signal: add strsignal() (#6017)

Co-authored-by: Vajrasky Kok <sky.kok@speaklikeaking.com>

2 files changed, 92 insertions, 1 deletions

diff --git a/Modules/clinic/signalmodule.c.h b/Modules/clinic/signalmodule.c.h
index dc3aadf..1c43971 100644
--- a/Modules/clinic/signalmodule.c.h
+++ b/Modules/clinic/signalmodule.c.h
@@ -129,6 +129,36 @@ exit:
     return return_value;
 }
 
+PyDoc_STRVAR(signal_strsignal__doc__,
+"strsignal($module, signalnum, /)\n"
+"--\n"
+"\n"
+"Return the system description of the given signal.\n"
+"\n"
+"The return values can be such as \"Interrupt\", \"Segmentation fault\", etc.\n"
+"Returns None if the signal is not recognized.");
+
+#define SIGNAL_STRSIGNAL_METHODDEF    \
+    {"strsignal", (PyCFunction)signal_strsignal, METH_O, signal_strsignal__doc__},
+
+static PyObject *
+signal_strsignal_impl(PyObject *module, int signalnum);
+
+static PyObject *
+signal_strsignal(PyObject *module, PyObject *arg)
+{
+    PyObject *return_value = NULL;
+    int signalnum;
+
+    if (!PyArg_Parse(arg, "i:strsignal", &signalnum)) {
+        goto exit;
+    }
+    return_value = signal_strsignal_impl(module, signalnum);
+
+exit:
+    return return_value;
+}
+
 #if defined(HAVE_SIGINTERRUPT)
 
 PyDoc_STRVAR(signal_siginterrupt__doc__,
@@ -440,4 +470,4 @@ exit:
 #ifndef SIGNAL_PTHREAD_KILL_METHODDEF
     #define SIGNAL_PTHREAD_KILL_METHODDEF
 #endif /* !defined(SIGNAL_PTHREAD_KILL_METHODDEF) */
-/*[clinic end generated code: output=36132f4189381fe0 input=a9049054013a1b77]*/
+/*[clinic end generated code: output=7b41486acf93aa8e input=a9049054013a1b77]*/
diff --git a/Modules/signalmodule.c b/Modules/signalmodule.c
index b553eed..7916160 100644
--- a/Modules/signalmodule.c
+++ b/Modules/signalmodule.c
@@ -504,6 +504,66 @@ signal_getsignal_impl(PyObject *module, int signalnum)
     }
 }
 
+
+/*[clinic input]
+signal.strsignal
+
+    signalnum: int
+    /
+
+Return the system description of the given signal.
+
+The return values can be such as "Interrupt", "Segmentation fault", etc.
+Returns None if the signal is not recognized.
+[clinic start generated code]*/
+
+static PyObject *
+signal_strsignal_impl(PyObject *module, int signalnum)
+/*[clinic end generated code: output=44e12e1e3b666261 input=b77914b03f856c74]*/
+{
+    char *res;
+
+    if (signalnum < 1 || signalnum >= NSIG) {
+        PyErr_SetString(PyExc_ValueError,
+                "signal number out of range");
+        return NULL;
+    }
+
+#ifdef MS_WINDOWS
+    /* Custom redefinition of POSIX signals allowed on Windows */
+    switch (signalnum) {
+        case SIGINT:
+            res = "Interrupt";
+            break;
+        case SIGILL:
+            res = "Illegal instruction";
+            break;
+        case SIGABRT:
+            res = "Aborted";
+            break;
+        case SIGFPE:
+            res = "Floating point exception";
+            break;
+        case SIGSEGV:
+            res = "Segmentation fault";
+            break;
+        case SIGTERM:
+            res = "Terminated";
+            break;
+        default:
+            Py_RETURN_NONE;
+    }
+#else
+    errno = 0;
+    res = strsignal(signalnum);
+
+    if (errno || res == NULL || strstr(res, "Unknown signal") != NULL)
+        Py_RETURN_NONE;
+#endif
+
+    return Py_BuildValue("s", res);
+}
+
 #ifdef HAVE_SIGINTERRUPT
 
 /*[clinic input]
@@ -1152,6 +1212,7 @@ static PyMethodDef signal_methods[] = {
     SIGNAL_SETITIMER_METHODDEF
     SIGNAL_GETITIMER_METHODDEF
     SIGNAL_SIGNAL_METHODDEF
+    SIGNAL_STRSIGNAL_METHODDEF
     SIGNAL_GETSIGNAL_METHODDEF
     {"set_wakeup_fd", (PyCFunction)signal_set_wakeup_fd, METH_VARARGS | METH_KEYWORDS, set_wakeup_fd_doc},
     SIGNAL_SIGINTERRUPT_METHODDEF