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The RAM log cannot block like more character drivers, otherwise cat /dev/syslog does not work 

git-svn-id: https://nuttx.svn.sourceforge.net/svnroot/nuttx/trunk@4383 7fd9a85b-ad96-42d3-883c-3090e2eb8679
This commit is contained in:
patacongo 2012-02-11 15:58:11 +00:00
parent 592c4f7deb
commit 57ae1bb526
2 changed files with 84 additions and 6 deletions
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77
nuttx/drivers/ramlog.c
View File

@ -72,11 +72,15 @@
struct ramlog_dev_s
{
#ifndef CONFIG_RAMLOG_NONBLOCKING
volatile uint8_t rl_nwaiters; /* Number of threads waiting for data */
#endif
volatile uint16_t rl_head; /* The head index (where data is added) */
volatile uint16_t rl_tail; /* The tail index (where data is removed) */
sem_t rl_exclsem; /* Enforces mutually exclusive access */
#ifndef CONFIG_RAMLOG_NONBLOCKING
sem_t rl_waitsem; /* Used to wait for data */
#endif
size_t rl_bufsize; /* Size of the RAM buffer */
FAR char *rl_buffer; /* Circular RAM buffer */
@ -252,7 +256,14 @@ static ssize_t ramlog_read(FAR struct file *filep, FAR char *buffer, size_t len)
if (priv->rl_head == priv->rl_tail)
{
/* The circular buffer is empty. Did we read anything? */
/* The circular buffer is empty. */
#ifdef CONFIG_RAMLOG_NONBLOCKING
/* Return what we have (with zero mean the end-of-file) */
break;
#else
/* Did we read anything? */
if (nread > 0)
{
@ -333,6 +344,7 @@ static ssize_t ramlog_read(FAR struct file *filep, FAR char *buffer, size_t len)
goto errout_without_sem;
}
#endif /* CONFIG_RAMLOG_NONBLOCKING */
}
else
{
@ -362,7 +374,10 @@ static ssize_t ramlog_read(FAR struct file *filep, FAR char *buffer, size_t len)
/* Notify all poll/select waiters that they can write to the FIFO */
#ifndef CONFIG_RAMLOG_NONBLOCKING
errout_without_sem:
#endif
#ifndef CONFIG_DISABLE_POLL
if (nread > 0)
{
@ -380,9 +395,9 @@ static ssize_t ramlog_write(FAR struct file *filep, FAR const char *buffer, size
{
struct inode *inode = filep->f_inode;
struct ramlog_dev_s *priv;
irqstate_t flags;
ssize_t nwritten;
int i;
char ch;
int ret;
/* Some sanity checking */
@ -400,7 +415,29 @@ static ssize_t ramlog_write(FAR struct file *filep, FAR const char *buffer, size
for (nwritten = 0; nwritten < len; nwritten++)
{
int ret = ramlog_addchar(priv, buffer[nwritten]);
/* Get the next character to output */
ch = buffer[nwritten];
/* Pre-pend a carriage before a linefeed */
if (ch == '\n')
{
ret = ramlog_addchar(priv, '\r');
if (ret < 0)
{
/* The buffer is full and nothing was saved. Break out of the
* loop to return the number of bytes written up to this point.
* The data to be written is dropped on the floor.
*/
break;
}
}
/* Then output the character */
ret = ramlog_addchar(priv,ch);
if (ret < 0)
{
/* The buffer is full and nothing was saved. Break out of the
@ -414,23 +451,29 @@ static ssize_t ramlog_write(FAR struct file *filep, FAR const char *buffer, size
/* Was anything written? */
#if !defined(CONFIG_RAMLOG_NONBLOCKING) || !defined(CONFIG_DISABLE_POLL)
if (nwritten > 0)
{
int i;
/* Are there threads waiting for read data? */
flags = irqsave();
irqstate_t flags = irqsave();
#ifndef CONFIG_RAMLOG_NONBLOCKING
for (i = 0; i < priv->rl_nwaiters; i++)
{
/* Yes.. Notify all of the waiting readers that more data is available */
sem_post(&priv->rl_waitsem);
}
#endif
/* Notify all poll/select waiters that they can write to the FIFO */
ramlog_pollnotify(priv, POLLIN);
irqrestore(flags);
}
#endif
/* Return the number of bytes written */
@ -581,7 +624,9 @@ int ramlog_register(FAR const char *devpath, FAR char *buffer, size_t buflen)
/* Initialize the non-zero values in the RAM logging device structure */
sem_init(&priv->rl_exclsem, 0, 1);
#ifndef CONFIG_RAMLOG_NONBLOCKING
sem_init(&priv->rl_waitsem, 0, 0);
#endif
priv->rl_bufsize = buflen;
priv->rl_buffer = buffer;
@ -616,7 +661,9 @@ int ramlog_consoleinit(void)
/* Initialize the RAM loggin device structure */
sem_init(&priv->rl_exclsem, 0, 1);
#ifndef CONFIG_RAMLOG_NONBLOCKING
sem_init(&priv->rl_waitsem, 0, 0);
#endif
priv->rl_bufsize = CONFIG_RAMLOG_CONSOLE_BUFSIZE;
priv->rl_buffer = g_sysbuffer;
@ -656,7 +703,9 @@ int ramlog_sysloginit(void)
/* Initialize the RAM loggin device structure */
sem_init(&priv->rl_exclsem, 0, 1);
#ifndef CONFIG_RAMLOG_NONBLOCKING
sem_init(&priv->rl_waitsem, 0, 0);
#endif
priv->rl_bufsize = CONFIG_RAMLOG_CONSOLE_BUFSIZE;
priv->rl_buffer = g_sysbuffer;
@ -681,6 +730,24 @@ int ramlog_sysloginit(void)
int ramlog_putc(int ch)
{
FAR struct ramlog_dev_s *priv = &g_sysdev;
int ret;
/* Pre-pend a newline with a carriage return */
if (ch == '\n')
{
ret = ramlog_addchar(priv, '\r');
if (ret < 0)
{
/* The buffer is full and nothing was saved. Break out of the
* loop to return the number of bytes written up to this point.
* The data to be written is dropped on the floor.
*/
return ch;
}
}
(void)ramlog_addchar(priv, ch);
return ch;
}

11
nuttx/include/nuttx/ramlog.h
View File

@ -102,6 +102,17 @@
# define CONFIG_RAMLOG_CONSOLE_BUFSIZE 1024
#endif
/* The normal behavior of the RAM log when used as a SYSLOG is to return
* end-of-file if there is no data in the RAM log (rather than blocking until
* data is available). That allows you to cat the SYSLOG with no ill
* consequences.
*/
#ifdef CONFIG_SYSLOG
# undef CONFIG_RAMLOG_NONBLOCKING
# define CONFIG_RAMLOG_NONBLOCKING 1
#endif
/****************************************************************************
* Public Data
****************************************************************************/