cpython/Python/import.c at 2.7 · python-emscripten/cpython · GitHub

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/* Module definition and import implementation */

#include "Python.h"

#include "Python-ast.h"

#undef Yield /* undefine macro conflicting with winbase.h */

#include "pyarena.h"

#include "pythonrun.h"

#include "errcode.h"

#include "marshal.h"

#include "code.h"

#include "compile.h"

#include "eval.h"

#include "osdefs.h"

#include "importdl.h"

#ifdef HAVE_FCNTL_H

#include <fcntl.h>

#endif

#ifdef __cplusplus

extern "C" {

#endif

#ifdef MS_WINDOWS

/* for stat.st_mode */

typedef unsigned short mode_t;

#endif

/* Magic word to reject .pyc files generated by other Python versions.

It should change for each incompatible change to the bytecode.

The value of CR and LF is incorporated so if you ever read or write

a .pyc file in text mode the magic number will be wrong; also, the

Apple MPW compiler swaps their values, botching string constants.

The magic numbers must be spaced apart atleast 2 values, as the

-U interpeter flag will cause MAGIC+1 being used. They have been

odd numbers for some time now.

There were a variety of old schemes for setting the magic number.

The current working scheme is to increment the previous value by

10.

Known values:

Python 1.5: 20121

Python 1.5.1: 20121

Python 1.5.2: 20121

Python 1.6: 50428

Python 2.0: 50823

Python 2.0.1: 50823

Python 2.1: 60202

Python 2.1.1: 60202

Python 2.1.2: 60202

Python 2.2: 60717

Python 2.3a0: 62011

Python 2.3a0: 62021

Python 2.3a0: 62011 (!)

Python 2.4a0: 62041

Python 2.4a3: 62051

Python 2.4b1: 62061

Python 2.5a0: 62071

Python 2.5a0: 62081 (ast-branch)

Python 2.5a0: 62091 (with)

Python 2.5a0: 62092 (changed WITH_CLEANUP opcode)

Python 2.5b3: 62101 (fix wrong code: for x, in ...)

Python 2.5b3: 62111 (fix wrong code: x += yield)

Python 2.5c1: 62121 (fix wrong lnotab with for loops and

storing constants that should have been removed)

Python 2.5c2: 62131 (fix wrong code: for x, in ... in listcomp/genexp)

Python 2.6a0: 62151 (peephole optimizations and STORE_MAP opcode)

Python 2.6a1: 62161 (WITH_CLEANUP optimization)

Python 2.7a0: 62171 (optimize list comprehensions/change LIST_APPEND)

Python 2.7a0: 62181 (optimize conditional branches:

introduce POP_JUMP_IF_FALSE and POP_JUMP_IF_TRUE)

Python 2.7a0 62191 (introduce SETUP_WITH)

Python 2.7a0 62201 (introduce BUILD_SET)

Python 2.7a0 62211 (introduce MAP_ADD and SET_ADD)

#define MAGIC (62211 | ((long)'\r'<<16) | ((long)'\n'<<24))

/* Magic word as global; note that _PyImport_Init() can change the

value of this global to accommodate for alterations of how the

compiler works which are enabled by command line switches. */

static long pyc_magic = MAGIC;

/* See _PyImport_FixupExtension() below */

static PyObject *extensions = NULL;

/* This table is defined in config.c: */

extern struct _inittab _PyImport_Inittab[];

struct _inittab *PyImport_Inittab = _PyImport_Inittab;

/* these tables define the module suffixes that Python recognizes */

struct filedescr * _PyImport_Filetab = NULL;

#ifdef RISCOS

static const struct filedescr _PyImport_StandardFiletab[] = {

{"/py", "U", PY_SOURCE},

{"/pyc", "rb", PY_COMPILED},

{0, 0}

};

#else

static const struct filedescr _PyImport_StandardFiletab[] = {

{".py", "U", PY_SOURCE},

#ifdef MS_WINDOWS

{".pyw", "U", PY_SOURCE},

#endif

{".pyc", "rb", PY_COMPILED},

{0, 0}

};

#endif

#ifdef MS_WINDOWS

static int isdir(char *path) {

DWORD rv;

/* see issue1293 and issue3677:

* stat() on Windows doesn't recognise paths like

* "e:\\shared\\" and "\\\\whiterab-c2znlh\\shared" as dirs.

