Move guestfs(3) and guestfish(1) man pages into subdirectories.

These manual pages have for a very long time 'lived' in the top
source directory.

Clean up this situation by moving those manual pages (plus associated
generated files) into the src/ and fish/ subdirectories respectively.

1 files changed, 1300 insertions, 0 deletions

diff --git a/src/guestfs.pod b/src/guestfs.pod
new file mode 100644
index 00000000..30759602
--- /dev/null
+++ b/src/guestfs.pod
@@ -0,0 +1,1300 @@
+=encoding utf8
+
+=head1 NAME
+
+guestfs - Library for accessing and modifying virtual machine images
+
+=head1 SYNOPSIS
+
+ #include <guestfs.h>
+ 
+ guestfs_h *handle = guestfs_create ();
+ guestfs_add_drive (handle, "guest.img");
+ guestfs_launch (handle);
+ guestfs_mount (handle, "/dev/sda1", "/");
+ guestfs_touch (handle, "/hello");
+ guestfs_sync (handle);
+ guestfs_close (handle);
+
+=head1 DESCRIPTION
+
+Libguestfs is a library for accessing and modifying guest disk images.
+Amongst the things this is good for: making batch configuration
+changes to guests, getting disk used/free statistics (see also:
+virt-df), migrating between virtualization systems (see also:
+virt-p2v), performing partial backups, performing partial guest
+clones, cloning guests and changing registry/UUID/hostname info, and
+much else besides.
+
+Libguestfs uses Linux kernel and qemu code, and can access any type of
+guest filesystem that Linux and qemu can, including but not limited
+to: ext2/3/4, btrfs, FAT and NTFS, LVM, many different disk partition
+schemes, qcow, qcow2, vmdk.
+
+Libguestfs provides ways to enumerate guest storage (eg. partitions,
+LVs, what filesystem is in each LV, etc.).  It can also run commands
+in the context of the guest.  Also you can access filesystems over FTP.
+
+Libguestfs is a library that can be linked with C and C++ management
+programs (or management programs written in OCaml, Perl, Python, Ruby, Java
+or Haskell).  You can also use it from shell scripts or the command line.
+
+You don't need to be root to use libguestfs, although obviously you do
+need enough permissions to access the disk images.
+
+Libguestfs is a large API because it can do many things.  For a gentle
+introduction, please read the L</API OVERVIEW> section next.
+
+=head1 API OVERVIEW
+
+This section provides a gentler overview of the libguestfs API.  We
+also try to group API calls together, where that may not be obvious
+from reading about the individual calls below.
+
+=head2 HANDLES
+
+Before you can use libguestfs calls, you have to create a handle.
+Then you must add at least one disk image to the handle, followed by
+launching the handle, then performing whatever operations you want,
+and finally closing the handle.  So the general structure of all
+libguestfs-using programs looks like this:
+
+ guestfs_h *handle = guestfs_create ();
+ 
+ /* Call guestfs_add_drive additional times if there are
+  * multiple disk images.
+  */
+ guestfs_add_drive (handle, "guest.img");
+ 
+ /* Most manipulation calls won't work until you've launched
+  * the handle.  You have to do this _after_ adding drives
+  * and _before_ other commands.
+  */
+ guestfs_launch (handle);
+ 
+ /* Now you can examine what partitions, LVs etc are available.
+  */
+ char **partitions = guestfs_list_partitions (handle);
+ char **logvols = guestfs_lvs (handle);
+ 
+ /* To access a filesystem in the image, you must mount it.
+  */
+ guestfs_mount (handle, "/dev/sda1", "/");
+ 
+ /* Now you can perform filesystem actions on the guest
+  * disk image.
+  */
+ guestfs_touch (handle, "/hello");
+ 
+ /* You only need to call guestfs_sync if you have made
+  * changes to the guest image.
+  */
+ guestfs_sync (handle);
+ 
+ /* Close the handle. */
+ guestfs_close (handle);
+
+The code above doesn't include any error checking.  In real code you
+should check return values carefully for errors.  In general all
+functions that return integers return C<-1> on error, and all
+functions that return pointers return C<NULL> on error.  See section
+L</ERROR HANDLING> below for how to handle errors, and consult the
+documentation for each function call below to see precisely how they
+return error indications.
+
+=head2 DISK IMAGES
+
+The image filename (C<"guest.img"> in the example above) could be a
+disk image from a virtual machine, a L<dd(1)> copy of a physical hard
+disk, an actual block device, or simply an empty file of zeroes that
+you have created through L<posix_fallocate(3)>.  Libguestfs lets you
+do useful things to all of these.
+
+You can add a disk read-only using C<guestfs_add_drive_ro>, in which
+case libguestfs won't modify the file.
+
+Be extremely cautious if the disk image is in use, eg. if it is being
+used by a virtual machine.  Adding it read-write will almost certainly
+cause disk corruption, but adding it read-only is safe.
+
+You must add at least one disk image, and you may add multiple disk
+images.  In the API, the disk images are usually referred to as
+C</dev/sda> (for the first one you added), C</dev/sdb> (for the second
+one you added), etc.
+
+Once C<guestfs_launch> has been called you cannot add any more images.
+You can call C<guestfs_list_devices> to get a list of the device
+names, in the order that you added them.  See also L</BLOCK DEVICE
+NAMING> below.
+
+=head2 MOUNTING
+
+Before you can read or write files, create directories and so on in a
+disk image that contains filesystems, you have to mount those
+filesystems using C<guestfs_mount>.  If you already know that a disk
+image contains (for example) one partition with a filesystem on that
+partition, then you can mount it directly:
+
+ guestfs_mount (handle, "/dev/sda1", "/");
+
+where C</dev/sda1> means literally the first partition (C<1>) of the
+first disk image that we added (C</dev/sda>).  If the disk contains
+Linux LVM2 logical volumes you could refer to those instead (eg. C</dev/VG/LV>).
