/* Return the initial module search path. */ #include "Python.h" #include "osdefs.h" #include #include #ifdef WITH_NEXT_FRAMEWORK #include #endif /* Search in some common locations for the associated Python libraries. * * Two directories must be found, the platform independent directory * (prefix), containing the common .py and .pyc files, and the platform * dependent directory (exec_prefix), containing the shared library * modules. Note that prefix and exec_prefix can be the same directory, * but for some installations, they are different. * * Py_GetPath() carries out separate searches for prefix and exec_prefix. * Each search tries a number of different locations until a ``landmark'' * file or directory is found. If no prefix or exec_prefix is found, a * warning message is issued and the preprocessor defined PREFIX and * EXEC_PREFIX are used (even though they will not work); python carries on * as best as is possible, but most imports will fail. * * Before any searches are done, the location of the executable is * determined. If argv[0] has one or more slashs in it, it is used * unchanged. Otherwise, it must have been invoked from the shell's path, * so we search $PATH for the named executable and use that. If the * executable was not found on $PATH (or there was no $PATH environment * variable), the original argv[0] string is used. * * Next, the executable location is examined to see if it is a symbolic * link. If so, the link is chased (correctly interpreting a relative * pathname if one is found) and the directory of the link target is used. * * Finally, argv0_path is set to the directory containing the executable * (i.e. the last component is stripped). * * With argv0_path in hand, we perform a number of steps. The same steps * are performed for prefix and for exec_prefix, but with a different * landmark. * * Step 1. Are we running python out of the build directory? This is * checked by looking for a different kind of landmark relative to * argv0_path. For prefix, the landmark's path is derived from the VPATH * preprocessor variable (taking into account that its value is almost, but * not quite, what we need). For exec_prefix, the landmark is * Modules/Setup. If the landmark is found, we're done. * * For the remaining steps, the prefix landmark will always be * lib/python$VERSION/os.py and the exec_prefix will always be * lib/python$VERSION/lib-dynload, where $VERSION is Python's version * number as supplied by the Makefile. Note that this means that no more * build directory checking is performed; if the first step did not find * the landmarks, the assumption is that python is running from an * installed setup. * * Step 2. See if the $PYTHONHOME environment variable points to the * installed location of the Python libraries. If $PYTHONHOME is set, then * it points to prefix and exec_prefix. $PYTHONHOME can be a single * directory, which is used for both, or the prefix and exec_prefix * directories separated by a colon. * * Step 3. Try to find prefix and exec_prefix relative to argv0_path, * backtracking up the path until it is exhausted. This is the most common * step to succeed. Note that if prefix and exec_prefix are different, * exec_prefix is more likely to be found; however if exec_prefix is a * subdirectory of prefix, both will be found. * * Step 4. Search the directories pointed to by the preprocessor variables * PREFIX and EXEC_PREFIX. These are supplied by the Makefile but can be * passed in as options to the configure script. * * That's it! * * Well, almost. Once we have determined prefix and exec_prefix, the * preprocessor variable PYTHONPATH is used to construct a path. Each * relative path on PYTHONPATH is prefixed with prefix. Then the directory * containing the shared library modules is appended. The environment * variable $PYTHONPATH is inserted in front