/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* 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 "primpl.h"

#include <string.h>

#ifdef XP_UNIX
#  ifdef USE_DLFCN
#    include <dlfcn.h>
/* Define these on systems that don't have them. */
#    ifndef RTLD_NOW
#      define RTLD_NOW 0
#    endif
#    ifndef RTLD_LAZY
#      define RTLD_LAZY RTLD_NOW
#    endif
#    ifndef RTLD_GLOBAL
#      define RTLD_GLOBAL 0
#    endif
#    ifndef RTLD_LOCAL
#      define RTLD_LOCAL 0
#    endif
#    ifdef AIX
#      include <sys/ldr.h>
#      ifndef L_IGNOREUNLOAD /* AIX 4.3.3 does not have L_IGNOREUNLOAD. */
#        define L_IGNOREUNLOAD 0x10000000
#      endif
#    endif
#  elif defined(USE_HPSHL)
#    include <dl.h>
#  endif
#endif /* XP_UNIX */

#define _PR_DEFAULT_LD_FLAGS PR_LD_LAZY

/*
 * On these platforms, symbols have a leading '_'.
 */
#if ((defined(OPENBSD) || defined(NETBSD)) && !defined(__ELF__))
#  define NEED_LEADING_UNDERSCORE
#endif

#define PR_LD_PATHW 0x8000 /* for PR_LibSpec_PathnameU */

/************************************************************************/

struct PRLibrary {
  char* name; /* Our own copy of the name string */
  PRLibrary* next;
  int refCount;
  const PRStaticLinkTable* staticTable;

#ifdef XP_PC
  HINSTANCE dlh;
#endif

#ifdef XP_UNIX
#  if defined(USE_HPSHL)
  shl_t dlh;
#  else
  void* dlh;
#  endif
#endif
};

static PRLibrary* pr_loadmap;
static PRLibrary* pr_exe_loadmap;
static PRMonitor* pr_linker_lock;
static char* _pr_currentLibPath = NULL;

static PRLibrary* pr_LoadLibraryByPathname(const char* name, PRIntn flags);

/************************************************************************/

#if !defined(USE_DLFCN) && !defined(HAVE_STRERROR)
#  define ERR_STR_BUF_LENGTH 20
#endif

static void DLLErrorInternal(PRIntn oserr)
/*
** This whole function, and most of the code in this file, are run
** with a big hairy lock wrapped around it. Not the best of situations,
** but will eventually come up with the right answer.
*/
{
  const char* error = NULL;
#ifdef USE_DLFCN
  error = dlerror(); /* $$$ That'll be wrong some of the time - AOF */
#elif defined(HAVE_STRERROR)
  error = strerror(oserr); /* this should be okay */
#else
  char errStrBuf[ERR_STR_BUF_LENGTH];
  PR_snprintf(errStrBuf, sizeof(errStrBuf), "error %d", oserr);
  error = errStrBuf;
#endif
  if (NULL != error) {
    PR_SetErrorText(strlen(error), error);
  }
} /* DLLErrorInternal */

void _PR_InitLinker(void) {
  PRLibrary* lm = NULL;
#if defined(XP_UNIX)
  void* h;
#endif

  if (!pr_linker_lock) {
    pr_linker_lock = PR_NewNamedMonitor("linker-lock");
  }
  PR_EnterMonitor(pr_linker_lock);

#if defined(XP_PC)
  lm = PR_NEWZAP(PRLibrary);
  lm->name = strdup("Executable");
  /* A module handle for the executable. */
  lm->dlh = GetModuleHandle(NULL);

  lm->refCount = 1;
  lm->staticTable = NULL;
  pr_exe_loadmap = lm;
  pr_loadmap = lm;

#elif defined(XP_UNIX)
#  ifdef HAVE_DLL
#    if defined(USE_DLFCN) && !defined(NO_DLOPEN_NULL)
  h = dlopen(0, RTLD_LAZY);
  if (!h) {
    char* error;

