MNT_MONITOR_TYPE_USERSPACE
};
+struct monitor_opers;
+
struct monitor_entry {
- int fd; /* public file descriptor */
+ int fd; /* private entry file descriptor */
char *path; /* path to the monitored file */
int type; /* MNT_MONITOR_TYPE_* */
+ const struct monitor_opers *opers;
+
unsigned int enable : 1;
struct list_head ents;
struct libmnt_monitor {
int refcount;
+ int fd; /* public monitor file descriptor */
struct list_head ents;
};
+struct monitor_opers {
+ int (*op_get_fd)(struct libmnt_monitor *, struct monitor_entry *);
+ int (*op_verify_change)(struct libmnt_monitor *, struct monitor_entry *);
+};
+
static int monitor_enable_entry(struct libmnt_monitor *mn,
struct monitor_entry *me, int enable);
return NULL;
mn->refcount = 1;
+ mn->fd = -1;
INIT_LIST_HEAD(&mn->ents);
DBG(MONITOR, ul_debugobj(mn, "alloc"));
mn->refcount--;
if (mn->refcount <= 0) {
+ if (mn->fd >= 0)
+ close(mn->fd);
+
while (!list_empty(&mn->ents)) {
struct monitor_entry *me = list_entry(mn->ents.next,
struct monitor_entry, ents);
free_monitor_entry(me);
}
+
+ free(mn);
}
}
return me;
}
-static struct monitor_entry *monitor_get_entry(struct libmnt_monitor *mn, int type)
+static int monitor_next_entry(struct libmnt_monitor *mn,
+ struct libmnt_iter *itr,
+ struct monitor_entry **me)
{
- struct list_head *p;
+ int rc = 1;
assert(mn);
- assert(type);
+ assert(itr);
+ assert(me);
- list_for_each(p, &mn->ents) {
- struct monitor_entry *me;
+ if (!mn || !itr || !me)
+ return -EINVAL;
- me = list_entry(p, struct monitor_entry, ents);
- if (me->type == type)
- return me;
+ *me = NULL;
+
+ if (!itr->head)
+ MNT_ITER_INIT(itr, &mn->ents);
+ if (itr->p != itr->head) {
+ MNT_ITER_ITERATE(itr, *me, struct monitor_entry, ents);
+ rc = 0;
}
- return NULL;
+ return rc;
}
-static struct monitor_entry *monitor_get_entry_by_fd(struct libmnt_monitor *mn, int fd)
+static struct monitor_entry *monitor_get_entry(struct libmnt_monitor *mn, int type)
{
- struct list_head *p;
-
- assert(mn);
-
- if (fd < 0)
- return NULL;
-
- list_for_each(p, &mn->ents) {
- struct monitor_entry *me;
+ struct libmnt_iter itr;
+ struct monitor_entry *me;
- me = list_entry(p, struct monitor_entry, ents);
- if (me->fd == fd)
+ mnt_reset_iter(&itr, MNT_ITER_FORWARD);
+ while (monitor_next_entry(mn, &itr, &me) == 0) {
+ if (me->type == type)
return me;
}
-
- DBG(MONITOR, ul_debugobj(mn, "failed to get entry for fd=%d", fd));
return NULL;
}
-
-/**
- * mnt_monitor_enable_userspace:
- * @mn: monitor
- * @enable: 0 or 1
- * @filename: overwrites default
- *
- * Enables or disables userspace monitor. If the monitor does not exist and
- * enable=1 then allocates new resources necessary for the monitor.
- *
- * If high-level monitor has been already initialized (by mnt_monitor_get_fd()
- * or mnt_wait_monitor()) then it's updated according to @enable.
- *
- * The @filename is used only first time when you enable the monitor. It's
- * impossible to have more than one userspace monitor.
- *
- * Note that the current implementation of the userspace monitor is based on
- * inotify. On systems (libc) without inotify_init1() the function return
- * -ENOSYS. The dependence on inotify is implemenation specific and may be
- * changed later.
