Date: Fri, 11 Oct 2019 02:23:14 +0000 From: <Zhichao1.Li@dell.com> To: <kib@freebsd.org> Cc: <freebsd-fs@freebsd.org>, <freebsd-drivers@freebsd.org>, <Shunchao.Hu@dell.com> Subject: RE: a issue about getting a devfs node's fullpath Message-ID: <54b7173c96df43689de04f848ca86de6@KULX13MDC103.APAC.DELL.COM> In-Reply-To: <20191010153932.GO44691@kib.kiev.ua> References: <c6d34bd0b4114bee956b0af6d680a67f@KULX13MDC103.APAC.DELL.COM> <20191010153932.GO44691@kib.kiev.ua>
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Hello
Thank you for your time
Unfortunately it does not work, how about this way?
--- a/src/sys/fs/devfs/devfs_vnops.c
+++ b/src/sys/fs/devfs/devfs_vnops.c
@@ -293,7 +293,14 @@ devfs_vptocnp(struct vop_vptocnp_args *ap)
}
bcopy(dd->de_cdp->cdp_c.si_name, buf + i,
strlen(dd->de_cdp->cdp_c.si_name));
- de = dd->de_dir;
+ /*
+ * when dealing with VCHR
+ * the element 'si_name' already
+ * holds the full path string
+ * except rootdir, so just go
+ * to the rootdir
+ */
+ de = dmp->dm_rootdir;
} else if (vp->v_type == VDIR) {
if (dd == dmp->dm_rootdir) {
*dvp = vp;
@@ -307,13 +314,17 @@ devfs_vptocnp(struct vop_vptocnp_args *ap)
}
bcopy(dd->de_dirent->d_name, buf + i,
dd->de_dirent->d_namlen);
- de = dd;
+ /*
+ * when dealing with VDIR
+ * get its parent
+ */
+ de = devfs_parent_dirent(dd);
} else {
error = ENOENT;
goto finished;
}
*buflen = i;
- de = devfs_parent_dirent(de);
+ /*no need to get another parent*/
if (de == NULL) {
error = ENOENT;
goto finished;
another thing is this func is called by many modules, I want to ensure modifying the func this way will not impact other modules and not bring some bugs, would you be so kind to help me out?
thank you
-----Original Message-----
From: Konstantin Belousov <kib@freebsd.org>
Sent: Thursday, October 10, 2019 11:40 PM
To: Li, Zhichao1 <Zhichao_Li1@Dell.com>
Cc: freebsd-fs@freebsd.org; freebsd-drivers@freebsd.org; Hu, Shunchao <Shunchao_Hu@Dell.com>
Subject: Re: a issue about getting a devfs node's fullpath
[EXTERNAL EMAIL]
On Thu, Oct 10, 2019 at 05:49:55AM +0000, Zhichao1.Li@dell.com wrote:
> 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_fullpath', when dealing with things like '/dev/null' or '/dev/usb/1.0.1', it works well.
> However when dealing a node under more than 2 sub directories (e.g. /dev/bus/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
> dealing multi slashes path string, I have remark the code as followed and put some comments would you please take a look, and tell me what the purpose this func pass the string that way?
Try this. Not tested.
diff --git a/sys/fs/devfs/devfs_vnops.c b/sys/fs/devfs/devfs_vnops.c index 3b80c68e309..f20b466d88b 100644
--- a/sys/fs/devfs/devfs_vnops.c
+++ b/sys/fs/devfs/devfs_vnops.c
@@ -284,38 +284,27 @@ devfs_vptocnp(struct vop_vptocnp_args *ap)
if (error != 0)
return (error);
- i = *buflen;
+ if (vp->v_type != VCHR && vp->v_type != VDIR) {
+ error = ENOENT;
+ goto finished;
+ }
+
dd = vp->v_data;
+ if (vp->v_type == VDIR && dd == dmp->dm_rootdir) {
+ *dvp = vp;
+ vref(*dvp);
+ goto finished;
+ }
- if (vp->v_type == VCHR) {
- i -= strlen(dd->de_cdp->cdp_c.si_name);
- if (i < 0) {
- error = ENOMEM;
- goto finished;
- }
- bcopy(dd->de_cdp->cdp_c.si_name, buf + i,
- strlen(dd->de_cdp->cdp_c.si_name));
- de = dd->de_dir;
- } else if (vp->v_type == VDIR) {
- if (dd == dmp->dm_rootdir) {
- *dvp = vp;
- vref(*dvp);
- goto finished;
- }
- i -= dd->de_dirent->d_namlen;
- if (i < 0) {
- error = ENOMEM;
- goto finished;
- }
- bcopy(dd->de_dirent->d_name, buf + i,
- dd->de_dirent->d_namlen);
- de = dd;
- } else {
- error = ENOENT;
+ i = *buflen;
+ i -= dd->de_dirent->d_namlen;
+ if (i < 0) {
+ error = ENOMEM;
goto finished;
}
+ bcopy(dd->de_dirent->d_name, buf + i, dd->de_dirent->d_namlen);
*buflen = i;
- de = devfs_parent_dirent(de);
+ de = devfs_parent_dirent(dd);
if (de == NULL) {
error = ENOENT;
goto finished;
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