/*
* CDDL HEADER START
*
* The contents of this file are subject to the terms of the
* Common Development and Distribution License, Version 1.0 only
* (the "License"). You may not use this file except in compliance
* with the License.
*
* You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
* or http://www.opensolaris.org/os/licensing.
* See the License for the specific language governing permissions
* and limitations under the License.
*
* When distributing Covered Code, include this CDDL HEADER in each
* file and include the License file at usr/src/OPENSOLARIS.LICENSE.
* If applicable, add the following below this CDDL HEADER, with the
* fields enclosed by brackets "[]" replaced with your own identifying
* information: Portions Copyright [yyyy] [name of copyright owner]
*
* CDDL HEADER END
*/
/*
* Copyright 2005 Sun Microsystems, Inc. All rights reserved.
* Use is subject to license terms.
*/
#pragma ident "%Z%%M% %I% %E% SMI"
#include <stdio.h>
#include <fcntl.h>
#include <errno.h>
#include <door.h>
#include <unistd.h>
#include <stddef.h>
#include <stdlib.h>
#include <string.h>
#include <strings.h>
#include <synch.h>
#include <sys/stat.h>
#include <librcm_impl.h>
#include "librcm_event.h"
#define dprint if (debug) (void) printf
static int debug = 1;
#define BUF_THRESHOLD 1024 /* larger bufs require a free */
/*
* Lookup seq_num. We can not use the standard nvlist_lookup functions since
* the nvlist is not allocated with NV_UNIQUE_NAME or NV_UNIQUE_NAME_TYPE.
*/
static int
lookup_seq_num(nvlist_t *nvl, uint64_t *seq_num)
{
nvpair_t *nvp = NULL;
while ((nvp = nvlist_next_nvpair(nvl, nvp)) != NULL) {
if (strcmp(nvpair_name(nvp), RCM_SEQ_NUM) == 0 &&
nvpair_type(nvp) == DATA_TYPE_UINT64)
return (nvpair_value_uint64(nvp, seq_num));
}
return (ENOENT);
}
/*
* Get event service from a named door.
*
* This is similar to sysevent_post_event(), except that it deals with
* the "return buffer problem":
* Typically, the door service places the return buffer on the stack
* when calling door_return(). This places an artificial limit on the
* size of the return buffer.
* This problem is solved by placing large buffers on the heap, referenced
* through door_info. When client detects a large buffer, it will make a
* second door_call() to free the buffer. The client and the server agrees
* on a size, which is defined as BUF_THRESHOLD.
*
* Returns -1 if message not delivered. With errno set to cause of error.
* Returns 0 for success with the results returned in posting buffer.
*/
int
get_event_service(char *door_name, void *data, size_t datalen,
void **result, size_t *rlen)
{
int service_door, error;
door_arg_t door_arg;
/*
* Open the service door
*/
if ((service_door = open(door_name, O_RDONLY, 0)) == -1) {
errno = ESRCH;
return (-1);
}
retry1:
door_arg.rbuf = NULL; /* doorfs will provide return buf */
door_arg.rsize = 0;
door_arg.data_ptr = data;
door_arg.data_size = datalen;
door_arg.desc_ptr = NULL;
door_arg.desc_num = 0;
/*
* Make door call
* EAGAIN is returned when the door server is temporarily
* out of threads to service the door call. So retry.
*/
if ((error = door_call(service_door, &door_arg)) == -1 &&
errno == EAGAIN) {
(void) sleep(1);
goto retry1;
}
if ((error == 0) && result) {
uint64_t seq_num = 0;
*result = NULL;
*rlen = 0;
if (door_arg.rbuf == NULL || door_arg.rsize == 0) {
dprint("bad return from door call\n");
(void) close(service_door);
errno = EFAULT;
return (-1);
}
(void) nvlist_unpack(door_arg.rbuf, door_arg.rsize,
(nvlist_t **)result, 0);
(void) munmap(door_arg.rbuf, door_arg.rsize);
/*
* If requiring a buf free, make another door call. There is
* no need to call munmap() after this door call, though.
*/
if (lookup_seq_num((nvlist_t *)*result, &seq_num) == 0) {
retry2:
door_arg.rbuf = NULL;
door_arg.rsize = 0;
door_arg.data_ptr = (char *)&seq_num;
door_arg.data_size = sizeof (seq_num);
door_arg.desc_ptr = NULL;
door_arg.desc_num = 0;
if (door_call(service_door, &door_arg) == -1) {
if (errno == EAGAIN) {
(void) sleep(1);
goto retry2;
}
dprint("fail to free event buf in server\n");
}
}
}
(void) close(service_door);
return (error);
}
/*
* Export an event service door
*/
struct door_result {
struct door_result *next;
void *data;
uint64_t seq_num;
};
typedef struct door_cookie {
uint64_t seq_num;
mutex_t door_lock;
void (*door_func)(void **, size_t *);
struct door_result *results;
} door_cookie_t;
/*
* add result to cookie, this is only invoked if result size > BUF_THRESHOLD
*/
static void
add_door_result(door_cookie_t *cook, void *data, uint64_t seq_num)
{
struct door_result *result;
/*
* Need a better way to handle memory here
*/
result = malloc(sizeof (*result));
while (result == NULL) {
(void) sleep(1);
result = malloc(sizeof (*result));
}
result->next = NULL;
result->data = data;
result->seq_num = seq_num;
/*
* Attach current door result to the door cookie
*/
(void) mutex_lock(&cook->door_lock);
if (cook->results == NULL) {
cook->results = result;
} else {
struct door_result *tmp = cook->results;
while (tmp->next) {
tmp = tmp->next;
}
tmp->next = result;
}
(void) mutex_unlock(&cook->door_lock);
}
/*
* free a previous door result as described by number.
