/PC/getpathp.c
http://unladen-swallow.googlecode.com/ · C · 714 lines · 495 code · 54 blank · 165 comment · 120 complexity · 224416e8d3fe2d668437aa82bf664775 MD5 · raw file
- /* 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 <windows.h>
- #include <tchar.h>
- #endif
- #ifdef HAVE_SYS_TYPES_H
- #include <sys/types.h>
- #endif /* HAVE_SYS_TYPES_H */
- #ifdef HAVE_SYS_STAT_H
- #include <sys/stat.h>
- #endif /* HAVE_SYS_STAT_H */
- #include <string.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 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<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);
- }
- /* return null if no path to return */
- if (dataSize == 0) goto done;
- /* original datasize from RegQueryInfo doesn't include the \0 */
- dataBuf = malloc((dataSize+1) * sizeof(TCHAR));
- if (dataBuf) {
- TCHAR *szCur = dataBuf;
- DWORD reqdSize = dataSize;
- /* Copy our collected strings */
- for (index=0;index<numKeys;index++) {
- if (index > 0) {
- *(szCur++) = _T(';');
- dataSize--;
- }
- if (ppPaths[index]) {
- Py_ssize_t len = _tcslen(ppPaths[index]);
- _tcsncpy(szCur, ppPaths[index], len);
- szCur += len;
- assert(dataSize > (DWORD)len);
- dataSize -= (DWORD)len;
- }
- }
- if (skipcore)
- *szCur = '\0';
- else {
- /* If we have no values, we dont need a ';' */
- if (numKeys) {
- *(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, reqdSize+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 /* Py_ENABLE_SHARED */
- #endif /* MS_WINDOWS */
- static void
- get_progpath(void)
- {
- extern char *Py_GetProgramName(void);
- char *path = getenv("PATH");
- char *prog = Py_GetProgramName();
- #ifdef MS_WINDOWS
- extern HANDLE PyWin_DLLhModule;
- #ifdef UNICODE
- WCHAR wprogpath[MAXPATHLEN+1];
- /* Windows documents that GetModuleFileName() will "truncate",
- but makes no mention of the null terminator. Play it safe.
- PLUS Windows itself defines MAX_PATH as the same, but anyway...
- */
- #ifdef Py_ENABLE_SHARED
- wprogpath[MAXPATHLEN]=_T('\0');
- if (PyWin_DLLhModule &&
- GetModuleFileName(PyWin_DLLhModule, wprogpath, MAXPATHLEN)) {
- WideCharToMultiByte(CP_ACP, 0,
- wprogpath, -1,
- dllpath, MAXPATHLEN+1,
- NULL, NULL);
- }
- #else
- dllpath[0] = 0;
- #endif
- wprogpath[MAXPATHLEN]=_T('\0');
- if (GetModuleFileName(NULL, wprogpath, MAXPATHLEN)) {
- WideCharToMultiByte(CP_ACP, 0,
- wprogpath, -1,
- progpath, MAXPATHLEN+1,
- NULL, NULL);
- return;
- }
- #else
- /* static init of progpath ensures final char remains \0 */
- #ifdef Py_ENABLE_SHARED
- if (PyWin_DLLhModule)
- if (!GetModuleFileName(PyWin_DLLhModule, dllpath, MAXPATHLEN))
- dllpath[0] = 0;
- #else
- dllpath[0] = 0;
- #endif
- 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
- strncpy(progpath, prog, MAXPATHLEN);
- else if (path) {
- while (1) {
- char *delim = strchr(path, DELIM);
- if (delim) {
- size_t len = delim - path;
- /* ensure we can't overwrite buffer */
- len = min(MAXPATHLEN,len);
- strncpy(progpath, path, len);
- *(progpath + len) = '\0';
- }
- else
- strncpy(progpath, path, MAXPATHLEN);
- /* join() is safe for MAXPATHLEN+1 size buffer */
- join(progpath, prog);
- if (exists(progpath))
- break;
- if (!delim) {
- progpath[0] = '\0';
- break;
- }
- path = delim + 1;
- }
- }
- else
- progpath[0] = '\0';
- }
- static void
- calculate_path(void)
- {
- char argv0_path[MAXPATHLEN+1];
- char *buf;
- size_t bufsz;
- char *pythonhome = Py_GetPythonHome();
- char *envpath = Py_GETENV("PYTHONPATH");
- #ifdef MS_WINDOWS
- int skiphome, skipdefault;
- char *machinepath = NULL;
- char *userpath = NULL;
- char zip_path[MAXPATHLEN+1];
- size_t len;
- #endif
- get_progpath();
- /* progpath guaranteed \0 terminated in MAXPATH+1 bytes. */
- 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
- strncpy(prefix, pythonhome, MAXPATHLEN);
- if (envpath && *envpath == '\0')
- envpath = NULL;
- #ifdef MS_WINDOWS
- /* Calculate zip archive path */
- if (dllpath[0]) /* use name of python DLL */
- strncpy(zip_path, dllpath, MAXPATHLEN);
- else /* use name of executable program */
- strncpy(zip_path, progpath, MAXPATHLEN);
- zip_path[MAXPATHLEN] = '\0';
- len = strlen(zip_path);
- if (len > 4) {
- zip_path[len-3] = 'z'; /* change ending to "zip" */
- zip_path[len-2] = 'i';
- zip_path[len-1] = 'p';
- }
- else {
- zip_path[0] = 0;
- }
-
- skiphome = pythonhome==NULL ? 0 : 1;
- #ifdef Py_ENABLE_SHARED
- machinepath = getpythonregpath(HKEY_LOCAL_MACHINE, skiphome);
- userpath = getpythonregpath(HKEY_CURRENT_USER, skiphome);
- #endif
- /* 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 zip archive file path;
- (3) for Win32, the machinepath and userpath, if set;
- (4) the PYTHONPATH config macro, with the leading "."
- of each component replaced with pythonhome, if set;
- (5) the directory containing the executable (argv0_path).
- The length calculation calculates #4 first.
- Extra rules:
- - If PYTHONHOME is set (in any way) item (3) is ignored.
- - If registry values are used, (4) and (5) 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_WINDOWS
- if (userpath)
- bufsz += strlen(userpath) + 1;
- if (machinepath)
- bufsz += strlen(machinepath) + 1;
- bufsz += strlen(zip_path) + 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_WINDOWS
- if (machinepath)
- free(machinepath);
- if (userpath)
- free(userpath);
- #endif /* MS_WINDOWS */
- return;
- }
- if (envpath) {
- strcpy(buf, envpath);
- buf = strchr(buf, '\0');
- *buf++ = DELIM;
- }
- #ifdef MS_WINDOWS
- if (zip_path[0]) {
- strcpy(buf, zip_path);
- buf = strchr(buf, '\0');
- *buf++ = DELIM;
- }
- 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_WINDOWS */
- else {
- char *p = PYTHONPATH;
- char *q;
- size_t 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';
- /* Now to pull one last hack/trick. If sys.prefix is
- empty, then try and find it somewhere on the paths
- we calculated. We scan backwards, as our general policy
- is that Python core directories are at the *end* of
- sys.path. We assume that our "lib" directory is
- on the path, and that our 'prefix' directory is
- the parent of that.
- */
- if (*prefix=='\0') {
- char lookBuf[MAXPATHLEN+1];
- char *look = buf - 1; /* 'buf' is at the end of the buffer */
- while (1) {
- Py_ssize_t nchars;
- char *lookEnd = look;
- /* 'look' will end up one character before the
- start of the path in question - even if this
- is one character before the start of the buffer
- */
- while (look >= 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;
- }