+
+If you are given a disk image and you don't know what it contains then
+you have to find out.  Libguestfs can do that too: use
+C<guestfs_list_partitions> and C<guestfs_lvs> to list possible
+partitions and LVs, and either try mounting each to see what is
+mountable, or else examine them with C<guestfs_file>.  But you might
+find it easier to look at higher level programs built on top of
+libguestfs, in particular L<virt-inspector(1)>.
+
+To mount a disk image read-only, use C<guestfs_mount_ro>.  There are
+several other variations of the C<guestfs_mount_*> call.
+
+=head2 FILESYSTEM ACCESS AND MODIFICATION
+
+The majority of the libguestfs API consists of fairly low-level calls
+for accessing and modifying the files, directories, symlinks etc on
+mounted filesystems.  There are over a hundred such calls which you
+can find listed in detail below in this man page, and we don't even
+pretend to cover them all in this overview.
+
+Specify filenames as full paths including the mount point.
+
+For example, if you mounted a filesystem at C<"/"> and you want to
+read the file called C<"etc/passwd"> then you could do:
+
+ char *data = guestfs_cat (handle, "/etc/passwd");
+
+This would return C<data> as a newly allocated buffer containing the
+full content of that file (with some conditions: see also
+L</DOWNLOADING> below), or C<NULL> if there was an error.
+
+As another example, to create a top-level directory on that filesystem
+called C<"var"> you would do:
+
+ guestfs_mkdir (handle, "/var");
+
+To create a symlink you could do:
+
+ guestfs_ln_s (handle, "/etc/init.d/portmap",
+               "/etc/rc3.d/S30portmap");
+
+Libguestfs will reject attempts to use relative paths.  There is no
+concept of a current working directory.  Libguestfs can return errors
+in many situations: for example if the filesystem isn't writable, or
+if a file or directory that you requested doesn't exist.  If you are
+using the C API (documented here) you have to check for those error
+conditions after each call.  (Other language bindings turn these
+errors into exceptions).
+
+File writes are affected by the per-handle umask, set by calling
+C<guestfs_umask> and defaulting to 022.
+
+=head2 PARTITIONING
+
+Libguestfs contains API calls to read, create and modify partition
+tables on disk images.
+
+In the common case where you want to create a single partition
+covering the whole disk, you should use the C<guestfs_part_disk>
+call:
+
+ const char *parttype = "mbr";
+ if (disk_is_larger_than_2TB)
+   parttype = "gpt";
+ guestfs_part_disk (g, "/dev/sda", parttype);
+
+Obviously this effectively wipes anything that was on that disk image
+before.
+
+In general MBR partitions are both unnecessarily complicated and
+depend on archaic details, namely the Cylinder-Head-Sector (CHS)
+geometry of the disk.  C<guestfs_sfdiskM> can be used to
+create more complex arrangements where the relative sizes are
+expressed in megabytes instead of cylinders, which is a small win.
+C<guestfs_sfdiskM> will choose the nearest cylinder to approximate the
+requested size.  There's a lot of crazy stuff to do with IDE and
+virtio disks having different, incompatible CHS geometries, that you
+probably don't want to know about.
+
+My advice: make a single partition to cover the whole disk, then use
+LVM on top.
+
+=head2 LVM2
+
+Libguestfs provides access to a large part of the LVM2 API, such as
+C<guestfs_lvcreate> and C<guestfs_vgremove>.  It won't make much sense
+unless you familiarize yourself with the concepts of physical volumes,
+volume groups and logical volumes.
+
+This author strongly recommends reading the LVM HOWTO, online at
+L<http://tldp.org/HOWTO/LVM-HOWTO/>.
+
+=head2 DOWNLOADING
+
+Use C<guestfs_cat> to download small, text only files.  This call
+is limited to files which are less than 2 MB and which cannot contain
+any ASCII NUL (C<\0>) characters.  However it has a very simple
+to use API.
+
+C<guestfs_read_file> can be used to read files which contain
+arbitrary 8 bit data, since it returns a (pointer, size) pair.
+However it is still limited to "small" files, less than 2 MB.
+
+C<guestfs_download> can be used to download any file, with no
+limits on content or size (even files larger than 4 GB).
+
+To download multiple files, see C<guestfs_tar_out> and
+C<guestfs_tgz_out>.
+
+=head2 UPLOADING
+
+It's often the case that you want to write a file or files to the disk
+image.
+
+For small, single files, use C<guestfs_write_file>.  This call
+currently contains a bug which limits the call to plain text files
+(not containing ASCII NUL characters).
+
+To upload a single file, use C<guestfs_upload>.  This call has no
+limits on file content or size (even files larger than 4 GB).
+
+To upload multiple files, see C<guestfs_tar_in> and C<guestfs_tgz_in>.
+
+However the fastest way to upload I<large numbers of arbitrary files>
+is to turn them into a squashfs or CD ISO (see L<mksquashfs(8)> and
+L<mkisofs(8)>), then attach this using C<guestfs_add_drive_ro>.  If
+you add the drive in a predictable way (eg. adding it last after all
+other drives) then you can get the device name from
+C<guestfs_list_devices> and mount it directly using
+C<guestfs_mount_ro>.  Note that squashfs images are sometimes
+non-portable between kernel versions, and they don't support labels or
+UUIDs.  If you want to pre-build an image or you need to mount it
+using a label or UUID, use an ISO image instead.
+
+=head2 COPYING
+
+There are various different commands for copying between files and
+devices and in and out of the guest filesystem.  These are summarised
+in the table below.
