Ditch dlmalloc in favour of custom umalloc

ulib/umalloc/umalloc.c

@@ -0,0 +1,89 @@
+#include <stdint.h>
+#include <stddef.h>
+#include <umalloc/umalloc.h>
+#include <sysdefs/mman.h>
+#include <system/system.h>
+#include <errors.h>
+#include <linklist.h>
+#include <string/string.h>
+#include <write/write.h>
+
+#define ARENA_SIZE (1<<20)
+
+typedef struct UmArena {
+  struct UmArena *next;
+  uintptr_t mem;
+  size_t cursor;
+  int64_t balance;
+} UmArena;
+
+static UmArena *ARENAS = NULL;
+
+UmArena *um_newarena(void) {
+  size_t arenasize = ARENA_SIZE;
+
+  uint8_t *mem = NULL;
+  int32_t err = mman_map(NULL, arenasize, MMAN_MAP_PF_RW, 0, &mem);
+  if (mem == NULL || err != E_OK) {
+    return NULL;
+  }
+  string_memset(mem, 0, arenasize);
+
+  UmArena *arena = (UmArena *)mem;
+  arena->mem = (uintptr_t)mem + sizeof(arena);
+  arena->cursor = 0;
+  LL_APPEND(ARENAS, arena);
+
+  return arena;
+}
+
+void *umalloc(size_t size) {
+  UmArena *usable = NULL;
+
+  UmArena *arena, *arenatmp;
+  LL_FOREACH_SAFE(ARENAS, arena, arenatmp) {
+    if (arena->cursor + size < ARENA_SIZE) {
+      usable = arena;
+      break;
+    }
+  }
+
+  if (usable == NULL) {
+    usable = um_newarena();
+  }
+
+  if (usable == NULL) {
+    return NULL;
+  }
+
+  uintptr_t current = usable->mem + usable->cursor;
+  usable->cursor += size;
+  usable->balance += 1;
+  return (void *)current;
+}
+
+void ufree(void *ptr_) {
+  uintptr_t ptr = (uintptr_t)ptr_;
+
+  UmArena *freeable = NULL;
+
+  UmArena *arena, *arenatmp;
+  LL_FOREACH_SAFE(ARENAS, arena, arenatmp) {
+    if (ptr >= arena->mem && ptr < arena->mem + ARENA_SIZE) {
+      freeable = arena;
+      break;
+    }
+  }
+
+  if (freeable == NULL) {
+    return;
+  }
+
+  freeable->balance -= 1;
+
+  if (freeable->balance <= 0) {
+    uintptr_t origin = (uintptr_t)freeable - sizeof(UmArena);
+    mman_unmap((void *)origin);
+  }
+}
+

ulib/umalloc/umalloc.h

@@ -0,0 +1,10 @@
+#ifndef ULIB_UMALLOC_UMALLOC_H_
+#define ULIB_UMALLOC_UMALLOC_H_
+
+#include <stdint.h>
+#include <stddef.h>
+
+void *umalloc(size_t size);
+void ufree(void *ptr_);
+
+#endif // ULIB_UMALLOC_UMALLOC_H_