int shm_common_exists(int key)
{
struct shm_status sm;
int retval;
if (shmdrv_loaded) {
memset(&sm, 0, sizeof(struct shm_status));
sm.driver_fd = shmdrv_driver_fd();
sm.key = key;
sm.flags = 0;
retval = shmdrv_status(&sm);
close(sm.driver_fd);
return retval == 0;
} else {
int shmfd;
char segment_name[LINELEN];
sprintf(segment_name, SHM_FMT, INSTANCE_OF(key), key);
if ((shmfd = shm_open(segment_name, O_RDWR,
(S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP))) < 0) {
retval = 0;
} else {
close(shmfd);
retval = 1;
}
return retval;
}
}
int shmdrv_gc(void)
{
int retval;
int fd = shmdrv_driver_fd();
if (fd < 0)
return fd;
retval = ioctl(fd, IOC_SHM_GC, NULL);
close(fd);
return retval;
}
int _rtapi_shmem_new_inst(int userkey, int instance, int module_id, unsigned long int size) {
int n, retval;
int shmem_id;
shmem_data *shmem;
struct shm_status sm;
int key = OS_KEY(userkey, instance);
/* key must be non-zero, and also cannot match the key that RTAPI uses */
if ((key == 0) || (key == OS_KEY(RTAPI_KEY, instance))) {
rtapi_print_msg(RTAPI_MSG_ERR, "RTAPI: ERROR: bad shmem key: %d\n",
key);
return -EINVAL;
}
/* get the mutex */
rtapi_mutex_get(&(rtapi_data->mutex));
/* validate module_id */
if ((module_id < 1) || (module_id > RTAPI_MAX_MODULES)) {
rtapi_mutex_give(&(rtapi_data->mutex));
rtapi_print_msg(RTAPI_MSG_ERR, "RTAPI: ERROR: bad module ID: %d\n",
module_id);
return -EINVAL;
}
if (module_array[module_id].state != MODULE_STATE) {
rtapi_print_msg(RTAPI_MSG_ERR,
"RTAPI: ERROR: not a " OUR_API " module ID: %d\n",
module_id);
rtapi_mutex_give(&(rtapi_data->mutex));
return -EINVAL;
}
/* check if a block is already open for this key */
for (n = 1; n <= RTAPI_MAX_SHMEMS; n++) {
if (shmem_array[n].key == key) {
/* found a match */
shmem_id = n;
shmem = &(shmem_array[n]);
/* is it big enough? */
if (shmem->size < size) {
rtapi_mutex_give(&(rtapi_data->mutex));
rtapi_print_msg(RTAPI_MSG_ERR,
"RTAPI: ERROR: shmem size mismatch\n");
return -EINVAL;
}
/* is this module already using it? */
if (rtapi_test_bit(module_id, shmem->bitmap)) {
rtapi_mutex_give(&(rtapi_data->mutex));
rtapi_print_msg(RTAPI_MSG_WARN,
"RTAPI: Warning: shmem already mapped\n");
return -EEXIST;
}
/* yes, has it been mapped into kernel space? */
#ifdef RTAPI
if (shmem->rtusers == 0) {
#endif
/* no, map it and save the address */
sm.key = key;
sm.size = size;
sm.flags = 0;
#ifdef ULAPI
sm.driver_fd = shmdrv_driver_fd();
#endif
retval = shmdrv_attach(&sm, &shmem_addr_array[shmem_id]);
if (retval < 0) {
rtapi_mutex_give(&(rtapi_data->mutex));
rtapi_print_msg(RTAPI_MSG_ERR,
"shmdrv attached failed key=0x%x size=%ld\n", key, size);
return retval;
}
if (shmem_addr_array[shmem_id] == NULL) {
rtapi_print_msg(RTAPI_MSG_ERR,
"RTAPI: ERROR: failed to map shmem\n");
rtapi_mutex_give(&(rtapi_data->mutex));
#ifdef ULAPI
check_memlock_limit("failed to map shmem");
#endif
return -ENOMEM;
}
#ifdef RTAPI
}
#endif
/* update usage data */
rtapi_set_bit(module_id, shmem->bitmap);
#ifdef ULAPI
shmem->ulusers++;
#else /* RTAPI */
shmem->rtusers++;
#endif /* RTAPI */
/* announce another user for this shmem */
rtapi_print_msg(RTAPI_MSG_DBG,
"RTAPI: shmem %02d opened by module %02d\n",
shmem_id, module_id);
/* done */
rtapi_mutex_give(&(rtapi_data->mutex));
return shmem_id;
}
}
/* find empty spot in shmem array */
n = 1;
while ((n <= RTAPI_MAX_SHMEMS) && (shmem_array[n].key != 0)) {
rtapi_print_msg(RTAPI_MSG_DBG, OUR_API ": shmem %d occupuied \n",n);
n++;
}
if (n > RTAPI_MAX_SHMEMS) {
/* no room */
rtapi_mutex_give(&(rtapi_data->mutex));
rtapi_print_msg(RTAPI_MSG_ERR, "RTAPI: ERROR: reached shmem limit %d\n",
n);
return -EMFILE;
