[PATCH v1 07/12] netoops: Add user programmable fields to the netoops packet.

[Mike Waychison <mikew@google.com>]

In our environment, it is important for us to capture motherboard name,
firmware version and boot number for consideration when analyzing netoops
dumps.

We collect this information in userland at system startup (in platform specific
ways) and plug this information into the netoops driver via files available in
sysfs.

Files introduced:
  /sys/kernel/netdump/netdump_board_name
  /sys/kernel/netdump/netdump_fw_version
  /sys/kernel/netdump/netdump_boot_id

If this were to be rewritten, we would probably like to have a more general way
for userland to add to netdump packets.

Signed-off-by: Mike Waychison <mikew@google.com>
---
TODO: This would probably be better handled by havin the kernel accept some blob
of data.  It doesn't need to know what the data itself is, as long as it is
delivered in each packet.
---
 drivers/net/netoops.c |   89 ++++++++++++++++++++++++++++++++++++++++++++++---
 1 files changed, 84 insertions(+), 5 deletions(-)

diff --git a/drivers/net/netoops.c b/drivers/net/netoops.c
index 0865212..13c4d51 100644
--- a/drivers/net/netoops.c
+++ b/drivers/net/netoops.c
@@ -54,7 +54,7 @@ struct netoops_msg {
 		u16 type;
 		u32 packet_count;
 		u32 packet_no;
-		u32 __reserved1;
+		u32 blog_boot_id;
 		u8 x86_family;
 		u8 x86_model;
 		u8 x86_stepping;
@@ -63,8 +63,13 @@ struct netoops_msg {
 		 * termination not required.
 		 */
 		char kernel_version[64];
-		char __reserved2[64];
-		char __reserved3[64];
+		/*
+		 * bios and board info come from smbios which
+		 * has a maximum string length of 64 according
+		 * to page 26 of the smbios 2.3 spec.
+		 */
+		char bios_version[64];
+		char motherboard_type[64];
 		/* NOTE: regs is 60 or 168 bytes */
 		struct pt_regs regs; /* arch specific. */
 		/*
@@ -82,6 +87,10 @@ static struct neighbour *netoops_neighbour;
 static DEFINE_SPINLOCK(netoops_lock);
 static struct netoops_msg msg;
 
+static char netoops_fw_version[80];
+static char netoops_board_name[80];
+static int netoops_boot_number;
+
 static void save_and_disable_netoops(struct net_device *dev);
 static void restore_netoops(struct net_device *dev);
 
@@ -320,11 +329,16 @@ static void setup_packet_header(int packet_count, struct pt_regs *regs,
 	msg.header.dump_id = (jiffies/HZ) & 0xffff;
 	msg.header.packet_count = packet_count;
 	msg.header.header_size = sizeof(msg.header);
+	msg.header.blog_boot_id = (u32)netoops_boot_number;
 #ifndef CONFIG_UML
 	msg.header.x86_family = current_cpu_data.x86;
 	msg.header.x86_model = current_cpu_data.x86_model;
 	msg.header.x86_stepping = current_cpu_data.x86_mask;
 #endif
+	strncpy(msg.header.bios_version, netoops_fw_version,
+		sizeof(msg.header.bios_version));
+	strncpy(msg.header.motherboard_type, netoops_board_name,
+		sizeof(msg.header.motherboard_type));
 	strncpy(msg.header.kernel_version,
 		utsname()->release,
 		min(sizeof(msg.header.kernel_version),
@@ -431,6 +445,60 @@ static void netoops(struct kmsg_dumper *dumper, enum kmsg_dump_reason reason,
 	spin_unlock(&netoops_lock);
 }
 