+
+=over 4
+
+=item B<file> to B<file>
+
+Use L</guestfs_cp> to copy a single file, or
+L</guestfs_cp_a> to copy directories recursively.
+
+=item B<file or device> to B<file or device>
+
+Use L</guestfs_dd> which efficiently uses L<dd(1)>
+to copy between files and devices in the guest.
+
+Example: duplicate the contents of an LV:
+
+ guestfs_dd (g, "/dev/VG/Original", "/dev/VG/Copy");
+
+The destination (C</dev/VG/Copy>) must be at least as large as the
+source (C</dev/VG/Original>).
+
+=item B<file on the host> to B<file or device>
+
+Use L</guestfs_upload>.  See L</UPLOADING> above.
+
+=item B<file or device> to B<file on the host>
+
+Use L</guestfs_download>.  See L</DOWNLOADING> above.
+
+=back
+
+=head2 LISTING FILES
+
+C<guestfs_ll> is just designed for humans to read (mainly when using
+the L<guestfish(1)>-equivalent command C<ll>).
+
+C<guestfs_ls> is a quick way to get a list of files in a directory
+from programs, as a flat list of strings.
+
+C<guestfs_readdir> is a programmatic way to get a list of files in a
+directory, plus additional information about each one.  It is more
+equivalent to using the L<readdir(3)> call on a local filesystem.
+
+C<guestfs_find> can be used to recursively list files.
+
+=head2 RUNNING COMMANDS
+
+Although libguestfs is a primarily an API for manipulating files
+inside guest images, we also provide some limited facilities for
+running commands inside guests.
+
+There are many limitations to this:
+
+=over 4
+
+=item *
+
+The kernel version that the command runs under will be different
+from what it expects.
+
+=item *
+
+If the command needs to communicate with daemons, then most likely
+they won't be running.
+
+=item *
+
+The command will be running in limited memory.
+
+=item *
+
+Only supports Linux guests (not Windows, BSD, etc).
+
+=item *
+
+Architecture limitations (eg. won't work for a PPC guest on
+an X86 host).
+
+=item *
+
+For SELinux guests, you may need to enable SELinux and load policy
+first.  See L</SELINUX> in this manpage.
+
+=back
+
+The two main API calls to run commands are C<guestfs_command> and
+C<guestfs_sh> (there are also variations).
+
+The difference is that C<guestfs_sh> runs commands using the shell, so
+any shell globs, redirections, etc will work.
+
+=head2 CONFIGURATION FILES
+
+To read and write configuration files in Linux guest filesystems, we
+strongly recommend using Augeas.  For example, Augeas understands how
+to read and write, say, a Linux shadow password file or X.org
+configuration file, and so avoids you having to write that code.
+
+The main Augeas calls are bound through the C<guestfs_aug_*> APIs.  We
+don't document Augeas itself here because there is excellent
+documentation on the L<http://augeas.net/> website.
+
+If you don't want to use Augeas (you fool!) then try calling
+C<guestfs_read_lines> to get the file as a list of lines which
+you can iterate over.
+
+=head2 SELINUX
+
+We support SELinux guests.  To ensure that labeling happens correctly
+in SELinux guests, you need to enable SELinux and load the guest's
+policy:
+
+=over 4
+
+=item 1.
+
+Before launching, do:
+
+ guestfs_set_selinux (g, 1);
+
+=item 2.
+
+After mounting the guest's filesystem(s), load the policy.  This
+is best done by running the L<load_policy(8)> command in the
+guest itself:
+
+ guestfs_sh (g, "/usr/sbin/load_policy");
+
+(Older versions of C<load_policy> require you to specify the
+name of the policy file).
+
+=item 3.
+
+Optionally, set the security context for the API.  The correct
+security context to use can only be known by inspecting the
+guest.  As an example:
+
+ guestfs_setcon (g, "unconfined_u:unconfined_r:unconfined_t:s0");
+
+=back
+
+This will work for running commands and editing existing files.
+
+When new files are created, you may need to label them explicitly,
+for example by running the external command
+C<restorecon pathname>.
+
+=head2 SPECIAL CONSIDERATIONS FOR WINDOWS GUESTS
+
+Libguestfs can mount NTFS partitions.  It does this using the
+L<http://www.ntfs-3g.org/> driver.
+
+DOS and Windows still use drive letters, and the filesystems are
+always treated as case insensitive by Windows itself, and therefore
+you might find a Windows configuration file referring to a path like
+C<c:\windows\system32>.  When the filesystem is mounted in libguestfs,
+that directory might be referred to as C</WINDOWS/System32>.
+
+Drive letter mappings are outside the scope of libguestfs.  You have
+to use libguestfs to read the appropriate Windows Registry and
+configuration files, to determine yourself how drives are mapped (see
+also L<virt-inspector(1)>).
+
+Replacing backslash characters with forward slash characters is also
+outside the scope of libguestfs, but something that you can easily do.
+
+Where we can help is in resolving the case insensitivity of paths.
+For this, call C<guestfs_case_sensitive_path>.
+
+Libguestfs also provides some help for decoding Windows Registry
+"hive" files, through the library C<libhivex> which is part of
+libguestfs.  You have to locate and download the hive file(s)
+yourself, and then pass them to C<libhivex> functions.  See also the
+programs L<hivexml(1)>, L<hivexget(1)> and L<virt-win-reg(1)> for more
+help on this issue.
+
+=head2 USING LIBGUESTFS WITH OTHER PROGRAMMING LANGUAGES
+
+Although we don't want to discourage you from using the C API, we will
+mention here that the same API is also available in other languages.
