[linux-2.6-block.git] / drivers / staging / lustre / lustre / libcfs / kernel_user_comm.c

/*
 * GPL HEADER START
 *
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 only,
 * as published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License version 2 for more details (a copy is included
 * in the LICENSE file that accompanied this code).
 *
 * You should have received a copy of the GNU General Public License
 * version 2 along with this program; If not, see
 * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
 *
 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
 * CA 95054 USA or visit www.sun.com if you need additional information or
 * have any questions.
 *
 * GPL HEADER END
 */
/*
 * Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
 * Use is subject to license terms.
 *
 * Copyright (c) 2012, Intel Corporation.
 */
/*
 * This file is part of Lustre, http://www.lustre.org/
 * Lustre is a trademark of Sun Microsystems, Inc.
 *
 * Author: Nathan Rutman <nathan.rutman@sun.com>
 *
 * Kernel <-> userspace communication routines.
 * Using pipes for all arches.
 */

#define DEBUG_SUBSYSTEM S_CLASS
#define D_KUC D_OTHER

#include <linux/libcfs/libcfs.h>

#ifdef LUSTRE_UTILS
/* This is the userspace side. */

/** Start the userspace side of a KUC pipe.
 * @param link Private descriptor for pipe/socket.
 * @param groups KUC broadcast group to listen to
 *	  (can be null for unicast to this pid)
 */
int libcfs_ukuc_start(lustre_kernelcomm *link, int group)
{
	int pfd[2];

	if (pipe(pfd) < 0)
		return -errno;

	memset(link, 0, sizeof(*link));
	link->lk_rfd = pfd[0];
	link->lk_wfd = pfd[1];
	link->lk_group = group;
	link->lk_uid = getpid();
	return 0;
}

int libcfs_ukuc_stop(lustre_kernelcomm *link)
{
	if (link->lk_wfd > 0)
		close(link->lk_wfd);
	return close(link->lk_rfd);
}

#define lhsz sizeof(*kuch)

/** Read a message from the link.
 * Allocates memory, returns handle
 *
 * @param link Private descriptor for pipe/socket.
 * @param buf Buffer to read into, must include size for kuc_hdr
 * @param maxsize Maximum message size allowed
 * @param transport Only listen to messages on this transport
 *      (and the generic transport)
 */
int libcfs_ukuc_msg_get(lustre_kernelcomm *link, char *buf, int maxsize,
			int transport)
{
	struct kuc_hdr *kuch;
	int rc = 0;

	memset(buf, 0, maxsize);

	CDEBUG(D_KUC, "Waiting for message from kernel on fd %d\n",
	       link->lk_rfd);

	while (1) {
		/* Read header first to get message size */
		rc = read(link->lk_rfd, buf, lhsz);
		if (rc <= 0) {
			rc = -errno;
			break;
		}
		kuch = (struct kuc_hdr *)buf;

		CDEBUG(D_KUC, "Received message mg=%x t=%d m=%d l=%d\n",
		       kuch->kuc_magic, kuch->kuc_transport, kuch->kuc_msgtype,
		       kuch->kuc_msglen);

		if (kuch->kuc_magic != KUC_MAGIC) {
			CERROR("bad message magic %x != %x\n",
			       kuch->kuc_magic, KUC_MAGIC);
			rc = -EPROTO;
			break;
		}

		if (kuch->kuc_msglen > maxsize) {
			rc = -EMSGSIZE;
			break;
		}

		/* Read payload */
		rc = read(link->lk_rfd, buf + lhsz, kuch->kuc_msglen - lhsz);
		if (rc < 0) {
			rc = -errno;
			break;
		}
		if (rc < (kuch->kuc_msglen - lhsz)) {
			CERROR("short read: got %d of %d bytes\n",
			       rc, kuch->kuc_msglen);
			rc = -EPROTO;
			break;
		}

		if (kuch->kuc_transport == transport ||
		    kuch->kuc_transport == KUC_TRANSPORT_GENERIC) {
			return 0;
		}
		/* Drop messages for other transports */
	}
	return rc;
}

