Systemd/src/udev/udev-event.c

917 lines
36 KiB
C
Raw Normal View History

/*
* Copyright (C) 2003-2013 Kay Sievers <kay@vrfy.org>
*
2008-09-10 02:40:42 +02:00
* 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, either version 2 of the License, or
* (at your option) any later version.
*
2008-09-10 02:40:42 +02:00
* 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, see <http://www.gnu.org/licenses/>.
*/
#include <stdlib.h>
#include <stdio.h>
#include <stddef.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
#include <ctype.h>
#include <string.h>
#include <time.h>
#include <net/if.h>
#include <sys/ioctl.h>
2011-04-20 01:53:03 +02:00
#include <sys/prctl.h>
#include <sys/poll.h>
#include <sys/epoll.h>
#include <sys/wait.h>
#include <sys/socket.h>
2011-04-20 01:53:03 +02:00
#include <sys/signalfd.h>
#include <linux/sockios.h>
#include "udev.h"
2008-10-16 17:16:58 +02:00
struct udev_event *udev_event_new(struct udev_device *dev)
{
struct udev *udev = udev_device_get_udev(dev);
struct udev_event *event;
event = calloc(1, sizeof(struct udev_event));
if (event == NULL)
return NULL;
event->dev = dev;
event->udev = udev;
udev_list_init(udev, &event->run_list, false);
udev_list_init(udev, &event->seclabel_list, false);
event->fd_signal = -1;
2012-11-11 20:45:05 +01:00
event->birth_usec = now(CLOCK_MONOTONIC);
event->timeout_usec = 30 * 1000 * 1000;
return event;
2008-10-16 17:16:58 +02:00
}
void udev_event_unref(struct udev_event *event)
{
if (event == NULL)
return;
udev_list_cleanup(&event->run_list);
udev_list_cleanup(&event->seclabel_list);
free(event->program_result);
free(event->name);
free(event);
2008-10-16 17:16:58 +02:00
}
2009-05-20 17:57:52 +02:00
size_t udev_event_apply_format(struct udev_event *event, const char *src, char *dest, size_t size)
{
struct udev_device *dev = event->dev;
enum subst_type {
SUBST_UNKNOWN,
SUBST_DEVNODE,
SUBST_ATTR,
SUBST_ENV,
SUBST_KERNEL,
SUBST_KERNEL_NUMBER,
SUBST_DRIVER,
SUBST_DEVPATH,
SUBST_ID,
SUBST_MAJOR,
SUBST_MINOR,
SUBST_RESULT,
SUBST_PARENT,
SUBST_NAME,
SUBST_LINKS,
SUBST_ROOT,
SUBST_SYS,
};
static const struct subst_map {
const char *name;
const char fmt;
enum subst_type type;
} map[] = {
2012-11-20 18:07:14 +01:00
{ .name = "devnode", .fmt = 'N', .type = SUBST_DEVNODE },
{ .name = "tempnode", .fmt = 'N', .type = SUBST_DEVNODE },
{ .name = "attr", .fmt = 's', .type = SUBST_ATTR },
{ .name = "sysfs", .fmt = 's', .type = SUBST_ATTR },
{ .name = "env", .fmt = 'E', .type = SUBST_ENV },
{ .name = "kernel", .fmt = 'k', .type = SUBST_KERNEL },
{ .name = "number", .fmt = 'n', .type = SUBST_KERNEL_NUMBER },
{ .name = "driver", .fmt = 'd', .type = SUBST_DRIVER },
{ .name = "devpath", .fmt = 'p', .type = SUBST_DEVPATH },
{ .name = "id", .fmt = 'b', .type = SUBST_ID },
{ .name = "major", .fmt = 'M', .type = SUBST_MAJOR },
{ .name = "minor", .fmt = 'm', .type = SUBST_MINOR },
{ .name = "result", .fmt = 'c', .type = SUBST_RESULT },
{ .name = "parent", .fmt = 'P', .type = SUBST_PARENT },
{ .name = "name", .fmt = 'D', .type = SUBST_NAME },
{ .name = "links", .fmt = 'L', .type = SUBST_LINKS },
{ .name = "root", .fmt = 'r', .type = SUBST_ROOT },
{ .name = "sys", .fmt = 'S', .type = SUBST_SYS },
};
const char *from;
char *s;
size_t l;
from = src;
s = dest;
