Fixed MTP to work with TWRP

fs/lockd/mon.c

@@ -0,0 +1,622 @@
+/*
+ * linux/fs/lockd/mon.c
+ *
+ * The kernel statd client.
+ *
+ * Copyright (C) 1996, Olaf Kirch <okir@monad.swb.de>
+ */
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/ktime.h>
+#include <linux/slab.h>
+
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/addr.h>
+#include <linux/sunrpc/xprtsock.h>
+#include <linux/sunrpc/svc.h>
+#include <linux/lockd/lockd.h>
+
+#include <asm/unaligned.h>
+
+#include "netns.h"
+
+#define NLMDBG_FACILITY		NLMDBG_MONITOR
+#define NSM_PROGRAM		100024
+#define NSM_VERSION		1
+
+enum {
+	NSMPROC_NULL,
+	NSMPROC_STAT,
+	NSMPROC_MON,
+	NSMPROC_UNMON,
+	NSMPROC_UNMON_ALL,
+	NSMPROC_SIMU_CRASH,
+	NSMPROC_NOTIFY,
+};
+
+struct nsm_args {
+	struct nsm_private	*priv;
+	u32			prog;		/* RPC callback info */
+	u32			vers;
+	u32			proc;
+
+	char			*mon_name;
+	char			*nodename;
+};
+
+struct nsm_res {
+	u32			status;
+	u32			state;
+};
+
+static const struct rpc_program	nsm_program;
+static				LIST_HEAD(nsm_handles);
+static				DEFINE_SPINLOCK(nsm_lock);
+
+/*
+ * Local NSM state
+ */
+u32	__read_mostly		nsm_local_state;
+bool	__read_mostly		nsm_use_hostnames;
+
+static inline struct sockaddr *nsm_addr(const struct nsm_handle *nsm)
+{
+	return (struct sockaddr *)&nsm->sm_addr;
+}
+
+static struct rpc_clnt *nsm_create(struct net *net, const char *nodename)
+{
+	struct sockaddr_in sin = {
+		.sin_family		= AF_INET,
+		.sin_addr.s_addr	= htonl(INADDR_LOOPBACK),
+	};
+	struct rpc_create_args args = {
+		.net			= net,
+		.protocol		= XPRT_TRANSPORT_TCP,
+		.address		= (struct sockaddr *)&sin,
+		.addrsize		= sizeof(sin),
+		.servername		= "rpc.statd",
+		.nodename		= nodename,
+		.program		= &nsm_program,
+		.version		= NSM_VERSION,
+		.authflavor		= RPC_AUTH_NULL,
+		.flags			= RPC_CLNT_CREATE_NOPING,
+	};
+
+	return rpc_create(&args);
+}
+
+static struct rpc_clnt *nsm_client_set(struct lockd_net *ln,
+		struct rpc_clnt *clnt)
+{
+	spin_lock(&ln->nsm_clnt_lock);
+	if (ln->nsm_users == 0) {
+		if (clnt == NULL)
+			goto out;
+		ln->nsm_clnt = clnt;
+	}
+	clnt = ln->nsm_clnt;
+	ln->nsm_users++;
+out:
+	spin_unlock(&ln->nsm_clnt_lock);
+	return clnt;
+}
+
+static struct rpc_clnt *nsm_client_get(struct net *net, const char *nodename)
+{
+	struct rpc_clnt	*clnt, *new;
+	struct lockd_net *ln = net_generic(net, lockd_net_id);
+
+	clnt = nsm_client_set(ln, NULL);
+	if (clnt != NULL)
+		goto out;
+
+	clnt = new = nsm_create(net, nodename);
+	if (IS_ERR(clnt))
+		goto out;
+
+	clnt = nsm_client_set(ln, new);
+	if (clnt != new)
+		rpc_shutdown_client(new);
+out:
+	return clnt;
+}
+
+static void nsm_client_put(struct net *net)
+{
+	struct lockd_net *ln = net_generic(net, lockd_net_id);
+	struct rpc_clnt	*clnt = NULL;
+
+	spin_lock(&ln->nsm_clnt_lock);
+	ln->nsm_users--;
+	if (ln->nsm_users == 0) {
+		clnt = ln->nsm_clnt;
