gh-137044: Support large limit values in getrlimit() and setrlimit()

serhiy-storchaka · serhiy-storchaka · commit 3ad0cf027114 · 2025-08-03T13:19:05.000+03:00
* Return large limit values as positive integers instead of negative integers
  in resource.getrlimit().
* Accept large values and reject negative values (except RLIM_INFINITY)
  for limits in resource.setrlimit().
diff --git a/Lib/test/test_resource.py b/Lib/test/test_resource.py
@@ -14,89 +14,133 @@ class ResourceTest(unittest.TestCase):
 
     def test_args(self):
         self.assertRaises(TypeError, resource.getrlimit)
-        self.assertRaises(TypeError, resource.getrlimit, 42, 42)
+        self.assertRaises(TypeError, resource.getrlimit, 0, 42)
+        self.assertRaises(OverflowError, resource.getrlimit, 2**1000)
+        self.assertRaises(OverflowError, resource.getrlimit, -2**1000)
+        self.assertRaises(TypeError, resource.getrlimit, '0')
         self.assertRaises(TypeError, resource.setrlimit)
-        self.assertRaises(TypeError, resource.setrlimit, 42, 42, 42)
+        self.assertRaises(TypeError, resource.setrlimit, 0)
+        self.assertRaises(TypeError, resource.setrlimit, 0, 42)
+        self.assertRaises(TypeError, resource.setrlimit, 0, 42, 42)
+        self.assertRaises(OverflowError, resource.setrlimit, 2**1000, (42, 42))
+        self.assertRaises(OverflowError, resource.setrlimit, -2**1000, (42, 42))
+        self.assertRaises(ValueError, resource.setrlimit, 0, (42,))
+        self.assertRaises(ValueError, resource.setrlimit, 0, (42, 42, 42))
+        self.assertRaises(TypeError, resource.setrlimit, '0', (42, 42))
+        self.assertRaises(TypeError, resource.setrlimit, 0, ('42', 42))
+        self.assertRaises(TypeError, resource.setrlimit, 0, (42, '42'))
 
     @unittest.skipIf(sys.platform == "vxworks",
                      "setting RLIMIT_FSIZE is not supported on VxWorks")
+    @unittest.skipUnless(hasattr(resource, 'RLIMIT_FSIZE'), 'requires resource.RLIMIT_FSIZE')
     def test_fsize_ismax(self):
-        try:
-            (cur, max) = resource.getrlimit(resource.RLIMIT_FSIZE)
-        except AttributeError:
-            pass
-        else:
-            # RLIMIT_FSIZE should be RLIM_INFINITY, which will be a really big
-            # number on a platform with large file support.  On these platforms,
-            # we need to test that the get/setrlimit functions properly convert
-            # the number to a C long long and that the conversion doesn't raise
-            # an error.
-            self.assertEqual(resource.RLIM_INFINITY, max)
-            resource.setrlimit(resource.RLIMIT_FSIZE, (cur, max))
+        (cur, max) = resource.getrlimit(resource.RLIMIT_FSIZE)
+        # RLIMIT_FSIZE should be RLIM_INFINITY, which will be a really big
+        # number on a platform with large file support.  On these platforms,
+        # we need to test that the get/setrlimit functions properly convert
+        # the number to a C long long and that the conversion doesn't raise
+        # an error.
+        self.assertEqual(resource.RLIM_INFINITY, max)
+        resource.setrlimit(resource.RLIMIT_FSIZE, (cur, max))
 
