X-Git-Url: https://git.lttng.org/?p=lttng-tools.git;a=blobdiff_plain;f=src%2Fcommon%2Fkernel-consumer%2Fkernel-consumer.c;h=3c9687306dc2aa2e904ef35f9954bdcc37e1d436;hp=2054a865f75d76e78b19ec6b6d2e84718271eae1;hb=47e81c0236926bdee0423bf3f1e6ad3f1facc364;hpb=f5204c9440be52e1b17bbb2c82450277ec02a583 diff --git a/src/common/kernel-consumer/kernel-consumer.c b/src/common/kernel-consumer/kernel-consumer.c index 2054a865f..3c9687306 100644 --- a/src/common/kernel-consumer/kernel-consumer.c +++ b/src/common/kernel-consumer/kernel-consumer.c @@ -2,24 +2,22 @@ * 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 #include -#include #include #include #include @@ -28,10 +26,12 @@ #include #include #include +#include #include #include #include +#include #include "kernel-consumer.h" @@ -49,7 +49,7 @@ ssize_t lttng_kconsumer_on_read_subbuffer_mmap( struct lttng_consumer_stream *stream, unsigned long len) { unsigned long mmap_offset; - ssize_t 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; @@ -59,30 +59,40 @@ ssize_t lttng_kconsumer_on_read_subbuffer_mmap( if (ret != 0) { 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) { - errno = -ret; + 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 */ - sync_file_range(outfd, stream->out_fd_offset, 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); - - goto end; - end: - return ret; + return written; } /* @@ -94,7 +104,7 @@ ssize_t lttng_kconsumer_on_read_subbuffer_splice( struct lttng_consumer_local_data *ctx, struct lttng_consumer_stream *stream, unsigned long len) { - ssize_t 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; @@ -105,26 +115,40 @@ ssize_t lttng_kconsumer_on_read_subbuffer_splice( (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) { - errno = -ret; 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) { - errno = -ret; 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; /* This won't block, but will start writeout asynchronously */ - sync_file_range(outfd, stream->out_fd_offset, 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); @@ -132,7 +156,7 @@ ssize_t lttng_kconsumer_on_read_subbuffer_splice( splice_error: /* send the appropriate error description to sessiond */ - switch(ret) { + switch (ret) { case EBADF: lttng_consumer_send_error(ctx, CONSUMERD_SPLICE_EBADF); break; @@ -148,7 +172,7 @@ splice_error: } end: - return ret; + return written; } /* @@ -295,11 +319,20 @@ int lttng_kconsumer_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; } @@ -342,13 +375,14 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream, /* 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 */ @@ -360,7 +394,7 @@ ssize_t lttng_kconsumer_read_subbuffer(struct lttng_consumer_stream *stream, } /* 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