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cosmopolitan/third_party/python/Modules/getpath.c
Justine Tunney 6f7d0cb1c3
Pay off more technical debt 
This makes breaking changes to add underscores to many non-standard
function names provided by the c library. MODE=tiny is now tinier and
we now use smaller locks that are better for tiny apps in this mode.
Some headers have been renamed to be in the same folder as the build
package, so it'll be easier to know which build dependency is needed.
Certain old misguided interfaces have been removed. Intel intrinsics
headers are now listed in libc/isystem (but not in the amalgamation)
to help further improve open source compatibility. Header complexity
has also been reduced. Lastly, more shell scripts are now available.
2022-09-12 23:36:56 -07:00

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/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:4;tab-width:8;coding:utf-8 -*-│
│vi: set net ft=c ts=4 sts=4 sw=4 fenc=utf-8 :vi│
╞══════════════════════════════════════════════════════════════════════════════╡
│ Python 3 │
│ https://docs.python.org/3/license.html │
╚─────────────────────────────────────────────────────────────────────────────*/
#include "libc/calls/calls.h"
#include "libc/calls/struct/stat.h"
#include "libc/errno.h"
#include "libc/intrin/cmpxchg.h"
#include "libc/log/log.h"
#include "libc/mem/alloca.h"
#include "libc/mem/mem.h"
#include "libc/mem/gc.internal.h"
#include "libc/runtime/runtime.h"
#include "libc/str/str.h"
#include "libc/sysv/consts/auxv.h"
#include "libc/sysv/consts/s.h"
#include "libc/x/x.h"
#include "third_party/python/Include/fileutils.h"
#include "third_party/python/Include/osdefs.h"
#include "third_party/python/Include/pyerrors.h"
#include "third_party/python/Include/pymem.h"
/* clang-format off */
/* Return the initial module search path. */
#pragma GCC diagnostic ignored "-Wunused-function" // search_for_exec_prefix
#pragma GCC diagnostic ignored "-Wunused-but-set-variable" // separator
/* 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 slashes 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 $PATH environment
* variable), the original argv[0] string is used.
*
* Next, the executable location is examined to see if it is a symbolic
* link. If so, the link is chased (correctly interpreting a relative
* pathname if one is found) and the directory of the link target is used.
*
* Finally, argv0_path is set to the directory containing the executable
* (i.e. the last component is stripped).
*
* With argv0_path in hand, we perform a number of steps. The same steps
* are performed for prefix and for exec_prefix, but with a different
* landmark.
*
* Step 1. Are we running python out of the build directory? This is
* checked by looking for a different kind of landmark relative to
* argv0_path. For prefix, the landmark's path is derived from the VPATH
* preprocessor variable (taking into account that its value is almost, but
* not quite, what we need). For exec_prefix, the landmark is
* pybuilddir.txt. If the landmark is found, we're done.
*
* For the remaining steps, the prefix landmark will always be
* lib/python$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.
*
* An embedding application can use Py_SetPath() to override all of
* these authomatic path computations.
*
* NOTE: Windows MSVC builds use PC/getpathp.c instead!
