noinst_LTLIBRARIES = libfd-tracker.la
-libfd_tracker_la_SOURCES = fd-tracker.h fd-tracker.c \
- utils.h utils.c \
- inode.h inode.c \
- utils-poll.c
+libfd_tracker_la_SOURCES = \
+ fd-tracker.cpp \
+ fd-tracker.h \
+ inode.cpp \
+ inode.h \
+ utils.cpp \
+ utils.h \
+ utils-poll.cpp
+++ /dev/null
-/*
- * Copyright (C) 2018-2020 Jérémie Galarneau <jeremie.galarneau@efficios.com>
- *
- * SPDX-License-Identifier: GPL-2.0-only
- *
- */
-
-#include <urcu.h>
-#include <urcu/list.h>
-#include <urcu/rculfhash.h>
-
-#include <fcntl.h>
-#include <inttypes.h>
-#include <pthread.h>
-#include <stdbool.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-
-#include <common/defaults.h>
-#include <common/error.h>
-#include <common/fs-handle-internal.h>
-#include <common/hashtable/hashtable.h>
-#include <common/hashtable/utils.h>
-#include <common/macros.h>
-#include <common/optional.h>
-
-#include "fd-tracker.h"
-#include "inode.h"
-
-/* Tracker lock must be taken by the user. */
-#define TRACKED_COUNT(tracker) \
- (tracker->count.suspendable.active + \
- tracker->count.suspendable.suspended + \
- tracker->count.unsuspendable)
-
-/* Tracker lock must be taken by the user. */
-#define ACTIVE_COUNT(tracker) \
- (tracker->count.suspendable.active + tracker->count.unsuspendable)
-
-/* Tracker lock must be taken by the user. */
-#define SUSPENDED_COUNT(tracker) (tracker->count.suspendable.suspended)
-
-/* Tracker lock must be taken by the user. */
-#define SUSPENDABLE_COUNT(tracker) \
- (tracker->count.suspendable.active + \
- tracker->count.suspendable.suspended)
-
-/* Tracker lock must be taken by the user. */
-#define UNSUSPENDABLE_COUNT(tracker) (tracker->count.unsuspendable)
-
-struct fd_tracker {
- pthread_mutex_t lock;
- struct {
- struct {
- unsigned int active;
- unsigned int suspended;
- } suspendable;
- unsigned int unsuspendable;
- } count;
- unsigned int capacity;
- struct {
- uint64_t uses;
- uint64_t misses;
- /* Failures to suspend or restore fs handles. */
- uint64_t errors;
- } stats;
- /*
- * The head of the active_handles list is always the least recently
- * used active handle. When an handle is used, it is removed from the
- * list and added to the end. When a file has to be suspended, the
- * first element in the list is "popped", suspended, and added to the
- * list of suspended handles.
- */
- struct cds_list_head active_handles;
- struct cds_list_head suspended_handles;
- struct cds_lfht *unsuspendable_fds;
- struct lttng_inode_registry *inode_registry;
- /* Unlinked files are moved in this directory under a unique name. */
- struct lttng_directory_handle *unlink_directory_handle;
- struct lttng_unlinked_file_pool *unlinked_file_pool;
-};
-
-struct open_properties {
- int flags;
- LTTNG_OPTIONAL(mode_t) mode;
-};
-
-/*
- * A fs_handle_tracked is not ref-counted. Therefore, it is assumed that a
- * handle is never in-use while it is being reclaimed. It can be
- * shared by multiple threads, but external synchronization is required
- * to ensure it is not still being used when it is reclaimed (close method).
- * In this respect, it is not different from a regular file descriptor.
- *
- * The fs_handle lock always nests _within_ the tracker's lock.
- */
-struct fs_handle_tracked {
- struct fs_handle parent;
- pthread_mutex_t lock;
- /*
- * Weak reference to the tracker. All fs_handles are assumed to have
- * been closed at the moment of the destruction of the fd_tracker.
- */
- struct fd_tracker *tracker;
- struct open_properties properties;
- struct lttng_inode *inode;
- int fd;
- /* inode number of the file at the time of the handle's creation. */
- uint64_t ino;
- bool in_use;
- /* Offset to which the file should be restored. */
- off_t offset;
- struct cds_list_head handles_list_node;
-};
-
-struct unsuspendable_fd {
- /*
- * Accesses are only performed through the tracker, which is protected
- * by its own lock.
- */
- int fd;
- char *name;
- struct cds_lfht_node tracker_node;
- struct rcu_head rcu_head;
-};
-
-static struct {
- pthread_mutex_t lock;
- bool initialized;
- unsigned long value;
-} seed = {
- .lock = PTHREAD_MUTEX_INITIALIZER,
-};
-
-static int match_fd(struct cds_lfht_node *node, const void *key);
-static void unsuspendable_fd_destroy(struct unsuspendable_fd *entry);
-static struct unsuspendable_fd *unsuspendable_fd_create(
- const char *name, int fd);
-static int open_from_properties(const struct lttng_directory_handle *dir_handle,
- const char *path, struct open_properties *properties);
-
-static void fs_handle_tracked_log(struct fs_handle_tracked *handle);
-static int fs_handle_tracked_suspend(struct fs_handle_tracked *handle);
-static int fs_handle_tracked_restore(struct fs_handle_tracked *handle);
-static int fs_handle_tracked_get_fd(struct fs_handle *_handle);
-static void fs_handle_tracked_put_fd(struct fs_handle *_handle);
-static int fs_handle_tracked_unlink(struct fs_handle *_handle);
-static int fs_handle_tracked_close(struct fs_handle *_handle);
-
-static void fd_tracker_track(
- struct fd_tracker *tracker, struct fs_handle_tracked *handle);
-static void fd_tracker_untrack(
- struct fd_tracker *tracker, struct fs_handle_tracked *handle);
-static int fd_tracker_suspend_handles(
- struct fd_tracker *tracker, unsigned int count);
-static int fd_tracker_restore_handle(
- struct fd_tracker *tracker, struct fs_handle_tracked *handle);
-
-/* Match function of the tracker's unsuspendable_fds hash table. */
-static int match_fd(struct cds_lfht_node *node, const void *key)
-{
- struct unsuspendable_fd *entry = caa_container_of(
- node, struct unsuspendable_fd, tracker_node);
-
- return hash_match_key_ulong(
- (void *) (unsigned long) entry->fd, (void *) key);
-}
-
-static void delete_unsuspendable_fd(struct rcu_head *head)
-{
- struct unsuspendable_fd *fd = caa_container_of(
- head, struct unsuspendable_fd, rcu_head);
-
- free(fd->name);
- free(fd);
-}
-
-static void unsuspendable_fd_destroy(struct unsuspendable_fd *entry)
-{
- if (!entry) {
- return;
- }
- call_rcu(&entry->rcu_head, delete_unsuspendable_fd);
-}
-
-static struct unsuspendable_fd *unsuspendable_fd_create(
- const char *name, int fd)
-{
- struct unsuspendable_fd *entry = zmalloc(sizeof(*entry));
-
- if (!entry) {
- goto error;
- }
- if (name) {
- entry->name = strdup(name);
- if (!entry->name) {
- goto error;
- }
- }
- cds_lfht_node_init(&entry->tracker_node);
- entry->fd = fd;
- return entry;
-error:
- unsuspendable_fd_destroy(entry);
- return NULL;
-}
-
-static void fs_handle_tracked_log(struct fs_handle_tracked *handle)
-{
- const char *path;
-
- pthread_mutex_lock(&handle->lock);
- lttng_inode_borrow_location(handle->inode, NULL, &path);
-
- if (handle->fd >= 0) {
- DBG_NO_LOC(" %s [active, fd %d%s]", path, handle->fd,
- handle->in_use ? ", in use" : "");
- } else {
- DBG_NO_LOC(" %s [suspended]", path);
- }
- pthread_mutex_unlock(&handle->lock);
-}
-
-/* Tracker lock must be held by the caller. */
-static int fs_handle_tracked_suspend(struct fs_handle_tracked *handle)
-{
- int ret = 0;
- struct stat fs_stat;
- const char *path;
- const struct lttng_directory_handle *node_directory_handle;
-
- pthread_mutex_lock(&handle->lock);
- lttng_inode_borrow_location(
- handle->inode, &node_directory_handle, &path);
- LTTNG_ASSERT(handle->fd >= 0);
- if (handle->in_use) {
- /* This handle can't be suspended as it is currently in use. */
- ret = -EAGAIN;
- goto end;
- }
-
- ret = lttng_directory_handle_stat(
- node_directory_handle, path, &fs_stat);
- if (ret) {
- PERROR("Filesystem handle to %s cannot be suspended as stat() failed",
- path);
- ret = -errno;
- goto end;
- }
-
- if (fs_stat.st_ino != handle->ino) {
- /* Don't suspend as the handle would not be restorable. */
- WARN("Filesystem handle to %s cannot be suspended as its inode changed",
- path);
- ret = -ENOENT;
- goto end;
- }
-
- handle->offset = lseek(handle->fd, 0, SEEK_CUR);
- if (handle->offset == -1) {
- WARN("Filesystem handle to %s cannot be suspended as lseek() failed to sample its current position",
- path);
- ret = -errno;
- goto end;
- }
-
- ret = close(handle->fd);
- if (ret) {
- PERROR("Filesystem handle to %s cannot be suspended as close() failed",
- path);
- ret = -errno;
- goto end;
- }
- DBG("Suspended filesystem handle to %s (fd %i) at position %" PRId64,
- path, handle->fd, handle->offset);
- handle->fd = -1;
-end:
- if (ret) {
- handle->tracker->stats.errors++;
- }
- pthread_mutex_unlock(&handle->lock);
- return ret;
-}
-
-/* Caller must hold the tracker and handle's locks. */
-static int fs_handle_tracked_restore(struct fs_handle_tracked *handle)
-{
- int ret, fd = -1;
- const char *path;
- const struct lttng_directory_handle *node_directory_handle;
-
- lttng_inode_borrow_location(
- handle->inode, &node_directory_handle, &path);
-
- LTTNG_ASSERT(handle->fd == -1);
- LTTNG_ASSERT(path);
- ret = open_from_properties(
- node_directory_handle, path, &handle->properties);
- if (ret < 0) {
- PERROR("Failed to restore filesystem handle to %s, open() failed",
- path);
- ret = -errno;
- goto end;
- }
- fd = ret;
-
- ret = lseek(fd, handle->offset, SEEK_SET);
- if (ret < 0) {
- PERROR("Failed to restore filesystem handle to %s, lseek() failed",
- path);
- ret = -errno;
- goto end;
- }
- DBG("Restored filesystem handle to %s (fd %i) at position %" PRId64,
- path, fd, handle->offset);
- ret = 0;
- handle->fd = fd;
- fd = -1;
-end:
- if (fd >= 0) {
- (void) close(fd);
- }
- return ret;
-}
-
-static int open_from_properties(const struct lttng_directory_handle *dir_handle,
- const char *path, struct open_properties *properties)
-{
- int ret;
-
- /*
- * open() ignores the 'flags' parameter unless the O_CREAT or O_TMPFILE
- * flags are set. O_TMPFILE would not make sense in the context of a
- * suspendable fs_handle as it would not be restorable (see OPEN(2)),
- * thus it is ignored here.
