Skip site navigation (1)Skip section navigation (2) 
Date:      Thu, 10 Oct 2019 05:49:55 +0000
From:      <Zhichao1.Li@dell.com>
To:        <freebsd-fs@freebsd.org>, <freebsd-drivers@freebsd.org>
Cc:        <Shunchao.Hu@dell.com>
Subject:   a issue about getting a devfs node's fullpath 
Message-ID:  <c6d34bd0b4114bee956b0af6d680a67f@KULX13MDC103.APAC.DELL.COM>
next in thread | raw e-mail | index | archive | help 
Dear freebsd developers
I know you're swamped, so I'll be brief.
I am trying to get a node's full under /dev by calling the function 'vn_ful=
lpath', when dealing with things like '/dev/null' or '/dev/usb/1.0.1', it w=
orks well.
However when dealing a node under more than 2 sub directories (e.g. /dev/bu=
s/usb/001/002)  which I made by calling 'make_dev_s' , it goes a little bit=
 different, I got a string "/dev/bus/usb/bus/usb/001/002"
And I found the function 'devfs_vptocnp' gets the string wrongly when deali=
ng multi slashes path string, I have remark the code as followed and put so=
me comments
would you please take a look, and tell me what the purpose this func pass t=
he string that way?
static int
devfs_vptocnp(struct vop_vptocnp_args *ap)
{
        struct vnode *vp =3D ap->a_vp;
        struct vnode **dvp =3D ap->a_vpp;
        struct devfs_mount *dmp;
        char *buf =3D ap->a_buf;
        int *buflen =3D ap->a_buflen;
        struct devfs_dirent *dd, *de;
        int i, error;

        dmp =3D VFSTODEVFS(vp->v_mount);

        error =3D devfs_populate_vp(vp);
        if (error !=3D 0)
                return (error);

        i =3D *buflen;
        dd =3D vp->v_data;

        if (vp->v_type =3D=3D VCHR) {
                i -=3D strlen(dd->de_cdp->cdp_c.si_name);
                if (i < 0) {
                        error =3D ENOMEM;
                        goto finished;
                }
                bcopy(dd->de_cdp->cdp_c.si_name, buf + i,
                    strlen(dd->de_cdp->cdp_c.si_name));
               /*
* when dealing with VCHR
                * the element 'si_name' already
                * holds the full path string
                * except rootdir, why not just go
                * to the rootdir?
                */
                de =3D dd->de_dir;
        } else if (vp->v_type =3D=3D VDIR) {
                if (dd =3D=3D dmp->dm_rootdir) {
                        *dvp =3D vp;
                        vref(*dvp);
                        goto finished;
                }
                i -=3D dd->de_dirent->d_namlen;
                if (i < 0) {
error =3D ENOMEM;
                             goto finished;
                }
                bcopy(dd->de_cdp->cdp_c.si_name, buf + i,
                    strlen(dd->de_cdp->cdp_c.si_name));
                de =3D dd->de_dir;
        } else if (vp->v_type =3D=3D VDIR) {
                if (dd =3D=3D dmp->dm_rootdir) {
                        *dvp =3D vp;
                        vref(*dvp);
                        goto finished;
                }
                i -=3D dd->de_dirent->d_namlen;
                if (i < 0) {
                        error =3D ENOMEM;
                        goto finished;
                }
                bcopy(dd->de_dirent->d_name, buf + i,
                    dd->de_dirent->d_namlen);
                de =3D dd;
        } else {
                error =3D ENOENT;
                goto finished;
        }
        *buflen =3D i;
        de =3D devfs_parent_dirent(de);
        if (de =3D=3D NULL) {
                error =3D ENOENT;
                goto finished;
        }
        mtx_lock(&devfs_de_interlock);
        *dvp =3D de->de_vnode;
        if (*dvp !=3D NULL) {
                VI_LOCK(*dvp);
                mtx_unlock(&devfs_de_interlock);
                vholdl(*dvp);
                VI_UNLOCK(*dvp);
                vref(*dvp);
                vdrop(*dvp);
        } else {
               mtx_unlock(&devfs_de_interlock);
error =3D ENOENT;
        }
finished:
        sx_xunlock(&dmp->dm_lock);
        return (error);
}

Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?c6d34bd0b4114bee956b0af6d680a67f>