}
/* we have space for the block data */
rtapi_print_msg(RTAPI_MSG_DBG, OUR_API ": using new shmem %d \n",n);
shmem_id = n;
shmem = &(shmem_array[n]);
/* get shared memory block from OS and save its address */
sm.key = key;
sm.size = size;
sm.flags = 0;
#ifdef ULAPI
sm.driver_fd = shmdrv_driver_fd();
#endif
retval = shmdrv_create(&sm);
if (retval < 0) {
rtapi_mutex_give(&(rtapi_data->mutex));
rtapi_print_msg(RTAPI_MSG_ERR,"shmdrv create failed key=0x%x size=%ld\n", key, size);
return retval;
}
retval = shmdrv_attach(&sm, &shmem_addr_array[shmem_id]);
if (retval < 0) {
rtapi_mutex_give(&(rtapi_data->mutex));
rtapi_print_msg(RTAPI_MSG_ERR,"shmdrv attached failed key=0x%x size=%ld\n", key, size);
return retval;
}
if (shmem_addr_array[shmem_id] == NULL) {
rtapi_mutex_give(&(rtapi_data->mutex));
rtapi_print_msg(RTAPI_MSG_ERR,
"RTAPI: ERROR: could not create shmem %d\n", n);
return -ENOMEM;
}
/* the block has been created, update data */
rtapi_set_bit(module_id, shmem->bitmap);
shmem->key = key;
#ifdef RTAPI
shmem->rtusers = 1;
shmem->ulusers = 0;
#else /* ULAPI */
shmem->rtusers = 0;
shmem->ulusers = 1;
#endif /* ULAPI */
shmem->size = size;
shmem->magic = SHMEM_MAGIC;
shmem->instance = instance;
rtapi_data->shmem_count++;
/* zero the first word of the shmem area */
*((long int *) (shmem_addr_array[shmem_id])) = 0;
/* announce the birth of a brand new baby shmem */
rtapi_print_msg(RTAPI_MSG_DBG,
"RTAPI: shmem %02d created by module %02d, key: %d, size: %lu\n",
shmem_id, module_id, key, size);
/* and return the ID to the proud parent */
rtapi_mutex_give(&(rtapi_data->mutex));
return shmem_id;
}
int shm_common_new(int key, int *size, int instance, void **shmptr, int create)
{
struct shm_status sm;
int retval;
int is_new = 0;
if (shmdrv_loaded) {
// use shmdrv kernel driver
sm.driver_fd = shmdrv_driver_fd();
sm.key = key;
sm.size = (size == NULL? 0: *size);
sm.flags = 0;
retval = shmdrv_status(&sm); // check if exists
if (retval && !create) {
// didnt exist, but just attach requested, so fail
close(sm.driver_fd);
return -ENOENT;
}
if (retval) { // didnt exist, so create
retval = shmdrv_create(&sm);
if (retval < 0) {
return retval;
}
is_new = 1;
}
// now attach
retval = shmdrv_attach(&sm, shmptr);
if (retval < 0) {
close(sm.driver_fd);
return retval;
}
// if size was passed in as 0 (attach), fill in actual size
if (size && (*size == 0))
*size = sm.size;
close(sm.driver_fd);
return is_new;
} else {
// use POSIX shared memory
int shmfd, mmap_size;
mode_t old_umask;
char segment_name[LINELEN];
if ((size == 0) || (*size == 0))
mmap_size = 0;
else
mmap_size = *size;
sprintf(segment_name, SHM_FMT, instance, key);
old_umask = umask(0); //S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP);
if (create && ((shmfd = shm_open(segment_name,
(O_CREAT | O_EXCL | O_RDWR),
(S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP))) > 0)) {
// initial creation
if (fchown(shmfd, getuid(),getgid()))
perror("fchown");
if (ftruncate(shmfd, mmap_size))
perror("ftruncate");
is_new = 1;
} else if((shmfd = shm_open(segment_name, O_RDWR,
(S_IRUSR|S_IWUSR|S_IRGRP|S_IWGRP))) < 0) {
// just attach, and that failed:
umask(old_umask);
return -errno;
} else { // shmfd open
if (mmap_size == 0) {
struct stat st;
if (fstat(shmfd, &st)) {
perror("fstat");
return -errno;
}
mmap_size = st.st_size;
}
}
if((*shmptr = mmap(0, mmap_size, (PROT_READ | PROT_WRITE),
MAP_SHARED, shmfd, 0)) == MAP_FAILED) {
perror("shm_common_new:mmap");
close(shmfd);
umask(old_umask);
return -errno;
}
if (size) // return actual shm size as determined in attach
*size = mmap_size;
umask(old_umask);
close(shmfd);
return is_new;
}
}