* Also reference issue6727:

* stat() on Windows is broken and doesn't resolve symlinks properly.

rv = GetFileAttributesA(path);

return rv != INVALID_FILE_ATTRIBUTES && rv & FILE_ATTRIBUTE_DIRECTORY;

}

#else

#ifdef HAVE_STAT

static int isdir(char *path) {

struct stat statbuf;

return stat(path, &statbuf) == 0 && S_ISDIR(statbuf.st_mode);

}

#else

#ifdef RISCOS

/* with RISCOS, isdir is in unixstuff */

#else

int isdir(char *path) {

return 0;

}

#endif /* RISCOS */

#endif /* HAVE_STAT */

#endif /* MS_WINDOWS */

/* Initialize things */

void

_PyImport_Init(void)

{

const struct filedescr *scan;

struct filedescr *filetab;

int countD = 0;

int countS = 0;

/* prepare _PyImport_Filetab: copy entries from

_PyImport_DynLoadFiletab and _PyImport_StandardFiletab.

#ifdef HAVE_DYNAMIC_LOADING

for (scan = _PyImport_DynLoadFiletab; scan->suffix != NULL; ++scan)

++countD;

#endif

for (scan = _PyImport_StandardFiletab; scan->suffix != NULL; ++scan)

++countS;

filetab = PyMem_NEW(struct filedescr, countD + countS + 1);

if (filetab == NULL)

Py_FatalError("Can't initialize import file table.");

#ifdef HAVE_DYNAMIC_LOADING

memcpy(filetab, _PyImport_DynLoadFiletab,

countD * sizeof(struct filedescr));

#endif

memcpy(filetab + countD, _PyImport_StandardFiletab,

countS * sizeof(struct filedescr));

filetab[countD + countS].suffix = NULL;

_PyImport_Filetab = filetab;

if (Py_OptimizeFlag) {

/* Replace ".pyc" with ".pyo" in _PyImport_Filetab */

for (; filetab->suffix != NULL; filetab++) {

#ifndef RISCOS

if (strcmp(filetab->suffix, ".pyc") == 0)

filetab->suffix = ".pyo";

#else

if (strcmp(filetab->suffix, "/pyc") == 0)

filetab->suffix = "/pyo";

#endif

}

if (Py_UnicodeFlag) {

/* Fix the pyc_magic so that byte compiled code created

using the all-Unicode method doesn't interfere with

code created in normal operation mode. */

pyc_magic = MAGIC + 1;

}

void

_PyImportHooks_Init(void)

{

PyObject *v, *path_hooks = NULL, *zimpimport;

int err = 0;

/* adding sys.path_hooks and sys.path_importer_cache, setting up

zipimport */

if (PyType_Ready(&PyNullImporter_Type) < 0)

goto error;

if (Py_VerboseFlag)

PySys_WriteStderr("# installing zipimport hook\n");

v = PyList_New(0);

if (v == NULL)

goto error;

err = PySys_SetObject("meta_path", v);

Py_DECREF(v);

if (err)

goto error;

v = PyDict_New();

if (v == NULL)

goto error;

err = PySys_SetObject("path_importer_cache", v);

Py_DECREF(v);

if (err)

goto error;

path_hooks = PyList_New(0);

if (path_hooks == NULL)

goto error;

err = PySys_SetObject("path_hooks", path_hooks);

if (err) {

error:

PyErr_Print();

Py_FatalError("initializing sys.meta_path, sys.path_hooks, "

"path_importer_cache, or NullImporter failed"

);

}

zimpimport = PyImport_ImportModule("zipimport");

if (zimpimport == NULL) {

PyErr_Clear(); /* No zip import module -- okay */

if (Py_VerboseFlag)

PySys_WriteStderr("# can't import zipimport\n");

}

else {

PyObject *zipimporter = PyObject_GetAttrString(zimpimport,

"zipimporter");

Py_DECREF(zimpimport);

if (zipimporter == NULL) {

PyErr_Clear(); /* No zipimporter object -- okay */

if (Py_VerboseFlag)

PySys_WriteStderr(

"# can't import zipimport.zipimporter\n");

}

else {

/* sys.path_hooks.append(zipimporter) */

err = PyList_Append(path_hooks, zipimporter);

Py_DECREF(zipimporter);

if (err)

goto error;

if (Py_VerboseFlag)

PySys_WriteStderr(

"# installed zipimport hook\n");

}

Py_DECREF(path_hooks);

}

void

_PyImport_Fini(void)

{

Py_XDECREF(extensions);

extensions = NULL;

PyMem_DEL(_PyImport_Filetab);

_PyImport_Filetab = NULL;

}

/* Locking primitives to prevent parallel imports of the same module

in different threads to return with a partially loaded module.

