From 16574dccd8f62dc1b585325f8a6a0aab10047ed8 Mon Sep 17 00:00:00 2001 From: Kay Sievers Date: Fri, 6 Apr 2007 01:40:38 +0200 Subject: [PATCH 1/1] Driver core: make uevent-environment available in uevent-file This allows sysfs to show the environment variables that are available if the uevent happens. This lets userspace not have to cache all of this information as the kernel already knows it. Signed-off-by: Kay Sievers Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 50 ++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 49 insertions(+), 1 deletion(-) diff --git a/drivers/base/core.c b/drivers/base/core.c index c34a4d8842e..72c6ee57471 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -246,6 +246,53 @@ static struct kset_uevent_ops device_uevent_ops = { .uevent = dev_uevent, }; +static ssize_t show_uevent(struct device *dev, struct device_attribute *attr, + char *buf) +{ + struct kobject *top_kobj; + struct kset *kset; + char *envp[32]; + char data[PAGE_SIZE]; + char *pos; + int i; + size_t count = 0; + int retval; + + /* search the kset, the device belongs to */ + top_kobj = &dev->kobj; + if (!top_kobj->kset && top_kobj->parent) { + do { + top_kobj = top_kobj->parent; + } while (!top_kobj->kset && top_kobj->parent); + } + if (!top_kobj->kset) + goto out; + kset = top_kobj->kset; + if (!kset->uevent_ops || !kset->uevent_ops->uevent) + goto out; + + /* respect filter */ + if (kset->uevent_ops && kset->uevent_ops->filter) + if (!kset->uevent_ops->filter(kset, &dev->kobj)) + goto out; + + /* let the kset specific function add its keys */ + pos = data; + retval = kset->uevent_ops->uevent(kset, &dev->kobj, + envp, ARRAY_SIZE(envp), + pos, PAGE_SIZE); + if (retval) + goto out; + + /* copy keys to file */ + for (i = 0; envp[i]; i++) { + pos = &buf[count]; + count += sprintf(pos, "%s\n", envp[i]); + } +out: + return count; +} + static ssize_t store_uevent(struct device *dev, struct device_attribute *attr, const char *buf, size_t count) { @@ -621,10 +668,11 @@ int device_add(struct device *dev) BUS_NOTIFY_ADD_DEVICE, dev); dev->uevent_attr.attr.name = "uevent"; - dev->uevent_attr.attr.mode = S_IWUSR; + dev->uevent_attr.attr.mode = S_IRUGO | S_IWUSR; if (dev->driver) dev->uevent_attr.attr.owner = dev->driver->owner; dev->uevent_attr.store = store_uevent; + dev->uevent_attr.show = show_uevent; error = device_create_file(dev, &dev->uevent_attr); if (error) goto attrError; -- 2.41.1