    DLLErrorInternal(_MD_ERRNO());
    error = (char*)PR_MALLOC(PR_GetErrorTextLength());
    (void)PR_GetErrorText(error);
    fprintf(stderr, "failed to initialize shared libraries [%s]\n", error);
    PR_DELETE(error);
    abort(); /* XXX */
  }
#    elif defined(USE_HPSHL)
  h = NULL;
  /* don't abort with this NULL */
#    elif defined(NO_DLOPEN_NULL)
  h = NULL; /* XXXX  toshok */ /* XXXX  vlad */
#    else
#      error no dll strategy
#    endif /* USE_DLFCN */

  lm = PR_NEWZAP(PRLibrary);
  if (lm) {
    lm->name = strdup("a.out");
    lm->refCount = 1;
    lm->dlh = h;
    lm->staticTable = NULL;
  }
  pr_exe_loadmap = lm;
  pr_loadmap = lm;
#  endif   /* HAVE_DLL */
#endif     /* XP_UNIX */

  if (lm) {
    PR_LOG(_pr_linker_lm, PR_LOG_MIN, ("Loaded library %s (init)", lm->name));
  }

  PR_ExitMonitor(pr_linker_lock);
}

/*
 * _PR_ShutdownLinker does not unload the dlls loaded by the application
 * via calls to PR_LoadLibrary.  Any dlls that still remain on the
 * pr_loadmap list when NSPR shuts down are application programming errors.
 * The only exception is pr_exe_loadmap, which was added to the list by
 * NSPR and hence should be cleaned up by NSPR.
 */
void _PR_ShutdownLinker(void) {
  /* FIXME: pr_exe_loadmap should be destroyed. */

  PR_DestroyMonitor(pr_linker_lock);
  pr_linker_lock = NULL;

  if (_pr_currentLibPath) {
    free(_pr_currentLibPath);
    _pr_currentLibPath = NULL;
  }
}

/******************************************************************************/

PR_IMPLEMENT(PRStatus) PR_SetLibraryPath(const char* path) {
  PRStatus rv = PR_SUCCESS;

  if (!_pr_initialized) {
    _PR_ImplicitInitialization();
  }
  PR_EnterMonitor(pr_linker_lock);
  if (_pr_currentLibPath) {
    free(_pr_currentLibPath);
  }
  if (path) {
    _pr_currentLibPath = strdup(path);
    if (!_pr_currentLibPath) {
      PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
      rv = PR_FAILURE;
    }
  } else {
    _pr_currentLibPath = 0;
  }
  PR_ExitMonitor(pr_linker_lock);
  return rv;
}

/*
** Return the library path for finding shared libraries.
*/
PR_IMPLEMENT(char*)
PR_GetLibraryPath(void) {
  char* ev;
  char* copy = NULL; /* a copy of _pr_currentLibPath */

  if (!_pr_initialized) {
    _PR_ImplicitInitialization();
  }
  PR_EnterMonitor(pr_linker_lock);
  if (_pr_currentLibPath != NULL) {
    goto exit;
  }

  /* initialize pr_currentLibPath */

#ifdef XP_PC
  ev = getenv("LD_LIBRARY_PATH");
  if (!ev) {
    ev = ".;\\lib";
  }
  ev = strdup(ev);
#endif

#if defined(XP_UNIX)
#  if defined(USE_DLFCN)
  {
    char* p = NULL;
    int len;

    ev = getenv("LD_LIBRARY_PATH");
    if (!ev) {
      ev = "/usr/lib:/lib";
    }
    len = strlen(ev) + 1; /* +1 for the null */

    p = (char*)malloc(len);
    if (p) {
      strcpy(p, ev);
    } /* if (p)  */
    ev = p;
    PR_LOG(_pr_io_lm, PR_LOG_NOTICE, ("linker path '%s'", ev));
  }
#  else
  /* AFAIK there isn't a library path with the HP SHL interface --Rob */
  ev = strdup("");
#  endif
#endif

  /*
   * If ev is NULL, we have run out of memory
   */
  _pr_currentLibPath = ev;

exit:
  if (_pr_currentLibPath) {
    copy = strdup(_pr_currentLibPath);
  }
  PR_ExitMonitor(pr_linker_lock);
  if (!copy) {
    PR_SetError(PR_OUT_OF_MEMORY_ERROR, 0);
  }
  return copy;
}

/*
** Build library name from path, lib and extensions
*/
PR_IMPLEMENT(char*)
PR_GetLibraryName(const char* path, const char* lib) {
  char* fullname;

