gh-64783: Fix signal.NSIG value on FreeBSD (#91929)

Fix signal.NSIG value on FreeBSD to accept signal numbers greater
than 32, like signal.SIGRTMIN and signal.SIGRTMAX.

* Add Py_NSIG constant.
* Add pycore_signal.h internal header file.
* _Py_Sigset_Converter() now includes the range of valid signals in
  the error message.

3 files changed, 27 insertions, 35 deletions

diff --git a/Modules/faulthandler.c b/Modules/faulthandler.c
index 91f9666..4f709ed 100644
--- a/Modules/faulthandler.c
+++ b/Modules/faulthandler.c
@@ -2,6 +2,7 @@
 #include "pycore_initconfig.h"    // _PyStatus_ERR
 #include "pycore_pyerrors.h"      // _Py_DumpExtensionModules
 #include "pycore_pystate.h"       // _PyThreadState_GET()
+#include "pycore_signal.h"        // Py_NSIG
 #include "pycore_traceback.h"     // _Py_DumpTracebackThreads
 
 #include "frameobject.h"
@@ -115,19 +116,6 @@ typedef struct {
 
 static user_signal_t *user_signals;
 
-/* the following macros come from Python: Modules/signalmodule.c */
-#ifndef NSIG
-# if defined(_NSIG)
-#  define NSIG _NSIG            /* For BSD/SysV */
-# elif defined(_SIGMAX)
-#  define NSIG (_SIGMAX + 1)    /* For QNX */
-# elif defined(SIGMAX)
-#  define NSIG (SIGMAX + 1)     /* For djgpp */
-# else
-#  define NSIG 64               /* Use a reasonable default value */
-# endif
-#endif
-
 static void faulthandler_user(int signum);
 #endif /* FAULTHANDLER_USER */
 
@@ -896,7 +884,7 @@ check_signum(int signum)
             return 0;
         }
     }
-    if (signum < 1 || NSIG <= signum) {
+    if (signum < 1 || Py_NSIG <= signum) {
         PyErr_SetString(PyExc_ValueError, "signal number out of range");
         return 0;
     }
@@ -935,7 +923,7 @@ faulthandler_register_py(PyObject *self,
         return NULL;
 
     if (user_signals == NULL) {
-        user_signals = PyMem_Calloc(NSIG, sizeof(user_signal_t));
+        user_signals = PyMem_Calloc(Py_NSIG, sizeof(user_signal_t));
         if (user_signals == NULL)
             return PyErr_NoMemory();
     }
@@ -1215,7 +1203,7 @@ faulthandler_traverse(PyObject *module, visitproc visit, void *arg)
     Py_VISIT(thread.file);
 #ifdef FAULTHANDLER_USER
     if (user_signals != NULL) {
-        for (size_t signum=0; signum < NSIG; signum++)
+        for (size_t signum=0; signum < Py_NSIG; signum++)
             Py_VISIT(user_signals[signum].file);
     }
 #endif
@@ -1416,7 +1404,7 @@ void _PyFaulthandler_Fini(void)
 #ifdef FAULTHANDLER_USER
     /* user */
     if (user_signals != NULL) {
-        for (size_t signum=0; signum < NSIG; signum++) {
+        for (size_t signum=0; signum < Py_NSIG; signum++) {
             faulthandler_unregister(&user_signals[signum], signum);
         }
         PyMem_Free(user_signals);
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
index a9132a7..a2ea507 100644
--- a/Modules/posixmodule.c
+++ b/Modules/posixmodule.c
@@ -29,6 +29,7 @@
 #include "pycore_moduleobject.h"  // _PyModule_GetState()
 #include "pycore_object.h"        // _PyObject_LookupSpecial()
 #include "pycore_pystate.h"       // _PyInterpreterState_GET()
+#include "pycore_signal.h"        // Py_NSIG
 
 #include "structmember.h"         // PyMemberDef
 #ifndef MS_WINDOWS
@@ -1503,10 +1504,11 @@ _Py_Sigset_Converter(PyObject *obj, void *addr)
     while ((item = PyIter_Next(iterator)) != NULL) {
         signum = PyLong_AsLongAndOverflow(item, &overflow);
         Py_DECREF(item);
-        if (signum <= 0 || signum >= NSIG) {
+        if (signum <= 0 || signum >= Py_NSIG) {
             if (overflow || signum != -1 || !PyErr_Occurred()) {
                 PyErr_Format(PyExc_ValueError,
-                             "signal number %ld out of range", signum);
+                             "signal number %ld out of range [1; %i]",
+                             signum, Py_NSIG - 1);
             }
             goto error;
         }
diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c
index 02c58ff..b602338 100644
--- a/Modules/signalmodule.c
+++ b/Modules/signalmodule.c
@@ -7,13 +7,13 @@
 #include "pycore_atomic.h"        // _Py_atomic_int
 #include "pycore_call.h"          // _PyObject_Call()
 #include "pycore_ceval.h"         // _PyEval_SignalReceived()
+#include "pycore_emscripten_signal.h"  // _Py_CHECK_EMSCRIPTEN_SIGNALS
 #include "pycore_fileutils.h"     // _Py_BEGIN_SUPPRESS_IPH
 #include "pycore_frame.h"         // _PyInterpreterFrame
 #include "pycore_moduleobject.h"  // _PyModule_GetState()
 #include "pycore_pyerrors.h"      // _PyErr_SetString()
-#include "pycore_pylifecycle.h"   // NSIG
 #include "pycore_pystate.h"       // _PyThreadState_GET()
-#include "pycore_emscripten_signal.h"  // _Py_CHECK_EMSCRIPTEN_SIGNALS
+#include "pycore_signal.h"        // Py_NSIG
 