#else /* LUSTRE_UTILS */
/* This is the kernel side (liblustre as well). */

/**
 * libcfs_kkuc_msg_put - send an message from kernel to userspace
 * @param fp to send the message to
 * @param payload Payload data.  First field of payload is always
 *   struct kuc_hdr
 */
int libcfs_kkuc_msg_put(struct file *filp, void *payload)
{
	struct kuc_hdr *kuch = (struct kuc_hdr *)payload;
	ssize_t count = kuch->kuc_msglen;
	loff_t offset = 0;
	mm_segment_t fs;
	int rc = -ENOSYS;

	if (filp == NULL || IS_ERR(filp))
		return -EBADF;

	if (kuch->kuc_magic != KUC_MAGIC) {
		CERROR("KernelComm: bad magic %x\n", kuch->kuc_magic);
		return -ENOSYS;
	}

	fs = get_fs();
	set_fs(KERNEL_DS);
	while (count > 0) {
		rc = vfs_write(filp, (void __force __user *)payload,
			       count, &offset);
		if (rc < 0)
			break;
		count -= rc;
		payload += rc;
		rc = 0;
	}
	set_fs(fs);

	if (rc < 0)
		CWARN("message send failed (%d)\n", rc);
	else
		CDEBUG(D_KUC, "Sent message rc=%d, fp=%p\n", rc, filp);

	return rc;
}
EXPORT_SYMBOL(libcfs_kkuc_msg_put);

/* Broadcast groups are global across all mounted filesystems;
 * i.e. registering for a group on 1 fs will get messages for that
 * group from any fs */
/** A single group reigstration has a uid and a file pointer */
struct kkuc_reg {
	struct list_head	kr_chain;
	int		kr_uid;
	struct file	*kr_fp;
	__u32		kr_data;
};
static struct list_head kkuc_groups[KUC_GRP_MAX+1] = {};
/* Protect message sending against remove and adds */
static DECLARE_RWSEM(kg_sem);

/** Add a receiver to a broadcast group
 * @param filp pipe to write into
 * @param uid identidier for this receiver
 * @param group group number
 */
int libcfs_kkuc_group_add(struct file *filp, int uid, int group, __u32 data)
{
	struct kkuc_reg *reg;

	if (group > KUC_GRP_MAX) {
		CDEBUG(D_WARNING, "Kernelcomm: bad group %d\n", group);
		return -EINVAL;
	}

	/* fput in group_rem */
	if (filp == NULL)
		return -EBADF;

	/* freed in group_rem */
	reg = kmalloc(sizeof(*reg), 0);
	if (reg == NULL)
		return -ENOMEM;

	reg->kr_fp = filp;
	reg->kr_uid = uid;
	reg->kr_data = data;

	down_write(&kg_sem);
	if (kkuc_groups[group].next == NULL)
		INIT_LIST_HEAD(&kkuc_groups[group]);
	list_add(&reg->kr_chain, &kkuc_groups[group]);
	up_write(&kg_sem);

	CDEBUG(D_KUC, "Added uid=%d fp=%p to group %d\n", uid, filp, group);

	return 0;
}
EXPORT_SYMBOL(libcfs_kkuc_group_add);

int libcfs_kkuc_group_rem(int uid, int group)
{
	struct kkuc_reg *reg, *next;

	if (kkuc_groups[group].next == NULL)
		return 0;

	if (uid == 0) {
		/* Broadcast a shutdown message */
		struct kuc_hdr lh;

		lh.kuc_magic = KUC_MAGIC;
		lh.kuc_transport = KUC_TRANSPORT_GENERIC;
		lh.kuc_msgtype = KUC_MSG_SHUTDOWN;
		lh.kuc_msglen = sizeof(lh);
		libcfs_kkuc_group_put(group, &lh);
	}

	down_write(&kg_sem);
	list_for_each_entry_safe(reg, next, &kkuc_groups[group], kr_chain) {
		if ((uid == 0) || (uid == reg->kr_uid)) {
			list_del(&reg->kr_chain);
			CDEBUG(D_KUC, "Removed uid=%d fp=%p from group %d\n",
			       reg->kr_uid, reg->kr_fp, group);
			if (reg->kr_fp != NULL)
				fput(reg->kr_fp);
			kfree(reg);
		}
	}
	up_write(&kg_sem);

	return 0;
}
EXPORT_SYMBOL(libcfs_kkuc_group_rem);

int libcfs_kkuc_group_put(int group, void *payload)
{
	struct kkuc_reg	*reg;
	int		 rc = 0;
	int one_success = 0;

	down_read(&kg_sem);
	list_for_each_entry(reg, &kkuc_groups[group], kr_chain) {
		if (reg->kr_fp != NULL) {
			rc = libcfs_kkuc_msg_put(reg->kr_fp, payload);
			if (rc == 0)
				one_success = 1;
			else if (rc == -EPIPE) {
				fput(reg->kr_fp);
				reg->kr_fp = NULL;
			}
		}
	}
	up_read(&kg_sem);

	/* don't return an error if the message has been delivered
	 * at least to one agent */
	if (one_success)
		rc = 0;

	return rc;
}
EXPORT_SYMBOL(libcfs_kkuc_group_put);

