lib_mount_sources += '''
src/hooks.c
src/monitor.c
+ src/monitor.h
+ src/monitor_utab.c
+ src/monitor_mountinfo.c
src/optlist.c
src/hook_veritydev.c
src/hook_subdir.c
libmount/src/hook_idmap.c \
libmount/src/hook_loopdev.c \
libmount/src/hook_veritydev.c \
- libmount/src/monitor.c
+ libmount/src/monitor.c \
+ libmount/src/monitor.h \
+ libmount/src/monitor_utab.c \
+ libmount/src/monitor_mountinfo.c
if HAVE_BTRFS
libmount_la_SOURCES += libmount/src/btrfs.c
test_mount_tab_diff_LDFLAGS = $(libmount_tests_ldflags)
test_mount_tab_diff_LDADD = $(libmount_tests_ldadd)
-test_mount_monitor_SOURCES = libmount/src/monitor.c
+test_mount_monitor_SOURCES = libmount/src/monitor.c \
+ libmount/src/monitor.h \
+ libmount/src/monitor_utab.c \
+ libmount/src/monitor_mountinfo.c
test_mount_monitor_CFLAGS = $(libmount_tests_cflags)
test_mount_monitor_LDFLAGS = $(libmount_tests_ldflags)
test_mount_monitor_LDADD = $(libmount_tests_ldadd)
*
*/
-#include "fileutils.h"
#include "mountP.h"
-#include "pathnames.h"
+#include "monitor.h"
-#include <sys/inotify.h>
#include <sys/epoll.h>
-
-struct monitor_opers;
-
-struct monitor_entry {
- int fd; /* private entry file descriptor */
- char *path; /* path to the monitored file */
- int type; /* MNT_MONITOR_TYPE_* */
- uint32_t events; /* wanted epoll events */
-
- const struct monitor_opers *opers;
-
- unsigned int enable : 1,
- changed : 1;
-
- struct list_head ents;
-};
-
-struct libmnt_monitor {
- int refcount;
- int fd; /* public monitor file descriptor */
-
- struct list_head ents;
-
- unsigned int kernel_veiled: 1;
-};
-
-struct monitor_opers {
- int (*op_get_fd)(struct libmnt_monitor *, struct monitor_entry *);
- int (*op_close_fd)(struct libmnt_monitor *, struct monitor_entry *);
- int (*op_event_verify)(struct libmnt_monitor *, struct monitor_entry *);
-};
-
-static int monitor_modify_epoll(struct libmnt_monitor *mn,
- struct monitor_entry *me, int enable);
-
/**
* mnt_new_monitor:
*
mn->refcount++;
}
-static void free_monitor_entry(struct monitor_entry *me)
+void free_monitor_entry(struct monitor_entry *me)
{
if (!me)
return;
}
}
-static struct monitor_entry *monitor_new_entry(struct libmnt_monitor *mn)
+struct monitor_entry *monitor_new_entry(struct libmnt_monitor *mn)
{
struct monitor_entry *me;
}
/* returns entry by type */
-static struct monitor_entry *monitor_get_entry(struct libmnt_monitor *mn, int type)
+struct monitor_entry *monitor_get_entry(struct libmnt_monitor *mn, int type)
{
struct libmnt_iter itr;
struct monitor_entry *me;
}
-/*
- * Userspace monitor
- */
-
-static int userspace_monitor_close_fd(struct libmnt_monitor *mn __attribute__((__unused__)),
- struct monitor_entry *me)
-{
- assert(me);
-
- if (me->fd >= 0)
- close(me->fd);
- me->fd = -1;
- return 0;
-}
-
-static int userspace_add_watch(struct monitor_entry *me, int *final, int *fd)
-{
- char *filename = NULL;
- int wd, rc = -EINVAL;
-
- assert(me);
- assert(me->path);
-
- /*
- * libmount uses utab.event file to monitor and control utab updates
- */
