/* * BIRD Resource Manager * * (c) 1998--2000 Martin Mares <mj@ucw.cz> * * Can be freely distributed and used under the terms of the GNU GPL. */ #include <stdio.h> #include <stdlib.h> #include <stdint.h> #include "nest/bird.h" #include "lib/resource.h" #include "lib/string.h" /** * DOC: Resource pools * * Resource pools (&pool) are just containers holding a list of * other resources. Freeing a pool causes all the listed resources * to be freed as well. Each existing &resource is linked to some pool * except for a root pool which isn't linked anywhere, so all the * resources form a tree structure with internal nodes corresponding * to pools and leaves being the other resources. * * Example: Almost all modules of BIRD have their private pool which * is freed upon shutdown of the module. */ struct pool { resource r; list inside; char *name; }; static void pool_dump(resource *); static void pool_free(resource *); static resource *pool_lookup(resource *, unsigned long); static struct resclass pool_class = { "Pool", sizeof(pool), pool_free, pool_dump, pool_lookup }; pool root_pool; static int indent; /** * rp_new - create a resource pool * @p: parent pool * @name: pool name (to be included in debugging dumps) * * rp_new() creates a new resource pool inside the specified * parent pool. */ pool * rp_new(pool *p, char *name) { pool *z = ralloc(p, &pool_class); z->name = name; init_list(&z->inside); return z; } static void pool_free(resource *P) { pool *p = (pool *) P; resource *r, *rr; r = HEAD(p->inside); while (rr = (resource *) r->n.next) { r->class->free(r); xfree(r); r = rr; } } static void pool_dump(resource *P) { pool *p = (pool *) P; resource *r; debug("%s\n", p->name); indent += 3; WALK_LIST(r, p->inside) rdump(r); indent -= 3; } static resource * pool_lookup(resource *P, unsigned long a) { pool *p = (pool *) P; resource *r, *q; WALK_LIST(r, p->inside) if (r->class->lookup && (q = r->class->lookup(r, a))) return q; return NULL; } /** * rmove - move a resource * @res: resource * @p: pool to move the resource to * * rmove() moves a resource from one pool to another. */ void rmove(void *res, pool *p) { resource *r = res; if (r) { if (r->n.next) rem_node(&r->n); add_tail(&p->inside, &r->n); } } /** * rfree - free a resource * @res: resource * * rfree() frees the given resource and all information associated * with it. In case it's a resource pool, it also frees all the objects * living inside the pool. * * It works by calling a class-specific freeing function. */ void rfree(void *res) { resource *r = res; if (r) { if (r->n.next) rem_node(&r->n); r->class->free(r); xfree(r); } } /** * rdump - dump a resource * @res: resource * * This function prints out all available information about the given * resource to the debugging output. * * It works by calling a class-specific dump function. */ void rdump(void *res) { char x[16]; resource *r = res; bsprintf(x, "%%%ds%%p ", indent); debug(x, "", r); if (r) { debug("%s ", r->class->name); r->class->dump(r); } else debug("NULL\n"); } /** * ralloc - create a resource * @p: pool to create the resource in * @c: class of the new resource * * This function is called by the resource classes to create a new * resource of the specified class and link it to the given pool. * Allocated memory is zeroed. Size of the resource structure is taken * from the @size field of the &resclass. */ void * ralloc(pool *p, struct resclass *c) { resource *r = xmalloc(c->size); bzero(r, c->size); r->class = c; add_tail(&p->inside, &r->n); return r; } /** * rlookup - look up a memory location * @a: memory address * * This function examines all existing resources to see whether * the address @a is inside any resource. It's used for debugging * purposes only. * * It works by calling a class-specific lookup function for each * resource. */ void rlookup(unsigned long a) { resource *r; debug("Looking up %08lx\n", a); if (r = pool_lookup(&root_pool.r, a)) rdump(r); else debug("Not found.\n"); } /** * resource_init - initialize the resource manager * * This function is called during BIRD startup. It initializes * all data structures of the resource manager and creates the * root pool. */ void resource_init(void) { root_pool.r.class = &pool_class; root_pool.name = "Root"; init_list(&root_pool.inside); } /** * DOC: Memory blocks * * Memory blocks are pieces of contiguous allocated memory. * They are a bit non-standard since they are represented not by a pointer * to &resource, but by a void pointer to the start of data of the * memory block. All memory block functions know how to locate the header * given the data pointer. * * Example: All "unique" data structures such as hash tables are allocated * as memory blocks. */ struct mblock { resource r; unsigned size; uintptr_t data_align[0]; byte data[0]; }; static void mbl_free(resource *r UNUSED) { } static void mbl_debug(resource *r) { struct mblock *m = (struct mblock *) r; debug("(size=%d)\n", m->size); } static resource * mbl_lookup(resource *r, unsigned long a) { struct mblock *m = (struct mblock *) r; if ((unsigned long) m->data <= a && (unsigned long) m->data + m->size > a) return r; return NULL; } static struct resclass mb_class = { "Memory", 0, mbl_free, mbl_debug, mbl_lookup }; /** * mb_alloc - allocate a memory block * @p: pool * @size: size of the block * * mb_alloc() allocates memory of a given size and creates * a memory block resource representing this memory chunk * in the pool @p. * * Please note that mb_alloc() returns a pointer to the memory * chunk, not to the resource, hence you have to free it using * mb_free(), not rfree(). */ void * mb_alloc(pool *p, unsigned size) { struct mblock *b = xmalloc(sizeof(struct mblock) + size); b->r.class = &mb_class; add_tail(&p->inside, &b->r.n); b->size = size; return b->data; } /** * mb_allocz - allocate and clear a memory block * @p: pool * @size: size of the block * * mb_allocz() allocates memory of a given size, initializes it to * zeroes and creates a memory block resource representing this memory * chunk in the pool @p. * * Please note that mb_alloc() returns a pointer to the memory * chunk, not to the resource, hence you have to free it using * mb_free(), not rfree(). */ void * mb_allocz(pool *p, unsigned size) { void *x = mb_alloc(p, size); bzero(x, size); return x; } /** * mb_realloc - reallocate a memory block * @p: pool * @m: memory block * @size: new size of the block * * mb_realloc() changes the size of the memory block @m to a given size. * The contents will be unchanged to the minimum of the old and new sizes; * newly allocated memory will be uninitialized. If @m is NULL, the call * is equivalent to mb_alloc(@p, @size). * * Like mb_alloc(), mb_realloc() also returns a pointer to the memory * chunk , not to the resource, hence you have to free it using * mb_free(), not rfree(). */ void * mb_realloc(pool *p, void *m, unsigned size) { struct mblock *ob = NULL; if (m) { ob = SKIP_BACK(struct mblock, data, m); if (ob->r.n.next) rem_node(&ob->r.n); } struct mblock *b = xrealloc(ob, sizeof(struct mblock) + size); b->r.class = &mb_class; add_tail(&p->inside, &b->r.n); b->size = size; return b->data; } /** * mb_free - free a memory block * @m: memory block * * mb_free() frees all memory associated with the block @m. */ void mb_free(void *m) { struct mblock *b = SKIP_BACK(struct mblock, data, m); rfree(b); }