incubator-nuttx/fs/procfs/fs_skeleton.c

503 lines
14 KiB
C

/****************************************************************************
* fs/procfs/fs_skeleton.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <fcntl.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/arch.h>
#include <nuttx/sched.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include <nuttx/fs/procfs.h>
#include <arch/irq.h>
#if !defined(CONFIG_DISABLE_MOUNTPOINT) && defined(CONFIG_FS_PROCFS)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/****************************************************************************
* Private Types
****************************************************************************/
/* This enumeration identifies all of the thread attributes that can be
* accessed via the procfs file system.
*/
/* This structure describes one open "file" */
struct skel_file_s
{
struct procfs_file_s base; /* Base open file structure */
/* Add context specific data types for managing an open file here */
};
/* Level 1 is the directory of attributes */
struct skel_level1_s
{
struct procfs_dir_priv_s base; /* Base directory private data */
/* Add context specific data types here for managing the directory
* open / read / stat, etc.
*/
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* File system methods */
static int skel_open(FAR struct file *filep, FAR const char *relpath,
int oflags, mode_t mode);
static int skel_close(FAR struct file *filep);
static ssize_t skel_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
/* TODO: Should not support skel_write if read-only */
static ssize_t skel_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen);
static int skel_dup(FAR const struct file *oldp,
FAR struct file *newp);
static int skel_opendir(FAR const char *relpath,
FAR struct fs_dirent_s **dir);
static int skel_closedir(FAR struct fs_dirent_s *dir);
static int skel_readdir(FAR struct fs_dirent_s *dir,
FAR struct dirent *entry);
static int skel_rewinddir(FAR struct fs_dirent_s *dir);
static int skel_stat(FAR const char *relpath, FAR struct stat *buf);
/****************************************************************************
* Private Data
****************************************************************************/
/****************************************************************************
* Public Data
****************************************************************************/
/* See include/nutts/fs/procfs.h
* We use the old-fashioned kind of initializers so that this will compile
* with any compiler.
*/
const struct procfs_operations skel_procfsoperations =
{
skel_open, /* open */
skel_close, /* close */
skel_read, /* read */
/* TODO: Decide if this procfs entry supports write access */
#if 0 /* NULL if the procfs entry does not support write access. */
NULL, /* write */
#else
skel_write, /* write */
#endif
NULL, /* poll */
skel_dup, /* dup */
skel_opendir, /* opendir */
skel_closedir, /* closedir */
skel_readdir, /* readdir */
skel_rewinddir, /* rewinddir */
skel_stat /* stat */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: skel_open
****************************************************************************/
static int skel_open(FAR struct file *filep, FAR const char *relpath,
int oflags, mode_t mode)
{
FAR struct skel_file_s *priv;
finfo("Open '%s'\n", relpath);
/* If PROCFS is read-only, then the (1) the skel_write() method must not
* be provided and (2) any attempt to open with any kind of write access
* can not be permitted.
*/
if (((oflags & O_WRONLY) != 0 || (oflags & O_RDONLY) == 0) &&
(skel_procfsoperations.write == NULL))
{
ferr("ERROR: Only O_RDONLY supported\n");
return -EACCES;
}
/* Allocate the open file structure */
priv = kmm_zalloc(sizeof(struct skel_file_s));
if (!priv)
{
ferr("ERROR: Failed to allocate file attributes\n");
return -ENOMEM;
}
/* TODO: Initialize the context specific data here */
/* Save the open file structure as the open-specific state in
* filep->f_priv.
*/
filep->f_priv = (FAR void *)priv;
return OK;
}
/****************************************************************************
* Name: skel_close
****************************************************************************/
static int skel_close(FAR struct file *filep)
{
FAR struct skel_file_s *priv;
/* Recover our private data from the struct file instance */
priv = (FAR struct skel_file_s *)filep->f_priv;
DEBUGASSERT(priv);
/* Release the file attributes structure */
kmm_free(priv);
filep->f_priv = NULL;
return OK;
}
/****************************************************************************
* Name: skel_read
*
* Description:
* Handle read from procfs file.
*
****************************************************************************/
static ssize_t skel_read(FAR struct file *filep, FAR char *buffer,
size_t buflen)
{
FAR struct skel_file_s *priv;
ssize_t ret;
finfo("buffer=%p buflen=%d\n", buffer, (int)buflen);
/* Recover our private data from the struct file instance */
priv = (FAR struct skel_file_s *)filep->f_priv;
DEBUGASSERT(priv);
/* TODO: Provide the requested data.
* Take into account current filep->f_pos and 'buflen'. The read
* could require several calls to skel_read().
*/
ret = 0;
/* Update the file offset */
if (ret > 0)
{
filep->f_pos += ret;
}
return ret;
}
/****************************************************************************
* Name: skel_write
*
* Description:
* Handle write3 to procfs file.
*
****************************************************************************/
/* TODO: Should not support skel_write if read-only */
static ssize_t skel_write(FAR struct file *filep, FAR const char *buffer,
size_t buflen)
{
FAR struct skel_file_s *priv;
ssize_t ret;
finfo("buffer=%p buflen=%d\n", buffer, (int)buflen);
/* Recover our private data from the struct file instance */
priv = (FAR struct skel_file_s *)filep->f_priv;
DEBUGASSERT(priv);
/* TODO: Verify that the write is within range */
/* TODO: Handle the write data as appropriate to function of file.
