[PATCH] docs: proc.rst: comm: mention the included NUL

[PATCH] docs: proc.rst: comm: mention the included NUL

[Christoph Anton Mitterer]

Indicate that the actual value will be one character less.

Signed-off-by: Christoph Anton Mitterer <mail@christoph.anton.mitterer.name>
---
 Documentation/filesystems/proc.rst | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index 104c6d047d9b..41b9be923519 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -1899,8 +1899,8 @@ For more information on mount propagation see:
 These files provide a method to access a task's comm value. It also allows for
 a task to set its own or one of its thread siblings comm value. The comm value
 is limited in size compared to the cmdline value, so writing anything longer
-then the kernel's TASK_COMM_LEN (currently 16 chars) will result in a truncated
-comm value.
+then the kernel's TASK_COMM_LEN (currently 16 chars, including the null
+terminator) will result in a truncated comm value.
 
 
 3.7	/proc/<pid>/task/<tid>/children - Information about task children
-- 
2.43.0

[PATCH v2 0/1] docs: proc.rst: comm: mention the included NUL

[Christoph Anton Mitterer]

Hey.

V1 of the patch explained matters purely from `TASK_COMM_LEN`’s PoV, where the
last character is the null terminator.

But the documentation is more about the file `comm`, where the last character is
a LF character.


V2: Addresses the above by also explaining that the null terminator is printed
    as LF in the file.


Choose whichever of the two you prefer, I don't mind.

Thanks,
Chris.

[PATCH v2 1/1] docs: proc.rst: comm: mention the included NUL

[Christoph Anton Mitterer]

Indicate that the actual value will be one character less.

Signed-off-by: Christoph Anton Mitterer <mail@christoph.anton.mitterer.name>
---
 Documentation/filesystems/proc.rst | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
index 104c6d047d9b..c0e92a056079 100644
--- a/Documentation/filesystems/proc.rst
+++ b/Documentation/filesystems/proc.rst
@@ -1899,8 +1899,9 @@ For more information on mount propagation see:
 These files provide a method to access a task's comm value. It also allows for
 a task to set its own or one of its thread siblings comm value. The comm value
 is limited in size compared to the cmdline value, so writing anything longer
-then the kernel's TASK_COMM_LEN (currently 16 chars) will result in a truncated
-comm value.
+then the kernel's TASK_COMM_LEN (currently 16 chars, including the null
+terminator, which is printed as the line feed character in the file) will result
+in a truncated comm value.
 
 
 3.7	/proc/<pid>/task/<tid>/children - Information about task children
-- 
2.43.0

Re: [PATCH v2 1/1] docs: proc.rst: comm: mention the included NUL

[Jonathan Corbet]

Christoph Anton Mitterer <mail@christoph.anton.mitterer.name> writes:

> Indicate that the actual value will be one character less.
>
> Signed-off-by: Christoph Anton Mitterer <mail@christoph.anton.mitterer.name>
> ---
>  Documentation/filesystems/proc.rst | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/filesystems/proc.rst b/Documentation/filesystems/proc.rst
> index 104c6d047d9b..c0e92a056079 100644
> --- a/Documentation/filesystems/proc.rst
> +++ b/Documentation/filesystems/proc.rst
> @@ -1899,8 +1899,9 @@ For more information on mount propagation see:
>  These files provide a method to access a task's comm value. It also allows for
>  a task to set its own or one of its thread siblings comm value. The comm value
>  is limited in size compared to the cmdline value, so writing anything longer
> -then the kernel's TASK_COMM_LEN (currently 16 chars) will result in a truncated
> -comm value.
> +then the kernel's TASK_COMM_LEN (currently 16 chars, including the null
> +terminator, which is printed as the line feed character in the file) will result
> +in a truncated comm value.

I don't understand the line-feed comment at all; printed by whom?

I think I'll just apply the first version, which explained the situation
well enough.

Thanks,

jon

Re: [PATCH v2 1/1] docs: proc.rst: comm: mention the included NUL

[Christoph Anton Mitterer]

On Thu, 2024-02-08 at 15:47 -0700, Jonathan Corbet wrote:
> I don't understand the line-feed comment at all; printed by whom?

I mean when reading the file /proc/.../comm, then the string seems to
have a trailing newline (LF).

Perhaps something like "provided" or "given" would have been a better
word, but not really perfect either.
And "written" or "stored" would have also been wrong IMO.


> I think I'll just apply the first version, which explained the
> situation
> well enough.

I'd also think it's enough, which is why I had even written, that you
may pick whichever you like better.


Thanks,
Chris.