[LTP] [PATCH] Introduce ioctl_pidfd_get_info_supported() function

[LTP] [PATCH] Introduce ioctl_pidfd_get_info_supported() function

[Avinesh Kumar]

- use new routine in ioctl_pidfd05 test
- refactor ioctl_pidfd_info_exit_supported() routine

Suggested-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Avinesh Kumar <akumar@suse.de>
---
 testcases/kernel/syscalls/ioctl/ioctl_pidfd.h | 45 +++++++++++--------
 .../kernel/syscalls/ioctl/ioctl_pidfd05.c     |  9 +++-
 2 files changed, 34 insertions(+), 20 deletions(-)

diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h b/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
index 811f969cd..6ee6c6db5 100644
--- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
+++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
@@ -9,19 +9,16 @@
 #include "tst_test.h"
 #include "lapi/pidfd.h"
 
-static inline int ioctl_pidfd_info_exit_supported(void)
+static inline long ioctl_pidfd_get_info_supported(void)
 {
-	int ret;
 	pid_t pid;
-	int pidfd;
-	int supported = 0;
+	int pidfd, ret;
 	struct pidfd_info info;
 
-	if (tst_kvercmp(6, 15, 0) >= 0)
+	if (tst_kvercmp(6, 12, 0) >= 0)
 		return 1;
 
 	memset(&info, 0, sizeof(struct pidfd_info));
-	info.mask = PIDFD_INFO_EXIT;
 
 	pid = SAFE_FORK();
 	if (!pid)
@@ -31,23 +28,33 @@ static inline int ioctl_pidfd_info_exit_supported(void)
 	SAFE_WAITPID(pid, NULL, 0);
 
 	ret = ioctl(pidfd, PIDFD_GET_INFO, &info);
+	SAFE_CLOSE(pidfd);
+
 	if (ret == -1) {
-		/* - ENOTTY: old kernels not implementing fs/pidfs.c:pidfd_ioctl
-		 * - EINVAL: until v6.13 kernel
-		 * - ESRCH: all kernels between v6.13 and v6.15
-		 */
-		if (errno != ENOTTY &&
-			errno != EINVAL &&
-			errno != ESRCH)
-			tst_brk(TBROK | TERRNO, "ioctl error");
-	} else {
-		if (info.mask & PIDFD_INFO_EXIT)
-			supported = 1;
+		if (errno == ENOTTY)
+			return -1;
+
+		if (errno == EINVAL || errno == ESRCH)
+			return 0;
+
+		tst_brk(TBROK | TERRNO, "unexpected ioctl(PIDFD_GET_INFO) error");
 	}
 
-	SAFE_CLOSE(pidfd);
+	return info.mask;
+}
+
+static inline int ioctl_pidfd_info_exit_supported(void)
+{
+	long mask;
+
+	if (tst_kvercmp(6, 15, 0) >= 0)
+		return 1;
+
+	mask = ioctl_pidfd_get_info_supported();
+	if (mask == -1)
+		return 0;
 
-	return supported;
+	return !!(mask & PIDFD_INFO_EXIT);
 }
 
 #endif
diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
index c379717b3..871f2fe5e 100644
--- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
+++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
@@ -14,7 +14,7 @@
 #include "tst_test.h"
 #include "lapi/pidfd.h"
 #include "lapi/sched.h"
-#include "lapi/ioctl.h"
+#include "ioctl_pidfd.h"
 
 struct pidfd_info_invalid {
 	uint32_t dummy;
@@ -48,8 +48,15 @@ static void run(void)
 	SAFE_CLOSE(pidfd);
 }
 
+static void setup(void)
+{
+	if (ioctl_pidfd_get_info_supported() == -1)
+		tst_brk(TCONF, "ioctl(PIDFD_GET_INFO) is not implemented");
+}
+
 static struct tst_test test = {
 	.test_all = run,
+	.setup = setup,
 	.forks_child = 1,
 	.bufs = (struct tst_buffers []) {
 		{&args, .size = sizeof(*args)},
-- 
2.51.0


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Re: [LTP] [PATCH] Introduce ioctl_pidfd_get_info_supported() function

[Petr Vorel]

Hi Avinesh,

thanks for fixing this!
...
>  	if (ret == -1) {
> +		if (errno == ENOTTY)
> +			return -1;
> +
> +		if (errno == EINVAL || errno == ESRCH)
> +			return 0;
> +
> +		tst_brk(TBROK | TERRNO, "unexpected ioctl(PIDFD_GET_INFO) error");
>  	}

> -	SAFE_CLOSE(pidfd);
> +	return info.mask;

Because ioctl_pidfd_get_info_supported() returns 3 different states
(-1 (not supported), 0 (supported) and >= 0 (mask) it wouldn't harm to document
return type.

All the more so because ioctl_pidfd_info_exit_supported() uses reversed
conditions for supported (1) / not supported (0).

I understand chosen values, but because names suggest the same functionality doc
would help.

> +}
> +
> +static inline int ioctl_pidfd_info_exit_supported(void)
This could be bool, that's itself a documentation (just 2 possible values, not
more).