* Take into account current filep->f_pos and 'buflen' since the
* write may require several calls to skel_write().
*/
ret = 0;
/* Update the file offset */
if (ret > 0)
{
filep->f_pos += ret;
}
return ret;
}
/****************************************************************************
* Name: skel_dup
*
* Description:
* Duplicate open file data in the new file structure.
*
****************************************************************************/
static int skel_dup(FAR const struct file *oldp, FAR struct file *newp)
{
FAR struct skel_file_s *oldpriv;
FAR struct skel_file_s *newpriv;
finfo("Dup %p->%p\n", oldp, newp);
/* Recover our private data from the old struct file instance */
oldpriv = (FAR struct skel_file_s *)oldp->f_priv;
DEBUGASSERT(oldpriv);
/* Allocate a new container to hold the task and attribute selection */
newpriv = kmm_zalloc(sizeof(struct skel_file_s));
if (!newpriv)
{
ferr("ERROR: Failed to allocate file attributes\n");
return -ENOMEM;
}
/* The copy the file attribute from the old attributes to the new */
memcpy(newpriv, oldpriv, sizeof(struct skel_file_s));
/* Save the new attributes in the new file structure */
newp->f_priv = (FAR void *)newpriv;
return OK;
}
/****************************************************************************
* Name: skel_opendir
*
* Description:
* Open a directory for read access
*
****************************************************************************/
static int skel_opendir(FAR const char *relpath,
FAR struct fs_dirent_s **dir)
{
FAR struct skel_level1_s *level1;
finfo("relpath: \"%s\"\n", relpath ? relpath : "NULL");
DEBUGASSERT(relpath);
/* The path refers to the 1st level sbdirectory. Allocate the level1
* dirent structure.
*/
level1 = (FAR struct skel_level1_s *)
kmm_zalloc(sizeof(struct skel_level1_s));
if (!level1)
{
ferr("ERROR: Failed to allocate the level1 directory structure\n");
return -ENOMEM;
}
/* TODO: Initialize context specific data */
/* Initialize base structure components */
level1->base.level = 1;
level1->base.nentries = 0;
level1->base.index = 0;
*dir = (FAR struct fs_dirent_s *)level1;
return OK;
}
/****************************************************************************
* Name: skel_closedir
*
* Description: Close the directory listing
*
****************************************************************************/
static int skel_closedir(FAR struct fs_dirent_s *dir)
{
DEBUGASSERT(dir);
kmm_free(dir);
return OK;
}
/****************************************************************************
* Name: skel_readdir
*
* Description: Read the next directory entry
*
****************************************************************************/
static int skel_readdir(FAR struct fs_dirent_s *dir,
FAR struct dirent *entry)
{
FAR struct skel_level1_s *level1;
char filename[16];
int index;
int ret;
DEBUGASSERT(dir);
level1 = (FAR struct skel_level1_s *)dir;
/* TODO: Perform device specific readdir function here. This may
* or may not involve validating the nentries variable
* in the base depending on the implementation.
*/
/* Have we reached the end of the directory */
index = level1->base.index;
if (index >= level1->base.nentries)
{
/* We signal the end of the directory by returning the special
* error -ENOENT
*/
finfo("Entry %d: End of directory\n", index);
ret = -ENOENT;
}
/* We are traversing a subdirectory of task attributes */
else
{
DEBUGASSERT(level1->base.level == 1);
/* TODO: Add device specific entries */
strlcpy(filename, "dummy", sizeof(filename));
/* TODO: Specify the type of entry */
entry->d_type = DTYPE_FILE;
strlcpy(entry->d_name, filename, sizeof(entry->d_name));
/* Set up the next directory entry offset. NOTE that we could use the
* standard f_pos instead of our own private index.
*/
level1->base.index = index + 1;
ret = OK;
}
return ret;
}
/****************************************************************************
* Name: skel_rewindir
*
* Description: Reset directory read to the first entry
*
****************************************************************************/
static int skel_rewinddir(FAR struct fs_dirent_s *dir)
{
FAR struct skel_level1_s *priv;
DEBUGASSERT(dir);
priv = (FAR struct skel_level1_s *)dir;
priv->base.index = 0;
return OK;
}
/****************************************************************************
* Name: skel_stat
*
* Description: Return information about a file or directory
*
****************************************************************************/
static int skel_stat(FAR const char *relpath, FAR struct stat *buf)
{
int ret = -ENOENT;
/* TODO: Decide if the relpath is valid and if it is a file
* or a directory and set it's permissions.
*/
memset(buf, 0, sizeof(struct stat));
buf->st_mode = S_IFDIR | S_IROTH | S_IRGRP | S_IRUSR;
/* TODO: Set S_IFREG if the relpath refers to a file.
* TODO: If the skel_write() method is supported, then stat must also
* report S_IWOTH | S_IWGRP | S_IWUSR for files (but not for
* directories) as well.
* TODO: Other 'struct buf' settings may be appropriate (optional)
*/
ret = OK;
return ret;
}
/****************************************************************************
* Public Functions
****************************************************************************/
#endif /* !CONFIG_DISABLE_MOUNTPOINT && CONFIG_FS_PROCFS */