#include <time.h>
#include <getopt.h>
#include <dirent.h>
+#include <sys/file.h>
#include <sys/time.h>
#include <sys/prctl.h>
#include <sys/socket.h>
#include <sys/utsname.h>
#include "udev.h"
+#include "udev-util.h"
#include "sd-daemon.h"
#include "cgroup-util.h"
#include "dev-setup.h"
for (;;) {
struct udev_event *udev_event;
struct worker_message msg;
- int err;
+ int fd_lock = -1;
+ int err = 0;
log_debug("seq %llu running", udev_device_get_seqnum(dev));
udev_event = udev_event_new(dev);
if (exec_delay > 0)
udev_event->exec_delay = exec_delay;
+ /*
+ * Take a "read lock" on the device node; this establishes
+ * a concept of device "ownership" to serialize device
+ * access. External processes holding a "write lock" will
+ * cause udev to skip the event handling; in the case udev
+ * acquired the lock, the external process will block until
+ * udev has finished its event handling.
+ */
+
+ /*
+ * <kabi_> since we make check - device seems unused - we try
+ * ioctl to deactivate - and device is found to be opened
+ * <kay> sure, you try to take a write lock
+ * <kay> if you get it udev is out
+ * <kay> if you can't get it, udev is busy
+ * <kabi_> we cannot deactivate openned device (as it is in-use)
+ * <kay> maybe we should just exclude dm from that thing entirely
+ * <kabi_> IMHO this sounds like a good plan for this moment
+ */
+ if (streq_ptr("block", udev_device_get_subsystem(dev)) &&
+ !startswith("dm-", udev_device_get_sysname(dev))) {
+ struct udev_device *d = dev;
+
+ if (streq_ptr("partition", udev_device_get_devtype(d)))
+ d = udev_device_get_parent(d);
+
+ if (d) {
+ fd_lock = open(udev_device_get_devnode(d), O_RDONLY|O_CLOEXEC|O_NOFOLLOW|O_NONBLOCK);
+ if (fd_lock >= 0 && flock(fd_lock, LOCK_SH|LOCK_NB) < 0) {
+ log_debug("Unable to flock(%s), skipping event handling: %m", udev_device_get_devnode(d));
+ err = -EWOULDBLOCK;
+ fd_lock = safe_close(fd_lock);
+ goto skip;
+ }
+ }
+ }
+
/* apply rules, create node, symlinks */
- err = udev_event_execute_rules(udev_event, rules, &sigmask_orig);
+ udev_event_execute_rules(udev_event, rules, &sigmask_orig);
- if (err == 0)
- udev_event_execute_run(udev_event, &sigmask_orig);
+ udev_event_execute_run(udev_event, &sigmask_orig);
/* apply/restore inotify watch */
- if (err == 0 && udev_event->inotify_watch) {
+ if (udev_event->inotify_watch) {
udev_watch_begin(udev, dev);
udev_device_update_db(dev);
}
+ safe_close(fd_lock);
+
/* send processed event back to libudev listeners */
udev_monitor_send_device(worker_monitor, NULL, dev);
+skip:
/* send udevd the result of the event execution */
memzero(&msg, sizeof(struct worker_message));
- if (err != 0)
- msg.exitcode = err;
+ msg.exitcode = err;
msg.pid = getpid();
send(worker_watch[WRITE_END], &msg, sizeof(struct worker_message), 0);
}
out:
udev_device_unref(dev);
- if (fd_signal >= 0)
- close(fd_signal);
- if (fd_ep >= 0)
- close(fd_ep);
+ safe_close(fd_signal);
+ safe_close(fd_ep);
close(fd_inotify);
close(worker_watch[WRITE_END]);
udev_rules_unref(rules);
return udev_ctrl_connection_unref(ctrl_conn);
}
-/* read inotify messages */
+static int synthesize_change(struct udev_device *dev) {
+ char filename[UTIL_PATH_SIZE];
+ int r;
+
+ log_debug("device %s closed, synthesising 'change'", udev_device_get_devnode(dev));
+ strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
+ write_string_file(filename, "change");
+
+ /* for disks devices, re-trigger all partitions too */
+ if (streq_ptr("block", udev_device_get_subsystem(dev)) &&
+ streq_ptr("disk", udev_device_get_devtype(dev))) {
+ struct udev *udev = udev_device_get_udev(dev);
+ _cleanup_udev_enumerate_unref_ struct udev_enumerate *e = NULL;
+ struct udev_list_entry *item;
+
+ e = udev_enumerate_new(udev);
+ if (!e)
+ return -ENOMEM;
+
+ r = udev_enumerate_add_match_parent(e, dev);
+ if (r < 0)
+ return r;
+
+ r = udev_enumerate_add_match_subsystem(e, "block");
+ if (r < 0)
+ return r;
+
+ r = udev_enumerate_scan_devices(e);
+ udev_list_entry_foreach(item, udev_enumerate_get_list_entry(e)) {
+ _cleanup_udev_device_unref_ struct udev_device *d = NULL;
+
+ d = udev_device_new_from_syspath(udev, udev_list_entry_get_name(item));
+ if (!d)
+ continue;
+
+ if (!streq_ptr("partition", udev_device_get_devtype(d)))
+ continue;
+
+ log_debug("device %s closed, synthesising partition '%s' 'change'",
+ udev_device_get_devnode(dev), udev_device_get_devnode(d));
+ strscpyl(filename, sizeof(filename), udev_device_get_syspath(d), "/uevent", NULL);
+ write_string_file(filename, "change");
+ }
+ }
+
+ return 0;
+}
+
static int handle_inotify(struct udev *udev)
{
int nbytes, pos;
char *buf;
struct inotify_event *ev;
+ int r;
- if ((ioctl(fd_inotify, FIONREAD, &nbytes) < 0) || (nbytes <= 0))
- return 0;
+ r = ioctl(fd_inotify, FIONREAD, &nbytes);
+ if (r < 0 || nbytes <= 0)
+ return -errno;
buf = malloc(nbytes);
- if (buf == NULL) {
+ if (!buf) {
log_error("error getting buffer for inotify");
- return -1;
+ return -ENOMEM;
}
nbytes = read(fd_inotify, buf, nbytes);
ev = (struct inotify_event *)(buf + pos);
dev = udev_watch_lookup(udev, ev->wd);
- if (dev != NULL) {
- log_debug("inotify event: %x for %s", ev->mask, udev_device_get_devnode(dev));
- if (ev->mask & IN_CLOSE_WRITE) {
- char filename[UTIL_PATH_SIZE];
- int fd;
-
- log_debug("device %s closed, synthesising 'change'", udev_device_get_devnode(dev));
- strscpyl(filename, sizeof(filename), udev_device_get_syspath(dev), "/uevent", NULL);
- fd = open(filename, O_WRONLY|O_CLOEXEC);
- if (fd >= 0) {
- if (write(fd, "change", 6) < 0)
- log_debug("error writing uevent: %m");
- close(fd);
- }
- }
- if (ev->mask & IN_IGNORED)
- udev_watch_end(udev, dev);
+ if (!dev)
+ continue;
- udev_device_unref(dev);
- }
+ log_debug("inotify event: %x for %s", ev->mask, udev_device_get_devnode(dev));
+ if (ev->mask & IN_CLOSE_WRITE)
+ synthesize_change(dev);
+ else if (ev->mask & IN_IGNORED)
+ udev_watch_end(udev, dev);
+ udev_device_unref(dev);
}
free(buf);
~ianmdlvl / elogind.git / blobdiff