l = size;
for (;;) {
enum subst_type type = SUBST_UNKNOWN;
char attrbuf[UTIL_PATH_SIZE];
char *attr = NULL;
while (from[0] != '\0') {
if (from[0] == '$') {
/* substitute named variable */
unsigned int i;
if (from[1] == '$') {
from++;
goto copy;
}
for (i = 0; i < ELEMENTSOF(map); i++) {
2012-04-16 20:27:44 +02:00
if (startswith(&from[1], map[i].name)) {
type = map[i].type;
from += strlen(map[i].name)+1;
goto subst;
}
}
} else if (from[0] == '%') {
/* substitute format char */
unsigned int i;
if (from[1] == '%') {
from++;
goto copy;
}
for (i = 0; i < ELEMENTSOF(map); i++) {
if (from[1] == map[i].fmt) {
type = map[i].type;
from += 2;
goto subst;
}
}
}
2009-05-20 17:57:52 +02:00
copy:
/* copy char */
if (l == 0)
goto out;
s[0] = from[0];
from++;
s++;
l--;
}
goto out;
2009-05-20 17:57:52 +02:00
subst:
/* extract possible $format{attr} */
if (from[0] == '{') {
unsigned int i;
from++;
for (i = 0; from[i] != '}'; i++) {
if (from[i] == '\0') {
log_error("missing closing brace for format '%s'\n", src);
goto out;
}
}
if (i >= sizeof(attrbuf))
goto out;
memcpy(attrbuf, from, i);
attrbuf[i] = '\0';
from += i+1;
attr = attrbuf;
} else {
attr = NULL;
}
switch (type) {
case SUBST_DEVPATH:
l = strpcpy(&s, l, udev_device_get_devpath(dev));
break;
case SUBST_KERNEL:
l = strpcpy(&s, l, udev_device_get_sysname(dev));
break;
case SUBST_KERNEL_NUMBER:
if (udev_device_get_sysnum(dev) == NULL)
break;
l = strpcpy(&s, l, udev_device_get_sysnum(dev));
break;
case SUBST_ID:
if (event->dev_parent == NULL)
break;
l = strpcpy(&s, l, udev_device_get_sysname(event->dev_parent));
break;
case SUBST_DRIVER: {
const char *driver;
if (event->dev_parent == NULL)
break;
driver = udev_device_get_driver(event->dev_parent);
if (driver == NULL)
break;
l = strpcpy(&s, l, driver);
break;
}
case SUBST_MAJOR: {
char num[UTIL_PATH_SIZE];
sprintf(num, "%d", major(udev_device_get_devnum(dev)));
l = strpcpy(&s, l, num);
break;
}
case SUBST_MINOR: {
char num[UTIL_PATH_SIZE];
sprintf(num, "%d", minor(udev_device_get_devnum(dev)));
l = strpcpy(&s, l, num);
break;
}
case SUBST_RESULT: {
char *rest;
int i;
if (event->program_result == NULL)
break;
/* get part part of the result string */
i = 0;
if (attr != NULL)
i = strtoul(attr, &rest, 10);
if (i > 0) {
char result[UTIL_PATH_SIZE];
char tmp[UTIL_PATH_SIZE];
char *cpos;
strscpy(result, sizeof(result), event->program_result);
cpos = result;
while (--i) {
while (cpos[0] != '\0' && !isspace(cpos[0]))
cpos++;
while (isspace(cpos[0]))
cpos++;
}
if (i > 0) {
log_error("requested part of result string not found\n");
break;
}
strscpy(tmp, sizeof(tmp), cpos);
/* %{2+}c copies the whole string from the second part on */
if (rest[0] != '+') {
cpos = strchr(tmp, ' ');
if (cpos)
cpos[0] = '\0';
}
l = strpcpy(&s, l, tmp);
} else {
l = strpcpy(&s, l, event->program_result);
}
break;
}
case SUBST_ATTR: {
const char *value = NULL;
char vbuf[UTIL_NAME_SIZE];
size_t len;
int count;
if (attr == NULL) {
log_error("missing file parameter for attr\n");
break;
}
/* try to read the value specified by "[dmi/id]product_name" */
if (util_resolve_subsys_kernel(event->udev, attr, vbuf, sizeof(vbuf), 1) == 0)
value = vbuf;
/* try to read the attribute the device */
if (value == NULL)
value = udev_device_get_sysattr_value(event->dev, attr);
