loader/elf.c

   1 /*
   2  *      UNIX dynamic loader
   3  *
   4  * Currently only supports stuff using the dl* API.
   5  *
   6  * Copyright 1998 Marcus Meissner
   7  *
   8  * This library is free software; you can redistribute it and/or
   9  * modify it under the terms of the GNU Lesser General Public
  10  * License as published by the Free Software Foundation; either
  11  * version 2.1 of the License, or (at your option) any later version.
  12  *
  13  * This library is distributed in the hope that it will be useful,
  14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16  * Lesser General Public License for more details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with this library; if not, write to the Free Software
  20  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21  *
  22  * FIXME:       Small reentrancy problem.
  23  * IDEA(s):     could be used to split up shell32,comctl32...
  24  */
  25
  26 #include "config.h"
  27 #include "wine/port.h"
  28
  29 #include <assert.h>
  30 #include <stdio.h>
  31 #include <string.h>
  32 #include <sys/types.h>
  33
  34 #include "snoop.h"
  35 #include "file.h"
  36 #include "module.h"
  37 #include "wine/debug.h"
  38 #include "winerror.h"
  39
  40 WINE_DEFAULT_DEBUG_CHANNEL(win32);
  41
  42 typedef struct {
  43         WORD    popl    WINE_PACKED;    /* 0x8f 0x05 */
  44         DWORD   addr_popped WINE_PACKED;/* ...  */
  45         BYTE    pushl1  WINE_PACKED;    /* 0x68 */
  46         DWORD   newret WINE_PACKED;     /* ...  */
  47         BYTE    pushl2  WINE_PACKED;    /* 0x68 */
  48         DWORD   origfun WINE_PACKED;    /* original function */
  49         BYTE    ret1    WINE_PACKED;    /* 0xc3 */
  50         WORD    addesp  WINE_PACKED;    /* 0x83 0xc4 */
  51         BYTE    nrofargs WINE_PACKED;   /* nr of arguments to add esp, */
  52         BYTE    pushl3  WINE_PACKED;    /* 0x68 */
  53         DWORD   oldret  WINE_PACKED;    /* Filled out from popl above  */
  54         BYTE    ret2    WINE_PACKED;    /* 0xc3 */
  55 } ELF_STDCALL_STUB;
  56
  57 #define UNIX_DLL_ENDING         "so"
  58
  59 #define STUBSIZE                4095
  60 #define STUBOFFSET  (sizeof(IMAGE_DOS_HEADER) + \
  61                      sizeof(IMAGE_NT_HEADERS) + \
  62                      sizeof(IMAGE_SECTION_HEADER))
  63
  64 static FARPROC ELF_FindExportedFunction( WINE_MODREF *wm, LPCSTR funcName, BOOL snoop );
  65
  66 static HMODULE ELF_CreateDummyModule( LPCSTR libname, LPCSTR modname )
  67 {
  68         PIMAGE_DOS_HEADER       dh;
  69         PIMAGE_NT_HEADERS       nth;
  70         PIMAGE_SECTION_HEADER   sh;
  71         HMODULE hmod;
  72
  73         hmod = (HMODULE)HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY,
  74                                      sizeof(IMAGE_DOS_HEADER) +
  75                                      sizeof(IMAGE_NT_HEADERS) +
  76                                      sizeof(IMAGE_SECTION_HEADER) + STUBSIZE );
  77         dh = (PIMAGE_DOS_HEADER)hmod;
  78         dh->e_magic = IMAGE_DOS_SIGNATURE;
  79         dh->e_lfanew = sizeof(IMAGE_DOS_HEADER);
  80         nth = PE_HEADER(hmod);
  81         nth->Signature = IMAGE_NT_SIGNATURE;
  82         nth->FileHeader.Machine = IMAGE_FILE_MACHINE_I386;
  83         nth->FileHeader.NumberOfSections = 1;
  84         nth->FileHeader.SizeOfOptionalHeader = sizeof(IMAGE_OPTIONAL_HEADER);
  85         nth->FileHeader.Characteristics =
  86                 IMAGE_FILE_RELOCS_STRIPPED|IMAGE_FILE_LINE_NUMS_STRIPPED|
  87                 IMAGE_FILE_LOCAL_SYMS_STRIPPED|IMAGE_FILE_32BIT_MACHINE|
  88                 IMAGE_FILE_DLL|IMAGE_FILE_DEBUG_STRIPPED;
  89         nth->OptionalHeader.Magic = IMAGE_NT_OPTIONAL_HDR_MAGIC;
  90         nth->OptionalHeader.SizeOfCode = 0;
  91         nth->OptionalHeader.SizeOfInitializedData = 0;
  92         nth->OptionalHeader.SizeOfUninitializedData = 0;
  93         nth->OptionalHeader.AddressOfEntryPoint = 0;
  94         nth->OptionalHeader.BaseOfCode          = 0;
  95         nth->OptionalHeader.MajorOperatingSystemVersion = 4;
  96         nth->OptionalHeader.MajorImageVersion   = 4;
