Re: [LTP] [PATCH v2] safe_macros.c: set umask to 0 within safe_mount

[Petr Vorel <pvorel@suse.cz>]

Hi Wei, all,

> When system's default umask is 0077, this will trigger following issues:
> chdir01.c:100: TFAIL: nobody: chdir("subdir") returned unexpected value -1: EACCES (13)

> Suggested-by: Martin Doucha <mdoucha@suse.cz>
> Signed-off-by: Wei Gao <wegao@suse.com>

> ---
>  doc/C-Test-API.asciidoc | 4 +++-
>  lib/safe_macros.c       | 3 +++
>  2 files changed, 6 insertions(+), 1 deletion(-)

> diff --git a/doc/C-Test-API.asciidoc b/doc/C-Test-API.asciidoc
> index 08a76c403..81067b12b 100644
> --- a/doc/C-Test-API.asciidoc
> +++ b/doc/C-Test-API.asciidoc
> @@ -2460,7 +2460,9 @@ with 'open()' or 'creat()' etc, the mode specified as the last parameter *is
>  not* the mode the file is created with. The mode depends on current 'umask()'
>  settings which may clear some of the bits. If your test depends on specific
>  file permissions you need either to change umask to 0 or 'chmod()' the file
> -afterwards or use 'SAFE_TOUCH()' that does the 'chmod()' for you.
> +afterwards or use 'SAFE_TOUCH()' that does the 'chmod()' for you. SAFE_MOUNT
s/SAFE_MOUNT/'SAFE_MOUNT()'/

> +also does similar action such as setting umask(0) and then restoring the
> +original value.

I'm not sure about the wording. Maybe:

Temporarily clearing umask with 'umask(0)' is done before mounting in
'SAFE_MOUNT()' and before creating a new subdir in the cgroup in 'cgroup_dir_mk()'.

(based on my patch
https://lore.kernel.org/ltp/20240307232511.228396-1-pvorel@suse.cz/).

It could be changed before merge.

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

Kind regards,
Petr

>  2.2 access()
>  ~~~~~~~~~~~~
> diff --git a/lib/safe_macros.c b/lib/safe_macros.c
> index 951e1b064..109268587 100644
> --- a/lib/safe_macros.c
> +++ b/lib/safe_macros.c
> @@ -913,7 +913,10 @@ int safe_mount(const char *file, const int lineno, void (*cleanup_fn)(void),
>  	 * the kernel's NTFS driver doesn't have proper write support.
>  	 */
>  	if (!filesystemtype || strcmp(filesystemtype, "ntfs")) {
> +		mode_t old_umask = umask(0);
> +
>  		rval = mount(source, target, filesystemtype, mountflags, data);
> +		umask(old_umask);
>  		if (!rval)
>  			return 0;
>  	}

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