Re: [LTP] [PATCH] lib/tst_uid_gid.c: fix checking return value errors about getpwuid_r/getgrgid_r

[Stanislav Kholmanskikh <stanislav.kholmanskikh@oracle.com>]

Hi!

On 02/20/2014 06:10 AM, Zeng Linggang wrote:
> When we  call getgrgid_r()  to  verify whether the corresponding gid is
> existent, if not, getgrgid_r() will return 0 or ENOENT or ESRCH or
> EBADF or EPERM...
>
> But tst_get_unused_gid() only check return value 0, this is not complete.
> For example, if the gid is not existent, getgrgid_r() in RHEL7 beta will
> return ENOENT, which will cause tst_get_unused_gid failed incorrectly.
> This is the same for getpwuid_r().

Thank you.

I was puzzled by these two sentences in the getgrgid_r man (RHEL6):
"If no matching  group  record was  found,  these  functions  return  0 
  and  store  NULL  in *result.  In case of error, an error number is
returned, and NULL is stored in *result."

Maybe update the man page according with 
http://www.gnu.org/software/libc/manual/html_node/Lookup-Group.html. I 
think that there the return values are described more clear.

What do you think?

>
> We should make tst_get_unused_uid/tst_get_unused_gid check all the possible
> return value.
>
> Signed-off-by: Zeng Linggang <zenglg.jy@cn.fujitsu.com>
> ---
>   lib/tst_uid_gid.c | 31 +++++++++++++++++++++++++++----
>   1 file changed, 27 insertions(+), 4 deletions(-)
>
> diff --git a/lib/tst_uid_gid.c b/lib/tst_uid_gid.c
> index 3ba1ad6..a835c38 100644
> --- a/lib/tst_uid_gid.c
> +++ b/lib/tst_uid_gid.c
> @@ -16,6 +16,7 @@
>    * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
>    */
>
> +#include <errno.h>
>   #include <grp.h>
>   #include <limits.h>
>   #include <pwd.h>
> @@ -44,10 +45,21 @@ uid_t tst_get_unused_uid(void)
>   		s = getpwuid_r(uid, &pwd, buf, bufsize, &result);
>   		if (result == NULL) {
>   			free(buf);
> -			if (s == 0)
> +			/*
> +			 * When the given name or gid was not found, getgrgid_r
> +			 * may return 0 or ENOENT or ESRCH or EBADF or EPERM
> +			 * or ...
> +			 */
> +			switch (s) {
> +			case 0:
> +			case ENOENT:
> +			case ESRCH:
> +			case EBADF:
> +			case EPERM:
>   				return uid;
> -			else
> +			default:
>   				return -1;
> +			}
>   		}
>   	}
>
> @@ -76,10 +88,21 @@ gid_t tst_get_unused_gid(void)
>   		s = getgrgid_r(gid, &grp, buf, bufsize, &result);
>   		if (result == NULL) {
>   			free(buf);
> -			if (s == 0)
> +			/*
> +			 * When the given name or gid was not found, getgrgid_r
> +			 * may return 0 or ENOENT or ESRCH or EBADF or EPERM
> +			 * or ...
> +			 */
> +			switch (s) {
> +			case 0:
> +			case ENOENT:
> +			case ESRCH:
> +			case EBADF:
> +			case EPERM:
>   				return gid;
> -			else
> +			default:
>   				return -1;
> +			}
>   		}
>   	}
>
>

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