- */
- if ((properties->flags & O_CREAT) && properties->mode.is_set) {
- ret = lttng_directory_handle_open_file(dir_handle, path,
- properties->flags, properties->mode.value);
- } else {
- ret = lttng_directory_handle_open_file(dir_handle, path,
- properties->flags, 0);
- }
- /*
- * Some flags should not be used beyond the initial open() of a
- * restorable file system handle. O_CREAT and O_TRUNC must
- * be cleared since it would be unexpected to re-use them
- * when the handle is retored:
- * - O_CREAT should not be needed as the file has been created
- * on the initial call to open(),
- * - O_TRUNC would destroy the file's contents by truncating it
- * to length 0.
- */
- properties->flags &= ~(O_CREAT | O_TRUNC);
- if (ret < 0) {
- ret = -errno;
- goto end;
- }
-end:
- return ret;
-}
-
-struct fd_tracker *fd_tracker_create(const char *unlinked_file_path,
- unsigned int capacity)
-{
- struct fd_tracker *tracker = zmalloc(sizeof(struct fd_tracker));
-
- if (!tracker) {
- goto end;
- }
-
- pthread_mutex_lock(&seed.lock);
- if (!seed.initialized) {
- seed.value = (unsigned long) time(NULL);
- seed.initialized = true;
- }
- pthread_mutex_unlock(&seed.lock);
-
- CDS_INIT_LIST_HEAD(&tracker->active_handles);
- CDS_INIT_LIST_HEAD(&tracker->suspended_handles);
- tracker->capacity = capacity;
- tracker->unsuspendable_fds = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0,
- CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
- if (!tracker->unsuspendable_fds) {
- ERR("Failed to create fd-tracker's unsuspendable_fds hash table");
- goto error;
- }
- tracker->inode_registry = lttng_inode_registry_create();
- if (!tracker->inode_registry) {
- ERR("Failed to create fd-tracker's inode registry");
- goto error;
- }
-
- tracker->unlinked_file_pool =
- lttng_unlinked_file_pool_create(unlinked_file_path);
- if (!tracker->unlinked_file_pool) {
- goto error;
- }
- DBG("File descriptor tracker created with a limit of %u simultaneously-opened FDs",
- capacity);
-end:
- return tracker;
-error:
- fd_tracker_destroy(tracker);
- return NULL;
-}
-
-void fd_tracker_log(struct fd_tracker *tracker)
-{
- struct fs_handle_tracked *handle;
- struct unsuspendable_fd *unsuspendable_fd;
- struct cds_lfht_iter iter;
-
- pthread_mutex_lock(&tracker->lock);
- DBG_NO_LOC("File descriptor tracker");
- DBG_NO_LOC(" Stats:");
- DBG_NO_LOC(" uses: %" PRIu64, tracker->stats.uses);
- DBG_NO_LOC(" misses: %" PRIu64, tracker->stats.misses);
- DBG_NO_LOC(" errors: %" PRIu64, tracker->stats.errors);
- DBG_NO_LOC(" Tracked: %u", TRACKED_COUNT(tracker));
- DBG_NO_LOC(" active: %u", ACTIVE_COUNT(tracker));
- DBG_NO_LOC(" suspendable: %u", SUSPENDABLE_COUNT(tracker));
- DBG_NO_LOC(" unsuspendable: %u", UNSUSPENDABLE_COUNT(tracker));
- DBG_NO_LOC(" suspended: %u", SUSPENDED_COUNT(tracker));
- DBG_NO_LOC(" capacity: %u", tracker->capacity);
-
- DBG_NO_LOC(" Tracked suspendable file descriptors");
- cds_list_for_each_entry(
- handle, &tracker->active_handles, handles_list_node) {
- fs_handle_tracked_log(handle);
- }
- cds_list_for_each_entry(handle, &tracker->suspended_handles,
- handles_list_node) {
- fs_handle_tracked_log(handle);
- }
- if (!SUSPENDABLE_COUNT(tracker)) {
- DBG_NO_LOC(" None");
- }
-
- DBG_NO_LOC(" Tracked unsuspendable file descriptors");
- rcu_read_lock();
- cds_lfht_for_each_entry(tracker->unsuspendable_fds, &iter,
- unsuspendable_fd, tracker_node) {
- DBG_NO_LOC(" %s [active, fd %d]",
- unsuspendable_fd->name ?: "Unnamed",
- unsuspendable_fd->fd);
- }
- rcu_read_unlock();
- if (!UNSUSPENDABLE_COUNT(tracker)) {
- DBG_NO_LOC(" None");
- }
-
- pthread_mutex_unlock(&tracker->lock);
-}
-
-int fd_tracker_destroy(struct fd_tracker *tracker)
-{
- int ret = 0;
-
- if (!tracker) {
- goto end;
- }
- /*
- * Refuse to destroy the tracker as fs_handles may still old
- * weak references to the tracker.
- */
- pthread_mutex_lock(&tracker->lock);
- if (TRACKED_COUNT(tracker)) {
- ERR("A file descriptor leak has been detected: %u tracked file descriptors are still being tracked",
- TRACKED_COUNT(tracker));
- pthread_mutex_unlock(&tracker->lock);
- fd_tracker_log(tracker);
- ret = -1;
- goto end;
- }
- pthread_mutex_unlock(&tracker->lock);
-
- if (tracker->unsuspendable_fds) {
- ret = cds_lfht_destroy(tracker->unsuspendable_fds, NULL);
- LTTNG_ASSERT(!ret);
- }
-
- lttng_inode_registry_destroy(tracker->inode_registry);
- lttng_unlinked_file_pool_destroy(tracker->unlinked_file_pool);
- pthread_mutex_destroy(&tracker->lock);
- free(tracker);
-end:
- return ret;
-}
-
-struct fs_handle *fd_tracker_open_fs_handle(struct fd_tracker *tracker,
- struct lttng_directory_handle *directory,
- const char *path,
- int flags,
- mode_t *mode)
-{
- int ret;
- struct fs_handle_tracked *handle = NULL;
- struct stat fd_stat;
- struct open_properties properties = {
- .flags = flags,
- .mode.is_set = !!mode,
- .mode.value = mode ? *mode : 0,
- };
-
- pthread_mutex_lock(&tracker->lock);
- if (ACTIVE_COUNT(tracker) == tracker->capacity) {
- if (tracker->count.suspendable.active > 0) {
- ret = fd_tracker_suspend_handles(tracker, 1);
- if (ret) {
- goto end;
- }
- } else {
- /*
- * There are not enough active suspendable file
- * descriptors to open a new fd and still accommodate
- * the tracker's capacity.
- */
- WARN("Cannot open file system handle, too many unsuspendable file descriptors are opened (%u)",
- tracker->count.unsuspendable);
- goto end;
- }
- }
-
- handle = zmalloc(sizeof(*handle));
- if (!handle) {
- goto end;
- }
- handle->parent = (typeof(handle->parent)) {
- .get_fd = fs_handle_tracked_get_fd,
- .put_fd = fs_handle_tracked_put_fd,
- .unlink = fs_handle_tracked_unlink,
- .close = fs_handle_tracked_close,
- };
-
- handle->tracker = tracker;
-
- ret = pthread_mutex_init(&handle->lock, NULL);
- if (ret) {
- PERROR("Failed to initialize handle mutex while creating fs handle");
- goto error_mutex_init;
- }
-
- handle->fd = open_from_properties(directory, path, &properties);
- if (handle->fd < 0) {
- PERROR("Failed to open fs handle to %s, open() returned", path);
- goto error;
- }
-
- handle->properties = properties;
-
- handle->inode = lttng_inode_registry_get_inode(tracker->inode_registry,
- directory, path, handle->fd,
- tracker->unlinked_file_pool);
- if (!handle->inode) {
- ERR("Failed to get lttng_inode corresponding to file %s", path);
- goto error;
- }
-
- if (fstat(handle->fd, &fd_stat)) {
- PERROR("Failed to retrieve file descriptor inode while creating fs handle, fstat() returned");
- goto error;
- }
- handle->ino = fd_stat.st_ino;
-
- fd_tracker_track(tracker, handle);
-end:
- pthread_mutex_unlock(&tracker->lock);
- return handle ? &handle->parent : NULL;
-error:
- if (handle->inode) {
- lttng_inode_put(handle->inode);
- }
- pthread_mutex_destroy(&handle->lock);
-error_mutex_init:
- free(handle);
- handle = NULL;
- goto end;
-}
-
-/* Caller must hold the tracker's lock. */
-static int fd_tracker_suspend_handles(
- struct fd_tracker *tracker, unsigned int count)
-{
- unsigned int left_to_close = count;
- unsigned int attempts_left = tracker->count.suspendable.active;
- struct fs_handle_tracked *handle, *tmp;
-
- cds_list_for_each_entry_safe(handle, tmp, &tracker->active_handles,
- handles_list_node) {
- int ret;
-
- fd_tracker_untrack(tracker, handle);
- ret = fs_handle_tracked_suspend(handle);
- fd_tracker_track(tracker, handle);
- if (!ret) {
- left_to_close--;
- }
- attempts_left--;
-
- if (left_to_close == 0 || attempts_left == 0) {
- break;
- }
- }
- return left_to_close ? -EMFILE : 0;
-}
-
-int fd_tracker_open_unsuspendable_fd(struct fd_tracker *tracker,
- int *out_fds,
- const char **names,
- unsigned int fd_count,
- fd_open_cb open,
- void *user_data)
-{
- int ret, user_ret, i, fds_to_suspend;
- unsigned int active_fds;
- struct unsuspendable_fd **entries;
-
- entries = zmalloc(fd_count * sizeof(*entries));
- if (!entries) {
- ret = -1;
- goto end;
- }
-
- pthread_mutex_lock(&tracker->lock);
-
- active_fds = ACTIVE_COUNT(tracker);
- fds_to_suspend = (int) active_fds + (int) fd_count -
- (int) tracker->capacity;
- if (fds_to_suspend > 0) {
- if (fds_to_suspend <= tracker->count.suspendable.active) {
- ret = fd_tracker_suspend_handles(
- tracker, fds_to_suspend);
- if (ret) {
- goto end_unlock;
- }
- } else {
- /*
- * There are not enough active suspendable file
- * descriptors to open a new fd and still accommodates the
- * tracker's capacity.
