On Fri, 29 Oct 2021 21:26:05 +0200
Daniel Bristot de Oliveira <bristot@xxxxxxxxxx> wrote:
> +/*
> + * enable_tracer_by_name - enable a tracer on the given instance
> + */
> +int enable_tracer_by_name(struct tracefs_instance *inst, const char *tracer)
> +{
> + enum tracefs_tracers t;
> + int retval;
> +
> + t = TRACEFS_TRACER_CUSTOM;
> +
> + debug_msg("enabling %s tracer\n", tracer);
> +
> + retval = tracefs_tracer_set(inst, t, tracer);
Interesting. We had discussions about having the custom option (which I
fought for, for this very reason).
> + if (retval < 0) {
> + if (errno == ENODEV)
> + err_msg("tracer %s not found!\n", tracer);
> +
> + err_msg("failed to enable the tracer %s\n", tracer);
> + return -1;
> + }
> +
> + return 0;
> +}
> +
> +/*
> + * disable_tracer - set nop tracer to the insta
> + */
> +void disable_tracer(struct tracefs_instance *inst)
> +{
> + enum tracefs_tracers t = TRACEFS_TRACER_NOP;
> + int retval;
> +
> + retval = tracefs_tracer_set(inst, t);
> + if (retval < 0)
> + err_msg("oops, error disabling tracer\n");
> +}
> +
> +/*
> + * create_instance - create a trace instance with *instance_name
> + */
> +struct tracefs_instance *create_instance(char *instance_name)
> +{
> + return tracefs_instance_create(instance_name);
> +}
> +
> +/*
> + * destroy_instance - remove a trace instance and free the data
> + */
> +void destroy_instance(struct tracefs_instance *inst)
> +{
> + tracefs_instance_destroy(inst);
> + tracefs_instance_free(inst);
> +}
> +
> +/*
> + * save_trace_to_file - save the trace output of the instance to the file
> + */
> +int save_trace_to_file(struct tracefs_instance *inst, const char *filename)
> +{
> + const char *file = "trace";
> + mode_t mode = 0644;
> + char *buffer[4096];
Did you really mean to have buffer be 4096 strings?
Or did you mean:
char buffer[4096];
(i.e. a single string of 4096 size)?
-- Steve
> + int out_fd, in_fd;
> + int retval = -1;
> +
> + in_fd = tracefs_instance_file_open(inst, file, O_RDONLY);
> + if (in_fd < 0) {
> + err_msg("Failed to open trace file\n");
> + return -1;
> + }
> +
> + out_fd = creat(filename, mode);
> + if (out_fd < 0) {
> + err_msg("Failed to create output file %s\n", filename);
> + goto out_close_in;
> + }
> +
> + do {
> + retval = read(in_fd, buffer, sizeof(buffer));
> + if (retval <= 0)
> + goto out_close;
> +
> + retval = write(out_fd, buffer, retval);
> + if (retval < 0)
> + goto out_close;
> + } while (retval > 0);
> +
> + retval = 0;
> +out_close:
> + close(out_fd);
> +out_close_in:
> + close(in_fd);
> + return retval;
> +}
> +
> +/*
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