This patch adds support for communicating with a userspace helper via a
netlink socket. It is used by the userspace user interface support and
by the storage manager support.
Signed-off-by: Nigel Cunningham <nigel@xxxxxxxxxxxx>
---
kernel/power/Makefile | 4 +
kernel/power/tuxonice_netlink.c | 339 +++++++++++++++++++++++++++++++++++++++
2 files changed, 343 insertions(+), 0 deletions(-)
create mode 100644 kernel/power/tuxonice_netlink.c
diff --git a/kernel/power/Makefile b/kernel/power/Makefile
index 07efc8a..180b89a 100644
--- a/kernel/power/Makefile
+++ b/kernel/power/Makefile
@@ -10,6 +10,10 @@ tuxonice_core-objs := tuxonice_modules.o tuxonice_sysfs.o tuxonice_highlevel.o \
obj-$(CONFIG_TOI) += tuxonice_builtin.o
+ifdef CONFIG_NET
+tuxonice_core-objs += tuxonice_netlink.o
+endif
+
obj-$(CONFIG_TOI_CORE) += tuxonice_core.o
obj-$(CONFIG_PM) += main.o
diff --git a/kernel/power/tuxonice_netlink.c b/kernel/power/tuxonice_netlink.c
new file mode 100644
index 0000000..c394f79
--- /dev/null
+++ b/kernel/power/tuxonice_netlink.c
@@ -0,0 +1,339 @@
+/*
+ * kernel/power/tuxonice_netlink.c
+ *
+ * Copyright (C) 2004-2008 Nigel Cunningham (nigel at tuxonice net)
+ *
+ * This file is released under the GPLv2.
+ *
+ * Functions for communicating with a userspace helper via netlink.
+ */
+
+
+#include <linux/suspend.h>
+#include "tuxonice_netlink.h"
+#include "tuxonice.h"
+#include "tuxonice_modules.h"
+#include "tuxonice_alloc.h"
+
+static struct user_helper_data *uhd_list;
+
+/*
+ * Refill our pool of SKBs for use in emergencies (eg, when eating memory and
+ * none can be allocated).
+ */
+static void toi_fill_skb_pool(struct user_helper_data *uhd)
+{
+ while (uhd->pool_level < uhd->pool_limit) {
+ struct sk_buff *new_skb =
+ alloc_skb(NLMSG_SPACE(uhd->skb_size), TOI_ATOMIC_GFP);
+
+ if (!new_skb)
+ break;
+
+ new_skb->next = uhd->emerg_skbs;
+ uhd->emerg_skbs = new_skb;
+ uhd->pool_level++;
+ }
+}
+
+/*
+ * Try to allocate a single skb. If we can't get one, try to use one from
+ * our pool.
+ */
+static struct sk_buff *toi_get_skb(struct user_helper_data *uhd)
+{
+ struct sk_buff *skb =
+ alloc_skb(NLMSG_SPACE(uhd->skb_size), TOI_ATOMIC_GFP);
+
+ if (skb)
+ return skb;
+
+ skb = uhd->emerg_skbs;
+ if (skb) {
+ uhd->pool_level--;
+ uhd->emerg_skbs = skb->next;
+ skb->next = NULL;
+ }
+
+ return skb;
+}
+
+static void put_skb(struct user_helper_data *uhd, struct sk_buff *skb)
+{
+ if (uhd->pool_level < uhd->pool_limit) {
+ skb->next = uhd->emerg_skbs;
+ uhd->emerg_skbs = skb;
+ } else
+ kfree_skb(skb);
+}
+
+void toi_send_netlink_message(struct user_helper_data *uhd,
+ int type, void *params, size_t len)
+{
+ struct sk_buff *skb;
+ struct nlmsghdr *nlh;
+ void *dest;
+ struct task_struct *t;
+
+ if (uhd->pid == -1)
+ return;
+
+ if (uhd->debug)
+ printk(KERN_ERR "toi_send_netlink_message: Send "
+ "message type %d.\n", type);
+
+ skb = toi_get_skb(uhd);
+ if (!skb) {
+ printk(KERN_INFO "toi_netlink: Can't allocate skb!\n");
+ return;
+ }
+
