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665b8e5283
To avoid byzantine behavior in case of some errors, linked lists are cleared after rem_node() and resource headers are cleared after rfree().
427 lines
8.4 KiB
C
427 lines
8.4 KiB
C
/*
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* BIRD Resource Manager
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*
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* (c) 1998--2000 Martin Mares <mj@ucw.cz>
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*
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* Can be freely distributed and used under the terms of the GNU GPL.
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include <stdint.h>
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#include "nest/bird.h"
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#include "lib/resource.h"
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#include "lib/string.h"
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/**
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* DOC: Resource pools
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*
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* Resource pools (&pool) are just containers holding a list of
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* other resources. Freeing a pool causes all the listed resources
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* to be freed as well. Each existing &resource is linked to some pool
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* except for a root pool which isn't linked anywhere, so all the
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* resources form a tree structure with internal nodes corresponding
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* to pools and leaves being the other resources.
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*
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* Example: Almost all modules of BIRD have their private pool which
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* is freed upon shutdown of the module.
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*/
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struct pool {
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resource r;
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list inside;
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char *name;
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};
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static void pool_dump(resource *);
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static void pool_free(resource *);
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static resource *pool_lookup(resource *, unsigned long);
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static size_t pool_memsize(resource *P);
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static struct resclass pool_class = {
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"Pool",
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sizeof(pool),
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pool_free,
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pool_dump,
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pool_lookup,
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pool_memsize
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};
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pool root_pool;
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static int indent;
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/**
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* rp_new - create a resource pool
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* @p: parent pool
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* @name: pool name (to be included in debugging dumps)
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*
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* rp_new() creates a new resource pool inside the specified
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* parent pool.
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*/
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pool *
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rp_new(pool *p, char *name)
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{
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pool *z = ralloc(p, &pool_class);
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z->name = name;
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init_list(&z->inside);
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return z;
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}
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static void
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pool_free(resource *P)
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{
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pool *p = (pool *) P;
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resource *r, *rr;
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r = HEAD(p->inside);
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while (rr = (resource *) r->n.next)
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{
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r->class->free(r);
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xfree(r);
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r = rr;
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}
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}
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static void
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pool_dump(resource *P)
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{
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pool *p = (pool *) P;
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resource *r;
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debug("%s\n", p->name);
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indent += 3;
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WALK_LIST(r, p->inside)
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rdump(r);
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indent -= 3;
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}
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static size_t
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pool_memsize(resource *P)
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{
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pool *p = (pool *) P;
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resource *r;
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size_t sum = sizeof(pool) + ALLOC_OVERHEAD;
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WALK_LIST(r, p->inside)
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sum += rmemsize(r);
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return sum;
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}
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static resource *
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pool_lookup(resource *P, unsigned long a)
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{
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pool *p = (pool *) P;
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resource *r, *q;
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WALK_LIST(r, p->inside)
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if (r->class->lookup && (q = r->class->lookup(r, a)))
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return q;
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return NULL;
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}
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/**
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* rmove - move a resource
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* @res: resource
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* @p: pool to move the resource to
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*
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* rmove() moves a resource from one pool to another.
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*/
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void rmove(void *res, pool *p)
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{
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resource *r = res;
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if (r)
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{
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if (r->n.next)
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rem_node(&r->n);
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add_tail(&p->inside, &r->n);
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}
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}
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/**
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* rfree - free a resource
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* @res: resource
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*
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* rfree() frees the given resource and all information associated
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* with it. In case it's a resource pool, it also frees all the objects
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* living inside the pool.
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*
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* It works by calling a class-specific freeing function.
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*/
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void
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rfree(void *res)
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{
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resource *r = res;
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if (!r)
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return;
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if (r->n.next)
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rem_node(&r->n);
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r->class->free(r);
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r->class = NULL;
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xfree(r);
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}
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/**
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* rdump - dump a resource
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* @res: resource
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*
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* This function prints out all available information about the given
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* resource to the debugging output.
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*
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* It works by calling a class-specific dump function.
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*/
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void
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rdump(void *res)
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{
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char x[16];
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resource *r = res;
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bsprintf(x, "%%%ds%%p ", indent);
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debug(x, "", r);
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if (r)
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{
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debug("%s ", r->class->name);
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r->class->dump(r);
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}
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else
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debug("NULL\n");
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}
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size_t
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rmemsize(void *res)
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{
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resource *r = res;
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if (!r)
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return 0;
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if (!r->class->memsize)
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return r->class->size + ALLOC_OVERHEAD;
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return r->class->memsize(r);
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}
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/**
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* ralloc - create a resource
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* @p: pool to create the resource in
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* @c: class of the new resource
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*
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* This function is called by the resource classes to create a new
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* resource of the specified class and link it to the given pool.
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* Allocated memory is zeroed. Size of the resource structure is taken
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* from the @size field of the &resclass.