+    @unittest.skipIf(sys.platform == "vxworks",
+                     "setting RLIMIT_FSIZE is not supported on VxWorks")
+    @unittest.skipUnless(hasattr(resource, 'RLIMIT_FSIZE'), 'requires resource.RLIMIT_FSIZE')
     def test_fsize_enforced(self):
+        (cur, max) = resource.getrlimit(resource.RLIMIT_FSIZE)
+        # Check to see what happens when the RLIMIT_FSIZE is small.  Some
+        # versions of Python were terminated by an uncaught SIGXFSZ, but
+        # pythonrun.c has been fixed to ignore that exception.  If so, the
+        # write() should return EFBIG when the limit is exceeded.
+
+        # At least one platform has an unlimited RLIMIT_FSIZE and attempts
+        # to change it raise ValueError instead.
         try:
-            (cur, max) = resource.getrlimit(resource.RLIMIT_FSIZE)
-        except AttributeError:
-            pass
-        else:
-            # Check to see what happens when the RLIMIT_FSIZE is small.  Some
-            # versions of Python were terminated by an uncaught SIGXFSZ, but
-            # pythonrun.c has been fixed to ignore that exception.  If so, the
-            # write() should return EFBIG when the limit is exceeded.
-
-            # At least one platform has an unlimited RLIMIT_FSIZE and attempts
-            # to change it raise ValueError instead.
             try:
+                resource.setrlimit(resource.RLIMIT_FSIZE, (1024, max))
+                limit_set = True
+            except ValueError:
+                limit_set = False
+            f = open(os_helper.TESTFN, "wb")
+            try:
+                f.write(b"X" * 1024)
                 try:
-                    resource.setrlimit(resource.RLIMIT_FSIZE, (1024, max))
-                    limit_set = True
-                except ValueError:
-                    limit_set = False
-                f = open(os_helper.TESTFN, "wb")
-                try:
-                    f.write(b"X" * 1024)
-                    try:
-                        f.write(b"Y")
+                    f.write(b"Y")
+                    f.flush()
+                    # On some systems (e.g., Ubuntu on hppa) the flush()
+                    # doesn't always cause the exception, but the close()
+                    # does eventually.  Try flushing several times in
+                    # an attempt to ensure the file is really synced and
+                    # the exception raised.
+                    for i in range(5):
+                        time.sleep(.1)
                         f.flush()
-                        # On some systems (e.g., Ubuntu on hppa) the flush()
-                        # doesn't always cause the exception, but the close()
-                        # does eventually.  Try flushing several times in
-                        # an attempt to ensure the file is really synced and
-                        # the exception raised.
-                        for i in range(5):
-                            time.sleep(.1)
-                            f.flush()
-                    except OSError:
-                        if not limit_set:
-                            raise
-                    if limit_set:
-                        # Close will attempt to flush the byte we wrote
-                        # Restore limit first to avoid getting a spurious error
-                        resource.setrlimit(resource.RLIMIT_FSIZE, (cur, max))
-                finally:
-                    f.close()
-            finally:
+                except OSError:
+                    if not limit_set:
+                        raise
                 if limit_set:
+                    # Close will attempt to flush the byte we wrote
+                    # Restore limit first to avoid getting a spurious error
                     resource.setrlimit(resource.RLIMIT_FSIZE, (cur, max))
-                os_helper.unlink(os_helper.TESTFN)
+            finally:
+                f.close()
+        finally:
+            if limit_set:
+                resource.setrlimit(resource.RLIMIT_FSIZE, (cur, max))
+            os_helper.unlink(os_helper.TESTFN)
 
-    def test_fsize_toobig(self):
+    @unittest.skipIf(sys.platform == "vxworks",
+                     "setting RLIMIT_FSIZE is not supported on VxWorks")
+    @unittest.skipUnless(hasattr(resource, 'RLIMIT_FSIZE'), 'requires resource.RLIMIT_FSIZE')
+    def test_fsize_too_big(self):
         # Be sure that setrlimit is checking for really large values
         too_big = 10**50
+        (cur, max) = resource.getrlimit(resource.RLIMIT_FSIZE)
+        try:
+            resource.setrlimit(resource.RLIMIT_FSIZE, (too_big, max))
+        except (OverflowError, ValueError):
+            pass
         try:
-            (cur, max) = resource.getrlimit(resource.RLIMIT_FSIZE)
-        except AttributeError:
+            resource.setrlimit(resource.RLIMIT_FSIZE, (max, too_big))
+        except (OverflowError, ValueError):
+            pass
+
+    @unittest.skipIf(sys.platform == "vxworks",
+                     "setting RLIMIT_FSIZE is not supported on VxWorks")
+    @unittest.skipUnless(hasattr(resource, 'RLIMIT_FSIZE'), 'requires resource.RLIMIT_FSIZE')
+    def test_fsize_not_too_big(self):
+        (cur, max) = resource.getrlimit(resource.RLIMIT_FSIZE)
+        self.addCleanup(resource.setrlimit, resource.RLIMIT_FSIZE, (cur, max))
+
+        resource.setrlimit(resource.RLIMIT_FSIZE, (2**31-1, max))
+        self.assertEqual(resource.getrlimit(resource.RLIMIT_FSIZE), (2**31-1, max))
+        resource.setrlimit(resource.RLIMIT_FSIZE, (2**31, max))
+        self.assertEqual(resource.getrlimit(resource.RLIMIT_FSIZE), (2**31, max))
+        resource.setrlimit(resource.RLIMIT_FSIZE, (2**32-2, max))
+        self.assertEqual(resource.getrlimit(resource.RLIMIT_FSIZE), (2**32-2, max))
+
+        try:
+            resource.setrlimit(resource.RLIMIT_FSIZE, (2**32, max))
+        except OverflowError:
             pass
         else:
-            try:
-                resource.setrlimit(resource.RLIMIT_FSIZE, (too_big, max))
-            except (OverflowError, ValueError):
-                pass
-            try:
-                resource.setrlimit(resource.RLIMIT_FSIZE, (max, too_big))
-            except (OverflowError, ValueError):
-                pass
+            self.assertEqual(resource.getrlimit(resource.RLIMIT_FSIZE), (2**32, max))
+            resource.setrlimit(resource.RLIMIT_FSIZE, (2**63-1, max))
+            self.assertEqual(resource.getrlimit(resource.RLIMIT_FSIZE), (2**63-1, max))
+            resource.setrlimit(resource.RLIMIT_FSIZE, (2**63, max))
+            self.assertEqual(resource.getrlimit(resource.RLIMIT_FSIZE), (2**63, max))
+            resource.setrlimit(resource.RLIMIT_FSIZE, (2**64-2, max))
+            self.assertEqual(resource.getrlimit(resource.RLIMIT_FSIZE), (2**64-2, max))
+
+    @unittest.skipIf(sys.platform == "vxworks",
+                     "setting RLIMIT_FSIZE is not supported on VxWorks")
+    @unittest.skipUnless(hasattr(resource, 'RLIMIT_FSIZE'), 'requires resource.RLIMIT_FSIZE')
+    def test_fsize_negative(self):
+        (cur, max) = resource.getrlimit(resource.RLIMIT_FSIZE)
+        for value in -2, -2**31, -2**32-1, -2**63, -2**64-1, -2**1000:
+            with self.subTest(value=value):
+                self.assertRaises(ValueError, resource.setrlimit, resource.RLIMIT_FSIZE, (value, max))
+                self.assertRaises(ValueError, resource.setrlimit, resource.RLIMIT_FSIZE, (cur, value))
 
