/****************************************************************************** * Talks to Xen Store to figure out what devices we have. * * Copyright (C) 2005 Rusty Russell, IBM Corporation * Copyright (C) 2005 Mike Wray, Hewlett-Packard * Copyright (C) 2005, 2006 XenSource Ltd * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation; or, when distributed * separately from the Linux kernel or incorporated into other * software packages, subject to the following license: * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this source file (the "Software"), to deal in the Software without * restriction, including without limitation the rights to use, copy, modify, * merge, publish, distribute, sublicense, and/or sell copies of the Software, * and to permit persons to whom the Software is furnished to do so, subject to * the following conditions: * * The above copyright notice and this permission notice shall be included in * all copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS * IN THE SOFTWARE. */ #define DPRINTK(fmt, args...) \ pr_debug("xenbus_probe (%s:%d) " fmt ".\n", \ __func__, __LINE__, ##args) #include <linux/kernel.h> #include <linux/err.h> #include <linux/string.h> #include <linux/ctype.h> #include <linux/fcntl.h> #include <linux/mm.h> #include <linux/proc_fs.h> #include <linux/notifier.h> #include <linux/kthread.h> #include <linux/mutex.h> #include <linux/io.h> #include <asm/page.h> #include <asm/pgtable.h> #include <asm/xen/hypervisor.h> #include <xen/xenbus.h> #include <xen/events.h> #include <xen/page.h> #include "xenbus_comms.h" #include "xenbus_probe.h" int xen_store_evtchn; EXPORT_SYMBOL(xen_store_evtchn); struct xenstore_domain_interface *xen_store_interface; static unsigned long xen_store_mfn; static BLOCKING_NOTIFIER_HEAD(xenstore_chain); static void wait_for_devices(struct xenbus_driver *xendrv); static int xenbus_probe_frontend(const char *type, const char *name); static void xenbus_dev_shutdown(struct device *_dev); static int xenbus_dev_suspend(struct device *dev, pm_message_t state); static int xenbus_dev_resume(struct device *dev); /* If something in array of ids matches this device, return it. */ static const struct xenbus_device_id * match_device(const struct xenbus_device_id *arr, struct xenbus_device *dev) { for (; *arr->devicetype != '\0'; arr++) { if (!strcmp(arr->devicetype, dev->devicetype)) return arr; } return NULL; } int xenbus_match(struct device *_dev, struct device_driver *_drv) { struct xenbus_driver *drv = to_xenbus_driver(_drv); if (!drv->ids) return 0; return match_device(drv->ids, to_xenbus_device(_dev)) != NULL; } static int xenbus_uevent(struct device *_dev, struct kobj_uevent_env *env) { struct xenbus_device *dev = to_xenbus_device(_dev); if (add_uevent_var(env, "MODALIAS=xen:%s", dev->devicetype)) return -ENOMEM; return 0; } /* device/<type>/<id> => <type>-<id> */ static int frontend_bus_id(char bus_id[XEN_BUS_ID_SIZE], const char *nodename) { nodename = strchr(nodename, '/'); if (!nodename || strlen(nodename + 1) >= XEN_BUS_ID_SIZE) { printk(KERN_WARNING "XENBUS: bad frontend %s\n", nodename); return -EINVAL; } strlcpy(bus_id, nodename + 1, XEN_BUS_ID_SIZE); if (!strchr(bus_id, '/')) { printk(KERN_WARNING "XENBUS: bus_id %s no slash\n", bus_id); return -EINVAL; } *strchr(bus_id, '/') = '-'; return 0; } static void free_otherend_details(struct xenbus_device *dev) { kfree(dev->otherend); dev->otherend = NULL; } static void free_otherend_watch(struct xenbus_device *dev) { if (dev->otherend_watch.node) { unregister_xenbus_watch(&dev->otherend_watch); kfree(dev->otherend_watch.node); dev->otherend_watch.node = NULL; } } int read_otherend_details(struct xenbus_device *xendev, char *id_node, char *path_node) { int err = xenbus_gather(XBT_NIL, xendev->nodename, id_node, "%i", &xendev->otherend_id, path_node, NULL, &xendev->otherend, NULL); if (err) { xenbus_dev_fatal(xendev, err, "reading other end details from %s", xendev->nodename); return err; } if (strlen(xendev->otherend) == 0 || !xenbus_exists(XBT_NIL, xendev->otherend, "")) { xenbus_dev_fatal(xendev, -ENOENT, "unable to read other end from %s. " "missing or inaccessible.", xendev->nodename); free_otherend_details(xendev); return -ENOENT; } return 0; } static int read_backend_details(struct xenbus_device *xendev) { return read_otherend_details(xendev, "backend-id", "backend"); } static struct device_attribute xenbus_dev_attrs[] = { __ATTR_NULL }; /* Bus type for frontend drivers. */ static struct xen_bus_type xenbus_frontend = { .root = "device", .levels = 2, /* device/type/<id> */ .get_bus_id = frontend_bus_id, .probe = xenbus_probe_frontend, .bus = { .name = "xen", .match = xenbus_match, .uevent = xenbus_uevent, .probe = xenbus_dev_probe, .remove = xenbus_dev_remove, .shutdown = xenbus_dev_shutdown, .dev_attrs = xenbus_dev_attrs, .suspend = xenbus_dev_suspend, .resume = xenbus_dev_resume, }, }; static void otherend_changed(struct xenbus_watch *watch, const char **vec, unsigned int len) { struct xenbus_device *dev = container_of(watch, struct xenbus_device, otherend_watch); struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver); enum xenbus_state state; /* Protect us against watches firing on old details when the otherend details change, say immediately after a resume. */ if (!dev->otherend || strncmp(dev->otherend, vec[XS_WATCH_PATH], strlen(dev->otherend))) { dev_dbg(&dev->dev, "Ignoring watch at %s\n", vec[XS_WATCH_PATH]); return; } state = xenbus_read_driver_state(dev->otherend); dev_dbg(&dev->dev, "state is %d, (%s), %s, %s\n", state, xenbus_strstate(state), dev->otherend_watch.node, vec[XS_WATCH_PATH]); /* * Ignore xenbus transitions during shutdown. This prevents us doing * work that can fail e.g., when the rootfs is gone. */ if (system_state > SYSTEM_RUNNING) { struct xen_bus_type *bus = bus; bus = container_of(dev->dev.bus, struct xen_bus_type, bus); /* If we're frontend, drive the state machine to Closed. */ /* This should cause the backend to release our resources. */ if ((bus == &xenbus_frontend) && (state == XenbusStateClosing)) xenbus_frontend_closed(dev); return; } if (drv->otherend_changed) drv->otherend_changed(dev, state); } static int talk_to_otherend(struct xenbus_device *dev) { struct xenbus_driver *drv = to_xenbus_driver(dev->dev.driver); free_otherend_watch(dev); free_otherend_details(dev); return drv->read_otherend_details(dev); } static int watch_otherend(struct xenbus_device *dev) { return xenbus_watch_pathfmt(dev, &dev->otherend_watch, otherend_changed, "%s/%s", dev->otherend, "state"); } int xenbus_dev_probe(struct device *_dev) { struct xenbus_device *dev = to_xenbus_device(_dev); struct xenbus_driver *drv = to_xenbus_driver(_dev->driver); const struct xenbus_device_id *id; int err; DPRINTK("%s", dev->nodename); if (!drv->probe) { err = -ENODEV; goto fail; } id = match_device(drv->ids, dev); if (!id) { err = -ENODEV; goto fail; } err = talk_to_otherend(dev); if (err) { dev_warn(&dev->dev, "talk_to_otherend on %s failed.\n", dev->nodename); return err; } err = drv->probe(dev, id); if (err) goto fail; err = watch_otherend(dev); if (err) { dev_warn(&dev->dev, "watch_otherend on %s failed.