- if (asprintf(&filename, "%s.event", me->path) <= 0) {
- rc = -ENOMEM;
- goto done;
- }
-
- /* try event file if already exists */
- errno = 0;
- wd = inotify_add_watch(me->fd, filename, IN_CLOSE_WRITE);
- if (wd >= 0) {
- DBG(MONITOR, ul_debug(" added inotify watch for %s [fd=%d]", filename, wd));
- rc = 0;
- if (final)
- *final = 1;
- if (fd)
- *fd = wd;
- goto done;
- } else if (errno != ENOENT) {
- rc = -errno;
- goto done;
- }
-
- while (strchr(filename, '/')) {
- stripoff_last_component(filename);
- if (!*filename)
- break;
-
- /* try directory where is the event file */
- errno = 0;
- wd = inotify_add_watch(me->fd, filename, IN_CREATE|IN_ISDIR);
- if (wd >= 0) {
- DBG(MONITOR, ul_debug(" added inotify watch for %s [fd=%d]", filename, wd));
- rc = 0;
- if (fd)
- *fd = wd;
- break;
- }
-
- if (errno != ENOENT) {
- rc = -errno;
- break;
- }
- }
-done:
- free(filename);
- return rc;
-}
-
-static int userspace_monitor_get_fd(struct libmnt_monitor *mn,
- struct monitor_entry *me)
-{
- int rc;
-
- 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));
-
- me->fd = inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
- if (me->fd < 0)
- goto err;
-
- if (userspace_add_watch(me, NULL, NULL) < 0)
- goto err;
-
- return me->fd;
-err:
- rc = -errno;
- if (me->fd >= 0)
- close(me->fd);
- me->fd = -1;
- DBG(MONITOR, ul_debugobj(mn, "failed to create userspace monitor [rc=%d]", rc));
- return rc;
-}
-
-/*
- * verify and drain inotify buffer
- */
-static int userspace_event_verify(struct libmnt_monitor *mn,
- struct monitor_entry *me)
-{
- char buf[sizeof(struct inotify_event) + NAME_MAX + 1];
- int status = 0;
-
- if (!me || me->fd < 0)
- return 0;
-
- DBG(MONITOR, ul_debugobj(mn, "drain and verify userspace monitor inotify"));
-
- /* the me->fd is non-blocking */
- do {
- ssize_t len;
- char *p;
- const struct inotify_event *e;
-
- len = read(me->fd, buf, sizeof(buf));
- if (len < 0)
- break;
-
- for (p = buf; p < buf + len;
- p += sizeof(struct inotify_event) + e->len) {
-
- int fd = -1;
-
- e = (const struct inotify_event *) p;
- DBG(MONITOR, ul_debugobj(mn, " inotify event 0x%x [%s]\n", e->mask, e->len ? e->name : ""));
-
- if (e->mask & IN_CLOSE_WRITE)
- status = 1;
- else {
- /* add watch for the event file */
- userspace_add_watch(me, &status, &fd);
-
- if (fd != e->wd) {
- DBG(MONITOR, ul_debugobj(mn, " removing watch [fd=%d]", e->wd));
- inotify_rm_watch(me->fd, e->wd);
- }
- }
- }
- } while (1);
-
- DBG(MONITOR, ul_debugobj(mn, "%s", status == 1 ? " success" : " nothing"));
- return status;
-}
-
-/*
- * userspace monitor operations
- */
-static const struct monitor_opers userspace_opers = {
- .op_get_fd = userspace_monitor_get_fd,
- .op_close_fd = userspace_monitor_close_fd,
- .op_event_verify = userspace_event_verify
-};
-
-/**
- * mnt_monitor_enable_userspace:
- * @mn: monitor
- * @enable: 0 or 1
- * @filename: overwrites default
- *
- * Enables or disables userspace monitoring. If the userspace monitor does not
- * exist and enable=1 then allocates new resources necessary for the monitor.