#ifdef XP_PC
  if (strstr(lib, PR_DLL_SUFFIX) == NULL) {
    if (path) {
      fullname = PR_smprintf("%s\\%s%s", path, lib, PR_DLL_SUFFIX);
    } else {
      fullname = PR_smprintf("%s%s", lib, PR_DLL_SUFFIX);
    }
  } else {
    if (path) {
      fullname = PR_smprintf("%s\\%s", path, lib);
    } else {
      fullname = PR_smprintf("%s", lib);
    }
  }
#endif /* XP_PC */
#if defined(XP_UNIX)
  if (strstr(lib, PR_DLL_SUFFIX) == NULL) {
    if (path) {
      fullname = PR_smprintf("%s/lib%s%s", path, lib, PR_DLL_SUFFIX);
    } else {
      fullname = PR_smprintf("lib%s%s", lib, PR_DLL_SUFFIX);
    }
  } else {
    if (path) {
      fullname = PR_smprintf("%s/%s", path, lib);
    } else {
      fullname = PR_smprintf("%s", lib);
    }
  }
#endif /* XP_UNIX */
  return fullname;
}

/*
** Free the memory allocated, for the caller, by PR_GetLibraryName
*/
PR_IMPLEMENT(void)
PR_FreeLibraryName(char* mem) { PR_smprintf_free(mem); }

static PRLibrary* pr_UnlockedFindLibrary(const char* name) {
  PRLibrary* lm = pr_loadmap;
  const char* np = strrchr(name, PR_DIRECTORY_SEPARATOR);
  np = np ? np + 1 : name;
  while (lm) {
    const char* cp = strrchr(lm->name, PR_DIRECTORY_SEPARATOR);
    cp = cp ? cp + 1 : lm->name;
#ifdef WIN32
    /* Windows DLL names are case insensitive... */
    if (strcmpi(np, cp) == 0)
#else
    if (strcmp(np, cp) == 0)
#endif
    {
      /* found */
      lm->refCount++;
      PR_LOG(_pr_linker_lm, PR_LOG_MIN,
             ("%s incr => %d (find lib)", lm->name, lm->refCount));
      return lm;
    }
    lm = lm->next;
  }
  return NULL;
}

PR_IMPLEMENT(PRLibrary*)
PR_LoadLibraryWithFlags(PRLibSpec libSpec, PRIntn flags) {
  if (flags == 0) {
    flags = _PR_DEFAULT_LD_FLAGS;
  }
  switch (libSpec.type) {
    case PR_LibSpec_Pathname:
      return pr_LoadLibraryByPathname(libSpec.value.pathname, flags);
#ifdef WIN32
    case PR_LibSpec_PathnameU:
      /*
       * cast to |char *| and set PR_LD_PATHW flag so that
       * it can be cast back to PRUnichar* in the callee.
       */
      return pr_LoadLibraryByPathname((const char*)libSpec.value.pathname_u,
                                      flags | PR_LD_PATHW);
#endif
    default:
      PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
      return NULL;
  }
}

PR_IMPLEMENT(PRLibrary*)
PR_LoadLibrary(const char* name) {
  PRLibSpec libSpec;

  libSpec.type = PR_LibSpec_Pathname;
  libSpec.value.pathname = name;
  return PR_LoadLibraryWithFlags(libSpec, 0);
}

/*
** Dynamically load a library. Only load libraries once, so scan the load
** map first.
*/
static PRLibrary* pr_LoadLibraryByPathname(const char* name, PRIntn flags) {
  PRLibrary* lm;
  PRLibrary* result = NULL;
  PRInt32 oserr;
#ifdef WIN32
  char utf8name_stack[MAX_PATH];
  char* utf8name_malloc = NULL;
  char* utf8name = utf8name_stack;
  PRUnichar wname_stack[MAX_PATH];
  PRUnichar* wname_malloc = NULL;
  PRUnichar* wname = wname_stack;
  int len;
#endif

  if (!_pr_initialized) {
    _PR_ImplicitInitialization();
  }

  /* See if library is already loaded */
  PR_EnterMonitor(pr_linker_lock);