- */
- WARN("Cannot open unsuspendable fd, too many unsuspendable file descriptors are opened (%u)",
- tracker->count.unsuspendable);
- ret = -EMFILE;
- goto end_unlock;
- }
- }
-
- user_ret = open(user_data, out_fds);
- if (user_ret) {
- ret = user_ret;
- goto end_unlock;
- }
-
- /*
- * Add the fds returned by the user's callback to the hashtable
- * of unsuspendable fds.
- */
- for (i = 0; i < fd_count; i++) {
- struct unsuspendable_fd *entry = unsuspendable_fd_create(
- names ? names[i] : NULL, out_fds[i]);
-
- if (!entry) {
- ret = -1;
- goto end_free_entries;
- }
- entries[i] = entry;
- }
-
- rcu_read_lock();
- for (i = 0; i < fd_count; i++) {
- struct cds_lfht_node *node;
- struct unsuspendable_fd *entry = entries[i];
-
- node = cds_lfht_add_unique(tracker->unsuspendable_fds,
- hash_key_ulong((void *) (unsigned long)
- out_fds[i],
- seed.value),
- match_fd, (void *) (unsigned long) out_fds[i],
- &entry->tracker_node);
-
- if (node != &entry->tracker_node) {
- ret = -EEXIST;
- rcu_read_unlock();
- goto end_free_entries;
- }
- entries[i] = NULL;
- }
- tracker->count.unsuspendable += fd_count;
- rcu_read_unlock();
- ret = user_ret;
-end_unlock:
- pthread_mutex_unlock(&tracker->lock);
-end:
- free(entries);
- return ret;
-end_free_entries:
- for (i = 0; i < fd_count; i++) {
- unsuspendable_fd_destroy(entries[i]);
- }
- goto end_unlock;
-}
-
-int fd_tracker_close_unsuspendable_fd(struct fd_tracker *tracker,
- int *fds_in,
- unsigned int fd_count,
- fd_close_cb close,
- void *user_data)
-{
- int i, ret, user_ret;
- int *fds = NULL;
-
- /*
- * Maintain a local copy of fds_in as the user's callback may modify its
- * contents (e.g. setting the fd(s) to -1 after close).
- */
- fds = malloc(sizeof(*fds) * fd_count);
- if (!fds) {
- ret = -1;
- goto end;
- }
- memcpy(fds, fds_in, sizeof(*fds) * fd_count);
-
- pthread_mutex_lock(&tracker->lock);
- rcu_read_lock();
-
- /* Let the user close the file descriptors. */
- user_ret = close(user_data, fds_in);
- if (user_ret) {
- ret = user_ret;
- goto end_unlock;
- }
-
- /* Untrack the fds that were just closed by the user's callback. */
- for (i = 0; i < fd_count; i++) {
- struct cds_lfht_node *node;
- struct cds_lfht_iter iter;
- struct unsuspendable_fd *entry;
-
- cds_lfht_lookup(tracker->unsuspendable_fds,
- hash_key_ulong((void *) (unsigned long) fds[i],
- seed.value),
- match_fd, (void *) (unsigned long) fds[i],
- &iter);
- node = cds_lfht_iter_get_node(&iter);
- if (!node) {
- /* Unknown file descriptor. */
- WARN("Untracked file descriptor %d passed to fd_tracker_close_unsuspendable_fd()",
- fds[i]);
- ret = -EINVAL;
- goto end_unlock;
- }
- entry = caa_container_of(
- node, struct unsuspendable_fd, tracker_node);
-
- cds_lfht_del(tracker->unsuspendable_fds, node);
- unsuspendable_fd_destroy(entry);
- fds[i] = -1;
- }
-
- tracker->count.unsuspendable -= fd_count;
- ret = 0;
-end_unlock:
- rcu_read_unlock();
- pthread_mutex_unlock(&tracker->lock);
- free(fds);
-end:
- return ret;
-}
-
-/* Caller must have taken the tracker's and handle's locks. */
-static void fd_tracker_track(
- struct fd_tracker *tracker, struct fs_handle_tracked *handle)
-{
- if (handle->fd >= 0) {
- tracker->count.suspendable.active++;
- cds_list_add_tail(&handle->handles_list_node,
- &tracker->active_handles);
- } else {
- tracker->count.suspendable.suspended++;
- cds_list_add_tail(&handle->handles_list_node,
- &tracker->suspended_handles);
- }
-}
-
-/* Caller must have taken the tracker's and handle's locks. */
-static void fd_tracker_untrack(
- struct fd_tracker *tracker, struct fs_handle_tracked *handle)
-{
- if (handle->fd >= 0) {
- tracker->count.suspendable.active--;
- } else {
- tracker->count.suspendable.suspended--;
- }
- cds_list_del(&handle->handles_list_node);
-}
-
-/* Caller must have taken the tracker's and handle's locks. */
-static int fd_tracker_restore_handle(
- struct fd_tracker *tracker, struct fs_handle_tracked *handle)
-{
- int ret;
-
- fd_tracker_untrack(tracker, handle);
- if (ACTIVE_COUNT(tracker) >= tracker->capacity) {
- ret = fd_tracker_suspend_handles(tracker, 1);
- if (ret) {
- goto end;
- }
- }
- ret = fs_handle_tracked_restore(handle);
-end:
- fd_tracker_track(tracker, handle);
- return ret ? ret : handle->fd;
-}
-
-static int fs_handle_tracked_get_fd(struct fs_handle *_handle)
-{
- int ret;
- struct fs_handle_tracked *handle =
- container_of(_handle, struct fs_handle_tracked, parent);
-
- /*
- * TODO This should be optimized as it is a fairly hot path.
- * The fd-tracker's lock should only be taken when a fs_handle is
- * restored (slow path). On the fast path (fs_handle is active),
- * the only effect on the fd_tracker is marking the handle as the
- * most recently used. Currently, it is done by a call to the
- * track/untrack helpers, but it should be done atomically.
- *
- * Note that the lock's nesting order must still be respected here.
- * The handle's lock nests inside the tracker's lock.
- */
- pthread_mutex_lock(&handle->tracker->lock);
- pthread_mutex_lock(&handle->lock);
- LTTNG_ASSERT(!handle->in_use);
-
- handle->tracker->stats.uses++;
- if (handle->fd >= 0) {
- ret = handle->fd;
- /* Mark as most recently used. */
- fd_tracker_untrack(handle->tracker, handle);
- fd_tracker_track(handle->tracker, handle);
- } else {
- handle->tracker->stats.misses++;
- ret = fd_tracker_restore_handle(handle->tracker, handle);
- if (ret < 0) {
- handle->tracker->stats.errors++;
- goto end;
- }
- }
- handle->in_use = true;
-end:
- pthread_mutex_unlock(&handle->lock);
- pthread_mutex_unlock(&handle->tracker->lock);
- return ret;
-}
-
-static void fs_handle_tracked_put_fd(struct fs_handle *_handle)
-{
- struct fs_handle_tracked *handle =
- container_of(_handle, struct fs_handle_tracked, parent);
-
- pthread_mutex_lock(&handle->lock);
- handle->in_use = false;
- pthread_mutex_unlock(&handle->lock);
-}
-
-static int fs_handle_tracked_unlink(struct fs_handle *_handle)
-{
- int ret;
- struct fs_handle_tracked *handle =
- container_of(_handle, struct fs_handle_tracked, parent);
-
- pthread_mutex_lock(&handle->tracker->lock);
- pthread_mutex_lock(&handle->lock);
- ret = lttng_inode_unlink(handle->inode);
- pthread_mutex_unlock(&handle->lock);
- pthread_mutex_unlock(&handle->tracker->lock);
- return ret;
-}
-
-static int fs_handle_tracked_close(struct fs_handle *_handle)
-{
- int ret = 0;
- const char *path = NULL;
- struct fs_handle_tracked *handle =
- container_of(_handle, struct fs_handle_tracked, parent);
- struct lttng_directory_handle *inode_directory_handle = NULL;
-
- if (!handle) {
- ret = -EINVAL;
- goto end;
- }
-
- pthread_mutex_lock(&handle->tracker->lock);
- pthread_mutex_lock(&handle->lock);
- if (handle->inode) {
- lttng_inode_borrow_location(handle->inode, NULL, &path);
- /*
- * Here a reference to the inode's directory handle is acquired
- * to prevent the last reference to it from being released while
- * the tracker's lock is taken.
