diff options
author | Kay Sievers <kay.sievers@vrfy.org> | 2004-10-31 21:06:02 -0800 |
---|---|---|
committer | Greg Kroah-Hartman <greg@kroah.com> | 2004-10-31 21:06:02 -0800 |
commit | a6391b5b189187af9f47c473ec9ffc515d05536e (patch) | |
tree | f51c052450d3f4ce9b2bae6dc9058fa0c6b163c6 /lib | |
parent | cb5f226ec57ec664ea08efa515daa5eea3bdd69c (diff) | |
download | history-a6391b5b189187af9f47c473ec9ffc515d05536e.tar.gz |
[PATCH] kobject: fix hotplug bug with seqnum
On Sat, Oct 30, 2004 at 04:54:29AM +0200, Kay Sievers wrote:
> On Sat, Oct 30, 2004 at 02:25:23AM +0200, Kay Sievers wrote:
> > On Sat, Oct 30, 2004 at 02:00:45AM +0200, Kay Sievers wrote:
> > > On Fri, Oct 29, 2004 at 06:13:19PM -0500, Greg KH wrote:
> > > > On Fri, Oct 29, 2004 at 11:28:56PM +0200, Kay Sievers wrote:
> > > > > > But there might still be a problem. With this change, the sequence
> > > > > > number is not sent out the kevent message. Kay, do you think this is an
> > > > > > issue? I don't think we can get netlink messages out of order, right?
> > > > >
> > > > > Right, especially not the events with the same DEVPATH, like "remove"
> > > > > beating an "add". But I'm not sure if the number isn't useful. Whatever
> > > > > we may do with the hotplug over netlink in the future, we will only have
> > > > > /sbin/hotplug for the early boot and it may be nice to know, what events
> > > > > we have already handled...
> > > > >
> > > > > > I'll hold off on applying this patch until we figure this out...
> > > > >
> > > > > How about just reserving 20 bytes for the number (u64 will never be
> > > > > more than that), save the pointer to that field, and fill the number in
> > > > > later?
> > > >
> > > > Ah, something like this instead? I like it, it's even smaller than the
> > > > previous patch. Compile tested only...
> > >
> > > I like that. How about the following. It will keep the buffer clean from
> > > random chars, cause the kevent does not have the vector and relies on
> > > the '\0' to separate the strings from each other.
> > > I've tested it. The netlink-hotplug message looks like this:
> > >
> > > recv(3, "remove@/class/input/mouse2\0ACTION=remove\0DEVPATH=/class/input/mouse2\0SUBSYSTEM=input\0SEQNUM=961 \0", 1024, 0) = 113
> >
> > Hmm, these trailing spaces are just bad, sorry. I'll better pass the
> > envp array over to send_uevent() and clean up the keys while copying
> > the env values into the skb buffer. This will make the event payload
> > more safe too. So your first version looks better.
>
> How about this? We copy over key by key into the skb buffer and the
> netlink message can get the envp array without depending on a single
> continuous buffer.
>
> The netlink message looks nice like this now:
>
> recv(3, "
> add@/devices/pci0000:00/0000:00:1d.1/usb3/3-2/3-2:1.0\0
> HOME=/\0
> PATH=/sbin:/bin:/usr/sbin:/usr/bin\0
> ACTION=add\0
> DEVPATH=/devices/pci0000:00/0000:00:1d.1/usb3/3-2/3-2:1.0\0
> SUBSYSTEM=usb\0
> SEQNUM=991\0
> DEVICE=/proc/bus/usb/003/008\0
> PRODUCT=46d/c03e/2000\0
> TYPE=0/0/0\0
> INTERFACE=3/1/2\0
> ", 1024, 0) = 268
Here is an improved version that uses skb_put() to fill the skb buffer,
instead of trimming the buffer to the final size after we've copied over
all keys.
