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