- *
- * If this wasn't done, the directory handle could attempt to
- * close its underlying directory file descriptor, which would
- * attempt to lock the tracker's lock, resulting in a deadlock.
- *
- * Since a new reference to the directory handle is taken within
- * the scope of this function, it is not possible for the last
- * reference to the inode's location directory handle to be
- * released during the call to lttng_inode_put().
- *
- * We wait until the tracker's lock is released to release the
- * reference. Hence, the call to the tracker is delayed just
- * enough to not attempt to recursively acquire the tracker's
- * lock twice.
- */
- inode_directory_handle =
- lttng_inode_get_location_directory_handle(
- handle->inode);
- }
- fd_tracker_untrack(handle->tracker, handle);
- if (handle->fd >= 0) {
- /*
- * The return value of close() is not propagated as there
- * isn't much the user can do about it.
- */
- if (close(handle->fd)) {
- PERROR("Failed to close the file descriptor (%d) of fs handle to %s, close() returned",
- handle->fd, path ? path : "Unknown");
- }
- handle->fd = -1;
- }
- if (handle->inode) {
- lttng_inode_put(handle->inode);
- }
- pthread_mutex_unlock(&handle->lock);
- pthread_mutex_destroy(&handle->lock);
- pthread_mutex_unlock(&handle->tracker->lock);
- free(handle);
- lttng_directory_handle_put(inode_directory_handle);
-end:
- return ret;
-}
--- /dev/null
+/*
+ * Copyright (C) 2018-2020 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#include <urcu.h>
+#include <urcu/list.h>
+#include <urcu/rculfhash.h>
+
+#include <fcntl.h>
+#include <inttypes.h>
+#include <pthread.h>
+#include <stdbool.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#include <common/defaults.h>
+#include <common/error.h>
+#include <common/fs-handle-internal.h>
+#include <common/hashtable/hashtable.h>
+#include <common/hashtable/utils.h>
+#include <common/macros.h>
+#include <common/optional.h>
+
+#include "fd-tracker.h"
+#include "inode.h"
+
+/* Tracker lock must be taken by the user. */
+#define TRACKED_COUNT(tracker) \
+ (tracker->count.suspendable.active + \
+ tracker->count.suspendable.suspended + \
+ tracker->count.unsuspendable)
+
+/* Tracker lock must be taken by the user. */
+#define ACTIVE_COUNT(tracker) \
+ (tracker->count.suspendable.active + tracker->count.unsuspendable)
+
+/* Tracker lock must be taken by the user. */
+#define SUSPENDED_COUNT(tracker) (tracker->count.suspendable.suspended)
+
+/* Tracker lock must be taken by the user. */
+#define SUSPENDABLE_COUNT(tracker) \
+ (tracker->count.suspendable.active + \
+ tracker->count.suspendable.suspended)
+
+/* Tracker lock must be taken by the user. */
+#define UNSUSPENDABLE_COUNT(tracker) (tracker->count.unsuspendable)
+
+struct fd_tracker {
+ pthread_mutex_t lock;
+ struct {
+ struct {
+ unsigned int active;
+ unsigned int suspended;
+ } suspendable;
+ unsigned int unsuspendable;
+ } count;
+ unsigned int capacity;
+ struct {
+ uint64_t uses;
+ uint64_t misses;
+ /* Failures to suspend or restore fs handles. */
+ uint64_t errors;
+ } stats;
+ /*
+ * The head of the active_handles list is always the least recently
+ * used active handle. When an handle is used, it is removed from the
+ * list and added to the end. When a file has to be suspended, the
+ * first element in the list is "popped", suspended, and added to the
+ * list of suspended handles.
+ */
+ struct cds_list_head active_handles;
+ struct cds_list_head suspended_handles;
+ struct cds_lfht *unsuspendable_fds;
+ struct lttng_inode_registry *inode_registry;
+ /* Unlinked files are moved in this directory under a unique name. */
+ struct lttng_directory_handle *unlink_directory_handle;
+ struct lttng_unlinked_file_pool *unlinked_file_pool;
+};
+
+struct open_properties {
+ int flags;
+ LTTNG_OPTIONAL(mode_t) mode;
+};
+
+/*
+ * A fs_handle_tracked is not ref-counted. Therefore, it is assumed that a
+ * handle is never in-use while it is being reclaimed. It can be
+ * shared by multiple threads, but external synchronization is required
+ * to ensure it is not still being used when it is reclaimed (close method).
+ * In this respect, it is not different from a regular file descriptor.
+ *
+ * The fs_handle lock always nests _within_ the tracker's lock.
+ */
+struct fs_handle_tracked {
+ struct fs_handle parent;
+ pthread_mutex_t lock;
+ /*
+ * Weak reference to the tracker. All fs_handles are assumed to have
+ * been closed at the moment of the destruction of the fd_tracker.
+ */
+ struct fd_tracker *tracker;
+ struct open_properties properties;
+ struct lttng_inode *inode;
+ int fd;
+ /* inode number of the file at the time of the handle's creation. */
+ uint64_t ino;
+ bool in_use;
+ /* Offset to which the file should be restored. */
+ off_t offset;
+ struct cds_list_head handles_list_node;
+};
+
+struct unsuspendable_fd {
+ /*
+ * Accesses are only performed through the tracker, which is protected
+ * by its own lock.
+ */
+ int fd;
+ char *name;
+ struct cds_lfht_node tracker_node;
+ struct rcu_head rcu_head;
+};
+
+static struct {
+ pthread_mutex_t lock;
+ bool initialized;
+ unsigned long value;
+} seed = {
+ .lock = PTHREAD_MUTEX_INITIALIZER,
+};
+
+static int match_fd(struct cds_lfht_node *node, const void *key);
+static void unsuspendable_fd_destroy(struct unsuspendable_fd *entry);
+static struct unsuspendable_fd *unsuspendable_fd_create(
+ const char *name, int fd);
+static int open_from_properties(const struct lttng_directory_handle *dir_handle,
+ const char *path, struct open_properties *properties);
+
+static void fs_handle_tracked_log(struct fs_handle_tracked *handle);
+static int fs_handle_tracked_suspend(struct fs_handle_tracked *handle);
+static int fs_handle_tracked_restore(struct fs_handle_tracked *handle);
+static int fs_handle_tracked_get_fd(struct fs_handle *_handle);
+static void fs_handle_tracked_put_fd(struct fs_handle *_handle);
+static int fs_handle_tracked_unlink(struct fs_handle *_handle);
+static int fs_handle_tracked_close(struct fs_handle *_handle);
+
+static void fd_tracker_track(
+ struct fd_tracker *tracker, struct fs_handle_tracked *handle);
+static void fd_tracker_untrack(
+ struct fd_tracker *tracker, struct fs_handle_tracked *handle);
+static int fd_tracker_suspend_handles(
+ struct fd_tracker *tracker, unsigned int count);
+static int fd_tracker_restore_handle(
+ struct fd_tracker *tracker, struct fs_handle_tracked *handle);
+
+/* Match function of the tracker's unsuspendable_fds hash table. */
+static int match_fd(struct cds_lfht_node *node, const void *key)
+{
+ struct unsuspendable_fd *entry = caa_container_of(
+ node, struct unsuspendable_fd, tracker_node);
+
+ return hash_match_key_ulong(
+ (void *) (unsigned long) entry->fd, (void *) key);
+}
+
+static void delete_unsuspendable_fd(struct rcu_head *head)
+{
+ struct unsuspendable_fd *fd = caa_container_of(
+ head, struct unsuspendable_fd, rcu_head);
+
+ free(fd->name);
+ free(fd);
+}
+
+static void unsuspendable_fd_destroy(struct unsuspendable_fd *entry)
+{
+ if (!entry) {
+ return;
+ }
+ call_rcu(&entry->rcu_head, delete_unsuspendable_fd);
+}
+
+static struct unsuspendable_fd *unsuspendable_fd_create(
+ const char *name, int fd)
+{
+ struct unsuspendable_fd *entry = (unsuspendable_fd *) zmalloc(sizeof(*entry));
+
+ if (!entry) {
+ goto error;
+ }
+ if (name) {
+ entry->name = strdup(name);
+ if (!entry->name) {
+ goto error;
+ }
+ }
+ cds_lfht_node_init(&entry->tracker_node);
+ entry->fd = fd;
+ return entry;
+error:
+ unsuspendable_fd_destroy(entry);
+ return NULL;
+}
+
+static void fs_handle_tracked_log(struct fs_handle_tracked *handle)
+{
+ const char *path;
+
+ pthread_mutex_lock(&handle->lock);
+ lttng_inode_borrow_location(handle->inode, NULL, &path);
+
+ if (handle->fd >= 0) {
+ DBG_NO_LOC(" %s [active, fd %d%s]", path, handle->fd,
+ handle->in_use ? ", in use" : "");
+ } else {
+ DBG_NO_LOC(" %s [suspended]", path);
+ }
+ pthread_mutex_unlock(&handle->lock);
+}
+
+/* Tracker lock must be held by the caller. */
+static int fs_handle_tracked_suspend(struct fs_handle_tracked *handle)
+{
+ int ret = 0;
+ struct stat fs_stat;
+ const char *path;
+ const struct lttng_directory_handle *node_directory_handle;
+
+ pthread_mutex_lock(&handle->lock);
+ lttng_inode_borrow_location(
+ handle->inode, &node_directory_handle, &path);
+ LTTNG_ASSERT(handle->fd >= 0);
+ if (handle->in_use) {
+ /* This handle can't be suspended as it is currently in use. */
+ ret = -EAGAIN;
+ goto end;
+ }
+
+ ret = lttng_directory_handle_stat(
+ node_directory_handle, path, &fs_stat);
+ if (ret) {
+ PERROR("Filesystem handle to %s cannot be suspended as stat() failed",
+ path);
+ ret = -errno;
+ goto end;
+ }
+
+ if (fs_stat.st_ino != handle->ino) {
+ /* Don't suspend as the handle would not be restorable. */
+ WARN("Filesystem handle to %s cannot be suspended as its inode changed",
+ path);
+ ret = -ENOENT;
+ goto end;
+ }
+
+ handle->offset = lseek(handle->fd, 0, SEEK_CUR);
+ if (handle->offset == -1) {
+ WARN("Filesystem handle to %s cannot be suspended as lseek() failed to sample its current position",
+ path);
+ ret = -errno;
+ goto end;
+ }
+
+ ret = close(handle->fd);
+ if (ret) {
+ PERROR("Filesystem handle to %s cannot be suspended as close() failed",
+ path);
+ ret = -errno;
+ goto end;
+ }
+ DBG("Suspended filesystem handle to %s (fd %i) at position %" PRId64,
+ path, handle->fd, handle->offset);
+ handle->fd = -1;
+end:
+ if (ret) {
+ handle->tracker->stats.errors++;
+ }
+ pthread_mutex_unlock(&handle->lock);
+ return ret;
+}
+
+/* Caller must hold the tracker and handle's locks. */
+static int fs_handle_tracked_restore(struct fs_handle_tracked *handle)
+{
+ int ret, fd = -1;
+ const char *path;
+ const struct lttng_directory_handle *node_directory_handle;
+
+ lttng_inode_borrow_location(
+ handle->inode, &node_directory_handle, &path);
+
+ LTTNG_ASSERT(handle->fd == -1);
+ LTTNG_ASSERT(path);
+ ret = open_from_properties(
+ node_directory_handle, path, &handle->properties);
+ if (ret < 0) {
+ PERROR("Failed to restore filesystem handle to %s, open() failed",
+ path);
+ ret = -errno;
+ goto end;
+ }
+ fd = ret;
+
+ ret = lseek(fd, handle->offset, SEEK_SET);
+ if (ret < 0) {
+ PERROR("Failed to restore filesystem handle to %s, lseek() failed",
+ path);
+ ret = -errno;
+ goto end;
+ }
+ DBG("Restored filesystem handle to %s (fd %i) at position %" PRId64,
+ path, fd, handle->offset);
+ ret = 0;
+ handle->fd = fd;
+ fd = -1;
+end:
+ if (fd >= 0) {
+ (void) close(fd);
+ }
+ return ret;
+}
+
+static int open_from_properties(const struct lttng_directory_handle *dir_handle,
+ const char *path, struct open_properties *properties)
+{
+ int ret;
+
+ /*
+ * open() ignores the 'flags' parameter unless the O_CREAT or O_TMPFILE
+ * flags are set. O_TMPFILE would not make sense in the context of a
+ * suspendable fs_handle as it would not be restorable (see OPEN(2)),
+ * thus it is ignored here.