/* try to read the attribute of the parent device, other matches have selected */
if (value == NULL && event->dev_parent != NULL && event->dev_parent != event->dev)
value = udev_device_get_sysattr_value(event->dev_parent, attr);
if (value == NULL)
break;
/* strip trailing whitespace, and replace unwanted characters */
if (value != vbuf)
strscpy(vbuf, sizeof(vbuf), value);
len = strlen(vbuf);
while (len > 0 && isspace(vbuf[--len]))
vbuf[len] = '\0';
count = util_replace_chars(vbuf, UDEV_ALLOWED_CHARS_INPUT);
if (count > 0)
log_debug("%i character(s) replaced\n" , count);
l = strpcpy(&s, l, vbuf);
break;
}
case SUBST_PARENT: {
struct udev_device *dev_parent;
const char *devnode;
dev_parent = udev_device_get_parent(event->dev);
if (dev_parent == NULL)
break;
devnode = udev_device_get_devnode(dev_parent);
if (devnode != NULL)
l = strpcpy(&s, l, devnode + strlen("/dev/"));
break;
}
case SUBST_DEVNODE:
if (udev_device_get_devnode(dev) != NULL)
l = strpcpy(&s, l, udev_device_get_devnode(dev));
break;
case SUBST_NAME:
if (event->name != NULL)
l = strpcpy(&s, l, event->name);
else if (udev_device_get_devnode(dev) != NULL)
l = strpcpy(&s, l, udev_device_get_devnode(dev) + strlen("/dev/"));
else
l = strpcpy(&s, l, udev_device_get_sysname(dev));
break;
case SUBST_LINKS: {
struct udev_list_entry *list_entry;
list_entry = udev_device_get_devlinks_list_entry(dev);
if (list_entry == NULL)
break;
l = strpcpy(&s, l, udev_list_entry_get_name(list_entry) + strlen("/dev/"));
udev_list_entry_foreach(list_entry, udev_list_entry_get_next(list_entry))
l = strpcpyl(&s, l, " ", udev_list_entry_get_name(list_entry) + strlen("/dev/"), NULL);
break;
}
case SUBST_ROOT:
l = strpcpy(&s, l, "/dev");
break;
case SUBST_SYS:
l = strpcpy(&s, l, "/sys");
break;
case SUBST_ENV:
if (attr == NULL) {
break;
} else {
const char *value;
value = udev_device_get_property_value(event->dev, attr);
if (value == NULL)
break;
l = strpcpy(&s, l, value);
break;
}
default:
log_error("unknown substitution type=%i\n", type);
break;
}
}
2009-05-20 17:57:52 +02:00
out:
s[0] = '\0';
return l;
}
2011-04-20 01:53:03 +02:00
static int spawn_exec(struct udev_event *event,
const char *cmd, char *const argv[], char **envp, const sigset_t *sigmask,
int fd_stdout, int fd_stderr)
2011-04-20 01:53:03 +02:00
{
int err;
int fd;
/* discard child output or connect to pipe */
fd = open("/dev/null", O_RDWR);
if (fd >= 0) {
dup2(fd, STDIN_FILENO);
if (fd_stdout < 0)
dup2(fd, STDOUT_FILENO);
if (fd_stderr < 0)
dup2(fd, STDERR_FILENO);
close(fd);
} else {
log_error("open /dev/null failed: %m\n");
}
/* connect pipes to std{out,err} */
if (fd_stdout >= 0) {
dup2(fd_stdout, STDOUT_FILENO);
close(fd_stdout);
}
if (fd_stderr >= 0) {
dup2(fd_stderr, STDERR_FILENO);
close(fd_stderr);
}
/* terminate child in case parent goes away */
prctl(PR_SET_PDEATHSIG, SIGTERM);
/* restore original udev sigmask before exec */
if (sigmask)
sigprocmask(SIG_SETMASK, sigmask, NULL);
execve(argv[0], argv, envp);
/* exec failed */
err = -errno;
log_error("failed to execute '%s' '%s': %m\n", argv[0], cmd);
return err;
2011-04-20 01:53:03 +02:00
}
static void spawn_read(struct udev_event *event,
const char *cmd,
int fd_stdout, int fd_stderr,
char *result, size_t ressize)
