On Fri, 10 Dec 2021 12:54:40 +0200
"Tzvetomir Stoyanov (VMware)" <tz.stoyanov@xxxxxxxxx> wrote:
> Internal strings database is added to trace input handle, containing all
> metadata strings from trace file. When a trace file is opened, all
> strings sections are located and the internal strings database is
> initialised.
>
> Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@xxxxxxxxx>
> ---
> lib/trace-cmd/include/trace-cmd-local.h | 1 +
> lib/trace-cmd/trace-input.c | 64 +++++++++++++++++++++++++
> lib/trace-cmd/trace-output.c | 1 +
> 3 files changed, 66 insertions(+)
>
> diff --git a/lib/trace-cmd/include/trace-cmd-local.h b/lib/trace-cmd/include/trace-cmd-local.h
> index 4a0a691c..ac7e7f17 100644
> --- a/lib/trace-cmd/include/trace-cmd-local.h
> +++ b/lib/trace-cmd/include/trace-cmd-local.h
> @@ -53,5 +53,6 @@ struct cpu_data_source {
> int out_write_cpu_data(struct tracecmd_output *handle, int cpus,
> struct cpu_data_source *data, const char *buff_name);
> off64_t msg_lseek(struct tracecmd_msg_handle *msg_handle, off_t offset, int whence);
> +unsigned int get_meta_strings_size(struct tracecmd_input *handle);
>
> #endif /* _TRACE_CMD_LOCAL_H */
> diff --git a/lib/trace-cmd/trace-input.c b/lib/trace-cmd/trace-input.c
> index 9027729e..6cc8ee90 100644
> --- a/lib/trace-cmd/trace-input.c
> +++ b/lib/trace-cmd/trace-input.c
> @@ -147,6 +147,9 @@ struct tracecmd_input {
> long long ts_offset;
> struct tsc2nsec tsc_calc;
>
> + unsigned int strings_size; /* size of the metadata strings */
> + char *strings; /* metadata strings */
> +
> struct host_trace_info host;
> double ts2secs;
> char * cpustats;
> @@ -984,6 +987,14 @@ static int read_headers_v6(struct tracecmd_input *handle, enum tracecmd_file_sta
>
> static int handle_options(struct tracecmd_input *handle);
>
> +static const char *get_metadata_string(struct tracecmd_input *handle, int offset)
> +{
> + if (!handle || !handle->strings || offset < 0 || handle->strings_size >= offset)
> + return NULL;
> +
> + return handle->strings + offset;
> +}
> +
> static int read_section_header(struct tracecmd_input *handle, unsigned short *id,
> unsigned short *flags, unsigned long long *size, const char **description)
> {
> @@ -1007,6 +1018,8 @@ static int read_section_header(struct tracecmd_input *handle, unsigned short *id
> *flags = fl;
> if (size)
> *size = sz;
> + if (description)
> + *description = get_metadata_string(handle, desc);
>
> return 0;
> }
> @@ -2839,6 +2852,11 @@ tracecmd_search_task_map(struct tracecmd_input *handle,
> return lib;
> }
>
> +__hidden unsigned int get_meta_strings_size(struct tracecmd_input *handle)
> +{
> + return handle->strings_size;
> +}
> +
> static int handle_options(struct tracecmd_input *handle)
> {
> long long offset;
> @@ -3472,6 +3490,50 @@ struct hook_list *tracecmd_hooks(struct tracecmd_input *handle)
> return handle->hooks;
> }
>
> +static int init_metadata_strings(struct tracecmd_input *handle, int size)
> +{
> + char *tmp;
> +
> + tmp = realloc(handle->strings, handle->strings_size + size);
Hmm, I don't remember in our conversations. Did we say we would have more
than one string section? Or allow it to be broken up? How do offsets work
in such cases?
I was thinking that we could simply mmap the string section, but that won't
work if there's more than one.
-- Steve
> + if (!tmp)
> + return -1;
> +
> + handle->strings = tmp;
> + if (do_read_check(handle, handle->strings + handle->strings_size, size))
> + return -1;
> +
> + handle->strings_size += size;
> +
> + return 0;
> +}
> +
> +static int read_metadata_strings(struct tracecmd_input *handle)
> +{
> + unsigned short flags;
> + int found = 0;
> + unsigned short id;
> + unsigned long long size;
> + off64_t offset;
> +
> + offset = lseek64(handle->fd, 0, SEEK_CUR);
> + do {
> + if (read_section_header(handle, &id, &flags, &size, NULL))
> + break;
> + if (id == TRACECMD_OPTION_STRINGS) {
> + found++;
> + init_metadata_strings(handle, size);
> + } else {
> + if (lseek64(handle->fd, size, SEEK_CUR) == (off_t)-1)
> + break;
> + }
> + } while (1);
> +
> + if (lseek64(handle->fd, offset, SEEK_SET) == (off_t)-1)
> + return -1;
> +
> + return found ? 0 : -1;
> +}
> +
> /**
> * tracecmd_alloc_fd - create a tracecmd_input handle from a file descriptor
> * @fd: the file descriptor for the trace.dat file
> @@ -3568,6 +3630,7 @@ struct tracecmd_input *tracecmd_alloc_fd(int fd, int flags)
> tracecmd_warning("Filed to read the offset of the first option section");
> goto failed_read;
> }
> + read_metadata_strings(handle);
> }
>
> handle->file_state = TRACECMD_FILE_INIT;
> @@ -3740,6 +3803,7 @@ void tracecmd_close(struct tracecmd_input *handle)
> free(handle->cpu_data);
> free(handle->uname);
> free(handle->trace_clock);
> + free(handle->strings);
> free(handle->version);
> close(handle->fd);
>
> diff --git a/lib/trace-cmd/trace-output.c b/lib/trace-cmd/trace-output.c
> index 47227728..08f74c87 100644
> --- a/lib/trace-cmd/trace-output.c
> +++ b/lib/trace-cmd/trace-output.c
> @@ -2239,6 +2239,7 @@ struct tracecmd_output *tracecmd_get_output_handle_fd(int fd)
> handle->page_size = tracecmd_page_size(ihandle);
> handle->file_version = tracecmd_get_in_file_version(ihandle);
> handle->options_start = tracecmd_get_options_offset(ihandle);
> + handle->strings_offs = get_meta_strings_size(ihandle);
> list_head_init(&handle->options);
> list_head_init(&handle->buffers);
>
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