+ */
+ if ((properties->flags & O_CREAT) && properties->mode.is_set) {
+ ret = lttng_directory_handle_open_file(dir_handle, path,
+ properties->flags, properties->mode.value);
+ } else {
+ ret = lttng_directory_handle_open_file(dir_handle, path,
+ properties->flags, 0);
+ }
+ /*
+ * Some flags should not be used beyond the initial open() of a
+ * restorable file system handle. O_CREAT and O_TRUNC must
+ * be cleared since it would be unexpected to re-use them
+ * when the handle is retored:
+ * - O_CREAT should not be needed as the file has been created
+ * on the initial call to open(),
+ * - O_TRUNC would destroy the file's contents by truncating it
+ * to length 0.
+ */
+ properties->flags &= ~(O_CREAT | O_TRUNC);
+ if (ret < 0) {
+ ret = -errno;
+ goto end;
+ }
+end:
+ return ret;
+}
+
+struct fd_tracker *fd_tracker_create(const char *unlinked_file_path,
+ unsigned int capacity)
+{
+ struct fd_tracker *tracker = (fd_tracker *) zmalloc(sizeof(struct fd_tracker));
+
+ if (!tracker) {
+ goto end;
+ }
+
+ pthread_mutex_lock(&seed.lock);
+ if (!seed.initialized) {
+ seed.value = (unsigned long) time(NULL);
+ seed.initialized = true;
+ }
+ pthread_mutex_unlock(&seed.lock);
+
+ CDS_INIT_LIST_HEAD(&tracker->active_handles);
+ CDS_INIT_LIST_HEAD(&tracker->suspended_handles);
+ tracker->capacity = capacity;
+ tracker->unsuspendable_fds = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0,
+ CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
+ if (!tracker->unsuspendable_fds) {
+ ERR("Failed to create fd-tracker's unsuspendable_fds hash table");
+ goto error;
+ }
+ tracker->inode_registry = lttng_inode_registry_create();
+ if (!tracker->inode_registry) {
+ ERR("Failed to create fd-tracker's inode registry");
+ goto error;
+ }
+
+ tracker->unlinked_file_pool =
+ lttng_unlinked_file_pool_create(unlinked_file_path);
+ if (!tracker->unlinked_file_pool) {
+ goto error;
+ }
+ DBG("File descriptor tracker created with a limit of %u simultaneously-opened FDs",
+ capacity);
+end:
+ return tracker;
+error:
+ fd_tracker_destroy(tracker);
+ return NULL;
+}
+
+void fd_tracker_log(struct fd_tracker *tracker)
+{
+ struct fs_handle_tracked *handle;
+ struct unsuspendable_fd *unsuspendable_fd;
+ struct cds_lfht_iter iter;
+
+ pthread_mutex_lock(&tracker->lock);
+ DBG_NO_LOC("File descriptor tracker");
+ DBG_NO_LOC(" Stats:");
+ DBG_NO_LOC(" uses: %" PRIu64, tracker->stats.uses);
+ DBG_NO_LOC(" misses: %" PRIu64, tracker->stats.misses);
+ DBG_NO_LOC(" errors: %" PRIu64, tracker->stats.errors);
+ DBG_NO_LOC(" Tracked: %u", TRACKED_COUNT(tracker));
+ DBG_NO_LOC(" active: %u", ACTIVE_COUNT(tracker));
+ DBG_NO_LOC(" suspendable: %u", SUSPENDABLE_COUNT(tracker));
+ DBG_NO_LOC(" unsuspendable: %u", UNSUSPENDABLE_COUNT(tracker));
+ DBG_NO_LOC(" suspended: %u", SUSPENDED_COUNT(tracker));
+ DBG_NO_LOC(" capacity: %u", tracker->capacity);
+
+ DBG_NO_LOC(" Tracked suspendable file descriptors");
+ cds_list_for_each_entry(
+ handle, &tracker->active_handles, handles_list_node) {
+ fs_handle_tracked_log(handle);
+ }
+ cds_list_for_each_entry(handle, &tracker->suspended_handles,
+ handles_list_node) {
+ fs_handle_tracked_log(handle);
+ }
+ if (!SUSPENDABLE_COUNT(tracker)) {
+ DBG_NO_LOC(" None");
+ }
+
+ DBG_NO_LOC(" Tracked unsuspendable file descriptors");
+ rcu_read_lock();
+ cds_lfht_for_each_entry(tracker->unsuspendable_fds, &iter,
+ unsuspendable_fd, tracker_node) {
+ DBG_NO_LOC(" %s [active, fd %d]",
+ unsuspendable_fd->name ?: "Unnamed",
+ unsuspendable_fd->fd);
+ }
+ rcu_read_unlock();
+ if (!UNSUSPENDABLE_COUNT(tracker)) {
+ DBG_NO_LOC(" None");
+ }
+
+ pthread_mutex_unlock(&tracker->lock);
+}
+
+int fd_tracker_destroy(struct fd_tracker *tracker)
+{
+ int ret = 0;
+
+ if (!tracker) {
+ goto end;
+ }
+ /*
+ * Refuse to destroy the tracker as fs_handles may still old
+ * weak references to the tracker.
+ */
+ pthread_mutex_lock(&tracker->lock);
+ if (TRACKED_COUNT(tracker)) {
+ ERR("A file descriptor leak has been detected: %u tracked file descriptors are still being tracked",
+ TRACKED_COUNT(tracker));
+ pthread_mutex_unlock(&tracker->lock);
+ fd_tracker_log(tracker);
+ ret = -1;
+ goto end;
+ }
+ pthread_mutex_unlock(&tracker->lock);
+
+ if (tracker->unsuspendable_fds) {
+ ret = cds_lfht_destroy(tracker->unsuspendable_fds, NULL);
+ LTTNG_ASSERT(!ret);
+ }
+
+ lttng_inode_registry_destroy(tracker->inode_registry);
+ lttng_unlinked_file_pool_destroy(tracker->unlinked_file_pool);
+ pthread_mutex_destroy(&tracker->lock);
+ free(tracker);
+end:
+ return ret;
+}
+
+struct fs_handle *fd_tracker_open_fs_handle(struct fd_tracker *tracker,
+ struct lttng_directory_handle *directory,
+ const char *path,
+ int flags,
+ mode_t *mode)
+{
+ int ret;
+ struct fs_handle_tracked *handle = NULL;
+ struct stat fd_stat;
+ struct open_properties properties = {
+ .flags = flags,
+ .mode = {
+ .is_set = !!mode,
+ .value = mode ? *mode : 0,
+ }
+ };
+
+ pthread_mutex_lock(&tracker->lock);
+ if (ACTIVE_COUNT(tracker) == tracker->capacity) {
+ if (tracker->count.suspendable.active > 0) {
+ ret = fd_tracker_suspend_handles(tracker, 1);
+ if (ret) {
+ goto end;
+ }
+ } else {
+ /*
+ * There are not enough active suspendable file
+ * descriptors to open a new fd and still accommodate
+ * the tracker's capacity.
