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From: David Howells <dhowells@redhat.com>
To: torvalds@linux-foundation.org, viro@zeniv.linux.org.uk
Cc: dhowells@redhat.com, casey@schaufler-ca.com, sds@tycho.nsa.gov,
	nicolas.dichtel@6wind.com, raven@themaw.net,
	christian@brauner.io, andres@anarazel.de, jlayton@redhat.com,
	dray@redhat.com, kzak@redhat.com, keyrings@vger.kernel.org,
	linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 17/17] watch_queue: sample: Display superblock notifications [ver #5]
Date: Wed, 18 Mar 2020 15:05:49 +0000	[thread overview]
Message-ID: <158454394905.2863966.8800154491320171728.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <158454378820.2863966.10496767254293183123.stgit@warthog.procyon.org.uk>

The notification is run as:

	./watch_test

and it then watches "/mnt" for superblock notifications:

	# mount -t tmpfs none /mnt
	# ./watch_test &
	# mount -o remount,ro /mnt
	# mount -o remount,rw /mnt

producing:

	# ./watch_test
	NOTIFY[000]: ty\00003 sy\0 i\x03010010
	SUPER 157eb57ca7 change=0[readonly]
	read() = 16
	NOTIFY[000]: ty\00002 sy\x04 i\x02010010
	MOUNT 000001a0 change=4[setattr] aux=0
	read() = 16
	NOTIFY[000]: ty\00002 sy\x04 i\x02010010
	MOUNT 000001a0 change=4[setattr] aux=0

Signed-off-by: David Howells <dhowells@redhat.com>
---

 samples/watch_queue/watch_test.c |   39 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/samples/watch_queue/watch_test.c b/samples/watch_queue/watch_test.c
index 36caaea5261f..734786bd9764 100644
--- a/samples/watch_queue/watch_test.c
+++ b/samples/watch_queue/watch_test.c
@@ -29,6 +29,9 @@
 #ifndef __NR_watch_mount
 #define __NR_watch_mount -1
 #endif
+#ifndef __NR_watch_sb
+#define __NR_watch_sb -1
+#endif
 
 #define BUF_SIZE 256
 
@@ -87,6 +90,24 @@ static void saw_mount_change(struct watch_notification *n, size_t len)
 
 }
 
+static const char *super_subtypes[256] = {
+	[NOTIFY_SUPERBLOCK_READONLY]	= "readonly",
+	[NOTIFY_SUPERBLOCK_ERROR]	= "error",
+	[NOTIFY_SUPERBLOCK_EDQUOT]	= "edquot",
+	[NOTIFY_SUPERBLOCK_NETWORK]	= "network",
+};
+
+static void saw_super_change(struct watch_notification *n, size_t len)
+{
+	struct superblock_notification *s = (struct superblock_notification *)n;
+
+	if (len < sizeof(struct superblock_notification))
+		return;
+
+	printf("SUPER %08llx change=%u[%s]\n",
+	       s->sb_id, n->subtype, super_subtypes[n->subtype]);
+}
+
 /*
  * Consume and display events.
  */
@@ -166,6 +187,9 @@ static void consumer(int fd)
 			case WATCH_TYPE_MOUNT_NOTIFY:
 				saw_mount_change(&n.n, len);
 				break;
+			case WATCH_TYPE_SB_NOTIFY:
+				saw_super_change(&n.n, len);
+				break;
 			}
 
 			p += len;
@@ -174,7 +198,7 @@ static void consumer(int fd)
 }
 
 static struct watch_notification_filter filter = {
-	.nr_filters	= 2,
+	.nr_filters	= 3,
 	.filters = {
 		[0]	= {
 			.type			= WATCH_TYPE_KEY_NOTIFY,
@@ -185,6 +209,14 @@ static struct watch_notification_filter filter = {
 			// Reject move-from notifications
 			.subtype_filter[0]	= UINT_MAX & ~(1 << NOTIFY_MOUNT_MOVE_FROM),
 		},
+		[2]	= {
+			.type			= WATCH_TYPE_SB_NOTIFY,
+			// Only accept notification of changes to R/O state
+			.subtype_filter[0]	= (1 << NOTIFY_SUPERBLOCK_READONLY),
+			// Only accept notifications of change-to-R/O
+			.info_mask		= WATCH_INFO_FLAG_0,
+			.info_filter		= WATCH_INFO_FLAG_0,
+		},
 	},
 };
 
@@ -223,6 +255,11 @@ int main(int argc, char **argv)
 		exit(1);
 	}
 
+	if (syscall(__NR_watch_sb, AT_FDCWD, "/mnt", 0, fd, 0x03) = -1) {
+		perror("watch_sb");
+		exit(1);
+	}
+
 	consumer(fd);
 	exit(0);
 }

