/******************************************************************************
*
* Copyright (c) 2009 Citrix Systems, Inc. (Grzegorz Milos)
*
* 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 2 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, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <assert.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <sys/types.h>
#include "memshr-priv.h"
#include "bidir-hash.h"
#include "shm.h"
#define MEMSHR_INFO_SHM_FILE "/memshr-info"
#define MEMSHR_INFO_MAGIC 0x15263748
#define FGPRT_HASH_SHM_FILE "/blktap-fgprts"
#define FGPRT_HASH_PAGES 10000
#define BLOCK_HASH_SHM_FILE "/blktap-blks"
#define BLOCK_HASH_PAGES 10000
typedef struct shm_area {
void* base_addr;
size_t size;
int fd;
} shm_area_t;
typedef struct {
struct shm_area shared_info_area;
struct shm_area fgprts_area;
struct shm_area blocks_area;
} private_shm_info_t;
private_shm_info_t shm_info;
static int shm_area_open(const char *file, size_t size, int unlink, shm_area_t *shma)
{
/* TODO: If blktapctrl can be restarted while system is running, this needs
* to be cleverer */
if(unlink) shm_unlink(file);
shma->size = size;
shma->fd = shm_open(file,
(O_CREAT | O_RDWR),
(S_IREAD | S_IWRITE));
if(shma->fd < 0) return -1;
if(ftruncate(shma->fd, size) < 0) return -2;
shma->base_addr = mmap(NULL,
size,
PROT_READ | PROT_WRITE,
MAP_SHARED,
shma->fd,
0);
if(shma->base_addr == MAP_FAILED) return -2;
return 0;
}
static void shm_area_close(shm_area_t *shma)
{
munmap(shma->base_addr, shma->size);
close(shma->fd);
}
shared_memshr_info_t * shm_shared_info_open(int unlink)
{
shared_memshr_info_t *shared_info;
pthread_mutexattr_t lock_attr;
int nr_pages, i;
nr_pages = (sizeof(shared_memshr_info_t) >> XC_PAGE_SHIFT) + 1;
if(shm_area_open(MEMSHR_INFO_SHM_FILE,
nr_pages * XC_PAGE_SIZE,
unlink,
&(shm_info.shared_info_area)) < 0)
{
DPRINTF("Failed to open shma for shared info.\n");
return NULL;
}
shared_info = (shared_memshr_info_t *)
shm_info.shared_info_area.base_addr;
if(unlink)
{
memset(shared_info, 0, sizeof(shared_memshr_info_t));
if(pthread_mutexattr_init(&lock_attr) ||
pthread_mutexattr_setpshared(&lock_attr, PTHREAD_PROCESS_SHARED) ||
pthread_mutex_init(&shared_info->lock, &lock_attr) ||
pthread_mutexattr_destroy(&lock_attr))
{
DPRINTF("Failed to init shared info lock.\n");
return NULL;
}
strcpy(shared_info->vbd_images[0].file, "list-head");
for(i=1; i<MAX_NR_VBD_IMAGES; i++)
{
shared_info->vbd_images[i].next = i;
shared_info->vbd_images[i].prev = i;
}
shared_info->magic = MEMSHR_INFO_MAGIC;
}
else
if(shared_info->magic != MEMSHR_INFO_MAGIC)
{
DPRINTF("Incorrect magic in shared info.\n");
return NULL;
}
return shared_info;
}
struct fgprtshr_hash * shm_fgprtshr_hash_open(int unlink)
{
struct fgprtshr_hash *h;
if(shm_area_open(FGPRT_HASH_SHM_FILE,
FGPRT_HASH_PAGES * XC_PAGE_SIZE,
unlink,
&(shm_info.fgprts_area)) < 0)
{
DPRINTF("Failed to init shma for fgprtshr_hash.\n");
return NULL;
}
if(unlink)
{
h = fgprtshr_shm_hash_init(
(unsigned long) shm_info.fgprts_area.base_addr,
FGPRT_HASH_PAGES * XC_PAGE_SIZE);
} else
{
h = fgprtshr_shm_hash_get(
(unsigned long) shm_info.fgprts_area.base_addr);
}
return h;
}
struct blockshr_hash * shm_blockshr_hash_open(int unlink)
{
struct blockshr_hash *h;
if(shm_area_open(BLOCK_HASH_SHM_FILE,
BLOCK_HASH_PAGES * XC_PAGE_SIZE,
unlink,
&(shm_info.blocks_area)) < 0)
{
DPRINTF("Failed to init shma for blockshr_hash.\n");
return NULL;
}
if(unlink)
{
h = blockshr_shm_hash_init(
(unsigned long) shm_info.blocks_area.base_addr,
BLOCK_HASH_PAGES * XC_PAGE_SIZE);
} else
{
h = blockshr_shm_hash_get(
(unsigned long) shm_info.blocks_area.base_addr);
}
return h;
}
uint16_t shm_vbd_image_get(const char* file, vbd_image_info_t *vbd_imgs)
{
vbd_image_info_t *img, *next_img;
int i, img_id;
/* Try to find the file in the existing list first */
img = vbd_imgs;
while(img->next != 0)
{
img = vbd_imgs + img->next;
if(strncmp(img->file, file, MAX_NAME_LEN) == 0)
{
img->ref_cnt++;
return (uint16_t)(img - vbd_imgs);
}
}
/* Couldn't find an existing entry. We need to add one. Find empty slot */
for(i=1; i<MAX_NR_VBD_IMAGES; i++)
{
img = vbd_imgs + i;
if((img->next == i) && (img->prev == i))
break;
}
/* No entries left! */
if(i == MAX_NR_VBD_IMAGES)
{
DPRINTF("No space in vbds table.\n");
return 0;
}
if(strlen(file) > MAX_NAME_LEN)
{
DPRINTF("Filename: %s too long (>%d).\n", file, MAX_NAME_LEN);
return 0;
}
/* Init the entry */
img_id = (img - vbd_imgs);
next_img = vbd_imgs + vbd_imgs[0].next;
strcpy(img->file, file);
img->ref_cnt = 1;
img->next = vbd_imgs[0].next;
img->prev = 0;
next_img->prev = img_id;
vbd_imgs[0].next = img_id;
return img_id;
}
void shm_vbd_image_put(uint16_t memshr_id, vbd_image_info_t *vbd_imgs)
{
vbd_image_info_t *img, *next_img, *prev_img;
img = vbd_imgs + memshr_id;
if(img->ref_cnt == 0)
{
DPRINTF("Incorrect image put.\n");
return;
}
img->ref_cnt--;
/* Remove from list if ref_cnt is zero */
if(img->ref_cnt == 0)
{
next_img = vbd_imgs + img->next;
prev_img = vbd_imgs + img->prev;
prev_img->next = img->next;
next_img->prev = img->prev;
img->next = img->prev = (img - vbd_imgs);
memset(img->file, 0, MAX_NAME_LEN);
}
}