+
+The API is broadly identical in all supported languages.  This means
+that the C call C<guestfs_mount(handle,path)> is
+C<$handle-E<gt>mount($path)> in Perl, C<handle.mount(path)> in Python,
+and C<Guestfs.mount handle path> in OCaml.  In other words, a
+straightforward, predictable isomorphism between each language.
+
+Error messages are automatically transformed
+into exceptions if the language supports it.
+
+We don't try to "object orientify" parts of the API in OO languages,
+although contributors are welcome to write higher level APIs above
+what we provide in their favourite languages if they wish.
+
+=over 4
+
+=item B<C++>
+
+You can use the I<guestfs.h> header file from C++ programs.  The C++
+API is identical to the C API.  C++ classes and exceptions are
+not implemented.
+
+=item B<Haskell>
+
+This is the only language binding that is incomplete.  Only calls
+which return simple integers have been bound in Haskell, and we are
+looking for help to complete this binding.
+
+=item B<Java>
+
+Full documentation is contained in the Javadoc which is distributed
+with libguestfs.
+
+=item B<OCaml>
+
+For documentation see the file C<guestfs.mli>.
+
+=item B<Perl>
+
+For documentation see L<Sys::Guestfs(3)>.
+
+=item B<Python>
+
+For documentation do:
+
+ $ python
+ >>> import guestfs
+ >>> help (guestfs)
+
+=item B<Ruby>
+
+Use the Guestfs module.  There is no Ruby-specific documentation, but
+you can find examples written in Ruby in the libguestfs source.
+
+=item B<shell scripts>
+
+For documentation see L<guestfish(1)>.
+
+=back
+
+=head1 CONNECTION MANAGEMENT
+
+=head2 guestfs_h *
+
+C<guestfs_h> is the opaque type representing a connection handle.
+Create a handle by calling C<guestfs_create>.  Call C<guestfs_close>
+to free the handle and release all resources used.
+
+For information on using multiple handles and threads, see the section
+L</MULTIPLE HANDLES AND MULTIPLE THREADS> below.
+
+=head2 guestfs_create
+
+ guestfs_h *guestfs_create (void);
+
+Create a connection handle.
+
+You have to call C<guestfs_add_drive> on the handle at least once.
+
+This function returns a non-NULL pointer to a handle on success or
+NULL on error.
+
+After configuring the handle, you have to call C<guestfs_launch>.
+
+You may also want to configure error handling for the handle.  See
+L</ERROR HANDLING> section below.
+
+=head2 guestfs_close
+
+ void guestfs_close (guestfs_h *handle);
+
+This closes the connection handle and frees up all resources used.
+
+=head1 ERROR HANDLING
+
+The convention in all functions that return C<int> is that they return
+C<-1> to indicate an error.  You can get additional information on
+errors by calling C<guestfs_last_error> and/or by setting up an error
+handler with C<guestfs_set_error_handler>.
+
+The default error handler prints the information string to C<stderr>.
+
+Out of memory errors are handled differently.  The default action is
+to call L<abort(3)>.  If this is undesirable, then you can set a
+handler using C<guestfs_set_out_of_memory_handler>.
+
+=head2 guestfs_last_error
+
+ const char *guestfs_last_error (guestfs_h *handle);
+
+This returns the last error message that happened on C<handle>.  If
+there has not been an error since the handle was created, then this
+returns C<NULL>.
+
+The lifetime of the returned string is until the next error occurs, or
+C<guestfs_close> is called.
+
+The error string is not localized (ie. is always in English), because
+this makes searching for error messages in search engines give the
+largest number of results.
+
+=head2 guestfs_set_error_handler
+
+ typedef void (*guestfs_error_handler_cb) (guestfs_h *handle,
+                                           void *data,
+                                           const char *msg);
+ void guestfs_set_error_handler (guestfs_h *handle,
+                                 guestfs_error_handler_cb cb,
+                                 void *data);
+
+The callback C<cb> will be called if there is an error.  The
+parameters passed to the callback are an opaque data pointer and the
+error message string.
+
+Note that the message string C<msg> is freed as soon as the callback
+function returns, so if you want to stash it somewhere you must make
+your own copy.
+
+The default handler prints messages on C<stderr>.
+
+If you set C<cb> to C<NULL> then I<no> handler is called.
+
+=head2 guestfs_get_error_handler
+
+ guestfs_error_handler_cb guestfs_get_error_handler (guestfs_h *handle,
+                                                     void **data_rtn);
+
+Returns the current error handler callback.
+
+=head2 guestfs_set_out_of_memory_handler
+
+ typedef void (*guestfs_abort_cb) (void);
+ int guestfs_set_out_of_memory_handler (guestfs_h *handle,
+                                        guestfs_abort_cb);
+
+The callback C<cb> will be called if there is an out of memory
+situation.  I<Note this callback must not return>.
+
+The default is to call L<abort(3)>.
+
+You cannot set C<cb> to C<NULL>.  You can't ignore out of memory
+situations.
+
+=head2 guestfs_get_out_of_memory_handler
+
+ guestfs_abort_fn guestfs_get_out_of_memory_handler (guestfs_h *handle);
+
+This returns the current out of memory handler.
+
+=head1 PATH
+
+Libguestfs needs a kernel and initrd.img, which it finds by looking
+along an internal path.
+
+By default it looks for these in the directory C<$libdir/guestfs>
+(eg. C</usr/local/lib/guestfs> or C</usr/lib64/guestfs>).
+
+Use C<guestfs_set_path> or set the environment variable
+C<LIBGUESTFS_PATH> to change the directories that libguestfs will
+search in.  The value is a colon-separated list of paths.  The current
+directory is I<not> searched unless the path contains an empty element
+or C<.>.  For example C<LIBGUESTFS_PATH=:/usr/lib/guestfs> would
+search the current directory and then C</usr/lib/guestfs>.
