From 3c97362d2bb26861c04c738b1499451f428c96dc Mon Sep 17 00:00:00 2001
From: zhuofeng <zhuofeng2@huawei.com>
Date: Sat, 29 Jun 2024 17:27:56 +0800
Subject: [PATCH 68/85] The rasdaemon service may fail to be started for the
 first time.

The rasdaemon creates a separate instance virtual directory on first startup, like `/sys/kernel/debug/tracing/instances/rasdaemon`.

After the directory is created, the kernel generates virtual files such as `trace_clock` and `set_event` in `/sys/kernel/debug/tracing/instances/rasdaemon`.

The kernel generates virtual files and the rasdaemon accesses the virtual files at the same time. Therefore, the kernel may not generate the virtual files when the rasdaemon accesses the virtual files.

So add up to 30 seconds to give the kernel enough time to generate the files.

Signed-off-by: zhuofeng <zhuofeng2@huawei.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
---
 ras-events.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/ras-events.c b/ras-events.c
index 0bba53f..9dbbcd0 100644
--- a/ras-events.c
+++ b/ras-events.c
@@ -109,6 +109,19 @@ static int get_debugfs_dir(char *tracing_dir, size_t len)
 	return -ENOENT;
 }
 
+static int wait_access(char *path, int ms)
+{
+	int i;
+	for (i = 0; i < ms; i++) {
+		if (access(path, F_OK) == 0)
+			return 0;
+		usleep(1000);
+	}
+
+	log(ALL, LOG_WARNING, "wait_access() failed, %s not created in %d ms\n", path, ms);
+	return -1;
+}
+
 static int open_trace(struct ras_events *ras, char *name, int flags)
 {
 	char fname[MAX_PATH + 1];
@@ -124,6 +137,12 @@ static int open_trace(struct ras_events *ras, char *name, int flags)
 	if (rc < 0)
 		return rc;
 
+	rc = wait_access(fname, 30000);
+	if (rc != 0) {
+		/* use -1 to keep same error value with open() */
+		return -1;
+	}
+
 	rc = open(fname, flags);
 	if (rc < 0) {
 		rc = -errno;
-- 
2.33.1