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Fix FIFO interlock errors

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git-svn-id: svn://svn.code.sf.net/p/nuttx/code/trunk@784 42af7a65-404d-4744-a932-0658087f49c3
This commit is contained in:
patacongo 2008-07-26 20:40:49 +00:00
parent e2f289a52c
commit 33e6d3e45d
4 changed files with 197 additions and 51 deletions
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1
ChangeLog
View File

@ -377,4 +377,5 @@
* Add mkfifo()
* Add pipe() and test for both pipes and fifos
* Attempts to open a FIFO will now block until there is at least one writer
* Add test/Fixed errors in FIFO reader/writer interlocks

1
Documentation/NuttX.html
View File

@ -1026,6 +1026,7 @@ nuttx-0.3.12 2008-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr>
* Add mkfifo()
* Add pipe() and test for both pipes and fifos
* Attempts to open a FIFO will now block until there is at least one writer
* Add test/Fixed errors in FIFO reader/writer interlocks
pascal-0.1.3 2008-xx-xx Gregory Nutt <spudmonkey@racsa.co.cr>

12
drivers/pipe-common.c
View File

@ -178,7 +178,7 @@ int pipecommon_open(FAR struct file *filep)
sched_lock();
(void)sem_post(&dev->s.d_bfsem);
if ((filep->f_oflags & O_RDWR) != O_RDONLY && dev->s.d_nwriters < 1)
if ((filep->f_oflags & O_RDWR) == O_RDONLY && dev->s.d_nwriters < 1)
{
/* NOTE: d_rdsem is normally used when the read logic waits for more
* data to be written. But until the first writer has opened the
@ -245,19 +245,9 @@ int pipecommon_close(FAR struct file *filep)
}
}
}
sem_post(&dev->s.d_bfsem);
}
else
{
/* Then nothing else can be holding the semaphore, so it is save to */
inode->i_private = NULL;
sem_post(&dev->s.d_bfsem);
/* Then free the pipe structure instance */
pipecommon_freedev(dev);
}
return OK;
}