These calls are serialized by the global interpreter lock. */

#ifdef WITH_THREAD

#include "pythread.h"

static PyThread_type_lock import_lock = 0;

static long import_lock_thread = -1;

static int import_lock_level = 0;

void

_PyImport_AcquireLock(void)

{

long me = PyThread_get_thread_ident();

if (me == -1)

return; /* Too bad */

if (import_lock == NULL) {

import_lock = PyThread_allocate_lock();

if (import_lock == NULL)

return; /* Nothing much we can do. */

}

if (import_lock_thread == me) {

import_lock_level++;

return;

}

if (import_lock_thread != -1 || !PyThread_acquire_lock(import_lock, 0))

{

PyThreadState *tstate = PyEval_SaveThread();

PyThread_acquire_lock(import_lock, 1);

PyEval_RestoreThread(tstate);

}

import_lock_thread = me;

import_lock_level = 1;

}

int

_PyImport_ReleaseLock(void)

{

long me = PyThread_get_thread_ident();

if (me == -1 || import_lock == NULL)

return 0; /* Too bad */

if (import_lock_thread != me)

return -1;

import_lock_level--;

if (import_lock_level == 0) {

import_lock_thread = -1;

PyThread_release_lock(import_lock);

}

return 1;

}

/* This function is called from PyOS_AfterFork to ensure that newly

created child processes do not share locks with the parent.

We now acquire the import lock around fork() calls but on some platforms

(Solaris 9 and earlier? see isue7242) that still left us with problems. */

void

_PyImport_ReInitLock(void)

{

if (import_lock != NULL) {

import_lock = PyThread_allocate_lock();

if (import_lock == NULL) {

Py_FatalError("PyImport_ReInitLock failed to create a new lock");

}

import_lock_thread = -1;

import_lock_level = 0;

}

#endif

static PyObject *

imp_lock_held(PyObject *self, PyObject *noargs)

{

#ifdef WITH_THREAD

return PyBool_FromLong(import_lock_thread != -1);

#else

return PyBool_FromLong(0);

#endif

}

static PyObject *

imp_acquire_lock(PyObject *self, PyObject *noargs)

{

#ifdef WITH_THREAD

_PyImport_AcquireLock();

#endif

Py_INCREF(Py_None);

return Py_None;

}

static PyObject *

imp_release_lock(PyObject *self, PyObject *noargs)

{

#ifdef WITH_THREAD

if (_PyImport_ReleaseLock() < 0) {

PyErr_SetString(PyExc_RuntimeError,

"not holding the import lock");

return NULL;

}

#endif

Py_INCREF(Py_None);

return Py_None;

}

static void

imp_modules_reloading_clear(void)

{

PyInterpreterState *interp = PyThreadState_Get()->interp;

if (interp->modules_reloading != NULL)

PyDict_Clear(interp->modules_reloading);

}

/* Helper for sys */

PyObject *

PyImport_GetModuleDict(void)

{

PyInterpreterState *interp = PyThreadState_GET()->interp;

if (interp->modules == NULL)

Py_FatalError("PyImport_GetModuleDict: no module dictionary!");

return interp->modules;

}

/* List of names to clear in sys */

static char* sys_deletes[] = {

"path", "argv", "ps1", "ps2", "exitfunc",

"exc_type", "exc_value", "exc_traceback",

"last_type", "last_value", "last_traceback",

"path_hooks", "path_importer_cache", "meta_path",

/* misc stuff */

"flags", "float_info",

NULL

};

static char* sys_files[] = {

"stdin", "__stdin__",

"stdout", "__stdout__",

"stderr", "__stderr__",

NULL

};

/* Un-initialize things, as good as we can */

void

PyImport_Cleanup(void)

{

Py_ssize_t pos, ndone;

char *name;

PyObject *key, *value, *dict;

PyInterpreterState *interp = PyThreadState_GET()->interp;

