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cpython/PC/getpathp.c

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/***********************************************************
Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
The Netherlands.
All Rights Reserved
Permission to use, copy, modify, and distribute this software and its
documentation for any purpose and without fee is hereby granted,
provided that the above copyright notice appear in all copies and that
both that copyright notice and this permission notice appear in
supporting documentation, and that the names of Stichting Mathematisch
Centrum or CWI or Corporation for National Research Initiatives or
CNRI not be used in advertising or publicity pertaining to
distribution of the software without specific, written prior
permission.
While CWI is the initial source for this software, a modified version
is made available by the Corporation for National Research Initiatives
(CNRI) at the Internet address ftp://ftp.python.org.
STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH
REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH
CENTRUM OR CNRI BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
PERFORMANCE OF THIS SOFTWARE.
******************************************************************/
/* 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, it's 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_WIN32
#include <windows.h>
#include <tchar.h>
#endif
#include <sys/types.h>
#include <sys/stat.h>
#include <string.h>
#if HAVE_UNISTD_H
#include <unistd.h>
#endif /* HAVE_UNISTD_H */
/* 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 *module_search_path = NULL;
static int
is_sep(ch) /* determine if "ch" is a separator character */
char ch;
{
#ifdef ALTSEP
return ch == SEP || ch == ALTSEP;
#else
return ch == SEP;
#endif
}
static void
reduce(dir)
char *dir;
{
int i = strlen(dir);
while (i > 0 && !is_sep(dir[i]))
--i;
dir[i] = '\0';
}
static int
exists(filename)
char *filename;
{
struct stat buf;
return stat(filename, &buf) == 0;
}
static int
ismodule(filename) /* Is module -- check for .pyc/.pyo too */
char *filename;
{
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;
}
static void
join(buffer, stuff)
char *buffer;
char *stuff;
{
int 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;
}
k = strlen(stuff);
if (n + k > MAXPATHLEN)
k = MAXPATHLEN - n;
strncpy(buffer+n, stuff, k);
buffer[n+k] = '\0';
}
static int
gotlandmark(landmark)
char *landmark;
{
int n, ok;
n = strlen(prefix);
join(prefix, landmark);
ok = ismodule(prefix);
prefix[n] = '\0';
return ok;
}
static int
search_for_prefix(argv0_path, landmark)
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_WIN32
/* 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.
*/
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");
int 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<numKeys;index++) {
TCHAR keyBuf[MAX_PATH+1];
HKEY subKey = 0;
DWORD reqdSize = MAX_PATH+1;
/* Get the sub-key name */
DWORD rc = RegEnumKeyEx(newKey, index, keyBuf, &reqdSize,
NULL, NULL, NULL, NULL );
if (rc!=ERROR_SUCCESS) goto done;
/* Open the sub-key */
rc=RegOpenKeyEx(newKey,
keyBuf, /* subkey */
0, /* reserved */
KEY_READ,
&subKey);
if (rc!=ERROR_SUCCESS) goto done;
/* Find the value of the buffer size, malloc, then read it */
RegQueryValueEx(subKey, NULL, 0, NULL, NULL, &reqdSize);
if (reqdSize) {
ppPaths[index] = malloc(reqdSize);
if (ppPaths[index]) {
RegQueryValueEx(subKey, NULL, 0, NULL, (LPBYTE)ppPaths[index], &reqdSize);
dataSize += reqdSize + 1; /* 1 for the ";" */
}
}
RegCloseKey(subKey);
}
dataBuf = malloc((dataSize+1) * sizeof(TCHAR));
if (dataBuf) {
TCHAR *szCur = dataBuf;
DWORD reqdSize = dataSize;
/* Copy our collected strings */
for (index=0;index<numKeys;index++) {
int len;
if (index > 0) {
*(szCur++) = _T(';');
dataSize--;
}
len = _tcslen(ppPaths[index]);
_tcsncpy(szCur, ppPaths[index], len);
szCur += len;
dataSize -= len;
}
if (skipcore)
*szCur = '\0';
else {
*(szCur++) = _T(';');
dataSize--;
/* Now append the core path entries - this will include the NULL */
rc = RegQueryValueEx(newKey, NULL, 0, NULL, (LPBYTE)szCur, &dataSize);
}
/* And set the result - caller must free
If MBCS, it is fine as is. If Unicode, allocate new
buffer and convert.
*/
#ifdef UNICODE
retval = (char *)malloc(reqdSize+1);
if (retval)
WideCharToMultiByte(CP_ACP, 0,
dataBuf, -1, /* source */
retval, dataSize+1, /* dest */
NULL, NULL);
free(dataBuf);
#else
retval = dataBuf;
#endif
}
done:
/* Loop freeing my temp buffers */
if (ppPaths) {
for(index=0;index<numKeys;index++)
if (ppPaths[index]) free(ppPaths[index]);
free(ppPaths);
}
if (newKey)
RegCloseKey(newKey);
if (keyBuf)
free(keyBuf);
return retval;
}
#endif /* MS_WIN32 */
static void
get_progpath()
{
extern char *Py_GetProgramName();
char *path = getenv("PATH");
char *prog = Py_GetProgramName();
#ifdef MS_WIN32
#ifdef UNICODE
WCHAR wprogpath[MAXPATHLEN+1];
if (GetModuleFileName(NULL, wprogpath, MAXPATHLEN)) {
WideCharToMultiByte(CP_ACP, 0, wprogpath, -1, progpath, MAXPATHLEN+1, NULL, NULL);
return;
}
#else
if (GetModuleFileName(NULL, progpath, MAXPATHLEN))
return;
#endif
#endif
if (prog == NULL || *prog == '\0')
prog = "python";
/* If there is no slash in the argv0 path, then we have to
* assume python is on the user's $PATH, since there's no
* other way to find a directory to start the search from. If
* $PATH isn't exported, you lose.