\n", dev->nodename); return err; } return 0; fail: xenbus_dev_error(dev, err, "xenbus_dev_probe on %s", dev->nodename); xenbus_switch_state(dev, XenbusStateClosed); return -ENODEV; } int xenbus_dev_remove(struct device *_dev) { struct xenbus_device *dev = to_xenbus_device(_dev); struct xenbus_driver *drv = to_xenbus_driver(_dev->driver); DPRINTK("%s", dev->nodename); free_otherend_watch(dev); free_otherend_details(dev); if (drv->remove) drv->remove(dev); xenbus_switch_state(dev, XenbusStateClosed); return 0; } static void xenbus_dev_shutdown(struct device *_dev) { struct xenbus_device *dev = to_xenbus_device(_dev); unsigned long timeout = 5*HZ; DPRINTK("%s", dev->nodename); get_device(&dev->dev); if (dev->state != XenbusStateConnected) { printk(KERN_INFO "%s: %s: %s != Connected, skipping\n", __func__, dev->nodename, xenbus_strstate(dev->state)); goto out; } xenbus_switch_state(dev, XenbusStateClosing); timeout = wait_for_completion_timeout(&dev->down, timeout); if (!timeout) printk(KERN_INFO "%s: %s timeout closing device\n", __func__, dev->nodename); out: put_device(&dev->dev); } int xenbus_register_driver_common(struct xenbus_driver *drv, struct xen_bus_type *bus, struct module *owner, const char *mod_name) { drv->driver.name = drv->name; drv->driver.bus = &bus->bus; drv->driver.owner = owner; drv->driver.mod_name = mod_name; return driver_register(&drv->driver); } int __xenbus_register_frontend(struct xenbus_driver *drv, struct module *owner, const char *mod_name) { int ret; drv->read_otherend_details = read_backend_details; ret = xenbus_register_driver_common(drv, &xenbus_frontend, owner, mod_name); if (ret) return ret; /* If this driver is loaded as a module wait for devices to attach. */ wait_for_devices(drv); return 0; } EXPORT_SYMBOL_GPL(__xenbus_register_frontend); void xenbus_unregister_driver(struct xenbus_driver *drv) { driver_unregister(&drv->driver); } EXPORT_SYMBOL_GPL(xenbus_unregister_driver); struct xb_find_info { struct xenbus_device *dev; const char *nodename; }; static int cmp_dev(struct device *dev, void *data) { struct xenbus_device *xendev = to_xenbus_device(dev); struct xb_find_info *info = data; if (!strcmp(xendev->nodename, info->nodename)) { info->dev = xendev; get_device(dev); return 1; } return 0; } struct xenbus_device *xenbus_device_find(const char *nodename, struct bus_type *bus) { struct xb_find_info info = { .dev = NULL, .nodename = nodename }; bus_for_each_dev(bus, NULL, &info, cmp_dev); return info.dev; } static int cleanup_dev(struct device *dev, void *data) { struct xenbus_device *xendev = to_xenbus_device(dev); struct xb_find_info *info = data; int len = strlen(info->nodename); DPRINTK("%s", info->nodename); /* Match the info->nodename path, or any subdirectory of that path. */ if (strncmp(xendev->nodename, info->nodename, len)) return 0; /* If the node name is longer, ensure it really is a subdirectory. */ if ((strlen(xendev->nodename) > len) && (xendev->nodename[len] != '/')) return 0; info->dev = xendev; get_device(dev); return 1; } static void xenbus_cleanup_devices(const char *path, struct bus_type *bus) { struct xb_find_info info = { .nodename = path }; do { info.dev = NULL; bus_for_each_dev(bus, NULL, &info, cleanup_dev); if (info.dev) { device_unregister(&info.dev->dev); put_device(&info.dev->dev); } } while (info.dev); } static void xenbus_dev_release(struct device *dev) { if (dev) kfree(to_xenbus_device(dev)); } static ssize_t