PyObject *modules = interp->modules;

if (modules == NULL)

return; /* Already done */

/* Delete some special variables first. These are common

places where user values hide and people complain when their

destructors fail. Since the modules containing them are

deleted *last* of all, they would come too late in the normal

destruction order. Sigh. */

value = PyDict_GetItemString(modules, "__builtin__");

if (value != NULL && PyModule_Check(value)) {

dict = PyModule_GetDict(value);

if (Py_VerboseFlag)

PySys_WriteStderr("# clear __builtin__._\n");

if (PyDict_SetItemString(dict, "_", Py_None) < 0) {

PyErr_Clear();

}

value = PyDict_GetItemString(modules, "sys");

if (value != NULL && PyModule_Check(value)) {

char **p;

PyObject *v;

dict = PyModule_GetDict(value);

for (p = sys_deletes; *p != NULL; p++) {

if (Py_VerboseFlag)

PySys_WriteStderr("# clear sys.%s\n", *p);

if (PyDict_SetItemString(dict, *p, Py_None) < 0) {

PyErr_Clear();

}

for (p = sys_files; *p != NULL; p+=2) {

if (Py_VerboseFlag)

PySys_WriteStderr("# restore sys.%s\n", *p);

v = PyDict_GetItemString(dict, *(p+1));

if (v == NULL)

v = Py_None;

if (PyDict_SetItemString(dict, *p, v) < 0) {

PyErr_Clear();

}

/* First, delete __main__ */

value = PyDict_GetItemString(modules, "__main__");

if (value != NULL && PyModule_Check(value)) {

if (Py_VerboseFlag)

PySys_WriteStderr("# cleanup __main__\n");

_PyModule_Clear(value);

if (PyDict_SetItemString(modules, "__main__", Py_None) < 0) {

PyErr_Clear();

}

/* The special treatment of __builtin__ here is because even

when it's not referenced as a module, its dictionary is

referenced by almost every module's __builtins__. Since

deleting a module clears its dictionary (even if there are

references left to it), we need to delete the __builtin__

module last. Likewise, we don't delete sys until the very

end because it is implicitly referenced (e.g. by print).

Also note that we 'delete' modules by replacing their entry

in the modules dict with None, rather than really deleting

them; this avoids a rehash of the modules dictionary and

also marks them as "non existent" so they won't be

re-imported. */

/* Next, repeatedly delete modules with a reference count of

one (skipping __builtin__ and sys) and delete them */

do {

ndone = 0;

pos = 0;

while (PyDict_Next(modules, &pos, &key, &value)) {

if (value->ob_refcnt != 1)

continue;

if (PyString_Check(key) && PyModule_Check(value)) {

name = PyString_AS_STRING(key);

if (strcmp(name, "__builtin__") == 0)

continue;

if (strcmp(name, "sys") == 0)

continue;

if (Py_VerboseFlag)

PySys_WriteStderr(

"# cleanup[1] %s\n", name);

_PyModule_Clear(value);

if (PyDict_SetItem(modules, key, Py_None) < 0) {

PyErr_Clear();

}

ndone++;

}

if (PyErr_Occurred()) {

PyErr_Clear();

}

} while (ndone > 0);

/* Next, delete all modules (still skipping __builtin__ and sys) */

pos = 0;

while (PyDict_Next(modules, &pos, &key, &value)) {

if (PyString_Check(key) && PyModule_Check(value)) {

name = PyString_AS_STRING(key);

if (strcmp(name, "__builtin__") == 0)

continue;

if (strcmp(name, "sys") == 0)

continue;

if (Py_VerboseFlag)

PySys_WriteStderr("# cleanup[2] %s\n", name);

_PyModule_Clear(value);

if (PyDict_SetItem(modules, key, Py_None) < 0) {

PyErr_Clear();

}

if (PyErr_Occurred()) {

PyErr_Clear();

}

/* Next, delete sys and __builtin__ (in that order) */

value = PyDict_GetItemString(modules, "sys");

if (value != NULL && PyModule_Check(value)) {

if (Py_VerboseFlag)

PySys_WriteStderr("# cleanup sys\n");

_PyModule_Clear(value);

if (PyDict_SetItemString(modules, "sys", Py_None) < 0) {

PyErr_Clear();

}

value = PyDict_GetItemString(modules, "__builtin__");

if (value != NULL && PyModule_Check(value)) {

if (Py_VerboseFlag)

PySys_WriteStderr("# cleanup __builtin__\n");

