[PATCH] netlink: decode libudev netlink header

[Harsha Sharma]

* netlink.c: decode family NETLINK_KOBJECT_UEVENT if prefix is libudev
* linux/netlink_kobject_uevent.h: New struct (udev_monitor_netlink_header)

Signed-off-by: Harsha Sharma <harshasharmaiitr at gmail.com>
---
 linux/netlink_kobject_uevent.h | 16 ++++++++++++++++
 netlink.c                      | 27 ++++++++++++++++++++++++++-
 2 files changed, 42 insertions(+), 1 deletion(-)
 create mode 100644 linux/netlink_kobject_uevent.h

diff --git a/linux/netlink_kobject_uevent.h b/linux/netlink_kobject_uevent.h
new file mode 100644
index 00000000..d83ccad5
--- /dev/null
+++ b/linux/netlink_kobject_uevent.h
@@ -0,0 +1,16 @@
+#ifndef STRACE_LINUX_NETLINK_KOBJECT_UEVENT_H
+#define STRACE_LINUX_NETLINK_KOBJECT_UEVENT_H
+
+struct udev_monitor_netlink_header {
+	char prefix[8];
+	unsigned int magic;
+	unsigned int header_size;
+	unsigned int properties_off;
+	unsigned int properties_len;
+	unsigned int filter_subsystem_hash;
+	unsigned int filter_devtype_hash;
+	unsigned int filter_tag_bloom_hi;
+	unsigned int filter_tag_bloom_lo;
+};
+
+#endif /* !STRACE_LINUX_NETLINK_KOBJECT_UEVENT_H */
diff --git a/netlink.c b/netlink.c
index 6b9a1f5c..e991ed86 100644
--- a/netlink.c
+++ b/netlink.c
@@ -32,6 +32,7 @@
 #include "nlattr.h"
 #include <linux/audit.h>
 #include <linux/rtnetlink.h>
+#include <linux/netlink_kobject_uevent.h>
 #include <linux/xfrm.h>
 #include "xlat/netlink_ack_flags.h"
 #include "xlat/netlink_delete_flags.h"
@@ -183,6 +184,29 @@ decode_nlmsg_type_netfilter(const struct xlat *const xlat,
 		tprintf("%#x", msg_type);
 }
 
+static bool
+decode_nlmsg_type_kobject_uevent(struct tcb *tcp, kernel_ulong_t addr,
+				 kernel_ulong_t len,
+				 const void *const opaque_data)
+{
+	struct udev_monitor_netlink_header uh;
+	const char *prefix = "libudev";
+
+	if (len < sizeof(uh))
+		return false;
+	if (!umove_or_printaddr(tcp, addr, &uh) &&
+	    strcmp(uh.prefix, prefix) == 0) {
+		tprintf("{prefix=%s, magic=%u, header_size=%u, properties_off=%u, properties_len=%u, filter_subsystem_hash=%u, filter_devtype_hash=%u, filter_tag_bloom_hi=%u, filter_tag_bloom_lo=%u}", uh.prefix,
+		    uh.magic, uh.header_size, uh.properties_off,
+		    uh.properties_len, uh.filter_subsystem_hash,
+		    uh.filter_devtype_hash, uh.filter_tag_bloom_hi,
+		    uh.filter_tag_bloom_lo);
+		return true;
+	}
+	return false;
+}
+
+
 typedef void (*nlmsg_types_decoder_t)(const struct xlat *,
 				      uint16_t type,
 				      const char *dflt);
@@ -628,7 +652,8 @@ decode_netlink(struct tcb *const tcp,
 	const int family = get_fd_nl_family(tcp, fd);
 
 	if (family == NETLINK_KOBJECT_UEVENT) {
-		printstrn(tcp, addr, len);
+		if (!decode_nlmsg_type_kobject_uevent(tcp, addr, len, NULL))
+			printstrn(tcp, addr, len);
 		return;
 	}
 
-- 
2.11.0