Kind regards,
Petr

> +{
> +	long mask;
> +
> +	if (tst_kvercmp(6, 15, 0) >= 0)
> +		return 1;
> +
> +	mask = ioctl_pidfd_get_info_supported();
> +	if (mask == -1)
> +		return 0;

> -	return supported;
> +	return !!(mask & PIDFD_INFO_EXIT);
>  }

-- 
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[LTP] [PATCH v2] Introduce ioctl_pidfd_get_info_supported() function

[Avinesh Kumar]

- use new routine in ioctl_pidfd05 test
- refactor ioctl_pidfd_info_exit_supported() routine

Suggested-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Avinesh Kumar <akumar@suse.de>
---
 testcases/kernel/syscalls/ioctl/ioctl_pidfd.h | 49 ++++++++++++-------
 .../kernel/syscalls/ioctl/ioctl_pidfd05.c     |  9 +++-
 2 files changed, 39 insertions(+), 19 deletions(-)

diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h b/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
index 811f969cd..067ef18ba 100644
--- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
+++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
@@ -9,19 +9,16 @@
 #include "tst_test.h"
 #include "lapi/pidfd.h"
 
-static inline int ioctl_pidfd_info_exit_supported(void)
+static inline long ioctl_pidfd_get_info_supported(void)
 {
-	int ret;
 	pid_t pid;
-	int pidfd;
-	int supported = 0;
+	int pidfd, ret;
 	struct pidfd_info info;
 
-	if (tst_kvercmp(6, 15, 0) >= 0)
+	if (tst_kvercmp(6, 12, 0) >= 0)
 		return 1;
 
 	memset(&info, 0, sizeof(struct pidfd_info));
-	info.mask = PIDFD_INFO_EXIT;
 
 	pid = SAFE_FORK();
 	if (!pid)
@@ -31,23 +28,39 @@ static inline int ioctl_pidfd_info_exit_supported(void)
 	SAFE_WAITPID(pid, NULL, 0);
 
 	ret = ioctl(pidfd, PIDFD_GET_INFO, &info);
+	SAFE_CLOSE(pidfd);
+
 	if (ret == -1) {
-		/* - ENOTTY: old kernels not implementing fs/pidfs.c:pidfd_ioctl
-		 * - EINVAL: until v6.13 kernel
-		 * - ESRCH: all kernels between v6.13 and v6.15
+		/* - ENOTTY: kernel too old, ioctl(PIDFD_GET_INFO) not implemented; return -1 */
+		if (errno == ENOTTY)
+			return -1;
+
+		/* - EINVAL: ioctl(PIDFD_GET_INFO) exists but invalid args
+		 * - ESRCH: ioctl(PIDFD_GET_INFO) exists but task already exited
+		 * both mean supported, but info.mask is not set; return 0
 		 */
-		if (errno != ENOTTY &&
-			errno != EINVAL &&
-			errno != ESRCH)
-			tst_brk(TBROK | TERRNO, "ioctl error");
-	} else {
-		if (info.mask & PIDFD_INFO_EXIT)
-			supported = 1;
+		if (errno == EINVAL || errno == ESRCH)
+			return 0;
+
+		tst_brk(TBROK | TERRNO, "unexpected ioctl(PIDFD_GET_INFO) error");
 	}
 
-	SAFE_CLOSE(pidfd);
+	/* ioctl(PIDFD_GET_INFO) successful; return mask */
+	return info.mask;
+}
+
+static inline bool ioctl_pidfd_info_exit_supported(void)
+{
+	long mask;
+
+	if (tst_kvercmp(6, 15, 0) >= 0)
+		return 1;
+
+	mask = ioctl_pidfd_get_info_supported();
+	if (mask == -1)
+		return 0;
 
-	return supported;
+	return !!(mask & PIDFD_INFO_EXIT);
 }
 
 #endif
diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
index c379717b3..871f2fe5e 100644
--- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
+++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
@@ -14,7 +14,7 @@
 #include "tst_test.h"
 #include "lapi/pidfd.h"
 #include "lapi/sched.h"
-#include "lapi/ioctl.h"
+#include "ioctl_pidfd.h"
 
 struct pidfd_info_invalid {
 	uint32_t dummy;
@@ -48,8 +48,15 @@ static void run(void)
 	SAFE_CLOSE(pidfd);
 }
 
+static void setup(void)
+{
+	if (ioctl_pidfd_get_info_supported() == -1)
+		tst_brk(TCONF, "ioctl(PIDFD_GET_INFO) is not implemented");
+}
+
 static struct tst_test test = {
 	.test_all = run,
+	.setup = setup,
 	.forks_child = 1,
 	.bufs = (struct tst_buffers []) {
 		{&args, .size = sizeof(*args)},
-- 
2.51.0


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Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH v2] Introduce ioctl_pidfd_get_info_supported() function

[Petr Vorel]

Hi Avinesh,

...
>  	if (ret == -1) {
> -		/* - ENOTTY: old kernels not implementing fs/pidfs.c:pidfd_ioctl
> -		 * - EINVAL: until v6.13 kernel
> -		 * - ESRCH: all kernels between v6.13 and v6.15
> +		/* - ENOTTY: kernel too old, ioctl(PIDFD_GET_INFO) not implemented; return -1 */
> +		if (errno == ENOTTY)
> +			return -1;
> +
> +		/* - EINVAL: ioctl(PIDFD_GET_INFO) exists but invalid args
> +		 * - ESRCH: ioctl(PIDFD_GET_INFO) exists but task already exited
> +		 * both mean supported, but info.mask is not set; return 0
>  		 */
I originally mean to move the docs above function signature (to the top)
and add it for both, but I suppose this is perfectly ok (it was here before).

Thanks for improving it.

Reviewed-by: Petr Vorel <pvorel@suse.cz>

Kind regards,
Petr

> -		if (errno != ENOTTY &&
> -			errno != EINVAL &&
> -			errno != ESRCH)
> -			tst_brk(TBROK | TERRNO, "ioctl error");
> -	} else {
> -		if (info.mask & PIDFD_INFO_EXIT)
> -			supported = 1;
> +		if (errno == EINVAL || errno == ESRCH)
> +			return 0;
> +
> +		tst_brk(TBROK | TERRNO, "unexpected ioctl(PIDFD_GET_INFO) error");
>  	}

> -	SAFE_CLOSE(pidfd);
> +	/* ioctl(PIDFD_GET_INFO) successful; return mask */
> +	return info.mask;
> +}
> +
> +static inline bool ioctl_pidfd_info_exit_supported(void)
> +{
...

