Some helper functions common for various libraries and programs. More...

Macros
#define	COPY_BUFFER_SIZE 4096

Functions
static int	caps_helper_string_validate (const char *string, size_t max_len)

static int	caps_helper_file_name_validate (const char *file_name)

static char *	_caps_helper_create_full_path (const char default_path, const char environment_var, const char *file_name)

static int	_caps_helper_return_directory_fd (const char default_path, const char environment_var)

char *	caps_helper_driver_db_path_create (const char *file_name)

int	caps_helper_driver_db_dir_fd (void)

char *	caps_helper_driver_config_path_create (const char *file_name)

int	caps_helper_driver_config_dir_fd (void)

char *	caps_helper_driver_path_create (const char *file_name)

int	caps_helper_driver_dir_fd (void)

char *	caps_helper_device_db_path_create (const char *file_name)

int	caps_helper_device_db_dir_fd (void)

char *	caps_helper_config_path_create (const char *file_name)

int	caps_helper_config_dir_fd (void)

int	caps_helper_number_convert (const char *string)

int	caps_helper_boolean_check (const char *value, int set)

static void	create_invisible_temp_file_standard (int *file)

int	caps_helper_invisible_file_create (int *file)

int	caps_helper_file_content_copy (int fd_to, int fd_from)

int	caps_helper_verbosity_setup (const char *keyword, bool overwrite)

Detailed Description

Copyright: GNU Lesser General Public License 2.1 or later

Author: Jürgen Borleis

Warning: Use as experimental

Note: The global API you can find here: libcapsbase: API description

Macro Definition Documentation

◆ COPY_BUFFER_SIZE

#define COPY_BUFFER_SIZE 4096

Byte count copied at once, refer caps_helper_file_content_copy

Function Documentation

◆ caps_helper_string_validate()

static int caps_helper_string_validate	(	const char *	string,
		size_t	max_len
	)

static

Ensure a string is a valid C-String (duck test)

Parameters

[in]	string	String to check
[in]	max_len	Accepted max length of this string

Returns: 0 if the string is valid (e.g. has a terminating '\0' in the given range)

Note: Only done in debug mode

Attention: If no '\0' is found within the range of max_len, this function might touch invalid memory!

◆ caps_helper_file_name_validate()

static int caps_helper_file_name_validate ( const char * file_name )

static

Be paranoid and check for a sane filename (no path)

Parameters

[in] file_name The file name to check

Returns: 0 if file_name contains a valid file name

Note: Only done in debug mode

Todo:

Could be a global function for other modules to validate filenames at their "border"

The max length of a filename depends on the underlying filesystem

◆ _caps_helper_create_full_path()

static char * _caps_helper_create_full_path	(	const char *	default_path,
		const char *	environment_var,
		const char *	file_name
	)

static

Create a full qualified path to a directory or a file

Parameters

[in]	default_path	The compiled-in directory path
[in]	environment_var	The environment variable to provide the directory path (in case of debugging is enabled)
[in]	file_name	The file name in the directory (can be NULL)

Returns: Pointer to a full qualified path to a directory or a file

Precondition: file_name must be NULL or a valid single name (no path!)

In the case file_name is NULL, it returns default_path or (if debugging is enabled) the content of the environment variable named in environment_var in a newly allocated buffer. If file_name isn't NULL, the returned buffer additionally contains the file name as its trailing component.

Note: If debugging is enabled the environment variable (if set) has always precedence over the default_path.

Postcondition: The allocated buffer must be freed after use.

◆ _caps_helper_return_directory_fd()

static int _caps_helper_return_directory_fd	(	const char *	default_path,
		const char *	environment_var
	)

static

Return a file descriptor for a directory

Parameters

[in]	default_path	The compiled-in directory path
[in]	environment_var	The environment variable to provide the directory path (in case of debugging is enabled)

Returns: The directory's file descriptor or negative errno in case of failure

The file descriptor is intended for use with the various *at() functions (openat() for example).

Returns always the file descriptor of directory default_path or (if debugging is enabled) of the directory defined by the environment variable named in environment_var (if defined at run-time).

Note: If debugging is enabled the environment variable (if set) has always precedence over the default_path.; The file descriptor must be closed after use.

Todo:: The file descriptor is opened for read only, which might be not helpful.

◆ create_invisible_temp_file_standard()

static void create_invisible_temp_file_standard ( int * file )

static

Create an invisible and self-removing temp. file in a standard way

Parameters

[out] file Where to store the filedescriptor

Note: This way should work on every platform (unlink a still open file).

This is the standard way to create a (mostly) invisible and self-removing file when there are other ways missing. If someone monitors the directory it is still possible to catch the file.

Todo:: If the unlink (e.g. hiding) fails: should it be an error?

Macros

Functions

Detailed Description

Macro Definition Documentation

◆ COPY_BUFFER_SIZE

Function Documentation

◆ caps_helper_string_validate()

◆ caps_helper_file_name_validate()

◆ _caps_helper_create_full_path()

◆ _caps_helper_return_directory_fd()

◆ create_invisible_temp_file_standard()