WARNING: multiple messages have this Message-ID
From: David Howells <dhowells@redhat.com>
To: torvalds@linux-foundation.org, viro@zeniv.linux.org.uk
Cc: dhowells@redhat.com, casey@schaufler-ca.com, sds@tycho.nsa.gov,
	nicolas.dichtel@6wind.com, raven@themaw.net,
	christian@brauner.io, andres@anarazel.de, jlayton@redhat.com,
	dray@redhat.com, kzak@redhat.com, keyrings@vger.kernel.org,
	linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-security-module@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 17/17] watch_queue: sample: Display superblock notifications [ver #5]
Date: Wed, 18 Mar 2020 15:05:49 +0000	[thread overview]
Message-ID: <158454394905.2863966.8800154491320171728.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <158454378820.2863966.10496767254293183123.stgit@warthog.procyon.org.uk>

The notification is run as:

	./watch_test

and it then watches "/mnt" for superblock notifications:

	# mount -t tmpfs none /mnt
	# ./watch_test &
	# mount -o remount,ro /mnt
	# mount -o remount,rw /mnt

producing:

	# ./watch_test
	NOTIFY[000]: ty=000003 sy=00 i=03010010
	SUPER 157eb57ca7 change=0[readonly]
	read() = 16
	NOTIFY[000]: ty=000002 sy=04 i=02010010
	MOUNT 000001a0 change=4[setattr] aux=0
	read() = 16
	NOTIFY[000]: ty=000002 sy=04 i=02010010
	MOUNT 000001a0 change=4[setattr] aux=0

Signed-off-by: David Howells <dhowells@redhat.com>
---

 samples/watch_queue/watch_test.c |   39 +++++++++++++++++++++++++++++++++++++-
 1 file changed, 38 insertions(+), 1 deletion(-)

diff --git a/samples/watch_queue/watch_test.c b/samples/watch_queue/watch_test.c
index 36caaea5261f..734786bd9764 100644
--- a/samples/watch_queue/watch_test.c
+++ b/samples/watch_queue/watch_test.c
@@ -29,6 +29,9 @@
 #ifndef __NR_watch_mount
 #define __NR_watch_mount -1
 #endif
+#ifndef __NR_watch_sb
+#define __NR_watch_sb -1
+#endif
 
 #define BUF_SIZE 256
 
@@ -87,6 +90,24 @@ static void saw_mount_change(struct watch_notification *n, size_t len)
 
 }
 
+static const char *super_subtypes[256] = {
+	[NOTIFY_SUPERBLOCK_READONLY]	= "readonly",
+	[NOTIFY_SUPERBLOCK_ERROR]	= "error",
+	[NOTIFY_SUPERBLOCK_EDQUOT]	= "edquot",
+	[NOTIFY_SUPERBLOCK_NETWORK]	= "network",
+};
+
+static void saw_super_change(struct watch_notification *n, size_t len)
+{
+	struct superblock_notification *s = (struct superblock_notification *)n;
+
+	if (len < sizeof(struct superblock_notification))
+		return;
+
+	printf("SUPER %08llx change=%u[%s]\n",
+	       s->sb_id, n->subtype, super_subtypes[n->subtype]);
+}
+
 /*
  * Consume and display events.
  */
@@ -166,6 +187,9 @@ static void consumer(int fd)
 			case WATCH_TYPE_MOUNT_NOTIFY:
 				saw_mount_change(&n.n, len);
 				break;
+			case WATCH_TYPE_SB_NOTIFY:
+				saw_super_change(&n.n, len);
+				break;
 			}
 
 			p += len;
@@ -174,7 +198,7 @@ static void consumer(int fd)
 }
 
 static struct watch_notification_filter filter = {
-	.nr_filters	= 2,
+	.nr_filters	= 3,
 	.filters = {
 		[0]	= {
 			.type			= WATCH_TYPE_KEY_NOTIFY,
@@ -185,6 +209,14 @@ static struct watch_notification_filter filter = {
 			// Reject move-from notifications
 			.subtype_filter[0]	= UINT_MAX & ~(1 << NOTIFY_MOUNT_MOVE_FROM),
 		},
+		[2]	= {
+			.type			= WATCH_TYPE_SB_NOTIFY,
+			// Only accept notification of changes to R/O state
+			.subtype_filter[0]	= (1 << NOTIFY_SUPERBLOCK_READONLY),
+			// Only accept notifications of change-to-R/O
+			.info_mask		= WATCH_INFO_FLAG_0,
+			.info_filter		= WATCH_INFO_FLAG_0,
+		},
 	},
 };
 
@@ -223,6 +255,11 @@ int main(int argc, char **argv)
 		exit(1);
 	}
 
+	if (syscall(__NR_watch_sb, AT_FDCWD, "/mnt", 0, fd, 0x03) == -1) {
+		perror("watch_sb");
+		exit(1);
+	}
+
 	consumer(fd);
 	exit(0);
 }



  parent reply	other threads:[~2020-03-18 15:05 UTC|newest]