_PyModule_Clear(value);

if (PyDict_SetItemString(modules, "__builtin__", Py_None) < 0) {

PyErr_Clear();

}

/* Finally, clear and delete the modules directory */

PyDict_Clear(modules);

interp->modules = NULL;

Py_DECREF(modules);

Py_CLEAR(interp->modules_reloading);

}

/* Helper for pythonrun.c -- return magic number */

long

PyImport_GetMagicNumber(void)

{

return pyc_magic;

}

/* Magic for extension modules (built-in as well as dynamically

loaded). To prevent initializing an extension module more than

once, we keep a static dictionary 'extensions' keyed by module name

(for built-in modules) or by filename (for dynamically loaded

modules), containing these modules. A copy of the module's

dictionary is stored by calling _PyImport_FixupExtension()

immediately after the module initialization function succeeds. A

copy can be retrieved from there by calling

_PyImport_FindExtension(). */

PyObject *

_PyImport_FixupExtension(char *name, char *filename)

{

PyObject *modules, *mod, *dict, *copy;

if (extensions == NULL) {

extensions = PyDict_New();

if (extensions == NULL)

return NULL;

}

modules = PyImport_GetModuleDict();

mod = PyDict_GetItemString(modules, name);

if (mod == NULL || !PyModule_Check(mod)) {

PyErr_Format(PyExc_SystemError,

"_PyImport_FixupExtension: module %.200s not loaded", name);

return NULL;

}

dict = PyModule_GetDict(mod);

if (dict == NULL)

return NULL;

copy = PyDict_Copy(dict);

if (copy == NULL)

return NULL;

PyDict_SetItemString(extensions, filename, copy);

Py_DECREF(copy);

return copy;

}

PyObject *

_PyImport_FindExtension(char *name, char *filename)

{

PyObject *dict, *mod, *mdict;

if (extensions == NULL)

return NULL;

dict = PyDict_GetItemString(extensions, filename);

if (dict == NULL)

return NULL;

mod = PyImport_AddModule(name);

if (mod == NULL)

return NULL;

mdict = PyModule_GetDict(mod);

if (mdict == NULL)

return NULL;

if (PyDict_Update(mdict, dict))

return NULL;

if (Py_VerboseFlag)

PySys_WriteStderr("import %s # previously loaded (%s)\n",

name, filename);

return mod;

}

/* Get the module object corresponding to a module name.

First check the modules dictionary if there's one there,

if not, create a new one and insert it in the modules dictionary.

Because the former action is most common, THIS DOES NOT RETURN A

'NEW' REFERENCE! */

static PyObject *

_PyImport_AddModuleObject(PyObject *name)

{

PyObject *modules = PyImport_GetModuleDict();

PyObject *m;

if ((m = _PyDict_GetItemWithError(modules, name)) != NULL &&

PyModule_Check(m)) {

return m;

}

if (PyErr_Occurred()) {

return NULL;

}

m = PyModule_New(PyString_AS_STRING(name));

if (m == NULL) {

return NULL;

}

if (PyDict_SetItem(modules, name, m) != 0) {

Py_DECREF(m);

return NULL;

}

assert(Py_REFCNT(m) > 1);

Py_DECREF(m); /* Yes, it still exists, in modules! */

return m;

}

PyObject *

PyImport_AddModule(const char *name)

{

PyObject *nameobj, *module;

nameobj = PyString_FromString(name);

if (nameobj == NULL)

return NULL;

module = _PyImport_AddModuleObject(nameobj);

Py_DECREF(nameobj);

return module;

}

/* Remove name from sys.modules, if it's there. */

static void

remove_module(const char *name)

{

PyObject *modules = PyImport_GetModuleDict();

if (PyDict_GetItemString(modules, name) == NULL)

return;

if (PyDict_DelItemString(modules, name) < 0)

Py_FatalError("import: deleting existing key in "

"sys.modules failed");

}

/* Execute a code object in a module and return the module object

* WITH INCREMENTED REFERENCE COUNT. If an error occurs, name is

* removed from sys.modules, to avoid leaving damaged module objects

* in sys.modules. The caller may wish to restore the original

* module object (if any) in this case; PyImport_ReloadModule is an

* example.

