                 if (copied != sizeof(tmp))
  62                         break;
  63                 ret = put_user(tmp, p);
  64                 break;
  65         }
  66
  67         /* read the word at location addr in the USER area. */
  68         case PTRACE_PEEKUSR:
  69                 ret = peek_user(child, addr, data);
  70                 break;
  71
  72         /* when I and D space are separate, this will have to be fixed. */
  73         case PTRACE_POKETEXT: /* write the word at location addr. */
  74         case PTRACE_POKEDATA:
  75                 ret = -EIO;
  76                 if (access_process_vm(child, addr, &data, sizeof(data),
  77                                       1) != sizeof(data))
  78                         break;
  79                 ret = 0;
  80                 break;
  81
  82         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
  83                 ret = poke_user(child, addr, data);
  84                 break;
  85
  86         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
  87         case PTRACE_CONT: { /* restart after signal. */
  88                 ret = -EIO;
  89                 if (!valid_signal(data))
  90                         break;
  91
  92                 set_singlestepping(child, 0);
  93                 if (request == PTRACE_SYSCALL) {
  94                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
  95                 }
  96                 else {
  97                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
  98                 }
  99                 child->exit_code = data;
 100                 wake_up_process(child);
 101                 ret = 0;
 102                 break;
 103         }
 104
 105 /*
 106  * make the child exit.  Best I can do is send it a sigkill.
 107  * perhaps it should be put in the status that it wants to
 108  * exit.
 109  */
 110         case PTRACE_KILL: {
 111                 ret = 0;
 112                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 113                         break;
 114
 115                 set_singlestepping(child, 0);
 116                 child->exit_code = SIGKILL;
 117                 wake_up_process(child);
 118                 break;
 119         }
 120
 121         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 122                 ret = -EIO;
 123                 if (!valid_signal(data))
 124                         break;
 125                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 126                 set_singlestepping(child, 1);
 127                 child->exit_code = data;
 128                 /* give it a chance to run. */
 129                 wake_up_process(child);
 130                 ret = 0;
 131                 break;
 132         }
 133
 134         case PTRACE_DETACH:
 135                 /* detach a process that was attached. */
 136                 ret = ptrace_detach(child, data);
 137                 break;
 138
 139 #ifdef PTRACE_GETREGS
 140         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 141                 if (!access_ok(VERIFY_WRITE, p, MAX_REG_OFFSET)) {
 142                         ret = -EIO;
 143                         break;
 144                 }
 145                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 146                         __put_user(getreg(child, i), p);
 147                         p++;
 148                 }
 149                 ret = 0;
 150                 break;
 151         }
 152 #endif
 153 #ifdef PTRACE_SETREGS
 154         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 155                 unsigned long tmp = 0;
 156                 if (!access_ok(VERIFY_READ, p, MAX_REG_OFFSET)) {
 157                         ret = -EIO;
 158                         break;
 159                 }
 160                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 161                         __get_user(tmp, p);
 162                         putreg(child, i, tmp);
 163                         p++;
 164                 }
 165                 ret = 0;
 166                 break;
 167         }
 168 #endif
 169 #ifdef PTRACE_GETFPREGS
 170         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 171                 ret = get_fpregs(data, child);
 172                 break;
 173 #endif
 174 #ifdef PTRACE_SETFPREGS
 175         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 176                 ret = set_fpregs(data, child);
 177                 break;
 178 #endif
 179 #ifdef PTRACE_GETFPXREGS
 180         case PTRACE_GETFPXREGS: /* Get the child FPU state. */
 181                 ret = get_fpxregs(data, child);
 182                 break;
 183 #endif
 184 #ifdef PTRACE_SETFPXREGS
 185         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 186                 ret = set_fpxregs(data, child);
 187                 break;
 188 #endif
 189         case PTRACE_GET_THREAD_AREA:
 190                 ret = ptrace_get_thread_area(child, addr,
 191                                              (struct user_desc __user *) data);
 192                 break;
 193
 194         case PTRACE_SET_THREAD_AREA:
 195                 ret = ptrace_set_thread_area(child, addr,
 196                                              (struct user_desc __user *) data);
 197                 break;
 198
 199         case PTRACE_FAULTINFO: {
 200                 /* Take the info from thread->arch->faultinfo,
 201                  * but transfer max. sizeof(struct ptrace_faultinfo).