#ifdef WIN32
  if (flags & PR_LD_PATHW) {
    /* cast back what's cast to |char *| for the argument passing. */
    wname = (LPWSTR)name;
  } else {
    int wlen = MultiByteToWideChar(CP_ACP, 0, name, -1, NULL, 0);
    if (wlen > MAX_PATH) {
      wname = wname_malloc = PR_Malloc(wlen * sizeof(PRUnichar));
    }
    if (wname == NULL ||
        !MultiByteToWideChar(CP_ACP, 0, name, -1, wname, wlen)) {
      oserr = _MD_ERRNO();
      goto unlock;
    }
  }
  len = WideCharToMultiByte(CP_UTF8, 0, wname, -1, NULL, 0, NULL, NULL);
  if (len > MAX_PATH) {
    utf8name = utf8name_malloc = PR_Malloc(len);
  }
  if (utf8name == NULL ||
      !WideCharToMultiByte(CP_UTF8, 0, wname, -1, utf8name, len, NULL, NULL)) {
    oserr = _MD_ERRNO();
    goto unlock;
  }
  /* the list of loaded library names are always kept in UTF-8
   * on Win32 platforms */
  result = pr_UnlockedFindLibrary(utf8name);
#else
  result = pr_UnlockedFindLibrary(name);
#endif

  if (result != NULL) {
    goto unlock;
  }

  lm = PR_NEWZAP(PRLibrary);
  if (lm == NULL) {
    oserr = _MD_ERRNO();
    goto unlock;
  }
  lm->staticTable = NULL;

#ifdef WIN32
  {
    HINSTANCE h;

    h = LoadLibraryExW(
        wname, NULL,
        (flags & PR_LD_ALT_SEARCH_PATH) ? LOAD_WITH_ALTERED_SEARCH_PATH : 0);
    if (h == NULL) {
      oserr = _MD_ERRNO();
      PR_DELETE(lm);
      goto unlock;
    }
    lm->name = strdup(utf8name);
    lm->dlh = h;
    lm->next = pr_loadmap;
    pr_loadmap = lm;
  }
#endif /* WIN32 */

#if defined(XP_UNIX)
#  ifdef HAVE_DLL
  {
#    if defined(USE_DLFCN)
#      ifdef NTO
    /* Neutrino needs RTLD_GROUP to load Netscape plugins. (bug 71179) */
    int dl_flags = RTLD_GROUP;
#      elif defined(AIX)
    /* AIX needs RTLD_MEMBER to load an archive member.  (bug 228899) */
    int dl_flags = RTLD_MEMBER;
#      else
    int dl_flags = 0;
#      endif
    void* h = NULL;
#      if defined(DARWIN)
    PRBool okToLoad = PR_FALSE;
#      endif

    if (flags & PR_LD_LAZY) {
      dl_flags |= RTLD_LAZY;
    }
    if (flags & PR_LD_NOW) {
      dl_flags |= RTLD_NOW;
    }
    if (flags & PR_LD_GLOBAL) {
      dl_flags |= RTLD_GLOBAL;
    }
    if (flags & PR_LD_LOCAL) {
      dl_flags |= RTLD_LOCAL;
    }
#      if defined(DARWIN)
    /* If the file contains an absolute or relative path (slash)
     * and the path doesn't look like a System path, then require
     * the file exists.
     * The reason is that DARWIN's dlopen ignores the provided path
     * and checks for the plain filename in DYLD_LIBRARY_PATH,
     * which could load an unexpected version of a library. */
    if (strchr(name, PR_DIRECTORY_SEPARATOR) == NULL) {
      /* no slash, allow to load from any location */
      okToLoad = PR_TRUE;
    } else {
      const char systemPrefix1[] = "/System/";
      const size_t systemPrefixLen1 = strlen(systemPrefix1);
      const char systemPrefix2[] = "/usr/lib/";
      const size_t systemPrefixLen2 = strlen(systemPrefix2);
      const size_t name_len = strlen(name);
      if (((name_len > systemPrefixLen1) &&
           (strncmp(name, systemPrefix1, systemPrefixLen1) == 0)) ||
          ((name_len > systemPrefixLen2) &&
           (strncmp(name, systemPrefix2, systemPrefixLen2) == 0))) {
        /* found at beginning, it's a system library.
         * Skip filesystem check (required for macOS 11),
         * allow loading from any location */
        okToLoad = PR_TRUE;
      } else if (PR_Access(name, PR_ACCESS_EXISTS) == PR_SUCCESS) {
        /* file exists, allow to load */
        okToLoad = PR_TRUE;
      }
    }
    if (okToLoad) {
      h = dlopen(name, dl_flags);
    }
#      else
    h = dlopen(name, dl_flags);
#      endif
#    elif defined(USE_HPSHL)
    int shl_flags = 0;
    shl_t h;

