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

Adrian Hunter
2022-07-11T10:13:10Z

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>
---
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