+
+=head1 HIGH-LEVEL API ACTIONS
+
+=head2 ABI GUARANTEE
+
+We guarantee the libguestfs ABI (binary interface), for public,
+high-level actions as outlined in this section.  Although we will
+deprecate some actions, for example if they get replaced by newer
+calls, we will keep the old actions forever.  This allows you the
+developer to program in confidence against libguestfs.
+
+@ACTIONS@
+
+=head1 STRUCTURES
+
+@STRUCTS@
+
+=head1 AVAILABILITY
+
+=head2 GROUPS OF FUNCTIONALITY IN THE APPLIANCE
+
+Using L</guestfs_available> you can test availability of
+the following groups of functions.  This test queries the
+appliance to see if the appliance you are currently using
+supports the functionality.
+
+@AVAILABILITY@
+
+=head2 SINGLE CALLS AT COMPILE TIME
+
+If you need to test whether a single libguestfs function is
+available at compile time, we recommend using build tools
+such as autoconf or cmake.  For example in autotools you could
+use:
+
+ AC_CHECK_LIB([guestfs],[guestfs_create])
+ AC_CHECK_FUNCS([guestfs_dd])
+
+which would result in C<HAVE_GUESTFS_DD> being either defined
+or not defined in your program.
+
+=head2 SINGLE CALLS AT RUN TIME
+
+Testing at compile time doesn't guarantee that a function really
+exists in the library.  The reason is that you might be dynamically
+linked against a previous I<libguestfs.so> (dynamic library)
+which doesn't have the call.  This situation unfortunately results
+in a segmentation fault, which is a shortcoming of the C dynamic
+linking system itself.
+
+You can use L<dlopen(3)> to test if a function is available
+at run time, as in this example program (note that you still
+need the compile time check as well):
+
+ #include <config.h>
+ 
+ #include <stdio.h>
+ #include <stdlib.h>
+ #include <unistd.h>
+ #include <dlfcn.h>
+ #include <guestfs.h>
+ 
+ main ()
+ {
+ #ifdef HAVE_GUESTFS_DD
+   void *dl;
+   int has_function;
+ 
+   /* Test if the function guestfs_dd is really available. */
+   dl = dlopen (NULL, RTLD_LAZY);
+   if (!dl) {
+     fprintf (stderr, "dlopen: %s\n", dlerror ());
+     exit (1);
+   }
+   has_function = dlsym (dl, "guestfs_dd") != NULL;
+   dlclose (dl);
+ 
+   if (!has_function)
+     printf ("this libguestfs.so does NOT have guestfs_dd function\n");
+   else {
+     printf ("this libguestfs.so has guestfs_dd function\n");
+     /* Now it's safe to call
+     guestfs_dd (g, "foo", "bar");
+     */
+   }
+ #else
+   printf ("guestfs_dd function was not found at compile time\n");
+ #endif
+  }
+
+You may think the above is an awful lot of hassle, and it is.
+There are other ways outside of the C linking system to ensure
+that this kind of incompatibility never arises, such as using
+package versioning:
+
+ Requires: libguestfs >= 1.0.80
+
+=begin html
+
+<!-- old anchor for the next section -->
+<a name="state_machine_and_low_level_event_api"/>
+
+=end html
+
+=head1 ARCHITECTURE
+
+Internally, libguestfs is implemented by running an appliance (a
+special type of small virtual machine) using L<qemu(1)>.  Qemu runs as
+a child process of the main program.
+
+  ___________________
+ /                   \
+ | main program      |
+ |                   |
+ |                   |           child process / appliance
+ |                   |           __________________________
+ |                   |          / qemu                     \
+ +-------------------+   RPC    |      +-----------------+ |
+ | libguestfs     <--------------------> guestfsd        | |
+ |                   |          |      +-----------------+ |
+ \___________________/          |      | Linux kernel    | |
+                                |      +--^--------------+ |
+                                \_________|________________/
+                                          |
+                                   _______v______
+                                  /              \
+                                  | Device or    |
+                                  | disk image   |
+                                  \______________/
+
+The library, linked to the main program, creates the child process and
+hence the appliance in the L</guestfs_launch> function.
+
+Inside the appliance is a Linux kernel and a complete stack of
+userspace tools (such as LVM and ext2 programs) and a small
+controlling daemon called C<guestfsd>.  The library talks to
+C<guestfsd> using remote procedure calls (RPC).  There is a mostly
+one-to-one correspondence between libguestfs API calls and RPC calls
+to the daemon.  Lastly the disk image(s) are attached to the qemu
+process which translates device access by the appliance's Linux kernel
+into accesses to the image.
+
+A common misunderstanding is that the appliance "is" the virtual
+machine.  Although the disk image you are attached to might also be
+used by some virtual machine, libguestfs doesn't know or care about
+this.  (But you will care if both libguestfs's qemu process and your
+virtual machine are trying to update the disk image at the same time,
+since these usually results in massive disk corruption).
+
+=head1 STATE MACHINE
+
+libguestfs uses a state machine to model the child process:
+
+                         |
+                    guestfs_create
+                         |
+                         |
+                     ____V_____
+                    /          \
+                    |  CONFIG  |
+                    \__________/
+                     ^ ^   ^  \
+                    /  |    \  \ guestfs_launch
+                   /   |    _\__V______
+                  /    |   /           \
+                 /     |   | LAUNCHING |
+                /      |   \___________/
+               /       |       /
+              /        |  guestfs_launch
+             /         |     /
+    ______  /        __|____V
+   /      \ ------> /        \
+   | BUSY |         | READY  |
+   \______/ <------ \________/
+
+The normal transitions are (1) CONFIG (when the handle is created, but
+there is no child process), (2) LAUNCHING (when the child process is
+booting up), (3) alternating between READY and BUSY as commands are
+issued to, and carried out by, the child process.