  97         nth->OptionalHeader.SizeOfImage         = 0;
  98         nth->OptionalHeader.SizeOfHeaders       = 0;
  99         nth->OptionalHeader.Subsystem           = IMAGE_SUBSYSTEM_NATIVE;
 100         nth->OptionalHeader.DllCharacteristics  = 0;
 101         nth->OptionalHeader.NumberOfRvaAndSizes = 0;
 102
 103         /* allocate one code section that crosses the whole process range
 104          * (we could find out from internal tables ... hmm )
 105          */
 106         sh=(PIMAGE_SECTION_HEADER)(nth+1);
 107         strcpy(sh->Name,".text");
 108         sh->Misc.VirtualSize    = STUBSIZE;
 109         sh->VirtualAddress      = STUBOFFSET; /* so snoop can use it ... */
 110         sh->SizeOfRawData       = STUBSIZE;
 111         sh->PointerToRawData    = 0;
 112         sh->Characteristics     = IMAGE_SCN_CNT_CODE|IMAGE_SCN_CNT_INITIALIZED_DATA|IMAGE_SCN_MEM_EXECUTE|IMAGE_SCN_MEM_READ;
 113         return hmod;
 114 }
 115
 116 WINE_MODREF *ELF_LoadLibraryExA( LPCSTR libname, DWORD flags)
 117 {
 118         WINE_MODREF     *wm;
 119         HMODULE         hmod;
 120         char            *modname,*s,*t,*x;
 121         LPVOID          *dlhandle;
 122         char            error[256];
 123
 124         t = HeapAlloc( GetProcessHeap(), HEAP_ZERO_MEMORY,
 125                        strlen(libname) + strlen("lib.so") + 1 );
 126         *t = '\0';
 127         /* copy path to tempvar ... */
 128         s=strrchr(libname,'/');
 129         if (!s)
 130                 s=strrchr(libname,'\\');
 131         if (s) {
 132                 s++; /* skip / or \ */
 133                 /* copy everything up to s-1 */
 134                 memcpy(t,libname,s-libname);
 135                 t[s-libname]= '\0';
 136         } else
 137                 s = (LPSTR)libname;
 138         modname = s;
 139         /* append "lib" foo ".so" */
 140         strcat(t,"lib");
 141         x = t+strlen(t);
 142         strcat(t,s);
 143         s = strchr(x,'.');
 144         if (s) {
 145             while (s) {
 146                 if (!FILE_strcasecmp(s,".dll")) {
 147                     strcpy(s+1,UNIX_DLL_ENDING);
 148                     break;
 149                 }
 150                 s=strchr(s+1,'.');
 151             }
 152         } else {
 153                 strcat(x,"."UNIX_DLL_ENDING);
 154         }
 155
 156         /* grab just the last piece of the path/filename
 157            which should be the name of the library we are
 158            looking to load. increment by 1 to skip the DOS slash */
 159         s = strrchr(t,'\\');
 160         s++;
 161
 162        /* ... and open the library pointed by s, while t points
 163          points to the ENTIRE DOS filename of the library
 164          t is returned by HeapAlloc() above and so is also used
 165          with HeapFree() below */
 166         dlhandle = wine_dlopen(s,RTLD_NOW,error,sizeof(error));
 167         if (!dlhandle) {
 168                 WARN("failed to load %s: %s\n", s, error);
 169                 HeapFree( GetProcessHeap(), 0, t );
 170                 SetLastError( ERROR_FILE_NOT_FOUND );
 171                 return NULL;
 172         }
 173
 174         hmod = ELF_CreateDummyModule( t, modname );
 175
 176         SNOOP_RegisterDLL(hmod,libname,0,STUBSIZE/sizeof(ELF_STDCALL_STUB));
 177
 178         wm = PE_CreateModule( hmod, libname, 0, 0, FALSE );
 179         wm->find_export = ELF_FindExportedFunction;
 180         wm->dlhandle = dlhandle;
 181         return wm;
 182 }
 183
 184 static FARPROC ELF_FindExportedFunction( WINE_MODREF *wm, LPCSTR funcName, BOOL snoop )
 185 {
 186         LPVOID                  fun;
 187         int                     i,nrofargs = 0;
 188         ELF_STDCALL_STUB        *stub, *first_stub;
 189         char                    error[256];
 190
 191         if (!HIWORD(funcName)) {
 192                 ERR("Can't import from UNIX dynamic libs by ordinal, sorry.\n");
 193                 return (FARPROC)0;
 194         }
 195         fun = wine_dlsym(wm->dlhandle,funcName,error,sizeof(error));
 196         if (!fun)