+ */
+ WARN("Cannot open file system handle, too many unsuspendable file descriptors are opened (%u)",
+ tracker->count.unsuspendable);
+ goto end;
+ }
+ }
+
+ handle = (fs_handle_tracked *) zmalloc(sizeof(*handle));
+ if (!handle) {
+ goto end;
+ }
+ handle->parent = (typeof(handle->parent)) {
+ .get_fd = fs_handle_tracked_get_fd,
+ .put_fd = fs_handle_tracked_put_fd,
+ .unlink = fs_handle_tracked_unlink,
+ .close = fs_handle_tracked_close,
+ };
+
+ handle->tracker = tracker;
+
+ ret = pthread_mutex_init(&handle->lock, NULL);
+ if (ret) {
+ PERROR("Failed to initialize handle mutex while creating fs handle");
+ goto error_mutex_init;
+ }
+
+ handle->fd = open_from_properties(directory, path, &properties);
+ if (handle->fd < 0) {
+ PERROR("Failed to open fs handle to %s, open() returned", path);
+ goto error;
+ }
+
+ handle->properties = properties;
+
+ handle->inode = lttng_inode_registry_get_inode(tracker->inode_registry,
+ directory, path, handle->fd,
+ tracker->unlinked_file_pool);
+ if (!handle->inode) {
+ ERR("Failed to get lttng_inode corresponding to file %s", path);
+ goto error;
+ }
+
+ if (fstat(handle->fd, &fd_stat)) {
+ PERROR("Failed to retrieve file descriptor inode while creating fs handle, fstat() returned");
+ goto error;
+ }
+ handle->ino = fd_stat.st_ino;
+
+ fd_tracker_track(tracker, handle);
+end:
+ pthread_mutex_unlock(&tracker->lock);
+ return handle ? &handle->parent : NULL;
+error:
+ if (handle->inode) {
+ lttng_inode_put(handle->inode);
+ }
+ pthread_mutex_destroy(&handle->lock);
+error_mutex_init:
+ free(handle);
+ handle = NULL;
+ goto end;
+}
+
+/* Caller must hold the tracker's lock. */
+static int fd_tracker_suspend_handles(
+ struct fd_tracker *tracker, unsigned int count)
+{
+ unsigned int left_to_close = count;
+ unsigned int attempts_left = tracker->count.suspendable.active;
+ struct fs_handle_tracked *handle, *tmp;
+
+ cds_list_for_each_entry_safe(handle, tmp, &tracker->active_handles,
+ handles_list_node) {
+ int ret;
+
+ fd_tracker_untrack(tracker, handle);
+ ret = fs_handle_tracked_suspend(handle);
+ fd_tracker_track(tracker, handle);
+ if (!ret) {
+ left_to_close--;
+ }
+ attempts_left--;
+
+ if (left_to_close == 0 || attempts_left == 0) {
+ break;
+ }
+ }
+ return left_to_close ? -EMFILE : 0;
+}
+
+int fd_tracker_open_unsuspendable_fd(struct fd_tracker *tracker,
+ int *out_fds,
+ const char **names,
+ unsigned int fd_count,
+ fd_open_cb open,
+ void *user_data)
+{
+ int ret, user_ret, i, fds_to_suspend;
+ unsigned int active_fds;
+ struct unsuspendable_fd **entries;
+
+ entries = (unsuspendable_fd **) zmalloc(fd_count * sizeof(*entries));
+ if (!entries) {
+ ret = -1;
+ goto end;
+ }
+
+ pthread_mutex_lock(&tracker->lock);
+
+ active_fds = ACTIVE_COUNT(tracker);
+ fds_to_suspend = (int) active_fds + (int) fd_count -
+ (int) tracker->capacity;
+ if (fds_to_suspend > 0) {
+ if (fds_to_suspend <= tracker->count.suspendable.active) {
+ ret = fd_tracker_suspend_handles(
+ tracker, fds_to_suspend);
+ if (ret) {
+ goto end_unlock;
+ }
+ } else {
+ /*
+ * There are not enough active suspendable file
+ * descriptors to open a new fd and still accommodates the
+ * tracker's capacity.
+ */
+ WARN("Cannot open unsuspendable fd, too many unsuspendable file descriptors are opened (%u)",
+ tracker->count.unsuspendable);
+ ret = -EMFILE;
+ goto end_unlock;
+ }
+ }
+
+ user_ret = open(user_data, out_fds);
+ if (user_ret) {
+ ret = user_ret;
+ goto end_unlock;
+ }
+
+ /*
+ * Add the fds returned by the user's callback to the hashtable
+ * of unsuspendable fds.
+ */
+ for (i = 0; i < fd_count; i++) {
+ struct unsuspendable_fd *entry = unsuspendable_fd_create(
+ names ? names[i] : NULL, out_fds[i]);
+
+ if (!entry) {
+ ret = -1;
+ goto end_free_entries;
+ }
+ entries[i] = entry;
+ }
+
+ rcu_read_lock();
+ for (i = 0; i < fd_count; i++) {
+ struct cds_lfht_node *node;
+ struct unsuspendable_fd *entry = entries[i];
+
+ node = cds_lfht_add_unique(tracker->unsuspendable_fds,
+ hash_key_ulong((void *) (unsigned long)
+ out_fds[i],
+ seed.value),
+ match_fd, (void *) (unsigned long) out_fds[i],
+ &entry->tracker_node);
+
+ if (node != &entry->tracker_node) {
+ ret = -EEXIST;
+ rcu_read_unlock();
+ goto end_free_entries;
+ }
+ entries[i] = NULL;
+ }
+ tracker->count.unsuspendable += fd_count;
+ rcu_read_unlock();
+ ret = user_ret;
+end_unlock:
+ pthread_mutex_unlock(&tracker->lock);
+end:
+ free(entries);
+ return ret;
+end_free_entries:
+ for (i = 0; i < fd_count; i++) {
+ unsuspendable_fd_destroy(entries[i]);
+ }
+ goto end_unlock;
+}
+
+int fd_tracker_close_unsuspendable_fd(struct fd_tracker *tracker,
+ int *fds_in,
+ unsigned int fd_count,
+ fd_close_cb close,
+ void *user_data)
+{
+ int i, ret, user_ret;
+ int *fds = NULL;
+
+ /*
+ * Maintain a local copy of fds_in as the user's callback may modify its
+ * contents (e.g. setting the fd(s) to -1 after close).
+ */
+ fds = (int *) malloc(sizeof(*fds) * fd_count);
+ if (!fds) {
+ ret = -1;
+ goto end;
+ }
+ memcpy(fds, fds_in, sizeof(*fds) * fd_count);
+
+ pthread_mutex_lock(&tracker->lock);
+ rcu_read_lock();
+
+ /* Let the user close the file descriptors. */
+ user_ret = close(user_data, fds_in);
+ if (user_ret) {
+ ret = user_ret;
+ goto end_unlock;
+ }
+
+ /* Untrack the fds that were just closed by the user's callback. */
+ for (i = 0; i < fd_count; i++) {
+ struct cds_lfht_node *node;
+ struct cds_lfht_iter iter;
+ struct unsuspendable_fd *entry;
+
+ cds_lfht_lookup(tracker->unsuspendable_fds,
+ hash_key_ulong((void *) (unsigned long) fds[i],
+ seed.value),
+ match_fd, (void *) (unsigned long) fds[i],
+ &iter);
+ node = cds_lfht_iter_get_node(&iter);
+ if (!node) {
+ /* Unknown file descriptor. */
+ WARN("Untracked file descriptor %d passed to fd_tracker_close_unsuspendable_fd()",
+ fds[i]);
+ ret = -EINVAL;
+ goto end_unlock;
+ }
+ entry = caa_container_of(
+ node, struct unsuspendable_fd, tracker_node);
+
+ cds_lfht_del(tracker->unsuspendable_fds, node);
+ unsuspendable_fd_destroy(entry);
+ fds[i] = -1;
+ }
+
+ tracker->count.unsuspendable -= fd_count;
+ ret = 0;
+end_unlock:
+ rcu_read_unlock();
+ pthread_mutex_unlock(&tracker->lock);
+ free(fds);
+end:
+ return ret;
+}
+
+/* Caller must have taken the tracker's and handle's locks. */
+static void fd_tracker_track(
+ struct fd_tracker *tracker, struct fs_handle_tracked *handle)
+{
+ if (handle->fd >= 0) {
+ tracker->count.suspendable.active++;
+ cds_list_add_tail(&handle->handles_list_node,
+ &tracker->active_handles);
+ } else {
+ tracker->count.suspendable.suspended++;
+ cds_list_add_tail(&handle->handles_list_node,
+ &tracker->suspended_handles);
+ }
+}
+
+/* Caller must have taken the tracker's and handle's locks. */
+static void fd_tracker_untrack(
+ struct fd_tracker *tracker, struct fs_handle_tracked *handle)
+{
+ if (handle->fd >= 0) {
+ tracker->count.suspendable.active--;
+ } else {
+ tracker->count.suspendable.suspended--;
+ }
+ cds_list_del(&handle->handles_list_node);
+}
+
+/* Caller must have taken the tracker's and handle's locks. */
+static int fd_tracker_restore_handle(
+ struct fd_tracker *tracker, struct fs_handle_tracked *handle)
+{
+ int ret;
+
+ fd_tracker_untrack(tracker, handle);
+ if (ACTIVE_COUNT(tracker) >= tracker->capacity) {
+ ret = fd_tracker_suspend_handles(tracker, 1);
+ if (ret) {
+ goto end;
+ }
+ }
+ ret = fs_handle_tracked_restore(handle);
+end:
+ fd_tracker_track(tracker, handle);
+ return ret ? ret : handle->fd;
+}
+
+static int fs_handle_tracked_get_fd(struct fs_handle *_handle)
+{
+ int ret;
+ struct fs_handle_tracked *handle =
+ container_of(_handle, struct fs_handle_tracked, parent);
+
+ /*
+ * TODO This should be optimized as it is a fairly hot path.
+ * The fd-tracker's lock should only be taken when a fs_handle is
+ * restored (slow path). On the fast path (fs_handle is active),
+ * the only effect on the fd_tracker is marking the handle as the
+ * most recently used. Currently, it is done by a call to the
+ * track/untrack helpers, but it should be done atomically.
+ *
+ * Note that the lock's nesting order must still be respected here.
+ * The handle's lock nests inside the tracker's lock.