2011-04-20 01:53:03 +02:00
{
size_t respos = 0;
int fd_ep = -1;
struct epoll_event ep_outpipe, ep_errpipe;
/* read from child if requested */
if (fd_stdout < 0 && fd_stderr < 0)
return;
fd_ep = epoll_create1(EPOLL_CLOEXEC);
if (fd_ep < 0) {
log_error("error creating epoll fd: %m\n");
goto out;
}
if (fd_stdout >= 0) {
memset(&ep_outpipe, 0, sizeof(struct epoll_event));
ep_outpipe.events = EPOLLIN;
ep_outpipe.data.ptr = &fd_stdout;
if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_stdout, &ep_outpipe) < 0) {
log_error("fail to add fd to epoll: %m\n");
goto out;
}
}
if (fd_stderr >= 0) {
memset(&ep_errpipe, 0, sizeof(struct epoll_event));
ep_errpipe.events = EPOLLIN;
ep_errpipe.data.ptr = &fd_stderr;
if (epoll_ctl(fd_ep, EPOLL_CTL_ADD, fd_stderr, &ep_errpipe) < 0) {
log_error("fail to add fd to epoll: %m\n");
goto out;
}
}
/* read child output */
while (fd_stdout >= 0 || fd_stderr >= 0) {
int timeout;
int fdcount;
struct epoll_event ev[4];
int i;
if (event->timeout_usec > 0) {
2012-11-11 20:45:05 +01:00
usec_t age_usec;
2012-11-11 20:45:05 +01:00
age_usec = now(CLOCK_MONOTONIC) - event->birth_usec;
if (age_usec >= event->timeout_usec) {
log_error("timeout '%s'\n", cmd);
goto out;
}
timeout = ((event->timeout_usec - age_usec) / 1000) + 1000;
} else {
timeout = -1;
}
fdcount = epoll_wait(fd_ep, ev, ELEMENTSOF(ev), timeout);
if (fdcount < 0) {
if (errno == EINTR)
continue;
log_error("failed to poll: %m\n");
goto out;
}
if (fdcount == 0) {
log_error("timeout '%s'\n", cmd);
goto out;
}
for (i = 0; i < fdcount; i++) {
int *fd = (int *)ev[i].data.ptr;
if (ev[i].events & EPOLLIN) {
ssize_t count;
char buf[4096];
count = read(*fd, buf, sizeof(buf)-1);
if (count <= 0)
continue;
buf[count] = '\0';
/* store stdout result */
if (result != NULL && *fd == fd_stdout) {
if (respos + count < ressize) {
memcpy(&result[respos], buf, count);
respos += count;
} else {
log_error("'%s' ressize %zd too short\n", cmd, ressize);
}
}
/* log debug output only if we watch stderr */
if (fd_stderr >= 0) {
char *pos;
char *line;
pos = buf;
while ((line = strsep(&pos, "\n"))) {
if (pos != NULL || line[0] != '\0')
log_debug("'%s'(%s) '%s'\n", cmd, *fd == fd_stdout ? "out" : "err" , line);
}
}
} else if (ev[i].events & EPOLLHUP) {
if (epoll_ctl(fd_ep, EPOLL_CTL_DEL, *fd, NULL) < 0) {
log_error("failed to remove fd from epoll: %m\n");
goto out;
}
*fd = -1;
}
}
}
/* return the child's stdout string */
if (result != NULL)
result[respos] = '\0';
2011-04-20 01:53:03 +02:00
out:
if (fd_ep >= 0)
close(fd_ep);
2011-04-20 01:53:03 +02:00
}
static int spawn_wait(struct udev_event *event, const char *cmd, pid_t pid)
{
struct pollfd pfd[1];
int err = 0;
pfd[0].events = POLLIN;
pfd[0].fd = event->fd_signal;
while (pid > 0) {
int timeout;
int fdcount;
if (event->timeout_usec > 0) {
2012-11-11 20:45:05 +01:00
usec_t age_usec;
2012-11-11 20:45:05 +01:00
age_usec = now(CLOCK_MONOTONIC) - event->birth_usec;
if (age_usec >= event->timeout_usec)
timeout = 1000;
else
timeout = ((event->timeout_usec - age_usec) / 1000) + 1000;
} else {
timeout = -1;
}
fdcount = poll(pfd, 1, timeout);
if (fdcount < 0) {
if (errno == EINTR)
continue;
err = -errno;
log_error("failed to poll: %m\n");
goto out;
}
if (fdcount == 0) {
log_error("timeout: killing '%s' [%u]\n", cmd, pid);