+		ln->nsm_clnt = NULL;
+	}
+	spin_unlock(&ln->nsm_clnt_lock);
+	if (clnt != NULL)
+		rpc_shutdown_client(clnt);
+}
+
+static int nsm_mon_unmon(struct nsm_handle *nsm, u32 proc, struct nsm_res *res,
+			 struct rpc_clnt *clnt)
+{
+	int		status;
+	struct nsm_args args = {
+		.priv		= &nsm->sm_priv,
+		.prog		= NLM_PROGRAM,
+		.vers		= 3,
+		.proc		= NLMPROC_NSM_NOTIFY,
+		.mon_name	= nsm->sm_mon_name,
+		.nodename	= clnt->cl_nodename,
+	};
+	struct rpc_message msg = {
+		.rpc_argp	= &args,
+		.rpc_resp	= res,
+	};
+
+	memset(res, 0, sizeof(*res));
+
+	msg.rpc_proc = &clnt->cl_procinfo[proc];
+	status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN);
+	if (status == -ECONNREFUSED) {
+		dprintk("lockd:	NSM upcall RPC failed, status=%d, forcing rebind\n",
+				status);
+		rpc_force_rebind(clnt);
+		status = rpc_call_sync(clnt, &msg, RPC_TASK_SOFTCONN);
+	}
+	if (status < 0)
+		dprintk("lockd: NSM upcall RPC failed, status=%d\n",
+				status);
+	else
+		status = 0;
+	return status;
+}
+
+/**
+ * nsm_monitor - Notify a peer in case we reboot
+ * @host: pointer to nlm_host of peer to notify
+ *
+ * If this peer is not already monitored, this function sends an
+ * upcall to the local rpc.statd to record the name/address of
+ * the peer to notify in case we reboot.
+ *
+ * Returns zero if the peer is monitored by the local rpc.statd;
+ * otherwise a negative errno value is returned.
+ */
+int nsm_monitor(const struct nlm_host *host)
+{
+	struct nsm_handle *nsm = host->h_nsmhandle;
+	struct nsm_res	res;
+	int		status;
+	struct rpc_clnt *clnt;
+	const char *nodename = NULL;
+
+	dprintk("lockd: nsm_monitor(%s)\n", nsm->sm_name);
+
+	if (nsm->sm_monitored)
+		return 0;
+
+	if (host->h_rpcclnt)
+		nodename = host->h_rpcclnt->cl_nodename;
+
+	/*
+	 * Choose whether to record the caller_name or IP address of
+	 * this peer in the local rpc.statd's database.
+	 */
+	nsm->sm_mon_name = nsm_use_hostnames ? nsm->sm_name : nsm->sm_addrbuf;
+
+	clnt = nsm_client_get(host->net, nodename);
+	if (IS_ERR(clnt)) {
+		status = PTR_ERR(clnt);
+		dprintk("lockd: failed to create NSM upcall transport, "
+				"status=%d, net=%p\n", status, host->net);
+		return status;
+	}
+
+	status = nsm_mon_unmon(nsm, NSMPROC_MON, &res, clnt);
+	if (unlikely(res.status != 0))
+		status = -EIO;
+	if (unlikely(status < 0)) {
+		printk(KERN_NOTICE "lockd: cannot monitor %s\n", nsm->sm_name);
+		return status;
+	}
+
+	nsm->sm_monitored = 1;
+	if (unlikely(nsm_local_state != res.state)) {
+		nsm_local_state = res.state;
+		dprintk("lockd: NSM state changed to %d\n", nsm_local_state);
+	}
+	return 0;
+}
+
+/**
+ * nsm_unmonitor - Unregister peer notification
+ * @host: pointer to nlm_host of peer to stop monitoring
+ *
+ * If this peer is monitored, this function sends an upcall to
+ * tell the local rpc.statd not to send this peer a notification
+ * when we reboot.