of it all. Finally, the * prefix and exec_prefix globals are tweaked so they reflect the values * expected by other code, by stripping the "lib/python$VERSION/..." stuff * off. If either points to the build directory, the globals are reset to * the corresponding preprocessor variables (so sys.prefix will reflect the * installation location, even though sys.path points into the build * directory). This seems to make more sense given that currently the only * known use of sys.prefix and sys.exec_prefix is for the ILU installation * process to find the installed Python tree. */ #ifndef VERSION #if defined(__VMS) #define VERSION "2_1" #else #define VERSION "2.1" #endif #endif #ifndef VPATH #define VPATH "." #endif #ifndef PREFIX #define PREFIX "/usr/local" #endif #ifndef EXEC_PREFIX #define EXEC_PREFIX PREFIX #endif #ifndef PYTHONPATH #define PYTHONPATH PREFIX "/lib/python" VERSION ":" \ EXEC_PREFIX "/lib/python" VERSION "/lib-dynload" #endif #ifndef LANDMARK #define LANDMARK "os.py" #endif static char prefix[MAXPATHLEN+1]; static char exec_prefix[MAXPATHLEN+1]; static char progpath[MAXPATHLEN+1]; static char *module_search_path = NULL; static char lib_python[] = "lib/python" VERSION; static void reduce(char *dir) { size_t i = strlen(dir); while (i > 0 && dir[i] != SEP) --i; dir[i] = '\0'; } static int isfile(char *filename) /* Is file, not directory */ { struct stat buf; if (stat(filename, &buf) != 0) return 0; if (!S_ISREG(buf.st_mode)) return 0; return 1; } static int ismodule(char *filename) /* Is module -- check for .pyc/.pyo too */ { if (isfile(filename)) return 1; /* Check for the compiled version of prefix. */ if (strlen(filename) < MAXPATHLEN) { strcat(filename, Py_OptimizeFlag ? "o" : "c"); if (isfile(filename)) return 1; } return 0; } static int isxfile(char *filename) /* Is executable file */ { struct stat buf; if (stat(filename, &buf) != 0) return 0; if (!S_ISREG(buf.st_mode)) return 0; if ((buf.st_mode & 0111) == 0) return 0; return 1; } static int isdir(char *filename) /* Is directory */ { struct stat buf; if (stat(filename, &buf) != 0) return 0; if (!S_ISDIR(buf.st_mode)) return 0; return 1; } /* joinpath requires that any buffer argument passed to it has at least MAXPATHLEN + 1 bytes allocated. If this requirement is met, it guarantees that it will never overflow the buffer. If stuff is too long, buffer will contain a truncated copy of stuff. */ static void joinpath(char *buffer, char *stuff) { size_t n, k; if (stuff[0] == SEP) n = 0; else { n = strlen(buffer); if (n > 0 && buffer[n-1] != SEP && n < MAXPATHLEN) buffer[n++] = SEP; } k = strlen(stuff); if (n + k > MAXPATHLEN) k = MAXPATHLEN - n; strncpy(buffer+n, stuff, k); buffer[n+k] = '\0'; } /* copy_absolute requires that path be allocated at least MAXPATHLEN + 1 bytes and that p be no more than MAXPATHLEN bytes. */ static void copy_absolute(char *path, char *p) { if (p[0] == SEP) strcpy(path, p); else { getcwd(path, MAXPATHLEN); if (p[0] == '.' && p[1] == SEP) p += 2; joinpath(path, p); } } /* absolutize() requires that path be allocated at least MAXPATHLEN+1 bytes. */ static void absolutize(char *path) { char buffer[MAXPATHLEN + 1]; if (path[0] == SEP) return; copy_absolute(buffer, path); strcpy(path, buffer); } /* search_for_prefix requires that argv0_path be no more than MAXPATHLEN bytes long. */ static int search_for_prefix(char *argv0_path, char *home) { size_t n; char *vpath; /* If PYTHONHOME is set, we believe it unconditionally */ if (home) { char *delim; strncpy(prefix, home, MAXPATHLEN); delim = strchr(prefix, DELIM); if (delim) *delim = '\0'; joinpath(prefix, lib_python); joinpath(prefix, LANDMARK); return 1; } /* Check to see if argv[0] is in the build directory */ strcpy(prefix, argv0_path); joinpath(prefix, "Modules/Setup"); if (isfile(prefix)) { /* Check VPATH to see if argv0_path is in the build