*/
wchar_t *Py_GetProgramName(void);
#if !defined(PREFIX) || !defined(EXEC_PREFIX) || !defined(VERSION) || !defined(VPATH)
#define PREFIX L"Lib"
#define EXEC_PREFIX L"build"
#define VERSION L"3.6"
#define VPATH ""
// #error "PREFIX, EXEC_PREFIX, VERSION, and VPATH must be constant defined"
#endif
#ifndef LANDMARK
#define LANDMARK L"os.py"
#endif
#define LIMITED_SEARCH_PATH L"/zip/.python"
static wchar_t *progpath;
static wchar_t *prefix = LIMITED_SEARCH_PATH;
static wchar_t *exec_prefix = LIMITED_SEARCH_PATH;
static wchar_t *module_search_path = LIMITED_SEARCH_PATH;
/* Get file status. Encode the path to the locale encoding. */
static int
_Py_wstat(const wchar_t* path, struct stat *buf)
{
int err;
char *fname;
fname = Py_EncodeLocale(path, NULL);
if (fname == NULL) {
errno = EINVAL;
return -1;
}
err = stat(fname, buf);
PyMem_Free(fname);
return err;
}
static void
reduce(wchar_t *dir)
{
size_t i = wcslen(dir);
while (i > 0 && dir[i] != SEP)
--i;
dir[i] = '\0';
}
static int
isfile(wchar_t *filename) /* Is file, not directory */
{
struct stat buf;
if (_Py_wstat(filename, &buf) != 0)
return 0;
if (!S_ISREG(buf.st_mode))
return 0;
return 1;
}
static int
ismodule(wchar_t *filename) /* Is module -- check for .pyc too */
{
if (isfile(filename))
return 1;
/* Check for the compiled version of prefix. */
if (wcslen(filename) < MAXPATHLEN) {
wcscat(filename, L"c");
if (isfile(filename))
return 1;
}
return 0;
}
static int
isxfile(wchar_t *filename) /* Is executable file */
{
struct stat buf;
if (_Py_wstat(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(wchar_t *filename) /* Is directory */
{
struct stat buf;
if (_Py_wstat(filename, &buf) != 0)
return 0;
if (!S_ISDIR(buf.st_mode))
return 0;
return 1;
}
/* 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
joinpath(wchar_t *buffer, wchar_t *stuff)
{
size_t n, k;
if (stuff[0] == SEP)
n = 0;
else {
n = wcslen(buffer);
if (n > 0 && buffer[n-1] != SEP && n < MAXPATHLEN)
buffer[n++] = SEP;
}
if (n > MAXPATHLEN)
Py_FatalError("buffer overflow in getpath.c's joinpath()");
k = wcslen(stuff);
if (n + k > MAXPATHLEN)
k = MAXPATHLEN - n;
wcsncpy(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(wchar_t *path, wchar_t *p, size_t pathlen)
{
if (p[0] == SEP)
wcscpy(path, p);
else {
if (!_Py_wgetcwd(path, pathlen)) {
/* unable to get the current directory */
wcscpy(path, p);
return;
}
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(wchar_t *path)
{
wchar_t *buffer = gc(calloc(MAXPATHLEN+1, sizeof(wchar_t)));
if (path[0] == SEP) return;
copy_absolute(buffer, path, MAXPATHLEN+1);
wcscpy(path, buffer);
}
/* search for a prefix value in an environment file. If found, copy it
to the provided buffer, which is expected to be no more than MAXPATHLEN
bytes long.
*/
static int
find_env_config_value(FILE * env_file, const wchar_t * key, wchar_t * value)
{
int result = 0; /* meaning not found */
char buffer[MAXPATHLEN*2+1]; /* allow extra for key, '=', etc. */
fseek(env_file, 0, SEEK_SET);
while (!feof(env_file)) {
char * p = fgets(buffer, MAXPATHLEN*2, env_file);
wchar_t tmpbuffer[MAXPATHLEN*2+1];
PyObject * decoded;
int n;
if (p == NULL)
break;
n = strlen(p);
if (p[n - 1] != '\n') {
/* line has overflowed - bail */
break;
}
if (p[0] == '#') /* Comment - skip */
continue;
decoded = PyUnicode_DecodeUTF8(buffer, n, "surrogateescape");
if (decoded != NULL) {
Py_ssize_t k;
wchar_t * state;
k = PyUnicode_AsWideChar(decoded,
tmpbuffer, MAXPATHLEN * 2);
Py_DECREF(decoded);
if (k >= 0) {
wchar_t * tok = wcstok(tmpbuffer, L" \t\r\n", &state);
if ((tok != NULL) && !wcscmp(tok, key)) {
tok = wcstok(NULL, L" \t", &state);
if ((tok != NULL) && !wcscmp(tok, L"=")) {
tok = wcstok(NULL, L"\r\n", &state);
if (tok != NULL) {
wcsncpy(value, tok, MAXPATHLEN);
result = 1;
break;
}
}
}
}
}
}
return result;
}
/* search_for_prefix requires that argv0_path be no more than MAXPATHLEN
bytes long.
