cupsfrontend.c File Reference

Functions to act as a CUPS filter. More...

Functions
static void	handle_sigterm (int signal)
static int	prepare_signals (void)
static int	cups_ql_input_raster_file_open (struct qldriver *ql)
static int	cups_ql_ppd_file_open (struct qldriver *ql, int option_cnt, cups_option_t options[option_cnt])
int	main (int argc, const char *argv[])

Variables
int	terminate
static struct sigaction	signal_pipe [2]
static struct sigaction	signal_term [2]

Detailed Description

Functions to act as a CUPS filter.

Copyright

GNU General Public License 2.0 or later

Author

Jürgen Borleis

Function Documentation

cups_ql_input_raster_file_open()

static int cups_ql_input_raster_file_open ( struct qldriver *  ql )

static

'Take a look' into the CUPS raster file

Parameters

[in,out]

ql

Full job description

Return values

0	On succes
-EINVAL	Failed to open the raster input file

cups_ql_ppd_file_open()

static int cups_ql_ppd_file_open ( struct qldriver *  ql, int  option_cnt, cups_option_t  options[option_cnt]  )

static

Get access to the printer's PPD file and its settings for this job

Parameters

[in]	ql	Full job description
[in]	option_cnt	Count of elements in options
[in]	options	Optional parameters

Return values

-EINVAL	Missing PPD environment variable
-ENODATA	Bad PPD content
0	On success

handle_sigterm()

static void handle_sigterm ( int  signal )

static

main()

int main	(	int	argc,
		const char *	argv[]
	)

Main entry function.

Parameters

argc	number of command line arguments plus one
argv	command line arguments

Returns

0 if success, nonzero otherwise

https://opensource.apple.com/source/cups/cups-327/cups/doc/help/api-filter.html

We get:

• argv[1] The job ID
• argv[2] The user printing the job
• argv[3] The job name/title
• argv[4] The number of copies to print (only valid if argv[6] is given!)
• argv[5] The options that were provided when the job was submitted
• argv[6] The file to print (optional)

prepare_signals()

static int prepare_signals ( void  )

static

Prepare for signal handling

Return values

0	On success
Negative	on failure

Signals handled are:

• SIGTERM: when a printing job is canceled or held
• SIGPIPE: when an upstream or downstream filter/backend exits with a non-zero status

Note: SIGPIPE should be ignored in any case in this environment.

Variable Documentation

signal_pipe

struct sigaction signal_pipe[2]

static

Initial value:

= {
    {
        .sa_handler = SIG_IGN,  
        .sa_flags = 0,
    },
}

signal_term

struct sigaction signal_term[2]

static

Initial value:

= {
    {
        .sa_handler = handle_sigterm,
        .sa_flags = 0,
    },
}

terminate

int terminate

Change to '1' to signal the program should stop