chiark / gitweb /
[PATCH] finally solve the bad sysfs-timing for all of us
authorkay.sievers@vrfy.org <kay.sievers@vrfy.org>
Wed, 6 Oct 2004 04:35:39 +0000 (21:35 -0700)
committerGreg KH <gregkh@suse.de>
Wed, 27 Apr 2005 04:37:02 +0000 (21:37 -0700)
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.

Makefile
wait_for_sysfs.c [new file with mode: 0644]

index bc2f852..67a7d46 100644 (file)
--- 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)
diff --git a/wait_for_sysfs.c b/wait_for_sysfs.c
new file mode 100644 (file)
index 0000000..b9efcdd
--- /dev/null
@@ -0,0 +1,334 @@
+/*
+ * wait_for_sysfs.c  - small program to delay the execution
+ *                    of /etc/hotplug.d/ programs, until sysfs
+ *                    is populated by the kernel. Depending on
+ *                    the type of device, we wait for all expected
+ *                    directories and then just exit.
+ *
+ * Copyright (C) 2004 Kay Sievers <kay.sievers@vrfy.org>
+ *
+ *     This program is free software; you can redistribute it and/or modify it
+ *     under the terms of the GNU General Public License as published by the
+ *     Free Software Foundation version 2 of the License.
+ * 
+ *     This program is distributed in the hope that it will be useful, but
+ *     WITHOUT ANY WARRANTY; without even the implied warranty of
+ *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *     General Public License for more details.
+ * 
+ *     You should have received a copy of the GNU General Public License along
+ *     with this program; if not, write to the Free Software Foundation, Inc.,
+ *     675 Mass Ave, Cambridge, MA 02139, USA.
+ *
+ */
+
+#include <stdio.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <string.h>
+#include <ctype.h>
+#include <errno.h>
+#include <sys/stat.h>
+
+#include "logging.h"
+#include "libsysfs/sysfs/libsysfs.h"
+
+#ifdef LOG
+unsigned char logname[LOGNAME_SIZE];
+void log_message(int level, const char *format, ...)
+{
+       va_list args;
+
+       va_start(args, format);
+       vsyslog(level, format, args);
+       va_end(args);
+}
+#endif
+
+#define WAIT_MAX_SECONDS               5
+#define WAIT_LOOP_PER_SECOND           20
+
+static int wait_for_class_device_attributes(struct sysfs_class_device *class_dev)
+{
+       static struct class_file {
+               char *subsystem;
+               char *file;
+       } class_files[] = {
+               { .subsystem = "net",           .file = "ifindex" },
+               { .subsystem = "usb_host",      .file = NULL },
+               { .subsystem = "pcmcia_socket", .file = NULL },
+               { NULL, NULL }
+       };
+       struct class_file *classfile;
+       const char *file = "dev";
+       int loop;
+
+       /* look if we want to look for another file instead of "dev" */
+       for (classfile = class_files; classfile->subsystem != NULL; classfile++) {
+               if (strcmp(class_dev->classname, classfile->subsystem) == 0) {
+                       if (classfile->file == NULL) {
+                               dbg("class '%s' has no file to wait for", class_dev->classname);
+                               return 0;
+                       }
+                       file = classfile->file;
+                       break;
+               }
+       }
+       dbg("looking at class '%s' for specific file '%s'", class_dev->classname, file);
+
+       loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+       while (--loop) {
+               if (sysfs_get_classdev_attr(class_dev, file) != NULL) {
+                       dbg("class '%s' specific file '%s' found", class_dev->classname, file);
+                       return 0;
+               }
+       }
+
+       dbg("error: getting bus '%s' specific file '%s'", class_dev->classname, file);
+       return -1;
+}
+
+static int class_device_expect_no_device_link(struct sysfs_class_device *class_dev)
+{
+       char **device;
+
+       static char *devices_without_link[] = {
+               "nb",
+               "ram",
+               "loop",
+               "fd",
+               "md",
+               "dos_cd",
+               "double",
+               "flash",
+               "msd",
+               "rflash",
+               "rom",
+               "rrom",
+               "sbpcd",
+               "pcd",
+               "pf",
+               "scd",
+               "sit",
+               "lp",
+               "ubd",
+               "vcs",
+               "vcsa",
+               "console",
+               "tty",
+               "ttyS",
+               NULL
+       };
+
+       for (device = devices_without_link; *device != NULL; device++) {
+               int len = strlen(*device);
+
+               /* look if name matches */
+               if (strncmp(class_dev->name, *device, len) != 0)
+                       continue;
+
+               /* exact match */
+               if (strlen(class_dev->name) == len)
+                       return 1;
+
+               /* instance numbers are matching too */
+               if (isdigit(class_dev->name[len]))
+                       return 1;
+       }
+
+       return 0;
+}
+
+static int wait_for_bus_device(struct sysfs_device *device_dev)
+{
+       static struct bus_file {
+               char *bus;
+               char *file;
+       } bus_files[] = {
+               { .bus = "scsi",        .file = "vendor" },
+               { .bus = "usb",         .file = "idVendor" },
+               { .bus = "usb",         .file = "iInterface" },
+               { .bus = "usb-serial",  .file = "detach_state" },
+               { .bus = "ide",         .file = "detach_state" },
+               { .bus = "pci",         .file = "vendor" },
+               { NULL }
+       };
+       struct bus_file *busfile;
+       int loop;
+
+       /* wait for the /bus-device link to the /device-device */
+       loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+       while (--loop) {
+               if (sysfs_get_device_bus(device_dev) == 0)
+                       break;
+
+               usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
+       }
+       if (loop == 0) {
+               dbg("error: getting /bus-device link");