kill(pid, SIGKILL);
}
if (pfd[0].revents & POLLIN) {
struct signalfd_siginfo fdsi;
int status;
ssize_t size;
size = read(event->fd_signal, &fdsi, sizeof(struct signalfd_siginfo));
if (size != sizeof(struct signalfd_siginfo))
continue;
switch (fdsi.ssi_signo) {
case SIGTERM:
event->sigterm = true;
break;
case SIGCHLD:
if (waitpid(pid, &status, WNOHANG) < 0)
break;
if (WIFEXITED(status)) {
log_debug("'%s' [%u] exit with return code %i\n", cmd, pid, WEXITSTATUS(status));
if (WEXITSTATUS(status) != 0)
err = -1;
} else if (WIFSIGNALED(status)) {
log_error("'%s' [%u] terminated by signal %i (%s)\n", cmd, pid, WTERMSIG(status), strsignal(WTERMSIG(status)));
err = -1;
} else if (WIFSTOPPED(status)) {
log_error("'%s' [%u] stopped\n", cmd, pid);
err = -1;
} else if (WIFCONTINUED(status)) {
log_error("'%s' [%u] continued\n", cmd, pid);
err = -1;
} else {
log_error("'%s' [%u] exit with status 0x%04x\n", cmd, pid, status);
err = -1;
}
pid = 0;
break;
}
}
}
2011-04-20 01:53:03 +02:00
out:
return err;
2011-04-20 01:53:03 +02:00
}
2011-12-23 02:02:44 +01:00
int udev_build_argv(struct udev *udev, char *cmd, int *argc, char *argv[])
{
int i = 0;
char *pos;
if (strchr(cmd, ' ') == NULL) {
argv[i++] = cmd;
goto out;
}
pos = cmd;
while (pos != NULL && pos[0] != '\0') {
if (pos[0] == '\'') {
/* do not separate quotes */
pos++;
argv[i] = strsep(&pos, "\'");
if (pos != NULL)
while (pos[0] == ' ')
pos++;
} else {
argv[i] = strsep(&pos, " ");
if (pos != NULL)
while (pos[0] == ' ')
pos++;
}
i++;
}
2011-12-23 02:02:44 +01:00
out:
argv[i] = NULL;
if (argc)
*argc = i;
return 0;
2011-12-23 02:02:44 +01:00
}
2011-04-20 01:53:03 +02:00
int udev_event_spawn(struct udev_event *event,
const char *cmd, char **envp, const sigset_t *sigmask,
char *result, size_t ressize)
2011-04-20 01:53:03 +02:00
{
struct udev *udev = event->udev;
int outpipe[2] = {-1, -1};
int errpipe[2] = {-1, -1};
pid_t pid;
char arg[UTIL_PATH_SIZE];
char *argv[128];
char program[UTIL_PATH_SIZE];
int err = 0;
strscpy(arg, sizeof(arg), cmd);
udev_build_argv(event->udev, arg, NULL, argv);
/* pipes from child to parent */
if (result != NULL || udev_get_log_priority(udev) >= LOG_INFO) {
if (pipe2(outpipe, O_NONBLOCK) != 0) {
err = -errno;
log_error("pipe failed: %m\n");
goto out;
}
}
if (udev_get_log_priority(udev) >= LOG_INFO) {
if (pipe2(errpipe, O_NONBLOCK) != 0) {
err = -errno;
log_error("pipe failed: %m\n");
goto out;
}
}
/* allow programs in /usr/lib/udev/ to be called without the path */
if (argv[0][0] != '/') {
strscpyl(program, sizeof(program), UDEVLIBEXECDIR "/", argv[0], NULL);
argv[0] = program;
}
pid = fork();
switch(pid) {
case 0:
/* child closes parent's ends of pipes */
if (outpipe[READ_END] >= 0) {
close(outpipe[READ_END]);
outpipe[READ_END] = -1;
}
if (errpipe[READ_END] >= 0) {
close(errpipe[READ_END]);
errpipe[READ_END] = -1;
}
log_debug("starting '%s'\n", cmd);
spawn_exec(event, cmd, argv, envp, sigmask,
outpipe[WRITE_END], errpipe[WRITE_END]);
_exit(2 );
case -1:
log_error("fork of '%s' failed: %m\n", cmd);
err = -1;
goto out;
default:
/* parent closed child's ends of pipes */
if (outpipe[WRITE_END] >= 0) {
close(outpipe[WRITE_END]);
outpipe[WRITE_END] = -1;
}
if (errpipe[WRITE_END] >= 0) {
close(errpipe[WRITE_END]);
errpipe[WRITE_END] = -1;
