bpo-45211: Move helpers from getpath.c to internal API. by ericsnowcurrently · Pull Request #28550 · python/cpython

Expand Up @@ -82,6 +82,7 @@ #include "Python.h" #include "pycore_initconfig.h" // PyStatus #include "pycore_pathconfig.h" // _PyPathConfig #include "pycore_fileutils.h" // _Py_add_relfile() #include "osdefs.h" // SEP, ALTSEP #include <wchar.h>
Expand Down Expand Up @@ -115,10 +116,6 @@ * with a semicolon separated path prior to calling Py_Initialize. */
#ifndef LANDMARK # define LANDMARK L"lib\\os.py" #endif
#define INIT_ERR_BUFFER_OVERFLOW() _PyStatus_ERR("buffer overflow")

Expand Down Expand Up @@ -216,7 +213,7 @@ exists(const wchar_t *filename) Assumes 'filename' MAXPATHLEN+1 bytes long - may extend 'filename' by one character. */ static int ismodule(wchar_t *filename, int update_filename) ismodule(wchar_t *filename) { size_t n;
Expand All @@ -231,9 +228,8 @@ ismodule(wchar_t *filename, int update_filename) filename[n] = L'c'; filename[n + 1] = L'\0'; exist = exists(filename); if (!update_filename) { filename[n] = L'\0'; } // Drop the 'c' we just added. filename[n] = L'\0'; return exist; } return 0; Expand All @@ -253,7 +249,7 @@ ismodule(wchar_t *filename, int update_filename) static void join(wchar_t *buffer, const wchar_t *stuff) { if (FAILED(PathCchCombineEx(buffer, MAXPATHLEN+1, buffer, stuff, 0))) { if (_Py_add_relfile(buffer, stuff, MAXPATHLEN+1) < 0) { Py_FatalError("buffer overflow in getpathp.c's join()"); } } Expand All @@ -273,30 +269,37 @@ canonicalize(wchar_t *buffer, const wchar_t *path) return _PyStatus_OK(); }

/* 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(const wchar_t *prefix, const wchar_t *landmark) is_stdlibdir(wchar_t *stdlibdir) { wchar_t filename[MAXPATHLEN+1]; memset(filename, 0, sizeof(filename)); wcscpy_s(filename, Py_ARRAY_LENGTH(filename), prefix); join(filename, landmark); return ismodule(filename, FALSE); wchar_t *filename = stdlibdir; #ifndef LANDMARK # define LANDMARK L"os.py" #endif /* join() ensures 'landmark' can not overflow prefix if too long. */ join(filename, LANDMARK); return ismodule(filename); }

/* assumes argv0_path is MAXPATHLEN+1 bytes long, already \0 term'd. assumption provided by only caller, calculate_path() */ static int search_for_prefix(wchar_t *prefix, const wchar_t *argv0_path, const wchar_t *landmark) search_for_prefix(wchar_t *prefix, const wchar_t *argv0_path) { /* Search from argv0_path, until landmark is found */ wcscpy_s(prefix, MAXPATHLEN + 1, argv0_path); /* Search from argv0_path, until LANDMARK is found. We guarantee 'prefix' is null terminated in bounds. */ wcscpy_s(prefix, MAXPATHLEN+1, argv0_path); wchar_t stdlibdir[MAXPATHLEN+1]; wcscpy_s(stdlibdir, Py_ARRAY_LENGTH(stdlibdir), prefix); /* We initialize with the longest possible path, in case it doesn't fit. This also gives us an initial SEP at stdlibdir[wcslen(prefix)]. */ join(stdlibdir, L"lib"); do { if (gotlandmark(prefix, landmark)) { assert(stdlibdir[wcslen(prefix)] == SEP); /* Due to reduce() and our initial value, this result is guaranteed to fit. */ wcscpy(&stdlibdir[wcslen(prefix) + 1], L"lib"); if (is_stdlibdir(stdlibdir)) { return 1; } reduce(prefix); Expand Down Expand Up @@ -758,7 +761,7 @@ calculate_home_prefix(PyCalculatePath *calculate, reduce(prefix); calculate->home = prefix; } else if (search_for_prefix(prefix, argv0_path, LANDMARK)) { else if (search_for_prefix(prefix, argv0_path)) { calculate->home = prefix; } else { Expand Down Expand Up @@ -936,7 +939,7 @@ calculate_module_search_path(PyCalculatePath *calculate, lookBuf[nchars] = L'\0'; /* Up one level to the parent */ reduce(lookBuf); if (search_for_prefix(prefix, lookBuf, LANDMARK)) { if (search_for_prefix(prefix, lookBuf)) { break; } /* If we are out of paths to search - give up */ Expand Down