265 lines
8.8 KiB
C
265 lines
8.8 KiB
C
/****************************************************************************
|
|
* mm/shm/shmctl.c
|
|
*
|
|
* Copyright (C) 2014, 2017 Gregory Nutt. All rights reserved.
|
|
* Author: Gregory Nutt <gnutt@nuttx.org>
|
|
*
|
|
* Redistribution and use in source and binary forms, with or without
|
|
* modification, are permitted provided that the following conditions
|
|
* are met:
|
|
*
|
|
* 1. Redistributions of source code must retain the above copyright
|
|
* notice, this list of conditions and the following disclaimer.
|
|
* 2. Redistributions in binary form must reproduce the above copyright
|
|
* notice, this list of conditions and the following disclaimer in
|
|
* the documentation and/or other materials provided with the
|
|
* distribution.
|
|
* 3. Neither the name NuttX nor the names of its contributors may be
|
|
* used to endorse or promote products derived from this software
|
|
* without specific prior written permission.
|
|
*
|
|
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
|
|
* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
|
|
* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
|
|
* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
|
|
* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
|
|
* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
|
|
* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
|
|
* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
|
|
* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
|
|
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
|
|
* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
* POSSIBILITY OF SUCH DAMAGE.
|
|
*
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Included Files
|
|
****************************************************************************/
|
|
|
|
#include <nuttx/config.h>
|
|
|
|
#include <sys/shm.h>
|
|
#include <sys/ipc.h>
|
|
#include <unistd.h>
|
|
#include <string.h>
|
|
#include <time.h>
|
|
#include <errno.h>
|
|
#include <assert.h>
|
|
|
|
#include <nuttx/mm/shm.h>
|
|
#include <nuttx/pgalloc.h>
|
|
|
|
#include "shm/shm.h"
|
|
|
|
#ifdef CONFIG_MM_SHM
|
|
|
|
/****************************************************************************
|
|
* Public Functions
|
|
****************************************************************************/
|
|
|
|
/****************************************************************************
|
|
* Name: shmctl
|
|
*
|
|
* Description:
|
|
* The shmctl() function provides a variety of shared memory control
|
|
* operations as specified by cmd. The following values for cmd are
|
|
* available:
|
|
*
|
|
* - IPC_STAT
|
|
* Place the current value of each member of the shmid_ds data
|
|
* structure associated with shmid into the structure pointed to by
|
|
* buf.
|
|
* - IPC_SET
|
|
* Set the value of the shm_perm.mode member of the shmid_ds data
|
|
* structure associated with shmid to the corresponding value found
|
|
* in the structure pointed to by buf.
|
|
* - IPC_RMID
|
|
* Remove the shared memory identifier specified by shmid from the
|
|
* system and destroy the shared memory segment and shmid_ds data
|
|
* structure associated with it.
|
|
*
|
|
* Input Parameters:
|
|
* shmid - Shared memory identifier
|
|
* cmd - shmctl() command
|
|
* buf - Data associated with the shmctl() command
|
|
*
|
|
* Returned Value:
|
|
* Upon successful completion, shmctl() will return 0; otherwise, it will
|
|
* return -1 and set errno to indicate the error.
|
|
*
|
|
* - EACCES
|
|
* The argument cmd is equal to IPC_STAT and the calling process does
|
|
* not have read permission.
|
|
* - EINVAL
|
|
* The value of shmid is not a valid shared memory identifier, or the
|
|
* value of cmd is not a valid command.
|
|
* - EPERM
|
|
* The argument cmd is equal to IPC_RMID or IPC_SET and the effective
|
|
* user ID of the calling process is not equal to that of a process
|
|
* with appropriate privileges and it is not equal to the value of
|
|
* shm_perm.cuid or shm_perm.uid in the data structure associated with
|
|
* shmid.
|
|
* - EOVERFLOW
|
|
* The cmd argument is IPC_STAT and the gid or uid value is too large
|
|
* to be stored in the structure pointed to by the buf argument.
