4 files changed, 97 insertions, 1 deletions

diff --git a/src/init/malloc.c b/src/init/malloc.c
new file mode 100644
index 0000000..35b1741
--- /dev/null
+++ b/src/init/malloc.c
@@ -0,0 +1,69 @@
+#include <init/malloc.h>
+#include <shared/flags.h>
+#include <shared/syscalls.h>
+#include <stdbool.h>
+
+#include <init/stdlib.h>
+
+#define MBLOCK_MAGIC 0x1337BABE
+
+struct mblock {
+	uint32_t magic;
+	size_t length; // including this struct
+	bool used;
+	struct mblock *next;
+};
+
+static struct mblock *first = NULL, *last = NULL;
+static struct mblock *expand(size_t size);
+
+void *malloc(size_t size) {
+	struct mblock *iter = first;
+	size += sizeof(struct mblock);
+	while (iter) {
+		if (!iter->used && iter->length >= size)
+			break;
+		iter = iter->next;
+	}
+
+	if (!iter) iter = expand(size);
+	if (!iter) return NULL;
+
+	iter->used = true;
+	// TODO truncate and split
+
+	return &iter[1];
+}
+
+void free(void *ptr) {
+	struct mblock *block = ptr - sizeof(struct mblock);
+	if (block->magic != MBLOCK_MAGIC) {
+		// TODO debug log switch
+		printf("didn't find MBLOCK_MAGIC @ 0x%x\n", block);
+		return;
+	}
+
+	block->used = false;
+}
+
+static struct mblock *expand(size_t size) {
+	size = (size + 4095) & ~4095; // round up to nearest page
+
+	static void *start = (void*)0x80000000; // TODO workaround for unimplemented feature
+	_syscall_memflag(start, size, MEMFLAG_PRESENT);
+	struct mblock *block = start;
+	start += size;
+
+	block->magic = MBLOCK_MAGIC;
+	block->length = size;
+	block->used = false;
+	block->next = NULL;
+
+	if (!first) first = block;
+	if (last) last->next = block;
+	last = block;
+
+	// TODO collapse
+
+	return block;
+}
diff --git a/src/init/malloc.h b/src/init/malloc.h
new file mode 100644
index 0000000..5916ebc
--- /dev/null
+++ b/src/init/malloc.h
@@ -0,0 +1,5 @@
+#pragma once
+#include <stddef.h>
+
+void *malloc(size_t size);
+void free(void *ptr);
diff --git a/src/init/stdlib.h b/src/init/stdlib.h
index f8ab6c0..b1709e0 100644
--- a/src/init/stdlib.h
+++ b/src/init/stdlib.h
@@ -1,4 +1,5 @@
 #pragma once
+#include <init/malloc.h>
 #include <shared/mem.h>
 #include <stdbool.h>
 #include <stddef.h>
diff --git a/src/init/tests/main.c b/src/init/tests/main.c
index 20923b0..29f6c61 100644
--- a/src/init/tests/main.c
+++ b/src/init/tests/main.c
@@ -109,6 +109,26 @@ static void test_memflag(void) {
 	// TODO the kernel shouldn't even be mapped in userland
 }
 
+static void test_malloc(void) {
+	// not really a test
+	void *p1, *p2, *p3;
+
+	p1 = malloc(420);
+	printf("p1 = 0x%x\n", p1);
+
+	p2 = malloc(1024);
+	printf("p2 = 0x%x\n", p2);
+	free(p2);
+	p2 = malloc(256);
+	printf("p2 = 0x%x\n", p2);
+	free(p2);
+	p2 = malloc(4096);
+	printf("p2 = 0x%x\n", p2);
+	free(p2);
+
+	free(p1);
+}
+
 static void stress_fork(void) {
 	/* run a lot of processes */
 	for (size_t i = 0; i < 2048; i++) {
@@ -124,5 +144,6 @@ void test_all(void) {
 	run_forked(test_interrupted_fs);
 	run_forked(test_orphaned_fs);
 	run_forked(test_memflag);
-	run_forked(stress_fork);
+	run_forked(test_malloc);
+//	run_forked(stress_fork);
 }