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
Diffstat (limited to 'lib')
-rw-r--r-- | lib/kobject_uevent.c | 47 |
1 files changed, 30 insertions, 17 deletions
diff --git a/lib/kobject_uevent.c b/lib/kobject_uevent.c index 41380e9c5d32b2..f352f37704199e 100644 --- a/lib/kobject_uevent.c +++ b/lib/kobject_uevent.c @@ -23,6 +23,9 @@ #include <linux/kobject.h> #include <net/sock.h> +#define BUFFER_SIZE 1024 /* buffer for the hotplug env */ +#define NUM_ENVP 32 /* number of env pointers */ + #if defined(CONFIG_KOBJECT_UEVENT) || defined(CONFIG_HOTPLUG) static char *action_to_string(enum kobject_action action) { @@ -53,12 +56,11 @@ static struct sock *uevent_sock; * * @signal: signal name * @obj: object path (kobject) - * @buf: buffer used to pass auxiliary data like the hotplug environment - * @buflen: - * gfp_mask: + * @envp: possible hotplug environment to pass with the message + * @gfp_mask: */ -static int send_uevent(const char *signal, const char *obj, const void *buf, - int buflen, int gfp_mask) +static int send_uevent(const char *signal, const char *obj, + char **envp, int gfp_mask) { struct sk_buff *skb; char *pos; @@ -69,16 +71,25 @@ static int send_uevent(const char *signal, const char *obj, const void *buf, len = strlen(signal) + 1; len += strlen(obj) + 1; - len += buflen; - skb = alloc_skb(len, gfp_mask); + /* allocate buffer with the maximum possible message size */ + skb = alloc_skb(len + BUFFER_SIZE, gfp_mask); if (!skb) return -ENOMEM; pos = skb_put(skb, len); + sprintf(pos, "%s@%s", signal, obj); + + /* copy the environment key by key to our continuous buffer */ + if (envp) { + int i; - pos += sprintf(pos, "%s@%s", signal, obj) + 1; - memcpy(pos, buf, buflen); + for (i = 2; envp[i]; i++) { + len = strlen(envp[i]) + 1; + pos = skb_put(skb, len); + strcpy(pos, envp[i]); + } + } return netlink_broadcast(uevent_sock, skb, 0, 1, gfp_mask); } @@ -107,10 +118,10 @@ static int do_kobject_uevent(struct kobject *kobj, enum kobject_action action, if (!attrpath) goto exit; sprintf(attrpath, "%s/%s", path, attr->name); - rc = send_uevent(signal, attrpath, NULL, 0, gfp_mask); + rc = send_uevent(signal, attrpath, NULL, gfp_mask); kfree(attrpath); } else { - rc = send_uevent(signal, path, NULL, 0, gfp_mask); + rc = send_uevent(signal, path, NULL, gfp_mask); } exit: @@ -169,8 +180,6 @@ static inline int send_uevent(const char *signal, const char *obj, u64 hotplug_seqnum; static spinlock_t sequence_lock = SPIN_LOCK_UNLOCKED; -#define BUFFER_SIZE 1024 /* should be enough memory for the env */ -#define NUM_ENVP 32 /* number of env pointers */ /** * kobject_hotplug - notify userspace by executing /sbin/hotplug * @@ -182,6 +191,7 @@ void kobject_hotplug(struct kobject *kobj, enum kobject_action action) char *argv [3]; char **envp = NULL; char *buffer = NULL; + char *seq_buff; char *scratch; int i = 0; int retval; @@ -258,6 +268,11 @@ void kobject_hotplug(struct kobject *kobj, enum kobject_action action) envp [i++] = scratch; scratch += sprintf(scratch, "SUBSYSTEM=%s", name) + 1; + /* reserve space for the sequence, + * put the real one in after the hotplug call */ + envp[i++] = seq_buff = scratch; + scratch += strlen("SEQNUM=18446744073709551616") + 1; + if (hotplug_ops->hotplug) { /* have the kset specific function add its stuff */ retval = hotplug_ops->hotplug (kset, kobj, @@ -273,15 +288,13 @@ void kobject_hotplug(struct kobject *kobj, enum kobject_action action) spin_lock(&sequence_lock); seq = ++hotplug_seqnum; spin_unlock(&sequence_lock); - - envp [i++] = scratch; - scratch += sprintf(scratch, "SEQNUM=%lld", (long long)seq) + 1; + sprintf(seq_buff, "SEQNUM=%lld", (long long)seq); pr_debug ("%s: %s %s seq=%lld %s %s %s %s %s\n", __FUNCTION__, argv[0], argv[1], (long long)seq, envp[0], envp[1], envp[2], envp[3], envp[4]); - send_uevent(action_string, kobj_path, buffer, scratch - buffer, GFP_KERNEL); + send_uevent(action_string, kobj_path, envp, GFP_KERNEL); if (!hotplug_path[0]) goto exit; |