 #ifndef MS_WINDOWS
 #  include "posixmodule.h"
@@ -106,7 +106,7 @@ static volatile struct {
      * (even though it would probably be otherwise, anyway).
      */
     _Py_atomic_address func;
-} Handlers[NSIG];
+} Handlers[Py_NSIG];
 
 #ifdef MS_WINDOWS
 #define INVALID_FD ((SOCKET_T)-1)
@@ -542,7 +542,7 @@ signal_signal_impl(PyObject *module, int signalnum, PyObject *handler)
                          "of the main interpreter");
         return NULL;
     }
-    if (signalnum < 1 || signalnum >= NSIG) {
+    if (signalnum < 1 || signalnum >= Py_NSIG) {
         _PyErr_SetString(tstate, PyExc_ValueError,
                          "signal number out of range");
         return NULL;
@@ -601,7 +601,7 @@ signal_getsignal_impl(PyObject *module, int signalnum)
 /*[clinic end generated code: output=35b3e0e796fd555e input=ac23a00f19dfa509]*/
 {
     PyObject *old_handler;
-    if (signalnum < 1 || signalnum >= NSIG) {
+    if (signalnum < 1 || signalnum >= Py_NSIG) {
         PyErr_SetString(PyExc_ValueError,
                         "signal number out of range");
         return NULL;
@@ -634,7 +634,7 @@ signal_strsignal_impl(PyObject *module, int signalnum)
 {
     const char *res;
 
-    if (signalnum < 1 || signalnum >= NSIG) {
+    if (signalnum < 1 || signalnum >= Py_NSIG) {
         PyErr_SetString(PyExc_ValueError,
                 "signal number out of range");
         return NULL;
@@ -712,7 +712,7 @@ static PyObject *
 signal_siginterrupt_impl(PyObject *module, int signalnum, int flag)
 /*[clinic end generated code: output=063816243d85dd19 input=4160acacca3e2099]*/
 {
-    if (signalnum < 1 || signalnum >= NSIG) {
+    if (signalnum < 1 || signalnum >= Py_NSIG) {
         PyErr_SetString(PyExc_ValueError,
                         "signal number out of range");
         return NULL;
@@ -964,7 +964,7 @@ sigset_to_set(sigset_t mask)
     if (result == NULL)
         return NULL;
 
-    for (sig = 1; sig < NSIG; sig++) {
+    for (sig = 1; sig < Py_NSIG; sig++) {
         if (sigismember(&mask, sig) != 1)
             continue;
 
@@ -1439,13 +1439,15 @@ the first is the signal number, the second is the interrupted stack frame.");
 static int
 signal_add_constants(PyObject *module)
 {
+    if (PyModule_AddIntConstant(module, "NSIG", Py_NSIG) < 0) {
+        return -1;
+    }
+
 #define ADD_INT_MACRO(macro) \
     if (PyModule_AddIntConstant(module, #macro, macro) < 0) { \
         return -1; \
     }
 
-    ADD_INT_MACRO(NSIG);
-
     // SIG_xxx pthread_sigmask() constants
 #ifdef SIG_BLOCK
     ADD_INT_MACRO(SIG_BLOCK);
@@ -1605,7 +1607,7 @@ static int
 signal_get_set_handlers(signal_state_t *state, PyObject *mod_dict)
 {
     // Get signal handlers
-    for (int signum = 1; signum < NSIG; signum++) {
+    for (int signum = 1; signum < Py_NSIG; signum++) {
         void (*c_handler)(int) = PyOS_getsig(signum);
         PyObject *func;
         if (c_handler == SIG_DFL) {
@@ -1762,7 +1764,7 @@ _PySignal_Fini(void)
     signal_state_t *state = &signal_global_state;
 
     // Restore default signals and clear handlers
-    for (int signum = 1; signum < NSIG; signum++) {
+    for (int signum = 1; signum < Py_NSIG; signum++) {
         PyObject *func = get_handler(signum);
         _Py_atomic_store_relaxed(&Handlers[signum].tripped, 0);
         set_handler(signum, NULL);
@@ -1828,7 +1830,7 @@ _PyErr_CheckSignalsTstate(PyThreadState *tstate)
 
     _PyInterpreterFrame *frame = tstate->cframe->current_frame;
     signal_state_t *state = &signal_global_state;
-    for (int i = 1; i < NSIG; i++) {
+    for (int i = 1; i < Py_NSIG; i++) {
         if (!_Py_atomic_load_relaxed(&Handlers[i].tripped)) {
             continue;
         }
@@ -1905,7 +1907,7 @@ _PyErr_CheckSignals(void)
 int
 PyErr_SetInterruptEx(int signum)
 {
-    if (signum < 1 || signum >= NSIG) {
+    if (signum < 1 || signum >= Py_NSIG) {
         return -1;
     }
 
@@ -1995,7 +1997,7 @@ _PySignal_Init(int install_signal_handlers)
     }
 #endif
 
-    for (int signum = 1; signum < NSIG; signum++) {
+    for (int signum = 1; signum < Py_NSIG; signum++) {
         _Py_atomic_store_relaxed(&Handlers[signum].tripped, 0);
     }
 
@@ -2045,7 +2047,7 @@ _clear_pending_signals(void)
     }
 
     _Py_atomic_store(&is_tripped, 0);
-    for (int i = 1; i < NSIG; ++i) {
+    for (int i = 1; i < Py_NSIG; ++i) {
         _Py_atomic_store_relaxed(&Handlers[i].tripped, 0);
     }
 }