From 7b7bce65bcec3d9aa0be7601d342226a1b534a79 Mon Sep 17 00:00:00 2001 From: Ian Moffett Date: Wed, 1 Oct 2025 14:08:54 -0400 Subject: kern: lib: Introduce pointer boxes Pointer boxes are a way to allocate memory and associate them with one location so that during error/exit paths, one may deallocate every buffer with a single call Signed-off-by: Ian Moffett --- src/sys/include/lib/ptrbox.h | 99 ++++++++++++++++++++++++++++++++++++ src/sys/lib/ptrbox.c | 118 +++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 217 insertions(+) create mode 100644 src/sys/include/lib/ptrbox.h create mode 100644 src/sys/lib/ptrbox.c (limited to 'src') diff --git a/src/sys/include/lib/ptrbox.h b/src/sys/include/lib/ptrbox.h new file mode 100644 index 0000000..a84a760 --- /dev/null +++ b/src/sys/include/lib/ptrbox.h @@ -0,0 +1,99 @@ +/* + * Copyright (c) 2025 Ian Marco Moffett and L5 engineers + * All rights reserved. + * + * 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. + * 3. Neither the name of the project 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 OWNER 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 _PTRBOX_H_ +#define _PTRBOX_H_ 1 + +#include + +struct ptrbox_entry; +struct ptrbox; + +/* + * Represents an allocate entry within a + * pointer box + * + * @data: Allocated data + * @len: Length of allocated data + * @link: Queue link + */ +struct ptrbox_entry { + void *data; + size_t len; + TAILQ_ENTRY(ptrbox_entry) link; +}; + +/* + * Represents a RAII styled pointer box + * + * @count: Number of entries + * @q: Entry queue + * + * Memory is allocated and placed into a pointer + * box + * + * Why?: One call to free them all + */ +struct ptrbox { + size_t count; + TAILQ_HEAD(, ptrbox_entry) q; +}; + +/* + * Initialize a new pointer box + * + * @box_res: Pointer box is written here + * + * Returns zero on success, otherwise a less than + * zero value on failure + */ +int ptrbox_init(struct ptrbox **box_res); + +/* + * Terminate the box from its life and kill its + * children. Used for RAII-styled cleanups. + * + * Returns zero on success, otherwise a less than + * zero value on failure. + */ +int ptrbox_terminate(struct ptrbox *box); + +/* + * Allocate memory and put it into a pointer + * box for RAII style handling + * + * @len: Length of memory to allocate + * @box: Pointer box to use + * + * Returns the allocated memory base on success, otherwise + * a value of NULL on failure. + */ +void *ptrbox_alloc(size_t len, struct ptrbox *box); + +#endif /* !_PTRBOX_H_ */ diff --git a/src/sys/lib/ptrbox.c b/src/sys/lib/ptrbox.c new file mode 100644 index 0000000..b8370e5 --- /dev/null +++ b/src/sys/lib/ptrbox.c @@ -0,0 +1,118 @@ +/* + * Copyright (c) 2025 Ian Marco Moffett and L5 engineers + * All rights reserved. + * + * 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. + * 3. Neither the name of the project 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 OWNER 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 +#include +#include +#include +#include + +/* + * Allocate memory and add it to an existing + * box + */ +void * +ptrbox_alloc(size_t len, struct ptrbox *box) +{ + struct ptrbox_entry *ent; + + if (len == 0 || box == NULL) { + return NULL; + } + + ent = kalloc(sizeof(*ent)); + if (ent == NULL) { + return NULL; + } + + /* Allocate the actual data */ + ent->data = kalloc(len); + if (ent->data == NULL) { + kfree(ent); + return NULL; + } + + ent->len = len; + TAILQ_INSERT_TAIL(&box->q, ent, link); + return ent->data; +} + +/* + * Terminate a box + */ +int +ptrbox_terminate(struct ptrbox *box) +{ + struct ptrbox_entry *ent; + + if (box == NULL) { + return -EINVAL; + } + + /* + * Go through each entry first, reap one + * by one. + */ + TAILQ_FOREACH(ent, &box->q, link) { + if (ent == NULL) { + continue; + } + + kfree(ent->data); + printf("reaped %p\n", ent->data); + ent->data = NULL; + } + + /* Reap ourselves */ + kfree(ent); + return 0; +} + +/* + * Initialize a box + */ +int +ptrbox_init(struct ptrbox **box_res) +{ + struct ptrbox *box; + + if (box_res == NULL) { + return -EINVAL; + } + + box = kalloc(sizeof(*box)); + if (box == NULL) { + return -ENOMEM; + } + + box->count = 0; + TAILQ_INIT(&box->q); + *box_res = box; + return 0; +} -- cgit v1.2.3