1 files changed, 135 insertions, 0 deletions
diff --git a/test/arena.c b/test/arena.c
new file mode 100644
index 0000000..58b3076
--- /dev/null
+++ b/test/arena.c
@@ -0,0 +1,135 @@
+#include <sys/mman.h>
+
+#include <errno.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+#include "alloc.h"
+#include "test-internal.h"
+
+#define lengthof(xs) (sizeof(xs) / sizeof(*(xs)))
+
+static void make_and_free(void),
+            make_and_resize(void),
+            free_empty_arena(void),
+            make_snapshot(void);
+
+int
+main(void)
+{
+	make_and_free();
+	make_and_resize();
+	free_empty_arena();
+	make_snapshot();
+	return rv;
+}
+
+void
+make_and_free(void)
+{
+	arena_t a = NULL;
+	int *xs = arena_new(&a, int, 69);
+
+	for (size_t i = 0; i < 69; i++)
+		xs[i] = i;
+
+	arena_free(&a);
+}
+
+void
+make_and_resize(void)
+{
+	arena_t a = NULL;
+	size_t *xs = arena_new(&a, size_t, 100);
+	for (size_t i = 0; i < 100; i++)
+		xs[i] = i;
+
+	static size_t ranges[][2] = {
+		{  100,   1000},
+		{ 1000,  10000},
+		{10000, 100000},
+	};
+
+	for (size_t i = 0; i < lengthof(ranges); i++) {
+		size_t lo = ranges[i][0];
+		size_t hi = ranges[i][1];
+
+		xs = arena_grow(&a, xs, size_t, lo, hi);
+		for (size_t j = lo; j < hi; j++)
+			xs[j] = j;
+	}
+
+	for (size_t i = 0; i < ranges[lengthof(ranges) - 1][1]; i++)
+		oryx_assert(xs[i] == i);
+
+cleanup:
+	arena_free(&a);
+}
+
+void
+free_empty_arena(void)
+{
+	arena_free(&(arena_t){0});
+}
+
+void
+make_snapshot(void)
+{
+	arena_t a = NULL;
+
+	char      *p1, *p2, *p3;
+	snapshot_t s1,  s2,  s3;
+
+	/* The arena by default is backed my mmap(), and makes pages of size
+	   _ARENA_DFLT_CAP or larger.  This means we can test to see if the
+	   arena snapshotting is properly implemented by:
+
+	   1.  Creating allocations of the blocksize.  This ensures each
+	       allocation is on its own page as allocated by mmap(2).
+	   2.  Creating a snapshot before each allocation.
+	   3.  Restoring snapshots and checking to see which pages are still
+	       valid via mincore() which errors with ENOMEM if the page isn’t
+		   mapped.
+
+	   Technically mincore() is non-standard… but it exists on all major
+	   BSDs as well as Linux and Darwin. */
+
+	s1 = arena_snapshot_create(a); p1 = arena_new(&a, char, _ARENA_DFLT_CAP);
+	s2 = arena_snapshot_create(a); p2 = arena_new(&a, char, _ARENA_DFLT_CAP);
+	s3 = arena_snapshot_create(a); p3 = arena_new(&a, char, _ARENA_DFLT_CAP);
+
+	unsigned char *vec = NULL;
+	size_t pagesz = (size_t)sysconf(_SC_PAGESIZE);
+	oryx_assert(pagesz != (size_t)-1);
+
+	/* Vector size documented in mincore(2) */
+	vec = malloc((_ARENA_DFLT_CAP + pagesz - 1) / pagesz);
+	oryx_assert(vec != NULL);
+
+	errno = 0; mincore(p1, _ARENA_DFLT_CAP, vec); oryx_assert(errno == 0);
+	errno = 0; mincore(p2, _ARENA_DFLT_CAP, vec); oryx_assert(errno == 0);
+	errno = 0; mincore(p3, _ARENA_DFLT_CAP, vec); oryx_assert(errno == 0);
+
+	arena_snapshot_restore(&a, s3);
+	errno = 0; mincore(p1, _ARENA_DFLT_CAP, vec); oryx_assert(errno == 0);
+	errno = 0; mincore(p2, _ARENA_DFLT_CAP, vec); oryx_assert(errno == 0);
+	errno = 0; mincore(p3, _ARENA_DFLT_CAP, vec); oryx_assert(errno == ENOMEM);
+	oryx_assert(a != NULL);
+
+	arena_snapshot_restore(&a, s2);
+	errno = 0; mincore(p1, _ARENA_DFLT_CAP, vec); oryx_assert(errno == 0);
+	errno = 0; mincore(p2, _ARENA_DFLT_CAP, vec); oryx_assert(errno == ENOMEM);
+	errno = 0; mincore(p3, _ARENA_DFLT_CAP, vec); oryx_assert(errno == ENOMEM);
+	oryx_assert(a != NULL);
+
+	arena_snapshot_restore(&a, s1);
+	errno = 0; mincore(p1, _ARENA_DFLT_CAP, vec); oryx_assert(errno == ENOMEM);
+	errno = 0; mincore(p2, _ARENA_DFLT_CAP, vec); oryx_assert(errno == ENOMEM);
+	errno = 0; mincore(p3, _ARENA_DFLT_CAP, vec); oryx_assert(errno == ENOMEM);
+	oryx_assert(a == NULL);
+
+cleanup:
+	free(vec);
+	arena_free(&a);
+}