+
+The guest may be killed by C<guestfs_kill_subprocess>, or may die
+asynchronously at any time (eg. due to some internal error), and that
+causes the state to transition back to CONFIG.
+
+Configuration commands for qemu such as C<guestfs_add_drive> can only
+be issued when in the CONFIG state.
+
+The high-level API offers two calls that go from CONFIG through
+LAUNCHING to READY.  C<guestfs_launch> blocks until the child process
+is READY to accept commands (or until some failure or timeout).
+C<guestfs_launch> internally moves the state from CONFIG to LAUNCHING
+while it is running.
+
+High-level API actions such as C<guestfs_mount> can only be issued
+when in the READY state.  These high-level API calls block waiting for
+the command to be carried out (ie. the state to transition to BUSY and
+then back to READY).  But using the low-level event API, you get
+non-blocking versions.  (But you can still only carry out one
+operation per handle at a time - that is a limitation of the
+communications protocol we use).
+
+Finally, the child process sends asynchronous messages back to the
+main program, such as kernel log messages.  Mostly these are ignored
+by the high-level API, but using the low-level event API you can
+register to receive these messages.
+
+=head2 SETTING CALLBACKS TO HANDLE EVENTS
+
+The child process generates events in some situations.  Current events
+include: receiving a log message, the child process exits.
+
+Use the C<guestfs_set_*_callback> functions to set a callback for
+different types of events.
+
+Only I<one callback of each type> can be registered for each handle.
+Calling C<guestfs_set_*_callback> again overwrites the previous
+callback of that type.  Cancel all callbacks of this type by calling
+this function with C<cb> set to C<NULL>.
+
+=head2 guestfs_set_log_message_callback
+
+ typedef void (*guestfs_log_message_cb) (guestfs_h *g, void *opaque,
+                                         char *buf, int len);
+ void guestfs_set_log_message_callback (guestfs_h *handle,
+                                        guestfs_log_message_cb cb,
+                                        void *opaque);
+
+The callback function C<cb> will be called whenever qemu or the guest
+writes anything to the console.
+
+Use this function to capture kernel messages and similar.
+
+Normally there is no log message handler, and log messages are just
+discarded.
+
+=head2 guestfs_set_subprocess_quit_callback
+
+ typedef void (*guestfs_subprocess_quit_cb) (guestfs_h *g, void *opaque);
+ void guestfs_set_subprocess_quit_callback (guestfs_h *handle,
+                                            guestfs_subprocess_quit_cb cb,
+                                            void *opaque);
+
+The callback function C<cb> will be called when the child process
+quits, either asynchronously or if killed by
+C<guestfs_kill_subprocess>.  (This corresponds to a transition from
+any state to the CONFIG state).
+
+=head2 guestfs_set_launch_done_callback
+
+ typedef void (*guestfs_launch_done_cb) (guestfs_h *g, void *opaque);
+ void guestfs_set_launch_done_callback (guestfs_h *handle,
+                                        guestfs_ready_cb cb,
+                                        void *opaque);
+
+The callback function C<cb> will be called when the child process
+becomes ready first time after it has been launched.  (This
+corresponds to a transition from LAUNCHING to the READY state).
+
+=head1 BLOCK DEVICE NAMING
+
+In the kernel there is now quite a profusion of schemata for naming
+block devices (in this context, by I<block device> I mean a physical
+or virtual hard drive).  The original Linux IDE driver used names
+starting with C</dev/hd*>.  SCSI devices have historically used a
+different naming scheme, C</dev/sd*>.  When the Linux kernel I<libata>
+driver became a popular replacement for the old IDE driver
+(particularly for SATA devices) those devices also used the
+C</dev/sd*> scheme.  Additionally we now have virtual machines with
+paravirtualized drivers.  This has created several different naming
+systems, such as C</dev/vd*> for virtio disks and C</dev/xvd*> for Xen
+PV disks.
+
+As discussed above, libguestfs uses a qemu appliance running an
+embedded Linux kernel to access block devices.  We can run a variety
+of appliances based on a variety of Linux kernels.
+
+This causes a problem for libguestfs because many API calls use device
+or partition names.  Working scripts and the recipe (example) scripts
+that we make available over the internet could fail if the naming
+scheme changes.
+
+Therefore libguestfs defines C</dev/sd*> as the I<standard naming
+scheme>.  Internally C</dev/sd*> names are translated, if necessary,
+to other names as required.  For example, under RHEL 5 which uses the
+C</dev/hd*> scheme, any device parameter C</dev/sda2> is translated to
+C</dev/hda2> transparently.
+
+Note that this I<only> applies to parameters.  The
+C<guestfs_list_devices>, C<guestfs_list_partitions> and similar calls
+return the true names of the devices and partitions as known to the
+appliance.
+
+=head2 ALGORITHM FOR BLOCK DEVICE NAME TRANSLATION
+
+Usually this translation is transparent.  However in some (very rare)
+cases you may need to know the exact algorithm.  Such cases include
+where you use C<guestfs_config> to add a mixture of virtio and IDE
+devices to the qemu-based appliance, so have a mixture of C</dev/sd*>
+and C</dev/vd*> devices.
+
+The algorithm is applied only to I<parameters> which are known to be
+either device or partition names.  Return values from functions such
+as C<guestfs_list_devices> are never changed.
+
+=over 4
+
+=item *
+
+Is the string a parameter which is a device or partition name?
+
+=item *
+
+Does the string begin with C</dev/sd>?