- *
- * If the top-level monitor has been already created (by mnt_monitor_get_fd()
- * or mnt_monitor_wait()) then it's updated according to @enable.
- *
- * The @filename is used only the first time when you enable the monitor. It's
- * impossible to have more than one userspace monitor. The recommended is to
- * use NULL as filename.
- *
- * The userspace monitor is unsupported for systems with classic regular
- * /etc/mtab file.
- *
- * Return: 0 on success and <0 on error
- */
-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) {
- rc = monitor_modify_epoll(mn, me, enable);
- if (!enable)
- userspace_monitor_close_fd(mn, me);
- return rc;
- }
- if (!enable)
- return 0;
-
- DBG(MONITOR, ul_debugobj(mn, "allocate new userspace monitor"));
-
- if (!filename)
- 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->events = EPOLLIN;
- me->path = strdup(filename);
- if (!me->path)
- goto err;
-
- return monitor_modify_epoll(mn, me, TRUE);
-err:
- rc = -errno;
- free_monitor_entry(me);
- DBG(MONITOR, ul_debugobj(mn, "failed to allocate userspace monitor [rc=%d]", rc));
- return rc;
-}
-
-
-/*
- * Kernel monitor
- */
-
-static int kernel_monitor_close_fd(struct libmnt_monitor *mn __attribute__((__unused__)),
- struct monitor_entry *me)
-{
- assert(me);
-
- if (me->fd >= 0)
- close(me->fd);
- me->fd = -1;
- return 0;
-}
-
-static int kernel_monitor_get_fd(struct libmnt_monitor *mn,
- struct monitor_entry *me)
-{
- int rc;
-
- 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 kernel monitor for %s", me->path));
-
- me->fd = open(me->path, O_RDONLY|O_CLOEXEC);
- if (me->fd < 0)
- goto err;
-
- return me->fd;
-err:
- rc = -errno;
- DBG(MONITOR, ul_debugobj(mn, "failed to create kernel monitor [rc=%d]", rc));
- return rc;
-}
-
-static int kernel_event_verify(struct libmnt_monitor *mn,
- struct monitor_entry *me)
-{
- int status = 1;
-
- if (!mn || !me || me->fd < 0)
- return 0;
-
- if (mn->kernel_veiled && access(MNT_PATH_UTAB ".act", F_OK) == 0) {
- status = 0;
- DBG(MONITOR, ul_debugobj(mn, "kernel event veiled"));
- }
- return status;
-}
-
-/*
- * kernel monitor operations
- */
-static const struct monitor_opers kernel_opers = {
- .op_get_fd = kernel_monitor_get_fd,
- .op_close_fd = kernel_monitor_close_fd,
- .op_event_verify = kernel_event_verify
-};
-
-/**
- * mnt_monitor_enable_kernel:
- * @mn: monitor
- * @enable: 0 or 1
- *
- * Enables or disables kernel VFS monitoring. If the monitor does not exist and
- * enable=1 then allocates new resources necessary for the monitor.
- *
- * If the top-level monitor has been already created (by mnt_monitor_get_fd()
- * or mnt_monitor_wait()) then it's updated according to @enable.
- *
- * Return: 0 on success and <0 on error
- */
-int mnt_monitor_enable_kernel(struct libmnt_monitor *mn, int enable)
-{
- struct monitor_entry *me;
- int rc = 0;
-
- if (!mn)
- return -EINVAL;
-
- me = monitor_get_entry(mn, MNT_MONITOR_TYPE_KERNEL);
- if (me) {
- rc = monitor_modify_epoll(mn, me, enable);
- if (!enable)
- kernel_monitor_close_fd(mn, me);
- return rc;
- }
- if (!enable)
- return 0;
-
- DBG(MONITOR, ul_debugobj(mn, "allocate new kernel monitor"));
-
- /* create a new entry */
- me = monitor_new_entry(mn);
- if (!me)
- goto err;
-
- /* If you want to use epoll FD in another epoll then top level
- * epoll_wait() will drain all events from low-level FD if the
- * low-level FD is not added with EPOLLIN. It means without EPOLLIN it
- * it's impossible to detect which low-level FD has been active.
