michael@0: /* This Source Code Form is subject to the terms of the Mozilla Public
michael@0:  * License, v. 2.0. If a copy of the MPL was not distributed with this
michael@0:  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
michael@0: 
michael@0: /*
michael@0:  * This file is meant to be included by other .c files.
michael@0:  * This file takes a "parameter", the scope which includes this
michael@0:  * code shall declare this variable:
michael@0:  *   const char *NameOfThisSharedLib;
michael@0:  *
michael@0:  * NameOfThisSharedLib:
michael@0:  *   The file name of the shared library that shall be used as the 
michael@0:  *   "reference library". The loader will attempt to load the requested
michael@0:  *   library from the same directory as the reference library.
michael@0:  */
michael@0: 
michael@0: #ifdef XP_UNIX
michael@0: #include <unistd.h>
michael@0: #define BL_MAXSYMLINKS 20
michael@0: 
michael@0: /*
michael@0:  * If 'link' is a symbolic link, this function follows the symbolic links
michael@0:  * and returns the pathname of the ultimate source of the symbolic links.
michael@0:  * If 'link' is not a symbolic link, this function returns NULL.
michael@0:  * The caller should call PR_Free to free the string returned by this
michael@0:  * function.
michael@0:  */
michael@0: static char* loader_GetOriginalPathname(const char* link)
michael@0: {
michael@0: #ifdef __GLIBC__
michael@0:     char* tmp = realpath(link, NULL);
michael@0:     char* resolved;
michael@0:     if (! tmp)
michael@0:     	return NULL;
michael@0:     resolved = PR_Malloc(strlen(tmp) + 1);
michael@0:     strcpy(resolved, tmp); /* This is necessary because PR_Free might not be using free() */
michael@0:     free(tmp);
michael@0:     return resolved;
michael@0: #else
michael@0:     char* resolved = NULL;
michael@0:     char* input = NULL;
michael@0:     PRUint32 iterations = 0;
michael@0:     PRInt32 len = 0, retlen = 0;
michael@0:     if (!link) {
michael@0:         PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
michael@0:         return NULL;
michael@0:     }
michael@0:     len = PR_MAX(1024, strlen(link) + 1);
michael@0:     resolved = PR_Malloc(len);
michael@0:     input = PR_Malloc(len);
michael@0:     if (!resolved || !input) {
michael@0:         if (resolved) {
michael@0:             PR_Free(resolved);
michael@0:         }
michael@0:         if (input) {
michael@0:             PR_Free(input);
michael@0:         }
michael@0:         return NULL;
michael@0:     }
michael@0:     strcpy(input, link);
michael@0:     while ( (iterations++ < BL_MAXSYMLINKS) &&
michael@0:             ( (retlen = readlink(input, resolved, len - 1)) > 0) ) {
michael@0:         char* tmp = input;
michael@0:         resolved[retlen] = '\0'; /* NULL termination */
michael@0:         input = resolved;
michael@0:         resolved = tmp;
michael@0:     }
michael@0:     PR_Free(resolved);
michael@0:     if (iterations == 1 && retlen < 0) {
michael@0:         PR_Free(input);
michael@0:         input = NULL;
michael@0:     }
michael@0:     return input;
michael@0: #endif
michael@0: }
michael@0: #endif /* XP_UNIX */
michael@0: 
michael@0: /*
michael@0:  * Load the library with the file name 'name' residing in the same
michael@0:  * directory as the reference library, whose pathname is 'referencePath'.
