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/*
* debug.h -- debugging routines for libtirpc
*
* Copyright (c) 2020 SUSE LINUX GmbH, Nuernberg, Germany.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions are met:
* - Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* - Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
* - Neither the name of Sun Microsystems, Inc. nor the names of its
* contributors may be used to endorse or promote products derived
* from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef _CLNT_FD_LOCKS_H
#define _CLNT_FD_LOCKS_H
#include <sys/queue.h>
#include <errno.h>
#include <reentrant.h>
#include <rpc/xdr.h>
/*
* This utility manages a list of per-fd locks for the clients.
*
* If MAX_FDLOCKS_PREALLOC is defined, a number of pre-fd locks will be
* pre-allocated. This number is the minimum of MAX_FDLOCKS_PREALLOC or
* the process soft limit of allowed fds.
*/
#ifdef MAX_FDLOCKS_PREALLOC
static unsigned int fd_locks_prealloc = 0;
#endif
/* per-fd lock */
struct fd_lock_t {
bool_t active;
int pending; /* Number of pending operations on fd */
cond_t cv;
};
typedef struct fd_lock_t fd_lock_t;
/* internal type to store per-fd locks in a list */
struct fd_lock_item_t {
/* fd_lock_t first so we can cast to fd_lock_item_t */
fd_lock_t fd_lock;
int fd;
unsigned int refs;
TAILQ_ENTRY(fd_lock_item_t) link;
};
typedef struct fd_lock_item_t fd_lock_item_t;
#define to_fd_lock_item(fdlock_t_ptr) ((fd_lock_item_t*) fdlock_t_ptr)
/* internal list of per-fd locks */
typedef TAILQ_HEAD(,fd_lock_item_t) fd_lock_list_t;
#ifdef MAX_FDLOCKS_PREALLOC
/* With pre-allocation, keep track of both an array and a list */
struct fd_locks_t {
fd_lock_list_t fd_lock_list;
fd_lock_t *fd_lock_array;
};
typedef struct fd_locks_t fd_locks_t;
#define to_fd_lock_list(fd_locks_t_ptr) (&fd_locks_t_ptr->fd_lock_list)
#else
/* With no pre-allocation, just keep track of a list */
typedef fd_lock_list_t fd_locks_t;
#define to_fd_lock_list(fd_locks_t_ptr) ((fd_lock_list_t *) fd_locks_t_ptr)
#endif
/* allocate fd locks */
static inline
fd_locks_t* fd_locks_init() {
fd_locks_t *fd_locks;
fd_locks = (fd_locks_t *) mem_alloc(sizeof(fd_locks_t));
if (fd_locks == (fd_locks_t *) NULL) {
errno = ENOMEM;
return (NULL);
}
TAILQ_INIT(to_fd_lock_list(fd_locks));
#ifdef MAX_FDLOCKS_PREALLOC
size_t fd_lock_arraysz;
if (fd_locks_prealloc == 0) {
unsigned int dtbsize = __rpc_dtbsize();
if (0 < dtbsize && dtbsize < MAX_FDLOCKS_PREALLOC)
fd_locks_prealloc = dtbsize;
else
fd_locks_prealloc = MAX_FDLOCKS_PREALLOC;
}
if ( (size_t) fd_locks_prealloc > SIZE_MAX/sizeof(fd_lock_t)) {
mem_free(fd_locks, sizeof (*fd_locks));
errno = EOVERFLOW;
return (NULL);
}
fd_lock_arraysz = fd_locks_prealloc * sizeof (fd_lock_t);
fd_locks->fd_lock_array = (fd_lock_t *) mem_alloc(fd_lock_arraysz);
if (fd_locks->fd_lock_array == (fd_lock_t *) NULL) {
mem_free(fd_locks, sizeof (*fd_locks));
errno = ENOMEM;
return (NULL);
}
else {
int i;
for (i = 0; i < fd_locks_prealloc; i++) {
fd_locks->fd_lock_array[i].active = FALSE;
cond_init(&fd_locks->fd_lock_array[i].cv, 0, (void *) 0);
}
}
#endif
return fd_locks;
}
/* de-allocate fd locks */
static inline
void fd_locks_destroy(fd_locks_t *fd_locks) {
#ifdef MAX_FDLOCKS_PREALLOC
fd_lock_t *array = fd_locks->fd_lock_array;
mem_free(array, fd_locks_prealloc * sizeof (fd_lock_t));
#endif
fd_lock_item_t *item;
fd_lock_list_t *list = to_fd_lock_list(fd_locks);
TAILQ_FOREACH(item, list, link) {
cond_destroy(&item->fd_lock.cv);
mem_free(item, sizeof (*item));
}
mem_free(fd_locks, sizeof (*fd_locks));
}
/* allocate per-fd lock */
static inline
fd_lock_t* fd_lock_create(int fd, fd_locks_t *fd_locks) {
#ifdef MAX_FDLOCKS_PREALLOC
if (fd < fd_locks_prealloc) {
return &fd_locks->fd_lock_array[fd];
}
#endif
fd_lock_item_t *item;
fd_lock_list_t *list = to_fd_lock_list(fd_locks);
for (item = TAILQ_FIRST(list);
item != (fd_lock_item_t *) NULL && item->fd != fd;
item = TAILQ_NEXT(item, link));
if (item == (fd_lock_item_t *) NULL) {
item = (fd_lock_item_t *) mem_alloc(sizeof(fd_lock_item_t));
if (item == (fd_lock_item_t *) NULL) {
errno = ENOMEM;
return (NULL);
}
item->fd = fd;
item->refs = 1;
item->fd_lock.active = FALSE;
item->fd_lock.pending = 0;
cond_init(&item->fd_lock.cv, 0, (void *) 0);
TAILQ_INSERT_HEAD(list, item, link);
} else {
item->refs++;
}
return &item->fd_lock;
}
/* de-allocate per-fd lock */
static inline
void fd_lock_destroy(int fd, fd_lock_t *fd_lock, fd_locks_t *fd_locks) {
#ifdef MAX_FDLOCKS_PREALLOC
if (fd < fd_locks_prealloc)
return;
#endif
fd_lock_item_t* item = to_fd_lock_item(fd_lock);
item->refs--;
if (item->refs <= 0) {
TAILQ_REMOVE(to_fd_lock_list(fd_locks), item, link);
cond_destroy(&item->fd_lock.cv);
mem_free(item, sizeof (*item));
}
}
#endif /* _CLNT_FD_LOCKS_H */
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