/****************************************************************************
* fs/procfs/fs_procfscpuload.c
*
* Copyright (C) 2014 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/types.h>
#include <sys/statfs.h>
#include <sys/stat.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <string.h>
#include <fcntl.h>
#include <assert.h>
#include <errno.h>
#include <debug.h>
#include <nuttx/clock.h>
#include <nuttx/kmalloc.h>
#include <nuttx/fs/fs.h>
#include <nuttx/fs/procfs.h>
#if !defined(CONFIG_DISABLE_MOUNTPOINT) && defined(CONFIG_FS_PROCFS)
#if defined(CONFIG_SCHED_CPULOAD) && !defined(CONFIG_FS_PROCFS_EXCLUDE_CPULOAD)
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Determines the size of an intermediate buffer that must be large enough
* to handle the longest line generated by this logic.
*/
#define CPULOAD_LINELEN 16
/****************************************************************************
* Private Types
****************************************************************************/
/* This structure describes one open "file" */
struct cpuload_file_s
{
struct procfs_file_s base; /* Base open file structure */
unsigned int linesize; /* Number of valid characters in line[] */
char line[CPULOAD_LINELEN]; /* Pre-allocated buffer for formatted lines */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* File system methods */
static int cpuload_open(FAR struct file *filep, FAR const char *relpath,
int oflags, mode_t mode);
static int cpuload_close(FAR struct file *filep);
static ssize_t cpuload_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static int cpuload_dup(FAR const struct file *oldp,
FAR struct file *newp);
static int cpuload_stat(FAR const char *relpath, FAR struct stat *buf);
/****************************************************************************
* Private Variables
****************************************************************************/
/****************************************************************************
* Public Variables
****************************************************************************/
/* See fs_mount.c -- this structure is explicitly externed there.
* We use the old-fashioned kind of initializers so that this will compile
* with any compiler.
*/
const struct procfs_operations cpuload_operations =
{
cpuload_open, /* open */
cpuload_close, /* close */
cpuload_read, /* read */
NULL, /* write */
cpuload_dup, /* dup */
NULL, /* opendir */
NULL, /* closedir */
NULL, /* readdir */
NULL, /* rewinddir */
cpuload_stat /* stat */
};
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: cpuload_open
****************************************************************************/
static int cpuload_open(FAR struct file *filep, FAR const char *relpath,
int oflags, mode_t mode)
{
FAR struct cpuload_file_s *attr;
fvdbg("Open '%s'\n", relpath);
/* PROCFS is read-only. Any attempt to open with any kind of write
* access is not permitted.
*
* REVISIT: Write-able proc files could be quite useful.
*/
if ((oflags & O_WRONLY) != 0 || (oflags & O_RDONLY) == 0)
{
fdbg("ERROR: Only O_RDONLY supported\n");
return -EACCES;
}
/* "cpuload" is the only acceptable value for the relpath */
if (strcmp(relpath, "cpuload") != 0)
{
fdbg("ERROR: relpath is '%s'\n", relpath);
return -ENOENT;
}
/* Allocate a container to hold the file attributes */
attr = (FAR struct cpuload_file_s *)kmm_zalloc(sizeof(struct cpuload_file_s));
if (!attr)
{
fdbg("ERROR: Failed to allocate file attributes\n");
return -ENOMEM;
}
/* Save the attributes as the open-specific state in filep->f_priv */
filep->f_priv = (FAR void *)attr;
return OK;
}
/****************************************************************************
* Name: cpuload_close
****************************************************************************/
static int cpuload_close(FAR struct file *filep)
{
FAR struct cpuload_file_s *attr;
/* Recover our private data from the struct file instance */
attr = (FAR struct cpuload_file_s *)filep->f_priv;
DEBUGASSERT(attr);
/* Release the file attributes structure */
kmm_free(attr);
filep->f_priv = NULL;
return OK;
}
/****************************************************************************
* Name: cpuload_read
****************************************************************************/
static ssize_t cpuload_read(FAR struct file *filep, FAR char *buffer,
size_t buflen)
{
FAR struct cpuload_file_s *attr;
size_t linesize;
off_t offset;
ssize_t ret;
fvdbg("buffer=%p buflen=%d\n", buffer, (int)buflen);
/* Recover our private data from the struct file instance */
attr = (FAR struct cpuload_file_s *)filep->f_priv;
DEBUGASSERT(attr);
/* If f_pos is zero, then sample the system time. Otherwise, use
* the cached system time from the previous read(). It is necessary
* save the cached value in case, for example, the user is reading
* the time one byte at a time. In that case, the time must remain
* stable throughout the reads.
