Subject: [PATCH 4/6] Use pid_to_nr() in process info functions
From: Sukadev Bhattiprolu <[EMAIL PROTECTED]>
Use pid_to_nr() function in getppid(), getpgid() and getsid() functions
so they return the correct pid_t for processes in multiple pid namespaces.
Note: We don't need pid_to_nr() in getpid() because the process always
"sees itself" as being in its active pid namespace. Using pid_to_nr()
in getpid() would unnecessarily hurt its performance.
Signed-off-by: Sukadev Bhattiprolu <[EMAIL PROTECTED]>
---
include/linux/sched.h | 24 ++++++++++++++++++++++++
kernel/sys.c | 10 +++++-----
kernel/timer.c | 2 +-
3 files changed, 30 insertions(+), 6 deletions(-)
Index: lx26-22-rc6-mm1/include/linux/sched.h
===================================================================
--- lx26-22-rc6-mm1.orig/include/linux/sched.h 2007-07-05 18:53:42.000000000
-0700
+++ lx26-22-rc6-mm1/include/linux/sched.h 2007-07-05 18:57:34.000000000
-0700
@@ -1200,6 +1200,30 @@ static inline struct pid *task_tgid(stru
return task->group_leader->pids[PIDTYPE_PID].pid;
}
+/* NOTE: Caller must hold rcu_readlock() */
+static inline struct pid *task_parent_tgid(struct task_struct *task)
+{
+ return task_tgid(rcu_dereference(task->real_parent));
+}
+
+/* NOTE: Caller must hold rcu_readlock() */
+static inline struct pid *task_parent_pid(struct task_struct *task)
+{
+ return task_pid(rcu_dereference(task->real_parent));
+}
+
+/* NOTE: Caller must hold rcu_readlock() */
+static inline struct pid *task_tracer_tgid(struct task_struct *task)
+{
+ return task_tgid(rcu_dereference(task->parent));
+}
+
+/* NOTE: Caller must hold rcu_readlock() */
+static inline struct pid *task_tracer_pid(struct task_struct *task)
+{
+ return task_pid(rcu_dereference(task->parent));
+}
+
static inline struct pid *task_pgrp(struct task_struct *task)
{
return task->group_leader->pids[PIDTYPE_PGID].pid;
Index: lx26-22-rc6-mm1/kernel/timer.c
===================================================================
--- lx26-22-rc6-mm1.orig/kernel/timer.c 2007-07-05 18:53:42.000000000 -0700
+++ lx26-22-rc6-mm1/kernel/timer.c 2007-07-05 18:57:34.000000000 -0700
@@ -971,7 +971,7 @@ asmlinkage long sys_getppid(void)
int pid;
rcu_read_lock();
- pid = rcu_dereference(current->real_parent)->tgid;
+ pid = pid_to_nr(task_parent_tgid(current));
rcu_read_unlock();
return pid;
Index: lx26-22-rc6-mm1/kernel/sys.c
===================================================================
--- lx26-22-rc6-mm1.orig/kernel/sys.c 2007-07-05 18:53:42.000000000 -0700
+++ lx26-22-rc6-mm1/kernel/sys.c 2007-07-05 18:57:34.000000000 -0700
@@ -1503,7 +1503,7 @@ out:
asmlinkage long sys_getpgid(pid_t pid)
{
if (!pid)
- return process_group(current);
+ return pid_to_nr(task_pgrp(current));
else {
int retval;
struct task_struct *p;
@@ -1515,7 +1515,7 @@ asmlinkage long sys_getpgid(pid_t pid)
if (p) {
retval = security_task_getpgid(p);
if (!retval)
- retval = process_group(p);
+ retval = pid_to_nr(task_pgrp(p));
}
read_unlock(&tasklist_lock);
return retval;
@@ -1527,7 +1527,7 @@ asmlinkage long sys_getpgid(pid_t pid)
asmlinkage long sys_getpgrp(void)
{
/* SMP - assuming writes are word atomic this is fine */
- return process_group(current);
+ return pid_to_nr(task_pgrp(current));
}
#endif
@@ -1535,7 +1535,7 @@ asmlinkage long sys_getpgrp(void)
asmlinkage long sys_getsid(pid_t pid)
{
if (!pid)
- return process_session(current);
+ return pid_to_nr(task_session(current));
else {
int retval;
struct task_struct *p;
@@ -1547,7 +1547,7 @@ asmlinkage long sys_getsid(pid_t pid)
if (p) {
retval = security_task_getsid(p);
if (!retval)
- retval = process_session(p);
+ retval = pid_to_nr(task_session(p));
}
read_unlock(&tasklist_lock);
return retval;
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