 197         {
 198             /* we sometimes have an excess '_' at the beginning of the name */
 199             if (funcName[0]=='_')
 200             {
 201                 funcName++ ;
 202                 fun = wine_dlsym(wm->dlhandle,funcName,error,sizeof(error));
 203             }
 204         }
 205         if (!fun) {
 206                 /* Function@nrofargs usually marks a stdcall function
 207                  * with nrofargs bytes that are popped at the end
 208                  */
 209             LPCSTR t;
 210             if ((t = strchr(funcName,'@')))
 211             {
 212                 LPSTR fn = HeapAlloc( GetProcessHeap(), 0, t - funcName + 1 );
 213                 memcpy( fn, funcName, t - funcName );
 214                 fn[t - funcName] = 0;
 215                 nrofargs = 0;
 216                 sscanf(t+1,"%d",&nrofargs);
 217                 fun = wine_dlsym(wm->dlhandle,fn,error,sizeof(error));
 218                 HeapFree( GetProcessHeap(), 0, fn );
 219             }
 220         }
 221         /* We sometimes have Win32 dlls implemented using stdcall but UNIX
 222          * dlls using cdecl. If we find out the number of args the function
 223          * uses, we remove them from the stack using two small stubs.
 224          */
 225         stub = first_stub = (ELF_STDCALL_STUB *)((char *)wm->module + STUBOFFSET);
 226         for (i=0;i<STUBSIZE/sizeof(ELF_STDCALL_STUB);i++) {
 227                 if (!stub->origfun)
 228                         break;
 229                 if (stub->origfun == (DWORD)fun)
 230                         break;
 231                 stub++;
 232         }
 233         if (i==STUBSIZE/sizeof(ELF_STDCALL_STUB)) {
 234                 ERR("please report, that there are not enough slots for stdcall stubs in the ELF loader.\n");
 235                 assert(i<STUBSIZE/sizeof(ELF_STDCALL_STUB));
 236         }
 237         if (!stub->origfun)
 238                 stub->origfun=(DWORD)fun; /* just a marker */
 239
 240         if (fun && nrofargs) { /* we don't need it for 0 args */
 241                 /* Selfmodifying entry/return stub for stdcall -> cdecl
 242                  * conversion.
 243                  *  - Pop returnaddress directly into our return code
 244                  *              popl <into code below>
 245                  *  - Replace it by pointer to start of our returncode
 246                  *              push $newret
 247                  *  - And call the original function
 248                  *              jmp $orgfun
 249                  *  - Remove the arguments no longer needed
 250                  * newret:      add esp, <nrofargs>
 251                  *  - Push the original returnvalue on the stack
 252                  *              pushl <poppedvalue>
 253                  *  - And return to it.
 254                  *              ret
 255                  */
 256
 257                 /* FIXME: The function stub is not reentrant. */
 258
 259                 ((LPBYTE)&(stub->popl))[0]        = 0x8f;
 260                 ((LPBYTE)&(stub->popl))[1]        = 0x05;
 261                 stub->addr_popped = (DWORD)&(stub->oldret);
 262                 stub->pushl1      = 0x68;
 263                 stub->newret      = (DWORD)&(stub->addesp);
 264                 stub->pushl2      = 0x68;
 265                 stub->origfun     = (DWORD)fun;
 266                 stub->ret1        = 0xc3;
 267                 ((LPBYTE)&(stub->addesp))[0]=0x83;
 268                 ((LPBYTE)&(stub->addesp))[1]=0xc4;
 269                 stub->nrofargs    = nrofargs;
 270                 stub->pushl3      = 0x68;
 271                         /* filled out by entrycode */
 272                 stub->oldret      = 0xdeadbeef;
 273                 stub->ret2        = 0xc3;
 274                 fun=(FARPROC)stub;
 275         }
 276         if (!fun) {
 277                 FIXME("function %s not found: %s\n",funcName,error);
 278                 return fun;
 279         }
 280         fun = SNOOP_GetProcAddress(wm->module,funcName,stub-first_stub,fun);
 281         return (FARPROC)fun;
 282 }