*/
if (filep->f_pos == 0)
{
struct cpuload_s cpuload;
uint32_t intpart;
uint32_t fracpart;
/* Sample the counts for the IDLE thread. clock_cpuload should only
* fail if the PID is not valid. This, however, should never happen
* for the IDLE thread.
*/
DEBUGVERIFY(clock_cpuload(0, &cpuload));
/* On the simulator, you may hit cpuload.total == 0, but probably never on
* real hardware.
*/
if (cpuload.total > 0)
{
uint32_t tmp;
tmp = 1000 - (1000 * cpuload.active) / cpuload.total;
intpart = tmp / 10;
fracpart = tmp - 10 * intpart;
}
else
{
intpart = 0;
fracpart = 0;
}
linesize = snprintf(attr->line, CPULOAD_LINELEN, "%3d.%01d%%",
intpart, fracpart);
/* Save the linesize in case we are re-entered with f_pos > 0 */
attr->linesize = linesize;
}
/* Transfer the system up time to user receive buffer */
offset = filep->f_pos;
ret = procfs_memcpy(attr->line, attr->linesize, buffer, buflen, &offset);
/* Update the file offset */
if (ret > 0)
{
filep->f_pos += ret;
}
return ret;
}
/****************************************************************************
* Name: cpuload_dup
*
* Description:
* Duplicate open file data in the new file structure.
*
****************************************************************************/
static int cpuload_dup(FAR const struct file *oldp, FAR struct file *newp)
{
FAR struct cpuload_file_s *oldattr;
FAR struct cpuload_file_s *newattr;
fvdbg("Dup %p->%p\n", oldp, newp);
/* Recover our private data from the old struct file instance */
oldattr = (FAR struct cpuload_file_s *)oldp->f_priv;
DEBUGASSERT(oldattr);
/* Allocate a new container to hold the task and attribute selection */
newattr = (FAR struct cpuload_file_s *)kmm_malloc(sizeof(struct cpuload_file_s));
if (!newattr)
{
fdbg("ERROR: Failed to allocate file attributes\n");
return -ENOMEM;
}
/* The copy the file attributes from the old attributes to the new */
memcpy(newattr, oldattr, sizeof(struct cpuload_file_s));
/* Save the new attributes in the new file structure */
newp->f_priv = (FAR void *)newattr;
return OK;
}
/****************************************************************************
* Name: cpuload_stat
*
* Description: Return information about a file or directory
*
****************************************************************************/
static int cpuload_stat(const char *relpath, struct stat *buf)
{
/* "cpuload" is the only acceptable value for the relpath */
if (strcmp(relpath, "cpuload") != 0)
{
fdbg("ERROR: relpath is '%s'\n", relpath);
return -ENOENT;
}
/* "cpuload" is the name for a read-only file */
buf->st_mode = S_IFREG|S_IROTH|S_IRGRP|S_IRUSR;
buf->st_size = 0;
buf->st_blksize = 0;
buf->st_blocks = 0;
return OK;
}
/****************************************************************************
* Public Functions
****************************************************************************/
#endif /* CONFIG_FS_PROCFS_EXCLUDE_CPULOAD */
#endif /* !CONFIG_DISABLE_MOUNTPOINT && CONFIG_FS_PROCFS */