PyObject *

PyImport_ExecCodeModule(char *name, PyObject *co)

{

return PyImport_ExecCodeModuleEx(name, co, (char *)NULL);

}

PyObject *

PyImport_ExecCodeModuleEx(char *name, PyObject *co, char *pathname)

{

PyObject *modules = PyImport_GetModuleDict();

PyObject *m, *d, *v;

m = PyImport_AddModule(name);

if (m == NULL)

return NULL;

/* If the module is being reloaded, we get the old module back

and re-use its dict to exec the new code. */

d = PyModule_GetDict(m);

if (PyDict_GetItemString(d, "__builtins__") == NULL) {

if (PyDict_SetItemString(d, "__builtins__",

PyEval_GetBuiltins()) != 0)

goto error;

}

/* Remember the filename as the __file__ attribute */

v = NULL;

if (pathname != NULL) {

v = PyString_FromString(pathname);

if (v == NULL)

PyErr_Clear();

}

if (v == NULL) {

v = ((PyCodeObject *)co)->co_filename;

Py_INCREF(v);

}

if (PyDict_SetItemString(d, "__file__", v) != 0)

PyErr_Clear(); /* Not important enough to report */

Py_DECREF(v);

v = PyEval_EvalCode((PyCodeObject *)co, d, d);

if (v == NULL)

goto error;

Py_DECREF(v);

if ((m = PyDict_GetItemString(modules, name)) == NULL) {

PyErr_Format(PyExc_ImportError,

"Loaded module %.200s not found in sys.modules",

name);

return NULL;

}

Py_INCREF(m);

return m;

error:

remove_module(name);

return NULL;

}

/* Given a pathname for a Python source file, fill a buffer with the

pathname for the corresponding compiled file. Return the pathname

for the compiled file, or NULL if there's no space in the buffer.

Doesn't set an exception. */

static char *

make_compiled_pathname(char *pathname, char *buf, size_t buflen)

{

size_t len = strlen(pathname);

if (len+2 > buflen)

return NULL;

#ifdef MS_WINDOWS

/* Treat .pyw as if it were .py. The case of ".pyw" must match

that used in _PyImport_StandardFiletab. */

if (len >= 4 && strcmp(&pathname[len-4], ".pyw") == 0)

--len; /* pretend 'w' isn't there */

#endif

memcpy(buf, pathname, len);

buf[len] = Py_OptimizeFlag ? 'o' : 'c';

buf[len+1] = '\0';

return buf;

}

/* Given a pathname for a Python source file, its time of last

modification, and a pathname for a compiled file, check whether the

compiled file represents the same version of the source. If so,

return a FILE pointer for the compiled file, positioned just after

the header; if not, return NULL.

Doesn't set an exception. */

static FILE *

check_compiled_module(char *pathname, time_t mtime, char *cpathname)

{

FILE *fp;

long magic;

long pyc_mtime;

fp = fopen(cpathname, "rb");

if (fp == NULL)

return NULL;

magic = PyMarshal_ReadLongFromFile(fp);

if (magic != pyc_magic) {

if (Py_VerboseFlag)

PySys_WriteStderr("# %s has bad magic\n", cpathname);

fclose(fp);

return NULL;

}

pyc_mtime = PyMarshal_ReadLongFromFile(fp);

if (pyc_mtime != mtime) {

if (Py_VerboseFlag)

PySys_WriteStderr("# %s has bad mtime\n", cpathname);

fclose(fp);

return NULL;

}

if (Py_VerboseFlag)

PySys_WriteStderr("# %s matches %s\n", cpathname, pathname);

return fp;

}

/* Read a code object from a file and check it for validity */

static PyCodeObject *

read_compiled_module(char *cpathname, FILE *fp)

{

PyObject *co;

co = PyMarshal_ReadLastObjectFromFile(fp);

if (co == NULL)

return NULL;

if (!PyCode_Check(co)) {

PyErr_Format(PyExc_ImportError,

"Non-code object in %.200s", cpathname);

Py_DECREF(co);

return NULL;

}

return (PyCodeObject *)co;

}

/* Load a module from a compiled file, execute it, and return its

module object WITH INCREMENTED REFERENCE COUNT */

static PyObject *

load_compiled_module(char *name, char *cpathname, FILE *fp)

{

long magic;

PyCodeObject *co;

PyObject *m;

magic = PyMarshal_ReadLongFromFile(fp);

if (magic != pyc_magic) {

PyErr_Format(PyExc_ImportError,

"Bad magic number in %.200s", cpathname);

return NULL;