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Re: [LTP] [PATCH v2] Introduce ioctl_pidfd_get_info_supported() function

[Cyril Hrubis]

Hi!
> - use new routine in ioctl_pidfd05 test
> - refactor ioctl_pidfd_info_exit_supported() routine
> 
> Suggested-by: Petr Vorel <pvorel@suse.cz>
> Signed-off-by: Avinesh Kumar <akumar@suse.de>
> ---
>  testcases/kernel/syscalls/ioctl/ioctl_pidfd.h | 49 ++++++++++++-------
>  .../kernel/syscalls/ioctl/ioctl_pidfd05.c     |  9 +++-
>  2 files changed, 39 insertions(+), 19 deletions(-)
> 
> diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h b/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
> index 811f969cd..067ef18ba 100644
> --- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
> +++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
> @@ -9,19 +9,16 @@
>  #include "tst_test.h"
>  #include "lapi/pidfd.h"
>  
> -static inline int ioctl_pidfd_info_exit_supported(void)
> +static inline long ioctl_pidfd_get_info_supported(void)
>  {
> -	int ret;
>  	pid_t pid;
> -	int pidfd;
> -	int supported = 0;
> +	int pidfd, ret;
>  	struct pidfd_info info;
>  
> -	if (tst_kvercmp(6, 15, 0) >= 0)
> +	if (tst_kvercmp(6, 12, 0) >= 0)
>  		return 1;
>  
>  	memset(&info, 0, sizeof(struct pidfd_info));
> -	info.mask = PIDFD_INFO_EXIT;

We have to keep the PIDFD_INFO_EXIT in the mask, otherwise it will never
be set back by the kernel.

>  	pid = SAFE_FORK();
>  	if (!pid)
> @@ -31,23 +28,39 @@ static inline int ioctl_pidfd_info_exit_supported(void)
>  	SAFE_WAITPID(pid, NULL, 0);
>  
>  	ret = ioctl(pidfd, PIDFD_GET_INFO, &info);
> +	SAFE_CLOSE(pidfd);
> +
>  	if (ret == -1) {
> -		/* - ENOTTY: old kernels not implementing fs/pidfs.c:pidfd_ioctl
> -		 * - EINVAL: until v6.13 kernel
> -		 * - ESRCH: all kernels between v6.13 and v6.15
> +		/* - ENOTTY: kernel too old, ioctl(PIDFD_GET_INFO) not implemented; return -1 */
> +		if (errno == ENOTTY)
> +			return -1;
> +
> +		/* - EINVAL: ioctl(PIDFD_GET_INFO) exists but invalid args
> +		 * - ESRCH: ioctl(PIDFD_GET_INFO) exists but task already exited
> +		 * both mean supported, but info.mask is not set; return 0
>  		 */
> -		if (errno != ENOTTY &&
> -			errno != EINVAL &&
> -			errno != ESRCH)
> -			tst_brk(TBROK | TERRNO, "ioctl error");
> -	} else {
> -		if (info.mask & PIDFD_INFO_EXIT)
> -			supported = 1;
> +		if (errno == EINVAL || errno == ESRCH)
> +			return 0;

If we do not pass the PIDFD_INFO_EXIT above we will end up with ESRCH
here all the time.

Generally I do not like this code that much, since we depend on the fact
that we get ESCHR from the syscall if PIDFD_INFO_EXIT is not
implemented. Without the PIDFD_INFO_EXIT flag the pidfd_info() syscall
is supposed to work on a process before it's waited for and
PIDFD_INFO_EXIT does not work before the process is waited for, mixing
these two checks is a bit ugly.

> +		tst_brk(TBROK | TERRNO, "unexpected ioctl(PIDFD_GET_INFO) error");
>  	}
>  
> -	SAFE_CLOSE(pidfd);
> +	/* ioctl(PIDFD_GET_INFO) successful; return mask */
> +	return info.mask;
> +}
> +
> +static inline bool ioctl_pidfd_info_exit_supported(void)
> +{
> +	long mask;
> +
> +	if (tst_kvercmp(6, 15, 0) >= 0)
> +		return 1;
> +
> +	mask = ioctl_pidfd_get_info_supported();
> +	if (mask == -1)
> +		return 0;
>  
> -	return supported;
> +	return !!(mask & PIDFD_INFO_EXIT);
>  }
>  
>  #endif
> diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
> index c379717b3..871f2fe5e 100644
> --- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
> +++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
> @@ -14,7 +14,7 @@
>  #include "tst_test.h"
>  #include "lapi/pidfd.h"
>  #include "lapi/sched.h"
> -#include "lapi/ioctl.h"
> +#include "ioctl_pidfd.h"
>  
>  struct pidfd_info_invalid {
>  	uint32_t dummy;
> @@ -48,8 +48,15 @@ static void run(void)
>  	SAFE_CLOSE(pidfd);
>  }
>  
> +static void setup(void)
> +{
> +	if (ioctl_pidfd_get_info_supported() == -1)
> +		tst_brk(TCONF, "ioctl(PIDFD_GET_INFO) is not implemented");
> +}
> +
>  static struct tst_test test = {
>  	.test_all = run,
> +	.setup = setup,
>  	.forks_child = 1,
>  	.bufs = (struct tst_buffers []) {
>  		{&args, .size = sizeof(*args)},
> -- 
> 2.51.0
> 

-- 
Cyril Hrubis
chrubis@suse.cz

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH v2] Introduce ioctl_pidfd_get_info_supported() function

[Petr Vorel]

Hi Avinesh, Cyril,

...
> >  	memset(&info, 0, sizeof(struct pidfd_info));
> > -	info.mask = PIDFD_INFO_EXIT;

> We have to keep the PIDFD_INFO_EXIT in the mask, otherwise it will never
> be set back by the kernel.

