Re: [PATCH 21/35] perf tools: Make has_kcore_dir() work also for guest kcore_dir

Ian Rogers
2022-07-20T00:49:23Z

On Mon, Jul 11, 2022 at 2:33 AM Adrian Hunter <adrian.hunter@intel.com> wrote:
>
> Copies of /proc/kallsyms, /proc/modules and an extract of /proc/kcore can
> be stored in the perf.data output directory under the subdirectory named
> kcore_dir. Guest machines will have their files also under subdirectories
> beginning kcore_dir__ followed by the machine pid. Make has_kcore_dir()
> return true also if there is a guest machine kcore_dir.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>

Acked-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> ---
> tools/perf/util/data.c | 24 +++++++++++++++---------
> 1 file changed, 15 insertions(+), 9 deletions(-)
>
> diff --git a/tools/perf/util/data.c b/tools/perf/util/data.c
> index caabeac24c69..9782ccbe595d 100644
> --- a/tools/perf/util/data.c
> +++ b/tools/perf/util/data.c
> @@ -3,6 +3,7 @@
> #include <linux/kernel.h>
> #include <linux/string.h>
> #include <linux/zalloc.h>
> +#include <linux/err.h>
> #include <sys/types.h>
> #include <sys/stat.h>
> #include <errno.h>
> @@ -481,16 +482,21 @@ int perf_data__make_kcore_dir(struct perf_data *data, char *buf, size_t buf_sz)
>
> bool has_kcore_dir(const char *path)
> {
> - char *kcore_dir;
> - int ret;
> -
> - if (asprintf(&kcore_dir, "%s/kcore_dir", path) < 0)
> - return false;
> -
> - ret = access(kcore_dir, F_OK);
> + struct dirent *d = ERR_PTR(-EINVAL);
> + const char *name = "kcore_dir";
> + DIR *dir = opendir(path);
> + size_t n = strlen(name);
> + bool result = false;
> +
> + if (dir) {
> + while (d && !result) {
> + d = readdir(dir);
> + result = d ? strncmp(d->d_name, name, n) : false;
> + }
> + closedir(dir);
> + }
>
> - free(kcore_dir);
> - return !ret;
> + return result;
> }
>
> char *perf_data__kallsyms_name(struct perf_data *data)
> --
> 2.25.1
>