*/
static int
search_for_prefix(wchar_t *argv0_path, wchar_t *home, wchar_t *_prefix,
wchar_t *lib_python)
{
size_t n;
wchar_t *vpath;
/* If PYTHONHOME is set, we believe it unconditionally */
if (home) {
wchar_t *delim;
wcsncpy(prefix, home, MAXPATHLEN);
prefix[MAXPATHLEN] = L'\0';
delim = wcschr(prefix, DELIM);
if (delim)
*delim = L'\0';
joinpath(prefix, lib_python);
joinpath(prefix, LANDMARK);
return 1;
}
/* Check to see if argv[0] is in the build directory */
wcsncpy(prefix, argv0_path, MAXPATHLEN);
prefix[MAXPATHLEN] = L'\0';
joinpath(prefix, L"Modules/Setup");
if (isfile(prefix)) {
/* Check VPATH to see if argv0_path is in the build directory. */
vpath = Py_DecodeLocale(VPATH, NULL);
if (vpath != NULL) {
wcsncpy(prefix, argv0_path, MAXPATHLEN);
prefix[MAXPATHLEN] = L'\0';
joinpath(prefix, vpath);
PyMem_RawFree(vpath);
joinpath(prefix, L"Lib");
joinpath(prefix, LANDMARK);
if (ismodule(prefix))
return -1;
}
}
/* Search from argv0_path, until root is found */
copy_absolute(prefix, argv0_path, MAXPATHLEN+1);
do {
n = wcslen(prefix);
joinpath(prefix, lib_python);
joinpath(prefix, LANDMARK);
if (ismodule(prefix))
return 1;
prefix[n] = L'\0';
reduce(prefix);
} while (prefix[0]);
/* Look at configure's PREFIX */
wcsncpy(prefix, _prefix, MAXPATHLEN);
prefix[MAXPATHLEN] = L'\0';
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(wchar_t *argv0_path, wchar_t *home,
wchar_t *_exec_prefix, wchar_t *lib_python)
{
size_t n;
/* If PYTHONHOME is set, we believe it unconditionally */
if (home) {
wchar_t *delim;
delim = wcschr(home, DELIM);
if (delim)
wcsncpy(exec_prefix, delim+1, MAXPATHLEN);
else
wcsncpy(exec_prefix, home, MAXPATHLEN);
exec_prefix[MAXPATHLEN] = L'\0';
joinpath(exec_prefix, lib_python);
joinpath(exec_prefix, L"lib-dynload");
return 1;
}
/* Check to see if argv[0] is in the build directory. "pybuilddir.txt"
is written by setup.py and contains the relative path to the location
of shared library modules. */
wcsncpy(exec_prefix, argv0_path, MAXPATHLEN);
exec_prefix[MAXPATHLEN] = L'\0';
joinpath(exec_prefix, L"pybuilddir.txt");
if (isfile(exec_prefix)) {
FILE *f = _Py_wfopen(exec_prefix, L"rb");
if (f == NULL)
errno = 0;
else {
char buf[MAXPATHLEN+1];
PyObject *decoded;
wchar_t rel_builddir_path[MAXPATHLEN+1];
n = fread(buf, 1, MAXPATHLEN, f);
buf[n] = '\0';
fclose(f);
decoded = PyUnicode_DecodeUTF8(buf, n, "surrogateescape");
if (decoded != NULL) {
Py_ssize_t k;
k = PyUnicode_AsWideChar(decoded,
rel_builddir_path, MAXPATHLEN);
Py_DECREF(decoded);
if (k >= 0) {
rel_builddir_path[k] = L'\0';
wcsncpy(exec_prefix, argv0_path, MAXPATHLEN);