+static ssize_t netoops_show(struct kobject *kobj,
+			    struct kobj_attribute *attr,
+			    char *buf) {
+
+	if (!strcmp(attr->attr.name, "netdump_fw_version"))
+		strncpy(buf, netoops_fw_version, PAGE_SIZE);
+	else if (!strcmp(attr->attr.name, "netdump_board_name"))
+		strncpy(buf, netoops_board_name, PAGE_SIZE);
+	else if (!strcmp(attr->attr.name, "netdump_boot_number"))
+		snprintf(buf, PAGE_SIZE, "%d\n", netoops_boot_number);
+	buf[PAGE_SIZE - 1] = '\0';
+	return strnlen(buf, PAGE_SIZE);
+}
+
+static ssize_t netoops_store(struct kobject *kobj,
+			     struct kobj_attribute *attr,
+			     const char *buf,
+			     size_t count) {
+	if (!count)
+		return count;
+
+	if (!strcmp(attr->attr.name, "netdump_fw_version")) {
+		strncpy(netoops_fw_version, buf, sizeof(netoops_fw_version));
+		netoops_fw_version[sizeof(netoops_fw_version) - 1] = '\0';
+	} else if (!strcmp(attr->attr.name, "netdump_board_name")) {
+		strncpy(netoops_board_name, buf, sizeof(netoops_board_name));
+		netoops_board_name[sizeof(netoops_board_name) - 1] = '\0';
+	} else if (!strcmp(attr->attr.name, "netdump_boot_number")) {
+		((char *)buf)[count - 1] = '\0';
+		sscanf(buf, "%du", &netoops_boot_number);
+	}
+	return count;
+}
+
+static struct kobj_attribute netoops_fw_version_attribute =
+	__ATTR(netoops_fw_version, 0666, netoops_show, netoops_store);
+static struct kobj_attribute netoops_board_name_attribute =
+	__ATTR(netoops_board_name, 0666, netoops_show, netoops_store);
+static struct kobj_attribute netoops_boot_number_attribute =
+	__ATTR(netoops_boot_number, 0666, netoops_show, netoops_store);
+
+static struct attribute *attrs[] = {
+	&netoops_fw_version_attribute.attr,
+	&netoops_board_name_attribute.attr,
+	&netoops_boot_number_attribute.attr,
+	NULL,
+};
+
+static struct attribute_group attr_group = {
+	.attrs = attrs,
+};
+
+static struct kobject *netoops_kobj;
+
 static struct kmsg_dumper netoops_dumper = {
 	.dump = netoops,
 };
@@ -530,9 +598,15 @@ static int __init netoops_init(void)
 	BUILD_BUG_ON(offsetof(struct netoops_msg, header.version) != 0);
 	BUILD_BUG_ON(offsetof(struct netoops_msg, header.dump_id) != 6);
 
+	netoops_kobj = kobject_create_and_add("netdump", kernel_kobj);
+	if (!netoops_kobj)
+		return -ENOMEM;
+	retval = sysfs_create_group(netoops_kobj, &attr_group);
+	if (retval)
+		goto cleanup_kobj;
 	retval = kmsg_dump_register(&netoops_dumper);
 	if (retval)
-		goto out;
+		goto cleanup_sysfs_group;
 
 	/* Register hooks */
 	retval = register_netdevice_notifier(&netoops_notifier);
@@ -550,7 +624,10 @@ cleanup_netdevice:
 	unregister_netdevice_notifier(&netoops_notifier);
 cleanup_kmsg_dump:
 	kmsg_dump_unregister(&netoops_dumper);
-out:
+cleanup_sysfs_group:
+	sysfs_remove_group(netoops_kobj, &attr_group);
+cleanup_kobj:
+	kobject_put(netoops_kobj);
 	return retval;
 }
 
@@ -560,6 +637,8 @@ static void __exit netoops_exit(void)
 	unregister_netdevice_notifier(&netoops_notifier);
 	disable_netoops();
 	kmsg_dump_unregister(&netoops_dumper);
+	sysfs_remove_group(netoops_kobj, &attr_group);
+	kobject_put(netoops_kobj);
 }
 
 module_init(netoops_init);