}
spawn_read(event, cmd,
outpipe[READ_END], errpipe[READ_END],
result, ressize);
err = spawn_wait(event, cmd, pid);
}
2011-04-20 01:53:03 +02:00
out:
if (outpipe[READ_END] >= 0)
close(outpipe[READ_END]);
if (outpipe[WRITE_END] >= 0)
close(outpipe[WRITE_END]);
if (errpipe[READ_END] >= 0)
close(errpipe[READ_END]);
if (errpipe[WRITE_END] >= 0)
close(errpipe[WRITE_END]);
return err;
2011-04-20 01:53:03 +02:00
}
2008-10-16 17:16:58 +02:00
static int rename_netif(struct udev_event *event)
{
struct udev_device *dev = event->dev;
int sk;
struct ifreq ifr;
int err;
log_debug("changing net interface name from '%s' to '%s'\n",
udev_device_get_sysname(dev), event->name);
sk = socket(PF_INET, SOCK_DGRAM, 0);
if (sk < 0) {
err = -errno;
log_error("error opening socket: %m\n");
return err;
}
memset(&ifr, 0x00, sizeof(struct ifreq));
strscpy(ifr.ifr_name, IFNAMSIZ, udev_device_get_sysname(dev));
strscpy(ifr.ifr_newname, IFNAMSIZ, event->name);
err = ioctl(sk, SIOCSIFNAME, &ifr);
if (err >= 0) {
print_kmsg("renamed network interface %s to %s\n", ifr.ifr_name, ifr.ifr_newname);
} else {
err = -errno;
log_error("error changing net interface name %s to %s: %m\n", ifr.ifr_name, ifr.ifr_newname);
}
close(sk);
return err;
}
2011-04-20 01:53:03 +02:00
int udev_event_execute_rules(struct udev_event *event, struct udev_rules *rules, const sigset_t *sigmask)
{
struct udev_device *dev = event->dev;
int err = 0;
if (udev_device_get_subsystem(dev) == NULL)
return -1;
2013-02-13 18:13:22 +01:00
if (streq(udev_device_get_action(dev), "remove")) {
udev_device_read_db(dev, NULL);
udev_device_delete_db(dev);
udev_device_tag_index(dev, NULL, false);
if (major(udev_device_get_devnum(dev)) != 0)
udev_watch_end(event->udev, dev);
udev_rules_apply_to_event(rules, event, sigmask);
if (major(udev_device_get_devnum(dev)) != 0)
udev_node_remove(dev);
} else {
udev: properly handle symlink removal by 'change' event If a 'change' event is supposed to remove created symlinks, we create a new device structure from the sysfs device and fill it with the list of links, to compute the delta of the old and new list of links to apply. If the device is already 'remove'd by the kernel though, udev fails to create the device structure, so the links are not removed properly. > From: Neil Brown <nfbrown@suse.com> > Date: Thu, 8 Nov 2012 10:39:06 +0100 > Subject: [PATCH] If a 'change' event does not get handled by udev until > after the device has subsequently disappeared, udev mis-handles > it. This can happen with 'md' devices which emit a change > event and then a remove event when they are stopped. It is > normally only noticed if udev is very busy (lots of arrays > being stopped at once) or the machine is otherwise loaded > and reponding slowly. > > There are two problems. > > 1/ udev_device_new_from_syspath() will refuse to create the device > structure if the device does not exist in /sys, and particularly if > the uevent file does not exist. > If a 'db' file does exist, that is sufficient evidence that the device > is genuine and should be created. Equally if we have just received an > event from the kernel about the device, it must be real. > > This patch just disabled the test for the 'uevent' file, it doesn't > try imposing any