X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fust-consumer%2Fust-consumer.c;h=47c0d460ffb60cc612d9806325602c6eac459023;hp=e81f05041249a164ce09151e9907c0602b41d6be;hb=47e81c0236926bdee0423bf3f1e6ad3f1facc364;hpb=fbb2c21aac1386b7752f6254b2bd0bf001fa0ac1 diff --git a/src/common/ust-consumer/ust-consumer.c b/src/common/ust-consumer/ust-consumer.c index e81f05041..47c0d460f 100644 --- a/src/common/ust-consumer/ust-consumer.c +++ b/src/common/ust-consumer/ust-consumer.c @@ -2,19 +2,18 @@ * Copyright (C) 2011 - Julien Desfossez * Mathieu Desnoyers * - * 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 @@ -43,14 +42,14 @@ extern volatile int consumer_quit; /* * 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; @@ -58,31 +57,41 @@ int lttng_ustconsumer_on_read_subbuffer_mmap( 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; } /* @@ -90,7 +99,7 @@ end: * * 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) { @@ -109,8 +118,8 @@ int lttng_ustconsumer_take_snapshot(struct lttng_consumer_local_data *ctx, 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; @@ -131,8 +140,8 @@ int lttng_ustconsumer_get_produced_snapshot( 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; @@ -258,11 +267,20 @@ int lttng_ustconsumer_recv_cmd(struct lttng_consumer_local_data *ctx, 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; } @@ -347,7 +365,7 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream, 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; @@ -376,7 +394,7 @@ int lttng_ustconsumer_read_subbuffer(struct lttng_consumer_stream *stream, 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 @@ -401,7 +419,7 @@ int lttng_ustconsumer_on_recv_stream(struct lttng_consumer_stream *stream) stream->uid, stream->gid); if (ret < 0) { ERR("Opening %s", stream->path_name); - perror("open"); + PERROR("open"); goto error; } stream->out_fd = ret;