+ */
+ pthread_mutex_lock(&handle->tracker->lock);
+ pthread_mutex_lock(&handle->lock);
+ LTTNG_ASSERT(!handle->in_use);
+
+ handle->tracker->stats.uses++;
+ if (handle->fd >= 0) {
+ ret = handle->fd;
+ /* Mark as most recently used. */
+ fd_tracker_untrack(handle->tracker, handle);
+ fd_tracker_track(handle->tracker, handle);
+ } else {
+ handle->tracker->stats.misses++;
+ ret = fd_tracker_restore_handle(handle->tracker, handle);
+ if (ret < 0) {
+ handle->tracker->stats.errors++;
+ goto end;
+ }
+ }
+ handle->in_use = true;
+end:
+ pthread_mutex_unlock(&handle->lock);
+ pthread_mutex_unlock(&handle->tracker->lock);
+ return ret;
+}
+
+static void fs_handle_tracked_put_fd(struct fs_handle *_handle)
+{
+ struct fs_handle_tracked *handle =
+ container_of(_handle, struct fs_handle_tracked, parent);
+
+ pthread_mutex_lock(&handle->lock);
+ handle->in_use = false;
+ pthread_mutex_unlock(&handle->lock);
+}
+
+static int fs_handle_tracked_unlink(struct fs_handle *_handle)
+{
+ int ret;
+ struct fs_handle_tracked *handle =
+ container_of(_handle, struct fs_handle_tracked, parent);
+
+ pthread_mutex_lock(&handle->tracker->lock);
+ pthread_mutex_lock(&handle->lock);
+ ret = lttng_inode_unlink(handle->inode);
+ pthread_mutex_unlock(&handle->lock);
+ pthread_mutex_unlock(&handle->tracker->lock);
+ return ret;
+}
+
+static int fs_handle_tracked_close(struct fs_handle *_handle)
+{
+ int ret = 0;
+ const char *path = NULL;
+ struct fs_handle_tracked *handle =
+ container_of(_handle, struct fs_handle_tracked, parent);
+ struct lttng_directory_handle *inode_directory_handle = NULL;
+
+ if (!handle) {
+ ret = -EINVAL;
+ goto end;
+ }
+
+ pthread_mutex_lock(&handle->tracker->lock);
+ pthread_mutex_lock(&handle->lock);
+ if (handle->inode) {
+ lttng_inode_borrow_location(handle->inode, NULL, &path);
+ /*
+ * Here a reference to the inode's directory handle is acquired
+ * to prevent the last reference to it from being released while
+ * the tracker's lock is taken.
+ *
+ * If this wasn't done, the directory handle could attempt to
+ * close its underlying directory file descriptor, which would
+ * attempt to lock the tracker's lock, resulting in a deadlock.
+ *
+ * Since a new reference to the directory handle is taken within
+ * the scope of this function, it is not possible for the last
+ * reference to the inode's location directory handle to be
+ * released during the call to lttng_inode_put().
+ *
+ * We wait until the tracker's lock is released to release the
+ * reference. Hence, the call to the tracker is delayed just
+ * enough to not attempt to recursively acquire the tracker's
+ * lock twice.
+ */
+ inode_directory_handle =
+ lttng_inode_get_location_directory_handle(
+ handle->inode);
+ }
+ fd_tracker_untrack(handle->tracker, handle);
+ if (handle->fd >= 0) {
+ /*
+ * The return value of close() is not propagated as there
+ * isn't much the user can do about it.
+ */
+ if (close(handle->fd)) {
+ PERROR("Failed to close the file descriptor (%d) of fs handle to %s, close() returned",
+ handle->fd, path ? path : "Unknown");
+ }
+ handle->fd = -1;
+ }
+ if (handle->inode) {
+ lttng_inode_put(handle->inode);
+ }
+ pthread_mutex_unlock(&handle->lock);
+ pthread_mutex_destroy(&handle->lock);
+ pthread_mutex_unlock(&handle->tracker->lock);
+ free(handle);
+ lttng_directory_handle_put(inode_directory_handle);
+end:
+ return ret;
+}
+++ /dev/null
-/*
- * Copyright (C) 2020 Jérémie Galarneau <jeremie.galarneau@efficios.com>
- *
- * SPDX-License-Identifier: GPL-2.0-only
- *
- */
-
-#include <common/defaults.h>
-#include <common/error.h>
-#include <common/hashtable/utils.h>
-#include <common/macros.h>
-#include <common/optional.h>
-#include <common/string-utils/format.h>
-#include <common/utils.h>
-#include <inttypes.h>
-#include <lttng/constant.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <unistd.h>
-#include <urcu.h>
-#include <urcu/rculfhash.h>
-#include <urcu/ref.h>
-
-#include "inode.h"
-
-struct inode_id {
- dev_t device;
- ino_t inode;
-};
-
-struct lttng_inode_registry {
- /* Hashtable of inode_id to lttng_inode. */
- struct cds_lfht *inodes;
-};
-
-struct lttng_inode {
- struct inode_id id;
- /* Node in the lttng_inode_registry's ht. */
- struct cds_lfht_node registry_node;
- /* Weak reference to ht containing the node. */
- struct cds_lfht *registry_ht;
- struct urcu_ref ref;
- struct rcu_head rcu_head;
- /* Location from which this file can be opened. */
- struct {
- struct lttng_directory_handle *directory_handle;
- char *path;
- } location;
- /* Unlink the underlying file at the release of the inode. */
- bool unlink_pending;
- LTTNG_OPTIONAL(unsigned int) unlinked_id;
- /* Weak reference. */
- struct lttng_unlinked_file_pool *unlinked_file_pool;
-};
-
-struct lttng_unlinked_file_pool {
- struct lttng_directory_handle *unlink_directory_handle;
- char *unlink_directory_path;
- unsigned int file_count;
- unsigned int next_id;
-};
-
-static struct {
- pthread_mutex_t lock;
- bool initialized;
- unsigned long value;
-} seed = {
- .lock = PTHREAD_MUTEX_INITIALIZER,
-};
-
-static unsigned long lttng_inode_id_hash(const struct inode_id *id)
-{
- uint64_t device = id->device, inode_no = id->inode;
-
- return hash_key_u64(&device, seed.value) ^
- hash_key_u64(&inode_no, seed.value);
-}
-
-static int lttng_inode_match(struct cds_lfht_node *node, const void *key)
-{
- const struct inode_id *id = key;
- const struct lttng_inode *inode = caa_container_of(
- node, struct lttng_inode, registry_node);
-
- return inode->id.device == id->device && inode->id.inode == id->inode;
-}
-
-static void lttng_inode_free(struct rcu_head *head)
-{
- struct lttng_inode *inode =
- caa_container_of(head, struct lttng_inode, rcu_head);
-
- free(inode);
-}
-
-static int lttng_unlinked_file_pool_add_inode(
- struct lttng_unlinked_file_pool *pool,
- struct lttng_inode *inode)
-{
- int ret;
- const unsigned int unlinked_id = pool->next_id++;
- char *inode_unlinked_name;
- bool reference_acquired;
-
- DBG("Adding inode of %s to unlinked file pool as id %u",
- inode->location.path, unlinked_id);
- ret = asprintf(&inode_unlinked_name, "%u", unlinked_id);
- if (ret < 0) {
- ERR("Failed to format unlinked inode name");
- ret = -1;
- goto end;
- }
-
- if (pool->file_count == 0) {
- DBG("Creating unlinked files directory at %s",
- pool->unlink_directory_path);
- LTTNG_ASSERT(!pool->unlink_directory_handle);
- ret = utils_mkdir(pool->unlink_directory_path,
- S_IRWXU | S_IRWXG, -1, -1);
- if (ret) {
- if (errno == EEXIST) {
- /*
- * Unexpected (previous crash?), but not an
- * error.
- */
- DBG("Unlinked file directory \"%s\" already exists",
- pool->unlink_directory_path);
- } else {
- PERROR("Failed to create unlinked files directory at %s",
- pool->unlink_directory_path);
- goto end;
- }
- }
- pool->unlink_directory_handle = lttng_directory_handle_create(
- pool->unlink_directory_path);
- if (!pool->unlink_directory_handle) {
- ERR("Failed to create directory handle to unlinked file pool at %s",
- pool->unlink_directory_path);
- ret = -1;
- goto end;
- }
- }
-
- ret = lttng_directory_handle_rename(inode->location.directory_handle,
- inode->location.path, pool->unlink_directory_handle,
- inode_unlinked_name);
- if (ret) {
- goto end;
- }
-
- lttng_directory_handle_put(inode->location.directory_handle);
- inode->location.directory_handle = NULL;
- reference_acquired = lttng_directory_handle_get(
- pool->unlink_directory_handle);
- LTTNG_ASSERT(reference_acquired);
- inode->location.directory_handle = pool->unlink_directory_handle;
-
- free(inode->location.path);
- inode->location.path = inode_unlinked_name;
- inode_unlinked_name = NULL;
- LTTNG_OPTIONAL_SET(&inode->unlinked_id, unlinked_id);
- pool->file_count++;
-end:
- free(inode_unlinked_name);
- return ret;
-}
-
-static int lttng_unlinked_file_pool_remove_inode(
- struct lttng_unlinked_file_pool *pool,
- struct lttng_inode *inode)
-{
- int ret;
-
- DBG("Removing inode with unlinked id %u from unlinked file pool",
- LTTNG_OPTIONAL_GET(inode->unlinked_id));
-
- ret = lttng_directory_handle_unlink_file(
- inode->location.directory_handle, inode->location.path);
- if (ret) {
- PERROR("Failed to unlink file %s from unlinked file directory",
- inode->location.path);
- goto end;
- }
- free(inode->location.path);
- inode->location.path = NULL;
- lttng_directory_handle_put(inode->location.directory_handle);
- inode->location.directory_handle = NULL;
-
- pool->file_count--;
- if (pool->file_count == 0) {
- ret = utils_recursive_rmdir(pool->unlink_directory_path);
- if (ret) {
- /*
- * There is nothing the caller can do, don't report an
- * error except through logging.