exec_prefix[MAXPATHLEN] = L'\0';
joinpath(exec_prefix, rel_builddir_path);
return -1;
}
}
}
}
/* Search from argv0_path, until root is found */
copy_absolute(exec_prefix, argv0_path, MAXPATHLEN+1);
do {
n = wcslen(exec_prefix);
joinpath(exec_prefix, lib_python);
joinpath(exec_prefix, L"lib-dynload");
if (isdir(exec_prefix))
return 1;
exec_prefix[n] = L'\0';
reduce(exec_prefix);
} while (exec_prefix[0]);
/* Look at configure's EXEC_PREFIX */
wcsncpy(exec_prefix, _exec_prefix, MAXPATHLEN);
exec_prefix[MAXPATHLEN] = L'\0';
joinpath(exec_prefix, lib_python);
joinpath(exec_prefix, L"lib-dynload");
if (isdir(exec_prefix))
return 1;
/* Fail */
return 0;
}
static void
calculate_path(void)
{
static wchar_t delimiter[2] = {DELIM, '\0'};
static wchar_t separator[2] = {SEP, '\0'};
/* ignore PYTHONPATH/PYTHONHOME for now */
// char *_rtpypath = Py_GETENV("PYTHONPATH");
/* XXX use wide version on Windows */
// wchar_t *rtpypath = NULL;
// wchar_t *home = Py_GetPythonHome();
char *_path = getenv("PATH");
wchar_t *path_buffer = NULL;
wchar_t *path = NULL;
wchar_t *prog = Py_GetProgramName();
/* wont need zip_path because embedded stdlib inside executable */
/* wchar_t zip_path[MAXPATHLEN+1]; */
wchar_t *buf;
size_t bufsz;
size_t ape_length;
wchar_t *ape_path = gc(calloc(MAXPATHLEN+1, sizeof(wchar_t)));
wchar_t *argv0_path = gc(calloc(MAXPATHLEN+1, sizeof(wchar_t)));
wchar_t *ape_lib_path = gc(calloc(MAXPATHLEN+1, sizeof(wchar_t)));
wchar_t *ape_exec_path = gc(calloc(MAXPATHLEN+1, sizeof(wchar_t)));
wchar_t *package_path = gc(calloc(MAXPATHLEN+1, sizeof(wchar_t)));
wchar_t *ape_package_path = gc(calloc(MAXPATHLEN+1, sizeof(wchar_t)));
if (IsWindows()) {
delimiter[0] = L';';
separator[0] = L'\\';
}
if (_path) {
path_buffer = Py_DecodeLocale(_path, NULL);
path = path_buffer;
}
/* 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 (wcschr(prog, SEP)) {
wcsncpy(progpath, prog, MAXPATHLEN);
} else if (path) {
while (1) {
wchar_t *delim = wcschr(path, DELIM);
if (delim) {
size_t len = delim - path;
if (len > MAXPATHLEN)
len = MAXPATHLEN;
wcsncpy(progpath, path, len);
*(progpath + len) = '\0';
}
else
wcsncpy(progpath, path, MAXPATHLEN);
joinpath(progpath, prog);
if (isxfile(progpath))
break;
if (!delim) {
progpath[0] = L'\0';
break;
}
path = delim + 1;
}
} else {
progpath[0] = '\0';
}
PyMem_RawFree(path_buffer);
if (progpath[0] != SEP && progpath[0] != '\0')
absolutize(progpath);
wcsncpy(argv0_path, progpath, MAXPATHLEN);
argv0_path[MAXPATHLEN] = '\0';
reduce(argv0_path);
/* At this point, argv0_path is guaranteed to be less than
MAXPATHLEN bytes long.
