sys/test: add more tests

Add syz_errno syscall which sets errno to the argument,
and add a test with different errno values.
This mostly tests the testing infrastructure itself.

Add syz_compare syscall which compare two blobs,
this can be used for testing of argument memory layout.

Implement syz_mmap and fix Makefile to allow building syz-execprog for test OS.
Useful for debugging.

Update #603

1 files changed, 35 insertions, 0 deletions

diff --git a/executor/common_test.h b/executor/common_test.h
index 78b3f8e22..75ec81721 100644
--- a/executor/common_test.h
+++ b/executor/common_test.h
@@ -7,8 +7,43 @@
 #include <unistd.h>
 
 #if SYZ_EXECUTOR || __NR_syz_mmap
+#include <sys/mman.h>
+
+// syz_mmap(addr vma, len len[addr])
 static long syz_mmap(long a0, long a1)
 {
+	return (long)mmap((void*)a0, a1, PROT_READ | PROT_WRITE, MAP_ANON | MAP_PRIVATE | MAP_FIXED, -1, 0);
+}
+#endif
+
+#if SYZ_EXECUTOR || __NR_syz_errno
+#include <errno.h>
+
+// syz_errno(v int32)
+static long syz_errno(long v)
+{
+	errno = v;
+	return v == 0 ? 0 : -1;
+}
+#endif
+
+#if SYZ_EXECUTOR || __NR_syz_compare
+#include <errno.h>
+#include <string.h>
+
+// syz_compare(want ptr[in, string], want_len len[want], got ptr[in, compare_data], got_len len[got])
+static long syz_compare(long want, long want_len, long got, long got_len)
+{
+	if (want_len != got_len) {
+		debug("syz_compare: want_len=%lu got_len=%lu\n", want_len, got_len);
+		errno = EBADF;
+		return -1;
+	}
+	if (memcmp((void*)want, (void*)got, want_len)) {
+		debug("syz_compare: data differs\n");
+		errno = EINVAL;
+		return -1;
+	}
 	return 0;
 }
 #endif