xendev_show_nodename(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "%s\n", to_xenbus_device(dev)->nodename); } DEVICE_ATTR(nodename, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_nodename, NULL); static ssize_t xendev_show_devtype(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "%s\n", to_xenbus_device(dev)->devicetype); } DEVICE_ATTR(devtype, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_devtype, NULL); static ssize_t xendev_show_modalias(struct device *dev, struct device_attribute *attr, char *buf) { return sprintf(buf, "xen:%s\n", to_xenbus_device(dev)->devicetype); } DEVICE_ATTR(modalias, S_IRUSR | S_IRGRP | S_IROTH, xendev_show_modalias, NULL); int xenbus_probe_node(struct xen_bus_type *bus, const char *type, const char *nodename) { char devname[XEN_BUS_ID_SIZE]; int err; struct xenbus_device *xendev; size_t stringlen; char *tmpstring; enum xenbus_state state = xenbus_read_driver_state(nodename); if (state != XenbusStateInitialising) { /* Device is not new, so ignore it. This can happen if a device is going away after switching to Closed. */ return 0; } stringlen = strlen(nodename) + 1 + strlen(type) + 1; xendev = kzalloc(sizeof(*xendev) + stringlen, GFP_KERNEL); if (!xendev) return -ENOMEM; xendev->state = XenbusStateInitialising; /* Copy the strings into the extra space. */ tmpstring = (char *)(xendev + 1); strcpy(tmpstring, nodename); xendev->nodename = tmpstring; tmpstring += strlen(tmpstring) + 1; strcpy(tmpstring, type); xendev->devicetype = tmpstring; init_completion(&xendev->down); xendev->dev.bus = &bus->bus; xendev->dev.release = xenbus_dev_release; err = bus->get_bus_id(devname, xendev->nodename); if (err) goto fail; dev_set_name(&xendev->dev, devname); /* Register with generic device framework. */ err = device_register(&xendev->dev); if (err) goto fail; err = device_create_file(&xendev->dev, &dev_attr_nodename); if (err) goto fail_unregister; err = device_create_file(&xendev->dev, &dev_attr_devtype); if (err) goto fail_remove_nodename; err = device_create_file(&xendev->dev, &dev_attr_modalias); if (err) goto fail_remove_devtype; return 0; fail_remove_devtype: device_remove_file(&xendev->dev, &dev_attr_devtype); fail_remove_nodename: device_remove_file(&xendev->dev, &dev_attr_nodename); fail_unregister: device_unregister(&xendev->dev); fail: kfree(xendev); return err; } /* device/<typename>/<name> */ static int xenbus_probe_frontend(const char *type, const char *name) { char *nodename; int err; nodename = kasprintf(GFP_KERNEL, "%s/%s/%s", xenbus_frontend.root, type, name); if (!nodename) return -ENOMEM; DPRINTK("%s", nodename); err = xenbus_probe_node(&xenbus_frontend, type, nodename); kfree(nodename); return err; } static int xenbus_probe_device_type(struct xen_bus_type *bus, const char *type) { int err = 0; char **dir; unsigned int dir_n = 0; int i; dir = xenbus_directory(XBT_NIL, bus->root, type, &dir_n); if (IS_ERR(dir)) return PTR_ERR(dir); for (i = 0; i < dir_n; i++) { err = bus->probe(type, dir[i]); if (err) break; } kfree(dir); return err; } int xenbus_probe_devices(struct xen_bus_type *bus) { int err = 0; char **dir; unsigned int i, dir_n; dir = xenbus_directory(XBT_NIL, bus->root, "", &dir_n); if (IS_ERR(dir)) return PTR_ERR(dir); for (i = 0; i < dir_n; i++) { err = xenbus_probe_device_type(bus, dir[i]); if (err) break; } kfree(dir); return err; } static unsigned int char_count(const char *str, char c) { unsigned int i, ret = 0; for (i = 0; str[i]; i++) if (str[i] == c) ret++; return ret; } static int strsep_len(const char *str, char c, unsigned int len) { unsigned int i; for (i = 0; str[i]; i++) if (str[i] == c) { if (len == 0) return i; len--; } return (len == 0) ? i : -ERANGE; } void xenbus_dev_changed(const char *node, struct xen_bus_type *bus) { int exists, rootlen; struct xenbus_device *dev; char type[XEN_BUS_ID_SIZE]; const char *p, *root; if (char_count(node, '/') < 2) return; exists = xenbus_exists(XBT_NIL, node, ""); if (!exists) { xenbus_cleanup_devices(node, &bus->bus); return; } /* backend/<type>/... or device/<type>/... */ p = strchr(node, '/') + 1; snprintf(type, XEN_BUS_ID_SIZE, "%.