/**
 * Calls a callback function for each link of the given kuc group.
 * @param group the group to call the function on.
 * @param cb_func the function to be called.
 * @param cb_arg iextra argument to be passed to the callback function.
 */
int libcfs_kkuc_group_foreach(int group, libcfs_kkuc_cb_t cb_func,
			      void *cb_arg)
{
	struct kkuc_reg *reg;
	int rc = 0;

	if (group > KUC_GRP_MAX) {
		CDEBUG(D_WARNING, "Kernelcomm: bad group %d\n", group);
		return -EINVAL;
	}

	/* no link for this group */
	if (kkuc_groups[group].next == NULL)
		return 0;

	down_read(&kg_sem);
	list_for_each_entry(reg, &kkuc_groups[group], kr_chain) {
		if (reg->kr_fp != NULL) {
			rc = cb_func(reg->kr_data, cb_arg);
		}
	}
	up_read(&kg_sem);

	return rc;
}
EXPORT_SYMBOL(libcfs_kkuc_group_foreach);

#endif /* LUSTRE_UTILS */
Commit	Line	Data
d7e09d03 PT	1	/*
	2	* GPL HEADER START
	3	*
	4	* DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License version 2 only,
	8	* as published by the Free Software Foundation.
	9	*
	10	* This program is distributed in the hope that it will be useful, but
	11	* WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	* General Public License version 2 for more details (a copy is included
	14	* in the LICENSE file that accompanied this code).
	15	*
	16	* You should have received a copy of the GNU General Public License
	17	* version 2 along with this program; If not, see
	18	* http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
	19	*
	20	* Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
	21	* CA 95054 USA or visit www.sun.com if you need additional information or
	22	* have any questions.
	23	*
	24	* GPL HEADER END
	25	*/
	26	/*
	27	* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
	28	* Use is subject to license terms.
	29	*
	30	* Copyright (c) 2012, Intel Corporation.
	31	*/
	32	/*
	33	* This file is part of Lustre, http://www.lustre.org/
	34	* Lustre is a trademark of Sun Microsystems, Inc.
	35	*
	36	* Author: Nathan Rutman <nathan.rutman@sun.com>
	37	*
	38	* Kernel <-> userspace communication routines.
	39	* Using pipes for all arches.
	40	*/
	41
	42	#define DEBUG_SUBSYSTEM S_CLASS
	43	#define D_KUC D_OTHER
	44
	45	#include <linux/libcfs/libcfs.h>
	46
	47	#ifdef LUSTRE_UTILS
	48	/* This is the userspace side. */
	49
	50	/** Start the userspace side of a KUC pipe.
	51	* @param link Private descriptor for pipe/socket.
	52	* @param groups KUC broadcast group to listen to
	53	* (can be null for unicast to this pid)
	54	*/
	55	int libcfs_ukuc_start(lustre_kernelcomm *link, int group)
	56	{
	57	int pfd[2];
	58
	59	if (pipe(pfd) < 0)
	60	return -errno;
	61
	62	memset(link, 0, sizeof(*link));
	63	link->lk_rfd = pfd[0];
	64	link->lk_wfd = pfd[1];
65	link->lk_group = group;
66	link->lk_uid = getpid();
67	return 0;
68	}
69
70	int libcfs_ukuc_stop(lustre_kernelcomm *link)
71	{
72	if (link->lk_wfd > 0)
73	close(link->lk_wfd);
74	return close(link->lk_rfd);
75	}
76
77	#define lhsz sizeof(*kuch)
78
79	/** Read a message from the link.
80	* Allocates memory, returns handle
81	*
82	* @param link Private descriptor for pipe/socket.
83	* @param buf Buffer to read into, must include size for kuc_hdr
84	* @param maxsize Maximum message size allowed
85	* @param transport Only listen to messages on this transport
86	* (and the generic transport)
87	*/
88	int libcfs_ukuc_msg_get(lustre_kernelcomm link, char buf, int maxsize,
