cbuf.c File Reference

#include <sys/types.h>
#include <sys/stat.h>
#include <sys/mman.h>
#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include "class.h"
#include "utils/memory.h"
#include "cbuf.h"

Include dependency graph for cbuf.c:

Go to the source code of this file.

Macros
#define	_POSIX_SOURCE
#define	_POSIX_C_SOURCE   200112L
#define	_GNU_SOURCE

Functions
static void	cbufDtor (void *)
static int	cbufCtor (void *_this, va_list *params)
	INIT_IFACE (Class, cbufCtor, cbufDtor, NULL)
	CREATE_CLASS (Cbuf, NULL, IFACE(Class))

Detailed Description

Author

Georg Hopp

Copyright

Copyright © 2012 Georg Hopp

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.

Definition in file cbuf.c.

Macro Definition Documentation

#define _GNU_SOURCE

Definition at line 25 of file cbuf.c.

#define _POSIX_C_SOURCE   200112L

Definition at line 24 of file cbuf.c.

#define _POSIX_SOURCE

Definition at line 23 of file cbuf.c.

Function Documentation

static int cbufCtor ( void *  _this, va_list *  params  )

static

align size at page boundary. increase as neccessary

Definition at line 46 of file cbuf.c.

References element::data, memMalloc(), and size.

{
    Cbuf   this     = _this;
    char   state    = -1;
    char * shm_name = va_arg(*params, char*);
    long   psize    = sysconf(_SC_PAGESIZE);
    size_t size;
    int    shm;
    char * data;

    this->shm_name = memMalloc(strlen(shm_name) + 7 + 2);
    sprintf(this->shm_name, "/%06d_%s", getpid(), shm_name);

    /**
     * align size at page boundary.
     * increase as neccessary
     */
    size        = va_arg(*params, size_t);
    size        = (0 >= size)? 1 : (0 != size%psize)? (size/psize)+1 : size/psize;
    this->bsize = psize * size;

    while (-1 == state) {
        shm = shm_open(this->shm_name, O_RDWR|O_CREAT|O_EXCL, S_IRWXU);
        if (-1 == shm) {
            break;
        }

        if (-1 == ftruncate(shm, this->bsize)) {
            break;
        }

        this->data = mmap (0, this->bsize << 1,
                PROT_NONE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);
        if (this->data == MAP_FAILED) {
            this->data = NULL;
            break;
        }   

        data = mmap (this->data, this->bsize,
                PROT_READ|PROT_WRITE, MAP_FIXED|MAP_SHARED, shm, 0);
        if (data != this->data) {
            break;
        }   

        data = mmap (this->data + this->bsize, this->bsize,
                PROT_READ|PROT_WRITE, MAP_FIXED|MAP_SHARED, shm, 0);
        if (data != this->data + this->bsize) {
            break;
        }   

        state = 0;
    }

    if (-1 != shm) {
        shm_unlink(this->shm_name);
        close(shm);
    }

    return state;
}

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static void cbufDtor ( void *  _this )

static

Definition at line 109 of file cbuf.c.

References element::data, and MEM_FREE.

{
    Cbuf this = _this;

    MEM_FREE(this->shm_name);

    if (NULL != this->data && MAP_FAILED != this->data) {
        munmap(this->data, this->bsize << 1);
    }

    this->data = NULL;
}

CREATE_CLASS	(	Cbuf	,
		NULL	,
		IFACE(Class)
	)

INIT_IFACE	(	Class	,
		cbufCtor	,
		cbufDtor	,
		NULL
	)