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PTY: Fix termios read input processing.. what was I thinking? Also, if some data was read, pty_read() should not block on the empty FIFO.

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This commit is contained in:
Gregory Nutt 2016-07-18 08:00:56 -06:00
parent e0aaa168aa
commit 6194467c13
2 changed files with 78 additions and 18 deletions
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3
drivers/pipes/pipe_common.c
View File

@ -397,7 +397,7 @@ int pipecommon_close(FAR struct file *filep)
return OK;
}
#endif
}
}
sem_post(&dev->d_bfsem);
return OK;
@ -475,6 +475,7 @@ ssize_t pipecommon_read(FAR struct file *filep, FAR char *buffer, size_t len)
{
dev->d_rdndx = 0;
}
nread++;
}

93
drivers/serial/pty.c
View File

@ -57,6 +57,14 @@
#include "pty.h"
/****************************************************************************
* Pre-processor Definitions
****************************************************************************/
/* Should never be set... only for comparison to serial.c */
#undef CONFIG_PSEUDOTERM_FULLBLOCKS
/****************************************************************************
* Private Function Prototypes
****************************************************************************/
@ -180,7 +188,9 @@ static void pty_destroy(FAR struct pty_devpair_s *devpair)
#endif
(void)unregister_driver(devname);
/* Un-register the master device (/dev/ptyN may have already been unlinked) */
/* Un-register the master device (/dev/ptyN may have already been
* unlinked).
*/
snprintf(devname, 16, "/dev/pty%d", (int)devpair->pp_minor);
(void)unregister_driver(devname);
@ -377,6 +387,7 @@ static ssize_t pty_read(FAR struct file *filep, FAR char *buffer, size_t len)
ssize_t nread;
size_t i;
char ch;
int ret;
#endif
DEBUGASSERT(filep != NULL && filep->f_inode != NULL);
@ -389,24 +400,71 @@ static ssize_t pty_read(FAR struct file *filep, FAR char *buffer, size_t len)
*
* Specifically not handled:
*
* All of the local modes; echo, line editing, etc.
* Anything to do with break or parity errors.
* ISTRIP - We should be 8-bit clean.
* IUCLC - Not Posix
* IXON/OXOFF - No xon/xoff flow control.
* All of the local modes; echo, line editing, etc.
* Anything to do with break or parity errors.
* ISTRIP - We should be 8-bit clean.
* IUCLC - Not Posix
* IXON/OXOFF - No xon/xoff flow control.
*/
if (dev->pd_iflag & (INLCR | IGNCR | ICRNL))
{
/* We will transfer one byte at a time, making the appropriae
/* We will transfer one byte at a time, making the appropriate
* translations.
*/
ntotal = 0;
for (i = 0; i < len; i++)
{
ch = *buffer++;
#ifndef CONFIG_PSEUDOTERM_FULLBLOCKS
/* This logic should return if the pipe becomes empty after some
* bytes were read from the pipe. If we have already read some
* data, we use the FIONREAD ioctl to test if there are more bytes
* in the pipe.
*
* There is an inherent race condition in this test, but leaving
* a few bytes unnecessarily in the pipe should not be harmful.
* (we could lock the scheduler between the test and the
* file_read() below if we wanted to eliminate the race)
*/
if (ntotal > 0)
{
int nsrc;
/* Check how many bytes are waiting in the pipe */
ret = file_ioctl(&dev->pd_src, FIONREAD,
(unsigned long)((uintptr_t)&nsrc));
if (ret < 0)
{
ntotal = ret;
break;
}
/* Break out of the loop and return ntotal if the pipe is
* empty.
*/
if (nsrc < 1)
{
break;
}
}
#endif
/* Read one byte from the source the byte. This call will block
* if the source pipe is empty.
*/
nread = file_read(&dev->pd_src, &ch, 1);
if (nread < 0)
{
ntotal = nread;
break;
}
/* Perform input processing */
/* \n -> \r or \r -> \n translation? */
if (ch == '\n' && (dev->pd_iflag & INLCR) != 0)
@ -424,17 +482,12 @@ static ssize_t pty_read(FAR struct file *filep, FAR char *buffer, size_t len)
if (ch != '\r' || (dev->pd_iflag & IGNCR) == 0)
{
/* Transfer the byte */
nread = file_read(&dev->pd_src, &ch, 1);
if (nread < 0)
{
ntotal = nread;
break;
}
/* Update the count of bytes transferred */
/* Transfer the (possibly translated) character and update the
* count of bytes transferred.
*/
*buffer++ = ch;
ntotal++;
}
}
@ -442,6 +495,12 @@ static ssize_t pty_read(FAR struct file *filep, FAR char *buffer, size_t len)
else
#endif
{
/* NOTE: the source pipe will block is no data is available in
* the pipe. Otherwise, it will return data from the pipe. If
* there are fewer than 'len' bytes in the, it will return with
* ntotal < len.
*/
ntotal = file_read(&dev->pd_src, buffer, len);
}