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.Dd July 5, 2011
.Dt TCPLAY 3
.Os
.Sh NAME
.Nm tc_api_init ,
.Nm tc_api_uninit ,
.Nm tc_api_create_volume ,
.Nm tc_api_map_volume ,
.Nm tc_api_unmap_volume ,
.Nm tc_api_check_cipher ,
.Nm tc_api_check_prf_hash ,
.Nm tc_api_get_error_msg ,
.Nm tc_api_get_summary
.Nd TrueCrypt volume management
.Sh LIBRARY
.Lb libtcplay
.Sh SYNOPSIS
.In sys/types.h
.In tcplay_api.h
.Ft int
.Fn tc_api_init "int verbose"
.Ft int
.Fn tc_api_uninit "void"
.Ft int
.Fn tc_api_create_volume "tc_api_opts *api_opts"
.Ft int
.Fn tc_api_map_volume "tc_api_opts *api_opts"
.Ft int
.Fn tc_api_unmap_volume "tc_api_opts *api_opts"
.Ft int
.Fn tc_api_check_cipher "tc_api_opts *api_opts"
.Ft int
.Fn tc_api_check_prf_hash "tc_api_opts *api_opts"
.Ft const char *
.Fn tc_api_get_error_msg "void"
.Ft const char *
.Fn tc_api_get_summary "void"
.Sh DESCRIPTION
The
.Nm tcplay
library provides an interface to create, query and map
TrueCrypt-compatible
volumes.
.Pp
The
.Fn tc_api_create_volume ,
.Fn tc_api_map_volume ,
.Fn tc_api_unmap_volume ,
.Fn tc_api_check_cipher
and
.Fn tc_api_check_prf_hash
functions take a
.Vt tc_api_opts
data structure as only argument, which is defined as follows:
.Bd -literal
typedef struct tc_api_opts {
	/* Common fields */
	char		*tc_device;
	char		*tc_passphrase;
	const char	**tc_keyfiles;

	/* Fields for mapping */
	char		*tc_map_name;
	int		tc_password_retries;
	int		tc_interactive_prompt;
	unsigned long	tc_prompt_timeout;

	/* Fields for creation */
	char		*tc_cipher;
	char		*tc_prf_hash;
	char		*tc_cipher_hidden;
	char		*tc_prf_hash_hidden;
	size_t		tc_size_hidden_in_bytes;
	char		*tc_passphrase_hidden;
	const char	**tc_keyfiles_hidden;
} tc_api_opts;
.Ed
.Pp
where the keyfile fields,
.Fa tc_keyfiles
and
.Fa tc_keyfiles_hidden ,
are
.Dv NULL
terminated arrays of key file strings.
.Pp
The
.Fn tc_api_init
function initializes the library internals and prepares it for use via
the API.
This function has to be called before using any other API function.
If the
.Fa verbose
argument is non-zero, then the library will output information such as
errors via stdout and stderr.
.Pp
The
.Fn tc_api_uninit
function clears up all internal secure memory, such as memory used for
decrypted headers, passphrases, keyfiles, etc.
.Pp
The
.Fn tc_api_create_volume
function creates a new volume using the parameters specified in the
.Fa api_opts
argument.
The new volume will be created on the device specified by
.Fa tc_device
using the cipher specified by
.Fa tc_cipher
and the pbkdf2 prf hash algorithm specified by
.Fa tc_prf_hash
and using the passphrase and keyfiles specified by
.Fa tc_passphrase
and
.Fa tc_keyfiles
respectively.
If
.Fa tc_size_hidden_in_bytes
is not zero, a hidden volume of the given size will be created, using
the cipher specified by
.Fa tc_cipher_hidden
and the pbkdf2 prf hash algorithm specified by
.Fa tc_prf_hash_hidden .
If
.Fa tc_cipher_hidden
or
.Fa tc_prf_hash_hidden
are
.Dv NULL ,
the same algorithm as for the outer volume will be used.
The passphrase and keyfiles used are specified by
.Fa tc_passphrase_hidden
and
.Fa tc_keyfiles_hidden
respectively.
.Pp
The
.Fn tc_api_map_volume
function maps a volume using the parameters specified in the
.Fa api_opts
argument.
The volume, which will be mapped as
.Fa tc_map_name ,
is specified in
.Fa tc_device .
The
.Fa tc_interactive_prompt
field determines whether the user will be prompted to enter a passphrase
interactively or whether the passphrase in
.Fa tc_passphrase
will be used.
If an interactive prompt is used, the prompt will time out after
.Fa tc_prompt_timeout
seconds.
A value of 0 indicates that no timeout will occur.
The number of passphrase entry retries is defined by
.Fa tc_password_retries .
Note that the
.Fn tc_api_map_volume
function does not support accessing an outer volume while
protecting the hidden volume.
Depending on the passphrase/keyfiles used
either the outer or the hidden volume will be mapped.
.Pp
The
.Fn tc_api_unmap_volume
unmaps / closes the volume specified in
.Fa tc_map_name .
.Pp
The
.Fn tc_api_check_cipher
function checks whether the cipher specified in the
.Fa api_opts
argument field
.Fa tc_cipher
is valid.
.Pp
The
.Fn tc_api_check_prf_hash
function checks whether the prf hash algorithm specified in the
.Fa api_opts
argument field
.Fa tc_prf_hash
is valid.
.Pp
The
.Fn tc_api_get_error_msg
function should be called whenver another API function returns
.Dv TC_ERR .
It returns a string containing a description of the error that
occurred.
.Pp
The
.Fn tc_api_get_summary
function returns a string containing a summary of the current
progress of a certain operation.
Currently only the volume erasing
part of creating a new volume can provide a summary.
When no summary is available, an empty string is returned.
The output otherwise is equivalent to that of a
.Dv SIGINFO
signal when using
.Xr tcplay 8 .
.Sh RETURN VALUES
All functions except
.Fn tc_api_get_error_msg
and
.Fn tc_api_get_summary
return either
.Dv TC_OK
to signal that the operation completed successfully, or
.Dv TC_ERR
to signal that an error occurred.
.Pp
The
.Fn tc_api_get_error_msg
and
.Fn tc_api_get_summary
always return a valid, but possibly empty, string.
.Sh COMPATIBILITY
The
.Nm tcplay
library offers full compatibility with TrueCrypt volumes including
hidden
volumes, system encryption (map-only), keyfiles and cipher cascading.
.Sh SEE ALSO
.Xr tcplay 8
.Sh HISTORY
The
.Nm tcplay
library appeared in
.Dx 2.11 .
.Sh AUTHORS
.An Alex Hornung