+1, I'm sorry to overlook this change.

> >  	pid = SAFE_FORK();
> >  	if (!pid)
> > @@ -31,23 +28,39 @@ static inline int ioctl_pidfd_info_exit_supported(void)
> >  	SAFE_WAITPID(pid, NULL, 0);

> >  	ret = ioctl(pidfd, PIDFD_GET_INFO, &info);
> > +	SAFE_CLOSE(pidfd);
> > +
> >  	if (ret == -1) {
> > -		/* - ENOTTY: old kernels not implementing fs/pidfs.c:pidfd_ioctl
> > -		 * - EINVAL: until v6.13 kernel
> > -		 * - ESRCH: all kernels between v6.13 and v6.15
> > +		/* - ENOTTY: kernel too old, ioctl(PIDFD_GET_INFO) not implemented; return -1 */
> > +		if (errno == ENOTTY)
> > +			return -1;
> > +
> > +		/* - EINVAL: ioctl(PIDFD_GET_INFO) exists but invalid args
> > +		 * - ESRCH: ioctl(PIDFD_GET_INFO) exists but task already exited
> > +		 * both mean supported, but info.mask is not set; return 0
> >  		 */
> > -		if (errno != ENOTTY &&
> > -			errno != EINVAL &&
> > -			errno != ESRCH)
> > -			tst_brk(TBROK | TERRNO, "ioctl error");
> > -	} else {
> > -		if (info.mask & PIDFD_INFO_EXIT)
> > -			supported = 1;
> > +		if (errno == EINVAL || errno == ESRCH)
> > +			return 0;

> If we do not pass the PIDFD_INFO_EXIT above we will end up with ESRCH
> here all the time.

+1 (again, I'm sorry to overlook it).

> Generally I do not like this code that much, since we depend on the fact
> that we get ESCHR from the syscall if PIDFD_INFO_EXIT is not
> implemented. Without the PIDFD_INFO_EXIT flag the pidfd_info() syscall
> is supposed to work on a process before it's waited for and
> PIDFD_INFO_EXIT does not work before the process is waited for, mixing
> these two checks is a bit ugly.

Avinesh, I'm sorry, I see my suggestion to reuse code to detect PIDFD_INFO_EXIT
for checking PIDFD_GET_INFO was not a good idea. It'll be clearer to have them
separated.

BTW although ioctl_pidfd_info_exit_supported() should be kept as is, it does not
harm to use bool for it. But that's not related to this fix.

Kind regards,
Petr

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Re: [LTP] [PATCH v2] Introduce ioctl_pidfd_get_info_supported() function

[Cyril Hrubis]

Hi!
> > Generally I do not like this code that much, since we depend on the fact
> > that we get ESCHR from the syscall if PIDFD_INFO_EXIT is not
> > implemented. Without the PIDFD_INFO_EXIT flag the pidfd_info() syscall
> > is supposed to work on a process before it's waited for and
> > PIDFD_INFO_EXIT does not work before the process is waited for, mixing
> > these two checks is a bit ugly.
> 
> Avinesh, I'm sorry, I see my suggestion to reuse code to detect PIDFD_INFO_EXIT
> for checking PIDFD_GET_INFO was not a good idea. It'll be clearer to have them
> separated.

We went through a few iteration of the check with Andrea before we
arrived at a working version. Sometimes detecting features gets
complex...

-- 
Cyril Hrubis
chrubis@suse.cz

-- 
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[LTP] [PATCH v3] Introduce ioctl_pidfd_get_info_supported() function

[Avinesh Kumar]

use this routine in ioctl_pidfd05 before proceeding with the test

Suggested-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Avinesh Kumar <akumar@suse.de>
---
 testcases/kernel/syscalls/ioctl/ioctl_pidfd.h | 42 +++++++++++++++++++
 .../kernel/syscalls/ioctl/ioctl_pidfd05.c     |  9 +++-
 2 files changed, 50 insertions(+), 1 deletion(-)

diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h b/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
index 811f969cd..29bc60cfb 100644
--- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
+++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
@@ -9,6 +9,48 @@
 #include "tst_test.h"
 #include "lapi/pidfd.h"
 
+static inline bool ioctl_pidfd_get_info_supported(void)
+{
+	pid_t pid;
+	int pidfd, ret;
+	int supported = 0;
+	struct pidfd_info info;
+
+	if (tst_kvercmp(6, 12, 0) >= 0)
+		return 1;
+
+	memset(&info, 0, sizeof(struct pidfd_info));
+
+	pid = SAFE_FORK();
+	if (!pid)
+		exit(100);
+
+	pidfd = SAFE_PIDFD_OPEN(pid, 0);
+	SAFE_WAITPID(pid, NULL, 0);
+
+	ret = ioctl(pidfd, PIDFD_GET_INFO, &info);
+	SAFE_CLOSE(pidfd);
+
+	if (ret == -1) {
+		/* - ENOTTY: kernel too old, ioctl(PIDFD_GET_INFO) not implemented */
+		if (errno == ENOTTY)
+			supported = 0;
+
+		/* - EINVAL: ioctl(PIDFD_GET_INFO) exists but args invalid
+		 * - ESRCH: ioctl(PIDFD_GET_INFO) exists but task already exited
+		 * supported in both cases, but info.mask not set
+		 */
+		else if (errno == EINVAL || errno == ESRCH)
+			supported = 1;
+		else
+			tst_brk(TBROK | TERRNO, "unexpected ioctl(PIDFD_GET_INFO) error");
+	} else {
+		supported = 1;
+	}
+
+	return supported;
+}
+
 static inline int ioctl_pidfd_info_exit_supported(void)
 {
 	int ret;
diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
index c379717b3..d20c6f074 100644
--- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
+++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
@@ -14,7 +14,7 @@
 #include "tst_test.h"
 #include "lapi/pidfd.h"
 #include "lapi/sched.h"
-#include "lapi/ioctl.h"
+#include "ioctl_pidfd.h"
 
