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incubator-nuttx/drivers/syslog/ramlog.c

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/****************************************************************************
* drivers/syslog/ramlog.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/ioctl.h>
#include <stdio.h>
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>
#include <fcntl.h>
#include <string.h>
#include <poll.h>
#include <errno.h>
#include <assert.h>
#include <debug.h>
#include <ctype.h>
#include <sys/boardctl.h>
#include <nuttx/arch.h>
#include <nuttx/kmalloc.h>
#include <nuttx/spinlock.h>
#include <nuttx/semaphore.h>
#include <nuttx/fs/fs.h>
#include <nuttx/fs/ioctl.h>
#include <nuttx/syslog/ramlog.h>
#include <nuttx/compiler.h>
#include <nuttx/list.h>
#include <nuttx/irq.h>
#ifdef CONFIG_RAMLOG
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
#define RAMLOG_MAGIC_NUMBER 0x12345678
/****************************************************************************
* Private Types
****************************************************************************/
struct ramlog_header_s
{
uint32_t rl_magic; /* The rl_magic number for ramlog buffer init */
volatile uint32_t rl_head; /* The head index (where data is added,natural growth) */
char rl_buffer[]; /* Circular RAM buffer */
};
struct ramlog_user_s
{
struct list_node rl_node; /* The list_node of reader */
volatile uint32_t rl_tail; /* The tail index (where data is removed) */
uint32_t rl_threashold; /* The threashold of the reader to read log */
#ifndef CONFIG_RAMLOG_NONBLOCKING
sem_t rl_waitsem; /* Used to wait for data */
#endif
/* The following the poll structures of threads waiting for driver events.
* The 'struct pollfd' reference for each open is also retained in the
* f_priv field of the 'struct file'.
*/
FAR struct pollfd *rl_fds;
};
struct ramlog_dev_s
{
/* The following is the header of the RAM buffer,
* Store the RAM BUFFER init rl_magic number,
* and read/write pointers
*/
FAR struct ramlog_header_s *rl_header;
uint32_t rl_bufsize; /* Size of the Circular RAM buffer */
struct list_node rl_list; /* The head of ramlog_user_s list */
};
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
/* Helper functions */
#ifndef CONFIG_RAMLOG_NONBLOCKING
static void ramlog_readnotify(FAR struct ramlog_dev_s *priv);
#endif
static void ramlog_pollnotify(FAR struct ramlog_dev_s *priv);
/* Character driver methods */
static int ramlog_file_open(FAR struct file *filep);
static int ramlog_file_close(FAR struct file *filep);
static ssize_t ramlog_file_read(FAR struct file *filep, FAR char *buffer,
size_t buflen);
static ssize_t ramlog_file_write(FAR struct file *filep,
FAR const char *buffer, size_t buflen);
static int ramlog_file_ioctl(FAR struct file *filep, int cmd,
unsigned long arg);
static int ramlog_file_poll(FAR struct file *filep,
FAR struct pollfd *fds, bool setup);
/****************************************************************************
* Private Data
****************************************************************************/
static const struct file_operations g_ramlogfops =
{
ramlog_file_open, /* open */
ramlog_file_close, /* close */
ramlog_file_read, /* read */
ramlog_file_write, /* write */
NULL, /* seek */
ramlog_file_ioctl, /* ioctl */
NULL, /* mmap */
NULL, /* truncate */
ramlog_file_poll /* poll */
};
/* This is the pre-allocated buffer used for the console RAM log and/or
* for the syslogging function.
*/
#ifdef CONFIG_RAMLOG_SYSLOG
# ifdef RAMLOG_BUFFER_SECTION
static uint32_t g_sysbuffer[CONFIG_RAMLOG_BUFSIZE / 4]
locate_data(RAMLOG_BUFFER_SECTION);
# else
static uint32_t g_sysbuffer[CONFIG_RAMLOG_BUFSIZE / 4];
# endif
/* This is the device structure for the console or syslogging function. It
* must be statically initialized because the RAMLOG ramlog_putc function
* could be called before the driver initialization logic executes.