+ */
+void nsm_unmonitor(const struct nlm_host *host)
+{
+	struct nsm_handle *nsm = host->h_nsmhandle;
+	struct nsm_res	res;
+	int status;
+
+	if (atomic_read(&nsm->sm_count) == 1
+	 && nsm->sm_monitored && !nsm->sm_sticky) {
+		struct lockd_net *ln = net_generic(host->net, lockd_net_id);
+
+		dprintk("lockd: nsm_unmonitor(%s)\n", nsm->sm_name);
+
+		status = nsm_mon_unmon(nsm, NSMPROC_UNMON, &res, ln->nsm_clnt);
+		if (res.status != 0)
+			status = -EIO;
+		if (status < 0)
+			printk(KERN_NOTICE "lockd: cannot unmonitor %s\n",
+					nsm->sm_name);
+		else
+			nsm->sm_monitored = 0;
+
+		nsm_client_put(host->net);
+	}
+}
+
+static struct nsm_handle *nsm_lookup_hostname(const char *hostname,
+					      const size_t len)
+{
+	struct nsm_handle *nsm;
+
+	list_for_each_entry(nsm, &nsm_handles, sm_link)
+		if (strlen(nsm->sm_name) == len &&
+		    memcmp(nsm->sm_name, hostname, len) == 0)
+			return nsm;
+	return NULL;
+}
+
+static struct nsm_handle *nsm_lookup_addr(const struct sockaddr *sap)
+{
+	struct nsm_handle *nsm;
+
+	list_for_each_entry(nsm, &nsm_handles, sm_link)
+		if (rpc_cmp_addr(nsm_addr(nsm), sap))
+			return nsm;
+	return NULL;
+}
+
+static struct nsm_handle *nsm_lookup_priv(const struct nsm_private *priv)
+{
+	struct nsm_handle *nsm;
+
+	list_for_each_entry(nsm, &nsm_handles, sm_link)
+		if (memcmp(nsm->sm_priv.data, priv->data,
+					sizeof(priv->data)) == 0)
+			return nsm;
+	return NULL;
+}
+
+/*
+ * Construct a unique cookie to match this nsm_handle to this monitored
+ * host.  It is passed to the local rpc.statd via NSMPROC_MON, and
+ * returned via NLMPROC_SM_NOTIFY, in the "priv" field of these
+ * requests.
+ *
+ * The NSM protocol requires that these cookies be unique while the
+ * system is running.  We prefer a stronger requirement of making them
+ * unique across reboots.  If user space bugs cause a stale cookie to
+ * be sent to the kernel, it could cause the wrong host to lose its
+ * lock state if cookies were not unique across reboots.
+ *
+ * The cookies are exposed only to local user space via loopback.  They
+ * do not appear on the physical network.  If we want greater security
+ * for some reason, nsm_init_private() could perform a one-way hash to
+ * obscure the contents of the cookie.
+ */
+static void nsm_init_private(struct nsm_handle *nsm)
+{
+	u64 *p = (u64 *)&nsm->sm_priv.data;
+	s64 ns;
+
+	ns = ktime_get_ns();
+	put_unaligned(ns, p);
+	put_unaligned((unsigned long)nsm, p + 1);
+}
+
+static struct nsm_handle *nsm_create_handle(const struct sockaddr *sap,
+					    const size_t salen,
+					    const char *hostname,
+					    const size_t hostname_len)
+{
+	struct nsm_handle *new;
+
+	new = kzalloc(sizeof(*new) + hostname_len + 1, GFP_KERNEL);
+	if (unlikely(new == NULL))
+		return NULL;
+
+	atomic_set(&new->sm_count, 1);
+	new->sm_name = (char *)(new + 1);
+	memcpy(nsm_addr(new), sap, salen);
+	new->sm_addrlen = salen;
+	nsm_init_private(new);
+
+	if (rpc_ntop(nsm_addr(new), new->sm_addrbuf,
+					sizeof(new->sm_addrbuf)) == 0)
+		(void)snprintf(new->sm_addrbuf, sizeof(new->sm_addrbuf),
+				"unsupported address family");
+	memcpy(new->sm_name, hostname, hostname_len);
+	new->sm_name[hostname_len] = '\0';
+
+	return new;
+}
+
+/**
+ * nsm_get_handle - Find or create a cached nsm_handle
+ * @sap: pointer to socket address of handle to find
+ * @salen: length of socket address
+ * @hostname: pointer to C string containing hostname to find
+ * @hostname_len: length of C string
+ *
+ * Behavior is modulated by the global nsm_use_hostnames variable.
+ *
+ * Returns a cached nsm_handle after bumping its ref count, or
+ * returns a fresh nsm_handle if a handle that matches @sap and/or
+ * @hostname cannot be found in the handle cache.  Returns NULL if
+ * an error occurs.
