lib-caps-printer-prep.c File Reference

A collection of functions used by caps-printer-prep. More...

Functions
void	caps_prn_print_verbose_printer_message (const struct usb_printer *prn)
static int	caps_prn_fix_directory_permissions (const char *dir)
static int	caps_prn_create_initial_parameter_ini (const struct usb_printer *usb_prn, const char *dir)
static bool	whitespace_less (const char *string)
static const char *	caps_prn_get_useful_default_name (const struct usb_printer *prn)
static int	caps_prn_create_unique_parameter_dir (const struct usb_printer *prn, char **param_dir)
int	caps_prn_recognize_new_printer_device (const struct usb_printer *prn, struct caps_inif_table *db)

Detailed Description

Copyright

GNU Lesser General Public License 2.1

Author

Jürgen Borleis

Warning

Use as experimental

This collection isn't part of the main C file in order to run tests on it.

Function Documentation

caps_prn_print_verbose_printer_message()

void caps_prn_print_verbose_printer_message

(

const struct usb_printer *

prn

)

Fill the log with some useful information about the found printer device.

Parameters

[in]

prn

The USB printer device information

Give the user a chance to find/install the correct printer driver for this device by providing more useful information about it.

Todo:

Use the libusb DEVICE ID database ("/usr/share/misc/usb.ids") to output better Vendor and Device information.

Check what the tool 'usb_printerid' is

Avoid duplicate code, refer caps_prn_print_verbose_printer_message() in caps-printer.c

caps_prn_fix_directory_permissions()

static int caps_prn_fix_directory_permissions ( const char *  dir )

static

Adapt the permissions and owners of the given directory to our needs

Parameters

[in]

dir

Path to a directory (not(!) a file) to adapt

Return values

0	On success
negative	-errno else

All regular CAPS components should have only read access to all kind of resources in the filesystem Expected here is, we are running as root to be able to change the owner/group of the directory.

caps_prn_create_initial_parameter_ini()

static int caps_prn_create_initial_parameter_ini ( const struct usb_printer *  usb_prn, const char *  dir  )

static

Create an INI file to define a default name for the new printer device

Parameters

[in]	usb_prn	Printer device description from the USB point of view
[in]	dir	Directory name of the driver's run-time parameter directory

Return values

0	On success
negative	-errno else

usb_prn is used to create a useful default name for this new printer device

Note

We need to be root here to be able to change the file's owner

whitespace_less()

static bool whitespace_less ( const char *  string )

static

Check if a string does not contain whitespace

Parameters

[in]

string

String to check for whitespaces

Return values

true	If the string is whitespace less
false	If the string contains whitespaces

Todo:

Find an optimized way from the str* family of functions

caps_prn_get_useful_default_name()

static const char * caps_prn_get_useful_default_name ( const struct usb_printer *  prn )

static

Return something useful to create a directory name for a printer from it

Parameters

[in]

prn

Printer Device info

Returns

Pointer to some (hopefully) useful string

What is a useful name? Hard to say. The product name is to be preferred, because it is the best for the reader. The manufacturer name is also okay, but might be confusing, if more than one printer device of the same manufacturer is/was connected. The IEEE ID is more useful for technicians and the serial number is a pain - but can be some kind of last resourt. And if nothing of this information is available, just the name "printer" helps.

Todo:

None of the returned strings should embed a whitespace!

caps_prn_create_unique_parameter_dir()

static int caps_prn_create_unique_parameter_dir ( const struct usb_printer *  prn, char **  param_dir  )

static

Create a printer device unique CAPS Printer Device Parameter Directory in the main CAPS Printer Device Database Directory and return the full path to it

Parameters

[in]	prn	Printer Device Info
[out]	param_dir	Full path to the "CAPS Printer Device Parameter Directory" for this printer

Return values

0	On success (*param_dir is valid)
negative	Errno code about whats failed (mkdtemp(), chown() and chmod() calls)

This function will create a directory like: /var/lib/caps/printer_768747 with owner #CAPS_ADMIN_ID and group #CAPS_GROUP_ID and 0755 permission.

Note

*param_dir needs to be freed after use.

Function doesn't return on memory pressure

caps_prn_recognize_new_printer_device()

int caps_prn_recognize_new_printer_device	(	const struct usb_printer *	prn,
		struct caps_inif_table *	db
	)

The printer device isn't known yet. Search the printer driver database for a corresponding printer driver.

Parameters

[in]	prn	The USB printer device information
[in,out]	db	The current device database to store the new entry to (on demand)

Return values

0	On success
negative	Ernno

If a printer driver is found, create its corresponding Instance's Parameter Directory in the Driver's Configuration Directory, create the file service.ini with the parameter entry 'name' and a unique name (to be adpated by the user) and add this information beside some other run-time information (like the USB connection to recognize this printer device the next time) to its run-time database.

Note

The run-time information is only added to the in-memory device database. And still needs to be written back to the filesystem

Think about: We could create everything relevant even for the case no printer driver is installed. We just skip the parameter directory and description INI in this case and stop here. But the run-time database gets updated so we know the printer the next time and amend the missing information when available.