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Diffstat (limited to 'src/clnt_fd_locks.h')
| -rw-r--r-- | src/clnt_fd_locks.h | 209 |
1 files changed, 209 insertions, 0 deletions
diff --git a/src/clnt_fd_locks.h b/src/clnt_fd_locks.h new file mode 100644 index 0000000..6ba62cb --- /dev/null +++ b/src/clnt_fd_locks.h @@ -0,0 +1,209 @@ +/* + * 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 */ |