+ /* NLMSG_PUT contains a hidden goto nlmsg_failure */
+ nlh = NLMSG_PUT(skb, 0, uhd->sock_seq, type, len);
+ uhd->sock_seq++;
+
+ dest = NLMSG_DATA(nlh);
+ if (params && len > 0)
+ memcpy(dest, params, len);
+
+ netlink_unicast(uhd->nl, skb, uhd->pid, 0);
+
+ read_lock(&tasklist_lock);
+ t = find_task_by_pid_type_ns(PIDTYPE_PID, uhd->pid, &init_pid_ns);
+ if (!t) {
+ read_unlock(&tasklist_lock);
+ if (uhd->pid > -1)
+ printk(KERN_INFO "Hmm. Can't find the userspace task"
+ " %d.\n", uhd->pid);
+ return;
+ }
+ wake_up_process(t);
+ read_unlock(&tasklist_lock);
+
+ yield();
+
+ return;
+
+nlmsg_failure:
+ if (skb)
+ put_skb(uhd, skb);
+
+ if (uhd->debug)
+ printk(KERN_ERR "toi_send_netlink_message: Failed to send "
+ "message type %d.\n", type);
+}
+
+static void send_whether_debugging(struct user_helper_data *uhd)
+{
+ static u8 is_debugging = 1;
+
+ toi_send_netlink_message(uhd, NETLINK_MSG_IS_DEBUGGING,
+ &is_debugging, sizeof(u8));
+}
+
+/*
+ * Set the PF_NOFREEZE flag on the given process to ensure it can run whilst we
+ * are hibernating.
+ */
+static int nl_set_nofreeze(struct user_helper_data *uhd, __u32 pid)
+{
+ struct task_struct *t;
+
+ if (uhd->debug)
+ printk(KERN_ERR "nl_set_nofreeze for pid %d.\n", pid);
+
+ read_lock(&tasklist_lock);
+ t = find_task_by_pid_type_ns(PIDTYPE_PID, pid, &init_pid_ns);
+ if (!t) {
+ read_unlock(&tasklist_lock);
+ printk(KERN_INFO "Strange. Can't find the userspace task %d.\n",
+ pid);
+ return -EINVAL;
+ }
+
+ t->flags |= PF_NOFREEZE;
+
+ read_unlock(&tasklist_lock);
+ uhd->pid = pid;
+
+ toi_send_netlink_message(uhd, NETLINK_MSG_NOFREEZE_ACK, NULL, 0);
+
+ return 0;
+}
+
+/*
+ * Called when the userspace process has informed us that it's ready to roll.
+ */
+static int nl_ready(struct user_helper_data *uhd, u32 version)
+{
+ if (version != uhd->interface_version) {
+ printk(KERN_INFO "%s userspace process using invalid interface"
+ " version (%d - kernel wants %d). Trying to "
+ "continue without it.\n",
+ uhd->name, version, uhd->interface_version);
+ if (uhd->not_ready)
+ uhd->not_ready();
+ return -EINVAL;
+ }
+
+ complete(&uhd->wait_for_process);
+
+ return 0;
+}
+
+void toi_netlink_close_complete(struct user_helper_data *uhd)
+{
+ if (uhd->nl) {
+ netlink_kernel_release(uhd->nl);
+ uhd->nl = NULL;
+ }
+
+ while (uhd->emerg_skbs) {
+ struct sk_buff *next = uhd->emerg_skbs->next;
+ kfree_skb(uhd->emerg_skbs);
+ uhd->emerg_skbs = next;
+ }
+
+ uhd->pid = -1;
+}
+
+static int toi_nl_gen_rcv_msg(struct user_helper_data *uhd,
+ struct sk_buff *skb, struct nlmsghdr *nlh)
+{
+ int type = nlh->nlmsg_type;
+ int *data;
+ int err;
+
+ if (uhd->debug)
+ printk(KERN_ERR "toi_user_rcv_skb: Received message %d.\n",
+ type);
+
+ /* Let the more specific handler go first. It returns
+ * 1 for valid messages that it doesn't know. */
+ err = uhd->rcv_msg(skb, nlh);
+ if (err != 1)
+ return err;
+
+ /* Only allow one task to receive NOFREEZE privileges */
+ if (type == NETLINK_MSG_NOFREEZE_ME && uhd->pid != -1) {