|
|
*
|
|
* POSIX Deviations:
|
|
* - IPC_SET. Does not set the shm_perm.uid or shm_perm.gid
|
|
* members of the shmid_ds data structure associated with shmid
|
|
* because user and group IDs are not yet supported by NuttX
|
|
* - IPC_SET. Does not restrict the operation to processes with
|
|
* appropriate privileges or matching user IDs in shmid_ds data
|
|
* structure associated with shmid. Again because user IDs and
|
|
* user/group privileges are are not yet supported by NuttX
|
|
* - IPC_RMID. Does not restrict the operation to processes with
|
|
* appropriate privileges or matching user IDs in shmid_ds data
|
|
* structure associated with shmid. Again because user IDs and
|
|
* user/group privileges are are not yet supported by NuttX
|
|
*
|
|
****************************************************************************/
|
|
|
|
int shmctl(int shmid, int cmd, struct shmid_ds *buf)
|
|
{
|
|
FAR struct shm_region_s *region;
|
|
int ret;
|
|
|
|
DEBUGASSERT(shmid >= 0 && shmid < CONFIG_ARCH_SHM_MAXREGIONS);
|
|
region = &g_shminfo.si_region[shmid];
|
|
DEBUGASSERT((region->sr_flags & SRFLAG_INUSE) != 0);
|
|
|
|
/* Get exclusive access to the region data structure */
|
|
|
|
ret = nxsem_wait(®ion->sr_sem);
|
|
if (ret < 0)
|
|
{
|
|
shmerr("ERROR: nxsem_wait failed: %d\n", ret);
|
|
goto errout_with_ret;
|
|
}
|
|
|
|
/* Handle the request according to the received cmd */
|
|
|
|
switch (cmd)
|
|
{
|
|
case IPC_STAT:
|
|
{
|
|
/* Place the current value of each member of the shmid_ds data
|
|
* structure associated with shmid into the structure pointed to
|
|
* by buf.
|
|
*/
|
|
|
|
DEBUGASSERT(buf);
|
|
memcpy(buf, ®ion->sr_ds, sizeof(struct shmid_ds));
|
|
}
|
|
break;
|
|
|
|
case IPC_SET:
|
|
{
|
|
/* Set the value of the shm_perm.mode member of the shmid_ds
|
|
* data structure associated with shmid to the corresponding
|
|
* value found in the structure pointed to by buf.
|
|
*/
|
|
|
|
region->sr_ds.shm_perm.mode = buf->shm_perm.mode;
|
|
}
|
|
break;
|
|
|
|
case IPC_RMID:
|
|
{
|
|
/* Are any processes attached to the region? */
|
|
|
|
if (region->sr_ds.shm_nattch > 0)
|
|
{
|
|
/* Yes.. just set the UNLINKED flag. The region will be
|
|
* removed when there are no longer any processes attached to
|
|
* it.
|
|
*/
|
|
|
|
region->sr_flags |= SRFLAG_UNLINKED;
|
|
}
|
|
else
|
|
{
|
|
/* No.. free the entry now */
|
|
|
|
shm_destroy(shmid);
|
|
|
|
/* Don't try anything further on the deleted region */
|
|
|
|
return OK;
|
|
}
|
|
}
|
|
break;
|
|
|
|
default:
|
|
shmerr("ERROR: Unrecognized command: %d\n", cmd);
|
|
ret = -EINVAL;
|
|
goto errout_with_semaphore;
|
|
}
|
|
|
|
/* Save the process ID of the last operation */
|
|
|
|
region = &g_shminfo.si_region[shmid];
|
|
region->sr_ds.shm_lpid = getpid();
|
|
|
|
/* Save the time of the last shmctl() */
|
|
|
|
region->sr_ds.shm_ctime = time(NULL);
|
|
|
|
/* Release our lock on the entry */
|
|
|
|
nxsem_post(®ion->sr_sem);
|
|
return ret;
|
|
|
|
errout_with_semaphore:
|
|
nxsem_post(®ion->sr_sem);
|
|
|
|
errout_with_ret:
|
|
set_errno(-ret);
|
|
return ERROR;
|
|
}
|
|
|
|
/****************************************************************************
|
|
* Name: shm_destroy
|
|
*
|
|
* Description:
|
|
* Destroy a memory region. This function is called:
|
|
*
|
|
* - On certain conditions when shmget() is not successful in instantiating
|
|
* the full memory region and we need to clean up and free a table entry.
|
|
* - When shmctl() is called with cmd == IPC_RMID and there are no
|
|
* processes attached to the memory region.
|
|
* - When shmdt() is called after the last process detaches from memory
|
|
* region after it was previously marked for deletion by shmctl().
|
|
*
|
|
* Input Parameters:
|
|
* shmid - Shared memory identifier
|
|
*
|
|
* Returned Value:
|
|
* None
|
|
*
|
|
* Assumption:
|
|
* The caller holds either the region table semaphore or else the
|
|
* semaphore on the particular entry being deleted.
|
|
*
|
|
****************************************************************************/
|
|
|
|
void shm_destroy(int shmid)
|
|
{
|
|
FAR struct shm_region_s *region = &g_shminfo.si_region[shmid];
|
|
int i;
|
|
|
|
/* Free all of the allocated physical pages */
|
|
|
|
for (i = 0; i < CONFIG_ARCH_SHM_NPAGES && region->sr_pages[i] != 0; i++)
|
|
{
|
|
mm_pgfree(region->sr_pages[i], 1);
|
|
}
|
|
|
|
/* Reset the region entry to its initial state */
|
|
|
|
nxsem_destroy(®ion->sr_sem);
|
|
memset(region, 0, sizeof(struct shm_region_s));
|
|
}
|
|
|
|
#endif /* CONFIG_MM_SHM */
|