#include <lttng/lttng-kconsumer.h>
#include <lttngerr.h>
+#include "common/runas.h"
+
extern struct lttng_consumer_global_data consumer_data;
extern int consumer_poll_timeout;
extern volatile int consumer_quit;
msg.u.stream.state,
msg.u.stream.mmap_len,
msg.u.stream.output,
- msg.u.stream.path_name);
+ msg.u.stream.path_name,
+ msg.u.stream.uid,
+ msg.u.stream.gid);
if (new_stream == NULL) {
lttng_consumer_send_error(ctx, CONSUMERD_OUTFD_ERROR);
goto end;
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,
+ struct lttng_consumer_local_data *ctx)
+{
+ unsigned long len;
+ int err;
+ long 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,
+ * so get_subbuf may fail for short race windows where poll()
+ * would issue wakeups.
+ */
+ DBG("Reserving sub buffer failed (everything is normal, "
+ "it is due to concurrency)");
+ goto end;
+ }
+
+ switch (stream->output) {
+ case LTTNG_EVENT_SPLICE:
+ /* read the whole subbuffer */
+ err = kernctl_get_padded_subbuf_size(infd, &len);
+ if (err != 0) {
+ ret = errno;
+ 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) {
+ /*
+ * 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;
+ 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) {
+ /*
+ * display the error but continue processing to try
+ * to release the subbuffer
+ */
+ ERR("Error writing to tracefile");
+ }
+ break;
+ default:
+ ERR("Unknown output method");
+ ret = -1;
+ }
+
+ err = kernctl_put_next_subbuf(infd);
+ if (err != 0) {
+ ret = errno;
+ if (errno == EFAULT) {
+ perror("Error in unreserving sub buffer\n");
+ } else if (errno == EIO) {
+ /* Should never happen with newer LTTng versions */
+ perror("Reader has been pushed by the writer, last sub-buffer corrupted.");
+ }
+ goto end;
+ }
+
+end:
+ return ret;
+}
+
+int lttng_kconsumer_on_recv_stream(struct lttng_consumer_stream *stream)
+{
+ int ret;
+
+ /* Opening the tracefile in write mode */
+ if (stream->path_name != NULL) {
+ ret = open_run_as(stream->path_name,
+ O_WRONLY|O_CREAT|O_TRUNC,
+ S_IRWXU|S_IRWXG|S_IRWXO,
+ stream->uid, stream->gid);
+ if (ret < 0) {
+ ERR("Opening %s", stream->path_name);
+ perror("open");
+ goto error;
+ }
+ stream->out_fd = ret;
+ }
+
+ if (stream->output == LTTNG_EVENT_MMAP) {
+ /* get the len of the mmap region */
+ unsigned long mmap_len;
+
+ ret = kernctl_get_mmap_len(stream->wait_fd, &mmap_len);
+ if (ret != 0) {
+ ret = errno;
+ perror("kernctl_get_mmap_len");
+ goto error_close_fd;
+ }
+ stream->mmap_len = (size_t) mmap_len;
+
+ stream->mmap_base = mmap(NULL, stream->mmap_len,
+ PROT_READ, MAP_PRIVATE, stream->wait_fd, 0);
+ if (stream->mmap_base == MAP_FAILED) {
+ perror("Error mmaping");
+ ret = -1;
+ goto error_close_fd;
+ }
+ }
+
+ /* we return 0 to let the library handle the FD internally */
+ return 0;
+
+error_close_fd:
+ {
+ int err;
+
+ err = close(stream->out_fd);
+ assert(!err);
+ }
+error:
+ return ret;
+}
+
projects / lttng-tools.git / blobdiff