[libvirt] [PATCHv2 1/2] util: Don't fail virGetUserIDByName when user not found

[Peter Krempa]

On 12/06/12 15:37, Christophe Fergeau wrote:
> virGetUserIDByName is documented as returning 1 if the username
> cannot be found. getpwnam_r is documented as returning:
> « 0 or ENOENT or ESRCH or EBADF or EPERM or ...  The given name
> or uid was not found. »
>   and that:
> « The formulation given above under "RETURN VALUE" is from POSIX.1-2001.
> It  does  not  call  "not  found"  an error, hence does not specify what
> value errno might have in this situation.  But that makes it impossible to
> recognize errors.  One might argue that according to POSIX errno should be
> left unchanged if an entry is not found.  Experiments on various UNIX-like
> systems shows that lots of different values occur in this situation: 0,
> ENOENT, EBADF, ESRCH, EWOULDBLOCK, EPERM and probably others. »
>
> virGetUserIDByName returns an error when the return value of getpwnam_r
> is non-0. However on my RHEL system, getpwnam_r returns ENOENT when the
> requested user cannot be found, which then causes virGetUserID not
> to behave as documented (it returns an error instead of falling back
> to parsing the passed-in value as an uid).
>
> This commit makes virGetUserIDByName only report an error when errno
> is set to one of the values in the posix description of getpwnam_r
> (which are the same as the ones described in the manpage on my system).
> ---
>   src/util/util.c | 15 ++++++++++++---
>   1 file changed, 12 insertions(+), 3 deletions(-)
>
> diff --git a/src/util/util.c b/src/util/util.c
> index 2fd0f2c..b50563b 100644
> --- a/src/util/util.c
> +++ b/src/util/util.c
> @@ -2531,9 +2531,18 @@ virGetUserIDByName(const char *name, uid_t *uid)
>       }
>
>       if (rc != 0) {
> -        virReportSystemError(rc, _("Failed to get user record for name '%s'"),
> -                             name);
> -        goto cleanup;
> +       /* We explicitly test for the known error values returned by
> +        * getpwnam_r as the manpage says:
> +        * ERRORS
> +        *   0 or ENOENT or ESRCH or EBADF or EPERM or ...
> +        *         The given name or uid was not found.
> +        */
> +       if ((rc == EINTR) || (rc == EIO) || (rc == EMFILE)
> +           || (rc == ENFILE) || (rc == ENOMEM)) {

We usualy write the operator at the end of the previous line of a linebreak.


> +           virReportSystemError(rc, _("Failed to get user record for name '%s'"),
> +                                name);
> +           goto cleanup;
> +       }
>       }
>
>       if (!pw) {
>

ACK with that change.

Peter