/* SPDX-License-Identifier: BSD-2-Clause */
/**
* @file
*/
/*
* Copyright (c) 2016 Gedare Bloom.
*
* 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.
*
* 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.
*/
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <sys/mman.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#include <sys/stat.h>
#include <rtems/libio_.h>
#include <rtems/seterr.h>
#include <rtems/posix/shmimpl.h>
#include <rtems/score/wkspace.h>
#include <rtems/sysinit.h>
static const rtems_filesystem_file_handlers_r shm_handlers;
static int shm_fstat(
const rtems_filesystem_location_info_t *loc,
struct stat *buf
)
{
POSIX_Shm_Control *shm = loc_to_shm( loc );
if ( shm == NULL )
rtems_set_errno_and_return_minus_one( EIO );
/* mandatory for shm objects */
buf->st_uid = shm->uid;
buf->st_gid = shm->gid;
buf->st_size = shm->shm_object.size;
buf->st_mode = shm->mode;
/* optional for shm objects */
buf->st_atime = shm->atime;
buf->st_mtime = shm->mtime;
buf->st_ctime = shm->ctime;
return 0;
}
/* read() is unspecified for shared memory objects */
static ssize_t shm_read( rtems_libio_t *iop, void *buffer, size_t count )
{
ssize_t bytes_read;
POSIX_Shm_Control *shm = iop_to_shm( iop );
_Objects_Allocator_lock();
bytes_read = (*shm->shm_object.ops->object_read)(
&shm->shm_object,
buffer,
count
);
_POSIX_Shm_Update_atime( shm );
_Objects_Allocator_unlock();
return bytes_read;
}
static int shm_ftruncate( rtems_libio_t *iop, off_t length )
{
int err;
POSIX_Shm_Control *shm = iop_to_shm( iop );
_Objects_Allocator_lock();
err = (*shm->shm_object.ops->object_resize)( &shm->shm_object, length );
if ( err != 0 ) {
_Objects_Allocator_unlock();
rtems_set_errno_and_return_minus_one( err );
}
_POSIX_Shm_Update_mtime_ctime( shm );
_Objects_Allocator_unlock();
return 0;
}
static int shm_close( rtems_libio_t *iop )
{
POSIX_Shm_Control *shm = iop_to_shm( iop );
int err;
err = 0;
POSIX_Shm_Attempt_delete(shm);
iop->pathinfo.node_access = NULL;
if ( err != 0 ) {
rtems_set_errno_and_return_minus_one( err );
}
return 0;
}
static int shm_mmap(
rtems_libio_t *iop,
void** addr,
size_t len,
int prot,
off_t off
)
{
POSIX_Shm_Control *shm = iop_to_shm( iop );
_Objects_Allocator_lock();
*addr = (*shm->shm_object.ops->object_mmap)( &shm->shm_object, len, prot, off);
if ( *addr != NULL ) {
/* Keep a reference in the shared memory to prevent its removal. */
++shm->reference_count;
/* Update atime */
_POSIX_Shm_Update_atime(shm);
} else {
_Objects_Allocator_unlock();
rtems_set_errno_and_return_minus_one( ENOMEM );
}
_Objects_Allocator_unlock();
return 0;
}
static inline POSIX_Shm_Control *shm_allocate(
const char *name_arg,
size_t name_len,
int oflag,
mode_t mode,
int *error
)
{
POSIX_Shm_Control *shm;
char *name;
struct timeval tv;
/* Reject any name without a leading slash. */
if ( name_arg[0] != '/' ) {
*error = EINVAL;
return NULL;
}
/* Only create the object if requested. */
if ( ( oflag & O_CREAT ) != O_CREAT ) {
*error = ENOENT;
return NULL;
}
name = _Workspace_String_duplicate( name_arg, name_len );
if ( name == NULL ) {
*error = ENOSPC;
return NULL;
}
shm = _POSIX_Shm_Allocate_unprotected();
if ( shm == NULL ) {
_Workspace_Free( name );
*error = ENFILE;
return NULL;
}
gettimeofday( &tv, 0 );
shm->reference_count = 1;
shm->shm_object.handle = NULL;
shm->shm_object.size = 0;
shm->shm_object.ops = &_POSIX_Shm_Object_operations;
shm->mode = mode & ~rtems_filesystem_umask;
shm->oflag = oflag;
shm->uid = geteuid();
