server/context_i386.c

   1 /*
   2  * i386 register context support
   3  *
   4  * Copyright (C) 1999 Alexandre Julliard
   5  */
   6
   7 #include "config.h"
   8
   9 #ifdef __i386__
  10
  11 #include <assert.h>
  12 #include <errno.h>
  13 #include <sys/ptrace.h>
  14 #include <sys/user.h>
  15
  16 #include "winbase.h"
  17
  18 #include "thread.h"
  19 #include "request.h"
  20
  21
  22 #ifndef PTRACE_PEEKUSER
  23 #define PTRACE_PEEKUSER PT_READ_U
  24 #endif
  25 #ifndef PTRACE_POKEUSER
  26 #define PTRACE_POKEUSER PT_WRITE_U
  27 #endif
  28 #ifndef PTRACE_GETREGS
  29 #define PTRACE_GETREGS PT_GETREGS
  30 #endif
  31 #ifndef PTRACE_GETFPREGS
  32 #define PTRACE_GETFPREGS PT_GETFPREGS
  33 #endif
  34
  35 #ifdef linux
  36
  37 /* user_regs definitions from asm/user.h */
  38 struct kernel_user_regs_struct
  39 {
  40     long ebx, ecx, edx, esi, edi, ebp, eax;
  41     unsigned short ds, __ds, es, __es;
  42     unsigned short fs, __fs, gs, __gs;
  43     long orig_eax, eip;
  44     unsigned short cs, __cs;
  45     long eflags, esp;
  46     unsigned short ss, __ss;
  47 };
  48
  49 /* debug register offset in struct user */
  50 #define DR_OFFSET(dr) ((int)((((struct user *)0)->u_debugreg) + (dr)))
  51
  52 /* retrieve a debug register */
  53 static inline int get_debug_reg( int pid, int num, DWORD *data )
  54 {
  55     int res = ptrace( PTRACE_PEEKUSER, pid, DR_OFFSET(num), 0 );
  56     if ((res == -1) && errno)
  57     {
  58         file_set_error();
  59         return -1;
  60     }
  61     *data = res;
  62     return 0;
  63 }
  64
  65 /* retrieve a thread context */
  66 static void get_thread_context( struct thread *thread, unsigned int flags, CONTEXT *context )
  67 {
  68     int pid = thread->unix_pid;
  69     if (flags & CONTEXT_FULL)
  70     {
  71         struct kernel_user_regs_struct regs;
  72         if (ptrace( PTRACE_GETREGS, pid, 0, &regs ) == -1) goto error;
  73         if (flags & CONTEXT_INTEGER)
  74         {
  75             context->Eax = regs.eax;
  76             context->Ebx = regs.ebx;
  77             context->Ecx = regs.ecx;
  78             context->Edx = regs.edx;
  79             context->Esi = regs.esi;
  80             context->Edi = regs.edi;
  81         }
  82         if (flags & CONTEXT_CONTROL)
  83         {
  84             context->Ebp    = regs.ebp;
  85             context->Esp    = regs.esp;
  86             context->Eip    = regs.eip;
  87             context->SegCs  = regs.cs;
  88             context->SegSs  = regs.ss;
  89             context->EFlags = regs.eflags;
  90         }
  91         if (flags & CONTEXT_SEGMENTS)
  92         {
  93             context->SegDs = regs.ds;
  94             context->SegEs = regs.es;
  95             context->SegFs = regs.fs;
  96             context->SegGs = regs.gs;
  97         }
  98     }
  99     if (flags & CONTEXT_DEBUG_REGISTERS)
 100     {
 101         if (get_debug_reg( pid, 0, &context->Dr0 ) == -1) goto error;
 102         if (get_debug_reg( pid, 1, &context->Dr1 ) == -1) goto error;
 103         if (get_debug_reg( pid, 2, &context->Dr2 ) == -1) goto error;
 104         if (get_debug_reg( pid, 3, &context->Dr3 ) == -1) goto error;
 105         if (get_debug_reg( pid, 6, &context->Dr6 ) == -1) goto error;
 106         if (get_debug_reg( pid, 7, &context->Dr7 ) == -1) goto error;
 107     }
 108     if (flags & CONTEXT_FLOATING_POINT)
 109     {
 110         /* we can use context->FloatSave directly as it is using the */
 111         /* correct structure (the same as fsave/frstor) */
 112         if (ptrace( PTRACE_GETFPREGS, pid, 0, &context->FloatSave ) == -1) goto error;
 113         context->FloatSave.Cr0NpxState = 0;  /* FIXME */
 114     }
 115     return;
 116  error:
 117     file_set_error();
 118 }
 119
 120
 121 /* set a thread context */
 122 static void set_thread_context( struct thread *thread, unsigned int flags, CONTEXT *context )
 123 {
 124     int pid = thread->unix_pid;
 125     if (flags & CONTEXT_FULL)
 126     {
 127         struct kernel_user_regs_struct regs;
 128         if ((flags & CONTEXT_FULL) != CONTEXT_FULL)  /* need to preserve some registers */
 129         {
 130             if (ptrace( PTRACE_GETREGS, pid, 0, &regs ) == -1) goto error;
 131         }
 132         if (flags & CONTEXT_INTEGER)
 133         {
 134             regs.eax = context->Eax;
 135             regs.ebx = context->Ebx;
 136             regs.ecx = context->Ecx;
 137             regs.edx = context->Edx;
 138             regs.esi = context->Esi;
 139             regs.edi = context->Edi;
 140         }
 141         if (flags & CONTEXT_CONTROL)
 142         {
 143             regs.ebp = context->Ebp;
