linux/net/sunrpc/debugfs.c
Jeff Layton 3f94009816 sunrpc: make debugfs file creation failure non-fatal
v2: gracefully handle the case where some dentry pointers end up NULL
    and be more dilligent about zeroing out dentry pointers

We currently have a problem that SELinux policy is being enforced when
creating debugfs files. If a debugfs file is created as a side effect of
doing some syscall, then that creation can fail if the SELinux policy
for that process prevents it.

This seems wrong. We don't do that for files under /proc, for instance,
so Bruce has proposed a patch to fix that.

While discussing that patch however, Greg K.H. stated:

    "No kernel code should care / fail if a debugfs function fails, so
     please fix up the sunrpc code first."

This patch converts all of the sunrpc debugfs setup code to be void
return functins, and the callers to not look for errors from those
functions.

This should allow rpc_clnt and rpc_xprt creation to work, even if the
kernel fails to create debugfs files for some reason.

Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Acked-by: "J. Bruce Fields" <bfields@fieldses.org>
Signed-off-by: Jeff Layton <jeff.layton@primarydata.com>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
2015-04-23 14:42:27 -04:00

299 lines
6.3 KiB
C

/**
* debugfs interface for sunrpc
*
* (c) 2014 Jeff Layton <jlayton@primarydata.com>
*/
#include <linux/debugfs.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/clnt.h>
#include "netns.h"
static struct dentry *topdir;
static struct dentry *rpc_clnt_dir;
static struct dentry *rpc_xprt_dir;
struct rpc_clnt_iter {
struct rpc_clnt *clnt;
loff_t pos;
};
static int
tasks_show(struct seq_file *f, void *v)
{
u32 xid = 0;
struct rpc_task *task = v;
struct rpc_clnt *clnt = task->tk_client;
const char *rpc_waitq = "none";
if (RPC_IS_QUEUED(task))
rpc_waitq = rpc_qname(task->tk_waitqueue);
if (task->tk_rqstp)
xid = be32_to_cpu(task->tk_rqstp->rq_xid);
seq_printf(f, "%5u %04x %6d 0x%x 0x%x %8ld %ps %sv%u %s a:%ps q:%s\n",
task->tk_pid, task->tk_flags, task->tk_status,
clnt->cl_clid, xid, task->tk_timeout, task->tk_ops,
clnt->cl_program->name, clnt->cl_vers, rpc_proc_name(task),
task->tk_action, rpc_waitq);
return 0;
}
static void *
tasks_start(struct seq_file *f, loff_t *ppos)
__acquires(&clnt->cl_lock)
{
struct rpc_clnt_iter *iter = f->private;
loff_t pos = *ppos;
struct rpc_clnt *clnt = iter->clnt;
struct rpc_task *task;
iter->pos = pos + 1;
spin_lock(&clnt->cl_lock);
list_for_each_entry(task, &clnt->cl_tasks, tk_task)
if (pos-- == 0)
return task;
return NULL;
}
static void *
tasks_next(struct seq_file *f, void *v, loff_t *pos)
{
struct rpc_clnt_iter *iter = f->private;
struct rpc_clnt *clnt = iter->clnt;
struct rpc_task *task = v;
struct list_head *next = task->tk_task.next;
++iter->pos;
++*pos;
/* If there's another task on list, return it */
if (next == &clnt->cl_tasks)
return NULL;
return list_entry(next, struct rpc_task, tk_task);
}
static void
tasks_stop(struct seq_file *f, void *v)
__releases(&clnt->cl_lock)
{
struct rpc_clnt_iter *iter = f->private;
struct rpc_clnt *clnt = iter->clnt;
spin_unlock(&clnt->cl_lock);
}
static const struct seq_operations tasks_seq_operations = {
.start = tasks_start,
.next = tasks_next,
.stop = tasks_stop,
.show = tasks_show,
};
static int tasks_open(struct inode *inode, struct file *filp)
{
int ret = seq_open_private(filp, &tasks_seq_operations,
sizeof(struct rpc_clnt_iter));
if (!ret) {
struct seq_file *seq = filp->private_data;
struct rpc_clnt_iter *iter = seq->private;
iter->clnt = inode->i_private;
if (!atomic_inc_not_zero(&iter->clnt->cl_count)) {
seq_release_private(inode, filp);
ret = -EINVAL;
}
}
return ret;
}
static int