89	int transport)
90	{
91	struct kuc_hdr *kuch;
92	int rc = 0;
93
94	memset(buf, 0, maxsize);
95
96	CDEBUG(D_KUC, "Waiting for message from kernel on fd %d\n",
97	link->lk_rfd);
98
99	while (1) {
100	/* Read header first to get message size */
101	rc = read(link->lk_rfd, buf, lhsz);
102	if (rc <= 0) {
103	rc = -errno;
104	break;
105	}
106	kuch = (struct kuc_hdr *)buf;
107
108	CDEBUG(D_KUC, "Received message mg=%x t=%d m=%d l=%d\n",
109	kuch->kuc_magic, kuch->kuc_transport, kuch->kuc_msgtype,
110	kuch->kuc_msglen);
111
112	if (kuch->kuc_magic != KUC_MAGIC) {
113	CERROR("bad message magic %x != %x\n",
114	kuch->kuc_magic, KUC_MAGIC);
115	rc = -EPROTO;
116	break;
117	}
118
119	if (kuch->kuc_msglen > maxsize) {
120	rc = -EMSGSIZE;
121	break;
122	}
123
124	/* Read payload */
125	rc = read(link->lk_rfd, buf + lhsz, kuch->kuc_msglen - lhsz);
126	if (rc < 0) {
127	rc = -errno;
128	break;
129	}
130	if (rc < (kuch->kuc_msglen - lhsz)) {
131	CERROR("short read: got %d of %d bytes\n",
132	rc, kuch->kuc_msglen);
133	rc = -EPROTO;
134	break;
135	}
136
137	if (kuch->kuc_transport == transport \|\|
138	kuch->kuc_transport == KUC_TRANSPORT_GENERIC) {
139	return 0;
140	}
141	/* Drop messages for other transports */
142	}
143	return rc;
144	}
145
146	#else /* LUSTRE_UTILS */
147	/* This is the kernel side (liblustre as well). */
148
149	/**
150	* libcfs_kkuc_msg_put - send an message from kernel to userspace
151	* @param fp to send the message to
152	* @param payload Payload data. First field of payload is always
153	* struct kuc_hdr
154	*/
155	int libcfs_kkuc_msg_put(struct file filp, void payload)
156	{
157	struct kuc_hdr kuch = (struct kuc_hdr )payload;
7d5ed06b PT	158	ssize_t count = kuch->kuc_msglen;
	159	loff_t offset = 0;
	160	mm_segment_t fs;
d7e09d03 PT	161	int rc = -ENOSYS;
	162
	163	if (filp == NULL \|\| IS_ERR(filp))
	164	return -EBADF;
	165
	166	if (kuch->kuc_magic != KUC_MAGIC) {
	167	CERROR("KernelComm: bad magic %x\n", kuch->kuc_magic);
	168	return -ENOSYS;
	169	}
	170
7d5ed06b PT	171	fs = get_fs();
7d5ed06b PT	172	set_fs(KERNEL_DS);
e543d2ea PT	173	while (count > 0) {
e543d2ea PT	174	rc = vfs_write(filp, (void __force __user *)payload,
7d5ed06b PT	175	count, &offset);
	176	if (rc < 0)
	177	break;
	178	count -= rc;
	179	payload += rc;
	180	rc = 0;
d7e09d03	181	}
7d5ed06b	182	set_fs(fs);
d7e09d03 PT	183
	184	if (rc < 0)
	185	CWARN("message send failed (%d)\n", rc);
	186	else
	187	CDEBUG(D_KUC, "Sent message rc=%d, fp=%p\n", rc, filp);
	188
	189	return rc;
	190	}
	191	EXPORT_SYMBOL(libcfs_kkuc_msg_put);
	192
	193	/* Broadcast groups are global across all mounted filesystems;
	194	* i.e. registering for a group on 1 fs will get messages for that
	195	* group from any fs */
	196	/** A single group reigstration has a uid and a file pointer */
	197	struct kkuc_reg {
	198	struct list_head kr_chain;
	199	int kr_uid;
	200	struct file *kr_fp;
	201	__u32 kr_data;
	202	};
	203	static struct list_head kkuc_groups[KUC_GRP_MAX+1] = {};
	204	/* Protect message sending against remove and adds */
	205	static DECLARE_RWSEM(kg_sem);
	206
	207	/** Add a receiver to a broadcast group
	208	* @param filp pipe to write into
	209	* @param uid identidier for this receiver
	210	* @param group group number
	211	*/
	212	int libcfs_kkuc_group_add(struct file *filp, int uid, int group, __u32 data)
	213	{
	214	struct kkuc_reg *reg;
	215
	216	if (group > KUC_GRP_MAX) {