+
+=item *
+
+Does the named device exist?  If so, we use that device.
+However if I<not> then we continue with this algorithm.
+
+=item *
+
+Replace initial C</dev/sd> string with C</dev/hd>.
+
+For example, change C</dev/sda2> to C</dev/hda2>.
+
+If that named device exists, use it.  If not, continue.
+
+=item *
+
+Replace initial C</dev/sd> string with C</dev/vd>.
+
+If that named device exists, use it.  If not, return an error.
+
+=back
+
+=head2 PORTABILITY CONCERNS
+
+Although the standard naming scheme and automatic translation is
+useful for simple programs and guestfish scripts, for larger programs
+it is best not to rely on this mechanism.
+
+Where possible for maximum future portability programs using
+libguestfs should use these future-proof techniques:
+
+=over 4
+
+=item *
+
+Use C<guestfs_list_devices> or C<guestfs_list_partitions> to list
+actual device names, and then use those names directly.
+
+Since those device names exist by definition, they will never be
+translated.
+
+=item *
+
+Use higher level ways to identify filesystems, such as LVM names,
+UUIDs and filesystem labels.
+
+=back
+
+=head1 INTERNALS
+
+=head2 COMMUNICATION PROTOCOL
+
+Don't rely on using this protocol directly.  This section documents
+how it currently works, but it may change at any time.
+
+The protocol used to talk between the library and the daemon running
+inside the qemu virtual machine is a simple RPC mechanism built on top
+of XDR (RFC 1014, RFC 1832, RFC 4506).
+
+The detailed format of structures is in C<src/guestfs_protocol.x>
+(note: this file is automatically generated).
+
+There are two broad cases, ordinary functions that don't have any
+C<FileIn> and C<FileOut> parameters, which are handled with very
+simple request/reply messages.  Then there are functions that have any
+C<FileIn> or C<FileOut> parameters, which use the same request and
+reply messages, but they may also be followed by files sent using a
+chunked encoding.
+
+=head3 ORDINARY FUNCTIONS (NO FILEIN/FILEOUT PARAMS)
+
+For ordinary functions, the request message is:
+
+ total length (header + arguments,
+      but not including the length word itself)
+ struct guestfs_message_header (encoded as XDR)
+ struct guestfs_<foo>_args (encoded as XDR)
+
+The total length field allows the daemon to allocate a fixed size
+buffer into which it slurps the rest of the message.  As a result, the
+total length is limited to C<GUESTFS_MESSAGE_MAX> bytes (currently
+4MB), which means the effective size of any request is limited to
+somewhere under this size.
+
+Note also that many functions don't take any arguments, in which case
+the C<guestfs_I<foo>_args> is completely omitted.
+
+The header contains the procedure number (C<guestfs_proc>) which is
+how the receiver knows what type of args structure to expect, or none
+at all.
+
+The reply message for ordinary functions is:
+
+ total length (header + ret,
+      but not including the length word itself)
+ struct guestfs_message_header (encoded as XDR)
+ struct guestfs_<foo>_ret (encoded as XDR)
+
+As above the C<guestfs_I<foo>_ret> structure may be completely omitted
+for functions that return no formal return values.
+
+As above the total length of the reply is limited to
+C<GUESTFS_MESSAGE_MAX>.
+
+In the case of an error, a flag is set in the header, and the reply
+message is slightly changed:
+
+ total length (header + error,
+      but not including the length word itself)
+ struct guestfs_message_header (encoded as XDR)
+ struct guestfs_message_error (encoded as XDR)
+
+The C<guestfs_message_error> structure contains the error message as a
+string.
+
+=head3 FUNCTIONS THAT HAVE FILEIN PARAMETERS
+
+A C<FileIn> parameter indicates that we transfer a file I<into> the
+guest.  The normal request message is sent (see above).  However this
+is followed by a sequence of file chunks.
+
+ total length (header + arguments,
+      but not including the length word itself,
+      and not including the chunks)
+ struct guestfs_message_header (encoded as XDR)
+ struct guestfs_<foo>_args (encoded as XDR)
+ sequence of chunks for FileIn param #0
+ sequence of chunks for FileIn param #1 etc.
+
+The "sequence of chunks" is:
+
+ length of chunk (not including length word itself)
+ struct guestfs_chunk (encoded as XDR)
+ length of chunk
+ struct guestfs_chunk (encoded as XDR)
+   ...
+ length of chunk
+ struct guestfs_chunk (with data.data_len == 0)
+
+The final chunk has the C<data_len> field set to zero.  Additionally a
+flag is set in the final chunk to indicate either successful
+completion or early cancellation.
+
+At time of writing there are no functions that have more than one
+FileIn parameter.  However this is (theoretically) supported, by
+sending the sequence of chunks for each FileIn parameter one after
+another (from left to right).
+
+Both the library (sender) I<and> the daemon (receiver) may cancel the
+transfer.  The library does this by sending a chunk with a special
+flag set to indicate cancellation.  When the daemon sees this, it
+cancels the whole RPC, does I<not> send any reply, and goes back to
+reading the next request.
+
+The daemon may also cancel.  It does this by writing a special word
+C<GUESTFS_CANCEL_FLAG> to the socket.  The library listens for this
+during the transfer, and if it gets it, it will cancel the transfer
+(it sends a cancel chunk).  The special word is chosen so that even if
+cancellation happens right at the end of the transfer (after the
+library has finished writing and has started listening for the reply),
+the "spurious" cancel flag will not be confused with the reply
+message.
+
+This protocol allows the transfer of arbitrary sized files (no 32 bit
+limit), and also files where the size is not known in advance
+(eg. from pipes or sockets).  However the chunks are rather small
+(C<GUESTFS_MAX_CHUNK_SIZE>), so that neither the library nor the
+daemon need to keep much in memory.