other tests - it isn't clear that they are really > needed. > > 2/ udev_event_execute_rules() calls udev_device_read_db() on a 'device' > structure that is largely uninitialised and in particular does not > have the 'subsystem' set. udev_device_read_db() needs the subsystem > so it tries to read the 'subsystem' symlink out of sysfs. If the > device is already deleted, this naturally fails. > udev_event_execute_rules() knows the subsystem (as it was in the > event message) so this patch simply sets the subsystem for the device > structure to be loaded to match the subsystem of the device structure > that is handling the event. > > With these two changes, deleted handling of change events will still > correctly remove any symlinks that are not needed any more. Use udev_device_new() instead of allowing udev_device_new_from_syspath() to proceed without a sysfs device.
2012-11-13 02:05:06 +01:00
event->dev_db = udev_device_new(event->udev);
if (event->dev_db != NULL) {
udev: properly handle symlink removal by 'change' event If a 'change' event is supposed to remove created symlinks, we create a new device structure from the sysfs device and fill it with the list of links, to compute the delta of the old and new list of links to apply. If the device is already 'remove'd by the kernel though, udev fails to create the device structure, so the links are not removed properly. > From: Neil Brown <nfbrown@suse.com> > Date: Thu, 8 Nov 2012 10:39:06 +0100 > Subject: [PATCH] If a 'change' event does not get handled by udev until > after the device has subsequently disappeared, udev mis-handles > it. This can happen with 'md' devices which emit a change > event and then a remove event when they are stopped. It is > normally only noticed if udev is very busy (lots of arrays > being stopped at once) or the machine is otherwise loaded > and reponding slowly. > > There are two problems. > > 1/ udev_device_new_from_syspath() will refuse to create the device > structure if the device does not exist in /sys, and particularly if > the uevent file does not exist. > If a 'db' file does exist, that is sufficient evidence that the device > is genuine and should be created. Equally if we have just received an > event from the kernel about the device, it must be real. > > This patch just disabled the test for the 'uevent' file, it doesn't > try imposing any other tests - it isn't clear that they are really > needed. > > 2/ udev_event_execute_rules() calls udev_device_read_db() on a 'device' > structure that is largely uninitialised and in particular does not > have the 'subsystem' set. udev_device_read_db() needs the subsystem > so it tries to read the 'subsystem' symlink out of sysfs. If the > device is already deleted, this naturally fails. > udev_event_execute_rules() knows the subsystem (as it was in the > event message) so this patch simply sets the subsystem for the device > structure to be loaded to match the subsystem of the device structure > that is handling the event. > > With these two changes, deleted handling of change events will still > correctly remove any symlinks that are not needed any more. Use udev_device_new() instead of allowing udev_device_new_from_syspath() to proceed without a sysfs device.
