[PATCH 1/2] makedumpfile/eppic: Add README for eppic scripts
Aruna Balakrishnaiah
aruna at linux.vnet.ibm.com
Thu Mar 6 06:06:15 EST 2014
Signed-off-by: Aruna Balakrishnaiah <aruna at linux.vnet.ibm.com>
---
eppic_scripts/README | 294 ++++++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 294 insertions(+)
create mode 100644 eppic_scripts/README
diff --git a/eppic_scripts/README b/eppic_scripts/README
new file mode 100644
index 0000000..040b3ba
--- /dev/null
+++ b/eppic_scripts/README
@@ -0,0 +1,294 @@
+===================================
+ Eppic scripts README
+==================================
+
+The eppic scripts are based on the fedora 19 kernel.
+
+1. Eppic script: proc_names.c
+ Description: Scrubs executable name of each user process
+
+ Explanation:
+ Walks all processes via the tasks lists starting from init_task
+
+ extern struct task_struct init_task;
+
+ struct task_struct {
+ ...
+ struct list_head tasks;
+ ...
+ char comm[TASK_COMM_LEN]; /* executable name excluding path */
+ ...
+ };
+
+ For each user space process clear executable name
+
+ struct task_struct *tsk;
+ list_for_each_entry(tsk, &init_task, tasks) {
+ if (tsk->mm)
+ memset(tsk->comm, 0, TASK_COMM_LEN);
+ }
+
+
+2. Eppic script: dir_names.c
+ Description: Scrubs filenames of cached dentries
+
+ Explanation:
+ i) iterate over all mounted filesystems
+
+ struct vfsmount {
+ struct list_head mnt_hash;
+ ...
+ struct dentry *mnt_root; /* root of the mounted tree */
+ ...
+ };
+
+ for (u = 0; i < HASH_SIZE; u++) {
+ struct vfsmount *mnt;
+ list_for_each_entry(mnt, &mount_hashtable[u], mnt_hash) {
+ struct dentry *root;
+ root = mnt->mnt_root;
+ ...
+ }
+ }
+
+ ii) recursively walk the dentries of each tree starting from root dentry
+ and clear d_name and d_iname
+
+ struct dentry {
+ ...
+ struct qstr d_name;
+ ...
+ unsigned char d_iname[DNAME_INLINE_LEN]; /* small names */
+ ...
+ struct list_head d_subdirs; /* our children */
+ ...
+ };
+
+ void walk_dentries(struct dentry *dentry)
+ {
+ struct dentry *child;
+ memset(dentry->d_iname, 0, DNAME_INLINE_LEN);
+ memset(dentry->d_name.name, 0, dentry->d_name.len);
+ list_for_each_entry(child, &dentry->d_subdirs, d_u.d_child)
+ walk_dentries(child);
+ }
+
+3. Eppic script: keyring.c
+ Description: Scrubs all entries in the keyring
+
+ Explanation:
+ Scan the keyring_name_hash hash table
+
+ static struct list_head keyring_name_hash[KEYRING_NAME_HASH_SIZE];
+
+ for (i = 0; i < KEYRING_NAME_HASH_SIZE; i++)
+ if (!list_empty(&keyring_name_hash[i])) {
+ ...
+ }
+
+ For each non-empty list walk all keyring entries
+
+ struct key {
+ ...
+ struct key_type *type; /* type of key */
+ ...
+ unsigned short datalen; /* payload data length */
+ ...
+ union {
+ struct list_head link;
+ ...
+ } type_data;
+ ...
+ union {
+ unsigned long value;
+ void __rcu *rcudata;
+ void *data;
+ struct keyring_list __rcu *subscriptions;
+ } payload;
+ };
+
+ struct key *key;
+ list_for_each_entry(key, &keyring_name_hash[i], type_data.link) {
+ ...
+ }
+
+ Clear value/rcudata/data dependent on the type of the key.
+
+4. Eppic script: ap_messages.c
+ Description: Clear the message data of all ap_bus requests
+
+ Explanation:
+ Walk all devices in the LIST_HEAD(ap_device_list);
+
+ struct ap_device {
+ ...
+ struct list_head list; /* private list of all AP devices. */
+ ...
+ struct list_head pendingq; /* List of message sent to AP queue. */
+ int pendingq_count; /* # requests on pendingq list. */
+ struct list_head requestq; /* List of message yet to be sent. */
+ int requestq_count; /* # requests on requestq list. */
+ ...
+ };
+
+ struct ap_device *device;
+ list_for_each_entry(device, &ap_device_list, list) {
+ ...
+ }
+
+ For each ap device walk the pendingq and requestq list
+
+ struct ap_message {
+ struct list_head list; /* Request queueing. */
+ ...
+ void *message; /* Pointer to message buffer. */
+ size_t length; /* Message length. */
+ ...
+ };
+
+ struct ap_message *apmsg;
+ list_for_each_entry(apmsg, &device->pendingq, list) {
+ ...