*/
static struct ramlog_dev_s g_sysdev =
{
(FAR struct ramlog_header_s *)g_sysbuffer, /* rl_buffer */
sizeof(g_sysbuffer) - sizeof(struct ramlog_header_s), /* rl_bufsize */
LIST_INITIAL_VALUE(g_sysdev.rl_list) /* rl_list */
};
#endif
/****************************************************************************
* Private Functions
****************************************************************************/
/****************************************************************************
* Name: ramlog_bufferused
****************************************************************************/
static uint32_t ramlog_bufferused(FAR struct ramlog_dev_s *priv,
FAR struct ramlog_user_s *upriv)
{
uint32_t used = priv->rl_header->rl_head - upriv->rl_tail;
return used > priv->rl_bufsize ? priv->rl_bufsize : used;
}
/****************************************************************************
* Name: ramlog_readnotify
****************************************************************************/
#ifndef CONFIG_RAMLOG_NONBLOCKING
static void ramlog_readnotify(FAR struct ramlog_dev_s *priv)
{
FAR struct ramlog_user_s *upriv;
/* Notify all waiting readers that they can read from the FIFO */
list_for_every_entry(&priv->rl_list, upriv, struct ramlog_user_s, rl_node)
{
for (; ; )
{
int semcount = 0;
nxsem_get_value(&upriv->rl_waitsem, &semcount);
if (semcount >= 0)
{
break;
}
nxsem_post(&upriv->rl_waitsem);
}
}
}
#endif
/****************************************************************************
* Name: ramlog_pollnotify
****************************************************************************/
static void ramlog_pollnotify(FAR struct ramlog_dev_s *priv)
{
FAR struct ramlog_user_s *upriv;
/* This function may be called from an interrupt handler */
list_for_every_entry(&priv->rl_list, upriv, struct ramlog_user_s, rl_node)
{
if (ramlog_bufferused(priv, upriv) >= upriv->rl_threashold)
{
/* Notify all poll/select waiters that they can read from
* the FIFO
*/
poll_notify(&upriv->rl_fds, 1, POLLIN);
}
}
}
/****************************************************************************
* Name: ramlog_flush
****************************************************************************/
static void ramlog_bufferflush(FAR struct ramlog_dev_s *priv)
{
FAR struct ramlog_user_s *upriv;
priv->rl_header->rl_head = 0;
list_for_every_entry(&priv->rl_list, upriv, struct ramlog_user_s, rl_node)
{
upriv->rl_tail = 0;
}
}
/****************************************************************************
* Name: ramlog_copybuf
****************************************************************************/
static void ramlog_copybuf(FAR struct ramlog_dev_s *priv,
FAR const char *buffer, size_t len)
{
FAR struct ramlog_header_s *header = priv->rl_header;
FAR char *buf = header->rl_buffer;
uint32_t offset;
uint32_t tail;
if (len <= 0)
{
return;
}
offset = header->rl_head % priv->rl_bufsize;
tail = priv->rl_bufsize - offset;
if (len > tail)
{
memcpy(&buf[offset], buffer, tail);
memcpy(buf, buffer + tail, len - tail);
}
else
{
memcpy(&buf[offset], buffer, len);
}
header->rl_head += len;
}
/****************************************************************************
* Name: ramlog_addbuf
****************************************************************************/
static ssize_t ramlog_addbuf(FAR struct ramlog_dev_s *priv,
FAR const char *buffer, size_t len)
{
#if defined(CONFIG_RAMLOG_SYSLOG) || defined(CONFIG_RAMLOG_CRLF)
FAR struct ramlog_header_s *header = priv->rl_header;
