[Patch v2] Add access function attributes to grp and shadow headers

[Siddhesh Poyarekar]

On 11/03/2022 04:01, Steve Grubb via Libc-alpha wrote:
> This patch adds access function attributes to the re-entrant functions
> in grp.h and shadow headers.
> 
> v2 - add missing parenthesis
> 
> ---

This patch showed up as failed in patchwork CI:

https://patchwork.sourceware.org/project/glibc/patch/4708166.GXAFRqVoOG@x2/
https://www.delorie.com/trybots/32bit/7828/misc-tst-bz21269.out

However the failure is unrelated to this change.  I ran tst-bz21269 in a 
loop with and without this patch and found that it occasionally timed 
out.  I've filed a separate bug for this:

https://sourceware.org/bugzilla/show_bug.cgi?id=28961

LGTM.  I'll push once my test run completes.

Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>

>   grp/grp.h         |   12 ++++++++----
>   gshadow/gshadow.h |   12 ++++++++----
>   shadow/shadow.h   |   12 ++++++++----
>   3 files changed, 24 insertions(+), 12 deletions(-)
> ---
> diff -urp glibc-2.35.9000-111-g2bbc694df2.orig/grp/grp.h glibc-2.35.9000-111-g2bbc694df2/grp/grp.h
> --- glibc-2.35.9000-111-g2bbc694df2.orig/grp/grp.h	2022-02-28 10:47:38.000000000 -0500
> +++ glibc-2.35.9000-111-g2bbc694df2/grp/grp.h	2022-03-10 11:56:18.733069367 -0500
> @@ -130,7 +130,8 @@ extern struct group *getgrnam (const cha
>   # ifdef __USE_GNU
>   extern int getgrent_r (struct group *__restrict __resultbuf,
>   		       char *__restrict __buffer, size_t __buflen,
> -		       struct group **__restrict __result);
> +		       struct group **__restrict __result)
> +	__attr_access ((__write_only__, 2, 3));
>   # endif
>   
>   /* Search for an entry with a matching group ID.
> @@ -139,7 +140,8 @@ extern int getgrent_r (struct group *__r
>      marked with __THROW.  */
>   extern int getgrgid_r (__gid_t __gid, struct group *__restrict __resultbuf,
>   		       char *__restrict __buffer, size_t __buflen,
> -		       struct group **__restrict __result);
> +		       struct group **__restrict __result)
> +	__attr_access ((__write_only__, 3, 4));
>   
>   /* Search for an entry with a matching group name.
>   
> @@ -148,7 +150,8 @@ extern int getgrgid_r (__gid_t __gid, st
>   extern int getgrnam_r (const char *__restrict __name,
>   		       struct group *__restrict __resultbuf,
>   		       char *__restrict __buffer, size_t __buflen,
> -		       struct group **__restrict __result);
> +		       struct group **__restrict __result)
> +	__attr_access ((__write_only__, 3, 4));
>   
>   # ifdef	__USE_MISC
>   /* Read a group entry from STREAM.  This function is not standardized
> @@ -161,7 +164,8 @@ extern int getgrnam_r (const char *__res
>   extern int fgetgrent_r (FILE *__restrict __stream,
>   			struct group *__restrict __resultbuf,
>   			char *__restrict __buffer, size_t __buflen,
> -			struct group **__restrict __result);
> +			struct group **__restrict __result)
> +	__attr_access ((__write_only__, 3, 4));
>   # endif
>   
>   #endif	/* POSIX or reentrant */
> diff -urp glibc-2.35.9000-111-g2bbc694df2.orig/gshadow/gshadow.h glibc-2.35.9000-111-g2bbc694df2/gshadow/gshadow.h
> --- glibc-2.35.9000-111-g2bbc694df2.orig/gshadow/gshadow.h	2022-02-28 10:47:38.000000000 -0500
> +++ glibc-2.35.9000-111-g2bbc694df2/gshadow/gshadow.h	2022-03-10 12:10:00.417407391 -0500
> @@ -108,19 +108,23 @@ extern int putsgent (const struct sgrp *
>      or due to the implementation they are cancellation points and
>      therefore not marked with __THROW.  */
>   extern int getsgent_r (struct sgrp *__result_buf, char *__buffer,
> -		       size_t __buflen, struct sgrp **__result);
> +		       size_t __buflen, struct sgrp **__result)
> +	__attr_access ((__write_only__, 2, 3));
>   
>   extern int getsgnam_r (const char *__name, struct sgrp *__result_buf,
>   		       char *__buffer, size_t __buflen,
> -		       struct sgrp **__result);
> +		       struct sgrp **__result)
> +	__attr_access ((__write_only__, 3, 4));
>   
>   extern int sgetsgent_r (const char *__string, struct sgrp *__result_buf,
>   			char *__buffer, size_t __buflen,
> -			struct sgrp **__result);
> +			struct sgrp **__result)
> +	__attr_access ((__write_only__, 3, 4));
>   
>   extern int fgetsgent_r (FILE *__stream, struct sgrp *__result_buf,
>   			char *__buffer, size_t __buflen,
> -			struct sgrp **__result);
> +			struct sgrp **__result)
> +	__attr_access ((__write_only__, 3, 4));
>   #endif	/* misc */
>   
>   __END_DECLS
> diff -urp glibc-2.35.9000-111-g2bbc694df2.orig/shadow/shadow.h glibc-2.35.9000-111-g2bbc694df2/shadow/shadow.h
> --- glibc-2.35.9000-111-g2bbc694df2.orig/shadow/shadow.h	2022-02-28 10:47:38.000000000 -0500
> +++ glibc-2.35.9000-111-g2bbc694df2/shadow/shadow.h	2022-03-10 11:59:17.647530571 -0500
> @@ -122,19 +122,23 @@ extern int putspent (const struct spwd *
>      or due to the implementation they are cancellation points and
>      therefore not marked with __THROW.  */
>   extern int getspent_r (struct spwd *__result_buf, char *__buffer,
> -		       size_t __buflen, struct spwd **__result);
> +		       size_t __buflen, struct spwd **__result)
> +	__attr_access ((__write_only__, 2, 3));
>   
>   extern int getspnam_r (const char *__name, struct spwd *__result_buf,
>   		       char *__buffer, size_t __buflen,
> -		       struct spwd **__result);
> +		       struct spwd **__result)
> +	__attr_access ((__write_only__, 3, 4));
>   
>   extern int sgetspent_r (const char *__string, struct spwd *__result_buf,
>   			char *__buffer, size_t __buflen,
> -			struct spwd **__result);
> +			struct spwd **__result)
> +	__attr_access ((__write_only__, 3, 4));
>   
>   extern int fgetspent_r (FILE *__stream, struct spwd *__result_buf,
>   			char *__buffer, size_t __buflen,
> -			struct spwd **__result);
> +			struct spwd **__result)
> +	__attr_access ((__write_only__, 3, 4));
>   #endif	/* misc */
>   
>   
> 
> 
>