src/runtime/ppc-darwin-dlshim.c

   1 /*
   2  * These functions emulate a small subset of the dlopen / dlsym
   3  * functionality under Darwin's Mach-O dyld system.
   4  */
   5
   6 /*
   7  * This software is part of the SBCL system. See the README file for
   8  * more information.
   9  *
  10  * This software is derived from the CMU CL system, which was
  11  * written at Carnegie Mellon University and released into the
  12  * public domain. The software is in the public domain and is
  13  * provided with absolutely no warranty. See the COPYING and CREDITS
  14  * files for more information.
  15  */
  16
  17
  18 #include <mach-o/dyld.h>
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22 #include "ppc-darwin-dlshim.h"
  23
  24 /* Darwin does not define the standard ELF
  25  * dlopen/dlclose/dlsym/dlerror interface to shared libraries, so this
  26  * is an attempt at a minimal wrapper to allow SBCL to work without
  27  * external dependency on pogma's dlcompat library.
  28  */
  29
  30 /* For now, there is no RTLD_GLOBAL emulation either. */
  31
  32 static char dl_self; /* I'm going to abuse this */
  33
  34 static int callback_count;
  35 static struct mach_header* last_header;
  36
  37 #define DLSYM_ERROR 1
  38 #define DLOPEN_ERROR 2
  39
  40 static int last_error = 0;
  41
  42 void
  43 dlshim_image_callback(struct mach_header* ptr, unsigned long phooey)
  44 {
  45     callback_count++;
  46     last_header = ptr;
  47 }
  48
  49 int
  50 lib_path_count(void)
  51 {
  52     char* libpath;
  53     int i;
  54     int count;
  55     libpath = getenv("DYLD_LIBRARY_PATH");
  56     count = 1;
  57     if (libpath) {
  58         for (i = 0; libpath[i] != '\0'; i++) {
  59             if (libpath[i] == ':') count++;
  60         }
  61     }
  62     return count;
  63 }
  64
  65 const char*
  66 lib_path_prefixify(int index, const char* filename)
  67 {
  68     static char* retbuf = NULL;
  69     int fi, li, i, count;
  70     char* libpath;
  71     if (!retbuf) {
  72         retbuf = (char*) malloc(1024*sizeof(char));
  73     }
  74     count = 0;
  75     fi = 0;
  76     li = -1;
  77     libpath = getenv("DYLD_LIBRARY_PATH");
  78     if (libpath) {
  79         i = 0;
  80         while (count != index && libpath[i] != '\0') {
  81             if (libpath[i] == ':') count++;
  82             i++;
  83         }
  84         fi = i;
  85         while (libpath[i] != '\0' && libpath[i] != ':') {
  86             i++;
  87         }
  88         li = i - 1;
  89     }
  90     if (li - fi > 0) {
  91         if (li - fi + 1 > 1022 - strlen(filename)) {
  92             retbuf =
  93                 (char*) realloc(retbuf, (li - fi + 3 + strlen(filename))*sizeof(char));
  94         }
  95         memcpy(retbuf, libpath + fi, (li - fi + 1)*sizeof(char));
  96         retbuf[li - fi + 1] = '/';
  97         memcpy(retbuf + li - fi + 2, filename, strlen(filename) + 1);
  98         return retbuf;
  99     } else {
 100         return filename;
 101     }
 102 }
 103
 104 const void*
 105 dlopen(const char* filename, int flags)
 106 {
 107     static char has_callback = 0;
 108     if (!has_callback) {
 109         _dyld_register_func_for_add_image(dlshim_image_callback);
 110     }
 111     if (!filename) {
 112         return &dl_self;
 113     } else {
 114         const struct mach_header* img = NULL;
 115         if (!img)
 116             img = NSAddImage(filename, NSADDIMAGE_OPTION_RETURN_ON_ERROR);
 117         if (!img)
 118             img = NSAddImage(filename,
 119                              NSADDIMAGE_OPTION_RETURN_ON_ERROR |
 120                              NSADDIMAGE_OPTION_WITH_SEARCHING);
 121         if (!img) {
 122             NSObjectFileImage fileImage;
 123             callback_count = 0;
 124             last_header = NULL;
 125             if (NSCreateObjectFileImageFromFile(filename, &fileImage)
 126                 == NSObjectFileImageSuccess) {
 127                 NSLinkModule(fileImage, filename,