Thread overview: 87+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-18 15:03 [PATCH 00/17] pipe: Keyrings, mount and " David Howells
2020-03-18 15:03 ` David Howells
2020-03-18 15:03 ` [PATCH 01/17] uapi: General notification queue definitions " David Howells
2020-03-18 15:03 ` [PATCH 02/17] security: Add hooks to rule on setting a watch " David Howells
2020-03-18 15:03   ` David Howells
2020-03-18 18:56   ` James Morris
2020-03-18 18:56     ` James Morris
2020-03-18 15:03 ` [PATCH 03/17] security: Add a hook for the point of notification insertion " David Howells
2020-03-18 15:03   ` David Howells
2020-03-18 18:57   ` James Morris
2020-03-18 18:57     ` James Morris
2020-03-18 15:03 ` [PATCH 04/17] pipe: Add O_NOTIFICATION_PIPE " David Howells
2020-03-18 15:03 ` [PATCH 05/17] pipe: Add general notification queue support " David Howells
2020-03-18 15:03   ` David Howells
2020-03-18 15:04 ` [PATCH 06/17] watch_queue: Add a key/keyring notification facility " David Howells
2020-03-18 15:04   ` David Howells
2020-03-18 19:04   ` James Morris
2020-03-18 19:04     ` James Morris
2020-03-18 15:04 ` [PATCH 07/17] Add sample notification program " David Howells
2020-03-18 15:04   ` David Howells
2020-03-18 15:04 ` [PATCH 08/17] pipe: Allow buffers to be marked read-whole-or-error for notifications " David Howells
2020-03-18 15:04   ` David Howells
2020-03-18 15:04 ` [PATCH 09/17] pipe: Add notification lossage handling " David Howells
2020-03-18 15:04   ` David Howells
2020-03-18 15:04 ` [PATCH 10/17] selinux: Implement the watch_key security hook " David Howells
2020-03-18 15:04   ` David Howells
2020-03-18 19:06   ` James Morris
2020-03-18 19:06     ` James Morris
2020-03-18 15:04 ` [PATCH 11/17] smack: Implement the watch_key and post_notification hooks " David Howells
2020-03-18 15:04   ` David Howells
2020-03-18 15:05 ` [PATCH 12/17] watch_queue: Add security hooks to rule on setting mount and sb watches " David Howells
2020-03-18 15:05   ` David Howells
2020-03-18 19:07   ` James Morris
2020-03-18 19:07     ` James Morris
2020-03-18 15:05 ` [PATCH 13/17] watch_queue: Implement mount topology and attribute change notifications " David Howells
2020-03-18 15:05   ` David Howells
2020-04-02 15:19   ` Miklos Szeredi
2020-04-02 15:19     ` Miklos Szeredi
2020-06-14  3:07     ` Ian Kent
2020-06-14  3:07       ` Ian Kent
2020-06-15  8:44       ` Miklos Szeredi
2020-06-15  8:44         ` Miklos Szeredi
2020-07-23 10:48   ` David Howells
2020-07-23 10:48     ` David Howells
2020-08-03  9:29     ` Miklos Szeredi
2020-08-03  9:29       ` Miklos Szeredi
2020-08-04 11:38       ` Ian Kent
2020-08-04 11:38         ` Ian Kent
2020-08-04 13:19         ` Miklos Szeredi
2020-08-04 13:19           ` Miklos Szeredi
2020-08-05  1:53           ` Ian Kent
2020-08-05  1:53             ` Ian Kent
2020-08-05  7:43             ` Miklos Szeredi
2020-08-05  7:43               ` Miklos Szeredi
2020-08-05 11:36               ` Ian Kent
2020-08-05 11:36                 ` Ian Kent
2020-08-05 11:56                 ` Miklos Szeredi
2020-08-05 11:56                   ` Miklos Szeredi
2020-07-24 10:19   ` David Howells
2020-07-24 10:19     ` David Howells
2020-07-24 10:44     ` Ian Kent
2020-07-24 10:44       ` Ian Kent
2020-07-24 11:36     ` David Howells
2020-07-24 11:36       ` David Howells
2020-08-03 10:02       ` Miklos Szeredi
2020-08-03 10:02         ` Miklos Szeredi
2020-08-03 10:08       ` David Howells
2020-08-03 10:08         ` David Howells
2020-08-03 10:18       ` David Howells
2020-08-03 10:18         ` David Howells
2020-08-03 11:17         ` Miklos Szeredi
2020-08-03 11:17           ` Miklos Szeredi
2020-08-03 11:49         ` David Howells
2020-08-03 11:49           ` David Howells
2020-08-03 12:01           ` Ian Kent
2020-08-03 12:01             ` Ian Kent
2020-08-03 12:31           ` David Howells
2020-08-03 12:31             ` David Howells
2020-08-03 14:30             ` Ian Kent
2020-08-03 14:30               ` Ian Kent
2020-03-18 15:05 ` [PATCH 14/17] watch_queue: sample: Display mount tree " David Howells
2020-03-18 15:05   ` David Howells
2020-03-18 15:05 ` [PATCH 15/17] watch_queue: Introduce a non-repeating system-unique superblock ID " David Howells
2020-03-18 15:05 ` [PATCH 16/17] watch_queue: Add superblock notifications " David Howells
2020-03-18 15:05   ` David Howells
2020-03-18 15:05 ` David Howells [this message]
2020-03-18 15:05   ` [PATCH 17/17] watch_queue: sample: Display " David Howells

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