Libguestfs - Jul 2011 - [PATCH 0/2] Add /dev/mapper/* paths to guestfish tab completion.

When you open a LUKS device, you have to associate it with a "raw"
device mapper device (eg. /dev/mapper/lukstest).  Previously there has
been no way through the API to list such devices after they have been
created.  Also they are not revealed when you tab-complete /dev paths
in guestfish.

These two patches fix this.  The first patch adds a new API called
guestfs_list_dm_devices which lists all device mapper devices that are
not associated with LVs.  We don't want to return LVs here because we
prefer to use the "/dev/VG/LV" notation for these throughout the rest
of the API.

The second patch extends guestfish so that tab completion includes
/dev/mapper paths.

Future work:

Returning filesystems on opened LUKS devices from
guestfs_list_filesystems.

Rich.

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
libguestfs lets you edit virtual machines.  Supports shell scripting,
bindings from many languages.  http://libguestfs.org

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-p2v converts physical machines to virtual machines.  Boot with a
live CD or over the network (PXE) and turn machines into Xen guests.
http://et.redhat.com/~rjones/virt-p2v
-------------- next part --------------
>From 81ada70b277c4115a97ee9418f131591dc07e290 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones at redhat.com>
Date: Tue, 12 Jul 2011 13:26:25 +0100
Subject: [PATCH 1/2] New API: list-dm-devices (RHBZ#688062).

List device mapper devices.
---
 daemon/lvm.c                   |   80 ++++++++++++++++++++++++++++-
 generator/generator_actions.ml |   18 ++++++-
 regressions/Makefile.am        |    1 +
 regressions/test-luks-list.sh  |  111 ++++++++++++++++++++++++++++++++++++++++
 src/MAX_PROC_NR                |    2 +-
 5 files changed, 209 insertions(+), 3 deletions(-)
 create mode 100755 regressions/test-luks-list.sh

diff --git a/daemon/lvm.c b/daemon/lvm.c
index dbca20b..eaa6bce 100644
--- a/daemon/lvm.c
+++ b/daemon/lvm.c
@@ -1,5 +1,5 @@
 /* libguestfs - the guestfsd daemon
- * Copyright (C) 2009 Red Hat Inc.
+ * Copyright (C) 2009-2011 Red Hat Inc.
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -24,6 +24,7 @@
 #include <string.h>
 #include <unistd.h>
 #include <sys/stat.h>
+#include <dirent.h>
 
 #include "daemon.h"
 #include "c-ctype.h"
@@ -763,3 +764,80 @@ do_lvm_canonical_lv_name (const char *device)
 
   return canonical;             /* caller frees */
 }
+
+/* List everything in /dev/mapper which *isn't* an LV (RHBZ#688062). */
+char **
+do_list_dm_devices (void)
+{
+  char **ret = NULL;
+  int size = 0, alloc = 0;
+  struct dirent *d;
+  DIR *dir;
+  int r;
+
+  dir = opendir ("/dev/mapper");
+  if (!dir) {
+    reply_with_perror ("opendir: /dev/mapper");
+    return NULL;
+  }
+
+  while (1) {
+    errno = 0;
+    d = readdir (dir);
+    if (d == NULL) break;
+
+    /* Ignore . and .. */
+    if (STREQ (d->d_name, ".") || STREQ (d->d_name,
".."))
+      continue;
+
+    /* Ignore /dev/mapper/control which is used internally by dm. */
+    if (STREQ (d->d_name, "control"))
+      continue;
+
+    size_t len = strlen (d->d_name);
+    char devname[len+64];
+
+    snprintf (devname, len+64, "/dev/mapper/%s", d->d_name);
+
+    /* Ignore dm devices which are LVs. */
+    r = lv_canonical (devname, NULL);
+    if (r == -1) {
+      free_stringslen (ret, size);
+      closedir (dir);
+      return NULL;
+    }
+    if (r)
+      continue;
+
+    /* Not an LV, so add it. */
+    if (add_string (&ret, &size, &alloc, devname) == -1) {
+      closedir (dir);
+      return NULL;
+    }
+  }
+
+  /* Did readdir fail? */
+  if (errno != 0) {
+    reply_with_perror ("readdir: /dev/mapper");
+    free_stringslen (ret, size);
+    closedir (dir);
+    return NULL;
+  }
+
+  /* Close the directory handle. */
+  if (closedir (dir) == -1) {
+    reply_with_perror ("closedir: /dev/mapper");
+    free_stringslen (ret, size);
+    return NULL;
+  }
+
+  /* Sort the output (may be empty). */
+  if (ret != NULL)
+    sort_strings (ret, size);
+
+  /* NULL-terminate the list. */
+  if (add_string (&ret, &size, &alloc, NULL) == -1)
+    return NULL;
+
+  return ret;
+}
diff --git a/generator/generator_actions.ml b/generator/generator_actions.ml
index 54cdd15..aedbeda 100644
--- a/generator/generator_actions.ml
+++ b/generator/generator_actions.ml
@@ -5574,7 +5574,10 @@ encrypted to the underlying C<device> respectively.
 
