Re: D-BUS patch for udev-008

[David Zeuthen <david@fubar.dk>]

On Mon, 2003-12-08 at 20:40, Greg KH wrote:
> On Mon, Dec 08, 2003 at 12:01:01AM +0100, David Zeuthen wrote:
> > Hi,
> > 
> > Attached is a patch against udev-008 to send out a D-BUS message when a
> > device node is added or removed.
> 
> Very nice.  I've applied your patch, and then made the following
> changes:
> 	- fixed the formatting to use tabs instead of spaces
> 	- removed all of the #ifdef USE_DBUS statments out of the code
> 	  (I've been writing kernel code too long, #ifdef within .c
> 	  files looks ugly to me...) and created a new file udev_dbus.c
> 	  to hold these functions.
> 	- changed the Makefile variable to DBUS instead of USE_DBUS
> 	- turned the default option to not build the DBUS support as I
> 	  can't get it to link properly on a number of different OSs.
> 

Many thanks for this.

> 
> How did you test this?  I get lots of errors at link time using a Fedora
> 1 machine.  And I can't even build DBUS on an old Red Hat 7.3 box due to
> automake issues :(
> 

I'm using Fedora 1 with D-BUS from CVS installed in /usr/local. I do get
a few message from the linker because of static linking, see below, but
it does link. What's the reason for linking statically?

Btw, Fedora 1 ships with D-BUS 0.13 which is way different from D-BUS in
CVS, so you might need to set PKG_CONFIG_PATH to point to the correct
dbus-1.pc and install udev_sysbus_policy.conf into the proper location.

Oh, and even though you have done this, you might still link with the
old D-BUS because I made a mistake in the Makefile. You need to change

  LIB_OBJS += $(shell pkg-config --libs-only-l dbus-1)

to something like

  LDFLAGS += $(shell pkg-config --libs dbus-1)

yes? (I was tweaking the Makefile quite a lot myself; sorry about that)

I've also found a problem with my patch: There's an issue where when two
instances of udev is running at the same time (processing /block/sda and
/block/sda/sda1 when plugging in usb-storage). 

One of the copies become a secondary owner of the org.kernel.udev
service and this means that the emitted D-BUS signal doesn't appear to
come from the owner of that service as I thought it would. I'm not sure
if this is the intended behavior of D-BUS, it might be.. 

The only reason it works in python is that, uhm, the python bindings are
a bit broken. It only works in C if you ignore filtering on service
owner.

Cheers,
David


[david@laptop udev-008]$ touch udev.c
[david@laptop udev-008]$ make
gcc -pipe -Wall -Wshadow -Wstrict-prototypes -Wmissing-prototypes
-Wmissing-declarations -Os -fomit-frame-pointer -D_GNU_SOURCE
-I/usr/lib/gcc-lib/i386-redhat-linux/3.3.2/include -DUSE_DBUS
-I/usr/local/include/dbus-1.0 -I/usr/local/lib/dbus-1.0/include     -c
-o udev.o udev.c
udev.c:75: warning: function declaration isn't a prototype
udev.c:85: warning: function declaration isn't a prototype
gcc --static  -o udev  udev.o udev_config.o udev-add.o udev-remove.o
udevdb.o logging.o namedev.o namedev_parse.o libsysfs/sysfs_bus.o
libsysfs/sysfs_class.o libsysfs/sysfs_device.o libsysfs/sysfs_dir.o
libsysfs/sysfs_driver.o libsysfs/sysfs_utils.o libsysfs/dlist.o
tdb/tdb.o tdb/spinlock.o -lc -ldbus-1
udev-add.o(.text+0x30d): In function `create_node':
: warning: Using 'getgrnam' in statically linked applications requires
at runtime the shared libraries from the glibc version used for linking
udev-add.o(.text+0x2cb): In function `create_node':
: warning: Using 'getpwnam' in statically linked applications requires
at runtime the shared libraries from the glibc version used for linking
/usr/local/lib/libdbus-1.a(dbus-sysdeps.o)(.text+0x14e0): In function
`fill_user_info':
/home/david/xdg-hacking/dbus/dbus/dbus-sysdeps.c:1504: warning: Using
'getgrouplist' in statically linked applications requires at runtime the
shared libraries from the glibc version used for linking
/usr/local/lib/libdbus-1.a(dbus-sysdeps.o)(.text+0x1482):/home/david/xdg-hacking/dbus/dbus/dbus-sysdeps.c:1467: warning: Using 'getpwuid' in statically linked applications requires at runtime the shared libraries from the glibc version used for linking
/usr/local/lib/libdbus-1.a(dbus-sysdeps.o)(.text+0x6e3): In function
`_dbus_connect_tcp_socket':
/home/david/xdg-hacking/dbus/dbus/dbus-sysdeps.c:617: warning: Using
'gethostbyname' in statically linked applications requires at runtime
the shared libraries from the glibc version used for linking
strip -s --remove-section=.note --remove-section=.comment udev





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