diff options
Diffstat (limited to 'sbin/hastd/ebuf.c')
| -rw-r--r-- | sbin/hastd/ebuf.c | 252 |
1 files changed, 252 insertions, 0 deletions
diff --git a/sbin/hastd/ebuf.c b/sbin/hastd/ebuf.c new file mode 100644 index 0000000..47b7530 --- /dev/null +++ b/sbin/hastd/ebuf.c @@ -0,0 +1,252 @@ +/*- + * Copyright (c) 2009-2010 The FreeBSD Foundation + * All rights reserved. + * + * This software was developed by Pawel Jakub Dawidek under sponsorship from + * the FreeBSD Foundation. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * 1. Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * 2. 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. + * + * THIS SOFTWARE IS PROVIDED BY THE AUTHORS 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 AUTHORS 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. + */ + +#include <sys/cdefs.h> +__FBSDID("$FreeBSD$"); + +#include <sys/param.h> + +#include <assert.h> +#include <errno.h> +#include <stdbool.h> +#include <stdint.h> +#include <strings.h> +#include <unistd.h> + +#include "ebuf.h" + +#define EBUF_MAGIC 0xeb0f41c +struct ebuf { + /* Magic to assert the caller uses valid structure. */ + int eb_magic; + /* Address where we did the allocation. */ + unsigned char *eb_start; + /* Allocation end address. */ + unsigned char *eb_end; + /* Start of real data. */ + unsigned char *eb_used; + /* Size of real data. */ + size_t eb_size; +}; + +static int ebuf_head_extent(struct ebuf *eb, size_t size); +static int ebuf_tail_extent(struct ebuf *eb, size_t size); + +struct ebuf * +ebuf_alloc(size_t size) +{ + struct ebuf *eb; + int rerrno; + + eb = malloc(sizeof(*eb)); + if (eb == NULL) + return (NULL); + size += PAGE_SIZE; + eb->eb_start = malloc(size); + if (eb->eb_start == NULL) { + rerrno = errno; + free(eb); + errno = rerrno; + return (NULL); + } + eb->eb_end = eb->eb_start + size; + /* + * We set start address for real data not at the first entry, because + * we want to be able to add data at the front. + */ + eb->eb_used = eb->eb_start + PAGE_SIZE / 4; + eb->eb_size = 0; + eb->eb_magic = EBUF_MAGIC; + + return (eb); +} + +void +ebuf_free(struct ebuf *eb) +{ + + assert(eb != NULL && eb->eb_magic == EBUF_MAGIC); + + eb->eb_magic = 0; + + free(eb->eb_start); + free(eb); +} + +int +ebuf_add_head(struct ebuf *eb, const void *data, size_t size) +{ + + assert(eb != NULL && eb->eb_magic == EBUF_MAGIC); + + if (size > (size_t)(eb->eb_used - eb->eb_start)) { + /* + * We can't add more entries at the front, so we have to extend + * our buffer. + */ + if (ebuf_head_extent(eb, size) < 0) + return (-1); + } + assert(size <= (size_t)(eb->eb_used - eb->eb_start)); + + eb->eb_size += size; + eb->eb_used -= size; + /* + * If data is NULL the caller just wants to reserve place. + */ + if (data != NULL) + bcopy(data, eb->eb_used, size); + + return (0); +} + +int +ebuf_add_tail(struct ebuf *eb, const void *data, size_t size) +{ + + assert(eb != NULL && eb->eb_magic == EBUF_MAGIC); + + if (size > (size_t)(eb->eb_end - (eb->eb_used + eb->eb_size))) { + /* + * We can't add more entries at the back, so we have to extend + * our buffer. + */ + if (ebuf_tail_extent(eb, size) < 0) + return (-1); + } + assert(size <= (size_t)(eb->eb_end - (eb->eb_used + eb->eb_size))); + + /* + * If data is NULL the caller just wants to reserve place. + */ + if (data != NULL) + bcopy(data, eb->eb_used + eb->eb_size, size); + eb->eb_size += size; + + return (0); +} + +void +ebuf_del_head(struct ebuf *eb, size_t size) +{ + + assert(eb != NULL && eb->eb_magic == EBUF_MAGIC); + assert(size <= eb->eb_size); + + eb->eb_used += size; + eb->eb_size -= size; +} + +void +ebuf_del_tail(struct ebuf *eb, size_t size) +{ + + assert(eb != NULL && eb->eb_magic == EBUF_MAGIC); + assert(size <= eb->eb_size); + + eb->eb_size -= size; +} + +/* + * Return pointer to the data and data size. + */ +void * +ebuf_data(struct ebuf *eb, size_t *sizep) +{ + + assert(eb != NULL && eb->eb_magic == EBUF_MAGIC); + + if (sizep != NULL) + *sizep = eb->eb_size; + return (eb->eb_size > 0 ? eb->eb_used : NULL); +} + +/* + * Return data size. + */ +size_t +ebuf_size(struct ebuf *eb) +{ + + assert(eb != NULL && eb->eb_magic == EBUF_MAGIC); + + return (eb->eb_size); +} + +/* + * Function adds size + (PAGE_SIZE / 4) bytes at the front of the buffer.. + */ +static int +ebuf_head_extent(struct ebuf *eb, size_t size) +{ + unsigned char *newstart, *newused; + size_t newsize; + + assert(eb != NULL && eb->eb_magic == EBUF_MAGIC); + + newsize = eb->eb_end - eb->eb_start + (PAGE_SIZE / 4) + size; + + newstart = malloc(newsize); + if (newstart == NULL) + return (-1); + newused = + newstart + (PAGE_SIZE / 4) + size + (eb->eb_used - eb->eb_start); + + bcopy(eb->eb_used, newused, eb->eb_size); + + eb->eb_start = newstart; + eb->eb_used = newused; + eb->eb_end = newstart + newsize; + + return (0); +} + +/* + * Function adds size + ((3 * PAGE_SIZE) / 4) bytes at the back. + */ +static int +ebuf_tail_extent(struct ebuf *eb, size_t size) +{ + unsigned char *newstart; + size_t newsize; + + assert(eb != NULL && eb->eb_magic == EBUF_MAGIC); + + newsize = eb->eb_end - eb->eb_start + size + ((3 * PAGE_SIZE) / 4); + + newstart = realloc(eb->eb_start, newsize); + if (newstart == NULL) + return (-1); + + eb->eb_used = newstart + (eb->eb_used - eb->eb_start); + eb->eb_start = newstart; + eb->eb_end = newstart + newsize; + + return (0); +} |
