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umalloc small bug fixes

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This commit is contained in:
Kamil Kowalczyk
2025-09-27 22:58:22 +02:00
parent 8d081bedb0
commit c07a2c957b
1 changed files with 14 additions and 7 deletions
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21
ulib/umalloc/umalloc.c
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@ -7,6 +7,7 @@
#include <linklist.h>
#include <string/string.h>
#include <write/write.h>
#include <util/util.h>
#define ARENA_SIZE (1<<20)
@ -14,7 +15,7 @@ typedef struct UmArena {
struct UmArena *next;
uintptr_t mem;
size_t cursor;
int64_t balance;
int balance;
} UmArena;
static UmArena *ARENAS = NULL;
@ -30,7 +31,7 @@ UmArena *um_newarena(void) {
string_memset(mem, 0, arenasize);
UmArena *arena = (UmArena *)mem;
arena->mem = (uintptr_t)mem + sizeof(arena);
arena->mem = (uintptr_t)mem + sizeof(UmArena);
arena->cursor = 0;
LL_APPEND(ARENAS, arena);
@ -42,7 +43,7 @@ void *umalloc(size_t size) {
UmArena *arena, *arenatmp;
LL_FOREACH_SAFE(ARENAS, arena, arenatmp) {
if (arena->cursor + size < ARENA_SIZE) {
if (arena->cursor + size <= ARENA_SIZE - sizeof(UmArena)) {
usable = arena;
break;
}
@ -69,7 +70,7 @@ void ufree(void *ptr_) {
UmArena *arena, *arenatmp;
LL_FOREACH_SAFE(ARENAS, arena, arenatmp) {
if (ptr >= arena->mem && ptr < arena->mem + ARENA_SIZE) {
if (ptr >= arena->mem && ptr < arena->mem + ARENA_SIZE - sizeof(UmArena)) {
freeable = arena;
break;
}
@ -81,9 +82,15 @@ void ufree(void *ptr_) {
freeable->balance -= 1;
if (freeable->balance <= 0) {
uintptr_t origin = (uintptr_t)freeable - sizeof(UmArena);
mman_unmap((void *)origin);
if (freeable->balance < 0) {
writefmt("umalloc: ufree() called more times than umalloc() ({d})\n", freeable->balance);
quit();
}
if (freeable->balance == 0) {
LL_REMOVE(ARENAS, freeable);
mman_unmap((void *)(freeable->mem - sizeof(UmArena)));
}
}