#endif
size_t buflen = len;
irqstate_t flags;
#ifdef CONFIG_RAMLOG_CRLF
FAR const char *end;
FAR const char *pos;
FAR char *buf;
#endif
/* Disable interrupts (in case we are NOT called from interrupt handler) */
flags = enter_critical_section();
#ifdef CONFIG_RAMLOG_SYSLOG
if (header->rl_magic != RAMLOG_MAGIC_NUMBER && priv == &g_sysdev)
{
memset(header, 0, sizeof(g_sysbuffer));
header->rl_magic = RAMLOG_MAGIC_NUMBER;
}
#endif
if (buflen > priv->rl_bufsize)
{
buffer += buflen - priv->rl_bufsize;
buflen = priv->rl_bufsize;
}
#ifdef CONFIG_RAMLOG_CRLF
buf = header->rl_buffer;
end = buffer + buflen;
pos = buffer;
do
{
/* Ignore carriage returns */
if (*pos == '\r' || *pos == '\n')
{
ramlog_copybuf(priv, buffer, pos - buffer);
buffer = pos + 1;
}
/* Pre-pend a carriage before a linefeed */
if (*pos == '\n')
{
buf[header->rl_head++ % priv->rl_bufsize] = '\r';
buf[header->rl_head++ % priv->rl_bufsize] = '\n';
}
}
while (++pos != end);
ramlog_copybuf(priv, buffer, pos - buffer);
#else
ramlog_copybuf(priv, buffer, buflen);
#endif
/* Was anything written? */
if (len > 0)
{
/* Lock the scheduler do NOT switch out */
if (!up_interrupt_context())
{
sched_lock();
}
#ifndef CONFIG_RAMLOG_NONBLOCKING
/* Are there threads waiting for read data? */
ramlog_readnotify(priv);
#endif
/* Notify all poll/select waiters that they can read from the FIFO */
ramlog_pollnotify(priv);
/* Unlock the scheduler */
if (!up_interrupt_context())
{
sched_unlock();
}
}
/* We always have to return the number of bytes requested and NOT the
* number of bytes that were actually written. Otherwise, callers
* probably retry, causing same error condition again.
*/
leave_critical_section(flags);
return len;
}
/****************************************************************************
* Name: ramlog_read
****************************************************************************/
static ssize_t ramlog_file_read(FAR struct file *filep, FAR char *buffer,
size_t len)
{
FAR struct inode *inode = filep->f_inode;
FAR struct ramlog_dev_s *priv = inode->i_private;
FAR struct ramlog_header_s *header = priv->rl_header;
FAR struct ramlog_user_s *upriv = filep->f_priv;
irqstate_t flags;
uint32_t ncopy;
ssize_t nread;
uint32_t tail;
uint32_t pos;
/* If the circular buffer is empty, then wait for something to be written
* to it. This function may NOT be called from an interrupt handler.
*/
DEBUGASSERT(!up_interrupt_context());
/* Get exclusive access to the rl_tail index */
flags = enter_critical_section();
/* Loop until something is read */
for (nread = 0; (size_t)nread < len; )
{
/* Get the next byte from the buffer */
if (header->rl_head == upriv->rl_tail)
{
/* The circular buffer is empty. */
#ifdef CONFIG_RAMLOG_NONBLOCKING
/* Return what we have (with zero mean the end-of-file) */
break;
#else
int ret;
/* Did we read anything? */
if (nread > 0)
{
/* Yes.. break out to return what we have. */
break;
}
/* If the driver was opened with O_NONBLOCK option, then don't
* wait.
*/
if (filep->f_oflags & O_NONBLOCK)
{
nread = -EAGAIN;
break;
}
/* We may now be pre-empted! But that should be okay because we
* have already incremented nwaiters. Pre-emptions is disabled
* but will be re-enabled while we are waiting.
*/
ret = nxsem_wait(&upriv->rl_waitsem);
/* Did we successfully get the rl_waitsem? */
if (ret < 0)
{
/* No.. nxsem_wait's failed. */
/* Return the error. We did handle the case where we read
* anything already before waiting.
