Instead of recording the Unix time in a process when it starts, record the

uptime.  Where necessary, convert it back to Unix time by adding boottime
to it.  This fixes a potential problem in the accounting code, which would
compute the elapsed time incorrectly if the Unix time was stepped during
the lifetime of the process.

5 files changed, 8 insertions, 7 deletions

diff --git a/sys/kern/init_main.c b/sys/kern/init_main.c
index d0cfa52..83fca78 100644
--- a/sys/kern/init_main.c
+++ b/sys/kern/init_main.c
@@ -467,7 +467,7 @@ proc0_post(void *dummy __unused)
 	 */
 	sx_slock(&allproc_lock);
 	LIST_FOREACH(p, &allproc, p_list) {
-		microtime(&p->p_stats->p_start);
+		microuptime(&p->p_stats->p_start);
 		p->p_runtime.sec = 0;
 		p->p_runtime.frac = 0;
 	}
diff --git a/sys/kern/kern_acct.c b/sys/kern/kern_acct.c
index 9de4641..19e5b1c 100644
--- a/sys/kern/kern_acct.c
+++ b/sys/kern/kern_acct.c
@@ -250,8 +250,10 @@ acct_process(td)
 	acct.ac_stime = encode_comp_t(st.tv_sec, st.tv_usec);
 
 	/* (3) The elapsed time the command ran (and its starting time) */
-	acct.ac_btime = p->p_stats->p_start.tv_sec;
-	microtime(&tmp);
+	tmp = boottime;
+	timevaladd(&tmp, &p->p_stats->p_start);
+	acct.ac_btime = tmp.tv_sec;
+	microuptime(&tmp);
 	timevalsub(&tmp, &p->p_stats->p_start);
 	acct.ac_etime = encode_comp_t(tmp.tv_sec, tmp.tv_usec);
 
diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index 1cc9580..7d2c65c 100644
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -686,7 +686,7 @@ again:
 	 * If RFSTOPPED not requested, make child runnable and add to
 	 * run queue.
 	 */
-	microtime(&(p2->p_stats->p_start));
+	microuptime(&p2->p_stats->p_start);
 	if ((flags & RFSTOPPED) == 0) {
 		mtx_lock_spin(&sched_lock);
 		p2->p_state = PRS_NORMAL;
diff --git a/sys/kern/kern_kthread.c b/sys/kern/kern_kthread.c
index 46fa97c..d4846dd 100644
--- a/sys/kern/kern_kthread.c
+++ b/sys/kern/kern_kthread.c
@@ -79,7 +79,7 @@ kthread_create(void (*func)(void *), void *arg,
 	struct thread *td;
 	struct proc *p2;
 
-	if (!proc0.p_stats /* || proc0.p_stats->p_start.tv_sec == 0 */)
+	if (!proc0.p_stats)
 		panic("kthread_create called too soon");
 
 	error = fork1(&thread0, RFMEM | RFFDG | RFPROC | RFSTOPPED | flags,
diff --git a/sys/kern/kern_proc.c b/sys/kern/kern_proc.c
index 111c0f2..5ad7882 100644
--- a/sys/kern/kern_proc.c
+++ b/sys/kern/kern_proc.c
@@ -677,8 +677,7 @@ fill_kinfo_proc(p, kp)
 	}
 	if ((p->p_sflag & PS_INMEM) && p->p_stats) {
 		kp->ki_start = p->p_stats->p_start;
-		if (kp->ki_start.tv_sec < 3600)
-			kp->ki_start.tv_sec += boottime.tv_sec;
+		timevaladd(&kp->ki_start, &boottime);
 		kp->ki_rusage = p->p_stats->p_ru;
 		kp->ki_childtime.tv_sec = p->p_stats->p_cru.ru_utime.tv_sec +
 		    p->p_stats->p_cru.ru_stime.tv_sec;