+ */
+struct nsm_handle *nsm_get_handle(const struct sockaddr *sap,
+				  const size_t salen, const char *hostname,
+				  const size_t hostname_len)
+{
+	struct nsm_handle *cached, *new = NULL;
+
+	if (hostname && memchr(hostname, '/', hostname_len) != NULL) {
+		if (printk_ratelimit()) {
+			printk(KERN_WARNING "Invalid hostname \"%.*s\" "
+					    "in NFS lock request\n",
+				(int)hostname_len, hostname);
+		}
+		return NULL;
+	}
+
+retry:
+	spin_lock(&nsm_lock);
+
+	if (nsm_use_hostnames && hostname != NULL)
+		cached = nsm_lookup_hostname(hostname, hostname_len);
+	else
+		cached = nsm_lookup_addr(sap);
+
+	if (cached != NULL) {
+		atomic_inc(&cached->sm_count);
+		spin_unlock(&nsm_lock);
+		kfree(new);
+		dprintk("lockd: found nsm_handle for %s (%s), "
+				"cnt %d\n", cached->sm_name,
+				cached->sm_addrbuf,
+				atomic_read(&cached->sm_count));
+		return cached;
+	}
+
+	if (new != NULL) {
+		list_add(&new->sm_link, &nsm_handles);
+		spin_unlock(&nsm_lock);
+		dprintk("lockd: created nsm_handle for %s (%s)\n",
+				new->sm_name, new->sm_addrbuf);
+		return new;
+	}
+
+	spin_unlock(&nsm_lock);
+
+	new = nsm_create_handle(sap, salen, hostname, hostname_len);
+	if (unlikely(new == NULL))
+		return NULL;
+	goto retry;
+}
+
+/**
+ * nsm_reboot_lookup - match NLMPROC_SM_NOTIFY arguments to an nsm_handle
+ * @info: pointer to NLMPROC_SM_NOTIFY arguments
+ *
+ * Returns a matching nsm_handle if found in the nsm cache. The returned
+ * nsm_handle's reference count is bumped. Otherwise returns NULL if some
+ * error occurred.
+ */
+struct nsm_handle *nsm_reboot_lookup(const struct nlm_reboot *info)
+{
+	struct nsm_handle *cached;
+
+	spin_lock(&nsm_lock);
+
+	cached = nsm_lookup_priv(&info->priv);
+	if (unlikely(cached == NULL)) {
+		spin_unlock(&nsm_lock);
+		dprintk("lockd: never saw rebooted peer '%.*s' before\n",
+				info->len, info->mon);
+		return cached;
+	}
+
+	atomic_inc(&cached->sm_count);
+	spin_unlock(&nsm_lock);
+
+	dprintk("lockd: host %s (%s) rebooted, cnt %d\n",
+			cached->sm_name, cached->sm_addrbuf,
+			atomic_read(&cached->sm_count));
+	return cached;
+}
+
+/**
+ * nsm_release - Release an NSM handle
+ * @nsm: pointer to handle to be released
+ *
+ */
+void nsm_release(struct nsm_handle *nsm)
+{
+	if (atomic_dec_and_lock(&nsm->sm_count, &nsm_lock)) {
+		list_del(&nsm->sm_link);
+		spin_unlock(&nsm_lock);
+		dprintk("lockd: destroyed nsm_handle for %s (%s)\n",
+				nsm->sm_name, nsm->sm_addrbuf);
+		kfree(nsm);
+	}
+}
+
+/*
+ * XDR functions for NSM.
+ *
+ * See http://www.opengroup.org/ for details on the Network
+ * Status Monitor wire protocol.
+ */
+
+static void encode_nsm_string(struct xdr_stream *xdr, const char *string)
+{
+	const u32 len = strlen(string);
+	__be32 *p;
+
+	p = xdr_reserve_space(xdr, 4 + len);
+	xdr_encode_opaque(p, string, len);
+}
+
+/*
+ * "mon_name" specifies the host to be monitored.
+ */
+static void encode_mon_name(struct xdr_stream *xdr, const struct nsm_args *argp)
+{
+	encode_nsm_string(xdr, argp->mon_name);
+}
+
+/*
+ * The "my_id" argument specifies the hostname and RPC procedure
+ * to be called when the status manager receives notification
+ * (via the NLMPROC_SM_NOTIFY call) that the state of host "mon_name"
+ * has changed.
+ */
+static void encode_my_id(struct xdr_stream *xdr, const struct nsm_args *argp)
+{
+	__be32 *p;
+
+	encode_nsm_string(xdr, argp->nodename);
+	p = xdr_reserve_space(xdr, 4 + 4 + 4);
+	*p++ = cpu_to_be32(argp->prog);
+	*p++ = cpu_to_be32(argp->vers);
+	*p = cpu_to_be32(argp->proc);
+}
+
+/*
+ * The "mon_id" argument specifies the non-private arguments
+ * of an NSMPROC_MON or NSMPROC_UNMON call.
