On Tue, Apr 09, 2024 at 02:36:01PM +0200, Jiri Olsa wrote:
SNIP
> +int read_trace_pipe_iter(void (*cb)(const char *str, void *data), void *data, int iter)
> +{
> + char *buf = NULL;
> + FILE *fp = NULL;
> + size_t buflen;
> +
> + if (access(TRACEFS_PIPE, F_OK) == 0)
> + fp = fopen(TRACEFS_PIPE, "r");
> + else
> + fp = fopen(DEBUGFS_PIPE, "r");
> + if (!fp)
> + return -1;
> +
> + /* We do not want to wait forever when iter is specified. */
> + if (iter)
> + fcntl(fileno(fp), F_SETFL, O_NONBLOCK);
> +
> + while (getline(&buf, &buflen, fp) >= 0 || errno == EAGAIN) {
> + cb(buf, data);
> + if (iter && !(--iter))
> + break;
> + }
hm, using this in some other changes shows that the original code
is not completely right and we need this change as well:
+ while ((n = getline(&buf, &buflen, fp) >= 0) || errno == EAGAIN) {
+ if (n > 0)
+ cb(buf, data);
I'll send new version
jirka
> +
> + free(buf);
> + if (fp)
> + fclose(fp);
> + return 0;
> +}
> +
> +static void trace_pipe_cb(const char *str, void *data)
> +{
> + printf("%s", str);
> +}
> +
> +void read_trace_pipe(void)
> +{
> + read_trace_pipe_iter(trace_pipe_cb, NULL, 0);
> +}
> diff --git a/tools/testing/selftests/bpf/trace_helpers.h b/tools/testing/selftests/bpf/trace_helpers.h
> index d1ed71789049..2ce873c9f9aa 100644
> --- a/tools/testing/selftests/bpf/trace_helpers.h
> +++ b/tools/testing/selftests/bpf/trace_helpers.h
> @@ -33,6 +33,8 @@ struct ksym *search_kallsyms_custom_local(struct ksyms *ksyms, const void *p1,
> int kallsyms_find(const char *sym, unsigned long long *addr);
>
> void read_trace_pipe(void);
> +int read_trace_pipe_iter(void (*cb)(const char *str, void *data),
> + void *data, int iter);
>
> ssize_t get_uprobe_offset(const void *addr);
> ssize_t get_rel_offset(uintptr_t addr);
> --
> 2.44.0
>
