From a8b5267a629f21c30d4e94ec82be193009803ddd Mon Sep 17 00:00:00 2001 From: "kay.sievers@vrfy.org" Date: Tue, 5 Oct 2004 21:35:39 -0700 Subject: [PATCH] [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. --- Makefile | 15 ++- wait_for_sysfs.c | 334 +++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 346 insertions(+), 3 deletions(-) create mode 100644 wait_for_sysfs.c diff --git a/Makefile b/Makefile index bc2f8526..67a7d465 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) diff --git a/wait_for_sysfs.c b/wait_for_sysfs.c new file mode 100644 index 00000000..b9efcddf --- /dev/null +++ b/wait_for_sysfs.c @@ -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 + * + * 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 +#include +#include +#include +#include +#include +#include +#include + +#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; +} -- 2.39.5