+
+=head3 FUNCTIONS THAT HAVE FILEOUT PARAMETERS
+
+The protocol for FileOut parameters is exactly the same as for FileIn
+parameters, but with the roles of daemon and library reversed.
+
+ total length (header + ret,
+      but not including the length word itself,
+      and not including the chunks)
+ struct guestfs_message_header (encoded as XDR)
+ struct guestfs_<foo>_ret (encoded as XDR)
+ sequence of chunks for FileOut param #0
+ sequence of chunks for FileOut param #1 etc.
+
+=head3 INITIAL MESSAGE
+
+Because the underlying channel (QEmu -net channel) doesn't have any
+sort of connection control, when the daemon launches it sends an
+initial word (C<GUESTFS_LAUNCH_FLAG>) which indicates that the guest
+and daemon is alive.  This is what C<guestfs_launch> waits for.
+
+=head1 MULTIPLE HANDLES AND MULTIPLE THREADS
+
+All high-level libguestfs actions are synchronous.  If you want
+to use libguestfs asynchronously then you must create a thread.
+
+Only use the handle from a single thread.  Either use the handle
+exclusively from one thread, or provide your own mutex so that two
+threads cannot issue calls on the same handle at the same time.
+
+=head1 QEMU WRAPPERS
+
+If you want to compile your own qemu, run qemu from a non-standard
+location, or pass extra arguments to qemu, then you can write a
+shell-script wrapper around qemu.
+
+There is one important rule to remember: you I<must C<exec qemu>> as
+the last command in the shell script (so that qemu replaces the shell
+and becomes the direct child of the libguestfs-using program).  If you
+don't do this, then the qemu process won't be cleaned up correctly.
+
+Here is an example of a wrapper, where I have built my own copy of
+qemu from source:
+
+ #!/bin/sh -
+ qemudir=/home/rjones/d/qemu
+ exec $qemudir/x86_64-softmmu/qemu-system-x86_64 -L $qemudir/pc-bios "$@"
+
+Save this script as C</tmp/qemu.wrapper> (or wherever), C<chmod +x>,
+and then use it by setting the LIBGUESTFS_QEMU environment variable.
+For example:
+
+ LIBGUESTFS_QEMU=/tmp/qemu.wrapper guestfish
+
+Note that libguestfs also calls qemu with the -help and -version
+options in order to determine features.
+
+=head1 ENVIRONMENT VARIABLES
+
+=over 4
+
+=item LIBGUESTFS_APPEND
+
+Pass additional options to the guest kernel.
+
+=item LIBGUESTFS_DEBUG
+
+Set C<LIBGUESTFS_DEBUG=1> to enable verbose messages.  This
+has the same effect as calling C<guestfs_set_verbose (handle, 1)>.
+
+=item LIBGUESTFS_MEMSIZE
+
+Set the memory allocated to the qemu process, in megabytes.  For
+example:
+
+ LIBGUESTFS_MEMSIZE=700
+
+=item LIBGUESTFS_PATH
+
+Set the path that libguestfs uses to search for kernel and initrd.img.
+See the discussion of paths in section PATH above.
+
+=item LIBGUESTFS_QEMU
+
+Set the default qemu binary that libguestfs uses.  If not set, then
+the qemu which was found at compile time by the configure script is
+used.
+
+See also L</QEMU WRAPPERS> above.
+
+=item LIBGUESTFS_TRACE
+
+Set C<LIBGUESTFS_TRACE=1> to enable command traces.  This
+has the same effect as calling C<guestfs_set_trace (handle, 1)>.
+
+=item TMPDIR
+
+Location of temporary directory, defaults to C</tmp>.
+
+If libguestfs was compiled to use the supermin appliance then each
+handle will require rather a large amount of space in this directory
+for short periods of time (~ 80 MB).  You can use C<$TMPDIR> to
+configure another directory to use in case C</tmp> is not large
+enough.
+
+=back
+
+=head1 SEE ALSO
+
+L<guestfish(1)>,
+L<qemu(1)>,
+L<febootstrap(1)>,
+L<http://libguestfs.org/>.
+
+Tools with a similar purpose:
+L<fdisk(8)>,
+L<parted(8)>,
+L<kpartx(8)>,
+L<lvm(8)>,
+L<disktype(1)>.
+
+=head1 BUGS
+
+To get a list of bugs against libguestfs use this link:
+
+L<https://bugzilla.redhat.com/buglist.cgi?component=libguestfs&product=Virtualization+Tools>
+
+To report a new bug against libguestfs use this link:
+
+L<https://bugzilla.redhat.com/enter_bug.cgi?component=libguestfs&product=Virtualization+Tools>
+
+When reporting a bug, please check:
+
+=over 4
+
+=item *
+
+That the bug hasn't been reported already.
+
+=item *
+
+That you are testing a recent version.
+
+=item *
+
+Describe the bug accurately, and give a way to reproduce it.
+
+=item *
+
+Run libguestfs-test-tool and paste the B<complete, unedited>
+output into the bug report.
+
+=back
+
+=head1 AUTHORS
+
+Richard W.M. Jones (C<rjones at redhat dot com>)
+
+=head1 COPYRIGHT
+
+Copyright (C) 2009 Red Hat Inc.
+L<http://libguestfs.org/>
+
+This library is free software; you can redistribute it and/or
+modify it under the terms of the GNU Lesser General Public
+License as published by the Free Software Foundation; either
+version 2 of the License, or (at your option) any later version.
+
+This library 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
+Lesser General Public License for more details.
+
+You should have received a copy of the GNU Lesser General Public
+License along with this library; if not, write to the Free Software
+Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA