From: David Howells <dhowells@redhat.com>
To: viro@zeniv.linux.org.uk
Cc: dhowells@redhat.com, Casey Schaufler <casey@schaufler-ca.com>,
Stephen Smalley <sds@tycho.nsa.gov>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
nicolas.dichtel@6wind.com, raven@themaw.net,
Christian Brauner <christian@brauner.io>,
dhowells@redhat.com, keyrings@vger.kernel.org,
linux-usb@vger.kernel.org, linux-security-module@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-api@vger.kernel.org,
linux-block@vger.kernel.org,
linux-security-module@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH 6/6] Add sample notification program [ver #5]
Date: Fri, 28 Jun 2019 16:51:11 +0100 [thread overview]
Message-ID: <156173707116.15650.11875602081597740176.stgit@warthog.procyon.org.uk> (raw)
In-Reply-To: <156173701358.15650.8735203424342507015.stgit@warthog.procyon.org.uk>
This needs to be linked with -lkeyutils.
It is run like:
./watch_test
and watches "/" for mount changes and the current session keyring for key
changes:
# keyctl add user a a @s
1035096409
# keyctl unlink 1035096409 @s
# mount -t tmpfs none /mnt/nfsv3tcp/
# umount /mnt/nfsv3tcp
producing:
# ./watch_test
ptrs h=4 t=2 m=20003
NOTIFY[00000004-00000002] ty=0003 sy=0002 i=01000010
KEY 2ffc2e5d change=2[linked] aux=1035096409
ptrs h=6 t=4 m=20003
NOTIFY[00000006-00000004] ty=0003 sy=0003 i=01000010
KEY 2ffc2e5d change=3[unlinked] aux=1035096409
ptrs h=8 t=6 m=20003
NOTIFY[00000008-00000006] ty=0001 sy=0000 i=02000010
MOUNT 00000013 change=0[new_mount] aux=168
ptrs h=a t=8 m=20003
NOTIFY[0000000a-00000008] ty=0001 sy=0001 i=02000010
MOUNT 00000013 change=1[unmount] aux=168
Other events may be produced, such as with a failing disk:
ptrs h=5 t=2 m=6000004
NOTIFY[00000005-00000002] ty=0004 sy=0006 i=04000018
BLOCK 00800050 e=6[critical medium] s=5be8
This corresponds to:
print_req_error: critical medium error, dev sdf, sector 23528 flags 0
in dmesg.
Signed-off-by: David Howells <dhowells@redhat.com>
---
samples/watch_queue/watch_test.c | 76 ++++++++++++++++++++++++++++++++++++++
1 file changed, 76 insertions(+)
diff --git a/samples/watch_queue/watch_test.c b/samples/watch_queue/watch_test.c
index f792c13614f4..0018ecac188a 100644
--- a/samples/watch_queue/watch_test.c
+++ b/samples/watch_queue/watch_test.c
@@ -30,6 +30,12 @@
#ifndef __NR_watch_devices
#define __NR_watch_devices -1
#endif
+#ifndef __NR_watch_mount
+#define __NR_watch_mount -1
+#endif
+#ifndef __NR_watch_sb
+#define __NR_watch_sb -1
+#endif
#define BUF_SIZE 4
@@ -61,6 +67,47 @@ static void saw_key_change(struct watch_notification *n)
k->key_id, n->subtype, key_subtypes[n->subtype], k->aux);
}
+static const char *mount_subtypes[256] = {
+ [NOTIFY_MOUNT_NEW_MOUNT] = "new_mount",
+ [NOTIFY_MOUNT_UNMOUNT] = "unmount",
+ [NOTIFY_MOUNT_EXPIRY] = "expiry",
+ [NOTIFY_MOUNT_READONLY] = "readonly",
+ [NOTIFY_MOUNT_SETATTR] = "setattr",
+ [NOTIFY_MOUNT_MOVE_FROM] = "move_from",
+ [NOTIFY_MOUNT_MOVE_TO] = "move_to",
+};
+
+static void saw_mount_change(struct watch_notification *n)
+{
+ struct mount_notification *m = (struct mount_notification *)n;
+ unsigned int len = (n->info & WATCH_INFO_LENGTH) >> WATCH_INFO_LENGTH__SHIFT;
+
+ if (len != sizeof(struct mount_notification) / WATCH_LENGTH_GRANULARITY)
+ return;
+
+ printf("MOUNT %08x change=%u[%s] aux=%u\n",
+ m->triggered_on, n->subtype, mount_subtypes[n->subtype], m->changed_mount);
+}
+
+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)
+{
+ struct superblock_notification *s = (struct superblock_notification *)n;
+ unsigned int len = (n->info & WATCH_INFO_LENGTH) >> WATCH_INFO_LENGTH__SHIFT;
+
+ if (len < sizeof(struct superblock_notification) / WATCH_LENGTH_GRANULARITY)
+ return;
+
+ printf("SUPER %08llx change=%u[%s]\n",
+ s->sb_id, n->subtype, super_subtypes[n->subtype]);
+}
+
static const char *block_subtypes[256] = {
[NOTIFY_BLOCK_ERROR_TIMEOUT] = "timeout",
[NOTIFY_BLOCK_ERROR_NO_SPACE] = "critical space allocation",
@@ -159,6 +206,12 @@ static int consumer(int fd, struct watch_queue_buffer *buf)
case WATCH_TYPE_USB_NOTIFY:
saw_usb_event(n);
break;
+ case WATCH_TYPE_MOUNT_NOTIFY:
+ saw_mount_change(n);
+ break;
+ case WATCH_TYPE_SB_NOTIFY:
+ saw_super_change(n);
+ break;
}
tail += (n->info & WATCH_INFO_LENGTH) >> WATCH_INFO_LENGTH__SHIFT;
@@ -186,6 +239,19 @@ static struct watch_notification_filter filter = {
.type = WATCH_TYPE_USB_NOTIFY,
.subtype_filter[0] = UINT_MAX,
},
+ [3] = {
+ .type = WATCH_TYPE_MOUNT_NOTIFY,
+ // Reject move-from notifications
+ .subtype_filter[0] = UINT_MAX & ~(1 << NOTIFY_MOUNT_MOVE_FROM),
+ },
+ [4] = {
+ .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,
+ },
},
};
@@ -229,5 +295,15 @@ int main(int argc, char **argv)
exit(1);
}
+ if (syscall(__NR_watch_mount, AT_FDCWD, "/", 0, fd, 0x02) == -1) {
+ perror("watch_mount");
+ exit(1);
+ }
+
+ if (syscall(__NR_watch_sb, AT_FDCWD, "/mnt", 0, fd, 0x03) == -1) {
+ perror("watch_sb");
+ exit(1);
+ }
+
return consumer(fd, buf);
}
next prev parent reply other threads:[~2019-06-28 15:51 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-28 15:50 [PATCH 0/6] Mount and superblock notifications [ver #5] David Howells
2019-06-28 15:50 ` [PATCH 1/6] security: Add hooks to rule on setting a superblock or mount watch " David Howells
2019-07-12 20:11 ` James Morris
2019-06-28 15:50 ` [PATCH 2/6] Adjust watch_queue documentation to mention mount and superblock watches. " David Howells
2019-07-01 2:59 ` Randy Dunlap
2019-07-01 8:52 ` David Howells
2019-07-01 14:52 ` Randy Dunlap
2019-06-28 15:50 ` [PATCH 3/6] vfs: Add a mount-notification facility " David Howells
2019-06-28 15:50 ` [PATCH 4/6] vfs: Add superblock notifications " David Howells
2019-06-28 15:51 ` [PATCH 5/6] fsinfo: Export superblock notification counter " David Howells
2019-06-28 15:51 ` David Howells [this message]
2019-06-28 16:47 ` [PATCH 0/6] Mount and superblock notifications " David Howells
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