drivers/staging/lustre/lustre/libcfs/kernel_user_comm.c - kernel/lockdown - Git at Google

 /*
  * 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 registration 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 identifier 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 */
	/*
	* 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 registration 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 identifier 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 */