common: index and trace-chunk file creation/open API change

An API change to the common libraries is required for the following
functions to accomodate the clear feature:

- lttng_trace_chunk_open_file(),
- lttng_index_file_create_from_trace_chunk(),
- lttng_index_file_create_from_trace_chunk_read_only().

An "expect_no_file" boolean is introduced, allowing specific invocation
to consider a ENOENT errno as an expected condition (and not an error).
This is the case for instance for relayd live viewer_stream_rotate(),
which can fail to open files in the new chunk after a clear with per-pid
buffers. Same goes for viewer_get_next_index() and try_open_index().

Change the lttng_index_file_create_from_trace_chunk_read_only and
lttng_index_file_create_from_trace_chunk to allow them to return
a chunk status, which allows the callers to distinguish between
errors and a "no file" status, and deal with the situation accordingly.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Change-Id: I3c43edca01629488c4e777078db7ffd2e88dc7ea
Signed-off-by: Jérémie Galarneau <jeremie.galarneau@efficios.com>

diff --git a/src/bin/lttng-relayd/live.c b/src/bin/lttng-relayd/live.c
index 1b25671d5f76a82ad83a33ceceb3691e8794457c..250d85c6fb39fde7558004f95c198b216b009a6d 100644 (file)
--- a/src/bin/lttng-relayd/live.c
+++ b/src/bin/lttng-relayd/live.c
@@ -1222,6 +1222,7 @@ static int try_open_index(struct relay_viewer_stream *vstream,
        int ret = 0;
        const uint32_t connection_major = rstream->trace->session->major;
        const uint32_t connection_minor = rstream->trace->session->minor;
+       enum lttng_trace_chunk_status chunk_status;
 
        if (vstream->index_file) {
                goto end;
@@ -1234,14 +1235,19 @@ static int try_open_index(struct relay_viewer_stream *vstream,
                ret = -ENOENT;
                goto end;
        }
-       vstream->index_file = lttng_index_file_create_from_trace_chunk_read_only(
+       chunk_status = lttng_index_file_create_from_trace_chunk_read_only(
                        vstream->stream_file.trace_chunk, rstream->path_name,
                        rstream->channel_name, rstream->tracefile_size,
                        vstream->current_tracefile_id,
                        lttng_to_index_major(connection_major, connection_minor),
-                       lttng_to_index_minor(connection_major, connection_minor));
-       if (!vstream->index_file) {
-               ret = -1;
+                       lttng_to_index_minor(connection_major, connection_minor),
+                       true, &vstream->index_file);
+       if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+               if (chunk_status == LTTNG_TRACE_CHUNK_STATUS_NO_FILE) {
+                       ret = -ENOENT;
+               } else {
+                       ret = -1;
+               }
        }
 
 end:
@@ -1460,9 +1466,14 @@ int viewer_get_next_index(struct relay_connection *conn)
                        goto error_put;
                }
 
+               /*
+                * It is possible the the file we are trying to open is
+                * missing if the stream has been closed (application exits with
+                * per-pid buffers) and a clear command has been performed.
+                */
                status = lttng_trace_chunk_open_file(
                                vstream->stream_file.trace_chunk,
-                               file_path, O_RDONLY, 0, &fd);
+                               file_path, O_RDONLY, 0, &fd, true);
                if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
                        PERROR("Failed to open trace file for viewer stream");
                        goto error_put;
@@ -1759,9 +1770,14 @@ int viewer_get_metadata(struct relay_connection *conn)
                        goto error;
                }
 
+               /*
+                * It is possible the the metadata file we are trying to open is
+                * missing if the stream has been closed (application exits with
+                * per-pid buffers) and a clear command has been performed.
+                */
                status = lttng_trace_chunk_open_file(
                                vstream->stream_file.trace_chunk,
-                               file_path, O_RDONLY, 0, &fd);
+                               file_path, O_RDONLY, 0, &fd, true);
                if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
                        PERROR("Failed to open metadata file for viewer stream");
                        goto error;

