From: Karel Zak <kzak@redhat.com>
Date: Wed, 21 May 2025 10:39:17 +0000 (+0200)
Subject: libmount: (monitor) support additional monitor identifiers
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=3285ebe18773dfcd6ed7ae7a1a9952d0abb3fb04;p=thirdparty%2Futil-linux.git

libmount: (monitor) support additional monitor identifiers

This is necessary to support multiple monitors of the same type.
Currently, only one monitor per type is supported.

Signed-off-by: Karel Zak <kzak@redhat.com>
---

diff --git a/libmount/src/monitor.c b/libmount/src/monitor.c
index fb68d0d67..3044dcf68 100644
--- a/libmount/src/monitor.c
+++ b/libmount/src/monitor.c
@@ -124,6 +124,7 @@ struct monitor_entry *monitor_new_entry(struct libmnt_monitor *mn)
 	list_add_tail(&me->ents, &mn->ents);
 
 	me->fd = -1;
+	me->id = -1;
 
 	return me;
 }
@@ -153,14 +154,14 @@ static int monitor_next_entry(struct libmnt_monitor *mn,
 }
 
 /* returns entry by type */
-struct monitor_entry *monitor_get_entry(struct libmnt_monitor *mn, int type)
+struct monitor_entry *monitor_get_entry(struct libmnt_monitor *mn, int type, int id)
 {
 	struct libmnt_iter itr;
 	struct monitor_entry *me;
 
 	mnt_reset_iter(&itr, MNT_ITER_FORWARD);
 	while (monitor_next_entry(mn, &itr, &me) == 0) {
-		if (me->type == type)
+		if (me->type == type && me->id == id)
 			return me;
 	}
 	return NULL;
diff --git a/libmount/src/monitor.h b/libmount/src/monitor.h
index a72658e95..6c6ba4450 100644
--- a/libmount/src/monitor.h
+++ b/libmount/src/monitor.h
@@ -8,6 +8,7 @@ struct monitor_opers;
 
 struct monitor_entry {
 	int			fd;		/* private entry file descriptor */
+	int			id;		/* external identifier (-1 for undefined) */
 	char			*path;		/* path to the monitored file */
 	int			type;		/* MNT_MONITOR_TYPE_* */
 	uint32_t		events;		/* wanted epoll events */
@@ -36,7 +37,7 @@ struct monitor_opers {
 };
 
 int monitor_modify_epoll(struct libmnt_monitor *mn, struct monitor_entry *me, int enable);
-struct monitor_entry *monitor_get_entry(struct libmnt_monitor *mn, int type);
+struct monitor_entry *monitor_get_entry(struct libmnt_monitor *mn, int type, int id);
 struct monitor_entry *monitor_new_entry(struct libmnt_monitor *mn);
 void free_monitor_entry(struct monitor_entry *me);
 
diff --git a/libmount/src/monitor_mountinfo.c b/libmount/src/monitor_mountinfo.c
index 56171fd91..3bffcb31f 100644
--- a/libmount/src/monitor_mountinfo.c
+++ b/libmount/src/monitor_mountinfo.c
@@ -99,7 +99,7 @@ int mnt_monitor_enable_kernel(struct libmnt_monitor *mn, int enable)
 	if (!mn)
 		return -EINVAL;
 
-	me = monitor_get_entry(mn, MNT_MONITOR_TYPE_KERNEL);
+	me = monitor_get_entry(mn, MNT_MONITOR_TYPE_KERNEL, -1);
 	if (me) {
 		rc = monitor_modify_epoll(mn, me, enable);
 		if (!enable)
diff --git a/libmount/src/monitor_utab.c b/libmount/src/monitor_utab.c
index d7261a947..593e16329 100644
--- a/libmount/src/monitor_utab.c
+++ b/libmount/src/monitor_utab.c
@@ -209,7 +209,7 @@ int mnt_monitor_enable_userspace(struct libmnt_monitor *mn, int enable, const ch
 	if (!mn)
 		return -EINVAL;
 
-	me = monitor_get_entry(mn, MNT_MONITOR_TYPE_USERSPACE);
+	me = monitor_get_entry(mn, MNT_MONITOR_TYPE_USERSPACE, -1);
 	if (me) {
 		rc = monitor_modify_epoll(mn, me, enable);
 		if (!enable)