signal: Introduce kill_pid_ns_info

Author: Eric W. Biederman <[email protected]>

Implement the basic helper function that walks all of the processes in a pid namespace and sends them all a signal.

Both locations that could use this functions are also updated to use this function.

I use find_ge_pid instead of for_each_process because it has a chance of not touching every process in the system.

index ba2f859..83597f8 100644
@@ -1778,6 +1778,8 @@ extern void release_task(struct task_struct * p);
 extern int send_sig_info(int, struct siginfo *, struct task_struct *);

extern int force_sigsegv(int, struct task_struct *);
extern int force_sig_info(int, struct siginfo *, struct task_struct *);
+extern int __kill_pid_ns_info(int sig, struct siginfo *info, struct pid_namespace *ns);
+extern int kill_pid_ns_info(int sig, struct siginfo *info, struct pid_namespace *ns);
extern int __kill_pgrp_info(int sig, struct siginfo *info, struct pid
*pgrp);
extern int kill_pid_info(int sig, struct siginfo *info, struct pid *pid);
extern int kill_pid_info_as_uid(int, struct siginfo *, struct pid *, uid_t, uid_t, u32);

index 98702b4..9226423 100644
@@ -153,29 +153,14 @@ void free_pid_ns(struct kref *kref)
 
 void zap_pid_ns_processes(struct pid_namespace *pid_ns)
 {
-	int nr;
 	int rc;
 
 	/*
 	 * The last thread in the cgroup-init thread group is terminating. *

Find remaining pid_ts in the namespace, signal and wait for them * to exit.
- *
- * Note: This signals each threads in the namespace - even those that
- * belong to the same thread group, To avoid this, we would have - *
to walk the entire tasklist looking a processes in this
- * namespace, but that could be unnecessarily expensive if the - *
pid namespace has just a few processes. Or we need to
- * maintain a tasklist for each pid namespace.
- *
*/
- read_lock(&tasklist_lock);
- nr = next_pidmap(pid_ns, 1);
- while (nr > 0) {
- kill_proc_info(SIGKILL, SEND_SIG_PRIV, nr);
- nr = next_pidmap(pid_ns, nr);
- }
- read_unlock(&tasklist_lock);
+ kill_pid_ns_info(SIGKILL, SEND_SIG_PRIV, pid_ns);

do {
clear_thread_flag(TIF_SIGPENDING);

index 6c0958e..fc42428 100644
@@ -1118,6 +1118,45 @@ out_unlock:
 }
 EXPORT_SYMBOL_GPL(kill_pid_info_as_uid);
 
+int __kill_pid_ns_info(int sig, struct siginfo *info, struct

pid_namespace *ns)
+{
+ int retval = 0, count = 0;
+ struct task_struct *p;
+ struct pid *pid;
+ int nr;
+
+ /* Since there isn't a pid namespace list of tasks use the closest + *
approximation we have: find_ge_pid.
+ */
+ nr = 1;
+ while ((pid = find_ge_pid(nr + 1, ns))) {
+ int err;
+
+ nr = pid_nr_ns(pid, ns);
+ p = pid_task(pid, PIDTYPE_PID);
+ if (!p || (nr <= 1) || !thread_group_leader(p) ||
+ same_thread_group(p, current))
+ continue;
+
+ err = group_send_sig_info(sig, info, p);
+ ++count;
+ if (err != -EPERM)
+ retval = err;
+ }
+ return count ? retval : -ESRCH;
+}
+
+int kill_pid_ns_info(int sig, struct siginfo *info, struct pid_namespace *ns)
+{
+ int retval;
+
+ read_lock(&tasklist_lock);
+ retval = __kill_pid_ns_info(sig, info, ns);
+ read_unlock(&tasklist_lock);
+
+ return retval;
+}
+
/*
* kill_something_info() interprets pid in interesting ways just like
kill(2).
*
@@ -1141,18 +1180,7 @@ static int kill_something_info(int sig, struct siginfo *info, int pid)
ret = __kill_pgrp_info(sig, info,
pid ? find_vpid(-pid) : task_pgrp(current));
} else {
- int retval = 0, count = 0;
- struct task_struct * p;
-
- for_each_process(p) {
- if (p->pid > 1 && !same_thread_group(p, current)) {
- int err = group_send_sig_info(sig, info, p);
- ++count;
- if (err != -EPERM)
- retval = err;
- }
- }
- ret = count ? retval : -ESRCH;
+ ret = __kill_pid_ns_info(sig, info, task_active_pid_ns(current));
}
read_unlock(&tasklist_lock);

1.5.5.1

I'm sorry Andrew, this should look better.

Author: Eric W. Biederman <ebiederm-aS9lmoZGLiVWk0Htik3J/[email protected]>

Implement the basic helper function that walks all of the processes in a pid namespace and sends them all a signal.

Both locations that could use this functions are also updated to use this function.

I use find_ge_pid instead of for_each_process because it has a chance of not touching every process in the system.