diff --git a/src/bin/lttng-relayd/stream.c b/src/bin/lttng-relayd/stream.c
index d34158bd22dd0f1895f31419869979c356aee935..501e6e90a109615d09a562de1059aca894d64523 100644 (file)
--- a/src/bin/lttng-relayd/stream.c
+++ b/src/bin/lttng-relayd/stream.c
@@ -123,7 +123,7 @@ static int stream_create_data_output_file_from_trace_chunk(
        }
 
        status = lttng_trace_chunk_open_file(
-                       trace_chunk, stream_path, flags, mode, &fd);
+                       trace_chunk, stream_path, flags, mode, &fd, false);
        if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
                ERR("Failed to open stream file \"%s\"", stream->channel_name);
                ret = -1;
@@ -445,13 +445,14 @@ static int create_index_file(struct relay_stream *stream,
                ret = -1;
                goto end;
        }
-       stream->index_file = lttng_index_file_create_from_trace_chunk(
+       status = lttng_index_file_create_from_trace_chunk(
                        chunk, stream->path_name,
                        stream->channel_name, stream->tracefile_size,
                        stream->tracefile_current_index,
                        lttng_to_index_major(major, minor),
-                       lttng_to_index_minor(major, minor), true);
-       if (!stream->index_file) {
+                       lttng_to_index_minor(major, minor), true,
+                       &stream->index_file);
+       if (status != LTTNG_TRACE_CHUNK_STATUS_OK) {
                ret = -1;
                goto end;
        }

diff --git a/src/bin/lttng-relayd/viewer-stream.c b/src/bin/lttng-relayd/viewer-stream.c
index acd488b61846202813e8a7efe07898c1f67cfef7..70654c79710c19a17f9e3a30d3795156fbfed1f9 100644 (file)
--- a/src/bin/lttng-relayd/viewer-stream.c
+++ b/src/bin/lttng-relayd/viewer-stream.c
@@ -129,8 +129,9 @@ struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
        } else {
                const uint32_t connection_major = stream->trace->session->major;
                const uint32_t connection_minor = stream->trace->session->minor;
+               enum lttng_trace_chunk_status chunk_status;
 
-               vstream->index_file = lttng_index_file_create_from_trace_chunk_read_only(
+               chunk_status = lttng_index_file_create_from_trace_chunk_read_only(
                                vstream->stream_file.trace_chunk,
                                stream->path_name,
                                stream->channel_name, stream->tracefile_size,
@@ -138,9 +139,14 @@ struct relay_viewer_stream *viewer_stream_create(struct relay_stream *stream,
                                lttng_to_index_major(connection_major,
                                                connection_minor),
                                lttng_to_index_minor(connection_major,
-                                               connection_minor));
-               if (!vstream->index_file) {
-                       goto error_unlock;
+                                               connection_minor),
+                               true, &vstream->index_file);
+               if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
+                       if (chunk_status == LTTNG_TRACE_CHUNK_STATUS_NO_FILE) {
+                               vstream->index_file = NULL;
+                       } else {
+                               goto error_unlock;
+                       }
                }
        }
 
@@ -268,6 +274,7 @@ int viewer_stream_rotate(struct relay_viewer_stream *vstream)
        const struct relay_stream *stream = vstream->stream;
        const uint32_t connection_major = stream->trace->session->major;
        const uint32_t connection_minor = stream->trace->session->minor;
+       enum lttng_trace_chunk_status chunk_status;
 
        /* Detect the last tracefile to open. */
        if (stream->index_received_seqcount
@@ -316,8 +323,7 @@ int viewer_stream_rotate(struct relay_viewer_stream *vstream)
                stream_fd_put(vstream->stream_file.fd);
                vstream->stream_file.fd = NULL;
        }
-       vstream->index_file =
-                       lttng_index_file_create_from_trace_chunk_read_only(
+       chunk_status = lttng_index_file_create_from_trace_chunk_read_only(
                                        vstream->stream_file.trace_chunk,
                                        stream->path_name,
                                        stream->channel_name,
@@ -326,8 +332,9 @@ int viewer_stream_rotate(struct relay_viewer_stream *vstream)
                                        lttng_to_index_major(connection_major,
                                                        connection_minor),
                                        lttng_to_index_minor(connection_major,
-                                                       connection_minor));
-       if (!vstream->index_file) {
+                                                       connection_minor),
+                                       true, &vstream->index_file);
+       if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
                ret = -1;
                goto end;
        } else {

diff --git a/src/common/consumer/consumer-stream.c b/src/common/consumer/consumer-stream.c
index cdda9412ee8df2d97395a12abc3f2cdc52dd379d..daed3866fc639bae297089831721d500d7f185c7 100644 (file)
--- a/src/common/consumer/consumer-stream.c
+++ b/src/common/consumer/consumer-stream.c
@@ -594,7 +594,7 @@ int consumer_stream_create_output_files(struct lttng_consumer_stream *stream,
 
