/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#include "secport.h"
#include "nspr.h"
#ifdef XP_UNIX
#include <unistd.h>
#define BL_MAXSYMLINKS 20
/*
* If 'link' is a symbolic link, this function follows the symbolic links
* and returns the pathname of the ultimate source of the symbolic links.
* If 'link' is not a symbolic link, this function returns NULL.
* The caller should call PR_Free to free the string returned by this
* function.
*/
static char*
loader_GetOriginalPathname(
const char* link)
{
char* resolved = NULL;
char* input = NULL;
PRUint32 iterations = 0;
PRInt32 len = 0, retlen = 0;
if (!link) {
PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
return NULL;
}
len = PR_MAX(1024, strlen(link) + 1);
resolved = PR_Malloc(len);
input = PR_Malloc(len);
if (!resolved || !input) {
if (resolved) {
PR_Free(resolved);
}
if (input) {
PR_Free(input);
}
return NULL;
}
strcpy(input, link);
while ((iterations++ < BL_MAXSYMLINKS) &&
((retlen = readlink(input, resolved, len - 1)) > 0)) {
char* tmp = input;
resolved[retlen] =
'\0';
/* NULL termination */
input = resolved;
resolved = tmp;
}
PR_Free(resolved);
if (iterations == 1 && retlen < 0) {
PR_Free(input);
input = NULL;
}
return input;
}
#endif /* XP_UNIX */
/*
* Load the library with the file name 'name' residing in the same
* directory as the reference library, whose pathname is 'referencePath'.
*/
static PRLibrary*
loader_LoadLibInReferenceDir(
const char* referencePath,
const char* name)
{
PRLibrary* dlh = NULL;
char* fullName = NULL;
char* c;
PRLibSpec libSpec;
/* Remove the trailing filename from referencePath and add the new one */
c = strrchr(referencePath, PR_GetDirectorySeparator());
if (c) {
size_t referencePathSize = 1 + c - referencePath;
fullName = (
char*)PORT_Alloc(strlen(name) + referencePathSize + 1);
if (fullName) {
memcpy(fullName, referencePath, referencePathSize);
strcpy(fullName + referencePathSize, name);
#ifdef DEBUG_LOADER
PR_fprintf(PR_STDOUT,
"\nAttempting to load fully-qualified %s\n",
fullName);
#endif
libSpec.type = PR_LibSpec_Pathname;
libSpec.value.pathname = fullName;
dlh = PR_LoadLibraryWithFlags(libSpec, PR_LD_NOW | PR_LD_LOCAL
#ifdef PR_LD_ALT_SEARCH_PATH
/* allow library's dependencies to be found in the same directory
* on Windows even if PATH is not set. Requires NSPR 4.8.1 . */
| PR_LD_ALT_SEARCH_PATH
#endif
);
PORT_Free(fullName);
}
}
return dlh;
}
/*
* Load a shared library called "newShLibName" in the same directory as
* a shared library that is already loaded, called existingShLibName.
* A pointer to a static function in that shared library,
* staticShLibFunc, is required.
*
* existingShLibName:
* The file name of the shared library that shall be used as the
* "reference library". The loader will attempt to load the requested
* library from the same directory as the reference library.
*
* staticShLibFunc:
* Pointer to a static function in the "reference library".
*
* newShLibName:
* The simple file name of the new shared library to be loaded.
*
* We use PR_GetLibraryFilePathname to get the pathname of the loaded
* shared lib that contains this function, and then do a
* PR_LoadLibraryWithFlags with an absolute pathname for the shared
* library to be loaded.
*
* On Windows, the "alternate search path" strategy is employed, if available.
* On Unix, if existingShLibName is a symbolic link, and no link exists for the
* new library, the original link will be resolved, and the new library loaded
* from the resolved location.
*
* If the new shared library is not found in the same location as the reference
* library, it will then be loaded from the normal system library path.
*
*/
PRLibrary*
PORT_LoadLibraryFromOrigin(
const char* existingShLibName,
PRFuncPtr staticShLibFunc,
const char* newShLibName)
{
PRLibrary* lib = NULL;
char* fullPath = NULL;
PRLibSpec libSpec;
/* Get the pathname for existingShLibName, e.g. /usr/lib/libnss3.so
* PR_GetLibraryFilePathname works with either the base library name or a
* function pointer, depending on the platform.
* We require the address of a function in the "reference library",
* provided by the caller. To avoid getting the address of the stub/thunk
* of an exported function by accident, use the address of a static
* function rather than an exported function.
*/
fullPath = PR_GetLibraryFilePathname(existingShLibName,
staticShLibFunc);
if (fullPath) {
lib = loader_LoadLibInReferenceDir(fullPath, newShLibName);
#ifdef XP_UNIX
if (!lib) {
/*
* If fullPath is a symbolic link, resolve the symbolic
* link and try again.
*/
char* originalfullPath = loader_GetOriginalPathname(fullPath);
if (originalfullPath) {
PR_Free(fullPath);
fullPath = originalfullPath;
lib = loader_LoadLibInReferenceDir(fullPath, newShLibName);
}
}
#endif
PR_Free(fullPath);
}
if (!lib) {
#ifdef DEBUG_LOADER
PR_fprintf(PR_STDOUT,
"\nAttempting to load %s\n", newShLibName);
#endif
libSpec.type = PR_LibSpec_Pathname;
libSpec.value.pathname = newShLibName;
lib = PR_LoadLibraryWithFlags(libSpec, PR_LD_NOW | PR_LD_LOCAL);
}
if (NULL == lib) {
#ifdef DEBUG_LOADER
PR_fprintf(PR_STDOUT,
"\nLoading failed : %s.\n", newShLibName);
#endif
}
return lib;
}
