Re: [LTP] [PATCH] readlink03: fix return value for the syscall readlink()

[Wanlong G. <gao...@cn...>]

Hi Cyril:

When you have time, I wanna know what do you think about this.

Thanks
-Wanlong Gao

> Since commit http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=65cfc6722361570bfe255698d9cd4dccaf47570d
> which added O_PATH support to the *at() calls, the error return for readlink/readlinkat
> for the empty pathname has switched from ENOENT to EINVAL. And this patch merged to linux v2.6.39,
> So LTP commit http://ltp.git.sourceforge.net/git/gitweb.cgi?p=ltp/ltp.git;a=commitdiff;h=0cc75148b95e2ed8ecb311f20d91f449461d8860
> fix this with the kernel version v2.6.39 compared.
> 
> But recently, commit http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=1fa1e7f615f4d3ae436fa319af6e4eebdd4026a8
> which ensure we return ENOENT for the empty pathname for normal lookups.
> 
> Now, the patch whitch switch the return value back again is already queued for
> 3.0 and 3.1 stable release.
> 
> So, if the return value is EINVAL for empty pathname, it may be a kernel bug, so we
> needn't to check the kernel version but return the "kernel bug" INFO to LTP the users.
> 
> Signed-off-by: Wanlong Gao <gao...@cn...>
> ---
>  testcases/kernel/syscalls/readlink/readlink03.c |   10 +++++-----
>  1 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/testcases/kernel/syscalls/readlink/readlink03.c b/testcases/kernel/syscalls/readlink/readlink03.c
> index 370bf7d..298d863 100644
> --- a/testcases/kernel/syscalls/readlink/readlink03.c
> +++ b/testcases/kernel/syscalls/readlink/readlink03.c
> @@ -173,11 +173,6 @@ int main(int ac, char **av)
>  				buf_size = sizeof(buffer);
>  			}
>  
> -			if (strncmp(test_desc, "Symlink Pathname is empty", 25) == 0) {
> -				if ((tst_kvercmp(2, 6, 39)) >= 0)
> -					Test_cases[i].exp_errno = EINVAL;
> -			}
> -
>  			/*
>  			 * Call readlink(2) to test different test conditions.
>  			 * verify that it fails with -1 return value and sets
> @@ -204,6 +199,11 @@ int main(int ac, char **av)
>  					 "errno=%d, expected errno=%d",
>  					 test_desc, TEST_ERRNO,
>  					 Test_cases[i].exp_errno);
> +				if ((strncmp(test_desc, "Symlink Pathname is empty", 25) == 0) &&
> +				     TEST_ERRNO == EINVAL) {
> +					printf("It may be a Kernel Bug, see the patch:\n"
> +					       "http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=1fa1e7f615f4d3ae436fa319af6e4eebdd4026a8\n");
> +				}
>  			}
>  		}
>  	}