    /*
     * Use the DYNAMIC_PATH flag only if 'name' is a plain file
     * name (containing no directory) to match the behavior of
     * dlopen().
     */
    if (strchr(name, PR_DIRECTORY_SEPARATOR) == NULL) {
      shl_flags |= DYNAMIC_PATH;
    }
    if (flags & PR_LD_LAZY) {
      shl_flags |= BIND_DEFERRED;
    }
    if (flags & PR_LD_NOW) {
      shl_flags |= BIND_IMMEDIATE;
    }
    /* No equivalent of PR_LD_GLOBAL and PR_LD_LOCAL. */
    h = shl_load(name, shl_flags, 0L);
#    else
#      error Configuration error
#    endif
    if (!h) {
      oserr = _MD_ERRNO();
      PR_DELETE(lm);
      goto unlock;
    }
    lm->name = strdup(name);
    lm->dlh = h;
    lm->next = pr_loadmap;
    pr_loadmap = lm;
  }
#  endif /* HAVE_DLL */
#endif   /* XP_UNIX */

  lm->refCount = 1;

  result = lm; /* success */
  PR_LOG(_pr_linker_lm, PR_LOG_MIN, ("Loaded library %s (load lib)", lm->name));

unlock:
  if (result == NULL) {
    PR_SetError(PR_LOAD_LIBRARY_ERROR, oserr);
    DLLErrorInternal(oserr); /* sets error text */
  }
#ifdef WIN32
  if (utf8name_malloc) {
    PR_Free(utf8name_malloc);
  }
  if (wname_malloc) {
    PR_Free(wname_malloc);
  }
#endif
  PR_ExitMonitor(pr_linker_lock);
  return result;
}

/*
** Unload a shared library which was loaded via PR_LoadLibrary
*/
PR_IMPLEMENT(PRStatus)
PR_UnloadLibrary(PRLibrary* lib) {
  int result = 0;
  PRStatus status = PR_SUCCESS;

  if (lib == 0) {
    PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
    return PR_FAILURE;
  }

  PR_EnterMonitor(pr_linker_lock);

  if (lib->refCount <= 0) {
    PR_ExitMonitor(pr_linker_lock);
    PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
    return PR_FAILURE;
  }

  if (--lib->refCount > 0) {
    PR_LOG(_pr_linker_lm, PR_LOG_MIN,
           ("%s decr => %d", lib->name, lib->refCount));
    goto done;
  }

#ifdef XP_UNIX
#  ifdef HAVE_DLL
#    ifdef USE_DLFCN
  result = dlclose(lib->dlh);
#    elif defined(USE_HPSHL)
  result = shl_unload(lib->dlh);
#    else
#      error Configuration error
#    endif
#  endif /* HAVE_DLL */
#endif   /* XP_UNIX */
#ifdef XP_PC
  if (lib->dlh) {
    FreeLibrary((HINSTANCE)(lib->dlh));
    lib->dlh = (HINSTANCE)NULL;
  }
#endif /* XP_PC */

  /* unlink from library search list */
  if (pr_loadmap == lib) {
    pr_loadmap = pr_loadmap->next;
  } else if (pr_loadmap != NULL) {
    PRLibrary* prev = pr_loadmap;
    PRLibrary* next = pr_loadmap->next;
    while (next != NULL) {
      if (next == lib) {
        prev->next = next->next;
        goto freeLib;
      }
      prev = next;
      next = next->next;
    }
    /*
     * fail (the library is not on the _pr_loadmap list),
     * but don't wipe out an error from dlclose/shl_unload.
     */
    PR_NOT_REACHED("_pr_loadmap and lib->refCount inconsistent");
    if (result == 0) {
      PR_SetError(PR_INVALID_ARGUMENT_ERROR, 0);
      status = PR_FAILURE;
    }
  }
  /*
   * We free the PRLibrary structure whether dlclose/shl_unload
   * succeeds or not.
   */

freeLib:
  PR_LOG(_pr_linker_lm, PR_LOG_MIN, ("Unloaded library %s", lib->name));
  free(lib->name);
  lib->name = NULL;
  PR_DELETE(lib);
  if (result != 0) {
    PR_SetError(PR_UNLOAD_LIBRARY_ERROR, _MD_ERRNO());
    DLLErrorInternal(_MD_ERRNO());
    status = PR_FAILURE;
  }

done:
  PR_ExitMonitor(pr_linker_lock);
  return status;
}

static void* pr_FindSymbolInLib(PRLibrary* lm, const char* name) {
  void* f = NULL;

  if (lm->staticTable != NULL) {
    const PRStaticLinkTable* tp;
    for (tp = lm->staticTable; tp->name; tp++) {
      if (strcmp(name, tp->name) == 0) {
        return (void*)tp->fp;
      }
    }
    /*
    ** If the symbol was not found in the static table then check if
    ** the symbol was exported in the DLL...
    */
    PR_SetError(PR_FIND_SYMBOL_ERROR, 0);
    return (void*)NULL;
  }

#ifdef WIN32
  f = GetProcAddress(lm->dlh, name);
#endif /* WIN32 */

#ifdef XP_UNIX
#  ifdef HAVE_DLL
#    ifdef USE_DLFCN
  f = dlsym(lm->dlh, name);
#    elif defined(USE_HPSHL)
  if (shl_findsym(&lm->dlh, name, TYPE_PROCEDURE, &f) == -1) {
    f = NULL;
  }
#    endif
#  endif /* HAVE_DLL */
#endif   /* XP_UNIX */
  if (f == NULL) {
    PR_SetError(PR_FIND_SYMBOL_ERROR, _MD_ERRNO());
    DLLErrorInternal(_MD_ERRNO());
  }
  return f;
}

/*
** Called by class loader to resolve missing native's
*/
PR_IMPLEMENT(void*)
PR_FindSymbol(PRLibrary* lib, const char* raw_name) {
  void* f = NULL;
#if defined(NEED_LEADING_UNDERSCORE)
  char* name;
#else
  const char* name;
#endif
  /*
  ** Mangle the raw symbol name in any way that is platform specific.
  */
#if defined(NEED_LEADING_UNDERSCORE)
  /* Need a leading _ */
  name = PR_smprintf("_%s", raw_name);
#elif defined(AIX)
  /*
  ** AIX with the normal linker put's a "." in front of the symbol
  ** name.  When use "svcc" and "svld" then the "." disappears. Go
  ** figure.
  */
  name = raw_name;
#else
  name = raw_name;
#endif

  PR_EnterMonitor(pr_linker_lock);
  PR_ASSERT(lib != NULL);
  f = pr_FindSymbolInLib(lib, name);

#if defined(NEED_LEADING_UNDERSCORE)
  PR_smprintf_free(name);
#endif

  PR_ExitMonitor(pr_linker_lock);
  return f;
}

/*
** Return the address of the function 'raw_name' in the library 'lib'
*/
PR_IMPLEMENT(PRFuncPtr)
PR_FindFunctionSymbol(PRLibrary* lib, const char* raw_name) {
  return ((PRFuncPtr)PR_FindSymbol(lib, raw_name));
}

PR_IMPLEMENT(void*)
PR_FindSymbolAndLibrary(const char* raw_name, PRLibrary** lib) {
  void* f = NULL;
#if defined(NEED_LEADING_UNDERSCORE)
  char* name;
#else
  const char* name;
#endif
  PRLibrary* lm;

  if (!_pr_initialized) {
    _PR_ImplicitInitialization();
  }
  /*
  ** Mangle the raw symbol name in any way that is platform specific.
  */
#if defined(NEED_LEADING_UNDERSCORE)
  /* Need a leading _ */
  name = PR_smprintf("_%s", raw_name);
#elif defined(AIX)
  /*
  ** AIX with the normal linker put's a "." in front of the symbol
  ** name.  When use "svcc" and "svld" then the "." disappears. Go
  ** figure.
  */
  name = raw_name;
#else
  name = raw_name;
#endif

  PR_EnterMonitor(pr_linker_lock);