shm->gid = getegid();
shm->atime = (time_t) tv.tv_sec;
shm->mtime = (time_t) tv.tv_sec;
shm->ctime = (time_t) tv.tv_sec;
_Objects_Open_string( &_POSIX_Shm_Information, &shm->Object, name );
return shm;
}
static inline bool shm_access_ok( POSIX_Shm_Control *shm, int oflag )
{
int flags;
if ( (oflag & O_ACCMODE) == O_RDONLY ) {
flags = RTEMS_FS_PERMS_READ;
} else {
flags = RTEMS_FS_PERMS_WRITE;
}
return rtems_filesystem_check_access( flags, shm->mode, shm->uid, shm->gid );
}
static inline int shm_check_oflag( int oflag )
{
if ( ( oflag & O_ACCMODE ) != O_RDONLY && ( oflag & O_ACCMODE ) != O_RDWR ) {
rtems_set_errno_and_return_minus_one( EACCES );
}
if ( ( oflag & ~( O_RDONLY | O_RDWR | O_CREAT | O_EXCL | O_TRUNC ) ) != 0 ) {
rtems_set_errno_and_return_minus_one( EACCES );
}
if ( ( oflag & O_TRUNC ) != 0 && ( oflag & O_ACCMODE ) != O_RDWR ) {
rtems_set_errno_and_return_minus_one( EACCES );
}
return 0;
}
int shm_open( const char *name, int oflag, mode_t mode )
{
int err = 0;
int fd;
rtems_libio_t *iop;
POSIX_Shm_Control *shm;
size_t len;
Objects_Get_by_name_error obj_err;
unsigned int flags;
if ( shm_check_oflag( oflag ) != 0 ) {
return -1;
}
iop = rtems_libio_allocate();
if ( iop == NULL ) {
rtems_set_errno_and_return_minus_one( EMFILE );
}
_Objects_Allocator_lock();
shm = _POSIX_Shm_Get_by_name( name, &len, &obj_err );
if ( shm == NULL ) {
switch ( obj_err ) {
case OBJECTS_GET_BY_NAME_INVALID_NAME:
err = EINVAL;
break;
case OBJECTS_GET_BY_NAME_NAME_TOO_LONG:
err = ENAMETOOLONG;
break;
case OBJECTS_GET_BY_NAME_NO_OBJECT:
default:
shm = shm_allocate(name, len, oflag, mode, &err);
break;
}
} else { /* shm exists */
if ( ( oflag & ( O_EXCL | O_CREAT ) ) == ( O_EXCL | O_CREAT ) ) {
/* Request to create failed. */
err = EEXIST;
} else if ( !shm_access_ok( shm, oflag ) ) {
err = EACCES;
} else {
++shm->reference_count;
}
}
_Objects_Allocator_unlock();
if ( err != 0 ) {
rtems_libio_free( iop );
rtems_set_errno_and_return_minus_one( err );
}
if ( oflag & O_TRUNC ) {
err = shm_ftruncate( iop, 0 );
(void) err; /* ignore truncate error */
}
fd = rtems_libio_iop_to_descriptor( iop );
iop->data0 = fd;
iop->data1 = shm;
iop->pathinfo.node_access = shm;
iop->pathinfo.handlers = &shm_handlers;
iop->pathinfo.mt_entry = &rtems_filesystem_null_mt_entry;
rtems_filesystem_location_add_to_mt_entry( &iop->pathinfo );
flags = LIBIO_FLAGS_OPEN | LIBIO_FLAGS_CLOSE_ON_EXEC;
if ( (oflag & O_ACCMODE) == O_RDONLY ) {
flags |= LIBIO_FLAGS_READ;
} else {
flags |= LIBIO_FLAGS_READ_WRITE;
}
rtems_libio_iop_flags_set( iop, flags );
return fd;
}
static const rtems_filesystem_file_handlers_r shm_handlers = {
.open_h = rtems_filesystem_default_open,
.close_h = shm_close,
.read_h = shm_read,
.write_h = rtems_filesystem_default_write,
.ioctl_h = rtems_filesystem_default_ioctl,
.lseek_h = rtems_filesystem_default_lseek,
.fstat_h = shm_fstat,
.ftruncate_h = shm_ftruncate,
.fsync_h = rtems_filesystem_default_fsync_or_fdatasync,
.fdatasync_h = rtems_filesystem_default_fsync_or_fdatasync,
.fcntl_h = rtems_filesystem_default_fcntl,
.kqfilter_h = rtems_filesystem_default_kqfilter,
.mmap_h = shm_mmap,
.poll_h = rtems_filesystem_default_poll,
.readv_h = rtems_filesystem_default_readv,
.writev_h = rtems_filesystem_default_writev
};
static void _POSIX_Shm_Manager_initialization( void )
{
_Objects_Initialize_information( &_POSIX_Shm_Information );
}
RTEMS_SYSINIT_ITEM(
_POSIX_Shm_Manager_initialization,
RTEMS_SYSINIT_POSIX_SHM,
RTEMS_SYSINIT_ORDER_MIDDLE
);