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commit 57cede2e1a4902f3833af79d1330160686c215dd
parent e7299d91751363b8eefe9256f7f5ec86797a4ec9
Author: sin <sin@2f30.org>
Date:   Thu Aug  1 15:04:00 +0100

Only free `oldp' if it is non-NULL

Diffstat:
random/alloc.c | 2+-
random/rballoc.c | 243+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 244 insertions(+), 1 deletion(-)
diff --git a/random/alloc.c b/random/alloc.c @@ -92,7 +92,7 @@ realloc(void *oldp, size_t nbytes) size_t n; long i; - if (!nbytes) { + if (!nbytes && oldp) { free(oldp); return NULL; } diff --git a/random/rballoc.c b/random/rballoc.c @@ -0,0 +1,243 @@ +#include <sys/mman.h> +#include <unistd.h> +#include <stdio.h> +#include <stdlib.h> +#include <string.h> +#include <errno.h> +#include "tree.h" + +enum { PAGESIZE = 4096 }; + +struct node { + void *buf; + size_t siz; + RB_ENTRY(node) entry; +}; + +RB_HEAD(free_tree, node) ft = RB_INITIALIZER(&ft); +RB_HEAD(alloc_tree, node) at = RB_INITIALIZER(&at); + +static int ft_cmp(struct node *a, struct node *b); +RB_PROTOTYPE(free_tree, node, entry, ft_cmp); + +static int at_cmp(struct node *a, struct node *b); +RB_PROTOTYPE(alloc_tree, node, entry, at_cmp); + +RB_GENERATE(free_tree, node, entry, ft_cmp); +/* These are ordered by `siz' */ +static int +ft_cmp(struct node *a, struct node *b) +{ + if (a->siz < b->siz) + return -1; + if (a->siz > b->siz) + return 1; + return 0; +} + +RB_GENERATE(alloc_tree, node, entry, at_cmp); +/* These are ordered by address */ +static int +at_cmp(struct node *a, struct node *b) +{ + if (a->buf < b->buf) + return -1; + if (a->buf > b->buf) + return 1; + return 0; +} + +static void +dump_alloc_tree(void) +{ + struct node *n; + + RB_FOREACH(n, alloc_tree, &at) + fprintf(stderr, "%s: buf: %p, size: %zu\n", + __func__, n->buf, n->siz); +} + +static void +dump_free_tree(void) +{ + struct node *n; + + RB_FOREACH(n, free_tree, &ft) + fprintf(stderr, "%s: buf: %p, size: %zu\n", + __func__, n->buf, n->siz); +} + +static void * +alloc_object(size_t siz) +{ + void *p; + + p = mmap(0, siz, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANON, -1, 0); + if (p == MAP_FAILED) + return NULL; + return p; +} + +static void +free_object(void *p, size_t siz) +{ + munmap(p, siz); +} + +static void * +mmap_pages(size_t siz) +{ + void *addr; + + if (siz % PAGESIZE) + siz = (siz + PAGESIZE) & ~(PAGESIZE - 1); + + addr = mmap(0, siz, PROT_READ | PROT_WRITE, + MAP_PRIVATE | MAP_ANON, -1, 0); + if (addr == MAP_FAILED) + return NULL; + return addr; +} + +void * +malloc(size_t siz) +{ + struct node n, *an, *res; + void *p; + + if (!siz) + return NULL; + /* Lookup in the free tree for a block greater + * than or equal to `siz' bytes */ + n.siz = siz; + res = RB_NFIND(free_tree, &ft, &n); + if (!res) { + /* No available free block, create a new block + * and add it to the alloc tree */ + an = alloc_object(sizeof(*an)); + if (!an) + return NULL; + p = mmap_pages(siz); + if (!p) { + free_object(an, sizeof(*an)); + return NULL; + } + an->buf = p; + an->siz = siz; + RB_INSERT(alloc_tree, &at, an); + return an->buf; + } + an = RB_REMOVE(free_tree, &ft, res); + RB_INSERT(alloc_tree, &at, an); + return an->buf; +} + +void * +realloc(void *oldp, size_t siz) +{ + struct node n, *res; + void *p; + + if (!oldp) + return malloc(siz); + + if (!siz && oldp) { + free(oldp); + return NULL; + } + + n.buf = oldp; + /* Search the alloc tree for an allocation starting + * at address `oldp' */ + res = RB_FIND(alloc_tree, &at, &n); + if (res) { + p = malloc(siz); + if (!p) + return NULL; + memcpy(p, res->buf, siz < res->siz ? siz : res->siz); + free(res->buf); + return p; + } + return NULL; +} + +void * +calloc(size_t nmemb, size_t siz) +{ + void *p; + + p = malloc(nmemb * siz); + if (!p) + return NULL; + memset(p, 0, nmemb * siz); + return p; +} + +void +free(void *p) +{ + struct node n, *fn, *res; + + if (!p) + return; + n.buf = p; + res = RB_FIND(alloc_tree, &at, &n); + /* Lookup this allocation in the alloc tree. + * If it is located, remove it from the alloc tree + * and insert it in the free tree. */ + if (res) { + fn = RB_REMOVE(alloc_tree, &at, res); + RB_INSERT(free_tree, &ft, fn); + } +} + +void +cfree(void *p) +{ + free(p); +} + +int +posix_memalign(void **memptr, size_t align, size_t size) +{ + void *mem; + + if (((align - 1) & align)) + return EINVAL; + if (align < sizeof(void *)) + return EINVAL; + + if (PAGESIZE % align) { + fprintf(stderr, "%s: %zu alignment not supported!\n", + __func__, align); + abort(); + } + + mem = malloc(size); + if (!mem) + return ENOMEM; + + *memptr = mem; + return 0; +} + +size_t +malloc_usable_size(void *p) +{ + struct node n, *res; + + if (!p) + return 0; + n.buf = p; + res = RB_FIND(alloc_tree, &at, &n); + if (res) + return res->siz; + return 0; +} + +size_t +malloc_size(void *p) +{ + return malloc_usable_size(p); +}