2015-02-03 03:53:19

by Michael Ellerman

[permalink] [raw]
Subject: [PATCH v2] selftests/exec: Check if the syscall exists and bail if not

On systems which don't implement sys_execveat(), this test produces a
lot of output.

Add a check at the beginning to see if the syscall is present, and if
not just note one error and return.

When we run on a system that doesn't implement the syscall we will get
ENOSYS back from the kernel, so change the logic that handles
__NR_execveat not being defined to also use ENOSYS rather than -ENOSYS.

Signed-off-by: Michael Ellerman <[email protected]>
---

v2: Switch to positive ENOSYS. Confirmed this works as expected in the
case where the syscall is defined, but then is not present at runtime.


tools/testing/selftests/exec/execveat.c | 10 +++++++++-
1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/exec/execveat.c b/tools/testing/selftests/exec/execveat.c
index e238c9559caf..8d5d1d2ee7c1 100644
--- a/tools/testing/selftests/exec/execveat.c
+++ b/tools/testing/selftests/exec/execveat.c
@@ -30,7 +30,7 @@ static int execveat_(int fd, const char *path, char **argv, char **envp,
#ifdef __NR_execveat
return syscall(__NR_execveat, fd, path, argv, envp, flags);
#else
- errno = -ENOSYS;
+ errno = ENOSYS;
return -1;
#endif
}
@@ -234,6 +234,14 @@ static int run_tests(void)
int fd_cloexec = open_or_die("execveat", O_RDONLY|O_CLOEXEC);
int fd_script_cloexec = open_or_die("script", O_RDONLY|O_CLOEXEC);

+ /* Check if we have execveat at all, and bail early if not */
+ errno = 0;
+ execveat_(-1, NULL, NULL, NULL, 0);
+ if (errno == ENOSYS) {
+ printf("[FAIL] ENOSYS calling execveat - no kernel support?\n");
+ return 1;
+ }
+
/* Change file position to confirm it doesn't affect anything */
lseek(fd, 10, SEEK_SET);

--
2.1.0


2015-02-03 07:59:22

by David Drysdale

[permalink] [raw]
Subject: Re: [PATCH v2] selftests/exec: Check if the syscall exists and bail if not

On Tue, Feb 3, 2015 at 3:53 AM, Michael Ellerman <[email protected]> wrote:
> On systems which don't implement sys_execveat(), this test produces a
> lot of output.
>
> Add a check at the beginning to see if the syscall is present, and if
> not just note one error and return.
>
> When we run on a system that doesn't implement the syscall we will get
> ENOSYS back from the kernel, so change the logic that handles
> __NR_execveat not being defined to also use ENOSYS rather than -ENOSYS.
>
> Signed-off-by: Michael Ellerman <[email protected]>

Acked-by: David Drysdale <[email protected]>

> ---
>
> v2: Switch to positive ENOSYS. Confirmed this works as expected in the
> case where the syscall is defined, but then is not present at runtime.

Thanks!

>
> tools/testing/selftests/exec/execveat.c | 10 +++++++++-
> 1 file changed, 9 insertions(+), 1 deletion(-)
>
> diff --git a/tools/testing/selftests/exec/execveat.c b/tools/testing/selftests/exec/execveat.c
> index e238c9559caf..8d5d1d2ee7c1 100644
> --- a/tools/testing/selftests/exec/execveat.c
> +++ b/tools/testing/selftests/exec/execveat.c
> @@ -30,7 +30,7 @@ static int execveat_(int fd, const char *path, char **argv, char **envp,
> #ifdef __NR_execveat
> return syscall(__NR_execveat, fd, path, argv, envp, flags);
> #else
> - errno = -ENOSYS;
> + errno = ENOSYS;
> return -1;
> #endif
> }
> @@ -234,6 +234,14 @@ static int run_tests(void)
> int fd_cloexec = open_or_die("execveat", O_RDONLY|O_CLOEXEC);
> int fd_script_cloexec = open_or_die("script", O_RDONLY|O_CLOEXEC);
>
> + /* Check if we have execveat at all, and bail early if not */
> + errno = 0;
> + execveat_(-1, NULL, NULL, NULL, 0);
> + if (errno == ENOSYS) {
> + printf("[FAIL] ENOSYS calling execveat - no kernel support?\n");
> + return 1;
> + }
> +
> /* Change file position to confirm it doesn't affect anything */
> lseek(fd, 10, SEEK_SET);
>
> --
> 2.1.0
>

2015-02-03 15:32:47

by Shuah Khan

[permalink] [raw]
Subject: Re: [PATCH v2] selftests/exec: Check if the syscall exists and bail if not

On 02/03/2015 12:58 AM, David Drysdale wrote:
> On Tue, Feb 3, 2015 at 3:53 AM, Michael Ellerman <[email protected]> wrote:
>> On systems which don't implement sys_execveat(), this test produces a
>> lot of output.
>>
>> Add a check at the beginning to see if the syscall is present, and if
>> not just note one error and return.
>>
>> When we run on a system that doesn't implement the syscall we will get
>> ENOSYS back from the kernel, so change the logic that handles
>> __NR_execveat not being defined to also use ENOSYS rather than -ENOSYS.
>>
>> Signed-off-by: Michael Ellerman <[email protected]>
>
> Acked-by: David Drysdale <[email protected]>

Thanks Michael, and David. I will queue this for 3.20

-- Shuah


--
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
[email protected] | (970) 217-8978

2015-02-04 02:46:37

by Michael Ellerman

[permalink] [raw]
Subject: Re: [PATCH v2] selftests/exec: Check if the syscall exists and bail if not

On Tue, 2015-02-03 at 08:32 -0700, Shuah Khan wrote:
> On 02/03/2015 12:58 AM, David Drysdale wrote:
> > On Tue, Feb 3, 2015 at 3:53 AM, Michael Ellerman <[email protected]> wrote:
> >> On systems which don't implement sys_execveat(), this test produces a
> >> lot of output.
> >>
> >> Add a check at the beginning to see if the syscall is present, and if
> >> not just note one error and return.
> >>
> >> When we run on a system that doesn't implement the syscall we will get
> >> ENOSYS back from the kernel, so change the logic that handles
> >> __NR_execveat not being defined to also use ENOSYS rather than -ENOSYS.
> >>
> >> Signed-off-by: Michael Ellerman <[email protected]>
> >
> > Acked-by: David Drysdale <[email protected]>
>
> Thanks Michael, and David. I will queue this for 3.20

Thanks.

cheers