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 sys_ptrace(long request, long pid, long addr, long data)
  47 {
  48         struct task_struct *child;
  49         int i, ret;
  50
  51         lock_kernel();
  52         ret = -EPERM;
  53         if (request == PTRACE_TRACEME) {
  54                 /* are we already being traced? */
  55                 if (current->ptrace & PT_PTRACED)
  56                         goto out;
  57
  58                 ret = security_ptrace(current->parent, current);
  59                 if (ret)
  60                         goto out;
  61
  62                 /* set the ptrace bit in the process flags. */
  63                 current->ptrace |= PT_PTRACED;
  64                 ret = 0;
  65                 goto out;
  66         }
  67         ret = -ESRCH;
  68         read_lock(&tasklist_lock);
  69         child = find_task_by_pid(pid);
  70         if (child)
  71                 get_task_struct(child);
  72         read_unlock(&tasklist_lock);
  73         if (!child)
  74                 goto out;
  75         if (!vx_check(vx_task_xid(child), VX_WATCH|VX_IDENT))
  76                 goto out_tsk;
  77
  78         ret = -EPERM;
  79         if (pid == 1)           /* you may not mess with init */
  80                 goto out_tsk;
  81
  82         if (request == PTRACE_ATTACH) {
  83                 ret = ptrace_attach(child);
  84                 goto out_tsk;
  85         }
  86
  87 #ifdef SUBACH_PTRACE_SPECIAL
  88         SUBARCH_PTRACE_SPECIAL(child,request,addr,data);
  89 #endif
  90
  91         ret = ptrace_check_attach(child, request == PTRACE_KILL);
  92         if (ret < 0)
  93                 goto out_tsk;
  94
  95         switch (request) {
  96                 /* when I and D space are separate, these will need to be fixed. */
  97         case PTRACE_PEEKTEXT: /* read word at location addr. */
  98         case PTRACE_PEEKDATA: {
  99                 unsigned long tmp;
 100                 int copied;
 101
 102                 ret = -EIO;
 103                 copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0);
 104                 if (copied != sizeof(tmp))
 105                         break;
 106                 ret = put_user(tmp, (unsigned long __user *) data);
 107                 break;
 108         }
 109
 110         /* read the word at location addr in the USER area. */
 111         case PTRACE_PEEKUSR:
 112                 ret = peek_user(child, addr, data);
 113                 break;
 114
 115         /* when I and D space are separate, this will have to be fixed. */
 116         case PTRACE_POKETEXT: /* write the word at location addr. */
 117         case PTRACE_POKEDATA:
 118                 ret = -EIO;
 119                 if (access_process_vm(child, addr, &data, sizeof(data),
 120                                       1) != sizeof(data))
 121                         break;
 122                 ret = 0;
 123                 break;
 124
 125         case PTRACE_POKEUSR: /* write the word at location addr in the USER area */
 126                 ret = poke_user(child, addr, data);
 127                 break;
 128
 129         case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */
 130         case PTRACE_CONT: { /* restart after signal. */
 131                 ret = -EIO;
 132                 if (!valid_signal(data))
 133                         break;
 134
 135                 set_singlestepping(child, 0);
 136                 if (request == PTRACE_SYSCALL) {
 137                         set_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 138                 }
 139                 else {
 140                         clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 141                 }
 142                 child->exit_code = data;
 143                 wake_up_process(child);
 144                 ret = 0;
 145                 break;
 146         }
 147
 148 /*
 149  * make the child exit.  Best I can do is send it a sigkill.
 150  * perhaps it should be put in the status that it wants to
 151  * exit.
 152  */
 153         case PTRACE_KILL: {
 154                 ret = 0;
 155                 if (child->exit_state == EXIT_ZOMBIE)   /* already dead */
 156                         break;
 157
 158                 set_singlestepping(child, 0);
 159                 child->exit_code = SIGKILL;
 160                 wake_up_process(child);
 161                 break;
 162         }
 163
 164         case PTRACE_SINGLESTEP: {  /* set the trap flag. */
 165                 ret = -EIO;
 166                 if (!valid_signal(data))
 167                         break;
 168                 clear_tsk_thread_flag(child, TIF_SYSCALL_TRACE);
 169                 set_singlestepping(child, 1);
 170                 child->exit_code = data;
 171                 /* give it a chance to run. */
 172                 wake_up_process(child);
 173                 ret = 0;
 174                 break;
 175         }
 176
 177         case PTRACE_DETACH:
 178                 /* detach a process that was attached. */
 179                 ret = ptrace_detach(child, data);
 180                 break;
 181
 182 #ifdef PTRACE_GETREGS
 183         case PTRACE_GETREGS: { /* Get all gp regs from the child. */
 184                 if (!access_ok(VERIFY_WRITE, (unsigned long *)data,
 185                                MAX_REG_OFFSET)) {
 186                         ret = -EIO;
 187                         break;
 188                 }
 189                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 190                         __put_user(getreg(child, i),
 191                                    (unsigned long __user *) data);
 192                         data += sizeof(long);
 193                 }
 194                 ret = 0;
 195                 break;
 196         }
 197 #endif
 198 #ifdef PTRACE_SETREGS
 199         case PTRACE_SETREGS: { /* Set all gp regs in the child. */
 200                 unsigned long tmp = 0;
 201                 if (!access_ok(VERIFY_READ, (unsigned *)data,
 202                                MAX_REG_OFFSET)) {
 203                         ret = -EIO;
 204                         break;
 205                 }
 206                 for ( i = 0; i < MAX_REG_OFFSET; i += sizeof(long) ) {
 207                         __get_user(tmp, (unsigned long __user *) data);
 208                         putreg(child, i, tmp);
 209                         data += sizeof(long);
 210                 }
 211                 ret = 0;
 212                 break;
 213         }
 214 #endif
 215 #ifdef PTRACE_GETFPREGS
 216         case PTRACE_GETFPREGS: /* Get the child FPU state. */
 217                 ret = get_fpregs(data, child);
 218                 break;
 219 #endif
 220 #ifdef PTRACE_SETFPREGS
 221         case PTRACE_SETFPREGS: /* Set the child FPU state. */
 222                 ret = set_fpregs(data, child);
 223                 break;
 224 #endif
 225 #ifdef PTRACE_GETFPXREGS
 226         case PTRACE_GETFPXREGS: /* Get the child FPU state. */
 227                 ret = get_fpxregs(data, child);
 228                 break;
 229 #endif
 230 #ifdef PTRACE_SETFPXREGS
 231         case PTRACE_SETFPXREGS: /* Set the child FPU state. */
 232                 ret = set_fpxregs(data, child);
 233                 break;
 234 #endif
 235         case PTRACE_FAULTINFO: {
 236                 /* Take the info from thread->arch->faultinfo,
 237                  * but transfer max. sizeof(struct ptrace_faultinfo).
