From 17fd9daf39cf79ae310c1b7d0eb459802517dc6a Mon Sep 17 00:00:00 2001
From: Kimplul <kimi.h.kuparinen@gmail.com>
Date: Sat, 2 Nov 2024 16:34:38 +0200
Subject: check spawn exhaustion

---
 src/regions.c                    |  6 ++++++
 src/uapi/proc.c                  | 10 +++++++---
 tests/spawn-exhaustion/init.c    | 35 +++++++++++++++++++++++++++++++++++
 tests/spawn-exhaustion/source.mk |  1 +
 tests/spawn-exhaustion/spawn.c   | 14 ++++++++++++++
 5 files changed, 63 insertions(+), 3 deletions(-)
 create mode 100644 tests/spawn-exhaustion/init.c
 create mode 100644 tests/spawn-exhaustion/source.mk
 create mode 100644 tests/spawn-exhaustion/spawn.c

diff --git a/src/regions.c b/src/regions.c
index 2c11db0..163ec82 100644
--- a/src/regions.c
+++ b/src/regions.c
@@ -35,6 +35,9 @@ void destroy_mem_nodes()
 static struct mem_region *get_mem_node()
 {
 	struct mem_region *r = get_node(&root);
+	if (!r)
+		return NULL;
+
 	memset(r, 0, sizeof(struct mem_region));
 	return r;
 }
@@ -178,6 +181,9 @@ stat_t init_region(struct mem_region_root *r, vm_t start, size_t arena_size,
 	start = __page(start);
 	arena_size = __page(arena_size);
 	struct mem_region *m = get_mem_node();
+	if (!m)
+		return ERR_OOMEM;
+
 	m->start = start;
 	m->end = start + arena_size;
 	m->flags = 0;
diff --git a/src/uapi/proc.c b/src/uapi/proc.c
index 51a1252..5eb3013 100644
--- a/src/uapi/proc.c
+++ b/src/uapi/proc.c
@@ -154,11 +154,15 @@ SYSCALL_DEFINE2(spawn)(struct tcb *t, sys_arg_t bin, sys_arg_t interp)
 	if (!n)
 		return_args1(t, ERR_OOMEM);
 
+	/** @todo there's currently a kind of silly thing where create_proc()
+	 * creates a new thread and calls init_uvmem() on it, and now the elf
+	 * loader called from prepare_proc() moves that uvmem aside, calls
+	 * init_uvmem() again and finally destroys the old uvmem (assuming
+	 * everything went as it was supposed to). Might have to rething these
+	 * internal APIs a bit, but for now this ~works~. */
 	n->notify_id = c->notify_id;
 	if (prepare_proc(n, bin, interp)) {
-		/* this kills the thread */
-		orphanize(t);
-		unorphanize(t);
+		destroy_proc(n);
 		return_args1(t, ERR_INVAL);
 	}
 
diff --git a/tests/spawn-exhaustion/init.c b/tests/spawn-exhaustion/init.c
new file mode 100644
index 0000000..1862648
--- /dev/null
+++ b/tests/spawn-exhaustion/init.c
@@ -0,0 +1,35 @@
+#include <common/test.h>
+#include <common/cpio.h>
+
+START(pid, tid, d0, d1, d2, d3)
+{
+	UNUSED(pid);
+	UNUSED(tid);
+	UNUSED(d0);
+	UNUSED(d1);
+	UNUSED(d2);
+	UNUSED(d3);
+
+	check(pid == 0, "illegal pid for init\n");
+	printf("finding spawn in cpio archive %lx...\n", d2);
+	struct cpio_header *cp = cpio_find_file((const void *)d2,
+			"spawn", sizeof("spawn") - 1);
+
+	check(cp, "couldn't find spawn?\n");
+	long name_len = convnum(cp->c_namesize, 8, 16);
+	uintptr_t spawn = (uintptr_t)(cp) + align_up(sizeof(struct cpio_header) + name_len, 4);
+	printf("found spawn at %lx\n", spawn);
+
+	printf("doing spawns...\n");
+
+	int counter = 0;
+	while (1) {
+		printf("spawning %d\n", counter++);
+		id_t new = sys_spawn(spawn, 0);
+		if (new < 0)
+			break;
+	}
+
+	/* could also check for memory leaks but this is good enough for now */
+	ok();
+}
diff --git a/tests/spawn-exhaustion/source.mk b/tests/spawn-exhaustion/source.mk
new file mode 100644
index 0000000..c665e49
--- /dev/null
+++ b/tests/spawn-exhaustion/source.mk
@@ -0,0 +1 @@
+DO	!= ./scripts/gen-simple -n spawn-exhaustion -p init -p spawn
diff --git a/tests/spawn-exhaustion/spawn.c b/tests/spawn-exhaustion/spawn.c
new file mode 100644
index 0000000..e281fc8
--- /dev/null
+++ b/tests/spawn-exhaustion/spawn.c
@@ -0,0 +1,14 @@
+#include <common/test.h>
+
+START(pid, tid, d0, d1, d2, d3)
+{
+	UNUSED(pid);
+	UNUSED(tid);
+	UNUSED(d0);
+	UNUSED(d1);
+	UNUSED(d2);
+	UNUSED(d3);
+
+	printf("shouldn't be here\n");
+	/* just die or something */
+}
-- 
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