- *
- * Return: 0 on success and <0 on error
+/*
+ * Userspace monitor
*/
-int mnt_monitor_enable_userspace(struct libmnt_monitor *mn, int enable, const char *filename)
-{
- struct monitor_entry *me;
- int rc = 0;
-
- if (!mn)
- return -EINVAL;
-
- me = monitor_get_entry(mn, MNT_MONITOR_TYPE_USERSPACE);
- if (me)
- return monitor_enable_entry(mn, me, enable);
- if (!enable)
- return 0;
-
- DBG(MONITOR, ul_debugobj(mn, "allocate new userspace monitor"));
-
- /* create a new entry */
- if (!mnt_has_regular_mtab(&filename, NULL)) /* /etc/mtab */
- filename = mnt_get_utab_path(); /* /run/mount/utab */
- if (!filename) {
- DBG(MONITOR, ul_debugobj(mn, "failed to get userspace mount table path"));
- return -EINVAL;
- }
-
- me = monitor_new_entry(mn);
- if (!me)
- goto err;
-
- me->type = MNT_MONITOR_TYPE_USERSPACE;
- me->path = strdup(filename);
- if (!me->path)
- goto err;
- DBG(MONITOR, ul_debugobj(mn, "allocate new userspace monitor: OK"));
- return monitor_enable_entry(mn, me, 1);
-err:
- rc = -errno;
- free_monitor_entry(me);
- return rc;
-}
-
-/**
- * mnt_monitor_userspace_get_fd:
- * @mn: monitor pointer
- *
- * Returns: file descriptor to previously enabled userspace monitor or <0 on error.
- */
-#ifdef HAVE_INOTIFY_INIT1
-int mnt_monitor_userspace_get_fd(struct libmnt_monitor *mn)
+static int userspace_monitor_get_fd(struct libmnt_monitor *mn,
+ struct monitor_entry *me)
{
- struct monitor_entry *me;
int wd, rc;
char *dirname, *sep;
assert(mn);
+ assert(me);
- me = monitor_get_entry(mn, MNT_MONITOR_TYPE_USERSPACE);
if (!me || me->enable == 0) /* not-initialized or disabled */
return -EINVAL;
-
if (me->fd >= 0)
return me->fd; /* already initialized */
assert(me->path);
- DBG(MONITOR, ul_debugobj(mn, "open userspace monitor for %s", me->path));
+ DBG(MONITOR, ul_debugobj(mn, " open userspace monitor for %s", me->path));
dirname = me->path;
sep = stripoff_last_component(dirname); /* add \0 between dir/filename */
if (sep && sep > dirname)
*(sep - 1) = '/'; /* set '/' back to the path */
- DBG(MONITOR, ul_debugobj(mn, "new fd=%d", me->fd));
return me->fd;
err:
+ DBG(MONITOR, ul_debugobj(mn, "failed to create userspace monitor [rc=%d]", rc));
return -errno;
}
-static int monitor_userspace_is_changed(struct libmnt_monitor *mn,
- struct monitor_entry *me)
+static int userspace_monitor_verify_change(struct libmnt_monitor *mn,
+ struct monitor_entry *me)
{
char wanted[NAME_MAX + 1];
char buf[sizeof(struct inotify_event) + NAME_MAX + 1];
wanted[sizeof(wanted) - 1] = '\0';
rc = 0;
- DBG(MONITOR, ul_debugobj(mn, "wanted file: '%s'", wanted));
-
while ((r = read(me->fd, buf, sizeof(buf))) > 0) {
for (p = buf; p < buf + r; ) {
event = (struct inotify_event *) p;
return rc;
}
-#else /* HAVE_INOTIFY_INIT1 */
-int mnt_monitor_enable_userspace(
- struct libmnt_monitor *mn __attribute__((unused)),
- int enable __attribute__((unused)),
- const char *filename __attribute__((unused)))
-{
- return -ENOSYS;
-}
-int mnt_monitor_userspace_get_fd(
- struct libmnt_monitor *mn __attribute__((unused)))
+static const struct monitor_opers userspace_opers = {
+ .op_get_fd = userspace_monitor_get_fd,
+ .op_verify_change = userspace_monitor_verify_change
+};
+
+
+/**
+ * mnt_monitor_enable_userspace:
+ * @mn: monitor
+ * @enable: 0 or 1
+ * @filename: overwrites default
+ *
+ * Enables or disables userspace monitor. If the monitor does not exist and
+ * enable=1 then allocates new resources necessary for the monitor.
+ *
+ * If high-level monitor has been already initialized (by mnt_monitor_get_fd()
+ * or mnt_wait_monitor()) then it's updated according to @enable.
