1 /* Return the initial module search path. */
10 #include <mach-o/dyld.h>
13 /* Search in some common locations for the associated Python libraries.
15 * Two directories must be found, the platform independent directory
16 * (prefix), containing the common .py and .pyc files, and the platform
17 * dependent directory (exec_prefix), containing the shared library
18 * modules. Note that prefix and exec_prefix can be the same directory,
19 * but for some installations, they are different.
21 * Py_GetPath() carries out separate searches for prefix and exec_prefix.
22 * Each search tries a number of different locations until a ``landmark''
23 * file or directory is found. If no prefix or exec_prefix is found, a
24 * warning message is issued and the preprocessor defined PREFIX and
25 * EXEC_PREFIX are used (even though they will not work); python carries on
26 * as best as is possible, but most imports will fail.
28 * Before any searches are done, the location of the executable is
29 * determined. If argv[0] has one or more slashs in it, it is used
30 * unchanged. Otherwise, it must have been invoked from the shell's path,
31 * so we search $PATH for the named executable and use that. If the
32 * executable was not found on $PATH (or there was no $PATH environment
33 * variable), the original argv[0] string is used.
35 * Next, the executable location is examined to see if it is a symbolic
36 * link. If so, the link is chased (correctly interpreting a relative
37 * pathname if one is found) and the directory of the link target is used.
39 * Finally, argv0_path is set to the directory containing the executable
40 * (i.e. the last component is stripped).
42 * With argv0_path in hand, we perform a number of steps. The same steps
43 * are performed for prefix and for exec_prefix, but with a different
46 * Step 1. Are we running python out of the build directory? This is
47 * checked by looking for a different kind of landmark relative to
48 * argv0_path. For prefix, the landmark's path is derived from the VPATH
49 * preprocessor variable (taking into account that its value is almost, but
50 * not quite, what we need). For exec_prefix, the landmark is
51 * Modules/Setup. If the landmark is found, we're done.
53 * For the remaining steps, the prefix landmark will always be
54 * lib/python$VERSION/os.py and the exec_prefix will always be
55 * lib/python$VERSION/lib-dynload, where $VERSION is Python's version
56 * number as supplied by the Makefile. Note that this means that no more
57 * build directory checking is performed; if the first step did not find
58 * the landmarks, the assumption is that python is running from an
61 * Step 2. See if the $PYTHONHOME environment variable points to the
62 * installed location of the Python libraries. If $PYTHONHOME is set, then
63 * it points to prefix and exec_prefix. $PYTHONHOME can be a single
64 * directory, which is used for both, or the prefix and exec_prefix
65 * directories separated by a colon.
67 * Step 3. Try to find prefix and exec_prefix relative to argv0_path,
68 * backtracking up the path until it is exhausted. This is the most common
69 * step to succeed. Note that if prefix and exec_prefix are different,
70 * exec_prefix is more likely to be found; however if exec_prefix is a
71 * subdirectory of prefix, both will be found.
73 * Step 4. Search the directories pointed to by the preprocessor variables
74 * PREFIX and EXEC_PREFIX. These are supplied by the Makefile but can be
75 * passed in as options to the configure script.
79 * Well, almost. Once we have determined prefix and exec_prefix, the
80 * preprocessor variable PYTHONPATH is used to construct a path. Each
81 * relative path on PYTHONPATH is prefixed with prefix. Then the directory
82 * containing the shared library modules is appended. The environment
83 * variable $PYTHONPATH is inserted in front of it all. Finally, the
84 * prefix and exec_prefix globals are tweaked so they reflect the values
85 * expected by other code, by stripping the "lib/python$VERSION/..." stuff
86 * off. If either points to the build directory, the globals are reset to
87 * the corresponding preprocessor variables (so sys.prefix will reflect the
88 * installation location, even though sys.path points into the build
89 * directory). This seems to make more sense given that currently the only
90 * known use of sys.prefix and sys.exec_prefix is for the ILU installation
91 * process to find the installed Python tree.
