* 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
*
* Returns the number of bytes written
*/
-int lttng_kconsumer_on_read_subbuffer_mmap(
+ssize_t lttng_kconsumer_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;
+ ssize_t ret = 0, written = 0;
off_t orig_offset = stream->out_fd_offset;
int fd = stream->wait_fd;
int outfd = stream->out_fd;
/* get the offset inside the fd to mmap */
ret = kernctl_get_mmap_read_offset(fd, &mmap_offset);
if (ret != 0) {
- ret = -errno;
+ errno = -ret;
perror("kernctl_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;
+ 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_kconsumer_on_read_subbuffer_splice(
+ssize_t lttng_kconsumer_on_read_subbuffer_splice(
struct lttng_consumer_local_data *ctx,
struct lttng_consumer_stream *stream, unsigned long len)
{
- long ret = 0;
+ ssize_t ret = 0, written = 0;
loff_t offset = 0;
off_t orig_offset = stream->out_fd_offset;
int fd = stream->wait_fd;
(unsigned long)offset, fd);
ret = splice(fd, &offset, ctx->consumer_thread_pipe[1], NULL, len,
SPLICE_F_MOVE | SPLICE_F_MORE);
- DBG("splice chan to pipe ret %ld", ret);
+ DBG("splice chan to pipe ret %zd", ret);
if (ret < 0) {
- ret = errno;
perror("Error in relay splice");
+ if (written == 0) {
+ written = ret;
+ }
+ ret = errno;
goto splice_error;
}
ret = splice(ctx->consumer_thread_pipe[0], NULL, outfd, NULL, ret,
SPLICE_F_MOVE | SPLICE_F_MORE);
- DBG("splice pipe to file %ld", ret);
+ DBG("splice pipe to file %zd", ret);
if (ret < 0) {
- ret = errno;
perror("Error in file splice");
+ if (written == 0) {
+ written = ret;
+ }
+ ret = errno;
+ goto splice_error;
+ }
+ if (ret > len) {
+ errno = EINVAL;
+ perror("Wrote more data than requested");
+ written += ret;
+ ret = errno;
goto splice_error;
}
len -= ret;
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);
splice_error:
/* send the appropriate error description to sessiond */
- switch(ret) {
+ switch (ret) {
case EBADF:
lttng_consumer_send_error(ctx, CONSUMERD_SPLICE_EBADF);
break;
}
end:
- return ret;
+ return written;
}
/*
ret = kernctl_snapshot(infd);
if (ret != 0) {
- ret = errno;
+ errno = -ret;
perror("Getting sub-buffer snapshot.");
}
ret = kernctl_snapshot_get_produced(infd, pos);
if (ret != 0) {
- ret = errno;
+ errno = -ret;
perror("kernctl_snapshot_get_produced");
}
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;
}
/*
* Consume data on a file descriptor and write it on a trace file.
*/
-int lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
+ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream,
struct lttng_consumer_local_data *ctx)
{
unsigned long len;
int err;
- long ret = 0;
+ ssize_t ret = 0;
int infd = stream->wait_fd;
DBG("In read_subbuffer (infd : %d)", infd);
/* Get the next subbuffer */
err = kernctl_get_next_subbuf(infd);
if (err != 0) {
- ret = errno;
/*
* This is a debug message even for single-threaded consumer,
* because poll() have more relaxed criterions than get subbuf,
/* read the whole subbuffer */
err = kernctl_get_padded_subbuf_size(infd, &len);
if (err != 0) {
- ret = errno;
+ errno = -ret;
perror("Getting sub-buffer len failed.");
goto end;
}
/* splice the subbuffer to the tracefile */
ret = lttng_consumer_on_read_subbuffer_splice(ctx, stream, len);
- if (ret < 0) {
+ if (ret != len) {
/*
* display the error but continue processing to try
* to release the subbuffer
*/
ERR("Error splicing to tracefile");
}
+
break;
case LTTNG_EVENT_MMAP:
/* read the used subbuffer size */
err = kernctl_get_padded_subbuf_size(infd, &len);
if (err != 0) {
- ret = errno;
+ errno = -ret;
perror("Getting sub-buffer len failed.");
goto end;
}
/* 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
err = kernctl_put_next_subbuf(infd);
if (err != 0) {
- ret = errno;
+ errno = -ret;
if (errno == EFAULT) {
perror("Error in unreserving sub buffer\n");
} else if (errno == EIO) {
ret = kernctl_get_mmap_len(stream->wait_fd, &mmap_len);
if (ret != 0) {
- ret = errno;
+ errno = -ret;
perror("kernctl_get_mmap_len");
goto error_close_fd;
}
projects / lttng-tools.git / blobdiff