From 96f3e42ce2c9de14b3e9a1de338ed639c1c8b596 Mon Sep 17 00:00:00 2001
From: mav <mav@FreeBSD.org>
Date: Thu, 24 May 2012 14:07:44 +0000
Subject: MFprojects/zfsd: Revamp the CAM enclosure services driver. This
 updated driver uses an in-kernel daemon to track state changes and publishes
 physical path location information\for disk elements into the CAM device
 database.

Sponsored by:   Spectra Logic Corporation
Sponsored by:   iXsystems, Inc.
Submitted by:   gibbs, will, mav
---
 sys/fs/devfs/devfs_vnops.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 45 insertions(+)

(limited to 'sys/fs')

diff --git a/sys/fs/devfs/devfs_vnops.c b/sys/fs/devfs/devfs_vnops.c
index 4a58a42..8cbfb03 100644
--- a/sys/fs/devfs/devfs_vnops.c
+++ b/sys/fs/devfs/devfs_vnops.c
@@ -1266,8 +1266,53 @@ static int
 devfs_readlink(struct vop_readlink_args *ap)
 {
 	struct devfs_dirent *de;
+	struct cdev_priv *cdp;
 
 	de = ap->a_vp->v_data;
+	cdp = de->de_cdp;
+
+	if (cdp != NULL && (cdp->cdp_c.si_flags & SI_ALIAS) != 0) {
+		struct devfs_mount *dmp;
+		struct prison *pr;
+		char *mp;
+		int mp_len;
+		int pr_path_len;
+		int err;
+
+		/*
+		 * For device aliases, construct an absolute symlink (to
+		 * shorten its length and avoid the ugliness of a relative
+		 * link) by prepending the fully qualified path to the root
+		 * of this devfs.  For a non-jailed process, the devfs root
+		 * is our mount point.  For a jailed process, we must remove
+		 * any jail prefix in our mount point so that our response
+		 * matches the user process's world view.
+		 */
+		dmp = VFSTODEVFS(ap->a_vp->v_mount);
+		mp = dmp->dm_mount->mnt_stat.f_mntonname;
+		mp_len = strlen(mp);
+
+		pr = ap->a_cred->cr_prison;
+		pr_path_len = strlen(pr->pr_path);
+
+		if (strncmp(pr->pr_path, mp, pr_path_len) == 0
+		 && mp[pr_path_len] == '/') {
+			mp += pr_path_len;
+			mp_len -= pr_path_len;
+		}
+
+		err = uiomove(mp, mp_len, ap->a_uio);
+		if (err != 0)
+			return (err);
+
+		/*
+		 * Devfs cannot be the root file system, so its
+		 * mount point must always be terminated by a '/'.
+		 */
+		err = uiomove("/", 1, ap->a_uio);
+		if (err != 0)
+			return (err);
+	}
 	return (uiomove(de->de_symlink, strlen(de->de_symlink), ap->a_uio));
 }
 
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