directory. */ vpath = VPATH; strcpy(prefix, argv0_path); joinpath(prefix, vpath); joinpath(prefix, "Lib"); joinpath(prefix, LANDMARK); if (ismodule(prefix)) return -1; } /* Search from argv0_path, until root is found */ copy_absolute(prefix, argv0_path); do { n = strlen(prefix); joinpath(prefix, lib_python); joinpath(prefix, LANDMARK); if (ismodule(prefix)) return 1; prefix[n] = '\0'; reduce(prefix); } while (prefix[0]); /* Look at configure's PREFIX */ strncpy(prefix, PREFIX, MAXPATHLEN); joinpath(prefix, lib_python); joinpath(prefix, LANDMARK); if (ismodule(prefix)) return 1; /* Fail */ return 0; } /* search_for_exec_prefix requires that argv0_path be no more than MAXPATHLEN bytes long. */ static int search_for_exec_prefix(char *argv0_path, char *home) { size_t n; /* If PYTHONHOME is set, we believe it unconditionally */ if (home) { char *delim; delim = strchr(home, DELIM); if (delim) strncpy(exec_prefix, delim+1, MAXPATHLEN); else strncpy(exec_prefix, home, MAXPATHLEN); joinpath(exec_prefix, lib_python); joinpath(exec_prefix, "lib-dynload"); return 1; } /* Check to see if argv[0] is in the build directory */ strcpy(exec_prefix, argv0_path); joinpath(exec_prefix, "Modules/Setup"); if (isfile(exec_prefix)) { reduce(exec_prefix); return -1; } /* Search from argv0_path, until root is found */ copy_absolute(exec_prefix, argv0_path); do { n = strlen(exec_prefix); joinpath(exec_prefix, lib_python); joinpath(exec_prefix, "lib-dynload"); if (isdir(exec_prefix)) return 1; exec_prefix[n] = '\0'; reduce(exec_prefix); } while (exec_prefix[0]); /* Look at configure's EXEC_PREFIX */ strncpy(exec_prefix, EXEC_PREFIX, MAXPATHLEN); joinpath(exec_prefix, lib_python); joinpath(exec_prefix, "lib-dynload"); if (isdir(exec_prefix)) return 1; /* Fail */ return 0; } static void calculate_path(void) { extern char *Py_GetProgramName(void); static char delimiter[2] = {DELIM, '\0'}; static char separator[2] = {SEP, '\0'}; char *pythonpath = PYTHONPATH; char *rtpypath = Py_GETENV("PYTHONPATH"); char *home = Py_GetPythonHome(); char *path = getenv("PATH"); char *prog = Py_GetProgramName(); char argv0_path[MAXPATHLEN+1]; int pfound, efound; /* 1 if found; -1 if found build directory */ char *buf; size_t bufsz; size_t prefixsz; char *defpath = pythonpath; #ifdef WITH_NEXT_FRAMEWORK NSModule pythonModule; #endif /* 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. */ if (strchr(prog, SEP)) strncpy(progpath, prog, MAXPATHLEN); else if (path) { while (1) { char *delim = strchr(path, DELIM); if (delim) { size_t len = delim - path; if (len > MAXPATHLEN) len = MAXPATHLEN; strncpy(progpath, path, len); *(progpath + len) = '\0'; } else strncpy(progpath, path, MAXPATHLEN); joinpath(progpath, prog); if (isxfile(progpath)) break; if (!delim) { progpath[0] = '\0'; break; } path = delim + 1; } } else progpath[0] = '\0'; if (progpath[0] != SEP) absolutize(progpath); strncpy(argv0_path, progpath, MAXPATHLEN); argv0_path[MAXPATHLEN] = '\0'; #ifdef WITH_NEXT_FRAMEWORK /* On Mac OS X we have a special case if we're running from a framework. ** This is because the python home should be set relative to the library, ** which is in the framework, not relative to the executable, which may ** be outside of the framework. Except when we're in the build directory... */ pythonModule = NSModuleForSymbol(NSLookupAndBindSymbol("_Py_Initialize")); /* Use dylib functions to find out where the framework was loaded from */ buf = NSLibraryNameForModule(pythonModule); if (buf != NULL) { /* We're in a framework. */ /* See if we might be in the build directory. The framework in the ** build directory is incomplete, it only has the .dylib and a few ** needed symlinks, it doesn't have the Lib directories and such. ** If we're running with the framework from the build directory we must ** be running the interpreter in the build directory, so