*/
/* not searching for pyvenv.cfg */
/* Avoid absolute path for prefix */
wcsncpy(prefix,
L"third_party/python/Lib",
MAXPATHLEN);
/* wcsncpy(prefix, */
/* L"/zip/.python", */
/* MAXPATHLEN); */
/* Avoid absolute path for exec_prefix */
wcsncpy(exec_prefix, L"build/lib.linux-x86_64-3.6", MAXPATHLEN);
wcsncpy(package_path, L"Lib/site-packages", MAXPATHLEN);
/* add paths for the internal store of the APE */
if (wcslen(progpath) > 0 && wcslen(progpath) + 1 < MAXPATHLEN)
wcsncpy(ape_path, progpath, MAXPATHLEN);
else
wcsncpy(ape_path, prog, MAXPATHLEN);
ape_length = wcslen(ape_path);
wcsncpy(ape_lib_path, ape_path, MAXPATHLEN);
// extra 1 at the start for the slash
if(ape_length + 1 + wcslen(prefix) + 1 < MAXPATHLEN)
{
ape_lib_path[ape_length] = L'/';
wcscat(ape_lib_path + ape_length + 1, prefix);
}
wcsncpy(ape_exec_path, ape_path, MAXPATHLEN);
if(ape_length + 1 + wcslen(exec_prefix) + 1 < MAXPATHLEN)
{
ape_exec_path[ape_length] = L'/';
wcscat(ape_exec_path + ape_length + 1, exec_prefix);
}
wcsncpy(ape_package_path, ape_path, MAXPATHLEN);
if(ape_length + 1 + wcslen(package_path) + 1 < MAXPATHLEN)
{
ape_package_path[ape_length] = L'/';
wcscat(ape_package_path + ape_length + 1, package_path);
}
/* Calculate size of return buffer */
bufsz = 0;
bufsz += wcslen(ape_lib_path) + 1;
bufsz += wcslen(ape_exec_path) + 1;
bufsz += wcslen(ape_package_path) + 1;
bufsz += wcslen(ape_path) + 1;
bufsz += wcslen(prefix) + 1;
bufsz += wcslen(exec_prefix) + 1;
bufsz += wcslen(package_path) + 1;
/* This is the only malloc call in this file */
buf = PyMem_RawMalloc(bufsz * sizeof(wchar_t));
if (buf == NULL) {
Py_FatalError(
"Not enough memory for dynamic PYTHONPATH");
}
buf[0] = L'\0';
wcscat(buf, prefix);
wcscat(buf, delimiter);
wcscat(buf, package_path);
wcscat(buf, delimiter);
wcscat(buf, ape_lib_path);
wcscat(buf, delimiter);
wcscat(buf, ape_package_path);
wcscat(buf, delimiter);
wcscat(buf, ape_exec_path);
wcscat(buf, delimiter);
wcscat(buf, ape_path);
wcscat(buf, delimiter);
/* Finally, on goes the directory for dynamic-load modules */
wcscat(buf, exec_prefix);
/* And publish the results */
module_search_path = buf;
// printf("%ls\n", buf);
}
/* External interface */
void
Py_SetPath(const wchar_t *path)
{
if (module_search_path != NULL) {
PyMem_RawFree(module_search_path);
module_search_path = NULL;
}
if (path != NULL) {
wchar_t *prog = Py_GetProgramName();
wcsncpy(progpath, prog, MAXPATHLEN);
exec_prefix[0] = prefix[0] = L'\0';
module_search_path = PyMem_RawMalloc((wcslen(path) + 1) * sizeof(wchar_t));
if (module_search_path != NULL)
wcscpy(module_search_path, path);
}
}
wchar_t *
Py_GetPath(void)
{
if (!module_search_path)
calculate_path();
return module_search_path;
}
wchar_t *
Py_GetPrefix(void)
{
if (!module_search_path)
calculate_path();
return prefix;
}
wchar_t *
Py_GetExecPrefix(void)
{
if (!module_search_path)
calculate_path();
return exec_prefix;
}
wchar_t *
Py_GetProgramFullPath(void)
{
static bool once;
if (_cmpxchg(&once, false, true)) {
progpath = utf8to32(GetProgramExecutableName(), -1, 0);
__cxa_atexit(free, progpath, 0);
}
return progpath;
}
void
Py_LimitedPath(void)
{
prefix = wcscpy(PyMem_RawMalloc((wcslen(LIMITED_SEARCH_PATH) + 1) * 4), LIMITED_SEARCH_PATH);
exec_prefix = wcscpy(PyMem_RawMalloc((wcslen(LIMITED_SEARCH_PATH) + 1) * 4), LIMITED_SEARCH_PATH);
module_search_path = wcscpy(PyMem_RawMalloc((wcslen(LIMITED_SEARCH_PATH) + 1) * 4), LIMITED_SEARCH_PATH);
}
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