 238                  * On i386, ptrace_faultinfo is smaller!
 239                  */
 240                 ret = copy_to_user((unsigned long __user *) data,
 241                                    &child->thread.arch.faultinfo,
 242                                    sizeof(struct ptrace_faultinfo));
 243                 if(ret)
 244                         break;
 245                 break;
 246         }
 247
 248 #ifdef PTRACE_LDT
 249         case PTRACE_LDT: {
 250                 struct ptrace_ldt ldt;
 251
 252                 if(copy_from_user(&ldt, (unsigned long __user *) data,
 253                                   sizeof(ldt))){
 254                         ret = -EIO;
 255                         break;
 256                 }
 257
 258                 /* This one is confusing, so just punt and return -EIO for
 259                  * now
 260                  */
 261                 ret = -EIO;
 262                 break;
 263         }
 264 #endif
 265 #ifdef CONFIG_PROC_MM
 266         case PTRACE_SWITCH_MM: {
 267                 struct mm_struct *old = child->mm;
 268                 struct mm_struct *new = proc_mm_get_mm(data);
 269
 270                 if(IS_ERR(new)){
 271                         ret = PTR_ERR(new);
 272                         break;
 273                 }
 274
 275                 atomic_inc(&new->mm_users);
 276                 child->mm = new;
 277                 child->active_mm = new;
 278                 mmput(old);
 279                 ret = 0;
 280                 break;
 281         }
 282 #endif
 283         default:
 284                 ret = ptrace_request(child, request, addr, data);
 285                 break;
 286         }
 287  out_tsk:
 288         put_task_struct(child);
 289  out:
 290         unlock_kernel();
 291         return ret;
 292 }
 293
 294 void send_sigtrap(struct task_struct *tsk, union uml_pt_regs *regs,
 295                   int error_code)
 296 {
 297         struct siginfo info;
 298
 299         memset(&info, 0, sizeof(info));
 300         info.si_signo = SIGTRAP;
 301         info.si_code = TRAP_BRKPT;
 302
 303         /* User-mode eip? */
 304         info.si_addr = UPT_IS_USER(regs) ? (void __user *) UPT_IP(regs) : NULL;
 305
 306         /* Send us the fakey SIGTRAP */
 307         force_sig_info(SIGTRAP, &info, tsk);
 308 }
 309
 310 /* XXX Check PT_DTRACE vs TIF_SINGLESTEP for singlestepping check and
 311  * PT_PTRACED vs TIF_SYSCALL_TRACE for syscall tracing check
 312  */
 313 void syscall_trace(union uml_pt_regs *regs, int entryexit)
 314 {
 315         int is_singlestep = (current->ptrace & PT_DTRACE) && entryexit;
 316         int tracesysgood;
 317
 318         if (unlikely(current->audit_context)) {
 319                 if (!entryexit)
 320                         audit_syscall_entry(current,
 321                                             HOST_AUDIT_ARCH,
 322                                             UPT_SYSCALL_NR(regs),
 323                                             UPT_SYSCALL_ARG1(regs),
 324                                             UPT_SYSCALL_ARG2(regs),
 325                                             UPT_SYSCALL_ARG3(regs),
 326                                             UPT_SYSCALL_ARG4(regs));
 327                 else audit_syscall_exit(current,
 328                                         AUDITSC_RESULT(UPT_SYSCALL_RET(regs)),
 329                                         UPT_SYSCALL_RET(regs));
 330         }
 331
 332         /* Fake a debug trap */
 333         if (is_singlestep)
 334                 send_sigtrap(current, regs, 0);
 335
 336         if (!test_thread_flag(TIF_SYSCALL_TRACE))
 337                 return;
 338
 339         if (!(current->ptrace & PT_PTRACED))
 340                 return;
 341
 342         /* the 0x80 provides a way for the tracing parent to distinguish
 343            between a syscall stop and SIGTRAP delivery */
 344         tracesysgood = (current->ptrace & PT_TRACESYSGOOD);
 345         ptrace_notify(SIGTRAP | (tracesysgood ? 0x80 : 0));
 346
 347         if (entryexit) /* force do_signal() --> is_syscall() */
 348                 set_thread_flag(TIF_SIGPENDING);
 349
 350         /* this isn't the same as continuing with a signal, but it will do
 351          * for normal use.  strace only continues with a signal if the
 352          * stopping signal is not SIGTRAP.  -brl
 353          */
 354         if (current->exit_code) {
 355                 send_sig(current->exit_code, current, 1);
 356                 current->exit_code = 0;
 357         }
 358 }