+               return -1;
+       }
+       dbg("/bus-device link found for bus '%s'", device_dev->bus);
+
+       /* wait for a bus specific file to show up */
+       loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+       while (--loop) {
+               for (busfile = bus_files; busfile->bus != NULL; busfile++) {
+                       if (strcmp(device_dev->bus, busfile->bus) == 0) {
+                               dbg("looking at bus '%s' for specific file '%s'", device_dev->bus, busfile->file);
+                               if (sysfs_get_device_attr(device_dev, busfile->file) != NULL) {
+                                       dbg("bus '%s' specific file '%s' found", device_dev->bus, busfile->file);
+                                       return 0;
+                               }
+                               if (busfile->bus == NULL) {
+                                       info("error: unknown bus, update the build-in list '%s'", device_dev->bus);
+                                       return -1;
+                               }
+                       }
+               }
+       }
+
+       dbg("error: getting bus '%s' specific file '%s'", device_dev->bus, busfile->file);
+       return -1;
+}
+
+int main(int argc, char *argv[], char *envp[])
+{
+       const char *devpath = "";
+       const char *action;
+       const char *subsystem;
+       char sysfs_path[SYSFS_PATH_MAX];
+       char filename[SYSFS_PATH_MAX];
+       struct sysfs_class_device *class_dev;
+       struct sysfs_class_device *class_dev_parent;
+       struct sysfs_device *device_dev = NULL;
+       int loop;
+       int rc = 0;
+
+       if (argc != 2) {
+               dbg("error: subsystem");
+               return 1;
+       }
+       subsystem = argv[1];
+
+       devpath = getenv ("DEVPATH");
+       if (!devpath) {
+               dbg("error: no DEVPATH");
+               return 1;
+       }
+
+       action = getenv ("ACTION");
+       if (!action) {
+               dbg("error: no ACTION");
+               return 1;
+       }
+
+       if (strcmp(action, "add") != 0)
+               return 0;
+
+       if (sysfs_get_mnt_path(sysfs_path, SYSFS_PATH_MAX) != 0) {
+               dbg("error: no sysfs path");
+               return 2;
+       }
+
+       if ((strncmp(devpath, "/block/", 7) == 0) || (strncmp(devpath, "/class/", 7) == 0)) {
+               /* open the class device we are called for */
+               snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
+               filename[SYSFS_PATH_MAX-1] = '\0';
+
+               loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+               while (--loop) {
+                       class_dev = sysfs_open_class_device_path(filename);
+                       if (class_dev)
+                               break;
+               }
+               if (class_dev == NULL) {
+                       dbg("error: getting class_device");
+                       rc = 4;
+                       goto exit;
+               }
+               dbg("class_device opened '%s'", filename);
+
+               wait_for_class_device_attributes(class_dev);
+
+               if (class_device_expect_no_device_link(class_dev)) {
+                       dbg("no device symlink expected");
+                       sysfs_close_class_device(class_dev);
+                       goto exit;
+               }
+
+               /* the symlink may be on the parent device */
+               class_dev_parent = sysfs_get_classdev_parent(class_dev);
+               if (class_dev_parent)
+                       dbg("looking at parent device for device link '%s'", class_dev_parent->path);
+
+               /* wait for the symlink to the /device-device */
+               dbg("waiting for symlink to /device-device");
+               loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+               while (--loop) {
+                       if (class_dev_parent)
+                               device_dev = sysfs_get_classdev_device(class_dev_parent);
+                       else
+                               device_dev = sysfs_get_classdev_device(class_dev);
+
+                       if (device_dev)
+                               break;
+
+                       usleep(1000 * 1000 / WAIT_LOOP_PER_SECOND);
+               }
+               if (device_dev == NULL) {
+                       dbg("error: getting /device-device");
+                       sysfs_close_class_device(class_dev);
+                       rc = 5;
+                       goto exit;
+               }
+               dbg("device symlink found pointing to '%s'", device_dev->path);
+
+               /* wait for the bus value */
+               if (wait_for_bus_device(device_dev) != 0)
+                       rc = 6;
+               sysfs_close_class_device(class_dev);
+
+               /* finished */
+               goto exit;
+
+       } else if ((strncmp(devpath, "/devices/", 9) == 0)) {
+               /* open the path we are called for */
+               snprintf(filename, SYSFS_PATH_MAX-1, "%s%s", sysfs_path, devpath);
+               filename[SYSFS_PATH_MAX-1] = '\0';
+
+               loop = WAIT_MAX_SECONDS * WAIT_LOOP_PER_SECOND;
+               while (--loop) {
+                       device_dev = sysfs_open_device_path(filename);
+                       if (device_dev)
+                               break;
+               }
+               if (device_dev == NULL) {
+                       dbg("error: getting /device-device");
+                       rc = 4;
+                       goto exit;
+               }
+               dbg("device_device opened '%s'", filename);
+
+               /* wait for the bus value */
+               if (wait_for_bus_device(device_dev) != 0)
+                       rc = 9;
+
+               sysfs_close_device(device_dev);
+
+               /* finished */
+               goto exit;
+
+       } else {
+               dbg("unhandled sysfs path, no need to wait");
+       }
+
+exit:
+       if (rc == 0)
+               info("result: waiting for sysfs successful '%s'", devpath);
+       else
+               info("result: waiting for sysfs failed '%s'", devpath);
+
+       return rc;
+}