---
  include/linux/sched.h  |    2 +
  kernel/pid_namespace.c |   17 +--------------
  kernel/signal.c        |   52 ++++++++++++++++++++++++++++++++++++-----------
  3 files changed, 43 insertions(+), 28 deletions(-)

index ba2f859..83597f8 100644
@@ -1778,6 +1778,8 @@ extern void release_task(struct task_struct * p);
  extern int send_sig_info(int, struct siginfo *, struct task_struct *);
  extern int force_sigsegv(int, struct task_struct *);
  extern int force_sig_info(int, struct siginfo *, struct task_struct *);
+extern int __kill_pid_ns_info(int sig, struct siginfo *info, struct pid_namespace *ns);
+extern int kill_pid_ns_info(int sig, struct siginfo *info, struct pid_namespace *ns);
  extern int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp);
  extern int kill_pid_info(int sig, struct siginfo *info, struct pid *pid);
  extern int kill_pid_info_as_uid(int, struct siginfo *, struct pid *, uid_t, uid_t, u32);

index 98702b4..9226423 100644
@@ -153,29 +153,14 @@ void free_pid_ns(struct kref *kref)
 
  void zap_pid_ns_processes(struct pid_namespace *pid_ns)
  {
-	int nr;
  	int rc;
 
  	/*
  	 * The last thread in the cgroup-init thread group is terminating.
  	 * Find remaining pid_ts in the namespace, signal and wait for them
  	 * to exit.
-	 *
-	 * Note:  This signals each threads in the namespace - even those that
-	 * 	  belong to the same thread group, To avoid this, we would have
-	 * 	  to walk the entire tasklist looking a processes in this
-	 * 	  namespace, but that could be unnecessarily expensive if the
-	 * 	  pid namespace has just a few processes. Or we need to
-	 * 	  maintain a tasklist for each pid namespace.
-	 *
  	 */
-	read_lock(&tasklist_lock);
-	nr = next_pidmap(pid_ns, 1);
-	while (nr > 0) {
-		kill_proc_info(SIGKILL, SEND_SIG_PRIV, nr);
-		nr = next_pidmap(pid_ns, nr);
-	}
-	read_unlock(&tasklist_lock);
+	kill_pid_ns_info(SIGKILL, SEND_SIG_PRIV, pid_ns);
 
  	do {
  		clear_thread_flag(TIF_SIGPENDING);

1.5.5.1

I'm sorry Andrew, this should look better.

Author: Eric W. Biederman <[email protected]>

Implement the basic helper function that walks all of the processes in a pid namespace and sends them all a signal.

Both locations that could use this functions are also updated to use this function.

I use find_ge_pid instead of for_each_process because it has a chance of not touching every process in the system.

---
 include/linux/sched.h  |    2 +
 kernel/pid_namespace.c |   17 +--------------
 kernel/signal.c        |   52 ++++++++++++++++++++++++++++++++++++-----------
 3 files changed, 43 insertions(+), 28 deletions(-)

index ba2f859..83597f8 100644
@@ -1778,6 +1778,8 @@ extern void release_task(struct task_struct * p);
 extern int send_sig_info(int, struct siginfo *, struct task_struct *);
 extern int force_sigsegv(int, struct task_struct *);
 extern int force_sig_info(int, struct siginfo *, struct task_struct *);
+extern int __kill_pid_ns_info(int sig, struct siginfo *info, struct pid_namespace *ns);
+extern int kill_pid_ns_info(int sig, struct siginfo *info, struct pid_namespace *ns);
 extern int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp);
 extern int kill_pid_info(int sig, struct siginfo *info, struct pid *pid);
 extern int kill_pid_info_as_uid(int, struct siginfo *, struct pid *, uid_t, uid_t, u32);

index 98702b4..9226423 100644
@@ -153,29 +153,14 @@ void free_pid_ns(struct kref *kref)
 
 void zap_pid_ns_processes(struct pid_namespace *pid_ns)
 {
-	int nr;
 	int rc;
 
 	/*
 	 * The last thread in the cgroup-init thread group is terminating.
 	 * Find remaining pid_ts in the namespace, signal and wait for them
 	 * to exit.
-	 *
-	 * Note:  This signals each threads in the namespace - even those that
-	 * 	  belong to the same thread group, To avoid this, we would have
-	 * 	  to walk the entire tasklist looking a processes in this
-	 * 	  namespace, but that could be unnecessarily expensive if the
-	 * 	  pid namespace has just a few processes. Or we need to
-	 * 	  maintain a tasklist for each pid namespace.
-	 *
 	 */
-	read_lock(&tasklist_lock);
-	nr = next_pidmap(pid_ns, 1);
-	while (nr > 0) {
-		kill_proc_info(SIGKILL, SEND_SIG_PRIV, nr);
-		nr = next_pidmap(pid_ns, nr);
-	}
-	read_unlock(&tasklist_lock);
+	kill_pid_ns_info(SIGKILL, SEND_SIG_PRIV, pid_ns);
 
 	do {
 		clear_thread_flag(TIF_SIGPENDING);

1.5.5.1