        DBG("Opening stream output file \"%s\"", stream_path);
        chunk_status = lttng_trace_chunk_open_file(stream->trace_chunk, stream_path,
-                       flags, mode, &stream->out_fd);
+                       flags, mode, &stream->out_fd, false);
         if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
                ERR("Failed to open stream file \"%s\"", stream->name);
                ret = -1;
@@ -605,15 +605,15 @@ int consumer_stream_create_output_files(struct lttng_consumer_stream *stream,
                if (stream->index_file) {
                        lttng_index_file_put(stream->index_file);
                }
-                stream->index_file = lttng_index_file_create_from_trace_chunk(
+               chunk_status = lttng_index_file_create_from_trace_chunk(
                                stream->trace_chunk,
                                stream->chan->pathname,
                                stream->name,
                                stream->chan->tracefile_size,
                                stream->tracefile_count_current,
                                CTF_INDEX_MAJOR, CTF_INDEX_MINOR,
-                               false);
-               if (!stream->index_file) {
+                               false, &stream->index_file);
+               if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
                        ret = -1;
                        goto end;
                }

diff --git a/src/common/index/index.c b/src/common/index/index.c
index 540294a5eae9f44e38328688e8f693567f8763b3..9f7e5f67a18dd4e8d67827890730695ec41bd2e2 100644 (file)
--- a/src/common/index/index.c
+++ b/src/common/index/index.c
@@ -34,13 +34,13 @@
 #define WRITE_FILE_FLAGS       (O_WRONLY | O_CREAT | O_TRUNC)
 #define READ_ONLY_FILE_FLAGS   O_RDONLY
 
-static struct lttng_index_file *_lttng_index_file_create_from_trace_chunk(
+static enum lttng_trace_chunk_status _lttng_index_file_create_from_trace_chunk(
                struct lttng_trace_chunk *chunk,
                const char *channel_path, const char *stream_name,
                uint64_t stream_file_size, uint64_t stream_file_index,
                uint32_t index_major, uint32_t index_minor,
                bool unlink_existing_file,
-               int flags)
+               int flags, bool expect_no_file, struct lttng_index_file **file)
 {
        struct lttng_index_file *index_file;
        enum lttng_trace_chunk_status chunk_status;
@@ -58,6 +58,7 @@ static struct lttng_index_file *_lttng_index_file_create_from_trace_chunk(
        index_file = zmalloc(sizeof(*index_file));
        if (!index_file) {
                PERROR("Failed to allocate lttng_index_file");
+               chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
                goto error;
        }
 
@@ -71,6 +72,7 @@ static struct lttng_index_file *_lttng_index_file_create_from_trace_chunk(
                        "%s%s" DEFAULT_INDEX_DIR, channel_path, separator);
        if (ret < 0 || ret >= sizeof(index_directory_path)) {
                ERR("Failed to format index directory path");
+               chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
                goto error;
        }
 
@@ -79,6 +81,7 @@ static struct lttng_index_file *_lttng_index_file_create_from_trace_chunk(
                        DEFAULT_INDEX_FILE_SUFFIX,
                        index_file_path, sizeof(index_file_path));
        if (ret) {
+               chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
                goto error;
        }
 
