safeclib.c File Reference

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Description

Implementation of error-safe wrappers for some notorious C-Lib functions.

Definition in file safeclib.c.

#include "lib/error.h"
#include "lib/safeclib.h"
#include <string.h>
#include <stdlib.h>
#include <pthread.h>
#include <stdint.h>
#include <nobug.h>

Enumerations
enum	lumiera_resource {   LUMIERA_RESOURCE_MEMORY,   LUMIERA_RESOURCE_END }
	Resources known to the resource collector. More...
enum	lumiera_resource_try {   LUMIERA_RESOURCE_NONE,   LUMIERA_RESOURCE_ONE,   LUMIERA_RESOURCE_SOME,   LUMIERA_RESOURCE_MANY,   LUMIERA_RESOURCE_ALL,   LUMIERA_RESOURCE_PANIC,   LUMIERA_RESOURCE_UNREGISTER }
	Iteration indicator. More...

Functions
static int	die_no_mem (enum lumiera_resource which, enum lumiera_resource_try *iteration, void *context)
void *	lumiera_calloc (size_t n, size_t size)
	Allocate cleared memory for an array. More...
	LUMIERA_ERROR_DEFINE (NO_MEMORY, "Out of Memory!")
void *	lumiera_malloc (size_t size)
	Allocate memory. More...
void *	lumiera_realloc (void *ptr, size_t size)
	Change the size of a memory block. More...
int	lumiera_streq (const char *a, const char *b)
	check 2 strings for identity. More...
int	lumiera_strncmp (const char *a, const char *b, size_t len)
	Compare two C strings. More...
char *	lumiera_strndup (const char *str, size_t len)
	Duplicate a C string. More...

Enumeration Type Documentation

lumiera_resource

enum lumiera_resource

Resources known to the resource collector.

Todo:

10/2023 this is a left-over of the »resource-collector« plan

Enumerator
LUMIERA_RESOURCE_MEMORY	memory blocks, context is a pointer to the size_t required
LUMIERA_RESOURCE_END	OS filehandles. CPU time, as in threads and such mmaped regions disk space for the storage area, context is a pointer to the filename indication the device disk bandwidth for the storage area, context is a pointer to the filename indication the device disk space for the caching area, context is a pointer to the filename indication the device disk bandwidth for the caching area, context is a pointer to the filename indication the device

Definition at line 37 of file safeclib.c.

lumiera_resource_try

enum lumiera_resource_try

Iteration indicator.

Todo:

10/2023 this is a left-over of the »resource-collector« plan Resource collection works iteratively freeing more and more resources.

Handlers do not need to obey the request and shall return LUMIERA_RESOURCE_NONE which will then continue with the next handler. This goes through all available handlers until one returns a higher or same value than the current iteration to indicate that it freed enough resources to continue the task. Then control is passed back to the calling loop which retries the resource allocation. LUMIERA_RESOURCE_PANIC is somewhat special since it will always call all registered handlers for all resources, not only the queried one and finally _exit() the application. The exact amounts of resources to be freed for ONE, SOME and MANY in intentionally kept vague the handlers are free to interpret this in some sensible way.

Enumerator
LUMIERA_RESOURCE_NONE	No op, returned by a handler when it did nothing.
LUMIERA_RESOURCE_ONE	try to free one or really few of this resources
LUMIERA_RESOURCE_SOME	try to free a small reasonable implementation defined amount of resources
LUMIERA_RESOURCE_MANY	try to free a bigger implementation defined amount of resources
LUMIERA_RESOURCE_ALL	free as much as possible
LUMIERA_RESOURCE_PANIC	die!
LUMIERA_RESOURCE_UNREGISTER	When a handler gets unregistered it will be called with this value to give it a chance to clean up the user 'data'.

Definition at line 74 of file safeclib.c.

Function Documentation

die_no_mem()

static int die_no_mem ( enum lumiera_resource  which, enum lumiera_resource_try *  iteration, void *  context  )

static

placeholder function in case the resource-collector was not installed

Todo:

10/2023 in the early stages of the Lumiera project a centralised resource pooling was considered. On resource shortage, the (planned) resource-collector would attempt to reclaim excess resources. This would allow to use resources (e.g. memory) wastefully as trade-off for performance gains. This concept was never developed beyond an interface draft; most notably it was never clarified how excess resources could have been identified on-demand while in-flight. Today I view this concept as an immature plan and remove the remaining draft code.

Definition at line 104 of file safeclib.c.

References LUMIERA_DIE.

lumiera_malloc()

void* lumiera_malloc

(

size_t

sz

)

Allocate memory.

always succeeds or dies

Parameters

size	memory to be allocated

Returns

pointer to the allocated memory

Definition at line 113 of file safeclib.c.

References LUMIERA_RESOURCE_ONE.

Referenced by lumiera_plugin_new().

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lumiera_calloc()

void* lumiera_calloc	(	size_t	n,
		size_t	size
	)

Allocate cleared memory for an array.

always succeeds or dies

Parameters

n	number of elements
size	memory to be allocated

Returns

pointer to the allocated memory

Definition at line 130 of file safeclib.c.

References LUMIERA_RESOURCE_ONE.

lumiera_realloc()

void* lumiera_realloc	(	void *	ptr,
		size_t	size
	)

Change the size of a memory block.

Parameters

ptr	pointer to the old memory block obtained by lumiera_malloc or lumiera_calloc
size	new size of the block

Returns

address of new block

Definition at line 149 of file safeclib.c.

References LUMIERA_RESOURCE_ONE.

lumiera_strndup()

char* lumiera_strndup	(	const char *	str,
		size_t	len
	)

Duplicate a C string.

always succeeds or dies

Parameters

str	string to be copied
len	maximal length to be copied

Returns

pointer to the new string, "" if NULL was passed as str

Definition at line 166 of file safeclib.c.

References LUMIERA_RESOURCE_ONE.

Referenced by lumiera_free(), and lumiera_plugin_new().

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lumiera_strncmp()

int lumiera_strncmp	(	const char *	a,
		const char *	b,
		size_t	len
	)

Compare two C strings.

Handles NULL pointers as "", shortcut for same addresses

Parameters

a	first string for comparsion
b	second string for comparsion
len	maximal length for the comparsion

Returns

0 if the strings are identical, -1 if smaller 1 if bigger.

Definition at line 184 of file safeclib.c.

Referenced by lumiera_free(), and lumiera_streq().

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lumiera_streq()

int lumiera_streq	(	const char *	a,
		const char *	b
	)

check 2 strings for identity.

Parameters

a	first string for comparsion
b	second string for comparsion

Returns

1 when the strings are the the same, 0 if not.

Definition at line 191 of file safeclib.c.

References lumiera_strncmp().

Referenced by lumiera_free().

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