2012-11-13 02:05:06 +01:00
udev_device_set_syspath(event->dev_db, udev_device_get_syspath(dev));
udev_device_set_subsystem(event->dev_db, udev_device_get_subsystem(dev));
udev_device_read_db(event->dev_db, NULL);
udev_device_set_info_loaded(event->dev_db);
/* disable watch during event processing */
if (major(udev_device_get_devnum(dev)) != 0)
udev_watch_end(event->udev, event->dev_db);
}
udev_rules_apply_to_event(rules, event, sigmask);
/* rename a new network interface, if needed */
2013-02-13 18:13:22 +01:00
if (udev_device_get_ifindex(dev) > 0 && streq(udev_device_get_action(dev), "add") &&
event->name != NULL && !streq(event->name, udev_device_get_sysname(dev))) {
char syspath[UTIL_PATH_SIZE];
char *pos;
err = rename_netif(event);
if (err == 0) {
log_debug("renamed netif to '%s'\n", event->name);
/* remember old name */
udev_device_add_property(dev, "INTERFACE_OLD", udev_device_get_sysname(dev));
/* now change the devpath, because the kernel device name has changed */
strscpy(syspath, sizeof(syspath), udev_device_get_syspath(dev));
pos = strrchr(syspath, '/');
if (pos != NULL) {
pos++;
strscpy(pos, sizeof(syspath) - (pos - syspath), event->name);
udev_device_set_syspath(event->dev, syspath);
udev_device_add_property(dev, "INTERFACE", udev_device_get_sysname(dev));
log_debug("changed devpath to '%s'\n", udev_device_get_devpath(dev));
}
}
}
if (major(udev_device_get_devnum(dev)) > 0) {
bool apply;
/* remove/update possible left-over symlinks from old database entry */
if (event->dev_db != NULL)
udev_node_update_old_links(dev, event->dev_db);
if (!event->owner_set)
event->uid = udev_device_get_devnode_uid(dev);
if (!event->group_set)
event->gid = udev_device_get_devnode_gid(dev);
if (!event->mode_set) {
if (udev_device_get_devnode_mode(dev) > 0) {
/* kernel supplied value */
event->mode = udev_device_get_devnode_mode(dev);
} else if (event->gid > 0) {
/* default 0660 if a group is assigned */
event->mode = 0660;
} else {
/* default 0600 */
event->mode = 0600;
}
}
apply = streq(udev_device_get_action(dev), "add") || event->owner_set || event->group_set || event->mode_set;
udev_node_add(dev, apply, event->mode, event->uid, event->gid, &event->seclabel_list);
}
/* preserve old, or get new initialization timestamp */
if (event->dev_db != NULL && udev_device_get_usec_initialized(event->dev_db) > 0)
udev_device_set_usec_initialized(event->dev, udev_device_get_usec_initialized(event->dev_db));
else if (udev_device_get_usec_initialized(event->dev) == 0)
2012-11-11 20:45:05 +01:00
udev_device_set_usec_initialized(event->dev, now(CLOCK_MONOTONIC));
/* (re)write database file */
udev_device_update_db(dev);
udev_device_tag_index(dev, event->dev_db, true);
udev_device_set_is_initialized(dev);
udev_device_unref(event->dev_db);
event->dev_db = NULL;
}
return err;
}
2012-04-09 16:37:54 +02:00
void udev_event_execute_run(struct udev_event *event, const sigset_t *sigmask)
{
struct udev_list_entry *list_entry;
udev_list_entry_foreach(list_entry, udev_list_get_entry(&event->run_list)) {
const char *cmd = udev_list_entry_get_name(list_entry);
2012-04-09 16:37:54 +02:00
enum udev_builtin_cmd builtin_cmd = udev_list_entry_get_num(list_entry);
if (builtin_cmd < UDEV_BUILTIN_MAX) {
char command[UTIL_PATH_SIZE];
2012-04-09 16:37:54 +02:00
udev_event_apply_format(event, cmd, command, sizeof(command));
udev_builtin_run(event->dev, builtin_cmd, command, false);
} else {
char program[UTIL_PATH_SIZE];
char **envp;
if (event->exec_delay > 0) {
log_debug("delay execution of '%s'\n", program);
sleep(event->exec_delay);
}
udev_event_apply_format(event, cmd, program, sizeof(program));
envp = udev_device_get_properties_envp(event->dev);
2012-04-09 16:37:54 +02:00
udev_event_spawn(event, program, envp, sigmask, NULL, 0);
}
}
}