From: Lennart Poettering <lennart@poettering.net>
Date: Mon, 13 Jan 2025 10:06:27 +0000 (+0100)
Subject: pidref: various shortcuts to pidref_equal()
X-Git-Tag: v258-rc1~1580^2~4
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8110b34b64bfdda0a82b04544a7be07b7f0a5c7a;p=thirdparty%2Fsystemd.git

pidref: various shortcuts to pidref_equal()

This adds some shortcuts to pidref_equal(), so that we don't have to
query the pidfs id if there's no need.
---

diff --git a/src/basic/pidref.c b/src/basic/pidref.c
index a275f77b569..ccfa2903b60 100644
--- a/src/basic/pidref.c
+++ b/src/basic/pidref.c
@@ -40,6 +40,10 @@ int pidref_acquire_pidfd_id(PidRef *pidref) {
 
 bool pidref_equal(PidRef *a, PidRef *b) {
 
+        /* If this is the very same structure, it definitely refers to the same process */
+        if (a == b)
+                return true;
+
         if (!pidref_is_set(a))
                 return !pidref_is_set(b);
 
@@ -58,9 +62,15 @@ bool pidref_equal(PidRef *a, PidRef *b) {
                 if (a->fd_id == 0 || b->fd_id == 0)
                         return true;
         } else {
+                /* If the other side is remote, then this is not the same */
                 if (pidref_is_remote(b))
                         return false;
 
+                /* PID1 cannot exit, hence it cannot change pidfs ids, hence no point in comparing them, we
+                 * can shortcut things */
+                if (a->pid == 1)
+                        return true;
+
                 /* Try to compare pidfds using their inode numbers. This way we can ensure that we
                  * don't spuriously consider two PidRefs equal if the pid has been reused once. Note
                  * that we ignore all errors here, not only EOPNOTSUPP, as fstat() might fail due to