+ printk(KERN_INFO "Received extra nofreeze me requests.\n");
+ return -EBUSY;
+ }
+
+ data = NLMSG_DATA(nlh);
+
+ switch (type) {
+ case NETLINK_MSG_NOFREEZE_ME:
+ return nl_set_nofreeze(uhd, nlh->nlmsg_pid);
+ case NETLINK_MSG_GET_DEBUGGING:
+ send_whether_debugging(uhd);
+ return 0;
+ case NETLINK_MSG_READY:
+ if (nlh->nlmsg_len != NLMSG_LENGTH(sizeof(u32))) {
+ printk(KERN_INFO "Invalid ready mesage.\n");
+ if (uhd->not_ready)
+ uhd->not_ready();
+ return -EINVAL;
+ }
+ return nl_ready(uhd, (u32) *data);
+ case NETLINK_MSG_CLEANUP:
+ toi_netlink_close_complete(uhd);
+ return 0;
+ }
+
+ return -EINVAL;
+}
+
+static void toi_user_rcv_skb(struct sk_buff *skb)
+{
+ int err;
+ struct nlmsghdr *nlh;
+ struct user_helper_data *uhd = uhd_list;
+
+ while (uhd && uhd->netlink_id != skb->sk->sk_protocol)
+ uhd = uhd->next;
+
+ if (!uhd)
+ return;
+
+ while (skb->len >= NLMSG_SPACE(0)) {
+ u32 rlen;
+
+ nlh = (struct nlmsghdr *) skb->data;
+ if (nlh->nlmsg_len < sizeof(*nlh) || skb->len < nlh->nlmsg_len)
+ return;
+
+ rlen = NLMSG_ALIGN(nlh->nlmsg_len);
+ if (rlen > skb->len)
+ rlen = skb->len;
+
+ err = toi_nl_gen_rcv_msg(uhd, skb, nlh);
+ if (err)
+ netlink_ack(skb, nlh, err);
+ else if (nlh->nlmsg_flags & NLM_F_ACK)
+ netlink_ack(skb, nlh, 0);
+ skb_pull(skb, rlen);
+ }
+}
+
+static int netlink_prepare(struct user_helper_data *uhd)
+{
+ uhd->next = uhd_list;
+ uhd_list = uhd;
+
+ uhd->sock_seq = 0x42c0ffee;
+ uhd->nl = netlink_kernel_create(&init_net, uhd->netlink_id, 0,
+ toi_user_rcv_skb, NULL, THIS_MODULE);
+ if (!uhd->nl) {
+ printk(KERN_INFO "Failed to allocate netlink socket for %s.\n",
+ uhd->name);
+ return -ENOMEM;
+ }
+
+ toi_fill_skb_pool(uhd);
+
+ return 0;
+}
+
+void toi_netlink_close(struct user_helper_data *uhd)
+{
+ struct task_struct *t;
+
+ read_lock(&tasklist_lock);
+ t = find_task_by_pid_type_ns(PIDTYPE_PID, uhd->pid, &init_pid_ns);
+ if (t)
+ t->flags &= ~PF_NOFREEZE;
+ read_unlock(&tasklist_lock);
+
+ toi_send_netlink_message(uhd, NETLINK_MSG_CLEANUP, NULL, 0);
+}
+
+int toi_netlink_setup(struct user_helper_data *uhd)
+{
+ /* In case userui didn't cleanup properly on us */
+ toi_netlink_close_complete(uhd);
+
+ if (netlink_prepare(uhd) < 0) {
+ printk(KERN_INFO "Netlink prepare failed.\n");
+ return 1;
+ }
+
+ if (toi_launch_userspace_program(uhd->program, uhd->netlink_id,
+ UMH_WAIT_EXEC, uhd->debug) < 0) {
+ printk(KERN_INFO "Launch userspace program failed.\n");
+ toi_netlink_close_complete(uhd);
+ return 1;
+ }
+
+ /* Wait 2 seconds for the userspace process to make contact */
+ wait_for_completion_timeout(&uhd->wait_for_process, 2*HZ);
+
+ if (uhd->pid == -1) {
+ printk(KERN_INFO "%s: Failed to contact userspace process.\n",
+ uhd->name);
+ toi_netlink_close_complete(uhd);
+ return 1;
+ }
+
+ return 0;
+}
--
1.5.6.3
_______________________________________________
linux-pm mailing list
linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx
https://lists.linux-foundation.org/mailman/listinfo/linux-pm
