Re: [PATCH v2 2/2] selftests: add tests for CLOSE_RANGE_CLOEXEC

[Christian Brauner]

First, thank you for the selftests. That's great to see!

Could you please add a short explanation what you're testing here to the
commit message?

On Mon, Oct 19, 2020 at 12:26:54PM +0200, Giuseppe Scrivano wrote:
> Signed-off-by: Giuseppe Scrivano <gscrivan@xxxxxxxxxx>
> ---
>  .../testing/selftests/core/close_range_test.c | 74 +++++++++++++++++++
>  1 file changed, 74 insertions(+)
> 
> diff --git a/tools/testing/selftests/core/close_range_test.c b/tools/testing/selftests/core/close_range_test.c
> index c99b98b0d461..c9db282158bb 100644
> --- a/tools/testing/selftests/core/close_range_test.c
> +++ b/tools/testing/selftests/core/close_range_test.c
> @@ -11,6 +11,7 @@
>  #include <string.h>
>  #include <syscall.h>
>  #include <unistd.h>
> +#include <sys/resource.h>
>  
>  #include "../kselftest_harness.h"
>  #include "../clone3/clone3_selftests.h"
> @@ -23,6 +24,10 @@
>  #define CLOSE_RANGE_UNSHARE	(1U << 1)
>  #endif
>  
> +#ifndef CLOSE_RANGE_CLOEXEC
> +#define CLOSE_RANGE_CLOEXEC	(1U << 2)
> +#endif
> +
>  static inline int sys_close_range(unsigned int fd, unsigned int max_fd,
>  				  unsigned int flags)
>  {
> @@ -224,4 +229,73 @@ TEST(close_range_unshare_capped)
>  	EXPECT_EQ(0, WEXITSTATUS(status));
>  }
>  
> +TEST(close_range_cloexec)
> +{
> +	int i, ret;
> +	int open_fds[101];
> +	struct rlimit rlimit;
> +
> +	for (i = 0; i < ARRAY_SIZE(open_fds); i++) {
> +		int fd;
> +
> +		fd = open("/dev/null", O_RDONLY);
> +		ASSERT_GE(fd, 0) {
> +			if (errno == ENOENT)
> +				XFAIL(return, "Skipping test since /dev/null does not exist");
> +		}
> +
> +		open_fds[i] = fd;
> +	}
> +
> +	ret = sys_close_range(1000, 1000, CLOSE_RANGE_CLOEXEC);
> +	if (ret < 0) {
> +		if (errno == ENOSYS)
> +			XFAIL(return, "close_range() syscall not supported");
> +		if (errno == EINVAL)
> +			XFAIL(return, "close_range() doesn't support CLOSE_RANGE_CLOEXEC");
> +	}
> +
> +	/* Ensure the FD_CLOEXEC bit is set also with a resource limit in place.  */
> +	EXPECT_EQ(0, getrlimit(RLIMIT_NOFILE, &rlimit));
> +	rlimit.rlim_cur = 25;
> +	EXPECT_EQ(0, setrlimit(RLIMIT_NOFILE, &rlimit));

I usually prefer to call ASSERT_* to abort at the first true failure
before moving on. And I think all the EXPECT_*()s here should be
ASSERT_*()s because that are all hard failures imho.

Apart from that this looks good.

> +
> +	/* Set close-on-exec for two ranges: [0-50] and [75-100].  */
> +	ret = sys_close_range(open_fds[0], open_fds[50], CLOSE_RANGE_CLOEXEC);
> +	EXPECT_EQ(0, ret);
> +	ret = sys_close_range(open_fds[75], open_fds[100], CLOSE_RANGE_CLOEXEC);
> +	EXPECT_EQ(0, ret);
> +
> +	for (i = 0; i <= 50; i++) {
> +		int flags = fcntl(open_fds[i], F_GETFD);
> +
> +		EXPECT_GT(flags, -1);
> +		EXPECT_EQ(flags & FD_CLOEXEC, FD_CLOEXEC);
> +	}
> +
> +	for (i = 51; i <= 74; i++) {
> +		int flags = fcntl(open_fds[i], F_GETFD);
> +
> +		EXPECT_GT(flags, -1);
> +		EXPECT_EQ(flags & FD_CLOEXEC, 0);
> +	}
> +
> +	for (i = 75; i <= 100; i++) {
> +		int flags = fcntl(open_fds[i], F_GETFD);
> +
> +		EXPECT_GT(flags, -1);
> +		EXPECT_EQ(flags & FD_CLOEXEC, FD_CLOEXEC);
> +	}
> +
> +	/* Test a common pattern.  */
> +	ret = sys_close_range(3, UINT_MAX, CLOSE_RANGE_CLOEXEC);
> +	for (i = 0; i <= 100; i++) {
> +		int flags = fcntl(open_fds[i], F_GETFD);
> +
> +		EXPECT_GT(flags, -1);
> +		EXPECT_EQ(flags & FD_CLOEXEC, FD_CLOEXEC);
> +	}
> +}
> +
> +
>  TEST_HARNESS_MAIN
> -- 
> 2.26.2
> 
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