101 #define VERSION "2_1"
103 #define VERSION "2.1"
112 #define PREFIX "/usr/local"
116 #define EXEC_PREFIX PREFIX
120 #define PYTHONPATH PREFIX "/lib/python" VERSION ":" \
121 EXEC_PREFIX "/lib/python" VERSION "/lib-dynload"
125 #define LANDMARK "os.py"
128 static char prefix
[MAXPATHLEN
+1];
129 static char exec_prefix
[MAXPATHLEN
+1];
130 static char progpath
[MAXPATHLEN
+1];
131 static char *module_search_path
= NULL
;
132 static char lib_python
[] = "lib/python" VERSION
;
137 size_t i
= strlen(dir
);
138 while (i
> 0 && dir
[i
] != SEP
)
145 isfile(char *filename
) /* Is file, not directory */
148 if (stat(filename
, &buf
) != 0)
150 if (!S_ISREG(buf
.st_mode
))
157 ismodule(char *filename
) /* Is module -- check for .pyc/.pyo too */
159 if (isfile(filename
))
162 /* Check for the compiled version of prefix. */
163 if (strlen(filename
) < MAXPATHLEN
) {
164 strcat(filename
, Py_OptimizeFlag
? "o" : "c");
165 if (isfile(filename
))
173 isxfile(char *filename
) /* Is executable file */
176 if (stat(filename
, &buf
) != 0)
178 if (!S_ISREG(buf
.st_mode
))
180 if ((buf
.st_mode
& 0111) == 0)
187 isdir(char *filename
) /* Is directory */
190 if (stat(filename
, &buf
) != 0)
192 if (!S_ISDIR(buf
.st_mode
))
198 /* Add a path component, by appending stuff to buffer.
199 buffer must have at least MAXPATHLEN + 1 bytes allocated, and contain a
200 NUL-terminated string with no more than MAXPATHLEN characters (not counting
201 the trailing NUL). It's a fatal error if it contains a string longer than
202 that (callers must be careful!). If these requirements are met, it's
203 guaranteed that buffer will still be a NUL-terminated string with no more
204 than MAXPATHLEN characters at exit. If stuff is too long, only as much of
205 stuff as fits will be appended.
208 joinpath(char *buffer
, char *stuff
)
215 if (n
> 0 && buffer
[n
-1] != SEP
&& n
< MAXPATHLEN
)
219 Py_FatalError("buffer overflow in getpath.c's joinpath()");
221 if (n
+ k
> MAXPATHLEN
)
223 strncpy(buffer
+n
, stuff
, k
);
227 /* copy_absolute requires that path be allocated at least
228 MAXPATHLEN + 1 bytes and that p be no more than MAXPATHLEN bytes. */
230 copy_absolute(char *path
, char *p
)
235 getcwd(path
, MAXPATHLEN
);
236 if (p
[0] == '.' && p
[1] == SEP
)
242 /* absolutize() requires that path be allocated at least MAXPATHLEN+1 bytes. */
244 absolutize(char *path
)
246 char buffer
[MAXPATHLEN
+ 1];
250 copy_absolute(buffer
, path
);
251 strcpy(path
, buffer
);
254 /* search_for_prefix requires that argv0_path be no more than MAXPATHLEN
258 search_for_prefix(char *argv0_path
, char *home
)
263 /* If PYTHONHOME is set, we believe it unconditionally */
266 strncpy(prefix
, home
, MAXPATHLEN
);
267 delim
= strchr(prefix
, DELIM
);
270 joinpath(prefix
, lib_python
);
271 joinpath(prefix
, LANDMARK
);
275 /* Check to see if argv[0] is in the build directory */
276 strcpy(prefix
, argv0_path
);
277 joinpath(prefix
, "Modules/Setup");
278 if (isfile(prefix
)) {
279 /* Check VPATH to see if argv0_path is in the build directory. */
281 strcpy(prefix
, argv0_path
);
282 joinpath(prefix
, vpath
);
283 joinpath(prefix
, "Lib");
284 joinpath(prefix
, LANDMARK
);
285 if (ismodule(prefix
))
289 /* Search from argv0_path, until root is found */
290 copy_absolute(prefix
, argv0_path
);
293 joinpath(prefix
, lib_python
);
294 joinpath(prefix
, LANDMARK
);
295 if (ismodule(prefix
))
301 /* Look at configure's PREFIX */
302 strncpy(prefix
, PREFIX
, MAXPATHLEN
);
303 joinpath(prefix
, lib_python
);
304 joinpath(prefix
, LANDMARK
);
305 if (ismodule(prefix
))
