On Thu, 29 Jul 2021 08:09:20 +0300
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx> wrote:
> The BUFFER option is extended in trace file version 7. It holds CPU
> metadata related to the recorded CPU traces. Also, there is a new
> BUFFER_LAT option for describing the latency trace data. A new logic
> is implemented for these new options.
> In trace file version 7, the top buffer is saved as other buffers in the
> file, no special treatment. But saving the top buffer in the list of
> buffers in the input handler causes problems. It breaks the legacy logic
> of trace-cmd library users, which have special logic for trace buffers
> processing. That's why "top_buffer" member is added in the input handler
> structure, to hold the top buffer.
>
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
> ---
> lib/trace-cmd/trace-input.c | 116 ++++++++++++++++++++++++++++++------
> 1 file changed, 98 insertions(+), 18 deletions(-)
>
> diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
> index e7f97561..57ae535a 100644
> --- a/lib/trace-cmd/trace-input.c
> +++ b/lib/trace-cmd/trace-input.c
> @@ -74,9 +74,19 @@ struct cpu_data {
> int pipe_fd;
> };
>
> +struct cpu_file_data {
> + int cpu;
> + unsigned long long offset;
> + unsigned long long size;
> +};
> +
> struct input_buffer_instance {
> char *name;
> size_t offset;
> + char *clock;
> + bool latency;
> + int cpus;
> + struct cpu_file_data *cpu_data;
> };
>
> struct ts_offset_sample {
> @@ -155,6 +165,7 @@ struct tracecmd_input {
> char * uname;
> char * version;
> char * trace_clock;
> + struct input_buffer_instance top_buffer;
> struct input_buffer_instance *buffers;
> int parsing_failures;
> struct guest_trace_info *guest;
> @@ -2904,6 +2915,80 @@ tracecmd_search_task_map(struct tracecmd_input *handle,
> return lib;
> }
>
> +#define save_read_number(R, C) \
> + do { \
> + if ((C) > size) \
> + return -1; \
> + (R) = tep_read_number(handle->pevent, (data + rsize), (C)); \
> + rsize += (C); \
> + size -= (C); \
> + } while (0)
> +
> +#define save_read_string(R) \
> + do { \
> + if (size < 1) \
> + return -1; \
> + (R) = strdup(data + rsize); \
> + if (!(R)) \
> + return -1; \
> + rsize += (strlen((R)) + 1); \
> + size -= (strlen((R)) + 1); \
> + if (size < 0) \
> + return -1; \
> + } while (0)
The above should be inline functions, not macros. Just pass the address
of the values you want to modify.
> +
> +static int handle_buffer_option(struct tracecmd_input *handle,
> + unsigned short id, char *data, int size)
> +{
> + struct input_buffer_instance *buff;
> + unsigned long long offset;
> + int rsize = 0;
> + char *name;
> + int i;
> +
> + save_read_number(offset, 8);
> + save_read_string(name);
> +
> + if (*name == '\0') {
> + /* top buffer */
> + buff = &handle->top_buffer;
> + } else {
> + buff = realloc(handle->buffers, sizeof(*handle->buffers) * (handle->nr_buffers + 1));
> + if (!buff) {
> + free(name);
> + return -1;
> + }
> + handle->buffers = buff;
> + handle->nr_buffers++;
> +
> + buff = &handle->buffers[handle->nr_buffers - 1];
> + }
> + memset(buff, 0, sizeof(struct input_buffer_instance));
> + buff->name = name;
> + buff->offset = offset;
> + if (handle->file_version < 7)
> + return 0;
> +
> + /* file version >= 7 specific data */
> + save_read_string(buff->clock);
> + if (id == TRACECMD_OPTION_BUFFER) {
> + save_read_number(buff->cpus, 4);
> + if (!buff->cpus)
> + return 0;
> + buff->cpu_data = calloc(buff->cpus, sizeof(struct cpu_file_data));
> + if (!buff->cpu_data)
> + return -1;
> + for (i = 0; i < buff->cpus; i++) {
> + save_read_number(buff->cpu_data[i].cpu, 4);
> + save_read_number(buff->cpu_data[i].offset, 8);
> + save_read_number(buff->cpu_data[i].size, 8);
> + }
> + } else {
> + buff->latency = true;
> + }
> + return 0;
> +}
> +
> static int handle_options(struct tracecmd_input *handle)
> {
> long long offset;
> @@ -2911,7 +2996,6 @@ static int handle_options(struct tracecmd_input *handle)
> unsigned int size;
> unsigned short id, flags;
> char *cpustats = NULL;
> - struct input_buffer_instance *buffer;
> struct hook_list *hook;
> bool comperss = false;
> char *buf;
> @@ -3016,21 +3100,10 @@ static int handle_options(struct tracecmd_input *handle)
> handle->cpustats = cpustats;
> break;
> case TRACECMD_OPTION_BUFFER:
> - /* A buffer instance is saved at the end of the file */
> - handle->nr_buffers++;
> - handle->buffers = realloc(handle->buffers,
> - sizeof(*handle->buffers) * handle->nr_buffers);
> - if (!handle->buffers)
> - return -ENOMEM;
> - buffer = &handle->buffers[handle->nr_buffers - 1];
> - buffer->name = strdup(buf + 8);
> - if (!buffer->name) {
> - free(handle->buffers);
> - handle->buffers = NULL;
> - return -ENOMEM;
> - }
> - offset = *(unsigned long long *)buf;
> - buffer->offset = tep_read_number(handle->pevent, &offset, 8);
> + case TRACECMD_OPTION_BUFFER_LAT:
> + ret = handle_buffer_option(handle, option, buf, size);
> + if (ret < 0)
> + goto out;
> break;
> case TRACECMD_OPTION_TRACECLOCK:
> if (!handle->ts2secs)
> @@ -3825,9 +3898,15 @@ void tracecmd_close(struct tracecmd_input *handle)
> handle->sections = handle->sections->next;
> free(del_sec);
> }
> - for (i = 0; i < handle->nr_buffers; i++)
> - free(handle->buffers[i].name);
>
> + free(handle->top_buffer.name);
> + free(handle->top_buffer.clock);
> + free(handle->top_buffer.cpu_data);
> + for (i = 0; i < handle->nr_buffers; i++) {
> + free(handle->buffers[i].name);
> + free(handle->buffers[i].clock);
> + free(handle->buffers[i].cpu_data);
> + }
The freeing of the buffer should be a function that encapsulates this,
where all you need to do is:
free_buffer(&handle->top_buffer);
for (i = 0; i < handle->nr_buffers; i++)
free_buffer(&handle->buffers[i]);
-- Steve
> free(handle->buffers);
>
> tracecmd_free_hooks(handle->hooks);
> @@ -4272,6 +4351,7 @@ tracecmd_buffer_instance_handle(struct tracecmd_input *handle, int indx)
> return NULL;
>
> *new_handle = *handle;
> + memset(&new_handle->top_buffer, 0, sizeof(new_handle->top_buffer));
> new_handle->cpu_data = NULL;
> new_handle->nr_buffers = 0;
> new_handle->buffers = NULL;
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