 struct pidfd_info_invalid {
 	uint32_t dummy;
@@ -48,8 +48,15 @@ static void run(void)
 	SAFE_CLOSE(pidfd);
 }
 
+static void setup(void)
+{
+	if (!ioctl_pidfd_get_info_supported())
+		tst_brk(TCONF, "ioctl(PIDFD_GET_INFO) is not implemented");
+}
+
 static struct tst_test test = {
 	.test_all = run,
+	.setup = setup,
 	.forks_child = 1,
 	.bufs = (struct tst_buffers []) {
 		{&args, .size = sizeof(*args)},
-- 
2.51.0


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Re: [LTP] [PATCH v3] Introduce ioctl_pidfd_get_info_supported() function

[Petr Vorel]

Hi Avinesh,

> use this routine in ioctl_pidfd05 before proceeding with the test

Reviewed-by: Petr Vorel <pvorel@suse.cz>

BTW, when testing on 6.11, I got:
ioctl_pidfd05.c:45: TFAIL: ioctl(pidfd, PIDFD_GET_INFO, NULL) expected EINVAL: ENOTTY (25)

Which is error unrelated to this patch, it's from original.
196988f7d1 ("Add ioctl_pidfd05 test")

Doc in ioctl_pidfd_info_exit_supported() is clear about it:
		/* - ENOTTY: old kernels not implementing fs/pidfs.c:pidfd_ioctl
		 * - EINVAL: until v6.13 kernel
		 * - ESRCH: all kernels between v6.13 and v6.15
		 */

But test happily ignores the fact :).

@Cyril do we want to fix it? Do we want to check for kernel versions or we just
take any of these values?

Kind regards,
Petr

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Re: [LTP] [PATCH v3] Introduce ioctl_pidfd_get_info_supported() function

[Cyril Hrubis]

Hi!
> +static inline bool ioctl_pidfd_get_info_supported(void)
> +{
> +	pid_t pid;
> +	int pidfd, ret;
> +	int supported = 0;
> +	struct pidfd_info info;
> +
> +	if (tst_kvercmp(6, 12, 0) >= 0)
> +		return 1;
> +
> +	memset(&info, 0, sizeof(struct pidfd_info));
> +
> +	pid = SAFE_FORK();
> +	if (!pid)
> +		exit(100);
> +
> +	pidfd = SAFE_PIDFD_OPEN(pid, 0);
> +	SAFE_WAITPID(pid, NULL, 0);

Again, please do not waitpid before the PIDFD_GET_INFO ioctl(). If you
do that it has no chance of succeeding.

From fs/pidfd.c:

...
        task = get_pid_task(pid, PIDTYPE_PID);
        if (!task) {
                /*
                 * If the task has already been reaped, only exit
                 * information is available
                 */
                if (!(mask & PIDFD_INFO_EXIT))
                        return -ESRCH;

                goto copy_out;
        }
...

We have to do the ioctl() first and the waitpid() second for this case.

And if we do so we don't have to check the errno at all, the call will
just succeed in case that it's supported.

> +	ret = ioctl(pidfd, PIDFD_GET_INFO, &info);
> +	SAFE_CLOSE(pidfd);
> +
> +	if (ret == -1) {
> +		/* - ENOTTY: kernel too old, ioctl(PIDFD_GET_INFO) not implemented */
> +		if (errno == ENOTTY)
> +			supported = 0;
> +
> +		/* - EINVAL: ioctl(PIDFD_GET_INFO) exists but args invalid
> +		 * - ESRCH: ioctl(PIDFD_GET_INFO) exists but task already exited
> +		 * supported in both cases, but info.mask not set
> +		 */
> +		else if (errno == EINVAL || errno == ESRCH)
> +			supported = 1;
> +		else
> +			tst_brk(TBROK | TERRNO, "unexpected ioctl(PIDFD_GET_INFO) error");
> +	} else {
> +		supported = 1;
> +	}
> +
> +	return supported;
> +}
> +
>  static inline int ioctl_pidfd_info_exit_supported(void)
>  {
>  	int ret;
> diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
> index c379717b3..d20c6f074 100644
> --- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
> +++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
> @@ -14,7 +14,7 @@
>  #include "tst_test.h"
>  #include "lapi/pidfd.h"
>  #include "lapi/sched.h"
> -#include "lapi/ioctl.h"
> +#include "ioctl_pidfd.h"
>  
>  struct pidfd_info_invalid {
>  	uint32_t dummy;
> @@ -48,8 +48,15 @@ static void run(void)
>  	SAFE_CLOSE(pidfd);
>  }
>  
> +static void setup(void)
> +{
> +	if (!ioctl_pidfd_get_info_supported())
> +		tst_brk(TCONF, "ioctl(PIDFD_GET_INFO) is not implemented");
> +}
> +
>  static struct tst_test test = {
>  	.test_all = run,
> +	.setup = setup,
>  	.forks_child = 1,
>  	.bufs = (struct tst_buffers []) {
>  		{&args, .size = sizeof(*args)},
> -- 
> 2.51.0
> 

-- 
Cyril Hrubis
chrubis@suse.cz

-- 
Mailing list info: https://lists.linux.it/listinfo/ltp

Re: [LTP] [PATCH v3] Introduce ioctl_pidfd_get_info_supported() function

[Cyril Hrubis]

Hi!
> > use this routine in ioctl_pidfd05 before proceeding with the test
> 
> Reviewed-by: Petr Vorel <pvorel@suse.cz>
> 
> BTW, when testing on 6.11, I got:
> ioctl_pidfd05.c:45: TFAIL: ioctl(pidfd, PIDFD_GET_INFO, NULL) expected EINVAL: ENOTTY (25)

This is exactly what this patch is trying to address. Not sure what went
wrong there.

