linux(4): Move translate_vnhook_major_minor() into the Linux common module

(cherry picked from commit 6072eea0c375fc3ab0cf5bb494c75d1beac7b8ba)

1 files changed, 26 insertions, 0 deletions

diff --git a/sys/compat/linux/linux_util.c b/sys/compat/linux/linux_util.c
index 2a21fdc10bd7..5995ac5e18af 100644
--- a/sys/compat/linux/linux_util.c
+++ b/sys/compat/linux/linux_util.c
@@ -42,6 +42,7 @@ __FBSDID("$FreeBSD$");
 #include <sys/malloc.h>
 #include <sys/namei.h>
 #include <sys/proc.h>
+#include <sys/stat.h>
 #include <sys/syscallsubr.h>
 #include <sys/vnode.h>
 
@@ -225,6 +226,31 @@ linux_vn_get_major_minor(const struct vnode *vp, int *major, int *minor)
 	return (error);
 }
 
+void
+translate_vnhook_major_minor(struct vnode *vp, struct stat *sb)
+{
+	int major, minor;
+
+	if (vn_isdisk(vp)) {
+		sb->st_mode &= ~S_IFMT;
+		sb->st_mode |= S_IFBLK;
+	}
+
+	/*
+	 * Return the same st_dev for every devfs instance.  The reason
+	 * for this is to work around an idiosyncrasy of glibc getttynam()
+	 * implementation: it checks whether st_dev returned for fd 0
+	 * is the same as st_dev returned for the target of /proc/self/fd/0
+	 * symlink, and with linux chroots having their own devfs instance,
+	 * the check will fail if you chroot into it.
+	 */
+	if (rootdevmp != NULL && vp->v_mount->mnt_vfc == rootdevmp->mnt_vfc)
+		sb->st_dev = rootdevmp->mnt_stat.f_fsid.val[0];
+
+	if (linux_vn_get_major_minor(vp, &major, &minor) == 0)
+		sb->st_rdev = (major << 8 | minor);
+}
+
 char *
 linux_get_char_devices(void)
 {