*s", (int)strcspn(p, "/"), p); type[XEN_BUS_ID_SIZE-1] = '\0'; rootlen = strsep_len(node, '/', bus->levels); if (rootlen < 0) return; root = kasprintf(GFP_KERNEL, "%.*s", rootlen, node); if (!root) return; dev = xenbus_device_find(root, &bus->bus); if (!dev) xenbus_probe_node(bus, type, root); else put_device(&dev->dev); kfree(root); } EXPORT_SYMBOL_GPL(xenbus_dev_changed); static void frontend_changed(struct xenbus_watch *watch, const char **vec, unsigned int len) { DPRINTK(""); xenbus_dev_changed(vec[XS_WATCH_PATH], &xenbus_frontend); } /* We watch for devices appearing and vanishing. */ static struct xenbus_watch fe_watch = { .node = "device", .callback = frontend_changed, }; static int xenbus_dev_suspend(struct device *dev, pm_message_t state) { int err = 0; struct xenbus_driver *drv; struct xenbus_device *xdev; DPRINTK(""); if (dev->driver == NULL) return 0; drv = to_xenbus_driver(dev->driver); xdev = container_of(dev, struct xenbus_device, dev); if (drv->suspend) err = drv->suspend(xdev, state); if (err) printk(KERN_WARNING "xenbus: suspend %s failed: %i\n", dev_name(dev), err); return 0; } static int xenbus_dev_resume(struct device *dev) { int err; struct xenbus_driver *drv; struct xenbus_device *xdev; DPRINTK(""); if (dev->driver == NULL) return 0; drv = to_xenbus_driver(dev->driver); xdev = container_of(dev, struct xenbus_device, dev); err = talk_to_otherend(xdev); if (err) { printk(KERN_WARNING "xenbus: resume (talk_to_otherend) %s failed: %i\n", dev_name(dev), err); return err; } xdev->state = XenbusStateInitialising; if (drv->resume) { err = drv->resume(xdev); if (err) { printk(KERN_WARNING "xenbus: resume %s failed: %i\n", dev_name(dev), err); return err; } } err = watch_otherend(xdev); if (err) { printk(KERN_WARNING "xenbus_probe: resume (watch_otherend) %s failed: " "%d.\n", dev_name(dev), err); return err; } return 0; } /* A flag to determine if xenstored is 'ready' (i.e. has started) */ int xenstored_ready = 0; int register_xenstore_notifier(struct notifier_block *nb) { int ret = 0; if (xenstored_ready > 0) ret = nb->notifier_call(nb, 0, NULL); else blocking_notifier_chain_register(&xenstore_chain, nb); return ret; } EXPORT_SYMBOL_GPL(register_xenstore_notifier); void unregister_xenstore_notifier(struct notifier_block *nb) { blocking_notifier_chain_unregister(&xenstore_chain, nb); } EXPORT_SYMBOL_GPL(unregister_xenstore_notifier); void xenbus_probe(struct work_struct *unused) { BUG_ON((xenstored_ready <= 0)); /* Enumerate devices in xenstore and watch for changes. */ xenbus_probe_devices(&xenbus_frontend); register_xenbus_watch(&fe_watch); xenbus_backend_probe_and_watch(); /* Notify others that xenstore is up */ blocking_notifier_call_chain(&xenstore_chain, 0, NULL); } static int __init xenbus_probe_init(void) { int err = 0; DPRINTK(""); err = -ENODEV; if (!xen_domain()) goto out_error; /* Register ourselves with the kernel bus subsystem */ err = bus_register(&xenbus_frontend.bus); if (err) goto out_error; err = xenbus_backend_bus_register(); if (err) goto out_unreg_front; /* * Domain0 doesn't have a store_evtchn