RTOS/rtems
1
0
Fork 0
forked from Imagelibrary/rtems
Code Pull Requests Activity

PR2159: Have the FIFO driver read follow POSIX standard.

Browse Source 
The read call was only returning once the requested buffer was full.
The change returns any available data.
This commit is contained in:
Chris Johns
2013-12-10 12:33:22 +11:00
parent b51d8a4996
commit 9da8740f05
1 changed files with 40 additions and 42 deletions
Download Patch File Download Diff File Expand all files Collapse all files

82
cpukit/libfs/src/pipe/fifo.c
View File

@@ -390,54 +390,52 @@ ssize_t pipe_read(
if (! PIPE_LOCK(pipe))
return -EINTR;
while (read < count) {
while (PIPE_EMPTY(pipe)) {
/* Not an error */
if (pipe->Writers == 0)
goto out_locked;
while (PIPE_EMPTY(pipe)) {
/* Not an error */
if (pipe->Writers == 0)
goto out_locked;
if (LIBIO_NODELAY(iop)) {
ret = -EAGAIN;
goto out_locked;
}
/* Wait until pipe is no more empty or no writer exists */
pipe->waitingReaders ++;
PIPE_UNLOCK(pipe);
if (! PIPE_READWAIT(pipe))
ret = -EINTR;
if (! PIPE_LOCK(pipe)) {
/* WARN waitingReaders not restored! */
ret = -EINTR;
goto out_nolock;
}
pipe->waitingReaders --;
if (ret != 0)
goto out_locked;
if (LIBIO_NODELAY(iop)) {
ret = -EAGAIN;
goto out_locked;
}
/* Read chunk bytes */
chunk = MIN(count - read, pipe->Length);
chunk1 = pipe->Size - pipe->Start;
if (chunk > chunk1) {
memcpy(buffer + read, pipe->Buffer + pipe->Start, chunk1);
memcpy(buffer + read + chunk1, pipe->Buffer, chunk - chunk1);
/* Wait until pipe is no more empty or no writer exists */
pipe->waitingReaders ++;
PIPE_UNLOCK(pipe);
if (! PIPE_READWAIT(pipe))
ret = -EINTR;
if (! PIPE_LOCK(pipe)) {
/* WARN waitingReaders not restored! */
ret = -EINTR;
goto out_nolock;
}
else
memcpy(buffer + read, pipe->Buffer + pipe->Start, chunk);
pipe->Start += chunk;
pipe->Start %= pipe->Size;
pipe->Length -= chunk;
/* For buffering optimization */
if (PIPE_EMPTY(pipe))
pipe->Start = 0;
if (pipe->waitingWriters > 0)
PIPE_WAKEUPWRITERS(pipe);
read += chunk;
pipe->waitingReaders --;
if (ret != 0)
goto out_locked;
}
/* Read chunk bytes */
chunk = MIN(count - read, pipe->Length);
chunk1 = pipe->Size - pipe->Start;
if (chunk > chunk1) {
memcpy(buffer + read, pipe->Buffer + pipe->Start, chunk1);
memcpy(buffer + read + chunk1, pipe->Buffer, chunk - chunk1);
}
else
memcpy(buffer + read, pipe->Buffer + pipe->Start, chunk);
pipe->Start += chunk;
pipe->Start %= pipe->Size;
pipe->Length -= chunk;
/* For buffering optimization */
if (PIPE_EMPTY(pipe))
pipe->Start = 0;
if (pipe->waitingWriters > 0)
PIPE_WAKEUPWRITERS(pipe);
read += chunk;
out_locked:
PIPE_UNLOCK(pipe);