313 /* search_for_exec_prefix requires that argv0_path be no more than
314 MAXPATHLEN bytes long.
317 search_for_exec_prefix(char *argv0_path
, char *home
)
321 /* If PYTHONHOME is set, we believe it unconditionally */
324 delim
= strchr(home
, DELIM
);
326 strncpy(exec_prefix
, delim
+1, MAXPATHLEN
);
328 strncpy(exec_prefix
, home
, MAXPATHLEN
);
329 joinpath(exec_prefix
, lib_python
);
330 joinpath(exec_prefix
, "lib-dynload");
334 /* Check to see if argv[0] is in the build directory */
335 strcpy(exec_prefix
, argv0_path
);
336 joinpath(exec_prefix
, "Modules/Setup");
337 if (isfile(exec_prefix
)) {
342 /* Search from argv0_path, until root is found */
343 copy_absolute(exec_prefix
, argv0_path
);
345 n
= strlen(exec_prefix
);
346 joinpath(exec_prefix
, lib_python
);
347 joinpath(exec_prefix
, "lib-dynload");
348 if (isdir(exec_prefix
))
350 exec_prefix
[n
] = '\0';
352 } while (exec_prefix
[0]);
354 /* Look at configure's EXEC_PREFIX */
355 strncpy(exec_prefix
, EXEC_PREFIX
, MAXPATHLEN
);
356 joinpath(exec_prefix
, lib_python
);
357 joinpath(exec_prefix
, "lib-dynload");
358 if (isdir(exec_prefix
))
369 extern char *Py_GetProgramName(void);
371 static char delimiter
[2] = {DELIM
, '\0'};
372 static char separator
[2] = {SEP
, '\0'};
373 char *pythonpath
= PYTHONPATH
;
374 char *rtpypath
= Py_GETENV("PYTHONPATH");
375 char *home
= Py_GetPythonHome();
376 char *path
= getenv("PATH");
377 char *prog
= Py_GetProgramName();
378 char argv0_path
[MAXPATHLEN
+1];
379 char zip_path
[MAXPATHLEN
+1];
380 int pfound
, efound
; /* 1 if found; -1 if found build directory */
384 char *defpath
= pythonpath
;
385 #ifdef WITH_NEXT_FRAMEWORK
386 NSModule pythonModule
;
389 #if MAC_OS_X_VERSION_MAX_ALLOWED >= MAC_OS_X_VERSION_10_4
390 uint32_t nsexeclength
= MAXPATHLEN
;
392 unsigned long nsexeclength
= MAXPATHLEN
;
396 /* If there is no slash in the argv0 path, then we have to
397 * assume python is on the user's $PATH, since there's no
398 * other way to find a directory to start the search from. If
399 * $PATH isn't exported, you lose.
401 if (strchr(prog
, SEP
))
402 strncpy(progpath
, prog
, MAXPATHLEN
);
404 /* On Mac OS X, if a script uses an interpreter of the form
405 * "#!/opt/python2.3/bin/python", the kernel only passes "python"
406 * as argv[0], which falls through to the $PATH search below.
407 * If /opt/python2.3/bin isn't in your path, or is near the end,
408 * this algorithm may incorrectly find /usr/bin/python. To work
409 * around this, we can use _NSGetExecutablePath to get a better
410 * hint of what the intended interpreter was, although this
411 * will fail if a relative path was used. but in that case,
412 * absolutize() should help us out below
414 else if(0 == _NSGetExecutablePath(progpath
, &nsexeclength
) && progpath
[0] == SEP
)
416 #endif /* __APPLE__ */
419 char *delim
= strchr(path
, DELIM
);
422 size_t len
= delim
- path
;
423 if (len
> MAXPATHLEN
)
425 strncpy(progpath
, path
, len
);
426 *(progpath
+ len
) = '\0';
429 strncpy(progpath
, path
, MAXPATHLEN
);
431 joinpath(progpath
, prog
);
432 if (isxfile(progpath
))
444 if (progpath
[0] != SEP
)
445 absolutize(progpath
);
446 strncpy(argv0_path
, progpath
, MAXPATHLEN
);
447 argv0_path
[MAXPATHLEN
] = '\0';
449 #ifdef WITH_NEXT_FRAMEWORK
450 /* On Mac OS X we have a special case if we're running from a framework.
451 ** This is because the python home should be set relative to the library,
452 ** which is in the framework, not relative to the executable, which may
453 ** be outside of the framework. Except when we're in the build directory...
455 pythonModule
= NSModuleForSymbol(NSLookupAndBindSymbol("_Py_Initialize"));
456 /* Use dylib functions to find out where the framework was loaded from */
457 buf
= (char *)NSLibraryNameForModule(pythonModule
);
459 /* We're in a framework. */
460 /* See if we might be in the build directory. The framework in the
461 ** build directory is incomplete, it only has the .dylib and a few
462 ** needed symlinks, it doesn't have the Lib directories and such.
463 ** If we're running with the framework from the build directory we must
464 ** be running the interpreter in the build directory, so we use the
465 ** build-directory-specific logic to find Lib and such.
467 strncpy(argv0_path
, buf
, MAXPATHLEN
);
469 joinpath(argv0_path
, lib_python
);
470 joinpath(argv0_path
, LANDMARK
);
471 if (!ismodule(argv0_path
)) {
472 /* We are in the build directory so use the name of the
473 executable - we know that the absolute path is passed */
474 strncpy(argv0_path
, prog
, MAXPATHLEN
);
477 /* Use the location of the library as the progpath */
478 strncpy(argv0_path
, buf
, MAXPATHLEN
);
485 char tmpbuffer
[MAXPATHLEN
+1];
486 int linklen
= readlink(progpath
, tmpbuffer
, MAXPATHLEN
);
487 while (linklen
!= -1) {
488 /* It's not null terminated! */
489 tmpbuffer
[linklen
] = '\0';
490 if (tmpbuffer
[0] == SEP
)
491 /* tmpbuffer should never be longer than MAXPATHLEN,
492 but extra check does not hurt */
493 strncpy(argv0_path
, tmpbuffer
, MAXPATHLEN
);
495 /* Interpret relative to progpath */
497 joinpath(argv0_path
, tmpbuffer
);
499 linklen
= readlink(argv0_path
, tmpbuffer
, MAXPATHLEN
);