- *
- * Unfortunately, use EPOLLIN for mountinfo is tricky because in this
- * case kernel returns events all time (we don't read from the FD).
- * The solution is to use also edge-triggered (EPOLLET) flag, then
- * kernel generate events on mountinfo changes only. The disadvantage is
- * that we have to drain initial event generated by EPOLLIN after
- * epoll_ctl(ADD). See monitor_modify_epoll().
- */
- me->events = EPOLLIN | EPOLLET;
-
- me->type = MNT_MONITOR_TYPE_KERNEL;
- me->opers = &kernel_opers;
- me->path = strdup(_PATH_PROC_MOUNTINFO);
- if (!me->path)
- goto err;
-
- return monitor_modify_epoll(mn, me, TRUE);
-err:
- rc = -errno;
- free_monitor_entry(me);
- DBG(MONITOR, ul_debugobj(mn, "failed to allocate kernel monitor [rc=%d]", rc));
- return rc;
-}
-
-/**
- * mnt_monitor_veil_kernel:
- * @mn: monitor instance
- * @enable: 1 or 0
- *
- * Force monitor to ignore kernel events if the same mount/umount operation
- * will generate an userspace event later. The kernel-only mount operation will
- * be not affected.
- *
- * Return: 0 on success and <0 on error.
- *
- * Since: 2.40
- */
-int mnt_monitor_veil_kernel(struct libmnt_monitor *mn, int enable)
-{
- if (!mn)
- return -EINVAL;
-
- mn->kernel_veiled = enable ? 1 : 0;
- return 0;
-}
-
/*
* Add/Remove monitor entry to/from monitor epoll.
*/
-static int monitor_modify_epoll(struct libmnt_monitor *mn,
+int monitor_modify_epoll(struct libmnt_monitor *mn,
struct monitor_entry *me, int enable)
{
assert(mn);
--- /dev/null
+
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+
+#ifndef _MNTMONITOR_PRIVATE_H
+#define _MNTMONITOR_PRIVATE_H
+
+struct monitor_opers;
+
+struct monitor_entry {
+ int fd; /* private entry file descriptor */
+ char *path; /* path to the monitored file */
+ int type; /* MNT_MONITOR_TYPE_* */
+ uint32_t events; /* wanted epoll events */
+
+ const struct monitor_opers *opers;
+
+ unsigned int enable : 1,
+ changed : 1;
+
+ struct list_head ents;
+};
+
+struct libmnt_monitor {
+ int refcount;
+ int fd; /* public monitor file descriptor */
+
+ struct list_head ents;
+
+ unsigned int kernel_veiled: 1;
+};
+
+struct monitor_opers {
+ int (*op_get_fd)(struct libmnt_monitor *, struct monitor_entry *);
+ int (*op_close_fd)(struct libmnt_monitor *, struct monitor_entry *);
+ int (*op_event_verify)(struct libmnt_monitor *, struct monitor_entry *);
+};
+
+int monitor_modify_epoll(struct libmnt_monitor *mn, struct monitor_entry *me, int enable);
+struct monitor_entry *monitor_get_entry(struct libmnt_monitor *mn, int type);
+struct monitor_entry *monitor_new_entry(struct libmnt_monitor *mn);
+void free_monitor_entry(struct monitor_entry *me);
+
+#endif /* _MNTMONITOR_PRIVATE_H */
--- /dev/null
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * This file is part of libmount from util-linux project.