+ *
+ * The @filename is used only first time when you enable the monitor. It's
+ * impossible to have more than one userspace monitor.
+ *
+ * Return: 0 on success and <0 on error
+ */
+int mnt_monitor_enable_userspace(struct libmnt_monitor *mn, int enable, const char *filename)
{
- return -ENOSYS;
+ struct monitor_entry *me;
+ int rc = 0;
+
+ if (!mn)
+ return -EINVAL;
+
+ me = monitor_get_entry(mn, MNT_MONITOR_TYPE_USERSPACE);
+ if (me) {
+ rc = monitor_enable_entry(mn, me, enable);
+ if (!enable && me->fd) {
+ close(me->fd); /* disable inotify notification */
+ me->fd = -1;
+ }
+ return rc;
+ }
+ if (!enable)
+ return 0;
+
+ DBG(MONITOR, ul_debugobj(mn, "allocate new userspace monitor"));
+
+ /* create a new entry */
+ if (!mnt_has_regular_mtab(&filename, NULL)) /* /etc/mtab */
+ filename = mnt_get_utab_path(); /* /run/mount/utab */
+ if (!filename) {
+ DBG(MONITOR, ul_debugobj(mn, "failed to get userspace mount table path"));
+ return -EINVAL;
+ }
+
+ me = monitor_new_entry(mn);
+ if (!me)
+ goto err;
+
+ me->type = MNT_MONITOR_TYPE_USERSPACE;
+ me->opers = &userspace_opers;
+ me->path = strdup(filename);
+ if (!me->path)
+ goto err;
+
+ return monitor_enable_entry(mn, me, 1);
+err:
+ rc = -errno;
+ free_monitor_entry(me);
+ DBG(MONITOR, ul_debugobj(mn, "failed to allocate userspace monitor [rc=%d]", rc));
+ return rc;
}
-#endif
+
static int monitor_enable_entry(struct libmnt_monitor *mn,
struct monitor_entry *me, int enable)
return 0;
}
-/**
- * mnt_monitor_get_filename:
- * @mn: monitor
- * @fd: event file descriptor
- *
- * Returns: filename monitored by @fd or NULL on error.
- */
-const char *mnt_monitor_get_filename(struct libmnt_monitor *mn, int fd)
+int mnt_monitor_close_fd(struct libmnt_monitor *mn)
{
- struct monitor_entry *me = monitor_get_entry_by_fd(mn, fd);
+ if (mn && mn->fd >= 0) {
+ close(mn->fd);
+ mn->fd = -1;
+ }
- if (!me)
- return NULL;
- return me->path;
+ return 0;
}
-/**
- * mnt_monitor_is_changed:
- * @mn: monitor
- * @fd: event file descriptor
- *
- * Returns: 1 of the file monitored by @fd has been changed
- */
-int mnt_monitor_is_changed(struct libmnt_monitor *mn, int fd)
+int mnt_monitor_get_fd(struct libmnt_monitor *mn)
{
- struct monitor_entry *me = monitor_get_entry_by_fd(mn, fd);
+ struct libmnt_iter itr;
+ struct monitor_entry *me;
int rc = 0;
- if (!me)
- return 0;
+ if (!mn)
+ return -EINVAL;
+ if (mn->fd >= 0)
+ return mn->fd;
- switch (me->type) {
- case MNT_MONITOR_TYPE_USERSPACE:
- rc = monitor_userspace_is_changed(mn, me);
- break;
- default:
- return 0;
+ DBG(MONITOR, ul_debugobj(mn, "create top-level monitor fd"));
+ mn->fd = epoll_create1(EPOLL_CLOEXEC);
+ if (mn->fd < 0)
+ return -errno;
+
+ mnt_reset_iter(&itr, MNT_ITER_FORWARD);
+
+ DBG(MONITOR, ul_debugobj(mn, "adding monitor entries to epoll (fd=%d)", mn->fd));
+ while (monitor_next_entry(mn, &itr, &me) == 0) {
+ int fd;
+ struct epoll_event ev = { .events = EPOLLPRI | EPOLLIN };
+
+ if (!me->enable)
+ continue;
+
+ fd = me->opers->op_get_fd(mn, me);
+ if (fd < 0)
+ goto err;
+
+ DBG(MONITOR, ul_debugobj(mn, " add fd=%d (for %s)", fd, me->path));