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*/
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void *
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ralloc(pool *p, struct resclass *c)
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{
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resource *r = xmalloc(c->size);
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bzero(r, c->size);
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r->class = c;
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if (p)
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add_tail(&p->inside, &r->n);
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return r;
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}
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/**
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* rlookup - look up a memory location
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* @a: memory address
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*
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* This function examines all existing resources to see whether
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* the address @a is inside any resource. It's used for debugging
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* purposes only.
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*
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* It works by calling a class-specific lookup function for each
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* resource.
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*/
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void
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rlookup(unsigned long a)
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{
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resource *r;
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debug("Looking up %08lx\n", a);
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if (r = pool_lookup(&root_pool.r, a))
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rdump(r);
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else
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debug("Not found.\n");
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}
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/**
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* resource_init - initialize the resource manager
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*
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* This function is called during BIRD startup. It initializes
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* all data structures of the resource manager and creates the
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* root pool.
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*/
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void
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resource_init(void)
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{
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root_pool.r.class = &pool_class;
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root_pool.name = "Root";
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init_list(&root_pool.inside);
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}
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/**
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* DOC: Memory blocks
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*
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* Memory blocks are pieces of contiguous allocated memory.
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* They are a bit non-standard since they are represented not by a pointer
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* to &resource, but by a void pointer to the start of data of the
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* memory block. All memory block functions know how to locate the header
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* given the data pointer.
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*
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* Example: All "unique" data structures such as hash tables are allocated
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* as memory blocks.
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*/
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struct mblock {
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resource r;
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unsigned size;
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uintptr_t data_align[0];
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byte data[0];
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};
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static void mbl_free(resource *r UNUSED)
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{
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}
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static void mbl_debug(resource *r)
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{
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struct mblock *m = (struct mblock *) r;
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debug("(size=%d)\n", m->size);
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}
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static resource *
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mbl_lookup(resource *r, unsigned long a)
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{
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struct mblock *m = (struct mblock *) r;
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if ((unsigned long) m->data <= a && (unsigned long) m->data + m->size > a)
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return r;
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return NULL;
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}
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static size_t
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mbl_memsize(resource *r)
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{
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struct mblock *m = (struct mblock *) r;
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return ALLOC_OVERHEAD + sizeof(struct mblock) + m->size;
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}
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static struct resclass mb_class = {
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"Memory",
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0,
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mbl_free,
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mbl_debug,
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mbl_lookup,
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mbl_memsize
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};
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/**
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* mb_alloc - allocate a memory block
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* @p: pool
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* @size: size of the block
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*
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* mb_alloc() allocates memory of a given size and creates
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* a memory block resource representing this memory chunk
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* in the pool @p.
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*
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* Please note that mb_alloc() returns a pointer to the memory
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* chunk, not to the resource, hence you have to free it using
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* mb_free(), not rfree().
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*/
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void *
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mb_alloc(pool *p, unsigned size)
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{
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struct mblock *b = xmalloc(sizeof(struct mblock) + size);
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b->r.class = &mb_class;
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add_tail(&p->inside, &b->r.n);
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b->size = size;
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return b->data;
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}
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/**
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* mb_allocz - allocate and clear a memory block
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* @p: pool
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* @size: size of the block
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*
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* mb_allocz() allocates memory of a given size, initializes it to
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* zeroes and creates a memory block resource representing this memory
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* chunk in the pool @p.
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*
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* Please note that mb_allocz() returns a pointer to the memory
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* chunk, not to the resource, hence you have to free it using
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* mb_free(), not rfree().
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*/
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void *
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mb_allocz(pool *p, unsigned size)
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{
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void *x = mb_alloc(p, size);
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bzero(x, size);
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return x;
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}
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/**
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* mb_realloc - reallocate a memory block
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* @m: memory block
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* @size: new size of the block
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*
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* mb_realloc() changes the size of the memory block @m to a given size.
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* The contents will be unchanged to the minimum of the old and new sizes;
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* newly allocated memory will be uninitialized. Contrary to realloc()
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* behavior, @m must be non-NULL, because the resource pool is inherited
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* from it.
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*
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* Like mb_alloc(), mb_realloc() also returns a pointer to the memory
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* chunk, not to the resource, hence you have to free it using
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* mb_free(), not rfree().
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*/
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void *
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mb_realloc(void *m, unsigned size)
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{
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struct mblock *b = SKIP_BACK(struct mblock, data, m);
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b = xrealloc(b, sizeof(struct mblock) + size);
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replace_node(&b->r.n, &b->r.n);
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b->size = size;
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return b->data;
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}
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/**
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* mb_free - free a memory block
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* @m: memory block
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*
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* mb_free() frees all memory associated with the block @m.
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*/
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void
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mb_free(void *m)
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{
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if (!m)
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return;
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struct mblock *b = SKIP_BACK(struct mblock, data, m);
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rfree(b);
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}
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#define STEP_UP(x) ((x) + (x)/2 + 4)
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void
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buffer_realloc(void **buf, unsigned *size, unsigned need, unsigned item_size)
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{
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unsigned nsize = MIN(*size, need);
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while (nsize < need)
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nsize = STEP_UP(nsize);
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*buf = mb_realloc(*buf, nsize * item_size);
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*size = nsize;
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}
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