=head2 INSPECTION
Libguestfs has APIs for inspecting an unknown disk image to find out
-if it contains operating systems. (These APIs used to be in a
-separate Perl-only library called L<Sys::Guestfs::Lib(3)> but since
-version 1.5.3 the most frequently used part of this library has been
-rewritten in C and moved into the core code).
+if it contains operating systems, an install CD or a live CD. (These
+APIs used to be in a separate Perl-only library called
+L<Sys::Guestfs::Lib(3)> but since version 1.5.3 the most frequently
+used part of this library has been rewritten in C and moved into the
+core code).
Add all disks belonging to the unknown virtual machine and call
L</guestfs_launch> in the usual way.
differently from the other calls and does read the disks. See
documentation for that function for details).
+=head3 INSPECTING INSTALL DISKS
+
+Libguestfs (since 1.9.4) can detect some install disks, install
+CDs, live CDs and more.
+
+Call L</guestfs_inspect_get_format> to return the format of the
+operating system, which currently can be C<installed> (a regular
+operating system) or C<installer> (some sort of install disk).
+
+Further information is available about the operating system that can
+be installed using the regular inspection APIs like
+L</guestfs_inspect_get_product_name>,
+L</guestfs_inspect_get_major_version> etc.
+
+Some additional information specific to installer disks is also
+available from the L</guestfs_inspect_is_live>,
+L</guestfs_inspect_is_netinst> and L</guestfs_inspect_is_multipart>
+calls.
+
=head2 SPECIAL CONSIDERATIONS FOR WINDOWS GUESTS
Libguestfs can mount NTFS partitions. It does this using the
=item B<Perl>
-See L<Sys::Guestfs(3)>.
+See L<guestfs-perl(3)> and L<Sys::Guestfs(3)>.
=item B<PHP>
Note that libguestfs also calls qemu with the -help and -version
options in order to determine features.
+=head2 ATTACHING TO RUNNING DAEMONS
+
+I<Note (1):> This is B<highly experimental> and has a tendency to eat
+babies. Use with caution.
+
+I<Note (2):> This section explains how to attach to a running daemon
+from a low level perspective. For most users, simply using virt tools
+such as L<guestfish(1)> with the I<--live> option will "just work".
+
+=head3 Using guestfs_set_attach_method
+
+By calling L</guestfs_set_attach_method> you can change how the
+library connects to the C<guestfsd> daemon in L</guestfs_launch>
+(read L</ARCHITECTURE> for some background).
+
+The normal attach method is C<appliance>, where a small appliance is
+created containing the daemon, and then the library connects to this.
+
+Setting attach method to C<unix:I<path>> (where I<path> is the path of
+a Unix domain socket) causes L</guestfs_launch> to connect to an
+existing daemon over the Unix domain socket.
+
+The normal use for this is to connect to a running virtual machine
+that contains a C<guestfsd> daemon, and send commands so you can read
+and write files inside the live virtual machine.
+
+=head3 Using guestfs_add_domain with live flag
+
+L</guestfs_add_domain> provides some help for getting the
+correct attach method. If you pass the C<live> option to this
+function, then (if the virtual machine is running) it will
+examine the libvirt XML looking for a virtio-serial channel
+to connect to:
+
+ <domain>
+ ...
+ <devices>
+ ...
+ <channel type='unix'>
+ <source mode='bind' path='/path/to/socket'/>
+ <target type='virtio' name='org.libguestfs.channel.0'/>
+ </channel>
+ ...
+ </devices>
+ </domain>
+
+L</guestfs_add_domain> extracts C</path/to/socket> and sets the attach
+method to C<unix:/path/to/socket>.
+
+Some of the libguestfs tools (including guestfish) support a I<--live>
+option which is passed through to L</guestfs_add_domain> thus allowing
+you to attach to and modify live virtual machines.
+
+The virtual machine needs to have been set up beforehand so that it
+has the virtio-serial channel and so that guestfsd is running inside
+it.
+
=head2 ABI GUARANTEE
We guarantee the libguestfs ABI (binary interface), for public,
=head1 PRIVATE DATA AREA
You can attach named pieces of private data to the libguestfs handle,
-and fetch them by name for the lifetime of the handle. This is called
-the private data area and is only available from the C API.
+fetch them by name, and walk over them, for the lifetime of the
+handle. This is called the private data area and is only available
+from the C API.
To attach a named piece of data, use the following call:
set up a close callback to do it (see L</guestfs_set_close_callback>,
and note that only one callback can be registered for a handle).
-The private data area is implemented using a hash table, and should be
-reasonably efficient for moderate numbers of keys.
+To walk over all entries, use these two functions:
+
+ void *guestfs_first_private (guestfs_h *g, const char **key_rtn);
+
+ void *guestfs_next_private (guestfs_h *g, const char **key_rtn);
+
+C<guestfs_first_private> returns the first key, pointer pair ("first"
+does not have any particular meaning -- keys are not returned in any
+defined order). A pointer to the key is returned in C<*key_rtn> and
+the corresponding data pointer is returned from the function. C<NULL>
+is returned if there are no keys stored in the handle.
+
+C<guestfs_next_private> returns the next key, pointer pair. The
+return value of this function is also C<NULL> is there are no further
+entries to return.
+
+Notes about walking over entries:
+
+=over 4
+
+=item *
+
+You must not call C<guestfs_set_private> while walking over the
+entries.
+
+=item *
+
+The handle maintains an internal iterator which is reset when you call
+C<guestfs_first_private>. This internal iterator is invalidated when
+you call C<guestfs_set_private>.
+
+=item *
+
+If you have set the data pointer associated with a key to C<NULL>, ie:
+
+ guestfs_set_private (g, key, NULL);
+
+then that C<key> is not returned when walking.
+
+=item *
+
+C<*key_rtn> is only valid until the next call to
+C<guestfs_first_private>, C<guestfs_next_private> or
+C<guestfs_set_private>.
+
+=back
+
+The following example code shows how to print all keys and data
+pointers that are associated with the handle C<g>:
+
+ const char *key;
+ void *data = guestfs_first_private (g, &key);
+ while (data != NULL)
+ {
+ printf ("key = %s, data = %p\n", key, data);
+ data = guestfs_next_private (g, &key);
+ }
+
+More commonly you are only interested in keys that begin with an
+application-specific prefix C<foo_>. Modify the loop like so:
+
+ const char *key;
+ void *data = guestfs_first_private (g, &key);
+ while (data != NULL)
+ {
+ if (strncmp (key, "foo_", strlen ("foo_")) == 0)
+ printf ("key = %s, data = %p\n", key, data);
+ data = guestfs_next_private (g, &key);
+ }
+
+If you need to modify keys while walking, then you have to jump back
+to the beginning of the loop. For example, to delete all keys
+prefixed with C<foo_>:
+
+ const char *key;
+ void *data;
+ again:
+ data = guestfs_first_private (g, &key);
+ while (data != NULL)
+ {
+ if (strncmp (key, "foo_", strlen ("foo_")) == 0)
+ {
+ guestfs_set_private (g, key, NULL);
+ /* note that 'key' pointer is now invalid, and so is
+ the internal iterator */
+ goto again;
+ }
+ data = guestfs_next_private (g, &key);
+ }
+
+Note that the above loop is guaranteed to terminate because the keys
+are being deleted, but other manipulations of keys within the loop
+might not terminate unless you also maintain an indication of which
+keys have been visited.
=begin html
L<virt-inspector(1)>, the virtual machine image inspector.
+=item C<logo>
+
+Logo used on the website. The fish is called Arthur by the way.
+
=item C<m4>
M4 macros used by autoconf.
=item TMPDIR
-Location of temporary directory, defaults to C</tmp>.
+Location of temporary directory, defaults to C</tmp> except for the
+cached supermin appliance which defaults to C</var/tmp>.
If libguestfs was compiled to use the supermin appliance then the
real appliance is cached in this directory, shared between all
handles belonging to the same EUID. You can use C<$TMPDIR> to
-configure another directory to use in case C</tmp> is not large
+configure another directory to use in case C</var/tmp> is not large
enough.
=back
git.annexia.org / libguestfs.git / blobdiff