  /* search all libraries */
  for (lm = pr_loadmap; lm != NULL; lm = lm->next) {
    f = pr_FindSymbolInLib(lm, name);
    if (f != NULL) {
      *lib = lm;
      lm->refCount++;
      PR_LOG(_pr_linker_lm, PR_LOG_MIN,
             ("%s incr => %d (for %s)", lm->name, lm->refCount, name));
      break;
    }
  }
#if defined(NEED_LEADING_UNDERSCORE)
  PR_smprintf_free(name);
#endif

  PR_ExitMonitor(pr_linker_lock);
  return f;
}

PR_IMPLEMENT(PRFuncPtr)
PR_FindFunctionSymbolAndLibrary(const char* raw_name, PRLibrary** lib) {
  return ((PRFuncPtr)PR_FindSymbolAndLibrary(raw_name, lib));
}

/*
** Add a static library to the list of loaded libraries. If LoadLibrary
** is called with the name then we will pretend it was already loaded
*/
PR_IMPLEMENT(PRLibrary*)
PR_LoadStaticLibrary(const char* name, const PRStaticLinkTable* slt) {
  PRLibrary* lm = NULL;
  PRLibrary* result = NULL;

  if (!_pr_initialized) {
    _PR_ImplicitInitialization();
  }

  /* See if library is already loaded */
  PR_EnterMonitor(pr_linker_lock);

  /* If the lbrary is already loaded, then add the static table information...
   */
  result = pr_UnlockedFindLibrary(name);
  if (result != NULL) {
    PR_ASSERT((result->staticTable == NULL) || (result->staticTable == slt));
    result->staticTable = slt;
    goto unlock;
  }

  /* Add library to list...Mark it static */
  lm = PR_NEWZAP(PRLibrary);
  if (lm == NULL) {
    goto unlock;
  }

  lm->name = strdup(name);
  lm->refCount = 1;
  lm->dlh = pr_exe_loadmap ? pr_exe_loadmap->dlh : 0;
  lm->staticTable = slt;
  lm->next = pr_loadmap;
  pr_loadmap = lm;

  result = lm; /* success */
  PR_ASSERT(lm->refCount == 1);
  PR_LOG(_pr_linker_lm, PR_LOG_MIN,
         ("Loaded library %s (static lib)", lm->name));
unlock:
  PR_ExitMonitor(pr_linker_lock);
  return result;
}

PR_IMPLEMENT(char*)
PR_GetLibraryFilePathname(const char* name, PRFuncPtr addr) {
#if defined(USE_DLFCN) && defined(HAVE_DLADDR)
  Dl_info dli;
  char* result;

  if (dladdr((void*)addr, &dli) == 0) {
    PR_SetError(PR_LIBRARY_NOT_LOADED_ERROR, _MD_ERRNO());
    DLLErrorInternal(_MD_ERRNO());
    return NULL;
  }
  result = PR_Malloc(strlen(dli.dli_fname) + 1);
  if (result != NULL) {
    strcpy(result, dli.dli_fname);
  }
  return result;
#elif defined(AIX)
  char* result;
#  define LD_INFO_INCREMENT 64
  struct ld_info* info;
  unsigned int info_length = LD_INFO_INCREMENT * sizeof(struct ld_info);
  struct ld_info* infop;
  int loadflags = L_GETINFO | L_IGNOREUNLOAD;

  for (;;) {
    info = PR_Malloc(info_length);
    if (info == NULL) {
      return NULL;
    }
    /* If buffer is too small, loadquery fails with ENOMEM. */
    if (loadquery(loadflags, info, info_length) != -1) {
      break;
    }
    /*
     * Calling loadquery when compiled for 64-bit with the
     * L_IGNOREUNLOAD flag can cause an invalid argument error
     * on AIX 5.1. Detect this error the first time that
     * loadquery is called, and try calling it again without
     * this flag set.
     */
    if (errno == EINVAL && (loadflags & L_IGNOREUNLOAD)) {
      loadflags &= ~L_IGNOREUNLOAD;
      if (loadquery(loadflags, info, info_length) != -1) {
        break;
      }
    }
    PR_Free(info);
    if (errno != ENOMEM) {
      /* should not happen */
      _PR_MD_MAP_DEFAULT_ERROR(_MD_ERRNO());
      return NULL;
    }
    /* retry with a larger buffer */
    info_length += LD_INFO_INCREMENT * sizeof(struct ld_info);
  }

