* Copyright (C) 2011 - Julien Desfossez <julien.desfossez@polymtl.ca>
* Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
*
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public License
- * as published by the Free Software Foundation; only version 2
- * of the License.
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License, version 2 only,
+ * as published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
#define _GNU_SOURCE
/*
* Mmap the ring buffer, read it and write the data to the tracefile.
*
- * Returns the number of bytes written
+ * Returns the number of bytes written, else negative value on error.
*/
-int lttng_ustconsumer_on_read_subbuffer_mmap(
+ssize_t lttng_ustconsumer_on_read_subbuffer_mmap(
struct lttng_consumer_local_data *ctx,
struct lttng_consumer_stream *stream, unsigned long len)
{
unsigned long mmap_offset;
- long ret = 0;
+ long ret = 0, written = 0;
off_t orig_offset = stream->out_fd_offset;
int outfd = stream->out_fd;
ret = ustctl_get_mmap_read_offset(stream->chan->handle,
stream->buf, &mmap_offset);
if (ret != 0) {
- ret = -errno;
- perror("ustctl_get_mmap_read_offset");
+ errno = -ret;
+ PERROR("ustctl_get_mmap_read_offset");
+ written = ret;
goto end;
}
while (len > 0) {
ret = write(outfd, stream->mmap_base + mmap_offset, len);
- if (ret >= len) {
- len = 0;
- } else if (ret < 0) {
- ret = -errno;
- perror("Error in file write");
+ if (ret < 0) {
+ if (errno == EINTR) {
+ /* restart the interrupted system call */
+ continue;
+ } else {
+ PERROR("Error in file write");
+ if (written == 0) {
+ written = ret;
+ }
+ goto end;
+ }
+ } else if (ret > len) {
+ PERROR("Error in file write");
+ written += ret;
goto end;
+ } else {
+ len -= ret;
+ mmap_offset += ret;
}
/* This won't block, but will start writeout asynchronously */
lttng_sync_file_range(outfd, stream->out_fd_offset, ret,
SYNC_FILE_RANGE_WRITE);
stream->out_fd_offset += ret;
+ written += ret;
}
-
lttng_consumer_sync_trace_file(stream, orig_offset);
-
- goto end;
-
end:
- return ret;
+ return written;
}
/*
*
* Returns the number of bytes spliced.
*/
-int lttng_ustconsumer_on_read_subbuffer_splice(
+ssize_t lttng_ustconsumer_on_read_subbuffer_splice(
struct lttng_consumer_local_data *ctx,
struct lttng_consumer_stream *stream, unsigned long len)
{
ret = ustctl_snapshot(stream->chan->handle, stream->buf);
if (ret != 0) {
- ret = errno;
- perror("Getting sub-buffer snapshot.");
+ errno = -ret;
+ PERROR("Getting sub-buffer snapshot.");
}
return ret;
ret = ustctl_snapshot_get_produced(stream->chan->handle,
stream->buf, pos);
if (ret != 0) {
- ret = errno;
- perror("kernctl_snapshot_get_produced");
+ errno = -ret;
+ PERROR("kernctl_snapshot_get_produced");
}
return ret;
break;
}
end:
- /* signal the poll thread */
- ret = write(ctx->consumer_poll_pipe[1], "4", 1);
- if (ret < 0) {
- perror("write consumer poll");
- }
+ /*
+ * Wake-up the other end by writing a null byte in the pipe
+ * (non-blocking). Important note: Because writing into the
+ * pipe is non-blocking (and therefore we allow dropping wakeup
+ * data, as long as there is wakeup data present in the pipe
+ * buffer to wake up the other end), the other end should
+ * perform the following sequence for waiting:
+ * 1) empty the pipe (reads).
+ * 2) perform update operation.
+ * 3) wait on the pipe (poll).
+ */
+ do {
+ ret = write(ctx->consumer_poll_pipe[1], "", 1);
+ } while (ret == -1UL && errno == EINTR);
end_nosignal:
return 0;
}
if (!stream->hangup_flush_done) {
do {
readlen = read(stream->wait_fd, &dummy, 1);
- } while (readlen == -1 && errno == -EINTR);
+ } while (readlen == -1 && errno == EINTR);
if (readlen == -1) {
ret = readlen;
goto end;
assert(err == 0);
/* write the subbuffer to the tracefile */
ret = lttng_consumer_on_read_subbuffer_mmap(ctx, stream, len);
- if (ret < 0) {
+ if (ret != len) {
/*
* display the error but continue processing to try
* to release the subbuffer
stream->uid, stream->gid);
if (ret < 0) {
ERR("Opening %s", stream->path_name);
- perror("open");
+ PERROR("open");
goto error;
}
stream->out_fd = ret;
projects / lttng-tools.git / blobdiff