230
examples/pipe/pipe_main.c
View File

@ -52,9 +52,8 @@
* Definitions
****************************************************************************/
#ifndef CONFIG_EXAMPLES_FIFO_PATH
# define CONFIG_EXAMPLES_FIFO_PATH "/tmp/testfifo"
#endif
#define FIFO_PATH1 "/tmp/testfifo-1"
#define FIFO_PATH2 "/tmp/testfifo-2"
#define MAX_BYTE 13
@ -170,10 +169,10 @@ static void *writer(pthread_addr_t pvarg)
}
/****************************************************************************
* Name: perform_test
* Name: transfer_test
****************************************************************************/
static int perform_test(int fdin, int fdout)
static int transfer_test(int fdin, int fdout)
{
pthread_t readerid;
pthread_t writerid;
@ -183,62 +182,208 @@ static int perform_test(int fdin, int fdout)
/* Start reader thread */
printf("perform_test: Starting reader thread\n");
printf("transfer_test: Starting reader thread\n");
ret = pthread_create(&readerid, NULL, reader, (pthread_addr_t)fdin);
if (ret != 0)
{
fprintf(stderr, "perform_test: Failed to create reader thread, error=%d\n", ret);
return -1;
fprintf(stderr, "transfer_test: Failed to create reader thread, error=%d\n", ret);
return 1;
}
/* Start writer thread */
printf("perform_test: Starting writer thread\n");
printf("transfer_test: Starting writer thread\n");
ret = pthread_create(&writerid, NULL, writer, (pthread_addr_t)fdout);
if (ret != 0)
{
fprintf(stderr, "perform_test: Failed to create writer thread, error=%d\n", ret);
fprintf(stderr, "transfer_test: Failed to create writer thread, error=%d\n", ret);
pthread_detach(readerid);
ret = pthread_cancel(readerid);
if (ret != 0)
{
fprintf(stderr, "perform_test: Failed to cancel reader thread, error=%d\n", ret);
fprintf(stderr, "transfer_test: Failed to cancel reader thread, error=%d\n", ret);
}
return -1;
return 2;
}
/* Wait for writer thread to complete */
printf("perform_test: Waiting for writer thread\n");
printf("transfer_test: Waiting for writer thread\n");
ret = pthread_join(writerid, &value);
if (ret != 0)
{
fprintf(stderr, "perform_test: pthread_join failed, error=%d\n", ret);
fprintf(stderr, "transfer_test: pthread_join failed, error=%d\n", ret);
}
else
{
ret = (int)value;
printf("perform_test: writer returned %d\n", ret);
printf("transfer_test: writer returned %d\n", ret);
}
/* Wait for reader thread to complete */
printf("perform_test: Waiting for reader thread\n");
printf("transfer_test: Waiting for reader thread\n");
tmp = pthread_join(readerid, &value);
if (tmp != 0)
{
fprintf(stderr, "perform_test: pthread_join failed, error=%d\n", ret);
fprintf(stderr, "transfer_test: pthread_join failed, error=%d\n", ret);
}
else
{
tmp = (int)value;
printf("perform_test: reader returned %d\n", tmp);
printf("transfer_test: reader returned %d\n", tmp);
}
if (ret == 0)
{
ret = tmp;
}
printf("perform_test: returning %d\n", ret);
printf("transfer_test: returning %d\n", ret);
return ret;
}
/****************************************************************************
* Name: null_writer
****************************************************************************/
static void *null_writer(pthread_addr_t pvarg)
{
int fd;
/* Wait a bit */
printf("null_writer: started -- sleeping\n");
sleep(5);
/* Then open the FIFO for write access */
printf("null_writer: Opening FIFO for write access\n");
fd = open(FIFO_PATH2, O_WRONLY);
if (fd < 0)
{
fprintf(stderr, "null_writer: Failed to open FIFO %s for writing, errno=%d\n",
FIFO_PATH2, errno);
return (void*)1;
}
/* Wait a bit more */
printf("null_writer: Opened %s for writing -- sleeping\n", FIFO_PATH2);
sleep(5);
/* Then close the FIFO */
printf("null_writer: Closing %s\n", FIFO_PATH2);
close(fd);
sleep(5);
printf("null_writer: Returning success\n");
return (void*)0;
}
/****************************************************************************
* Name: interlock_test
****************************************************************************/
static int interlock_test(void)
{
pthread_t writerid;
void *value;
char data[16];
ssize_t nbytes;
int fd;
int ret;
/* Create a FIFO */
ret = mkfifo(FIFO_PATH2, 0666);
if (ret < 0)
{
fprintf(stderr, "interlock_test: mkfifo failed with errno=%d\n", errno);
return 1;
}
/* Start the null_writer_thread */
printf("interlock_test: Starting null_writer thread\n");
ret = pthread_create(&writerid, NULL, null_writer, (pthread_addr_t)NULL);
if (ret != 0)
{