 144             regs.esp = context->Esp;
 145             regs.eip = context->Eip;
 146             regs.cs  = context->SegCs;
 147             regs.ss  = context->SegSs;
 148             regs.eflags = context->EFlags;
 149         }
 150         if (flags & CONTEXT_SEGMENTS)
 151         {
 152             regs.ds = context->SegDs;
 153             regs.es = context->SegEs;
 154             regs.fs = context->SegFs;
 155             regs.gs = context->SegGs;
 156         }
 157         if (ptrace( PTRACE_SETREGS, pid, 0, &regs ) == -1) goto error;
 158     }
 159     if (flags & CONTEXT_DEBUG_REGISTERS)
 160     {
 161         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(0), context->Dr0 ) == -1) goto error;
 162         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(1), context->Dr1 ) == -1) goto error;
 163         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(2), context->Dr2 ) == -1) goto error;
 164         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(3), context->Dr3 ) == -1) goto error;
 165         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(6), context->Dr6 ) == -1) goto error;
 166         if (ptrace( PTRACE_POKEUSER, pid, DR_OFFSET(7), context->Dr7 ) == -1) goto error;
 167     }
 168     if (flags & CONTEXT_FLOATING_POINT)
 169     {
 170         /* we can use context->FloatSave directly as it is using the */
 171         /* correct structure (the same as fsave/frstor) */
 172         if (ptrace( PTRACE_SETFPREGS, pid, 0, &context->FloatSave ) == -1) goto error;
 173         context->FloatSave.Cr0NpxState = 0;  /* FIXME */
 174     }
 175     return;
 176  error:
 177     file_set_error();
 178 }
 179
 180 #else  /* linux */
 181 #error You must implement get/set_thread_context for your platform
 182 #endif  /* linux */
 183
 184
 185 /* copy a context structure according to the flags */
 186 static void copy_context( CONTEXT *to, CONTEXT *from, int flags )
 187 {
 188     if (flags & CONTEXT_CONTROL)
 189     {
 190         to->Ebp    = from->Ebp;
 191         to->Eip    = from->Eip;
 192         to->Esp    = from->Esp;
 193         to->SegCs  = from->SegCs;
 194         to->SegSs  = from->SegSs;
 195         to->EFlags = from->EFlags;
 196     }
 197     if (flags & CONTEXT_INTEGER)
 198     {
 199         to->Eax = from->Eax;
 200         to->Ebx = from->Ebx;
 201         to->Ecx = from->Ecx;
 202         to->Edx = from->Edx;
 203         to->Esi = from->Esi;
 204         to->Edi = from->Edi;
 205     }
 206     if (flags & CONTEXT_SEGMENTS)
 207     {
 208         to->SegDs = from->SegDs;
 209         to->SegEs = from->SegEs;
 210         to->SegFs = from->SegFs;
 211         to->SegGs = from->SegGs;
 212     }
 213     if (flags & CONTEXT_DEBUG_REGISTERS)
 214     {
 215         to->Dr0 = from->Dr0;
 216         to->Dr1 = from->Dr1;
 217         to->Dr2 = from->Dr2;
 218         to->Dr3 = from->Dr3;
 219         to->Dr6 = from->Dr6;
 220         to->Dr7 = from->Dr7;
 221     }
 222     if (flags & CONTEXT_FLOATING_POINT)
 223     {
 224         to->FloatSave = from->FloatSave;
 225     }
 226 }
 227
 228 /* retrieve the current context of a thread */
 229 DECL_HANDLER(get_thread_context)
 230 {
 231     struct thread *thread;
 232     CONTEXT *context;
 233
 234     if ((thread = get_thread_from_handle( req->handle, THREAD_GET_CONTEXT )))
 235     {
 236         if ((context = get_debug_context( thread )))  /* thread is inside an exception event */
 237         {
 238             copy_context( &req->context, context, req->flags );
 239         }
 240         else
 241         {
 242             suspend_thread( thread, 0 );
 243             if (thread->attached) get_thread_context( thread, req->flags, &req->context );
 244             else set_error( STATUS_ACCESS_DENIED );
 245             resume_thread( thread );
 246         }
 247         release_object( thread );
 248     }
 249 }
 250
 251
 252 /* set the current context of a thread */
 253 DECL_HANDLER(set_thread_context)
 254 {
 255     struct thread *thread;
 256     CONTEXT *context;
 257
 258     if ((thread = get_thread_from_handle( req->handle, THREAD_SET_CONTEXT )))
 259     {
 260         if ((context = get_debug_context( thread )))  /* thread is inside an exception event */
 261         {
 262             copy_context( context, &req->context, req->flags );
 263         }
 264         else
 265         {
 266             suspend_thread( thread, 0 );
 267             if (thread->attached) set_thread_context( thread, req->flags, &req->context );
 268             else set_error( STATUS_ACCESS_DENIED );
 269             resume_thread( thread );
 270         }
 271         release_object( thread );
 272     }
 273 }
 274
 275 #endif  /* __i386__ */