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