we use the ** build-directory-specific logic to find Lib and such. */ strncpy(argv0_path, buf, MAXPATHLEN); reduce(argv0_path); joinpath(argv0_path, lib_python); joinpath(argv0_path, LANDMARK); if (!ismodule(argv0_path)) { /* We are in the build directory so use the name of the executable - we know that the absolute path is passed */ strncpy(argv0_path, prog, MAXPATHLEN); } else { /* Use the location of the library as the progpath */ strncpy(argv0_path, buf, MAXPATHLEN); } } #endif #if HAVE_READLINK { char tmpbuffer[MAXPATHLEN+1]; int linklen = readlink(progpath, tmpbuffer, MAXPATHLEN); while (linklen != -1) { /* It's not null terminated! */ tmpbuffer[linklen] = '\0'; if (tmpbuffer[0] == SEP) /* tmpbuffer should never be longer than MAXPATHLEN, but extra check does not hurt */ strncpy(argv0_path, tmpbuffer, MAXPATHLEN); else { /* Interpret relative to progpath */ reduce(argv0_path); joinpath(argv0_path, tmpbuffer); } linklen = readlink(argv0_path, tmpbuffer, MAXPATHLEN); } } #endif /* HAVE_READLINK */ reduce(argv0_path); /* At this point, argv0_path is guaranteed to be less than MAXPATHLEN bytes long. */ if (!(pfound = search_for_prefix(argv0_path, home))) { if (!Py_FrozenFlag) fprintf(stderr, "Could not find platform independent libraries \n"); strncpy(prefix, PREFIX, MAXPATHLEN); joinpath(prefix, lib_python); } else reduce(prefix); if (!(efound = search_for_exec_prefix(argv0_path, home))) { if (!Py_FrozenFlag) fprintf(stderr, "Could not find platform dependent libraries \n"); strncpy(exec_prefix, EXEC_PREFIX, MAXPATHLEN); joinpath(exec_prefix, "lib/lib-dynload"); } /* If we found EXEC_PREFIX do *not* reduce it! (Yet.) */ if ((!pfound || !efound) && !Py_FrozenFlag) fprintf(stderr, "Consider setting $PYTHONHOME to [:]\n"); /* Calculate size of return buffer. */ bufsz = 0; if (rtpypath) bufsz += strlen(rtpypath) + 1; prefixsz = strlen(prefix) + 1; while (1) { char *delim = strchr(defpath, DELIM); if (defpath[0] != SEP) /* Paths are relative to prefix */ bufsz += prefixsz; if (delim) bufsz += delim - defpath + 1; else { bufsz += strlen(defpath) + 1; break; } defpath = delim + 1; } bufsz += strlen(exec_prefix) + 1; /* This is the only malloc call in this file */ buf = PyMem_Malloc(bufsz); if (buf == NULL) { /* We can't exit, so print a warning and limp along */ fprintf(stderr, "Not enough memory for dynamic PYTHONPATH.\n"); fprintf(stderr, "Using default static PYTHONPATH.\n"); module_search_path = PYTHONPATH; } else { /* Run-time value of $PYTHONPATH goes first */ if (rtpypath) { strcpy(buf, rtpypath); strcat(buf, delimiter); } else buf[0] = '\0'; /* Next goes merge of compile-time $PYTHONPATH with * dynamically located prefix. */ defpath = pythonpath; while (1) { char *delim = strchr(defpath, DELIM); if (defpath[0] != SEP) { strcat(buf, prefix); strcat(buf, separator); } if (delim) { size_t len = delim - defpath + 1; size_t end = strlen(buf) + len; strncat(buf, defpath, len); *(buf + end) = '\0'; } else { strcat(buf, defpath); break; } defpath = delim + 1; } strcat(buf, delimiter); /* Finally, on goes the directory for dynamic-load modules */ strcat(buf, exec_prefix); /* And publish the results */ module_search_path = buf; } /* Reduce prefix and exec_prefix to their essence, * e.g. /usr/local/lib/python1.5 is reduced to /usr/local. * If we're loading relative to the build directory, * return the compiled-in defaults instead. */ if (pfound > 0) { reduce(prefix); reduce(prefix); } else strncpy(prefix, PREFIX, MAXPATHLEN); if (efound > 0) { reduce(exec_prefix); reduce(exec_prefix); reduce(exec_prefix); } else strncpy(exec_prefix, EXEC_PREFIX, MAXPATHLEN); } /* 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) { if (!module_search_path) calculate_path(); return exec_prefix; } char * Py_GetProgramFullPath(void) { if (!module_search_path) calculate_path(); return progpath; }