502 #endif /* HAVE_READLINK */
505 /* At this point, argv0_path is guaranteed to be less than
506 MAXPATHLEN bytes long.
509 if (!(pfound
= search_for_prefix(argv0_path
, home
))) {
512 "Could not find platform independent libraries <prefix>\n");
513 strncpy(prefix
, PREFIX
, MAXPATHLEN
);
514 joinpath(prefix
, lib_python
);
519 strncpy(zip_path
, prefix
, MAXPATHLEN
);
520 zip_path
[MAXPATHLEN
] = '\0';
521 if (pfound
> 0) { /* Use the reduced prefix returned by Py_GetPrefix() */
526 strncpy(zip_path
, PREFIX
, MAXPATHLEN
);
527 joinpath(zip_path
, "lib/python00.zip");
528 bufsz
= strlen(zip_path
); /* Replace "00" with version */
529 zip_path
[bufsz
- 6] = VERSION
[0];
530 zip_path
[bufsz
- 5] = VERSION
[2];
532 if (!(efound
= search_for_exec_prefix(argv0_path
, home
))) {
535 "Could not find platform dependent libraries <exec_prefix>\n");
536 strncpy(exec_prefix
, EXEC_PREFIX
, MAXPATHLEN
);
537 joinpath(exec_prefix
, "lib/lib-dynload");
539 /* If we found EXEC_PREFIX do *not* reduce it! (Yet.) */
541 if ((!pfound
|| !efound
) && !Py_FrozenFlag
)
543 "Consider setting $PYTHONHOME to <prefix>[:<exec_prefix>]\n");
545 /* Calculate size of return buffer.
550 bufsz
+= strlen(rtpypath
) + 1;
552 prefixsz
= strlen(prefix
) + 1;
555 char *delim
= strchr(defpath
, DELIM
);
557 if (defpath
[0] != SEP
)
558 /* Paths are relative to prefix */
562 bufsz
+= delim
- defpath
+ 1;
564 bufsz
+= strlen(defpath
) + 1;
570 bufsz
+= strlen(zip_path
) + 1;
571 bufsz
+= strlen(exec_prefix
) + 1;
573 /* This is the only malloc call in this file */
574 buf
= (char *)PyMem_Malloc(bufsz
);
577 /* We can't exit, so print a warning and limp along */
578 fprintf(stderr
, "Not enough memory for dynamic PYTHONPATH.\n");
579 fprintf(stderr
, "Using default static PYTHONPATH.\n");
580 module_search_path
= PYTHONPATH
;
583 /* Run-time value of $PYTHONPATH goes first */
585 strcpy(buf
, rtpypath
);
586 strcat(buf
, delimiter
);
591 /* Next is the default zip path */
592 strcat(buf
, zip_path
);
593 strcat(buf
, delimiter
);
595 /* Next goes merge of compile-time $PYTHONPATH with
596 * dynamically located prefix.
598 defpath
= pythonpath
;
600 char *delim
= strchr(defpath
, DELIM
);
602 if (defpath
[0] != SEP
) {
604 strcat(buf
, separator
);
608 size_t len
= delim
- defpath
+ 1;
609 size_t end
= strlen(buf
) + len
;
610 strncat(buf
, defpath
, len
);
614 strcat(buf
, defpath
);
619 strcat(buf
, delimiter
);
621 /* Finally, on goes the directory for dynamic-load modules */
622 strcat(buf
, exec_prefix
);
624 /* And publish the results */
625 module_search_path
= buf
;
628 /* Reduce prefix and exec_prefix to their essence,
629 * e.g. /usr/local/lib/python1.5 is reduced to /usr/local.
630 * If we're loading relative to the build directory,
631 * return the compiled-in defaults instead.
636 /* The prefix is the root directory, but reduce() chopped
639 strcpy(prefix
, separator
);
642 strncpy(prefix
, PREFIX
, MAXPATHLEN
);
649 strcpy(exec_prefix
, separator
);
652 strncpy(exec_prefix
, EXEC_PREFIX
, MAXPATHLEN
);
656 /* External interface */
661 if (!module_search_path
)
663 return module_search_path
;
669 if (!module_search_path
)
675 Py_GetExecPrefix(void)
677 if (!module_search_path
)
683 Py_GetProgramFullPath(void)
685 if (!module_search_path
)