 202                  * On i386, ptrace_faultinfo is smaller!
 203                  */
 204                 ret = copy_to_user(p, &child->thread.arch.faultinfo,
 205                                    sizeof(struct ptrace_faultinfo));
 206                 if(ret)
 207                         break;
 208                 break;
 209         }
 210
 211 #ifdef PTRACE_LDT
 212         case PTRACE_LDT: {
 213                 struct ptrace_ldt ldt;
 214
 215                 if(copy_from_user(&ldt, p, sizeof(ldt))){
 216                         ret = -EIO;
 217                         break;
 218                 }
 219
 220                 /* This one is confusing, so just punt and return -EIO for
 221                  * now
 222                  */
 223                 ret = -EIO;
 224                 break;
 225         }
 226 #endif
 227 #ifdef CONFIG_PROC_MM
 228         case PTRACE_SWITCH_MM: {
 229                 struct mm_struct *old = child->mm;
 230                 struct mm_struct *new = proc_mm_get_mm(data);
 231
 232                 if(IS_ERR(new)){
 233                         ret = PTR_ERR(new);
 234                         break;
 235                 }
 236
 237                 atomic_inc(&new->mm_users);
 238                 child->mm = new;
 239                 child->active_mm = new;
 240                 mmput(old);
 241                 ret = 0;
 242                 break;
 243         }
 244 #endif
 245 #ifdef PTRACE_ARCH_PRCTL
 246         case PTRACE_ARCH_PRCTL:
 247                 /* XXX Calls ptrace on the host - needs some SMP thinking */
 248                 ret = arch_prctl_skas(child, data, (void *) addr);
 249                 break;
 250 #endif
 251         default:
 252                 ret = ptrace_request(child, request, addr, data);
 253                 break;
 254         }
 255
 256         return ret;
 257 }
 258
 259 void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
 260                   int error_code)
 261 {
 262         struct siginfo info;
 263
 264         memset(&info, 0, sizeof(info));
 265         info.si_signo = SIGTRAP;
 266         info.si_code = TRAP_BRKPT;
 267
 268         /* User-mode eip? */
 269         info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
 270
 271         /* Send us the fakey SIGTRAP */
 272         force_sig_info(SIGTRAP, &info, tsk);
 273 }
 274
 275 /* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
 276  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
 277  */
 278 void syscall_trace(union uml_pt_regs *regs, int entryexit)
 279 {
 280         int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
 281         int tracesysgood;
 282
 283         if (unlikely(current->audit_context)) {
 284                 if (!entryexit)
 285                         audit_syscall_entry(HOST_AUDIT_ARCH,
 286                                             UPT_SYSCALL_NR(regs),
 287                                             UPT_SYSCALL_ARG1(regs),
 288                                             UPT_SYSCALL_ARG2(regs),
 289                                             UPT_SYSCALL_ARG3(regs),
 290                                             UPT_SYSCALL_ARG4(regs));
 291                 else audit_syscall_exit(AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
 292                                         UPT_SYSCALL_RET(regs));
 293         }
 294
 295         /* Fake a debug trap */
 296         if (is_singlestep)
 297                 send_sigtrap(current, regs, 0);
 298
 299         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 300                 return;
 301
 302         if (!(current->ptrace & PT_PTRACED))
 303                 return;
 304
 305         /* the 0x80 provides a way for the tracing parent to distinguish
 306            between a syscall stop and SIGTRAP delivery */
 307         tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
 308         ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
 309
 310         if (entryexit) /* force do_signal() --> is_syscall() */
 311                 set_thread_flag(TIF_SIGPENDING);
 312
 313         /* this isn't the same as continuing with a signal, but it will do
 314          * for normal use.  strace only continues with a signal if the
 315          * stopping signal is not SIGTRAP.  -brl
 316          */
 317         if (current->exit_code) {
 318                 send_sig(current->exit_code, current, 1);
 319                 current->exit_code = 0;
 320         }
 321 }