     @unittest.skipUnless(hasattr(resource, "getrusage"), "needs getrusage")
     def test_getrusage(self):
@@ -117,21 +161,18 @@ def test_getrusage(self):
     # Issue 6083: Reference counting bug
     @unittest.skipIf(sys.platform == "vxworks",
                      "setting RLIMIT_CPU is not supported on VxWorks")
+    @unittest.skipUnless(hasattr(resource, 'RLIMIT_CPU'), 'requires resource.RLIMIT_CPU')
     def test_setrusage_refcount(self):
-        try:
-            limits = resource.getrlimit(resource.RLIMIT_CPU)
-        except AttributeError:
-            pass
-        else:
-            class BadSequence:
-                def __len__(self):
-                    return 2
-                def __getitem__(self, key):
-                    if key in (0, 1):
-                        return len(tuple(range(1000000)))
-                    raise IndexError
+        limits = resource.getrlimit(resource.RLIMIT_CPU)
+        class BadSequence:
+            def __len__(self):
+                return 2
+            def __getitem__(self, key):
+                if key in (0, 1):
+                    return len(tuple(range(1000000)))
+                raise IndexError
 
-            resource.setrlimit(resource.RLIMIT_CPU, BadSequence())
+        resource.setrlimit(resource.RLIMIT_CPU, BadSequence())
 
     def test_pagesize(self):
         pagesize = resource.getpagesize()
@@ -168,7 +209,8 @@ class BadSeq:
             def __len__(self):
                 return 2
             def __getitem__(self, key):
-                return limits[key] - 1  # new reference
+                lim = limits[key]
+                return lim - 1 if lim > 0 else lim + 0xFFFF_FFFF  # new reference
 
         limits = resource.getrlimit(resource.RLIMIT_AS)
         self.assertEqual(resource.prlimit(0, resource.RLIMIT_AS, BadSeq()),
diff --git a/Misc/NEWS.d/next/Library/2025-08-03-13-16-39.gh-issue-137044.0hPVL_.rst b/Misc/NEWS.d/next/Library/2025-08-03-13-16-39.gh-issue-137044.0hPVL_.rst
@@ -0,0 +1,4 @@
+Return large limit values as positive integers instead of negative integers
+in :func:`resource.getrlimit`. Accept large values and reject negative
+values (except :data:`~resource.RLIM_INFINITY`) for limits in
+:func:`resource.setrlimit`.
diff --git a/Modules/resource.c b/Modules/resource.c
@@ -1,9 +1,3 @@
-// Need limited C API version 3.13 for PySys_Audit()
-#include "pyconfig.h"   // Py_GIL_DISABLED
-#ifndef Py_GIL_DISABLED
-#  define Py_LIMITED_API 0x030d0000
-#endif
-
 #include "Python.h"
 #include <errno.h>                // errno
 #include <string.h>
@@ -150,6 +144,35 @@ resource_getrusage_impl(PyObject *module, int who)
 }
 #endif
 
