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weston-log-flight-rec: Add a global variable to access the ring buffer

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With it add also a function which can be used in an assert()-like
situation to display the contents of the ring buffer. Within gdb
this call also be called if the program is loaded/still loaded into
memory.

The global variable will be used in a later patch to be accessed from a
python gdb script.

Signed-off-by: Marius Vlad <marius.vlad@collabora.com>
This commit is contained in:
Marius Vlad 2019-07-18 17:04:37 +03:00 committed by Daniel Stone
parent bdfc11cd1b
commit b1f5f8076a
2 changed files with 50 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

3
include/libweston/weston-log.h
View File

@ -126,6 +126,9 @@ struct weston_log_subscription *
weston_log_subscription_iterate(struct weston_log_scope *scope,
struct weston_log_subscription *sub_iter);
void
weston_log_flight_recorder_display_buffer(FILE *file);
#ifdef __cplusplus
}
#endif

59
libweston/weston-log-flight-rec.c
View File

@ -46,6 +46,10 @@ struct weston_ring_buffer {
bool overlap; /**< in case buff overlaps, hint from where to print buf contents */
};
/** allows easy access to the ring buffer in case of a core dump
*/
WL_EXPORT struct weston_ring_buffer *weston_primary_flight_recorder_ring_buffer = NULL;
/** A black box type of stream, used to aggregate data continuously, and
* when needed, to dump its contents for inspection.
*/
@ -182,6 +186,28 @@ weston_log_flight_recorder_map_memory(struct weston_debug_log_flight_recorder *f
flight_rec->rb.buf[i] = 0xff;
}
static void
weston_log_subscriber_display_flight_rec_data(struct weston_ring_buffer *rb,
FILE *file)
{
FILE *file_d = stderr;
if (file)
file_d = file;
if (rb->append_pos <= rb->size && !rb->overlap) {
if (rb->append_pos)
fwrite(rb->buf, sizeof(char), rb->append_pos, file_d);
else
fwrite(rb->buf, sizeof(char), rb->size, file_d);
} else {
/* from append_pos to size */
fwrite(&rb->buf[rb->append_pos], sizeof(char),
rb->size - rb->append_pos, file_d);
/* from 0 to append_pos */
fwrite(rb->buf, sizeof(char), rb->append_pos, file_d);
}
}
WL_EXPORT void
weston_log_subscriber_display_flight_rec(struct weston_log_subscriber *sub)
{
@ -189,18 +215,7 @@ weston_log_subscriber_display_flight_rec(struct weston_log_subscriber *sub)
to_flight_recorder(sub);
struct weston_ring_buffer *rb = &flight_rec->rb;
if (rb->append_pos <= rb->size && !rb->overlap) {
if (rb->append_pos)
fwrite(rb->buf, sizeof(char), rb->append_pos, rb->file);
else
fwrite(rb->buf, sizeof(char), rb->size, rb->file);
} else {
/* from append_pos to size */
fwrite(&rb->buf[rb->append_pos], sizeof(char),
rb->size - rb->append_pos, rb->file);
/* from 0 to append_pos */
fwrite(rb->buf, sizeof(char), rb->append_pos, rb->file);
}
weston_log_subscriber_display_flight_rec_data(rb, rb->file);
}
/** Create a flight recorder type of subscriber
@ -234,6 +249,7 @@ weston_log_subscriber_create_flight_rec(size_t size)
}
weston_ring_buffer_init(&flight_rec->rb, size, weston_rb);
weston_primary_flight_recorder_ring_buffer = &flight_rec->rb;
/* write some data to the rb such that the memory gets mapped */
weston_log_flight_recorder_map_memory(flight_rec);
@ -254,3 +270,22 @@ weston_log_subscriber_destroy_flight_rec(struct weston_log_subscriber *sub)
free(flight_rec->rb.buf);
free(flight_rec);
}
/** Retrieve flight recorder ring buffer contents, could be useful when
* implementing an assert()-like wrapper.
*
* @param file a FILE type already opened. Can also pass stderr/stdout under gdb
* if the program is loaded into memory.
*
* Uses the global exposed weston_primary_flight_recorder_ring_buffer.
*
*/
WL_EXPORT void
weston_log_flight_recorder_display_buffer(FILE *file)
{
if (!weston_primary_flight_recorder_ring_buffer)
return;
weston_log_subscriber_display_flight_rec_data(weston_primary_flight_recorder_ring_buffer,
file);
}