tasks_release(struct inode *inode, struct file *filp)
{
struct seq_file *seq = filp->private_data;
struct rpc_clnt_iter *iter = seq->private;
rpc_release_client(iter->clnt);
return seq_release_private(inode, filp);
}
static const struct file_operations tasks_fops = {
.owner = THIS_MODULE,
.open = tasks_open,
.read = seq_read,
.llseek = seq_lseek,
.release = tasks_release,
};
void
rpc_clnt_debugfs_register(struct rpc_clnt *clnt)
{
int len;
char name[24]; /* enough for "../../rpc_xprt/ + 8 hex digits + NULL */
struct rpc_xprt *xprt;
/* Already registered? */
if (clnt->cl_debugfs || !rpc_clnt_dir)
return;
len = snprintf(name, sizeof(name), "%x", clnt->cl_clid);
if (len >= sizeof(name))
return;
/* make the per-client dir */
clnt->cl_debugfs = debugfs_create_dir(name, rpc_clnt_dir);
if (!clnt->cl_debugfs)
return;
/* make tasks file */
if (!debugfs_create_file("tasks", S_IFREG | S_IRUSR, clnt->cl_debugfs,
clnt, &tasks_fops))
goto out_err;
rcu_read_lock();
xprt = rcu_dereference(clnt->cl_xprt);
/* no "debugfs" dentry? Don't bother with the symlink. */
if (!xprt->debugfs) {
rcu_read_unlock();
return;
}
len = snprintf(name, sizeof(name), "../../rpc_xprt/%s",
xprt->debugfs->d_name.name);
rcu_read_unlock();
if (len >= sizeof(name))
goto out_err;
if (!debugfs_create_symlink("xprt", clnt->cl_debugfs, name))
goto out_err;
return;
out_err:
debugfs_remove_recursive(clnt->cl_debugfs);
clnt->cl_debugfs = NULL;
}
void
rpc_clnt_debugfs_unregister(struct rpc_clnt *clnt)
{
debugfs_remove_recursive(clnt->cl_debugfs);
clnt->cl_debugfs = NULL;
}
static int
xprt_info_show(struct seq_file *f, void *v)
{
struct rpc_xprt *xprt = f->private;
seq_printf(f, "netid: %s\n", xprt->address_strings[RPC_DISPLAY_NETID]);
seq_printf(f, "addr: %s\n", xprt->address_strings[RPC_DISPLAY_ADDR]);
seq_printf(f, "port: %s\n", xprt->address_strings[RPC_DISPLAY_PORT]);
seq_printf(f, "state: 0x%lx\n", xprt->state);
return 0;
}
static int
xprt_info_open(struct inode *inode, struct file *filp)
{
int ret;
struct rpc_xprt *xprt = inode->i_private;
ret = single_open(filp, xprt_info_show, xprt);
if (!ret) {
if (!xprt_get(xprt)) {
single_release(inode, filp);
ret = -EINVAL;
}
}
return ret;
}
static int
xprt_info_release(struct inode *inode, struct file *filp)
{
struct rpc_xprt *xprt = inode->i_private;
xprt_put(xprt);
return single_release(inode, filp);
}
static const struct file_operations xprt_info_fops = {
.owner = THIS_MODULE,
.open = xprt_info_open,
.read = seq_read,
.llseek = seq_lseek,
.release = xprt_info_release,
};
void
rpc_xprt_debugfs_register(struct rpc_xprt *xprt)
{
int len, id;
static atomic_t cur_id;
char name[9]; /* 8 hex digits + NULL term */
if (!rpc_xprt_dir)
return;
id = (unsigned int)atomic_inc_return(&cur_id);
len = snprintf(name, sizeof(name), "%x", id);
if (len >= sizeof(name))
return;
/* make the per-client dir */
xprt->debugfs = debugfs_create_dir(name, rpc_xprt_dir);
if (!xprt->debugfs)
return;
/* make tasks file */
if (!debugfs_create_file("info", S_IFREG | S_IRUSR, xprt->debugfs,
xprt, &xprt_info_fops)) {
debugfs_remove_recursive(xprt->debugfs);
xprt->debugfs = NULL;
}
}
void
rpc_xprt_debugfs_unregister(struct rpc_xprt *xprt)
{
debugfs_remove_recursive(xprt->debugfs);
xprt->debugfs = NULL;
}
void __exit
sunrpc_debugfs_exit(void)
{
debugfs_remove_recursive(topdir);
topdir = NULL;
rpc_clnt_dir = NULL;
rpc_xprt_dir = NULL;
}
void __init
sunrpc_debugfs_init(void)
{
topdir = debugfs_create_dir("sunrpc", NULL);
if (!topdir)
return;
rpc_clnt_dir = debugfs_create_dir("rpc_clnt", topdir);
if (!rpc_clnt_dir)
goto out_remove;
rpc_xprt_dir = debugfs_create_dir("rpc_xprt", topdir);
if (!rpc_xprt_dir)
goto out_remove;
return;
out_remove:
debugfs_remove_recursive(topdir);
topdir = NULL;
rpc_clnt_dir = NULL;
}