*/
#ifdef ALTSEP
if (strchr(prog, SEP) || strchr(prog, ALTSEP))
#else
if (strchr(prog, SEP))
#endif
strcpy(progpath, prog);
else if (path) {
while (1) {
char *delim = strchr(path, DELIM);
if (delim) {
int len = delim - path;
strncpy(progpath, path, len);
*(progpath + len) = '\0';
}
else
strcpy(progpath, path);
join(progpath, prog);
if (exists(progpath))
break;
if (!delim) {
progpath[0] = '\0';
break;
}
path = delim + 1;
}
}
else
progpath[0] = '\0';
}
static void
calculate_path()
{
char argv0_path[MAXPATHLEN+1];
char *buf;
int bufsz;
char *pythonhome = Py_GetPythonHome();
char *envpath = getenv("PYTHONPATH");
#ifdef MS_WIN32
int skiphome, skipdefault;
char *machinepath = NULL;
char *userpath = NULL;
#endif
get_progpath();
strcpy(argv0_path, progpath);
reduce(argv0_path);
if (pythonhome == NULL || *pythonhome == '\0') {
if (search_for_prefix(argv0_path, LANDMARK))
pythonhome = prefix;
else
pythonhome = NULL;
}
else
strcpy(prefix, pythonhome);
if (envpath && *envpath == '\0')
envpath = NULL;
#ifdef MS_WIN32
skiphome = pythonhome==NULL ? 0 : 1;
machinepath = getpythonregpath(HKEY_LOCAL_MACHINE, skiphome);
userpath = getpythonregpath(HKEY_CURRENT_USER, skiphome);
/* We only use the default relative PYTHONPATH if we havent
anything better to use! */
skipdefault = envpath!=NULL || pythonhome!=NULL || \
machinepath!=NULL || userpath!=NULL;
#endif
/* We need to construct a path from the following parts.
(1) the PYTHONPATH environment variable, if set;
(2) for Win32, the machinepath and userpath, if set;
(3) the PYTHONPATH config macro, with the leading "."
of each component replaced with pythonhome, if set;
(4) the directory containing the executable (argv0_path).
The length calculation calculates #3 first.
Extra rules:
- If PYTHONHOME is set (in any way) item (2) is ignored.
- If registry values are used, (3) and (4) are ignored.
*/
/* Calculate size of return buffer */
if (pythonhome != NULL) {
char *p;
bufsz = 1;
for (p = PYTHONPATH; *p; p++) {
if (*p == DELIM)
bufsz++; /* number of DELIM plus one */
}
bufsz *= strlen(pythonhome);
}
else
bufsz = 0;
bufsz += strlen(PYTHONPATH) + 1;
bufsz += strlen(argv0_path) + 1;
#ifdef MS_WIN32
if (userpath)
bufsz += strlen(userpath) + 1;
if (machinepath)
bufsz += strlen(machinepath) + 1;
#endif
if (envpath != NULL)
bufsz += strlen(envpath) + 1;
module_search_path = buf = malloc(bufsz);
if (buf == NULL) {
/* We can't exit, so print a warning and limp along */
fprintf(stderr, "Can't malloc dynamic PYTHONPATH.\n");
if (envpath) {
fprintf(stderr, "Using environment $PYTHONPATH.\n");
module_search_path = envpath;
}
else {
fprintf(stderr, "Using default static path.\n");
module_search_path = PYTHONPATH;
}
#ifdef MS_WIN32
if (machinepath)
free(machinepath);
if (userpath)
free(userpath);
#endif /* MS_WIN32 */
return;
}
if (envpath) {
strcpy(buf, envpath);
buf = strchr(buf, '\0');
*buf++ = DELIM;
}
#ifdef MS_WIN32
if (userpath) {
strcpy(buf, userpath);
buf = strchr(buf, '\0');
*buf++ = DELIM;
free(userpath);
}
if (machinepath) {
strcpy(buf, machinepath);
buf = strchr(buf, '\0');
*buf++ = DELIM;
free(machinepath);
}
if (pythonhome == NULL) {
if (!skipdefault) {
strcpy(buf, PYTHONPATH);
buf = strchr(buf, '\0');
}
}
#else
if (pythonhome == NULL) {
strcpy(buf, PYTHONPATH);
buf = strchr(buf, '\0');
}
#endif /* MS_WIN32 */
else {
char *p = PYTHONPATH;
char *q;
int n;
for (;;) {
q = strchr(p, DELIM);
if (q == NULL)
n = strlen(p);
else
n = q-p;
if (p[0] == '.' && is_sep(p[1])) {
strcpy(buf, pythonhome);
buf = strchr(buf, '\0');
p++;
n--;
}
strncpy(buf, p, n);
buf += n;
if (q == NULL)
break;
*buf++ = DELIM;
p = q+1;
}
}
if (argv0_path) {
*buf++ = DELIM;
strcpy(buf, argv0_path);
buf = strchr(buf, '\0');
}
*buf = '\0';
}
/* External interface */
char *
Py_GetPath()
{
if (!module_search_path)
calculate_path();
return module_search_path;
}
char *
Py_GetPrefix()
{
if (!module_search_path)
calculate_path();
return prefix;
}
char *
Py_GetExecPrefix()
{
return Py_GetPrefix();
}
char *
Py_GetProgramFullPath()
{
if (!module_search_path)
calculate_path();
return progpath;
}
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