Author: kib
Date: Fri Nov 16 08:25:06 2012
New Revision: 243142
URL: http://svnweb.freebsd.org/changeset/base/243142
Log:
In pget(9), if PGET_NOTWEXIT flag is not specified, also search the
zombie list for the pid. This allows several kern.proc sysctls to
report useful information for zombies.
Hold the allproc_lock around all searches instead of relocking it.
Remove private pfind_locked() from the new nfs client code.
Requested and reviewed by: pjd
Tested by: pho
MFC after: 3 weeks
Modified:
head/sys/fs/nfsclient/nfs_clport.c
head/sys/kern/kern_proc.c
head/sys/sys/proc.h
Modified: head/sys/fs/nfsclient/nfs_clport.c
==============================================================================
--- head/sys/fs/nfsclient/nfs_clport.c Fri Nov 16 07:30:38 2012
(r243141)
+++ head/sys/fs/nfsclient/nfs_clport.c Fri Nov 16 08:25:06 2012
(r243142)
@@ -1150,31 +1150,6 @@ nfscl_maperr(struct thread *td, int erro
}
/*
- * Locate a process by number; return only "live" processes -- i.e., neither
- * zombies nor newly born but incompletely initialized processes. By not
- * returning processes in the PRS_NEW state, we allow callers to avoid
- * testing for that condition to avoid dereferencing p_ucred, et al.
- * Identical to pfind() in kern_proc.c, except it assume the list is
- * already locked.
- */
-static struct proc *
-pfind_locked(pid_t pid)
-{
- struct proc *p;
-
- LIST_FOREACH(p, PIDHASH(pid), p_hash)
- if (p->p_pid == pid) {
- PROC_LOCK(p);
- if (p->p_state == PRS_NEW) {
- PROC_UNLOCK(p);
- p = NULL;
- }
- break;
- }
- return (p);
-}
-
-/*
* Check to see if the process for this owner exists. Return 1 if it doesn't
* and 0 otherwise.
*/
Modified: head/sys/kern/kern_proc.c
==============================================================================
--- head/sys/kern/kern_proc.c Fri Nov 16 07:30:38 2012 (r243141)
+++ head/sys/kern/kern_proc.c Fri Nov 16 08:25:06 2012 (r243142)
@@ -137,6 +137,7 @@ static void proc_dtor(void *mem, int siz
static int proc_init(void *mem, int size, int flags);
static void proc_fini(void *mem, int size);
static void pargs_free(struct pargs *pa);
+static struct proc *zpfind_locked(pid_t pid);
/*
* Other process lists
@@ -284,20 +285,13 @@ inferior(p)
return (1);
}
-/*
- * Locate a process by number; return only "live" processes -- i.e., neither
- * zombies nor newly born but incompletely initialized processes. By not
- * returning processes in the PRS_NEW state, we allow callers to avoid
- * testing for that condition to avoid dereferencing p_ucred, et al.
- */
struct proc *
-pfind(pid)
- register pid_t pid;
+pfind_locked(pid_t pid)
{
- register struct proc *p;
+ struct proc *p;
- sx_slock(&allproc_lock);
- LIST_FOREACH(p, PIDHASH(pid), p_hash)
+ sx_assert(&allproc_lock, SX_LOCKED);
+ LIST_FOREACH(p, PIDHASH(pid), p_hash) {
if (p->p_pid == pid) {
PROC_LOCK(p);
if (p->p_state == PRS_NEW) {
@@ -306,17 +300,34 @@ pfind(pid)
}
break;
}
+ }
+ return (p);
+}
+
+/*
+ * Locate a process by number; return only "live" processes -- i.e., neither
+ * zombies nor newly born but incompletely initialized processes. By not
+ * returning processes in the PRS_NEW state, we allow callers to avoid
+ * testing for that condition to avoid dereferencing p_ucred, et al.
+ */
+struct proc *
+pfind(pid_t pid)
+{
+ struct proc *p;
+
+ sx_slock(&allproc_lock);
+ p = pfind_locked(pid);
sx_sunlock(&allproc_lock);
return (p);
}
static struct proc *
-pfind_tid(pid_t tid)
+pfind_tid_locked(pid_t tid)
{
struct proc *p;
struct thread *td;
- sx_slock(&allproc_lock);
+ sx_assert(&allproc_lock, SX_LOCKED);
FOREACH_PROC_IN_SYSTEM(p) {
PROC_LOCK(p);
if (p->p_state == PRS_NEW) {
@@ -330,7 +341,6 @@ pfind_tid(pid_t tid)
PROC_UNLOCK(p);
}
found:
- sx_sunlock(&allproc_lock);
return (p);
}
@@ -364,12 +374,16 @@ pget(pid_t pid, int flags, struct proc *
struct proc *p;
int error;
+ sx_slock(&allproc_lock);
if (pid <= PID_MAX)
- p = pfind(pid);
+ p = pfind_locked(pid);
else if ((flags & PGET_NOTID) == 0)
- p = pfind_tid(pid);
+ p = pfind_tid_locked(pid);
else
p = NULL;
+ if (p == NULL && (flags & PGET_NOTWEXIT) == 0)
+ p = zpfind_locked(pid);
+ sx_sunlock(&allproc_lock);
if (p == NULL)
return (ESRCH);
if ((flags & PGET_CANSEE) != 0) {
@@ -1044,6 +1058,21 @@ pstats_free(struct pstats *ps)
free(ps, M_SUBPROC);
}
+static struct proc *
+zpfind_locked(pid_t pid)
+{
+ struct proc *p;
+
+ sx_assert(&allproc_lock, SX_LOCKED);
+ LIST_FOREACH(p, &zombproc, p_list) {
+ if (p->p_pid == pid) {
+ PROC_LOCK(p);
+ break;
+ }
+ }
+ return (p);
+}
+
/*
* Locate a zombie process by number
*/
@@ -1053,11 +1082,7 @@ zpfind(pid_t pid)
struct proc *p;
sx_slock(&allproc_lock);
- LIST_FOREACH(p, &zombproc, p_list)
- if (p->p_pid == pid) {
- PROC_LOCK(p);
- break;
- }
+ p = zpfind_locked(pid);
sx_sunlock(&allproc_lock);
return (p);
}
Modified: head/sys/sys/proc.h
==============================================================================
--- head/sys/sys/proc.h Fri Nov 16 07:30:38 2012 (r243141)
+++ head/sys/sys/proc.h Fri Nov 16 08:25:06 2012 (r243142)
@@ -835,6 +835,7 @@ extern struct proc *initproc, *pageproc;
extern struct uma_zone *proc_zone;
struct proc *pfind(pid_t); /* Find process by id. */
+struct proc *pfind_locked(pid_t pid);
struct pgrp *pgfind(pid_t); /* Find process group by id. */
struct proc *zpfind(pid_t); /* Find zombie process by id. */
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