or store_mfn yet. */ if (xen_initial_domain()) { /* dom0 not yet supported */ } else { xenstored_ready = 1; xen_store_evtchn = xen_start_info->store_evtchn; xen_store_mfn = xen_start_info->store_mfn; } xen_store_interface = mfn_to_virt(xen_store_mfn); /* Initialize the interface to xenstore. */ err = xs_init(); if (err) { printk(KERN_WARNING "XENBUS: Error initializing xenstore comms: %i\n", err); goto out_unreg_back; } if (!xen_initial_domain()) xenbus_probe(NULL); #ifdef CONFIG_XEN_COMPAT_XENFS /* * Create xenfs mountpoint in /proc for compatibility with * utilities that expect to find "xenbus" under "/proc/xen". */ proc_mkdir("xen", NULL); #endif return 0; out_unreg_back: xenbus_backend_bus_unregister(); out_unreg_front: bus_unregister(&xenbus_frontend.bus); out_error: return err; } postcore_initcall(xenbus_probe_init); MODULE_LICENSE("GPL"); static int is_disconnected_device(struct device *dev, void *data) { struct xenbus_device *xendev = to_xenbus_device(dev); struct device_driver *drv = data; struct xenbus_driver *xendrv; /* * A device with no driver will never connect. We care only about * devices which should currently be in the process of connecting. */ if (!dev->driver) return 0; /* Is this search limited to a particular driver? */ if (drv && (dev->driver != drv)) return 0; xendrv = to_xenbus_driver(dev->driver); return (xendev->state != XenbusStateConnected || (xendrv->is_ready && !xendrv->is_ready(xendev))); } static int exists_disconnected_device(struct device_driver *drv) { return bus_for_each_dev(&xenbus_frontend.bus, NULL, drv, is_disconnected_device); } static int print_device_status(struct device *dev, void *data) { struct xenbus_device *xendev = to_xenbus_device(dev); struct device_driver *drv = data; /* Is this operation limited to a particular driver? */ if (drv && (dev->driver != drv)) return 0; if (!dev->driver) { /* Information only: is this too noisy? */ printk(KERN_INFO "XENBUS: Device with no driver: %s\n", xendev->nodename); } else if (xendev->state != XenbusStateConnected) { printk(KERN_WARNING "XENBUS: Timeout connecting " "to device: %s (state %d)\n", xendev->nodename, xendev->state); } return 0; } /* We only wait for device setup after most initcalls have run. */ static int ready_to_wait_for_devices; /* * On a 10 second timeout, wait for all devices currently configured. We need * to do this to guarantee that the filesystems and / or network devices * needed for boot are available, before we can allow the boot to proceed. * * This needs to be on a late_initcall, to happen after the frontend device * drivers have been initialised, but before the root fs is mounted. * * A possible improvement here would be to have the tools add a per-device * flag to the store entry, indicating whether it is needed at boot time. * This would allow people who knew what they were doing to accelerate their * boot slightly, but of course needs tools or manual intervention to set up * those flags correctly. */ static void wait_for_devices(struct xenbus_driver *xendrv) { unsigned long timeout = jiffies + 10*HZ; struct device_driver *drv = xendrv ? &xendrv->driver : NULL; if (!ready_to_wait_for_devices || !xen_domain()) return; while (exists_disconnected_device(drv)) { if (time_after(jiffies, timeout)) break; schedule_timeout_interruptible(HZ/10); } bus_for_each_dev(&xenbus_frontend.bus, NULL, drv, print_device_status); } #ifndef MODULE static int __init boot_wait_for_devices(void) { ready_to_wait_for_devices = 1; wait_for_devices(NULL); return 0; } late_initcall(boot_wait_for_devices); #endif