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: #include "secport.h"
michael@0: #include "nspr.h"
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:     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: }
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: #ifdef PR_LD_ALT_SEARCH_PATH
michael@0:             /* allow library's dependencies to be found in the same directory
michael@0:              * on Windows even if PATH is not set. Requires NSPR 4.8.1 . */
michael@0:                                           | PR_LD_ALT_SEARCH_PATH 
michael@0: #endif
michael@0:                                           );
michael@0:             PORT_Free(fullName);
michael@0:         }
michael@0:     }
michael@0:     return dlh;
michael@0: }
michael@0: 
michael@0: /*
michael@0:  * Load a shared library called "newShLibName" in the same directory as
michael@0:  * a shared library that is already loaded, called existingShLibName.
michael@0:  * A pointer to a static function in that shared library,
michael@0:  * staticShLibFunc, is required.
michael@0:  *
michael@0:  * existingShLibName:
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:  * staticShLibFunc:
michael@0:  *   Pointer to a static function in the "reference library".
michael@0:  *
michael@0:  * newShLibName:
michael@0:  *   The simple file name of the new shared library to be loaded.
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
michael@0:  * PR_LoadLibraryWithFlags with an absolute pathname for the shared
michael@0:  * library to be loaded.
michael@0:  *
michael@0:  * On Windows, the "alternate search path" strategy is employed, if available.
michael@0:  * On Unix, if existingShLibName is a symbolic link, and no link exists for the
michael@0:  * new library, the original link will be resolved, and the new library loaded
michael@0:  * from the resolved location.
michael@0:  *
michael@0:  * If the new shared library is not found in the same location as the reference
michael@0:  * library, it will then be loaded from the normal system library path.
michael@0:  *
michael@0:  */
michael@0: 
michael@0: PRLibrary *
michael@0: PORT_LoadLibraryFromOrigin(const char* existingShLibName,
michael@0:                  PRFuncPtr staticShLibFunc,
michael@0:                  const char *newShLibName)
michael@0: {
michael@0:     PRLibrary *lib = NULL;
michael@0:     char* fullPath = NULL;
michael@0:     PRLibSpec libSpec;
michael@0: 
michael@0:     /* Get the pathname for existingShLibName, e.g. /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.
michael@0:      * We require the address of a function in the "reference library",
michael@0:      * provided by the caller. To avoid getting the address of the stub/thunk
michael@0:      * of an exported function by accident, use the address of a static
michael@0:      * function rather than an exported function.
michael@0:      */
michael@0:     fullPath = PR_GetLibraryFilePathname(existingShLibName,
michael@0:                                          staticShLibFunc);
michael@0: 
michael@0:     if (fullPath) {
michael@0:         lib = loader_LoadLibInReferenceDir(fullPath, newShLibName);
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, newShLibName);
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", newShLibName);
michael@0: #endif
michael@0:         libSpec.type = PR_LibSpec_Pathname;
michael@0:         libSpec.value.pathname = newShLibName;
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", newShLibName);
michael@0: #endif
michael@0:     }
michael@0:     return lib;
michael@0: }
michael@0: