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 other languages, if people
-contribute the language bindings). You can also use it from shell
-scripts or the command line.
+programs (or management programs written in OCaml, Perl or Python).
+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.
Create a connection handle.
You have to call C<guestfs_add_drive> on the handle at least once.
-See CONFIGURATION MANAGEMENT section below.
This function returns a non-NULL pointer to a handle on success or
NULL on error.
This closes the connection handle and frees up all resources used.
-=head2 guestfs_launch, guestfs_wait_ready
-
- int guestfs_launch (guestfs_h *handle);
- int guestfs_wait_ready (guestfs_h *handle);
-
-Internally libguestfs is implemented by running a virtual machine
-using L<qemu(1)>. These calls are necessary in order to boot the
-virtual machine. More discussion of this is available in the section
-STATE MACHINE AND LOW-LEVEL EVENT API below.
-
-You should call these two functions after configuring the handle
-(eg. adding drives) but before performing any actions.
-
-=head2 guestfs_kill_subprocess
-
- int guestfs_kill_subprocess (guestfs_h *handle);
-
-This kills the qemu subprocess. You should never need to call this.
-
-=head1 CONFIGURATION MANAGEMENT
-
-The configuration functions allow you to configure which drive images
-will be examined or modified, and set other aspects of the L<qemu(1)>
-virtual machine that we will be running. You need to call only
-C<guestfs_add_drive> at least once for each guest image that you want
-to examine.
-
-=head2 guestfs_add_drive
-
- int guestfs_add_drive (guestfs_h *handle, const char *filename);
-
-This function adds a virtual machine disk image C<filename> to the
-guest. The first time you call this function, the disk appears as IDE
-disk 0 (C</dev/sda>) in the guest, the second time as C</dev/sdb>, and
-so on.
-
-You don't necessarily need to be root when using libguestfs. However
-you obviously do need sufficient permissions to access the filename
-for whatever operations you want to perform (ie. read access if you
-just want to read the image or write access if you want to modify the
-image).
-
-This is equivalent to the qemu parameter C<-drive file=filename>.
-
-=head2 guestfs_add_cdrom
-
- int guestfs_add_cdrom (guestfs_h *handle, const char *filename);
-
-This function adds a virtual CD-ROM disk image to the guest.
-
-This is equivalent to the qemu parameter C<-cdrom filename>.
-
-=head2 guestfs_config
-
- int guestfs_config (guestfs_h *handle,
- const char *qemu_param, const char *qemu_value);
-
-This can be used to add arbitrary qemu command line parameters
-of the form C<-param value>. Actually it's not quite arbitrary - we
-prevent you from setting some parameters which would interfere with
-parameters that we use.
-
-The first character of C<qemu_param> string must be a C<-> (dash).
-
-C<qemu_value> can be NULL.
-
=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_set_error_handler>. The default error
-handler prints the information string to C<stderr>.
+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,
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 and the error
-message is completely discarded.
+If you set C<cb> to C<NULL> then I<no> handler is called.
=head2 guestfs_get_error_handler
This returns the current out of memory handler.
-=head1 VERBOSE MESSAGES
-
-=head2 guestfs_set_verbose
-
- void guestfs_set_verbose (guestfs_h *handle, int verbose);
+=head1 PATH
-If C<verbose> is true, this turns on verbose messages (to C<stderr>).
+Libguestfs needs a kernel and initrd.img, which it finds by looking
+along an internal path.
-Verbose messages are disabled unless the environment variable
-C<LIBGUESTFS_DEBUG> is defined and set to C<1>.
+By default it looks for these in the directory C<$libdir/guestfs>
+(eg. C</usr/local/lib/guestfs> or C</usr/lib64/guestfs>).
-=head2 guestfs_get_verbose
-
- int guestfs_get_verbose (guestfs_h *handle);
-
-This returns the verbose messages flag.
+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
@ACTIONS@
+=head1 STRUCTURES
+
+@STRUCTS@
+
=head1 STATE MACHINE AND LOW-LEVEL EVENT API
Internally, libguestfs is implemented by running a virtual machine
This isn't documented. Please see the libguestfs-select and
libguestfs-glib implementations.
-=head1 SEE ALSO
+=head1 ENVIRONMENT VARIABLES
-L<qemu(1)>
+=over 4
+=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_PATH
+
+Set the path that libguestfs uses to search for kernel and initrd.img.
+See the discussion of paths in section PATH above.
+
+=back
+
+=head1 SEE ALSO
+L<guestfish(1)>,
+L<qemu(1)>,
+L<febootstrap(1)>,
+L<http://et.redhat.com/~rjones/libguestfs>.
=head1 AUTHORS
git.annexia.org / libguestfs.git / blobdiff