> Which is error unrelated to this patch, it's from original.
> 196988f7d1 ("Add ioctl_pidfd05 test")
> 
> Doc in ioctl_pidfd_info_exit_supported() is clear about it:
> 		/* - ENOTTY: old kernels not implementing fs/pidfs.c:pidfd_ioctl
> 		 * - EINVAL: until v6.13 kernel
> 		 * - ESRCH: all kernels between v6.13 and v6.15
> 		 */

And the pidfd_info_supported() tries to address that by returning zero
on ENOTTY.

-- 
Cyril Hrubis
chrubis@suse.cz

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[LTP] [PATCH v4] Introduce ioctl_pidfd_get_info_supported() function

[Avinesh Kumar]

Check if ioctl(PIDFD_GET_INFO) is implemented or not
before proceeding in ioctl_pidfd05 test

Suggested-by: Cyril Hrubis <chrubis@suse.cz>
Suggested-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Avinesh Kumar <akumar@suse.de>
---
 testcases/kernel/syscalls/ioctl/ioctl_pidfd.h | 28 +++++++++++++++++++
 .../kernel/syscalls/ioctl/ioctl_pidfd05.c     |  9 +++++-
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h b/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
index 811f969cd..b785d8043 100644
--- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
+++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
@@ -9,6 +9,34 @@
 #include "tst_test.h"
 #include "lapi/pidfd.h"
 
+static inline bool ioctl_pidfd_get_info_supported(void)
+{
+	pid_t pid;
+	int pidfd, ret;
+	int supported = 0;
+	struct pidfd_info info;
+
+	if (tst_kvercmp(6, 13, 0) >= 0)
+		return 1;
+
+	memset(&info, 0, sizeof(struct pidfd_info));
+
+	pid = SAFE_FORK();
+	if (!pid)
+		exit(100);
+
+	pidfd = SAFE_PIDFD_OPEN(pid, 0);
+
+	ret = ioctl(pidfd, PIDFD_GET_INFO, &info);
+	SAFE_WAITPID(pid, NULL, 0);
+
+	if (ret != -1)
+		supported = 1;
+
+	SAFE_CLOSE(pidfd);
+	return supported;
+}
+
 static inline int ioctl_pidfd_info_exit_supported(void)
 {
 	int ret;
diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
index c379717b3..d20c6f074 100644
--- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
+++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
@@ -14,7 +14,7 @@
 #include "tst_test.h"
 #include "lapi/pidfd.h"
 #include "lapi/sched.h"
-#include "lapi/ioctl.h"
+#include "ioctl_pidfd.h"
 
 struct pidfd_info_invalid {
 	uint32_t dummy;
@@ -48,8 +48,15 @@ static void run(void)
 	SAFE_CLOSE(pidfd);
 }
 
+static void setup(void)
+{
+	if (!ioctl_pidfd_get_info_supported())
+		tst_brk(TCONF, "ioctl(PIDFD_GET_INFO) is not implemented");
+}
+
 static struct tst_test test = {
 	.test_all = run,
+	.setup = setup,
 	.forks_child = 1,
 	.bufs = (struct tst_buffers []) {
 		{&args, .size = sizeof(*args)},
-- 
2.51.0


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Re: [LTP] [PATCH v3] Introduce ioctl_pidfd_get_info_supported() function

[Avinesh Kumar]

Hi Cyril,

On Wednesday, September 24, 2025 10:34:43 AM CEST Cyril Hrubis wrote:
> Hi!
> > +static inline bool ioctl_pidfd_get_info_supported(void)
> > +{
> > +	pid_t pid;
> > +	int pidfd, ret;
> > +	int supported = 0;
> > +	struct pidfd_info info;
> > +
> > +	if (tst_kvercmp(6, 12, 0) >= 0)
> > +		return 1;
> > +
> > +	memset(&info, 0, sizeof(struct pidfd_info));
> > +
> > +	pid = SAFE_FORK();
> > +	if (!pid)
> > +		exit(100);
> > +
> > +	pidfd = SAFE_PIDFD_OPEN(pid, 0);
> > +	SAFE_WAITPID(pid, NULL, 0);
> 
> Again, please do not waitpid before the PIDFD_GET_INFO ioctl(). If you
> do that it has no chance of succeeding.
> 
> From fs/pidfd.c:
> 
> ...
>         task = get_pid_task(pid, PIDTYPE_PID);
>         if (!task) {
>                 /*
>                  * If the task has already been reaped, only exit
>                  * information is available
>                  */
>                 if (!(mask & PIDFD_INFO_EXIT))
>                         return -ESRCH;
> 
>                 goto copy_out;
>         }
> ...
> 
> We have to do the ioctl() first and the waitpid() second for this case.
> 
> And if we do so we don't have to check the errno at all, the call will
> just succeed in case that it's supported.
> 
Thank you for your patience explaining this one repeatedly. I read through
the iterations of these new tests in ML to get better understanding of
checking the feature detection. I have sent another revision.
I have also changed the kernel version check from 6.12 to 6.13 as that's
where I see pidfd_info() implementation.


