add hotplug support to the driver core for devices, if their bus type supports it.

diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index f609ddee181ea4725ce69983476f0f15a5f80114..a3e459cc1f6e75b7e306400f477c3066ab082fe4 100644 (file)
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -6,6 +6,8 @@ obj-y           := core.o sys.o interface.o power.o bus.o \
 
 obj-y          += fs/
 
+obj-$(CONFIG_HOTPLUG)  += hotplug.o
+
 export-objs    := core.o power.o sys.o bus.o driver.o \
                        class.o intf.o platform.o cpu.o 
 

diff --git a/drivers/base/base.h b/drivers/base/base.h
index b6a3f3ec145ca8966f238964ccd68b0a3e47a40d..0c05ae058971cc4ab0b275610091d7279a4b62ef 100644 (file)
--- a/drivers/base/base.h
+++ b/drivers/base/base.h
@@ -50,3 +50,13 @@ extern void interface_remove(struct device_class *, struct device *);
 
 extern int driver_attach(struct device_driver * drv);
 extern void driver_detach(struct device_driver * drv);
+
+#ifdef CONFIG_HOTPLUG
+extern int dev_hotplug(struct device *dev, const char *action);
+#else
+static inline int dev_hotplug(struct device *dev, const char *action)
+{
+       return 0;
+}
+#endif
+

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 1d0cb0d0b0362c074635f4f16429dd7f71794b66..9b958256c1bbf3d6e6c2ffdb3021c4be03ed67d0 100644 (file)
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -200,6 +200,9 @@ int device_register(struct device *dev)
        if (platform_notify)
                platform_notify(dev);
 
+       /* notify userspace of device entry */
+       dev_hotplug(dev, "add");
+
  register_done:
        if (error) {
                spin_lock(&device_lock);
@@ -255,6 +258,9 @@ void put_device(struct device * dev)
        if (platform_notify_remove)
                platform_notify_remove(dev);
 
+       /* notify userspace that this device is about to disappear */
+       dev_hotplug (dev, "remove");
+
        device_detach(dev);
        bus_remove_device(dev);
 

diff --git a/drivers/base/hotplug.c b/drivers/base/hotplug.c
new file mode 100644 (file)
index 0000000..231d42c
--- /dev/null
+++ b/drivers/base/hotplug.c
@@ -0,0 +1,103 @@
+/*
+ * drivers/base/hotplug.c - hotplug call code
+ * 
+ * Copyright (c) 2000-2001 David Brownell
+ * Copyright (c) 2002 Greg Kroah-Hartman
+ * Copyright (c) 2002 IBM Corp.
+ *
+ * Based off of drivers/usb/core/usb.c:call_agent(), which was 
+ * written by David Brownell.
+ *
+ */
+
+#define DEBUG 0
+
+#include <linux/device.h>
+#include <linux/slab.h>
+#include <linux/err.h>
+#include <linux/kmod.h>
+#include <linux/interrupt.h>
+#include "base.h"
+
+/*
+ * hotplugging invokes what /proc/sys/kernel/hotplug says (normally
+ * /sbin/hotplug) when devices get added or removed.
+ *
+ * This invokes a user mode policy agent, typically helping to load driver
+ * or other modules, configure the device, and more.  Drivers can provide
+ * a MODULE_DEVICE_TABLE to help with module loading subtasks.
+ */
+#define BUFFER_SIZE    1024    /* should be enough memory for the env */
+#define NUM_ENVP       32      /* number of env pointers */
+int dev_hotplug (struct device *dev, const char *action)
+{
+       char *argv [3], **envp, *buffer, *scratch;
+       int retval;
+       int i = 0;
+
+       pr_debug ("%s\n", __FUNCTION__);
+       if (!dev)
+               return -ENODEV;
+
+       if (!dev->bus || !dev->bus->hotplug)
+               return -ENODEV;
+
+       if (!hotplug_path [0])
+               return -ENODEV;
+
+       if (in_interrupt ()) {
+               pr_debug ("%s - in_interrupt, not allowed!", __FUNCTION__);
+               return -EIO;
+       }
+
+       if (!current->fs->root) {
+               /* don't try to do anything unless we have a root partition */
+               pr_debug ("%s - %s -- no FS yet\n", __FUNCTION__, action);
+               return -EIO;
+       }
+
+       envp = (char **) kmalloc (NUM_ENVP * sizeof (char *), GFP_KERNEL);
+       if (!envp)
+               return -ENOMEM;
+
+       buffer = kmalloc (BUFFER_SIZE, GFP_KERNEL);
+       if (!buffer) {
+               kfree (envp);
+               return -ENOMEM;
+       }
+
+       /* only one standardized param to hotplug command: the bus name */
+       argv [0] = hotplug_path;
+       argv [1] = dev->bus->name;
+       argv [2] = 0;
+
+       /* minimal command environment */
+       envp [i++] = "HOME=/";
+       envp [i++] = "PATH=/sbin:/bin:/usr/sbin:/usr/bin";
+
+       scratch = buffer;
+
+       /* action:  add, remove */
+       envp [i++] = scratch;
+       scratch += sprintf (scratch, "ACTION=%s", action) + 1;
+
+       /* have the bus specific function set up the rest of the environment */
+       retval = dev->bus->hotplug (dev, &envp[i], NUM_ENVP - i,
+                                   scratch, BUFFER_SIZE - (scratch - buffer));
+       if (retval) {
+               pr_debug ("%s - hotplug() returned %d\n", __FUNCTION__, retval);
+               goto exit;
+       }
+
+       pr_debug ("%s: %s %s %s %s %s %s\n", __FUNCTION__, argv [0], argv[1],
+                 action, envp[0], envp[1], envp[2]);
+       retval = call_usermodehelper (argv [0], argv, envp);
+       if (retval)
+               pr_debug ("%s - call_usermodehelper returned %d\n",
+                         __FUNCTION__, retval);
+
+exit:
+       kfree (buffer);
+       kfree (envp);
+       return retval;
+}

diff --git a/include/linux/device.h b/include/linux/device.h
index 6053349e4303d833f7d74eb9f46fd5825726f3da..ef76b15fa93063c3d6fc33c936f0f683f89fc0ff 100644 (file)
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -67,6 +67,8 @@ struct bus_type {
 
        int             (*match)(struct device * dev, struct device_driver * drv);
        struct device * (*add)  (struct device * parent, char * bus_id);
+       int             (*hotplug) (struct device *dev, char **envp, 
+                                   int num_envp, char *buffer, int buffer_size);
 };