From: Thomas Weißschuh <thomas@t-8ch.de>
Date: Fri, 13 Oct 2023 14:44:51 +0000 (+0200)
Subject: wdctl: use only sysfs if sufficient
X-Git-Tag: v2.40-rc1~200^2
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=6de3def84cf48b68b79d0cc4b5e1d2696e0484d1;p=thirdparty%2Futil-linux.git

wdctl: use only sysfs if sufficient

Also avoid opening device if nowayout is set.

Opening the device node starts the watchdog.
With 'nowayout' enabled unstoppably.

Also the device node can only be opened once at the same time which can
be problematic.

Prefer to retrieve the information via sysfs which does not have such
problems.

Fixes #2543

Signed-off-by: Thomas Weißschuh <thomas@t-8ch.de>
---

diff --git a/sys-utils/wdctl.c b/sys-utils/wdctl.c
index a5fdeaeb22..767f061fea 100644
--- a/sys-utils/wdctl.c
+++ b/sys-utils/wdctl.c
@@ -125,7 +125,12 @@ struct wd_device {
 
 	struct watchdog_info ident;
 
-	unsigned int	has_timeout : 1,
+	unsigned int	has_identity : 1,
+			has_fw_version : 1,
+			has_options : 1,
+			has_status : 1,
+			has_bootstatus : 1,
+			has_timeout : 1,
 			has_timeleft : 1,
 			has_pretimeout : 1,
 			has_nowayout : 1,
@@ -549,13 +554,16 @@ static int read_watchdog_from_sysfs(struct wd_device *wd)
 	if (!sys)
 		return 1;
 
-	ul_path_read_buffer(sys, (char *) wd->ident.identity, sizeof(wd->ident.identity), "identity");
-	ul_path_read_u32(sys, &wd->ident.firmware_version, "fw_version");
-	ul_path_scanf(sys, "options", "%x", &wd->ident.options);
-
-	ul_path_scanf(sys, "status", "%x", &wd->status);
-	ul_path_read_u32(sys, &wd->bstatus, "bootstatus");
-
+	if (ul_path_read_buffer(sys, (char *) wd->ident.identity, sizeof(wd->ident.identity), "identity") >= 0)
+		wd->has_identity = 1;
+	if (ul_path_read_u32(sys, &wd->ident.firmware_version, "fw_version") == 0)
+		wd->has_fw_version = 1;
+	if (ul_path_scanf(sys, "options", "%x", &wd->ident.options) == 1)
+		wd->has_options = 1;
+	if (ul_path_scanf(sys, "status", "%x", &wd->status) == 1)
+		wd->has_status = 1;
+	if (ul_path_read_u32(sys, &wd->bstatus, "bootstatus") == 0)
+		wd->has_bootstatus = 1;
 	if (ul_path_read_s32(sys, &wd->nowayout, "nowayout") == 0)
 		wd->has_nowayout = 1;
 	if (ul_path_read_s32(sys, &wd->timeout, "timeout") == 0)
@@ -598,12 +606,32 @@ static int read_governors(struct wd_device *wd)
 	return 0;
 }
 
+static bool should_read_from_device(struct wd_device *wd)
+{
+	if (!wd->has_nowayout)
+		return false;
+
+	if (wd->nowayout)
+		return false;
+
+	return !wd->has_identity ||
+	       !wd->has_fw_version ||
+	       !wd->has_options ||
+	       !wd->has_status ||
+	       !wd->has_bootstatus ||
+	       !wd->has_timeout ||
+	       !wd->has_timeleft;
+	       // pretimeout attribute may be hidden in sysfs
+}
+
 static int read_watchdog(struct wd_device *wd)
 {
-	int rc = read_watchdog_from_device(wd);
+	int rc;
+
+	rc = read_watchdog_from_sysfs(wd);
 
-	if (rc == -EBUSY || rc == -EACCES || rc == -EPERM)
-		rc = read_watchdog_from_sysfs(wd);
+	if (rc && should_read_from_device(wd))
+		rc = read_watchdog_from_device(wd);
 
 	if (rc) {
 		warn(_("cannot read information about %s"), wd->devpath);