Regards,
Avinesh




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Re: [LTP] [PATCH v4] Introduce ioctl_pidfd_get_info_supported() function

[Li Wang via ltp]

On Thu, Sep 25, 2025 at 4:29 AM Avinesh Kumar <akumar@suse.de> wrote:

> Check if ioctl(PIDFD_GET_INFO) is implemented or not
> before proceeding in ioctl_pidfd05 test
>
> Suggested-by: Cyril Hrubis <chrubis@suse.cz>
> Suggested-by: Petr Vorel <pvorel@suse.cz>
> Signed-off-by: Avinesh Kumar <akumar@suse.de>
>

This version looks much more elegant.

Reviewed-by: Li Wang <liwang@redhat.com>

---
>  testcases/kernel/syscalls/ioctl/ioctl_pidfd.h | 28 +++++++++++++++++++
>  .../kernel/syscalls/ioctl/ioctl_pidfd05.c     |  9 +++++-
>  2 files changed, 36 insertions(+), 1 deletion(-)
>
> diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
> b/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
> index 811f969cd..b785d8043 100644
> --- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
> +++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
> @@ -9,6 +9,34 @@
>  #include "tst_test.h"
>  #include "lapi/pidfd.h"
>
> +static inline bool ioctl_pidfd_get_info_supported(void)
> +{
> +       pid_t pid;
> +       int pidfd, ret;
> +       int supported = 0;
> +       struct pidfd_info info;
> +
> +       if (tst_kvercmp(6, 13, 0) >= 0)
> +               return 1;
> +
> +       memset(&info, 0, sizeof(struct pidfd_info));
> +
> +       pid = SAFE_FORK();
> +       if (!pid)
> +               exit(100);
> +
> +       pidfd = SAFE_PIDFD_OPEN(pid, 0);
> +
> +       ret = ioctl(pidfd, PIDFD_GET_INFO, &info);
> +       SAFE_WAITPID(pid, NULL, 0);
> +
> +       if (ret != -1)
> +               supported = 1;
> +
> +       SAFE_CLOSE(pidfd);
> +       return supported;
> +}
> +
>  static inline int ioctl_pidfd_info_exit_supported(void)
>  {
>         int ret;
> diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
> b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
> index c379717b3..d20c6f074 100644
> --- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
> +++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
> @@ -14,7 +14,7 @@
>  #include "tst_test.h"
>  #include "lapi/pidfd.h"
>  #include "lapi/sched.h"
> -#include "lapi/ioctl.h"
> +#include "ioctl_pidfd.h"
>
>  struct pidfd_info_invalid {
>         uint32_t dummy;
> @@ -48,8 +48,15 @@ static void run(void)
>         SAFE_CLOSE(pidfd);
>  }
>
> +static void setup(void)
> +{
> +       if (!ioctl_pidfd_get_info_supported())
> +               tst_brk(TCONF, "ioctl(PIDFD_GET_INFO) is not implemented");
> +}
> +
>  static struct tst_test test = {
>         .test_all = run,
> +       .setup = setup,
>         .forks_child = 1,
>         .bufs = (struct tst_buffers []) {
>                 {&args, .size = sizeof(*args)},
> --
> 2.51.0
>
>
> --
> Mailing list info: https://lists.linux.it/listinfo/ltp
>
>

-- 
Regards,
Li Wang

-- 
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Re: [LTP] [PATCH v4] Introduce ioctl_pidfd_get_info_supported() function

[Li Wang via ltp]

On Thu, Sep 25, 2025 at 4:29 AM Avinesh Kumar <akumar@suse.de> wrote:

> Check if ioctl(PIDFD_GET_INFO) is implemented or not
> before proceeding in ioctl_pidfd05 test
>
> Suggested-by: Cyril Hrubis <chrubis@suse.cz>
> Suggested-by: Petr Vorel <pvorel@suse.cz>
> Signed-off-by: Avinesh Kumar <akumar@suse.de>
> ---
>  testcases/kernel/syscalls/ioctl/ioctl_pidfd.h | 28 +++++++++++++++++++
>  .../kernel/syscalls/ioctl/ioctl_pidfd05.c     |  9 +++++-
>  2 files changed, 36 insertions(+), 1 deletion(-)
>
> diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
> b/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
> index 811f969cd..b785d8043 100644
> --- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
> +++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
> @@ -9,6 +9,34 @@
>  #include "tst_test.h"
>  #include "lapi/pidfd.h"
>
> +static inline bool ioctl_pidfd_get_info_supported(void)
>

The return type should be int, but not bool.



> +{
> +       pid_t pid;
> +       int pidfd, ret;
> +       int supported = 0;
> +       struct pidfd_info info;
> +
> +       if (tst_kvercmp(6, 13, 0) >= 0)
> +               return 1;
> +
> +       memset(&info, 0, sizeof(struct pidfd_info));
> +
> +       pid = SAFE_FORK();
> +       if (!pid)
> +               exit(100);
> +
> +       pidfd = SAFE_PIDFD_OPEN(pid, 0);
> +
> +       ret = ioctl(pidfd, PIDFD_GET_INFO, &info);
> +       SAFE_WAITPID(pid, NULL, 0);
> +
> +       if (ret != -1)
> +               supported = 1;
> +
> +       SAFE_CLOSE(pidfd);
> +       return supported;
> +}
> +
>  static inline int ioctl_pidfd_info_exit_supported(void)
>  {
>         int ret;
> diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
> b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
> index c379717b3..d20c6f074 100644
> --- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
> +++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
> @@ -14,7 +14,7 @@
>  #include "tst_test.h"
>  #include "lapi/pidfd.h"
>  #include "lapi/sched.h"
> -#include "lapi/ioctl.h"
> +#include "ioctl_pidfd.h"
>
>  struct pidfd_info_invalid {
>         uint32_t dummy;
> @@ -48,8 +48,15 @@ static void run(void)
>         SAFE_CLOSE(pidfd);
>  }
>
> +static void setup(void)
> +{
> +       if (!ioctl_pidfd_get_info_supported())
> +               tst_brk(TCONF, "ioctl(PIDFD_GET_INFO) is not implemented");
> +}
> +
>  static struct tst_test test = {
>         .test_all = run,
> +       .setup = setup,
>         .forks_child = 1,
>         .bufs = (struct tst_buffers []) {
>                 {&args, .size = sizeof(*args)},
> --
> 2.51.0
>
>
> --
> Mailing list info: https://lists.linux.it/listinfo/ltp
>
>

