all: add optional close_fds feature to reproducers

Instead of always closing open fds (number 3 to 30) after each program,
add an options called EnableCloseFds. It can be passed to syz-execprog,
syz-prog2c and syz-stress via the -enable and -disable flags. Set the
default value to true. Also minimize C repros over it, except for when
repeat is enabled.

1 files changed, 10 insertions, 2 deletions

diff --git a/executor/common_linux.h b/executor/common_linux.h
index b84955577..0fd7a1582 100644
--- a/executor/common_linux.h
+++ b/executor/common_linux.h
@@ -2612,12 +2612,20 @@ static void setup_test()
 	flush_tun();
 #endif
 }
+#endif
 
-#define SYZ_HAVE_RESET_TEST 1
-static void reset_test()
+#if SYZ_EXECUTOR || SYZ_ENABLE_CLOSE_FDS
+#define SYZ_HAVE_CLOSE_FDS 1
+static void close_fds()
 {
+#if SYZ_EXECUTOR
+	if (!flag_enable_close_fds)
+		return;
+#endif
 	// Keeping a 9p transport pipe open will hang the proccess dead,
 	// so close all opened file descriptors.
+	// Also close all USB emulation descriptors to trigger exit from USB
+	// event loop to collect coverage.
 	int fd;
 	for (fd = 3; fd < 30; fd++)
 		close(fd);