+ *
+ * Copyright (C) 2014-2025 Karel Zak <kzak@redhat.com>
+ *
+ * libmount is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ * libmount kernel mount table monitor (based on /proc/self/mountinfo epoll)
+ */
+
+#include "mountP.h"
+#include "monitor.h"
+
+#include "pathnames.h"
+
+#include <sys/epoll.h>
+
+static int kernel_monitor_close_fd(struct libmnt_monitor *mn __attribute__((__unused__)),
+ struct monitor_entry *me)
+{
+ assert(me);
+
+ if (me->fd >= 0)
+ close(me->fd);
+ me->fd = -1;
+ return 0;
+}
+
+static int kernel_monitor_get_fd(struct libmnt_monitor *mn,
+ struct monitor_entry *me)
+{
+ int rc;
+
+ 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 kernel monitor for %s", me->path));
+
+ me->fd = open(me->path, O_RDONLY|O_CLOEXEC);
+ if (me->fd < 0)
+ goto err;
+
+ return me->fd;
+err:
+ rc = -errno;
+ DBG(MONITOR, ul_debugobj(mn, "failed to create kernel monitor [rc=%d]", rc));
+ return rc;
+}
+
+static int kernel_event_verify(struct libmnt_monitor *mn,
+ struct monitor_entry *me)
+{
+ int status = 1;
+
+ if (!mn || !me || me->fd < 0)
+ return 0;
+
+ if (mn->kernel_veiled && access(MNT_PATH_UTAB ".act", F_OK) == 0) {
+ status = 0;
+ DBG(MONITOR, ul_debugobj(mn, "kernel event veiled"));
+ }
+ return status;
+}
+
+/*
+ * kernel monitor operations
+ */
+static const struct monitor_opers kernel_opers = {
+ .op_get_fd = kernel_monitor_get_fd,
+ .op_close_fd = kernel_monitor_close_fd,
+ .op_event_verify = kernel_event_verify
+};
+
+/**
+ * mnt_monitor_enable_kernel:
+ * @mn: monitor
+ * @enable: 0 or 1
+ *
+ * Enables or disables kernel VFS monitoring. If the monitor does not exist and
+ * enable=1 then allocates new resources necessary for the monitor.
+ *
+ * If the top-level monitor has been already created (by mnt_monitor_get_fd()
+ * or mnt_monitor_wait()) then it's updated according to @enable.
+ *
+ * Return: 0 on success and <0 on error
+ */
+int mnt_monitor_enable_kernel(struct libmnt_monitor *mn, int enable)
+{
+ struct monitor_entry *me;
+ int rc = 0;
+
+ if (!mn)
+ return -EINVAL;
+
+ me = monitor_get_entry(mn, MNT_MONITOR_TYPE_KERNEL);
+ if (me) {
+ rc = monitor_modify_epoll(mn, me, enable);
+ if (!enable)
+ kernel_monitor_close_fd(mn, me);
+ return rc;
+ }
+ if (!enable)
+ return 0;
+
+ DBG(MONITOR, ul_debugobj(mn, "allocate new kernel monitor"));
+
+ /* create a new entry */
+ me = monitor_new_entry(mn);
+ if (!me)
+ goto err;
+
+ /* If you want to use epoll FD in another epoll then top level
+ * epoll_wait() will drain all events from low-level FD if the
+ * low-level FD is not added with EPOLLIN. It means without EPOLLIN it
+ * it's impossible to detect which low-level FD has been active.
+ *
+ * Unfortunately, use EPOLLIN for mountinfo is tricky because in this
+ * case kernel returns events all time (we don't read from the FD).
+ * The solution is to use also edge-triggered (EPOLLET) flag, then
+ * kernel generate events on mountinfo changes only. The disadvantage is
+ * that we have to drain initial event generated by EPOLLIN after
+ * epoll_ctl(ADD). See monitor_modify_epoll().