-- 
Regards,
Li Wang

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Re: [LTP] [PATCH v4] Introduce ioctl_pidfd_get_info_supported() function

[Cyril Hrubis]

Hi!
Looks good now:

Reviewed-by: Cyril Hrubis <chrubis@suse.cz>

-- 
Cyril Hrubis
chrubis@suse.cz

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[LTP] [PATCH v5] Introduce ioctl_pidfd_get_info_supported() function

[Avinesh Kumar]

Check if ioctl(PIDFD_GET_INFO) is implemented or not
before proceeding in ioctl_pidfd05 test

Reviewed-by: Li Wang <liwang@redhat.com>
Reviewed-by: Cyril Hrubis <chrubis@suse.cz>
Suggested-by: Cyril Hrubis <chrubis@suse.cz>
Suggested-by: Petr Vorel <pvorel@suse.cz>
Signed-off-by: Avinesh Kumar <akumar@suse.de>
---
 testcases/kernel/syscalls/ioctl/ioctl_pidfd.h | 28 +++++++++++++++++++
 .../kernel/syscalls/ioctl/ioctl_pidfd05.c     |  9 +++++-
 2 files changed, 36 insertions(+), 1 deletion(-)

diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h b/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
index 811f969cd..2740284f7 100644
--- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
+++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd.h
@@ -9,6 +9,34 @@
 #include "tst_test.h"
 #include "lapi/pidfd.h"
 
+static inline int ioctl_pidfd_get_info_supported(void)
+{
+	pid_t pid;
+	int pidfd, ret;
+	int supported = 0;
+	struct pidfd_info info;
+
+	if (tst_kvercmp(6, 13, 0) >= 0)
+		return 1;
+
+	memset(&info, 0, sizeof(struct pidfd_info));
+
+	pid = SAFE_FORK();
+	if (!pid)
+		exit(100);
+
+	pidfd = SAFE_PIDFD_OPEN(pid, 0);
+
+	ret = ioctl(pidfd, PIDFD_GET_INFO, &info);
+	SAFE_WAITPID(pid, NULL, 0);
+
+	if (ret != -1)
+		supported = 1;
+
+	SAFE_CLOSE(pidfd);
+	return supported;
+}
+
 static inline int ioctl_pidfd_info_exit_supported(void)
 {
 	int ret;
diff --git a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
index c379717b3..d20c6f074 100644
--- a/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
+++ b/testcases/kernel/syscalls/ioctl/ioctl_pidfd05.c
@@ -14,7 +14,7 @@
 #include "tst_test.h"
 #include "lapi/pidfd.h"
 #include "lapi/sched.h"
-#include "lapi/ioctl.h"
+#include "ioctl_pidfd.h"
 
 struct pidfd_info_invalid {
 	uint32_t dummy;
@@ -48,8 +48,15 @@ static void run(void)
 	SAFE_CLOSE(pidfd);
 }
 
+static void setup(void)
+{
+	if (!ioctl_pidfd_get_info_supported())
+		tst_brk(TCONF, "ioctl(PIDFD_GET_INFO) is not implemented");
+}
+
 static struct tst_test test = {
 	.test_all = run,
+	.setup = setup,
 	.forks_child = 1,
 	.bufs = (struct tst_buffers []) {
 		{&args, .size = sizeof(*args)},
-- 
2.51.0


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Re: [LTP] [PATCH v5] Introduce ioctl_pidfd_get_info_supported() function

[Petr Vorel]

Hi Avinesh,

...
> +static inline int ioctl_pidfd_get_info_supported(void)

nit: I liked more the previous version v4, where 'bool' was used.
Actually both functions could use 'bool', but I'm perfectly ok with 'int'.

Reviewed-by: Petr Vorel <pvorel@suse.cz>

Kind regards,
Petr

> +{
> +	pid_t pid;
> +	int pidfd, ret;
> +	int supported = 0;
> +	struct pidfd_info info;
> +
> +	if (tst_kvercmp(6, 13, 0) >= 0)
> +		return 1;
> +
> +	memset(&info, 0, sizeof(struct pidfd_info));
> +
> +	pid = SAFE_FORK();
> +	if (!pid)
> +		exit(100);
> +
> +	pidfd = SAFE_PIDFD_OPEN(pid, 0);
> +
> +	ret = ioctl(pidfd, PIDFD_GET_INFO, &info);
> +	SAFE_WAITPID(pid, NULL, 0);
> +
> +	if (ret != -1)
> +		supported = 1;
> +
> +	SAFE_CLOSE(pidfd);
> +	return supported;
> +}

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Re: [LTP] [PATCH v5] Introduce ioctl_pidfd_get_info_supported() function

[Petr Vorel]

Hi all,

Fix merged, thank you!

Kind regards,
Petr

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