+
+ ev.data.ptr = (void *) me;
+ if (epoll_ctl(mn->fd, EPOLL_CTL_ADD, fd, &ev) < 0)
+ goto err;
}
- DBG(MONITOR, ul_debugobj(mn, "fd=%d %s", me->fd, rc ? "changed" : "unchanged"));
+ DBG(MONITOR, ul_debugobj(mn, "successfully created monitor"));
+ return mn->fd;
+err:
+ rc = errno ? -errno : -EINVAL;
+ close(mn->fd);
+ mn->fd = -1;
+ DBG(MONITOR, ul_debugobj(mn, "failed to create monitor [rc=%d]", rc));
return rc;
}
+int mnt_monitor_next_changed(struct libmnt_monitor *mn,
+ const char **filename,
+ int *type)
+{
+ int rc;
+
+ if (!mn || mn->fd < 0)
+ return -EINVAL;
+
+ do {
+ struct monitor_entry *me;
+ struct epoll_event events[1];
+
+ rc = epoll_wait(mn->fd, events, 1, 0);
+ if (rc < 0)
+ return -errno; /* error */
+ if (rc == 0)
+ return 1; /* nothing */
+
+ me = (struct monitor_entry *) events[0].data.ptr;
+ if (!me)
+ continue;
+
+ if (me->opers->op_verify_change != NULL &&
+ me->opers->op_verify_change(mn, me) != 1)
+ continue; /* false positive */
+
+ if (filename)
+ *filename = me->path;
+ if (type)
+ *type = me->type;
+ return 0;
+ } while (1);
+
+ return 0;
+}
#ifdef TEST_PROGRAM
+/* monitor @fd by epoll */
static int my_epoll(struct libmnt_monitor *mn, int fd)
{
int efd = -1, rc = -1;
- struct epoll_event ev = { .events = 0 };
+ struct epoll_event ev;
assert(mn);
assert(fd >= 0);
printf("waiting for changes...\n");
do {
+ const char *filename = NULL;
struct epoll_event events[1];
- int n, nfds = epoll_wait(efd, events, 1, -1);
+ int n = epoll_wait(efd, events, 1, -1);
- if (nfds < 0) {
+ if (n < 0) {
rc = -errno;
warn("polling error");
goto done;
}
+ if (n == 0 || events[0].data.fd != fd)
+ continue;
- for (n = 0; n < nfds; n++) {
- if (events[n].data.fd == fd &&
- mnt_monitor_is_changed(mn, fd) == 1)
- printf("%s: change detected\n",
- mnt_monitor_get_filename(mn, fd));
- }
+ while (mnt_monitor_next_changed(mn, &filename, NULL) == 0)
+ printf("%s: change detected\n", filename);
} while (1);
rc = 0;
return rc;
}
-int test_low_user(struct libmnt_test *ts, int argc, char *argv[])
+/*
+ * create a monitor and add the monitor fd to epoll
+ */
+int test_epoll(struct libmnt_test *ts, int argc, char *argv[])
{
struct libmnt_monitor *mn;
- int fd, rc = -1;
+ int i, fd, rc = -1;
mn = mnt_new_monitor();
if (!mn) {
goto done;
}
- if (mnt_monitor_enable_userspace(mn, TRUE, NULL)) {
- warn("failed to initialize userspace monitor");
- goto done;
+ for (i = 1; i < argc; i++) {
+ if (strcmp(argv[i], "userspace") == 0) {
+ if (mnt_monitor_enable_userspace(mn, TRUE, NULL)) {
+ warn("failed to initialize userspace monitor");
+ goto done;
+ }
+ }
}
- fd = mnt_monitor_userspace_get_fd(mn);
+ fd = mnt_monitor_get_fd(mn);
if (fd < 0) {
- warn("failed to initialize userspace monitor fd");
+ warn("failed to initialize monitor fd");
goto done;
}
int main(int argc, char *argv[])
{
struct libmnt_test tss[] = {
- { "--low-userspace", test_low_user, "tests low-level userspace monitor" },
+ { "--epoll", test_epoll, "<userspace kernel ...> test monitor in epoll" },
{ NULL }
};
projects / thirdparty / util-linux.git / commitdiff