  for (infop = info;;
       infop = (struct ld_info*)((char*)infop + infop->ldinfo_next)) {
    unsigned long start = (unsigned long)infop->ldinfo_dataorg;
    unsigned long end = start + infop->ldinfo_datasize;
    if (start <= (unsigned long)addr && end > (unsigned long)addr) {
      result = PR_Malloc(strlen(infop->ldinfo_filename) + 1);
      if (result != NULL) {
        strcpy(result, infop->ldinfo_filename);
      }
      break;
    }
    if (!infop->ldinfo_next) {
      PR_SetError(PR_LIBRARY_NOT_LOADED_ERROR, 0);
      result = NULL;
      break;
    }
  }
  PR_Free(info);
  return result;
#elif defined(HPUX) && defined(USE_HPSHL)
  int index;
  struct shl_descriptor desc;
  char* result;

  for (index = 0; shl_get_r(index, &desc) == 0; index++) {
    if (strstr(desc.filename, name) != NULL) {
      result = PR_Malloc(strlen(desc.filename) + 1);
      if (result != NULL) {
        strcpy(result, desc.filename);
      }
      return result;
    }
  }
  /*
   * Since the index value of a library is decremented if
   * a library preceding it in the shared library search
   * list was unloaded, it is possible that we missed some
   * libraries as we went up the list.  So we should go
   * down the list to be sure that we not miss anything.
   */
  for (index--; index >= 0; index--) {
    if ((shl_get_r(index, &desc) == 0) &&
        (strstr(desc.filename, name) != NULL)) {
      result = PR_Malloc(strlen(desc.filename) + 1);
      if (result != NULL) {
        strcpy(result, desc.filename);
      }
      return result;
    }
  }
  PR_SetError(PR_LIBRARY_NOT_LOADED_ERROR, 0);
  return NULL;
#elif defined(HPUX) && defined(USE_DLFCN)
  struct load_module_desc desc;
  char* result;
  const char* module_name;

  if (dlmodinfo((unsigned long)addr, &desc, sizeof desc, NULL, 0, 0) == 0) {
    PR_SetError(PR_LIBRARY_NOT_LOADED_ERROR, _MD_ERRNO());
    DLLErrorInternal(_MD_ERRNO());
    return NULL;
  }
  module_name = dlgetname(&desc, sizeof desc, NULL, 0, 0);
  if (module_name == NULL) {
    /* should not happen */
    _PR_MD_MAP_DEFAULT_ERROR(_MD_ERRNO());
    DLLErrorInternal(_MD_ERRNO());
    return NULL;
  }
  result = PR_Malloc(strlen(module_name) + 1);
  if (result != NULL) {
    strcpy(result, module_name);
  }
  return result;
#elif defined(WIN32)
  PRUnichar wname[MAX_PATH];
  HMODULE handle = NULL;
  PRUnichar module_name[MAX_PATH];
  int len;
  char* result;

  if (MultiByteToWideChar(CP_ACP, 0, name, -1, wname, MAX_PATH)) {
    handle = GetModuleHandleW(wname);
  }
  if (handle == NULL) {
    PR_SetError(PR_LIBRARY_NOT_LOADED_ERROR, _MD_ERRNO());
    DLLErrorInternal(_MD_ERRNO());
    return NULL;
  }
  if (GetModuleFileNameW(handle, module_name, MAX_PATH) == 0) {
    /* should not happen */
    _PR_MD_MAP_DEFAULT_ERROR(_MD_ERRNO());
    return NULL;
  }
  len = WideCharToMultiByte(CP_ACP, 0, module_name, -1, NULL, 0, NULL, NULL);
  if (len == 0) {
    _PR_MD_MAP_DEFAULT_ERROR(_MD_ERRNO());
    return NULL;
  }
  result = PR_Malloc(len * sizeof(PRUnichar));
  if (result != NULL) {
    WideCharToMultiByte(CP_ACP, 0, module_name, -1, result, len, NULL, NULL);
  }
  return result;
#else
  PR_SetError(PR_NOT_IMPLEMENTED_ERROR, 0);
  return NULL;
#endif
}
