GH-93312: Add os.PIDFD_NONBLOCK flag (#93313)

kumaraditya303 · web-flow · commit a565ab0fd58b · 2022-05-31T12:51:29.000+02:00
diff --git a/Doc/library/os.rst b/Doc/library/os.rst
@@ -3897,16 +3897,25 @@ written in Python, such as a mail server's external command delivery program.
 
 .. function:: pidfd_open(pid, flags=0)
 
-   Return a file descriptor referring to the process *pid*.  This descriptor can
-   be used to perform process management without races and signals.  The *flags*
-   argument is provided for future extensions; no flag values are currently
-   defined.
+   Return a file descriptor referring to the process *pid* with *flags* set.
+   This descriptor can be used to perform process management without races
+   and signals.
 
    See the :manpage:`pidfd_open(2)` man page for more details.
 
    .. availability:: Linux 5.3+
    .. versionadded:: 3.9
 
+   .. data:: PIDFD_NONBLOCK
+
+      This flag indicates that the file descriptor will be non-blocking.
+      If the process referred to by the file descriptor has not yet terminated,
+      then an attempt to wait on the file descriptor using :manpage:`waitid(2)`
+      will immediately return the error :data:`~errno.EAGAIN` rather than blocking.
+
+   .. availability:: Linux 5.10+
+   .. versionadded:: 3.12
+
 
 .. function:: plock(op)
 
diff --git a/Doc/whatsnew/3.12.rst b/Doc/whatsnew/3.12.rst
@@ -90,6 +90,13 @@ New Modules
 Improved Modules
 ================
 
+os
+--
+
+* Add :data:`os.PIDFD_NONBLOCK` to open a file descriptor
+  for a process with :func:`os.pidfd_open` in non-blocking mode.
+  (Contributed by Kumar Aditya in :gh:`93312`.)
+
 
 Optimizations
 =============
diff --git a/Misc/NEWS.d/next/Library/2022-05-28-08-02-55.gh-issue-93312.HY0Uzj.rst b/Misc/NEWS.d/next/Library/2022-05-28-08-02-55.gh-issue-93312.HY0Uzj.rst
@@ -0,0 +1,3 @@
+Add :data:`os.PIDFD_NONBLOCK` flag to open a file descriptor
+for a process with :func:`os.pidfd_open` in non-blocking mode.
+Patch by Kumar Aditya.
diff --git a/Modules/posixmodule.c b/Modules/posixmodule.c
@@ -15255,6 +15255,9 @@ all_ins(PyObject *m)
 #ifdef P_PIDFD
     if (PyModule_AddIntMacro(m, P_PIDFD)) return -1;
 #endif
+#ifdef PIDFD_NONBLOCK
+    if (PyModule_AddIntMacro(m, PIDFD_NONBLOCK)) return -1;
+#endif
 #endif
 #ifdef WEXITED
     if (PyModule_AddIntMacro(m, WEXITED)) return -1;

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,3 @@`
	`1`	+Add :data:`os.PIDFD_NONBLOCK` flag to open a file descriptor
	`2`	+for a process with :func:`os.pidfd_open` in non-blocking mode.
	`3`	`+Patch by Kumar Aditya.`