+ */
+static void encode_mon_id(struct xdr_stream *xdr, const struct nsm_args *argp)
+{
+	encode_mon_name(xdr, argp);
+	encode_my_id(xdr, argp);
+}
+
+/*
+ * The "priv" argument may contain private information required
+ * by the NSMPROC_MON call. This information will be supplied in the
+ * NLMPROC_SM_NOTIFY call.
+ */
+static void encode_priv(struct xdr_stream *xdr, const struct nsm_args *argp)
+{
+	__be32 *p;
+
+	p = xdr_reserve_space(xdr, SM_PRIV_SIZE);
+	xdr_encode_opaque_fixed(p, argp->priv->data, SM_PRIV_SIZE);
+}
+
+static void nsm_xdr_enc_mon(struct rpc_rqst *req, struct xdr_stream *xdr,
+			    const struct nsm_args *argp)
+{
+	encode_mon_id(xdr, argp);
+	encode_priv(xdr, argp);
+}
+
+static void nsm_xdr_enc_unmon(struct rpc_rqst *req, struct xdr_stream *xdr,
+			      const struct nsm_args *argp)
+{
+	encode_mon_id(xdr, argp);
+}
+
+static int nsm_xdr_dec_stat_res(struct rpc_rqst *rqstp,
+				struct xdr_stream *xdr,
+				struct nsm_res *resp)
+{
+	__be32 *p;
+
+	p = xdr_inline_decode(xdr, 4 + 4);
+	if (unlikely(p == NULL))
+		return -EIO;
+	resp->status = be32_to_cpup(p++);
+	resp->state = be32_to_cpup(p);
+
+	dprintk("lockd: %s status %d state %d\n",
+		__func__, resp->status, resp->state);
+	return 0;
+}
+
+static int nsm_xdr_dec_stat(struct rpc_rqst *rqstp,
+			    struct xdr_stream *xdr,
+			    struct nsm_res *resp)
+{
+	__be32 *p;
+
+	p = xdr_inline_decode(xdr, 4);
+	if (unlikely(p == NULL))
+		return -EIO;
+	resp->state = be32_to_cpup(p);
+
+	dprintk("lockd: %s state %d\n", __func__, resp->state);
+	return 0;
+}
+
+#define SM_my_name_sz	(1+XDR_QUADLEN(SM_MAXSTRLEN))
+#define SM_my_id_sz	(SM_my_name_sz+3)
+#define SM_mon_name_sz	(1+XDR_QUADLEN(SM_MAXSTRLEN))
+#define SM_mon_id_sz	(SM_mon_name_sz+SM_my_id_sz)
+#define SM_priv_sz	(XDR_QUADLEN(SM_PRIV_SIZE))
+#define SM_mon_sz	(SM_mon_id_sz+SM_priv_sz)
+#define SM_monres_sz	2
+#define SM_unmonres_sz	1
+
+static struct rpc_procinfo	nsm_procedures[] = {
+[NSMPROC_MON] = {
+		.p_proc		= NSMPROC_MON,
+		.p_encode	= (kxdreproc_t)nsm_xdr_enc_mon,
+		.p_decode	= (kxdrdproc_t)nsm_xdr_dec_stat_res,
+		.p_arglen	= SM_mon_sz,
+		.p_replen	= SM_monres_sz,
+		.p_statidx	= NSMPROC_MON,
+		.p_name		= "MONITOR",
+	},
+[NSMPROC_UNMON] = {
+		.p_proc		= NSMPROC_UNMON,
+		.p_encode	= (kxdreproc_t)nsm_xdr_enc_unmon,
+		.p_decode	= (kxdrdproc_t)nsm_xdr_dec_stat,
+		.p_arglen	= SM_mon_id_sz,
+		.p_replen	= SM_unmonres_sz,
+		.p_statidx	= NSMPROC_UNMON,
+		.p_name		= "UNMONITOR",
+	},
+};
+
+static const struct rpc_version nsm_version1 = {
+		.number		= 1,
+		.nrprocs	= ARRAY_SIZE(nsm_procedures),
+		.procs		= nsm_procedures
+};
+
+static const struct rpc_version *nsm_version[] = {
+	[1] = &nsm_version1,
+};
+
+static struct rpc_stat		nsm_stats;
+
+static const struct rpc_program nsm_program = {
+		.name		= "statd",
+		.number		= NSM_PROGRAM,
+		.nrvers		= ARRAY_SIZE(nsm_version),
+		.version	= nsm_version,
+		.stats		= &nsm_stats
+};