 If this block device contains LVM volume groups, then
 calling C<guestfs_vgscan> followed by C<guestfs_vg_activate_all>
-will make them visible.");
+will make them visible.
+
+Use C<guestfs_list_dm_devices> to list all device mapper
+devices.");
 
   ("luks_open_ro", (RErr, [Device "device"; Key
"key"; String "mapname"], []), 258, [Optional
"luks"],
    [],
@@ -5986,6 +5989,19 @@ If required, C<trans=virtio> will be automatically
added to the options.
 Any other options required can be passed in the optional C<options>
 parameter.");
 
+  ("list_dm_devices", (RStringList "devices", [], []), 287,
[],
+   [],
+   "list device mapper devices",
+   "\
+List all device mapper devices.
+
+The returned list contains C</dev/mapper/*> devices, eg. ones created
+by a previous call to C<guestfs_luks_open>.
+
+Device mapper devices which correspond to logical volumes are I<not>
+returned in this list.  Call C<guestfs_lvs> if you want to list logical
+volumes.");
+
 ]
 
 let all_functions = non_daemon_functions @ daemon_functions
diff --git a/regressions/Makefile.am b/regressions/Makefile.am
index 9c181bd..fada841 100644
--- a/regressions/Makefile.am
+++ b/regressions/Makefile.am
@@ -45,6 +45,7 @@ TESTS = \
 	test-inspect-fstab.sh \
 	test-launch-race.pl \
 	test-luks.sh \
+	test-luks-list.sh \
 	test-lvm-filtering.sh \
 	test-lvm-mapping.pl \
 	test-noexec-stack.pl \
diff --git a/regressions/test-luks-list.sh b/regressions/test-luks-list.sh
new file mode 100755
index 0000000..9c51464
--- /dev/null
+++ b/regressions/test-luks-list.sh
@@ -0,0 +1,111 @@
+#!/bin/bash -
+# libguestfs
+# Copyright (C) 2011 Red Hat Inc.
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 of the License, or
+# (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with this program; if not, write to the Free Software
+# Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+
+# Test LUKS devices appear in the output of list-dm-devices.
+
+set -e
+
+[ -n "$SKIP_TEST_LUKS_SH" ] && {
+    echo "test-luks-list.sh skipped (environment variable set)"
+    exit 0
+}
+
+rm -f test1.img test.output
+
+../fish/guestfish --keys-from-stdin > test.output <<'EOF'
+sparse test1.img 1G
+run
+part-init /dev/sda mbr
+part-add /dev/sda p 64 1048575
+part-add /dev/sda p 1048576 -64
+
+# Create LUKS device with key "key0" in slot 0.
+luks-format /dev/sda1 0
+key0
+
+# Create some unrelated LVs.
+pvcreate /dev/sda2
+vgcreate VG /dev/sda2
+lvcreate LV1 /dev/VG 100
+lvcreate LV2 /dev/VG 200
+lvcreate LV3 /dev/VG 100
+
+# Open the device as 'lukstest'.
+luks-open /dev/sda1 lukstest
+key0
+
+# List devices, '/dev/mapper/lukstest' should appear.
+echo test 1
+list-dm-devices
+
+# Close the device.
+luks-close /dev/mapper/lukstest
+
+# List devices, '/dev/mapper/lukstest' should not appear.
+echo test 2
+list-dm-devices
+
+# Open the device again.
+luks-open /dev/sda1 lukstest
+key0
+
+# Check no LVs appear in list-dm-devices output.
+echo test 3
+list-dm-devices
+
+# Check LUKS device doesn't appear in any of the other lists.
+echo test 4
+list-devices | sed 's,^/dev/[hv]d,/dev/sd,'
+echo test 5
+list-partitions | sed 's,^/dev/[hv]d,/dev/sd,'
+echo test 6
+lvs
+echo test 7
+vgs
+echo test 8
+pvs | sed 's,^/dev/[hv]d,/dev/sd,'
+
+EOF
+
+# Expected vs actual output.
+if [ "$(cat test.output)" != "\
+test 1
+/dev/mapper/lukstest
+test 2
+test 3
+/dev/mapper/lukstest
+test 4
+/dev/sda
+test 5
+/dev/sda1
+/dev/sda2
+test 6
+/dev/VG/LV1
+/dev/VG/LV2
+/dev/VG/LV3
+test 7
+VG
+test 8
+/dev/sda2" ]; then
+    echo "test-luks-list.sh: Unexpected output from test:"
+    cat test.output
+    echo "[end of output]"
+    exit 1
+fi
+
+rm -f test1.img test.output
diff --git a/src/MAX_PROC_NR b/src/MAX_PROC_NR
index c20f657..209ac45 100644
--- a/src/MAX_PROC_NR
+++ b/src/MAX_PROC_NR
@@ -1 +1 @@
-286
+287
-- 
1.7.5.2

-- 
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
virt-df lists disk usage of guests without needing to install any
software inside the virtual machine.  Supports Linux and Windows.
http://et.redhat.com/~rjones/virt-df/
-------------- next part --------------
>From a8faf9fc808c9f64e21c397ce45f4092f3030fc7 Mon Sep 17 00:00:00 2001
From: "Richard W.M. Jones" <rjones at redhat.com>
Date: Tue, 12 Jul 2011 13:31:42 +0100
Subject: [PATCH 2/2] fish: Show device mapper device in tab completion
 (RHBZ#688062).

With this change:
><fs> luks-open /dev/vda1 lukstest
Enter key or passphrase ("key"):
><fs> ll /dev/<TAB>
/dev/mapper/lukstest  /dev/vda              /dev/vda1
---
 fish/destpaths.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/fish/destpaths.c b/fish/destpaths.c
index 5ed93ec..3c90517 100644
--- a/fish/destpaths.c
+++ b/fish/destpaths.c
@@ -155,6 +155,9 @@ complete_dest_paths_generator (const char *text, int state)
 
       strs = guestfs_lvs (g);
       APPEND_STRS_AND_FREE;
+
+      strs = guestfs_list_dm_devices (g);
+      APPEND_STRS_AND_FREE;
     }
 
     if (len < 1 || text[0] == '/') {
-- 
1.7.5.2