[PATCH] finally solve the bad sysfs-timing for all of us

On Tue, Sep 21, 2004 at 07:17:34PM +0200, Kay Sievers wrote:
> During the integration of HAL into the linux hotplug system, we dicover
> every week a new signaling path that fails cause of the delayed
> population of the sysfs files, which are connected by symlinks and
> appear in something like a random order in userspace.
>
> It's pretty complicated to understand the connection between all these
> files for all the different subsystems with all the exceptions, so most
> of the users simply sleep a few seconds, but that is not acceptable for
> our integration work.
>
> Here I try to get all the special knowledge about that behavior together
> and place that in a simple binary. That program _must_ run first of all
> other hotplug processsing and every later script, udev or HAL all can get
> rid of the wild guesses about the right time sysfs is ready.
>
> It will not only wait for the "dev"-file events we handle with udev, also
> for every /device-device with the corresponding bus link.
>
> It is provided as a patch against the current udev tree and a "install" will
> place the new program in the hotplug.d directory:
>
>   [kay@pim ~]$ tree /etc/hotplug.d/
>   /etc/hotplug.d/
>   `-- default
>       |-- 00-wait_for_sysfs.hotplug -> /sbin/wait_for_sysfs
>       |-- 10-udev.hotplug -> /sbin/udevsend
>       |-- 20-hal.hotplug -> /usr/libexec/hal.hotplug
>       |-- default.hotplug
>       `-- log.hotplug
>
>
> For now, it logs the result of the waiting to syslog, to catch any
> device, that needs special treatment. All newly discovered delay problems,
> device black/whitelist updates should go into that program and we may remove
> that kind of specialisation from all the other hotplug programs.
>
> Any patches, reports, testing is more than welcome.
>
> Sample debug:
>   Sep 21 18:44:07 localhost kernel: usb 3-2: new full speed USB device using address 12
>   Sep 21 18:44:07 localhost kernel: hub 3-2:1.0: USB hub found
>   Sep 21 18:44:07 localhost kernel: hub 3-2:1.0: 2 ports detected
>   Sep 21 18:44:07 localhost 00-wait_for_sysfs.hotplug: result: waiting for sysfs successful '/devices/pci0000:00/0000:00:1d.1/usb3/3-2'
>   Sep 21 18:44:07 localhost 00-wait_for_sysfs.hotplug: result: waiting for sysfs successful '/devices/pci0000:00/0000:00:1d.1/usb3/3-2/3-2:1.0'
>   Sep 21 18:44:08 localhost kernel: usb 3-2.1: new full speed USB device using address 13
>   Sep 21 18:44:08 localhost 00-wait_for_sysfs.hotplug: result: waiting for sysfs successful '/class/usb/lp0'
>   Sep 21 18:44:08 localhost kernel: drivers/usb/class/usblp.c: usblp0: USB Bidirectional printer dev 13 if 0 alt 1 proto 2 vid 0x067B pid 0x2305
>   Sep 21 18:44:08 localhost 00-wait_for_sysfs.hotplug: result: waiting for sysfs successful '/devices/pci0000:00/0000:00:1d.1/usb3/3-2/3-2.1/3-2.1:1.0'
>   Sep 21 18:44:08 localhost 00-wait_for_sysfs.hotplug: result: waiting for sysfs successful '/devices/pci0000:00/0000:00:1d.1/usb3/3-2/3-2.1'
>   Sep 21 18:44:08 localhost udev: configured rule in '/etc/udev/rules.d/50-udev.rules' at line 29 applied, 'lp0' becomes 'usb/%k'
>   Sep 21 18:44:08 localhost udev: creating device node '/udev/usb/lp0'
>   Sep 21 18:44:09 localhost kernel: usb 3-2.2: new full speed USB device using address 14
>   Sep 21 18:44:09 localhost kernel: pl2303 3-2.2:1.0: PL-2303 converter detected
>   Sep 21 18:44:09 localhost kernel: usb 3-2.2: PL-2303 converter now attached to ttyUSB0
>   Sep 21 18:44:09 localhost 00-wait_for_sysfs.hotplug: result: waiting for sysfs successful '/devices/pci0000:00/0000:00:1d.1/usb3/3-2/3-2.2'
>   Sep 21 18:44:09 localhost 00-wait_for_sysfs.hotplug: result: waiting for sysfs successful '/devices/pci0000:00/0000:00:1d.1/usb3/3-2/3-2.2/3-2.2:1.0'
>   Sep 21 18:44:09 localhost 00-wait_for_sysfs.hotplug: result: waiting for sysfs successful '/devices/pci0000:00/0000:00:1d.1/usb3/3-2/3-2.2/3-2.2:1.0/ttyUSB0'
>   Sep 21 18:44:09 localhost 00-wait_for_sysfs.hotplug: result: waiting for sysfs successful '/class/tty/ttyUSB0'
>   Sep 21 18:44:09 localhost udev: creating device node '/udev/ttyUSB0'

New version with more devices excluded from /device-link saerch and
a better maching for device names.

1 files changed, 12 insertions, 3 deletions

diff --git a/Makefile b/Makefile
index bc2f852614..67a7d46525 100644
--- a/Makefile
+++ b/Makefile
@@ -33,6 +33,7 @@ INFO =		udevinfo
 TESTER =	udevtest
 STARTER =	udevstart
 RULER =		udevruler
+WAIT =		wait_for_sysfs
 VERSION =	032_bk
 INSTALL_DIR =	/usr/local/bin
 RELEASE_NAME =	$(ROOT)-$(VERSION)
@@ -171,7 +172,7 @@ endif
 
 CFLAGS += -I$(PWD)/libsysfs
 
-all: $(ROOT) $(SENDER) $(DAEMON) $(INFO) $(TESTER)
+all: $(ROOT) $(SENDER) $(DAEMON) $(INFO) $(TESTER) $(WAIT)
 	@extras="$(EXTRAS)" ; for target in $$extras ; do \
 		echo $$target ; \
 		$(MAKE) prefix=$(prefix) \
@@ -287,10 +288,14 @@ $(RULER): $(LIBC) $(RULER).o $(OBJS) $(HEADERS)
 	$(LD) $(LDFLAGS) -o $@ $(CRT0) udevruler.o udev_lib.o udev_config.o udevdb.o $(SYSFS) $(TDB) $(LIB_OBJS) $(ARCH_LIB_OBJS) -lnewt
 	$(STRIPCMD) $@
 
+$(WAIT): $(WAIT).o $(OBJS) $(HEADERS) $(LIBC)
+	$(LD) $(LDFLAGS) -o $@ $(CRT0) $(WAIT).o $(SYSFS) $(LIB_OBJS) $(ARCH_LIB_OBJS)
+	$(STRIPCMD) $@
+
 clean:
 	-find . \( -not -type d \) -and \( -name '*~' -o -name '*.[oas]' \) -type f -print \
 	 | xargs rm -f 
-	-rm -f core $(ROOT) $(GEN_HEADERS) $(GEN_CONFIGS) $(GEN_MANPAGES) $(INFO) $(DAEMON) $(SENDER) $(TESTER) $(RULER)
+	-rm -f core $(ROOT) $(GEN_HEADERS) $(GEN_CONFIGS) $(GEN_MANPAGES) $(INFO) $(DAEMON) $(SENDER) $(TESTER) $(RULER) $(WAIT)
 	$(MAKE) -C klibc clean
 	@extras="$(EXTRAS)" ; for target in $$extras ; do \
 		echo $$target ; \
@@ -391,8 +396,10 @@ install: install-initscript install-config install-man install-dev.d all
 	$(INSTALL_PROGRAM) -D $(SENDER) $(DESTDIR)$(sbindir)/$(SENDER)
 	$(INSTALL_PROGRAM) -D $(INFO) $(DESTDIR)$(usrbindir)/$(INFO)
 	$(INSTALL_PROGRAM) -D $(TESTER) $(DESTDIR)$(usrbindir)/$(TESTER)
-	ln -sf $(sbindir)/udev $(DESTDIR)$(sbindir)/$(STARTER)
+	$(INSTALL_PROGRAM) -D $(WAIT) $(DESTDIR)$(sbindir)/$(WAIT)
+	- ln -f -s $(sbindir)/udev $(DESTDIR)$(sbindir)/$(STARTER)
 	- ln -f -s $(sbindir)/$(SENDER) $(DESTDIR)$(hotplugdir)/10-udev.hotplug
+	- ln -f -s $(sbindir)/$(WAIT) $(DESTDIR)$(hotplugdir)/00-wait_for_sysfs.hotplug
 ifndef DESTDIR
 	- killall udevd
 	- rm -f $(udevdir)/.udev.tdb
@@ -405,6 +412,7 @@ endif
 
 uninstall: uninstall-man uninstall-dev.d
 	- rm $(hotplugdir)/10-udev.hotplug
+	- rm $(hotplugdir)/00-wait_for_sysfs.hotplug
 	- rm $(configdir)/rules.d/50-udev.rules
 	- rm $(configdir)/permissions.d/50-udev.permissions
 	- rm $(configdir)/udev.conf
@@ -418,6 +426,7 @@ uninstall: uninstall-man uninstall-dev.d
 	- rm $(sbindir)/$(STARTER)
 	- rm $(usrbindir)/$(INFO)
 	- rm $(usrbindir)/$(TESTER)
+	- rm $(usrbindir)/$(WAIT)
 	- rmdir $(hotplugdir)
 	- rm $(udevdir)/.udev.tdb
 	- rmdir $(udevdir)