[rhel7-branch 1/5] anaconda-lib.sh: add tell_user() and dev_is_cdrom()

[dashea]

From: Will Woods

Add a couple of utility functions:

* tell_user() sends a message to the log and the screen via plymouth; if
  plymouth isn't running we send it to the console instead.

* dev_is_cdrom() tells you whether the given device is a CDROM
  (according to udev).

(cherry picked from commit abfa908d089d18ce8d72ac818b62b33a1a12647a)
---
 dracut/anaconda-lib.sh | 20 ++++++++++++++++++++
 1 file changed, 20 insertions(+)

diff --git a/dracut/anaconda-lib.sh b/dracut/anaconda-lib.sh
index 9e74e3d..7a46058 100755
--- a/dracut/anaconda-lib.sh
+++ b/dracut/anaconda-lib.sh
@@ -165,6 +165,26 @@ when_any_cdrom_appears() {
       >> $rulesfile
 }

+plymouth_running() {
+    type plymouth >/dev/null 2>&1 && plymouth --ping 2>/dev/null
+}
+
+# print something to the display (and put it in the log so we know what's up)
+tell_user() {
+    if plymouth_running; then
+        # NOTE: if we're doing graphical splash but we don't have all the
+        # font-rendering libraries, no message will appear.
+        plymouth display-message --text="$*"
+        echo "$*"     # this goes to journal only
+    else
+        echo "$*" >&2 # this goes to journal+console
+    fi
+}
+
+dev_is_cdrom() {
+    udevadm info --query=property --name=$1 | grep -q 'ID_CDROM=1'
+}
+
 # dracut doesn't bring up the network unless:
 #   a) $netroot is set (i.e. you have a network root device), or
 #   b) /tmp/net.ifaces exists.