/* Return the initial module search path. */
/* Used by DOS, OS/2, Windows 3.1, Windows 95/98, Windows NT. */
/* ----------------------------------------------------------------
PATH RULES FOR WINDOWS:
This describes how sys.path is formed on Windows. It describes the
functionality, not the implementation (ie, the order in which these
are actually fetched is different)
* Python always adds an empty entry at the start, which corresponds
to the current directory.
* If the PYTHONPATH env. var. exists, its entries are added next.
* We look in the registry for "application paths" - that is, sub-keys
under the main PythonPath registry key. These are added next (the
order of sub-key processing is undefined).
HKEY_CURRENT_USER is searched and added first.
HKEY_LOCAL_MACHINE is searched and added next.
(Note that all known installers only use HKLM, so HKCU is typically
empty)
* We attempt to locate the "Python Home" - if the PYTHONHOME env var
is set, we believe it. Otherwise, we use the path of our host .EXE's
to try and locate our "landmark" (lib\\os.py) and deduce our home.
- If we DO have a Python Home: The relevant sub-directories (Lib,
plat-win, lib-tk, etc) are based on the Python Home
- If we DO NOT have a Python Home, the core Python Path is
loaded from the registry. This is the main PythonPath key,
and both HKLM and HKCU are combined to form the path)
* Iff - we can not locate the Python Home, have not had a PYTHONPATH
specified, and can't locate any Registry entries (ie, we have _nothing_
we can assume is a good path), a default path with relative entries is
used (eg. .\Lib;.\plat-win, etc)
The end result of all this is:
* When running python.exe, or any other .exe in the main Python directory
(either an installed version, or directly from the PCbuild directory),
the core path is deduced, and the core paths in the registry are
ignored. Other "application paths" in the registry are always read.
* When Python is hosted in another exe (different directory, embedded via
COM, etc), the Python Home will not be deduced, so the core path from
the registry is used. Other "application paths" in the registry are
always read.
* If Python can't find its home and there is no registry (eg, frozen
exe, some very strange installation setup) you get a path with
some default, but relative, paths.
---------------------------------------------------------------- */
#include "Python.h"
#include "osdefs.h"
#ifdef MS_WINDOWS
#include
#include
#endif
#ifdef HAVE_SYS_TYPES_H
#include
#endif /* HAVE_SYS_TYPES_H */
#ifdef HAVE_SYS_STAT_H
#include
#endif /* HAVE_SYS_STAT_H */
#include
/* Search in some common locations for the associated Python libraries.
*
* Py_GetPath() tries to return a sensible Python module search path.
*
* The approach is an adaptation for Windows of the strategy used in
* ../Modules/getpath.c; it uses the Windows Registry as one of its
* information sources.
*/
#ifndef LANDMARK
#define LANDMARK "lib\\os.py"
#endif
static char prefix[MAXPATHLEN+1];
static char progpath[MAXPATHLEN+1];
static char dllpath[MAXPATHLEN+1];
static char *module_search_path = NULL;
static int
is_sep(char ch) /* determine if "ch" is a separator character */
{
#ifdef ALTSEP
return ch == SEP || ch == ALTSEP;
#else
return ch == SEP;
#endif
}
/* assumes 'dir' null terminated in bounds. Never writes
beyond existing terminator.
*/
static void
reduce(char *dir)
{
size_t i = strlen(dir);
while (i > 0 && !is_sep(dir[i]))
--i;
dir[i] = '\0';
}
static int
exists(char *filename)
{
struct stat buf;
return stat(filename, &buf) == 0;
}
/* Assumes 'filename' MAXPATHLEN+1 bytes long -
may extend 'filename' by one character.
*/
static int
ismodule(char *filename) /* Is module -- check for .pyc/.pyo too */
{
if (exists(filename))
return 1;
/* Check for the compiled version of prefix. */
if (strlen(filename) < MAXPATHLEN) {
strcat(filename, Py_OptimizeFlag ? "o" : "c");
if (exists(filename))
return 1;
}
return 0;
}
/* Add a path component, by appending stuff to buffer.
buffer must have at least MAXPATHLEN + 1 bytes allocated, and contain a
NUL-terminated string with no more than MAXPATHLEN characters (not counting
the trailing NUL). It's a fatal error if it contains a string longer than
that (callers must be careful!). If these requirements are met, it's
guaranteed that buffer will still be a NUL-terminated string with no more
than MAXPATHLEN characters at exit. If stuff is too long, only as much of
stuff as fits will be appended.
*/
static void
join(char *buffer, char *stuff)
{
size_t n, k;
if (is_sep(stuff[0]))
n = 0;
else {
n = strlen(buffer);
if (n > 0 && !is_sep(buffer[n-1]) && n < MAXPATHLEN)
buffer[n++] = SEP;
}
if (n > MAXPATHLEN)
Py_FatalError("buffer overflow in getpathp.c's joinpath()");
k = strlen(stuff);
if (n + k > MAXPATHLEN)
k = MAXPATHLEN - n;
strncpy(buffer+n, stuff, k);
buffer[n+k] = '\0';
}
/* gotlandmark only called by search_for_prefix, which ensures
'prefix' is null terminated in bounds. join() ensures
'landmark' can not overflow prefix if too long.