+ }
+ list_for_each_entry(apmsg, &device->requestq, list) {
+ ...
+ }
+
+ For each message in pendingq and requestq clear the message
+
+ memset(apmsg->message, 0, apmsg->length);
+
+5. Eppic script: tcp_sk_buf.c
+ Description: Scrub data in tcp socket buffers
+
+ Explanation:
+ Find tcp domain sockets (struct sock *sk)
+
+ tcp sockets:
+
+ Iterate from 0 to INET_LHTABLE_SIZE and get inet_list_hashbucket from
+ tcp_hash_info.listening_hash[<index>]
+
+ for (i = 0; i < INET_LHTABLE_SIZE; i++) {
+ struct inet_listen_hashbucket *ilb = &tcp_hashinfo.listening_hash[i];
+ }
+ For each hash bucket iterate over ilb->head null list to get sockets:
+ struct sock *sk;
+ sk_nulls_for_each(sk, node, &ilb->head) {
+ ...
+ }
+
+
+ For each socket iterate over the socket buffers in
+ sk_receive_queue and sk_write_queue:
+
+ struct sock {
+ ...
+ struct sk_buff_head sk_receive_queue;
+ ...
+ struct sk_buff_head sk_write_queue;
+ ...
+ };
+
+ struct sk_buff_head {
+ struct sk_buff *next;
+ struct sk_buff *prev;
+ };
+
+ For each struct sk_buff in the two lists clear the memory referenced
+ by skb->data / skb->data_len:
+
+ struct sk_buff {
+ ...
+ unsigned int data_len;
+ ...
+ unsigned char *data;
+ ...
+ };
+
+6. Eppic script: udp_sk_buf.c
+ Description: Scrub data of udp socket buffers
+
+ Explanation:
+ Find all udp sockets (struct sock *sk)
+
+ udp sockets:
+
+ Iterate from 0 to udp_table->mask and get udp_hslot from hash table:
+ for (i = 0; i < udp->table->mask; i++) {
+ struct udp_hslot *hslot = udp_table->hash[i];
+ ...
+ }
+
+ For each hslot iterate over hslot->head null list to get sockets:
+ struct sock *sk;
+ sk_nulls_for_each(sk, node, &hslot->head) {
+ ...
+ }
+
+ For each socket iterate over the socket buffers in
+ sk_receive_queue and sk_write_queue.
+
+ For each struct sk_buff in the two lists clear the memory referenced
+ by skb->data / skb->data_len.
+
+7. Eppic script: unix_sk_buf.c
+ Description: Scrub data of unix socket buffers
+
+ Explanation:
+ Iterate from 0 to UNIX_HASH_SIZE and then walk the hlist in
+ for (i = 0; i < UNIX_HASH_SIZE; i++) {
+ struct list_head *list = &unix_socket_table[i];
+ ...
+ }
+
+ Walk each non-empty list in unix_socket_table
+ struct sock *sk;
+ sk_for_each(sk, node, &unix_socket_table[i])
+
+ For each socket iterate over the socket buffers in
+ sk_receive_queue and sk_write_queue.
+
+ For each struct sk_buff in the two lists clear the memory referenced
+ by skb->data / skb->data_len.
+
+8. Eppic script: vhost_net_buffers.c
+ Description: Scrub socket buffers of guest network I/O
+
+ Explanation:
+ Scrub socket buffers of guest network I/O
+
+ vhost_net instance will be attached to the file's private data.
+ To get to the right file check the fdtable for each task, if the file
+ has registered its fops with vhost_net_open, if so we can retreive the
+ file's private data.
+
+ if (task->files->fdt->fd[i]->f_op->open == &vhost_net_open)
+ struct vhost_net *net = f->private_data;
+
+ struct vhost_net_virtqueue *nvq = &net->vqs[VHOST_NET_VQ_MAX];
+ struct vhost_virtqueue *vq = &nvq->vq;
+ struct socket *sock = vq->private_data;
+ struct sock *sk = sock->sk;
+
+ struct sk_buff *next = sk->sk_receive_queue.next;
+ struct sk_buff *prev = sk->sk_receive_queue.prev;
+
+ Scrub next->data till the end of the sk_receive_queue and
+ sk_write_queue list
+
+
+9. Eppic script: vhost_scsi_buffers.c
+ Description: Scrub buffers involved in guest block I/O
+
+ Explanation:
+ vhost_scsi instance will be attached to the file's private data.
+ to get to the right file check the fdtable for each task, if the
+ file has registered its fops with vhost_net_open, if so we can
+ retreive the file's private data.
+
+ if (task->files->fdt->fd[i]->f_op->open == &vhost_scsi_open)
+ vhost_scsi *vs = task->files->fdt->fd[i]->private_data;
+
+ struct vhost_virtqueue *vq = (struct vhost_virtqueue *)vs->vqs[i].vq;
+ scrub vq->iov[j].iov_base
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