df: Rewrite virt-df in C.

I have diffed the output from the original virt-df with this
new version, and they agree very closely.  Some differences:

 - Old virt-df have a divide-by-zero error in cases where the
   number of used inodes was 0.  New virt-df fixes this.

 - New virt-df uses gnulib human_readable library which displays
   numbers to 3 significant figures for -h output (old version
   used an ad hoc function).

1 files changed, 72 insertions, 0 deletions

diff --git a/df/test-virt-df.sh b/df/test-virt-df.sh
new file mode 100755
index 00000000..6878327d
--- /dev/null
+++ b/df/test-virt-df.sh
@@ -0,0 +1,72 @@
+#!/bin/bash -
+
+export LANG=C
+set -e
+
+# Run virt-df.
+output=$(./virt-df ../images/fedora.img)
+
+# Check title is the first line.
+if [[ ! $output =~ ^Filesystem.* ]]; then
+    echo "$0: error: no title line"
+    exit 1
+fi
+
+# Check 6 lines (title line + 5 * filesystems).
+if [ $(echo "$output" | wc -l) -ne 6 ]; then
+    echo "$0: error: not all filesystems were found"
+    exit 1
+fi
+
+# Check /dev/VG/LV[1-3] and /dev/VG/Root were found.
+if [[ ! $output =~ fedora.img:/dev/VG/LV1 ]]; then
+    echo "$0: error: filesystem /dev/VG/LV1 was not found"
+    exit 1
+fi
+if [[ ! $output =~ fedora.img:/dev/VG/LV2 ]]; then
+    echo "$0: error: filesystem /dev/VG/LV2 was not found"
+    exit 1
+fi
+if [[ ! $output =~ fedora.img:/dev/VG/LV3 ]]; then
+    echo "$0: error: filesystem /dev/VG/LV3 was not found"
+    exit 1
+fi
+if [[ ! $output =~ fedora.img:/dev/VG/Root ]]; then
+    echo "$0: error: filesystem /dev/VG/Root was not found"
+    exit 1
+fi
+
+# Check /dev/sda1 was found.  Might be called /dev/vda1.
+if [[ ! $output =~ fedora.img:/dev/[hsv]da1 ]]; then
+    echo "$0: error: filesystem /dev/VG/sda1 was not found"
+    exit 1
+fi
+
+# This is what df itself prints for these filesystems (determined
+# by running the test image under virt-rescue):
+#
+# ><rescue> df -h
+# Filesystem            Size  Used Avail Use% Mounted on
+# /dev/dm-1              31M   28K   30M   1% /sysroot/lv1
+# /dev/dm-2              31M  395K   29M   2% /sysroot/lv2
+# /dev/dm-3              62M  144K   59M   1% /sysroot/lv3
+# ><rescue> df -i
+# Filesystem            Inodes   IUsed   IFree IUse% Mounted on
+# /dev/dm-1               8192      11    8181    1% /sysroot/lv1
+# /dev/dm-2               8192      11    8181    1% /sysroot/lv2
+# /dev/dm-3              16384      11   16373    1% /sysroot/lv3
+# ><rescue> df
+# Filesystem           1K-blocks      Used Available Use% Mounted on
+# /dev/dm-1                31728        28     30064   1% /sysroot/lv1
+# /dev/dm-2                31729       395     29696   2% /sysroot/lv2
+# /dev/dm-3                63472       144     60052   1% /sysroot/lv3
+#
+# Only test plain 'df' output at the moment (XXX).
+
+if [ "$(echo "$output" | sort | awk '/VG.LV[123]/ { print $2 " " $3 " " $4 " " $5 }')" != \
+"31728 28 30064 1%
+31729 395 29696 2%
+63472 144 60052 1%" ]; then
+    echo "$0: error: output of virt-df did not match expected (df) output"
+    exit 1
+fi