	217	CDEBUG(D_WARNING, "Kernelcomm: bad group %d\n", group);
	218	return -EINVAL;
	219	}
	220
	221	/* fput in group_rem */
	222	if (filp == NULL)
	223	return -EBADF;
	224
	225	/* freed in group_rem */
	226	reg = kmalloc(sizeof(*reg), 0);
	227	if (reg == NULL)
	228	return -ENOMEM;
	229
	230	reg->kr_fp = filp;
	231	reg->kr_uid = uid;
	232	reg->kr_data = data;
	233
	234	down_write(&kg_sem);
	235	if (kkuc_groups[group].next == NULL)
	236	INIT_LIST_HEAD(&kkuc_groups[group]);
	237	list_add(&reg->kr_chain, &kkuc_groups[group]);
	238	up_write(&kg_sem);
	239
	240	CDEBUG(D_KUC, "Added uid=%d fp=%p to group %d\n", uid, filp, group);
	241
	242	return 0;
	243	}
	244	EXPORT_SYMBOL(libcfs_kkuc_group_add);
	245
	246	int libcfs_kkuc_group_rem(int uid, int group)
247	{
248	struct kkuc_reg reg, next;
d7e09d03 PT	249
d7e09d03 PT	250	if (kkuc_groups[group].next == NULL)
0a3bdb00	251	return 0;
d7e09d03 PT	252
	253	if (uid == 0) {
	254	/* Broadcast a shutdown message */
	255	struct kuc_hdr lh;
	256
	257	lh.kuc_magic = KUC_MAGIC;
	258	lh.kuc_transport = KUC_TRANSPORT_GENERIC;
	259	lh.kuc_msgtype = KUC_MSG_SHUTDOWN;
	260	lh.kuc_msglen = sizeof(lh);
	261	libcfs_kkuc_group_put(group, &lh);
	262	}
	263
	264	down_write(&kg_sem);
	265	list_for_each_entry_safe(reg, next, &kkuc_groups[group], kr_chain) {
	266	if ((uid == 0) \|\| (uid == reg->kr_uid)) {
	267	list_del(&reg->kr_chain);
	268	CDEBUG(D_KUC, "Removed uid=%d fp=%p from group %d\n",
	269	reg->kr_uid, reg->kr_fp, group);
	270	if (reg->kr_fp != NULL)
	271	fput(reg->kr_fp);
	272	kfree(reg);
	273	}
	274	}
	275	up_write(&kg_sem);
	276
0a3bdb00	277	return 0;
d7e09d03 PT	278	}
	279	EXPORT_SYMBOL(libcfs_kkuc_group_rem);
	280
	281	int libcfs_kkuc_group_put(int group, void *payload)
	282	{
	283	struct kkuc_reg *reg;
	284	int rc = 0;
	285	int one_success = 0;
d7e09d03 PT	286
	287	down_read(&kg_sem);
	288	list_for_each_entry(reg, &kkuc_groups[group], kr_chain) {
	289	if (reg->kr_fp != NULL) {
	290	rc = libcfs_kkuc_msg_put(reg->kr_fp, payload);
	291	if (rc == 0)
	292	one_success = 1;
	293	else if (rc == -EPIPE) {
	294	fput(reg->kr_fp);
	295	reg->kr_fp = NULL;
	296	}
	297	}
	298	}
	299	up_read(&kg_sem);
	300
	301	/* don't return an error if the message has been delivered
	302	* at least to one agent */
	303	if (one_success)
	304	rc = 0;
	305
0a3bdb00	306	return rc;
d7e09d03 PT	307	}
	308	EXPORT_SYMBOL(libcfs_kkuc_group_put);
	309
	310	/**
	311	* Calls a callback function for each link of the given kuc group.
	312	* @param group the group to call the function on.
	313	* @param cb_func the function to be called.
	314	* @param cb_arg iextra argument to be passed to the callback function.
	315	*/
	316	int libcfs_kkuc_group_foreach(int group, libcfs_kkuc_cb_t cb_func,
	317	void *cb_arg)
	318	{
	319	struct kkuc_reg *reg;
	320	int rc = 0;
d7e09d03 PT	321
	322	if (group > KUC_GRP_MAX) {
	323	CDEBUG(D_WARNING, "Kernelcomm: bad group %d\n", group);
0a3bdb00	324	return -EINVAL;
d7e09d03 PT	325	}
	326
	327	/* no link for this group */
	328	if (kkuc_groups[group].next == NULL)
0a3bdb00	329	return 0;
d7e09d03 PT	330
	331	down_read(&kg_sem);
	332	list_for_each_entry(reg, &kkuc_groups[group], kr_chain) {
	333	if (reg->kr_fp != NULL) {
	334	rc = cb_func(reg->kr_data, cb_arg);
	335	}
	336	}
	337	up_read(&kg_sem);
	338
0a3bdb00	339	return rc;
d7e09d03 PT	340	}
	341	EXPORT_SYMBOL(libcfs_kkuc_group_foreach);
	342
	343	#endif /* LUSTRE_UTILS */