*/
static void
free_door_result(door_cookie_t *cook, uint64_t num)
{
struct door_result *prev = NULL, *tmp;
(void) mutex_lock(&cook->door_lock);
tmp = cook->results;
while (tmp && tmp->seq_num != num) {
prev = tmp;
tmp = tmp->next;
}
if (tmp == NULL) {
dprint("attempting to free nonexistent buf: %llu\n",
(unsigned long long)num);
(void) mutex_unlock(&cook->door_lock);
return;
}
if (prev) {
prev->next = tmp->next;
} else {
cook->results = tmp->next;
}
(void) mutex_unlock(&cook->door_lock);
free(tmp->data);
free(tmp);
}
/*ARGSUSED*/
static void
door_service(void *cookie, char *args, size_t alen,
door_desc_t *ddp, uint_t ndid)
{
nvlist_t *nvl;
size_t nvl_size = 0;
char rbuf[BUF_THRESHOLD];
door_cookie_t *cook = (door_cookie_t *)cookie;
uint64_t seq_num = 0;
/*
* Special case for asking to free buffer
*/
if (alen == sizeof (uint64_t)) {
free_door_result(cookie, *(uint64_t *)(void *)args);
(void) door_return(NULL, 0, NULL, 0);
}
/*
* door_func update args to point to return results.
* memory for results are dynamically allocated.
*/
(*cook->door_func)((void **)&args, &alen);
/*
* If no results, just return
*/
if (args == NULL) {
dprint("null results returned from door_func().\n");
(void) door_return(NULL, 0, NULL, 0);
}
/* Determine the size of the packed nvlist */
nvl = (nvlist_t *)(void *)args;
args = NULL;
alen = 0;
if (errno = nvlist_size(nvl, &nvl_size, NV_ENCODE_NATIVE)) {
nvlist_free(nvl);
dprint("failure to sizeup door results: %s\n", strerror(errno));
(void) door_return(NULL, 0, NULL, 0);
}
/*
* If the size of the packed nvlist would exceed the buffer threshold
* then get a sequence number and add it to the nvlist.
*/
if (nvl_size > BUF_THRESHOLD) {
(void) mutex_lock(&cook->door_lock);
cook->seq_num++;
seq_num = cook->seq_num;
(void) mutex_unlock(&cook->door_lock);
(void) nvlist_add_uint64(nvl, RCM_SEQ_NUM, seq_num);
}
/* Refill the args with a packed version of the nvlist */
if (errno = nvlist_pack(nvl, &args, &alen, NV_ENCODE_NATIVE, 0)) {
nvlist_free(nvl);
dprint("failure to pack door results: %s\n", strerror(errno));
(void) door_return(NULL, 0, NULL, 0);
}
nvlist_free(nvl);
/*
* Based on the size of the packed nvlist, either use the local buffer
* or add it to the results list.
*/
if (alen <= BUF_THRESHOLD) {
bcopy(args, rbuf, alen);
(void) free(args);
args = rbuf;
} else {
/*
* for long data, append results to end of queue in cook
* and set ndid, ask client to do another door_call
* to free the buffer.
*/
add_door_result(cook, args, seq_num);
}
(void) door_return(args, alen, NULL, 0);
}
int
create_event_service(char *door_name,
void (*func)(void **data, size_t *datalen))
{
int service_door, fd;
door_cookie_t *cookie;
/* create an fs file */
fd = open(door_name, O_EXCL|O_CREAT, S_IREAD|S_IWRITE);
if ((fd == -1) && (errno != EEXIST)) {
return (-1);
}
(void) close(fd);
/* allocate space for door cookie */
if ((cookie = calloc(1, sizeof (*cookie))) == NULL) {
return (-1);
}
cookie->door_func = func;
if ((service_door = door_create(door_service, (void *)cookie,
DOOR_REFUSE_DESC | DOOR_NO_CANCEL)) == -1) {
dprint("door create failed: %s\n", strerror(errno));
free(cookie);
return (-1);
}
retry:
(void) fdetach(door_name);
if (fattach(service_door, door_name) != 0) {
if (errno == EBUSY) {
/*
* EBUSY error may occur if anyone references the door
* file while we are fattach'ing. Since librcm, in the
* the process context of a DR initiator program, may
* reference the door file (via open/close/stat/
* door_call etc.) while we are still fattach'ing,
* retry on EBUSY.
*/
goto retry;
}
dprint("door attaching failed: %s\n", strerror(errno));
free(cookie);
(void) close(service_door);
return (-1);
}
return (service_door);
}
int
revoke_event_service(int fd)
{
struct door_info info;
door_cookie_t *cookie;
if (door_info(fd, &info) == -1) {
return (-1);
}
if (door_revoke(fd) != 0) {
return (-1);
}
/* wait for existing door calls to finish */
(void) sleep(1);
if ((cookie = (door_cookie_t *)(uintptr_t)info.di_data) != NULL) {
struct door_result *tmp = cookie->results;
while (tmp) {
cookie->results = tmp->next;
free(tmp->data);
free(tmp);
tmp = cookie->results;
}
free(cookie);
}
return (0);
}