+ */
+ me->events = EPOLLIN | EPOLLET;
+
+ me->type = MNT_MONITOR_TYPE_KERNEL;
+ me->opers = &kernel_opers;
+ me->path = strdup(_PATH_PROC_MOUNTINFO);
+ if (!me->path)
+ goto err;
+
+ return monitor_modify_epoll(mn, me, TRUE);
+err:
+ rc = -errno;
+ free_monitor_entry(me);
+ DBG(MONITOR, ul_debugobj(mn, "failed to allocate kernel monitor [rc=%d]", rc));
+ return rc;
+}
+
+/**
+ * mnt_monitor_veil_kernel:
+ * @mn: monitor instance
+ * @enable: 1 or 0
+ *
+ * Force monitor to ignore kernel events if the same mount/umount operation
+ * will generate an userspace event later. The kernel-only mount operation will
+ * be not affected.
+ *
+ * Return: 0 on success and <0 on error.
+ *
+ * Since: 2.40
+ */
+int mnt_monitor_veil_kernel(struct libmnt_monitor *mn, int enable)
+{
+ if (!mn)
+ return -EINVAL;
+
+ mn->kernel_veiled = enable ? 1 : 0;
+ return 0;
+}
--- /dev/null
+/* SPDX-License-Identifier: LGPL-2.1-or-later */
+/*
+ * This file is part of libmount from util-linux project.
+ *
+ * Copyright (C) 2014-2025 Karel Zak <kzak@redhat.com>
+ *
+ * libmount is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation; either version 2.1 of the License, or
+ * (at your option) any later version.
+ *
+ *
+ * libmount userspace monitor (based on /run/mount/utab inotify)
+ */
+
+#include "mountP.h"
+#include "monitor.h"
+
+#include "fileutils.h"
+
+#include <sys/inotify.h>
+#include <sys/epoll.h>
+
+static int userspace_monitor_close_fd(
+ struct libmnt_monitor *mn __attribute__((__unused__)),
+ struct monitor_entry *me)
+{
+ assert(me);
+
+ if (me->fd >= 0)
+ close(me->fd);
+ me->fd = -1;
+ return 0;
+}
+
+static int userspace_add_watch(struct monitor_entry *me, int *final, int *fd)
+{
+ char *filename = NULL;
+ int wd, rc = -EINVAL;
+
+ assert(me);
+ assert(me->path);
+
+ /*
+ * libmount uses utab.event file to monitor and control utab updates
+ */
+ if (asprintf(&filename, "%s.event", me->path) <= 0) {
+ rc = -ENOMEM;
+ goto done;
+ }
+
+ /* try event file if already exists */
+ errno = 0;
+ wd = inotify_add_watch(me->fd, filename, IN_CLOSE_WRITE);
+ if (wd >= 0) {
+ DBG(MONITOR, ul_debug(" added inotify watch for %s [fd=%d]", filename, wd));
+ rc = 0;
+ if (final)
+ *final = 1;
+ if (fd)
+ *fd = wd;
+ goto done;
+ } else if (errno != ENOENT) {
+ rc = -errno;
+ goto done;
+ }
+
+ while (strchr(filename, '/')) {
+ stripoff_last_component(filename);
+ if (!*filename)
+ break;
+
+ /* try directory where is the event file */
+ errno = 0;
+ wd = inotify_add_watch(me->fd, filename, IN_CREATE|IN_ISDIR);
+ if (wd >= 0) {
+ DBG(MONITOR, ul_debug(" added inotify watch for %s [fd=%d]", filename, wd));
+ rc = 0;
+ if (fd)
+ *fd = wd;
+ break;
+ }
+
+ if (errno != ENOENT) {
+ rc = -errno;
+ break;
+ }
+ }
+done:
+ free(filename);
+ return rc;
+}
+
+static int userspace_monitor_get_fd(struct libmnt_monitor *mn,
+ struct monitor_entry *me)
+{
+ int rc;
+
+ 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));
+
+ me->fd = inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
+ if (me->fd < 0)
+ goto err;