*/
static int
gotlandmark(char *landmark)
{
int ok;
Py_ssize_t n;
n = strlen(prefix);
join(prefix, landmark);
ok = ismodule(prefix);
prefix[n] = '\0';
return ok;
}
/* assumes argv0_path is MAXPATHLEN+1 bytes long, already \0 term'd.
assumption provided by only caller, calculate_path() */
static int
search_for_prefix(char *argv0_path, char *landmark)
{
/* Search from argv0_path, until landmark is found */
strcpy(prefix, argv0_path);
do {
if (gotlandmark(landmark))
return 1;
reduce(prefix);
} while (prefix[0]);
return 0;
}
#ifdef MS_WINDOWS
#ifdef Py_ENABLE_SHARED
/* a string loaded from the DLL at startup.*/
extern const char *PyWin_DLLVersionString;
/* Load a PYTHONPATH value from the registry.
Load from either HKEY_LOCAL_MACHINE or HKEY_CURRENT_USER.
Works in both Unicode and 8bit environments. Only uses the
Ex family of functions so it also works with Windows CE.
Returns NULL, or a pointer that should be freed.
XXX - this code is pretty strange, as it used to also
work on Win16, where the buffer sizes werent available
in advance. It could be simplied now Win16/Win32s is dead!
*/
static char *
getpythonregpath(HKEY keyBase, int skipcore)
{
HKEY newKey = 0;
DWORD dataSize = 0;
DWORD numKeys = 0;
LONG rc;
char *retval = NULL;
TCHAR *dataBuf = NULL;
static const TCHAR keyPrefix[] = _T("Software\\Python\\PythonCore\\");
static const TCHAR keySuffix[] = _T("\\PythonPath");
size_t versionLen;
DWORD index;
TCHAR *keyBuf = NULL;
TCHAR *keyBufPtr;
TCHAR **ppPaths = NULL;
/* Tried to use sysget("winver") but here is too early :-( */
versionLen = _tcslen(PyWin_DLLVersionString);
/* Space for all the chars, plus one \0 */
keyBuf = keyBufPtr = malloc(sizeof(keyPrefix) +
sizeof(TCHAR)*(versionLen-1) +
sizeof(keySuffix));
if (keyBuf==NULL) goto done;
memcpy(keyBufPtr, keyPrefix, sizeof(keyPrefix)-sizeof(TCHAR));
keyBufPtr += sizeof(keyPrefix)/sizeof(TCHAR) - 1;
memcpy(keyBufPtr, PyWin_DLLVersionString, versionLen * sizeof(TCHAR));
keyBufPtr += versionLen;
/* NULL comes with this one! */
memcpy(keyBufPtr, keySuffix, sizeof(keySuffix));
/* Open the root Python key */
rc=RegOpenKeyEx(keyBase,
keyBuf, /* subkey */
0, /* reserved */
KEY_READ,
&newKey);
if (rc!=ERROR_SUCCESS) goto done;
/* Find out how big our core buffer is, and how many subkeys we have */
rc = RegQueryInfoKey(newKey, NULL, NULL, NULL, &numKeys, NULL, NULL,
NULL, NULL, &dataSize, NULL, NULL);
if (rc!=ERROR_SUCCESS) goto done;
if (skipcore) dataSize = 0; /* Only count core ones if we want them! */
/* Allocate a temp array of char buffers, so we only need to loop
reading the registry once
*/
ppPaths = malloc( sizeof(TCHAR *) * numKeys );
if (ppPaths==NULL) goto done;
memset(ppPaths, 0, sizeof(TCHAR *) * numKeys);
/* Loop over all subkeys, allocating a temp sub-buffer. */
for(index=0;index= module_search_path && *look != DELIM)
look--;
nchars = lookEnd-look;
strncpy(lookBuf, look+1, nchars);
lookBuf[nchars] = '\0';
/* Up one level to the parent */
reduce(lookBuf);
if (search_for_prefix(lookBuf, LANDMARK)) {
break;
}
/* If we are out of paths to search - give up */
if (look < module_search_path)
break;
look--;
}
}
}
/* External interface */
char *
Py_GetPath(void)
{
if (!module_search_path)
calculate_path();
return module_search_path;
}
char *
Py_GetPrefix(void)
{
if (!module_search_path)
calculate_path();
return prefix;
}
char *
Py_GetExecPrefix(void)
{
return Py_GetPrefix();
}
char *
Py_GetProgramFullPath(void)
{
if (!module_search_path)
calculate_path();
return progpath;
}