*/
return ret;
}
#endif /* CONFIG_RAMLOG_NONBLOCKING */
}
else
{
/* Determine whether the read pointer is overwritten */
if (header->rl_head - upriv->rl_tail > priv->rl_bufsize)
{
upriv->rl_tail = header->rl_head - priv->rl_bufsize;
}
/* The circular buffer is not empty, get the next byte from the
* tail index.
*/
pos = upriv->rl_tail % priv->rl_bufsize;
ncopy = header->rl_head - upriv->rl_tail;
tail = priv->rl_bufsize - pos;
if (ncopy > len - nread)
{
ncopy = len - nread;
}
if (ncopy > tail)
{
memcpy(&buffer[nread], &header->rl_buffer[pos], tail);
memcpy(&buffer[nread + tail], header->rl_buffer, ncopy - tail);
}
else
{
memcpy(&buffer[nread], &header->rl_buffer[pos], ncopy);
}
upriv->rl_tail += ncopy;
nread += ncopy;
}
}
leave_critical_section(flags);
/* Return the number of characters actually read */
return nread;
}
/****************************************************************************
* Name: ramlog_file_write
****************************************************************************/
static ssize_t ramlog_file_write(FAR struct file *filep,
FAR const char *buffer, size_t len)
{
FAR struct inode *inode = filep->f_inode;
FAR struct ramlog_dev_s *priv = inode->i_private;
return ramlog_addbuf(priv, buffer, len);
}
/****************************************************************************
* Name: ramlog_file_ioctl
****************************************************************************/
static int ramlog_file_ioctl(FAR struct file *filep, int cmd,
unsigned long arg)
{
FAR struct inode *inode = filep->f_inode;
FAR struct ramlog_dev_s *priv = inode->i_private;
FAR struct ramlog_user_s *upriv = filep->f_priv;
irqstate_t flags;
int ret = 0;
flags = enter_critical_section();
switch (cmd)
{
case FIONREAD:
*(FAR int *)((uintptr_t)arg) = ramlog_bufferused(priv, upriv);
break;
case PIPEIOC_POLLINTHRD:
upriv->rl_threashold = (uint32_t)arg;
break;
case BIOC_FLUSH:
ramlog_bufferflush(priv);
break;
default:
ret = -ENOTTY;
break;
}
leave_critical_section(flags);
return ret;
}
/****************************************************************************
* Name: ramlog_file_poll
****************************************************************************/
static int ramlog_file_poll(FAR struct file *filep, FAR struct pollfd *fds,
bool setup)
{
FAR struct inode *inode = filep->f_inode;
FAR struct ramlog_dev_s *priv = inode->i_private;
FAR struct ramlog_user_s *upriv = filep->f_priv;
pollevent_t eventset = POLLOUT;
irqstate_t flags;
/* Get exclusive access to the poll structures */
flags = enter_critical_section();
/* Are we setting up the poll? Or tearing it down? */
if (setup)
{
/* This is a request to set up the poll. Find an available
* slot for the poll structure reference.