michael@0:  */
michael@0: static PRLibrary *
michael@0: loader_LoadLibInReferenceDir(const char *referencePath, const char *name)
michael@0: {
michael@0:     PRLibrary *dlh = NULL;
michael@0:     char *fullName = NULL;
michael@0:     char* c;
michael@0:     PRLibSpec libSpec;
michael@0: 
michael@0:     /* Remove the trailing filename from referencePath and add the new one */
michael@0:     c = strrchr(referencePath, PR_GetDirectorySeparator());
michael@0:     if (c) {
michael@0:         size_t referencePathSize = 1 + c - referencePath;
michael@0:         fullName = (char*) PORT_Alloc(strlen(name) + referencePathSize + 1);
michael@0:         if (fullName) {
michael@0:             memcpy(fullName, referencePath, referencePathSize);
michael@0:             strcpy(fullName + referencePathSize, name); 
michael@0: #ifdef DEBUG_LOADER
michael@0:             PR_fprintf(PR_STDOUT, "\nAttempting to load fully-qualified %s\n", 
michael@0:                        fullName);
michael@0: #endif
michael@0:             libSpec.type = PR_LibSpec_Pathname;
michael@0:             libSpec.value.pathname = fullName;
michael@0:             dlh = PR_LoadLibraryWithFlags(libSpec, PR_LD_NOW | PR_LD_LOCAL);
michael@0:             PORT_Free(fullName);
michael@0:         }
michael@0:     }
michael@0:     return dlh;
michael@0: }
michael@0: 
michael@0: /*
michael@0:  * We use PR_GetLibraryFilePathname to get the pathname of the loaded 
michael@0:  * shared lib that contains this function, and then do a PR_LoadLibrary
michael@0:  * with an absolute pathname for the softoken shared library.
michael@0:  */
michael@0: 
michael@0: static PRLibrary *
michael@0: loader_LoadLibrary(const char *nameToLoad)
michael@0: {
michael@0:     PRLibrary *lib = NULL;
michael@0:     char* fullPath = NULL;
michael@0:     PRLibSpec libSpec;
michael@0: 
michael@0:     /* Get the pathname for nameOfAlreadyLoadedLib, i.e. /usr/lib/libnss3.so
michael@0:      * PR_GetLibraryFilePathname works with either the base library name or a
michael@0:      * function pointer, depending on the platform. We can't query an exported
michael@0:      * symbol such as NSC_GetFunctionList, because on some platforms we can't
michael@0:      * find symbols in loaded implicit dependencies.
michael@0:      * But we can just get the address of this function !
michael@0:      */
michael@0:     fullPath = PR_GetLibraryFilePathname(NameOfThisSharedLib,
michael@0:                                          (PRFuncPtr)&loader_LoadLibrary);
michael@0: 
michael@0:     if (fullPath) {
michael@0:         lib = loader_LoadLibInReferenceDir(fullPath, nameToLoad);
michael@0: #ifdef XP_UNIX
michael@0:         if (!lib) {
michael@0:             /*
michael@0:              * If fullPath is a symbolic link, resolve the symbolic
michael@0:              * link and try again.
michael@0:              */
michael@0:             char* originalfullPath = loader_GetOriginalPathname(fullPath);
michael@0:             if (originalfullPath) {
michael@0:                 PR_Free(fullPath);
michael@0:                 fullPath = originalfullPath;
michael@0:                 lib = loader_LoadLibInReferenceDir(fullPath, nameToLoad);
michael@0:             }
michael@0:         }
michael@0: #endif
michael@0:         PR_Free(fullPath);
michael@0:     }
michael@0:     if (!lib) {
michael@0: #ifdef DEBUG_LOADER
michael@0:         PR_fprintf(PR_STDOUT, "\nAttempting to load %s\n", nameToLoad);
michael@0: #endif
michael@0:         libSpec.type = PR_LibSpec_Pathname;
michael@0:         libSpec.value.pathname = nameToLoad;
michael@0:         lib = PR_LoadLibraryWithFlags(libSpec, PR_LD_NOW | PR_LD_LOCAL);
michael@0:     }
michael@0:     if (NULL == lib) {
michael@0: #ifdef DEBUG_LOADER
michael@0:         PR_fprintf(PR_STDOUT, "\nLoading failed : %s.\n", nameToLoad);
michael@0: #endif
michael@0:     }
michael@0:     return lib;
michael@0: }
michael@0: