1
1
mirror of https://github.com/systemd/systemd-stable.git synced 2024-10-30 14:55:26 +03:00
systemd-stable/wait_for_sysfs.c
kay.sievers@vrfy.org a8b5267a62 [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.
2005-04-26 21:37:02 -07:00

335 lines
8.1 KiB
C

/*
* 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;
}