The Tor Browser: security/nss/lib/util/secload.c@b8a032363ba2 (annotated)

security/nss/lib/util/secload.c@b8a032363ba2 (annotated)

security/nss/lib/util/secload.c

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* 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;
 }

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security/nss/lib/util/secload.c@b8a032363ba2 (annotated)

security/nss/lib/util/secload.c