fprintf(stderr, "interlock_test: Failed to create null_writer thread, error=%d\n", ret);
ret = 2;
goto errout_with_fifo;
}
/* Open one end of the FIFO for reading. This open call should block until the
* null_writer thread opens the other end of the FIFO for writing.
*/
printf("interlock_test: Opening FIFO for read access\n");
fd = open(FIFO_PATH2, O_RDONLY);
if (fd < 0)
{
fprintf(stderr, "interlock_test: Failed to open FIFO %s for reading, errno=%d\n",
FIFO_PATH2, errno);
ret = 3;
goto errout_with_thread;
}
/* Attempt to read one byte from the FIFO. This should return end-of-file because
* the null_writer closes the FIFO without writing anything.
*/
printf("interlock_test: Reading from %s\n", FIFO_PATH2);
nbytes = read(fd, data, 16);
if (nbytes < 0 )
{
fprintf(stderr, "interlock_test: read failed, errno=%d\n", errno);
ret = 4;
goto errout_with_file;
}
else if (ret != 0)
{
fprintf(stderr, "interlock_test: Read %d bytes of data -- aborting: %d\n", nbytes);
ret = 5;
goto errout_with_file;
}
/* Close the file */
printf("interlock_test: Closing %s\n", FIFO_PATH2);
close(fd);
/* Wait for null_writer thread to complete */
printf("interlock_test: Waiting for null_writer thread\n");
ret = pthread_join(writerid, &value);
if (ret != 0)
{
fprintf(stderr, "interlock_test: pthread_join failed, error=%d\n", ret);
ret = 6;
goto errout_with_fifo;
}
else
{
printf("interlock_test: writer returned %d\n", (int)value);
if (value != (void*)0)
{
ret = 7;
goto errout_with_fifo;
}
}
/* unlink(FIFO_PATH2); */
printf("interlock_test: Returning success\n");
return 0;
errout_with_file:
close(fd);
errout_with_thread:
pthread_detach(writerid);
pthread_cancel(writerid);
errout_with_fifo:
/* unlink(FIFO_PATH2); */
printf("interlock_test: Returning %d\n", ret);
return ret;
}
@ -266,44 +411,45 @@ int user_start(int argc, char *argv[])
/* Test FIFO logic */
printf("user_start: Performing FIFO test\n");
ret = mkfifo(CONFIG_EXAMPLES_FIFO_PATH, 0666);
ret = mkfifo(FIFO_PATH1, 0666);
if (ret < 0)
{
fprintf(stderr, "user_start: mkfifo failed with errno=%d\n", errno);
return 1;
}
/* Open open end of the FIFO for reading and the other end for writing. NOTE:
* the following would not work on most FIFO implementations because the attempt
* to open just one end of the FIFO would block. The NuttX FIFOs do not block.
/* Open one end of the FIFO for reading and the other end for writing. NOTE:
* the following might not work on most FIFO implementations because the attempt
* to open just one end of the FIFO for writing might block. The NuttX FIFOs block
* only on open for read-only (see interlock_test()).
*/
filedes[1] = open(CONFIG_EXAMPLES_FIFO_PATH, O_WRONLY);
filedes[1] = open(FIFO_PATH1, O_WRONLY);
if (filedes[1] < 0)
{
fprintf(stderr, "user_start: Failed to open FIFO %s for writing, errno=%d\n",
CONFIG_EXAMPLES_FIFO_PATH, errno);
close(filedes[0]);
return 3;
FIFO_PATH1, errno);
return 2;
}
filedes[0] = open(CONFIG_EXAMPLES_FIFO_PATH, O_RDONLY);
filedes[0] = open(FIFO_PATH1, O_RDONLY);
if (filedes[0] < 0)
{
fprintf(stderr, "user_start: Failed to open FIFO %s for reading, errno=%d\n",
CONFIG_EXAMPLES_FIFO_PATH, errno);
return 2;
FIFO_PATH1, errno);
close(filedes[1]);
return 3;
}
/* Then perform the test using those file descriptors */
ret = perform_test(filedes[0], filedes[1]);
ret = transfer_test(filedes[0], filedes[1]);
close(filedes[0]);
close(filedes[1]);
unlink(CONFIG_EXAMPLES_FIFO_PATH);
/* unlink(FIFO_PATH1); fails */
if (ret != 0)
{
fprintf(stderr, "user_start: FIFO test FAILED\n");
fprintf(stderr, "user_start: FIFO test FAILED (%d)\n", ret);
return 4;
}
printf("user_start: FIFO test PASSED\n");
@ -315,22 +461,30 @@ int user_start(int argc, char *argv[])
if (ret < 0)
{
fprintf(stderr, "user_start: pipe failed with errno=%d\n", errno);
return 1;
return 5;
}
/* Then perform the test using those file descriptors */
ret = perform_test(filedes[0], filedes[1]);
ret = transfer_test(filedes[0], filedes[1]);
close(filedes[0]);
close(filedes[1]);
unlink(CONFIG_EXAMPLES_FIFO_PATH);
/* unlink(FIFO_PATH1); fails */
if (ret != 0)
{
fprintf(stderr, "user_start: PIPE test FAILED\n");
return 4;
fprintf(stderr, "user_start: PIPE test FAILED (%d)\n", ret);
return 6;
}
printf("user_start: PIPE test PASSED\n");
/* Then perform the FIFO interlock test */
ret = interlock_test();
if (ret != 0)
{
fprintf(stderr, "user_start: FIFO interlock test FAILED (%d)\n", ret);
return 7;
}
fflush(stdout);
return 0;
}