@@ -101,7 +104,7 @@ static struct lttng_index_file *_lttng_index_file_create_from_trace_chunk(
        }
 
        chunk_status = lttng_trace_chunk_open_file(chunk, index_file_path,
-                       flags, mode, &fd);
+                       flags, mode, &fd, expect_no_file);
        if (chunk_status != LTTNG_TRACE_CHUNK_STATUS_OK) {
                goto error;
        }
@@ -111,6 +114,7 @@ static struct lttng_index_file *_lttng_index_file_create_from_trace_chunk(
                size_ret = lttng_write(fd, &hdr, sizeof(hdr));
                if (size_ret < sizeof(hdr)) {
                        PERROR("Failed to write index header");
+                       chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
                        goto error;
                }
                index_file->element_len = ctf_packet_index_len(index_major, index_minor);
@@ -120,25 +124,30 @@ static struct lttng_index_file *_lttng_index_file_create_from_trace_chunk(
                size_ret = lttng_read(fd, &hdr, sizeof(hdr));
                if (size_ret < 0) {
                        PERROR("Failed to read index header");
+                       chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
                        goto error;
                }
                if (be32toh(hdr.magic) != CTF_INDEX_MAGIC) {
                        ERR("Invalid header magic");
+                       chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
                        goto error;
                }
                if (index_major != be32toh(hdr.index_major)) {
                        ERR("Index major number mismatch: %u, expect %u",
                                be32toh(hdr.index_major), index_major);
+                       chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
                        goto error;
                }
                if (index_minor != be32toh(hdr.index_minor)) {
                        ERR("Index minor number mismatch: %u, expect %u",
                                be32toh(hdr.index_minor), index_minor);
+                       chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
                        goto error;
                }
                element_len = be32toh(hdr.packet_index_len);
                if (element_len > sizeof(struct ctf_packet_index)) {
                        ERR("Index element length too long");
+                       chunk_status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
                        goto error;
                }
                index_file->element_len = element_len;
@@ -148,7 +157,8 @@ static struct lttng_index_file *_lttng_index_file_create_from_trace_chunk(
        index_file->minor = index_minor;
        urcu_ref_init(&index_file->ref);
 
-       return index_file;
+       *file = index_file;
+       return LTTNG_TRACE_CHUNK_STATUS_OK;
 
 error:
        if (fd >= 0) {
@@ -159,32 +169,33 @@ error:
        }
        lttng_trace_chunk_put(chunk);
        free(index_file);
-       return NULL;
+       return chunk_status;
 }
 
-struct lttng_index_file *lttng_index_file_create_from_trace_chunk(
+enum lttng_trace_chunk_status lttng_index_file_create_from_trace_chunk(
                struct lttng_trace_chunk *chunk,
                const char *channel_path, const char *stream_name,
                uint64_t stream_file_size, uint64_t stream_file_index,
                uint32_t index_major, uint32_t index_minor,
-               bool unlink_existing_file)
+               bool unlink_existing_file, struct lttng_index_file **file)
 {
        return _lttng_index_file_create_from_trace_chunk(chunk, channel_path,
                        stream_name, stream_file_size, stream_file_index,
                        index_major, index_minor, unlink_existing_file,
-                       WRITE_FILE_FLAGS);
+                       WRITE_FILE_FLAGS, false, file);
 }
 
-struct lttng_index_file *lttng_index_file_create_from_trace_chunk_read_only(
+enum lttng_trace_chunk_status lttng_index_file_create_from_trace_chunk_read_only(
                struct lttng_trace_chunk *chunk,
                const char *channel_path, const char *stream_name,
                uint64_t stream_file_size, uint64_t stream_file_index,
-               uint32_t index_major, uint32_t index_minor)
+               uint32_t index_major, uint32_t index_minor,
+               bool expect_no_file, struct lttng_index_file **file)
 {
        return _lttng_index_file_create_from_trace_chunk(chunk, channel_path,
                        stream_name, stream_file_size, stream_file_index,
                        index_major, index_minor, false,
-                       READ_ONLY_FILE_FLAGS);
+                       READ_ONLY_FILE_FLAGS, expect_no_file, file);
 }
 
