dlog_logger: reader_logger keeps dev FD directly

This is in preparation for the future change where each reader
operates from its own thread and manages the FD independently.

Change-Id: Ic2e1637ccfb2ca389a0c154cba1478da6559592f
Signed-off-by: Michal Bloch <m.bloch@samsung.com>

diff --git a/src/logger/reader_logger.c b/src/logger/reader_logger.c
index ca43014..b06cb2b 100644 (file)
--- a/src/logger/reader_logger.c
+++ b/src/logger/reader_logger.c
@@ -2,10 +2,19 @@
 #include "reader_common.h"
 #include "logger_internal.h"
 
-static void free_reader_logger(struct reader_common *reader)
+static void free_reader_logger(struct reader_common *_reader)
 {
-       /* Nothing to cleanup. The Android Logger reader
-        * does everything via sub-readers. */
+       struct reader_logger *const reader = (struct reader_logger *) _reader;
+
+       /* reader_logger is now in a transitory phase where it uses both
+        * the device_fd and the source FD entity, meaning that this FD is
+        * referenced twice (by both). Reset the FD entity because that's
+        * the one that is going to be removed in the future. */
+       assert(reader->common.fd_entity_source.fd == reader->device_fd);
+       reader->common.fd_entity_source.fd = -1;
+
+       if (reader->device_fd != -1)
+               close(reader->device_fd);
 }
 
 static void handle_single_log(struct reader_logger *reader, struct now_t time, int read_count)
@@ -74,7 +83,10 @@ static int service_reader_logger(struct reader_common *_reader, struct now_t tim
         * starvation under heavy load. */
        int max_loop_iterations = g_backend.logger_device_throttling[reader->buf_id];
        while (max_loop_iterations--) {
-               int r = TEMP_FAILURE_RETRY(read(reader->common.fd_entity_source.fd, reader->read_buffer, sizeof reader->read_buffer - 1));
+               /* Note, nominally we had been polling the source FD entity and not
+                * `device_fd`, but that is the same FD (see the init and free ops).
+                * This is temporary redundancy due to the migration to threads. */
+               int r = TEMP_FAILURE_RETRY(read(reader->device_fd, reader->read_buffer, sizeof reader->read_buffer - 1));
                if (r == 0)
                        break;
                else if (r == -1) {
@@ -98,6 +110,7 @@ static struct reader_logger *reader_logger_alloc(void)
 
        reader_common_init(&ret->common);
 
+       ret->device_fd = -1;
        ret->buf_id = LOG_ID_INVALID;
        ret->common.service_reader = service_reader_logger;
        ret->common.free_reader = free_reader_logger;
@@ -148,15 +161,14 @@ int reader_logger_init(struct reader_logger **reader, log_id_t buf_id, struct lo
                return -ENOENT;
        ret->buf_id = buf_id;
 
-       int read_fd = -1;
-       int r = logger_open_buffer(buf_id, config_list, O_RDONLY | O_NONBLOCK, &read_fd);
+       int r = logger_open_buffer(buf_id, config_list, O_RDONLY | O_NONBLOCK, &ret->device_fd);
        if (r <= 0)
                return r;
 
-       ret->skip_count = skip ? logger_get_log_len(read_fd) : 0;
+       ret->skip_count = skip ? logger_get_log_len(ret->device_fd) : 0;
 
        init_fd_entity(&ret->common.fd_entity_source, dispatch_event_reader_logger, ret);
-       set_read_fd_entity(&ret->common.fd_entity_source, read_fd);
+       set_read_fd_entity(&ret->common.fd_entity_source, ret->device_fd);
 
        *reader = ret;
        ret = NULL;

diff --git a/src/logger/reader_logger.h b/src/logger/reader_logger.h
index 14933b9..db4a456 100644 (file)
--- a/src/logger/reader_logger.h
+++ b/src/logger/reader_logger.h
@@ -6,6 +6,7 @@
 
 struct reader_logger {
        struct reader_common common;
+       int device_fd;
        log_id_t buf_id;
        int skip_count;