From: Lennart Poettering <lennart@poettering.net>
Date: Tue, 27 Oct 2015 13:02:45 +0000 (+0100)
Subject: process-util: make some minor corrections to PID live detection
X-Git-Tag: v228.1~1^2~43
X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=4060a1603b2e82e6086a13456139f306736571e8

process-util: make some minor corrections to PID live detection
---

diff --git a/src/basic/process-util.c b/src/basic/process-util.c
index 8a1f54db8..5825944c9 100644
--- a/src/basic/process-util.c
+++ b/src/basic/process-util.c
@@ -556,9 +556,12 @@ int getenv_for_pid(pid_t pid, const char *field, char **_value) {
 bool pid_is_unwaited(pid_t pid) {
         /* Checks whether a PID is still valid at all, including a zombie */
 
-        if (pid <= 0)
+        if (pid < 0)
                 return false;
 
+        if (pid <= 1) /* If we or PID 1 would be dead and have been waited for, this code would not be running */
+                return true;
+
         if (kill(pid, 0) >= 0)
                 return true;
 
@@ -570,9 +573,12 @@ bool pid_is_alive(pid_t pid) {
 
         /* Checks whether a PID is still valid and not a zombie */
 
-        if (pid <= 0)
+        if (pid < 0)
                 return false;
 
+        if (pid <= 1) /* If we or PID 1 would be a zombie, this code would not be running */
+                return true;
+
         r = get_process_state(pid);
         if (r == -ESRCH || r == 'Z')
                 return false;