+
+ if (userspace_add_watch(me, NULL, NULL) < 0)
+ goto err;
+
+ return me->fd;
+err:
+ rc = -errno;
+ if (me->fd >= 0)
+ close(me->fd);
+ me->fd = -1;
+ DBG(MONITOR, ul_debugobj(mn, "failed to create userspace monitor [rc=%d]", rc));
+ return rc;
+}
+
+/*
+ * verify and drain inotify buffer
+ */
+static int userspace_event_verify(struct libmnt_monitor *mn,
+ struct monitor_entry *me)
+{
+ char buf[sizeof(struct inotify_event) + NAME_MAX + 1];
+ int status = 0;
+
+ if (!me || me->fd < 0)
+ return 0;
+
+ DBG(MONITOR, ul_debugobj(mn, "drain and verify userspace monitor inotify"));
+
+ /* the me->fd is non-blocking */
+ do {
+ ssize_t len;
+ char *p;
+ const struct inotify_event *e;
+
+ len = read(me->fd, buf, sizeof(buf));
+ if (len < 0)
+ break;
+
+ for (p = buf; p < buf + len;
+ p += sizeof(struct inotify_event) + e->len) {
+
+ int fd = -1;
+
+ e = (const struct inotify_event *) p;
+ DBG(MONITOR, ul_debugobj(mn, " inotify event 0x%x [%s]\n", e->mask, e->len ? e->name : ""));
+
+ if (e->mask & IN_CLOSE_WRITE)
+ status = 1;
+ else {
+ /* add watch for the event file */
+ userspace_add_watch(me, &status, &fd);
+
+ if (fd != e->wd) {
+ DBG(MONITOR, ul_debugobj(mn, " removing watch [fd=%d]", e->wd));
+ inotify_rm_watch(me->fd, e->wd);
+ }
+ }
+ }
+ } while (1);
+
+ DBG(MONITOR, ul_debugobj(mn, "%s", status == 1 ? " success" : " nothing"));
+ return status;
+}
+
+/*
+ * userspace monitor operations
+ */
+static const struct monitor_opers userspace_opers = {
+ .op_get_fd = userspace_monitor_get_fd,
+ .op_close_fd = userspace_monitor_close_fd,
+ .op_event_verify = userspace_event_verify
+};
+
+/**
+ * mnt_monitor_enable_userspace:
+ * @mn: monitor
+ * @enable: 0 or 1
+ * @filename: overwrites default
+ *
+ * Enables or disables userspace monitoring. If the userspace monitor does not
+ * exist and enable=1 then allocates new resources necessary for the monitor.
+ *
+ * If the top-level monitor has been already created (by mnt_monitor_get_fd()
+ * or mnt_monitor_wait()) then it's updated according to @enable.
+ *
+ * The @filename is used only the first time when you enable the monitor. It's
+ * impossible to have more than one userspace monitor. The recommended is to
+ * use NULL as filename.
+ *
+ * The userspace monitor is unsupported for systems with classic regular
+ * /etc/mtab file.
+ *
+ * Return: 0 on success and <0 on error
+ */
+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) {
+ rc = monitor_modify_epoll(mn, me, enable);
+ if (!enable)
+ userspace_monitor_close_fd(mn, me);
+ return rc;
+ }
+ if (!enable)
+ return 0;
+
+ DBG(MONITOR, ul_debugobj(mn, "allocate new userspace monitor"));
+
+ if (!filename)
+ 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->events = EPOLLIN;
+ me->path = strdup(filename);
+ if (!me->path)
+ goto err;
+
+ return monitor_modify_epoll(mn, me, TRUE);
+err:
+ rc = -errno;
+ free_monitor_entry(me);
+ DBG(MONITOR, ul_debugobj(mn, "failed to allocate userspace monitor [rc=%d]", rc));
+ return rc;
+}
projects / thirdparty / util-linux.git / commitdiff