 /*

diff --git a/src/common/index/index.h b/src/common/index/index.h
index 3dbe458f3985cc6ab7b702e0afd501e96bc96dd5..f42e31e2dee748490fe399393e8838c622a1c931 100644 (file)
--- a/src/common/index/index.h
+++ b/src/common/index/index.h
@@ -39,17 +39,20 @@ struct lttng_index_file {
  * create and open have refcount of 1. Use put to decrement the
  * refcount. Destroys when reaching 0. Use "get" to increment refcount.
  */
-struct lttng_index_file *lttng_index_file_create_from_trace_chunk(
+enum lttng_trace_chunk_status lttng_index_file_create_from_trace_chunk(
                struct lttng_trace_chunk *chunk,
                const char *channel_path, const char *stream_name,
                uint64_t stream_file_size, uint64_t stream_count,
                uint32_t index_major, uint32_t index_minor,
-               bool unlink_existing_file);
-struct lttng_index_file *lttng_index_file_create_from_trace_chunk_read_only(
+               bool unlink_existing_file, struct lttng_index_file **file);
+
+enum lttng_trace_chunk_status lttng_index_file_create_from_trace_chunk_read_only(
                struct lttng_trace_chunk *chunk,
                const char *channel_path, const char *stream_name,
                uint64_t stream_file_size, uint64_t stream_file_index,
-               uint32_t index_major, uint32_t index_minor);
+               uint32_t index_major, uint32_t index_minor,
+               bool expect_no_file, struct lttng_index_file **file);
+
 int lttng_index_file_write(const struct lttng_index_file *index_file,
                const struct ctf_packet_index *element);
 int lttng_index_file_read(const struct lttng_index_file *index_file,

diff --git a/src/common/trace-chunk.c b/src/common/trace-chunk.c
index 6181520fa7362b8b18732658fde146534a7dde01..aadb40f6f68383a174304cc912c2beb2880a86fd 100644 (file)
--- a/src/common/trace-chunk.c
+++ b/src/common/trace-chunk.c
@@ -816,7 +816,7 @@ end:
 LTTNG_HIDDEN
 enum lttng_trace_chunk_status lttng_trace_chunk_open_file(
                struct lttng_trace_chunk *chunk, const char *file_path,
-               int flags, mode_t mode, int *out_fd)
+               int flags, mode_t mode, int *out_fd, bool expect_no_file)
 {
        int ret;
        enum lttng_trace_chunk_status status = LTTNG_TRACE_CHUNK_STATUS_OK;
@@ -844,9 +844,13 @@ enum lttng_trace_chunk_status lttng_trace_chunk_open_file(
                        chunk->credentials.value.use_current_user ?
                                        NULL : &chunk->credentials.value.user);
        if (ret < 0) {
-               PERROR("Failed to open file relative to trace chunk file_path = \"%s\", flags = %d, mode = %d",
+               if (errno == ENOENT && expect_no_file) {
+                       status = LTTNG_TRACE_CHUNK_STATUS_NO_FILE;
+               } else {
+                       PERROR("Failed to open file relative to trace chunk file_path = \"%s\", flags = %d, mode = %d",
                                file_path, flags, (int) mode);
-               status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
+                       status = LTTNG_TRACE_CHUNK_STATUS_ERROR;
+               }
                goto end;
        }
        *out_fd = ret;

diff --git a/src/common/trace-chunk.h b/src/common/trace-chunk.h
index fcacb01ff80070d07f09e473a00693863243bc2f..b90daf8ae823798c9ff8ae3b439afd73c674fed2 100644 (file)
--- a/src/common/trace-chunk.h
+++ b/src/common/trace-chunk.h
@@ -68,6 +68,7 @@ enum lttng_trace_chunk_status {
        LTTNG_TRACE_CHUNK_STATUS_INVALID_ARGUMENT,
        LTTNG_TRACE_CHUNK_STATUS_INVALID_OPERATION,
        LTTNG_TRACE_CHUNK_STATUS_ERROR,
+       LTTNG_TRACE_CHUNK_STATUS_NO_FILE,
 };
 
 enum lttng_trace_chunk_command_type {
@@ -154,7 +155,7 @@ enum lttng_trace_chunk_status lttng_trace_chunk_create_subdirectory(
 LTTNG_HIDDEN
 enum lttng_trace_chunk_status lttng_trace_chunk_open_file(
                struct lttng_trace_chunk *chunk, const char *filename,
-               int flags, mode_t mode, int *out_fd);
+               int flags, mode_t mode, int *out_fd, bool expect_no_file);
 
 LTTNG_HIDDEN
 int lttng_trace_chunk_unlink_file(struct lttng_trace_chunk *chunk,