*/
if (!upriv->rl_fds)
{
upriv->rl_fds = fds;
fds->priv = &upriv->rl_fds;
}
/* Should immediately notify on any of the requested events? */
/* Check if the receive buffer is not empty. */
if (ramlog_bufferused(priv, upriv) >= upriv->rl_threashold)
{
eventset |= POLLIN;
}
poll_notify(&fds, 1, eventset);
}
else if (fds->priv)
{
/* This is a request to tear down the poll. */
FAR struct pollfd **slot = (FAR struct pollfd **)fds->priv;
/* Remove all memory of the poll setup */
*slot = NULL;
fds->priv = NULL;
}
leave_critical_section(flags);
return 0;
}
/****************************************************************************
* Name: ramlog_file_open
****************************************************************************/
static int ramlog_file_open(FAR struct file *filep)
{
FAR struct inode *inode = filep->f_inode;
FAR struct ramlog_dev_s *priv = inode->i_private;
FAR struct ramlog_header_s *header = priv->rl_header;
FAR struct ramlog_user_s *upriv;
irqstate_t flags;
/* Get exclusive access to the rl_tail index */
upriv = kmm_zalloc(sizeof(FAR struct ramlog_user_s));
if (upriv == NULL)
{
return -ENOMEM;
}
upriv->rl_threashold = CONFIG_RAMLOG_POLLTHRESHOLD;
#ifndef CONFIG_RAMLOG_NONBLOCKING
nxsem_init(&upriv->rl_waitsem, 0, 0);
#endif
flags = enter_critical_section();
list_add_tail(&priv->rl_list, &upriv->rl_node);
upriv->rl_tail = header->rl_head > priv->rl_bufsize ?
header->rl_head - priv->rl_bufsize : 0;
leave_critical_section(flags);
filep->f_priv = upriv;
return 0;
}
/****************************************************************************
* Name: ramlog_file_close
****************************************************************************/
static int ramlog_file_close(FAR struct file *filep)
{
FAR struct ramlog_user_s *upriv = filep->f_priv;
irqstate_t flags;
/* Get exclusive access to the rl_tail index */
flags = enter_critical_section();
list_delete(&upriv->rl_node);
leave_critical_section(flags);
#ifndef CONFIG_RAMLOG_NONBLOCKING
nxsem_destroy(&upriv->rl_waitsem);
#endif
kmm_free(upriv);
return 0;
}
/****************************************************************************
* Public Functions
****************************************************************************/
/****************************************************************************
* Name: ramlog_register
*
* Description:
* Create the RAM logging device and register it at the specified path.
*
****************************************************************************/
int ramlog_register(FAR const char *devpath, FAR char *buffer, size_t buflen)
{
FAR struct ramlog_dev_s *priv;
int ret = -ENOMEM;
/* Sanity checking */
DEBUGASSERT(devpath && buffer && buflen > sizeof(struct ramlog_header_s));
/* Allocate a RAM logging device structure */
priv = kmm_zalloc(sizeof(struct ramlog_dev_s));
if (priv != NULL)
{
/* Initialize the non-zero values in the RAM logging device structure */
list_initialize(&priv->rl_list);
priv->rl_bufsize = buflen - sizeof(struct ramlog_header_s);
priv->rl_header = (FAR struct ramlog_header_s *)buffer;
/* Register the character driver */
ret = register_driver(devpath, &g_ramlogfops, 0666, priv);
if (ret < 0)
{
kmm_free(priv);
}
}
return ret;
}
/****************************************************************************
* Name: ramlog_syslog_register
*
* Description:
* Use a pre-allocated RAM logging device and register it at the path
* specified by CONFIG_RAMLOG_SYSLOG
*
****************************************************************************/
#ifdef CONFIG_RAMLOG_SYSLOG
void ramlog_syslog_register(void)
{
/* Register the syslog character driver */
register_driver(CONFIG_SYSLOG_DEVPATH, &g_ramlogfops, 0666, &g_sysdev);
}
#endif
/****************************************************************************
* Name: ramlog_putc
*
* Description:
* This is the low-level system logging interface.
*
****************************************************************************/
#ifdef CONFIG_RAMLOG_SYSLOG
int ramlog_putc(FAR syslog_channel_t *channel, int ch)
{
char cch = ch;
UNUSED(channel);
/* Add the character to the RAMLOG */
ramlog_addbuf(&g_sysdev, &cch, 1);
/* Return the character added on success */
return ch;
}
ssize_t ramlog_write(FAR syslog_channel_t *channel,
FAR const char *buffer, size_t buflen)
{
return ramlog_addbuf(&g_sysdev, buffer, buflen);
}
#endif
#endif /* CONFIG_RAMLOG */
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