Now we can dump all task or children of a specified task.
It's an example how this interface can be expanded for different
use-cases.
Signed-off-by: Andrey Vagin <ava...@openvz.org>
---
include/uapi/linux/taskdiag.h | 1 +
kernel/taskdiag.c | 83 +++++++++++++++++++++++++++++++++++++------
2 files changed, 73 insertions(+), 11 deletions(-)
diff --git a/include/uapi/linux/taskdiag.h b/include/uapi/linux/taskdiag.h
index db12f6d..d8a9e92 100644
--- a/include/uapi/linux/taskdiag.h
+++ b/include/uapi/linux/taskdiag.h
@@ -68,6 +68,7 @@ enum {
#define TASKDIAG_CMD_MAX (__TASKDIAG_CMD_MAX - 1)
#define TASK_DIAG_DUMP_ALL 0
+#define TASK_DIAG_DUMP_CHILDREN 1
struct task_diag_pid {
__u64 show_flags;
diff --git a/kernel/taskdiag.c b/kernel/taskdiag.c
index 6ccbcaf..951ecbd 100644
--- a/kernel/taskdiag.c
+++ b/kernel/taskdiag.c
@@ -155,12 +155,71 @@ err:
return err;
}
+struct task_iter {
+ struct task_diag_pid *req;
+ struct pid_namespace *ns;
+ struct netlink_callback *cb;
+
+ union {
+ struct tgid_iter tgid;
+ struct child_iter child;
+ };
+};
+
+static struct task_struct *iter_start(struct task_iter *iter)
+{
+ switch (iter->req->dump_stratagy) {
+ case TASK_DIAG_DUMP_CHILDREN:
+ rcu_read_lock();
+ iter->child.parent = find_task_by_pid_ns(iter->req->pid,
iter->ns);
+ if (iter->child.parent)
+ get_task_struct(iter->child.parent);
+ rcu_read_unlock();
+
+ if (iter->child.parent == NULL)
+ return ERR_PTR(-ESRCH);
+
+ iter->child.pos = iter->cb->args[0];
+ iter->child.task = NULL;
+ iter->child = next_child(iter->child);
+ return iter->child.task;
+
+ case TASK_DIAG_DUMP_ALL:
+ iter->tgid.tgid = iter->cb->args[0];
+ iter->tgid.task = NULL;
+ iter->tgid = next_tgid(iter->ns, iter->tgid);
+ return iter->tgid.task;
+ }
+
+ return ERR_PTR(-EINVAL);
+}
+
+static struct task_struct *iter_next(struct task_iter *iter)
+{
+ switch (iter->req->dump_stratagy) {
+ case TASK_DIAG_DUMP_CHILDREN:
+ iter->child.pos += 1;
+ iter->child = next_child(iter->child);
+ iter->cb->args[0] = iter->child.pos;
+ return iter->child.task;
+
+ case TASK_DIAG_DUMP_ALL:
+ iter->tgid.tgid += 1;
+ iter->tgid = next_tgid(iter->ns, iter->tgid);
+ iter->cb->args[0] = iter->tgid.tgid;
+ return iter->tgid.task;
+ }
+
+ return NULL;
+}
+
static int taskdiag_dumpid(struct sk_buff *skb, struct netlink_callback *cb)
{
struct pid_namespace *ns = task_active_pid_ns(current);
- struct tgid_iter iter;
+ struct task_iter iter;
struct nlattr *na;
struct task_diag_pid *req;
+ struct task_struct *task;
int rc;
if (nlmsg_len(cb->nlh) < GENL_HDRLEN + sizeof(*req))
@@ -172,26 +231,28 @@ static int taskdiag_dumpid(struct sk_buff *skb, struct
netlink_callback *cb)
req = (struct task_diag_pid *) nla_data(na);
- iter.tgid = cb->args[0];
- iter.task = NULL;
- for (iter = next_tgid(ns, iter);
- iter.task;
- iter.tgid += 1, iter = next_tgid(ns, iter)) {
- if (!ptrace_may_access(iter.task, PTRACE_MODE_READ))
+ iter.req = req;
+ iter.ns = ns;
+ iter.cb = cb;
+
+ task = iter_start(&iter);
+ if (IS_ERR(task) < 0)
+ return PTR_ERR(task);
+
+ for (; task; task = iter_next(&iter)) {
+ if (!ptrace_may_access(task, PTRACE_MODE_READ))
continue;
- rc = task_diag_fill(iter.task, skb, req->show_flags,
+ rc = task_diag_fill(task, skb, req->show_flags,
NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq);
if (rc < 0) {
- put_task_struct(iter.task);
+ put_task_struct(task);
if (rc != -EMSGSIZE)
return rc;
break;
}
}
- cb->args[0] = iter.tgid;
-
return skb->len;
}
--
2.1.0
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