+static int
+py2rlim(PyObject *obj, rlim_t *out)
+{
+    obj = PyNumber_Index(obj);
+    if (obj == NULL) {
+        return -1;
+    }
+    int neg = PyLong_IsNegative(obj);
+    assert(neg >= 0);
+    Py_ssize_t bytes = PyLong_AsNativeBytes(obj, out, sizeof(*out),
+                                            Py_ASNATIVEBYTES_NATIVE_ENDIAN |
+                                            Py_ASNATIVEBYTES_UNSIGNED_BUFFER);
+    Py_DECREF(obj);
+    if (bytes < 0) {
+        return -1;
+    }
+    else if (neg && (*out != RLIM_INFINITY || bytes > (Py_ssize_t)sizeof(*out))) {
+        PyErr_SetString(PyExc_ValueError,
+            "Cannot convert negative int");
+        return -1;
+    }
+    else if (bytes > (Py_ssize_t)sizeof(*out)) {
+        PyErr_SetString(PyExc_OverflowError,
+            "Python int too large to convert to C rlim_t");
+        return -1;
+    }
+    return 0;
+}
+
 static int
 py2rlimit(PyObject *limits, struct rlimit *rl_out)
 {
@@ -166,42 +189,38 @@ py2rlimit(PyObject *limits, struct rlimit *rl_out)
     }
     curobj = PyTuple_GetItem(limits, 0);  // borrowed
     maxobj = PyTuple_GetItem(limits, 1);  // borrowed
-#if !defined(HAVE_LARGEFILE_SUPPORT)
-    rl_out->rlim_cur = PyLong_AsLong(curobj);
-    if (rl_out->rlim_cur == (rlim_t)-1 && PyErr_Occurred())
-        goto error;
-    rl_out->rlim_max = PyLong_AsLong(maxobj);
-    if (rl_out->rlim_max == (rlim_t)-1 && PyErr_Occurred())
-        goto error;
-#else
-    /* The limits are probably bigger than a long */
-    rl_out->rlim_cur = PyLong_AsLongLong(curobj);
-    if (rl_out->rlim_cur == (rlim_t)-1 && PyErr_Occurred())
-        goto error;
-    rl_out->rlim_max = PyLong_AsLongLong(maxobj);
-    if (rl_out->rlim_max == (rlim_t)-1 && PyErr_Occurred())
+    if (py2rlim(curobj, &rl_out->rlim_cur) < 0 ||
+        py2rlim(maxobj, &rl_out->rlim_max) < 0)
+    {
         goto error;
-#endif
+    }
 
     Py_DECREF(limits);
-    rl_out->rlim_cur = rl_out->rlim_cur & RLIM_INFINITY;
-    rl_out->rlim_max = rl_out->rlim_max & RLIM_INFINITY;
     return 0;
 
 error:
     Py_DECREF(limits);
     return -1;
 }
 
+static PyObject*
+rlim2py(rlim_t value)
+{
+    if (value == RLIM_INFINITY) {
+        return PyLong_FromNativeBytes(&value, sizeof(value), -1);
+    }
+    return PyLong_FromUnsignedNativeBytes(&value, sizeof(value), -1);
+}
+
 static PyObject*
 rlimit2py(struct rlimit rl)
 {
-    if (sizeof(rl.rlim_cur) > sizeof(long)) {
-        return Py_BuildValue("LL",
-                             (long long) rl.rlim_cur,
-                             (long long) rl.rlim_max);
+    PyObject *cur = rlim2py(rl.rlim_cur);
+    if (cur == NULL) {
+        return NULL;
     }
-    return Py_BuildValue("ll", (long) rl.rlim_cur, (long) rl.rlim_max);
+    PyObject *max = rlim2py(rl.rlim_max);
+    return Py_BuildValue("NN", cur, max);
 }
 
 /*[clinic input]
@@ -495,14 +514,7 @@ resource_exec(PyObject *module)
     ADD_INT(module, RLIMIT_KQUEUES);
 #endif
 
-    PyObject *v;
-    if (sizeof(RLIM_INFINITY) > sizeof(long)) {
-        v = PyLong_FromLongLong((long long) RLIM_INFINITY);
-    } else
-    {
-        v = PyLong_FromLong((long) RLIM_INFINITY);
-    }
-    if (PyModule_Add(module, "RLIM_INFINITY", v) < 0) {
+    if (PyModule_Add(module, "RLIM_INFINITY", rlim2py(RLIM_INFINITY)) < 0) {
         return -1;
     }
     return 0;