}

(void) PyMarshal_ReadLongFromFile(fp);

co = read_compiled_module(cpathname, fp);

if (co == NULL)

return NULL;

if (Py_VerboseFlag)

PySys_WriteStderr("import %s # precompiled from %s\n",

name, cpathname);

m = PyImport_ExecCodeModuleEx(name, (PyObject *)co, cpathname);

Py_DECREF(co);

return m;

}

/* Parse a source file and return the corresponding code object */

static PyCodeObject *

parse_source_module(const char *pathname, FILE *fp)

{

PyCodeObject *co = NULL;

mod_ty mod;

PyCompilerFlags flags;

PyArena *arena = PyArena_New();

if (arena == NULL)

return NULL;

flags.cf_flags = 0;

mod = PyParser_ASTFromFile(fp, pathname, Py_file_input, 0, 0, &flags,

NULL, arena);

if (mod) {

co = PyAST_Compile(mod, pathname, NULL, arena);

}

PyArena_Free(arena);

return co;

}

/* Helper to open a bytecode file for writing in exclusive mode */

static FILE *

open_exclusive(char *filename, mode_t mode)

{

#if defined(O_EXCL)&&defined(O_CREAT)&&defined(O_WRONLY)&&defined(O_TRUNC)

/* Use O_EXCL to avoid a race condition when another process tries to

write the same file. When that happens, our open() call fails,

which is just fine (since it's only a cache).

XXX If the file exists and is writable but the directory is not

writable, the file will never be written. Oh well.

int fd;

(void) unlink(filename);

fd = open(filename, O_EXCL|O_CREAT|O_WRONLY|O_TRUNC

#ifdef O_BINARY

|O_BINARY /* necessary for Windows */

#endif

#ifdef __VMS

, mode, "ctxt=bin", "shr=nil"

#else

, mode

#endif

);

if (fd < 0)

return NULL;

return fdopen(fd, "wb");

#else

/* Best we can do -- on Windows this can't happen anyway */

return fopen(filename, "wb");

#endif

}

/* Write a compiled module to a file, placing the time of last

modification of its source into the header.

Errors are ignored, if a write error occurs an attempt is made to

remove the file. */

static void

write_compiled_module(PyCodeObject *co, char *cpathname, struct stat *srcstat, time_t mtime)

{

FILE *fp;

#ifdef MS_WINDOWS /* since Windows uses different permissions */

mode_t mode = srcstat->st_mode & ~S_IEXEC;

/* Issue #6074: We ensure user write access, so we can delete it later

* when the source file changes. (On POSIX, this only requires write

* access to the directory, on Windows, we need write access to the file

* as well)

mode |= _S_IWRITE;

#else

mode_t mode = srcstat->st_mode & ~S_IXUSR & ~S_IXGRP & ~S_IXOTH;

#endif

fp = open_exclusive(cpathname, mode);

if (fp == NULL) {

if (Py_VerboseFlag)

PySys_WriteStderr(

"# can't create %s\n", cpathname);

return;

}

PyMarshal_WriteLongToFile(pyc_magic, fp, Py_MARSHAL_VERSION);

/* First write a 0 for mtime */

PyMarshal_WriteLongToFile(0L, fp, Py_MARSHAL_VERSION);

PyMarshal_WriteObjectToFile((PyObject *)co, fp, Py_MARSHAL_VERSION);

if (fflush(fp) != 0 || ferror(fp)) {

if (Py_VerboseFlag)

PySys_WriteStderr("# can't write %s\n", cpathname);

/* Don't keep partial file */

fclose(fp);

(void) unlink(cpathname);

return;

}

/* Now write the true mtime (as a 32-bit field) */

fseek(fp, 4L, 0);

assert(mtime <= 0xFFFFFFFF);

PyMarshal_WriteLongToFile((long)mtime, fp, Py_MARSHAL_VERSION);

fflush(fp);

fclose(fp);

if (Py_VerboseFlag)

PySys_WriteStderr("# wrote %s\n", cpathname);

}

static void

update_code_filenames(PyCodeObject *co, PyObject *oldname, PyObject *newname)

{

PyObject *constants, *tmp;

Py_ssize_t i, n;

View remainder of file in raw view

cpython/Python/import.c at 2.7 · python-emscripten/cpython · GitHub

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