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* 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(®->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;
ENTRY;
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(®->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;
ENTRY;
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;
ENTRY;
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 */
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