 128                              NSLINKMODULE_OPTION_BINDNOW |
 129                              ((flags & RTLD_GLOBAL)?NSLINKMODULE_OPTION_PRIVATE:0) |
 130                              NSLINKMODULE_OPTION_RETURN_ON_ERROR);
 131                 if (callback_count && last_header)
 132                     img = last_header;
 133             }
 134         }
 135         if (!img) {
 136             NSObjectFileImage fileImage;
 137             int i, maxi;
 138             const char* prefixfilename;
 139             maxi = lib_path_count();
 140             for (i = 0; i < maxi && !img; i++) {
 141                 prefixfilename = lib_path_prefixify(i, filename);
 142                 callback_count = 0;
 143                 last_header = NULL;
 144                 if (NSCreateObjectFileImageFromFile(prefixfilename, &fileImage)
 145                     == NSObjectFileImageSuccess) {
 146                     NSLinkModule(fileImage, filename,
 147                                  NSLINKMODULE_OPTION_BINDNOW |
 148                                  ((flags & RTLD_GLOBAL)?NSLINKMODULE_OPTION_PRIVATE:0) |
 149                                  NSLINKMODULE_OPTION_RETURN_ON_ERROR);
 150                     if (callback_count && last_header)
 151                         img = last_header;
 152                 }
 153             }
 154         }
 155         if (img) {
 156             if (flags & RTLD_NOW) {
 157                 NSLookupSymbolInImage(img, "",
 158                                       NSLOOKUPSYMBOLINIMAGE_OPTION_BIND_FULLY |
 159                                       NSLOOKUPSYMBOLINIMAGE_OPTION_RETURN_ON_ERROR);
 160             }
 161             if (NSIsSymbolNameDefinedInImage(img, "__init")) {
 162                 NSSymbol* initsymbol;
 163                 void (*initfunc) (void);
 164                 initsymbol = NSLookupSymbolInImage(img, "__init", 0);
 165                 initfunc = NSAddressOfSymbol(initsymbol);
 166                 initfunc();
 167             }
 168         } else
 169             last_error = DLOPEN_ERROR;
 170         return img;
 171     }
 172 }
 173
 174 const char*
 175 dlerror()
 176 {
 177     NSLinkEditErrors c;
 178     int errorNumber;
 179     const char *fileName, *errorString;
 180     char *result = NULL;
 181
 182     if (last_error) {
 183         NSLinkEditError(&c, &errorNumber, &fileName, &errorString);
 184         /* The errorString obtained by the above is too verbose for
 185          * our needs, so we just translate the errno.
 186          *
 187          * We also have simple fallbacks in case we've somehow lost
 188          * the context before this point. */
 189         if (errorNumber) {
 190             result = strerror(errorNumber);
 191         } else if (DLSYM_ERROR == last_error) {
 192             result = "dlsym(3) failed";
 193         } else if (DLOPEN_ERROR == last_error) {
 194             result = "dlopen(3) failed";
 195         }
 196         last_error = 0;
 197     }
 198
 199     return result;
 200 }
 201
 202 void*
 203 dlsym(void* handle, char* symbol)
 204 {
 205     if (handle == &dl_self) {
 206         if (NSIsSymbolNameDefined(symbol)) {
 207             NSSymbol* retsym;
 208             retsym = NSLookupAndBindSymbol(symbol);
 209             return NSAddressOfSymbol(retsym);
 210         } else {
 211             last_error = DLSYM_ERROR;
 212             return NULL;
 213         }
 214     } else {
 215         if (NSIsSymbolNameDefinedInImage(handle, symbol)) {
 216             NSSymbol* retsym;
 217             retsym = NSLookupSymbolInImage(handle, symbol, 0);
 218             return NSAddressOfSymbol(retsym);
 219         } else {
 220             last_error = DLSYM_ERROR;
 221             return NULL;
 222         }
 223     }
 224 }
 225
 226 int
 227 dlclose(void *handle)
 228 {
 229     /* dlclose is not implemented, and never will be for dylibs.
 230      * return -1 to signal an error; it's not used by SBCL anyhow */
 231     return -1;
 232 }