- */
- PERROR("Failed to remove unlinked files directory at %s",
- pool->unlink_directory_path);
- }
- lttng_directory_handle_put(pool->unlink_directory_handle);
- pool->unlink_directory_handle = NULL;
- }
-end:
- return ret;
-}
-
-static void lttng_inode_destroy(struct lttng_inode *inode)
-{
- if (!inode) {
- return;
- }
-
- rcu_read_lock();
- cds_lfht_del(inode->registry_ht, &inode->registry_node);
- rcu_read_unlock();
-
- if (inode->unlink_pending) {
- int ret;
-
- LTTNG_ASSERT(inode->location.directory_handle);
- LTTNG_ASSERT(inode->location.path);
- DBG("Removing %s from unlinked file pool",
- inode->location.path);
- ret = lttng_unlinked_file_pool_remove_inode(inode->unlinked_file_pool, inode);
- if (ret) {
- PERROR("Failed to unlink %s", inode->location.path);
- }
- }
-
- lttng_directory_handle_put(
- inode->location.directory_handle);
- inode->location.directory_handle = NULL;
- free(inode->location.path);
- inode->location.path = NULL;
- call_rcu(&inode->rcu_head, lttng_inode_free);
-}
-
-static void lttng_inode_release(struct urcu_ref *ref)
-{
- lttng_inode_destroy(caa_container_of(ref, struct lttng_inode, ref));
-}
-
-static void lttng_inode_get(struct lttng_inode *inode)
-{
- urcu_ref_get(&inode->ref);
-}
-
-struct lttng_unlinked_file_pool *lttng_unlinked_file_pool_create(
- const char *path)
-{
- struct lttng_unlinked_file_pool *pool = zmalloc(sizeof(*pool));
-
- if (!pool) {
- goto error;
- }
-
- if (!path || *path != '/') {
- ERR("Unlinked file pool must be created with an absolute path, path = \"%s\"",
- path ? path : "NULL");
- goto error;
- }
-
- pool->unlink_directory_path = strdup(path);
- if (!pool->unlink_directory_path) {
- PERROR("Failed to allocation unlinked file pool path");
- goto error;
- }
- DBG("Unlinked file pool created at: %s", path);
- return pool;
-error:
- lttng_unlinked_file_pool_destroy(pool);
- return NULL;
-}
-
-void lttng_unlinked_file_pool_destroy(
- struct lttng_unlinked_file_pool *pool)
-{
- if (!pool) {
- return;
- }
-
- LTTNG_ASSERT(pool->file_count == 0);
- lttng_directory_handle_put(pool->unlink_directory_handle);
- free(pool->unlink_directory_path);
- free(pool);
-}
-
-void lttng_inode_put(struct lttng_inode *inode)
-{
- urcu_ref_put(&inode->ref, lttng_inode_release);
-}
-
-struct lttng_directory_handle *
-lttng_inode_get_location_directory_handle(
- struct lttng_inode *inode)
-{
- if (inode->location.directory_handle) {
- const bool reference_acquired = lttng_directory_handle_get(
- inode->location.directory_handle);
-
- LTTNG_ASSERT(reference_acquired);
- }
- return inode->location.directory_handle;
-}
-
-void lttng_inode_borrow_location(struct lttng_inode *inode,
- const struct lttng_directory_handle **out_directory_handle,
- const char **out_path)
-{
- if (out_directory_handle) {
- *out_directory_handle = inode->location.directory_handle;
- }
- if (out_path) {
- *out_path = inode->location.path;
- }
-}
-
-int lttng_inode_rename(
- struct lttng_inode *inode,
- struct lttng_directory_handle *old_directory_handle,
- const char *old_path,
- struct lttng_directory_handle *new_directory_handle,
- const char *new_path,
- bool overwrite)
-{
- int ret = 0;
- char *new_path_copy = strdup(new_path);
- bool reference_acquired;
-
- DBG("Performing rename of inode from %s to %s with %s directory handles",
- old_path, new_path,
- lttng_directory_handle_equals(old_directory_handle,
- new_directory_handle) ?
- "identical" :
- "different");
-
- if (!new_path_copy) {
- ret = -ENOMEM;
- goto end;
- }
-
- if (inode->unlink_pending) {
- WARN("An attempt to rename an unlinked file from %s to %s has been performed",
- old_path, new_path);
- ret = -ENOENT;
- goto end;
- }
-
- if (!overwrite) {
- /* Verify that file doesn't exist. */
- struct stat statbuf;
-
- ret = lttng_directory_handle_stat(
- new_directory_handle, new_path, &statbuf);
- if (ret == 0) {
- ERR("Refusing to rename %s as the destination already exists",
- old_path);
- ret = -EEXIST;
- goto end;
- } else if (ret < 0 && errno != ENOENT) {
- PERROR("Failed to stat() %s", new_path);
- ret = -errno;
- goto end;
- }
- }
-
- ret = lttng_directory_handle_rename(old_directory_handle, old_path,
- new_directory_handle, new_path);
- if (ret) {
- PERROR("Failed to rename file %s to %s", old_path, new_path);
- ret = -errno;
- goto end;
- }
-
- reference_acquired = lttng_directory_handle_get(new_directory_handle);
- LTTNG_ASSERT(reference_acquired);
- lttng_directory_handle_put(inode->location.directory_handle);
- free(inode->location.path);
- inode->location.directory_handle = new_directory_handle;
- /* Ownership transferred. */
- inode->location.path = new_path_copy;
- new_path_copy = NULL;
-end:
- free(new_path_copy);
- return ret;
-}
-
-int lttng_inode_unlink(struct lttng_inode *inode)
-{
- int ret = 0;
-
- DBG("Attempting unlink of inode %s", inode->location.path);
-
- if (inode->unlink_pending) {
- WARN("An attempt to re-unlink %s has been performed, ignoring.",
- inode->location.path);
- ret = -ENOENT;
- goto end;
- }
-
- /*
- * Move to the temporary "deleted" directory until all
- * references are released.
- */
- ret = lttng_unlinked_file_pool_add_inode(
- inode->unlinked_file_pool, inode);
- if (ret) {
- PERROR("Failed to add inode \"%s\" to the unlinked file pool",
- inode->location.path);
- goto end;
- }
- inode->unlink_pending = true;
-end:
- return ret;
-}
-
-static struct lttng_inode *lttng_inode_create(const struct inode_id *id,
- struct cds_lfht *ht,
- struct lttng_unlinked_file_pool *unlinked_file_pool,
- struct lttng_directory_handle *directory_handle,
- const char *path)
-{
- struct lttng_inode *inode = NULL;
- char *path_copy;
- bool reference_acquired;
-
- path_copy = strdup(path);
- if (!path_copy) {
- goto end;
- }
-
- reference_acquired = lttng_directory_handle_get(directory_handle);
- LTTNG_ASSERT(reference_acquired);
-
- inode = zmalloc(sizeof(*inode));
- if (!inode) {
- goto end;
- }
-
- urcu_ref_init(&inode->ref);
- cds_lfht_node_init(&inode->registry_node);
- inode->id = *id;
- inode->registry_ht = ht;
- inode->unlinked_file_pool = unlinked_file_pool;
- /* Ownership of path copy is transferred to inode. */
- inode->location.path = path_copy;
- path_copy = NULL;
- inode->location.directory_handle = directory_handle;
-end:
- free(path_copy);
- return inode;
-}
-
-struct lttng_inode_registry *lttng_inode_registry_create(void)
-{
- struct lttng_inode_registry *registry = zmalloc(sizeof(*registry));
-
- if (!registry) {
- goto end;
- }
-
- pthread_mutex_lock(&seed.lock);
- if (!seed.initialized) {
- seed.value = (unsigned long) time(NULL);
- seed.initialized = true;
- }
- pthread_mutex_unlock(&seed.lock);
-
- registry->inodes = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0,
- CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
- if (!registry->inodes) {
- goto error;
- }
-end:
- return registry;
-error:
- lttng_inode_registry_destroy(registry);
- return NULL;
-}
-
-void lttng_inode_registry_destroy(
- struct lttng_inode_registry *registry)
-{
- if (!registry) {
- return;
- }
- if (registry->inodes) {
- int ret = cds_lfht_destroy(registry->inodes, NULL);
-
- LTTNG_ASSERT(!ret);
- }
- free(registry);
-}
-
-struct lttng_inode *lttng_inode_registry_get_inode(
- struct lttng_inode_registry *registry,
- struct lttng_directory_handle *handle,
- const char *path,
- int fd,
- struct lttng_unlinked_file_pool *unlinked_file_pool)
-{
- int ret;
- struct stat statbuf;
- struct inode_id id;
- struct cds_lfht_iter iter;
- struct cds_lfht_node *node;
- struct lttng_inode *inode = NULL;
-
- ret = fstat(fd, &statbuf);
- if (ret < 0) {
- PERROR("stat() failed on fd %i", fd);
- goto end;
- }
-
- id.device = statbuf.st_dev;
- id.inode = statbuf.st_ino;
-
- rcu_read_lock();
- cds_lfht_lookup(registry->inodes, lttng_inode_id_hash(&id),
- lttng_inode_match, &id, &iter);
- node = cds_lfht_iter_get_node(&iter);
- if (node) {
- inode = caa_container_of(
- node, struct lttng_inode, registry_node);
- lttng_inode_get(inode);
- goto end_unlock;
- }
-
- inode = lttng_inode_create(&id, registry->inodes, unlinked_file_pool,
- handle, path);
- if (!inode) {
- goto end_unlock;
- }
-
- node = cds_lfht_add_unique(registry->inodes,
- lttng_inode_id_hash(&inode->id), lttng_inode_match,
- &inode->id, &inode->registry_node);
- LTTNG_ASSERT(node == &inode->registry_node);
-end_unlock:
- rcu_read_unlock();
-end:
- return inode;
-}
--- /dev/null
+/*
+ * Copyright (C) 2020 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#include <common/defaults.h>
+#include <common/error.h>
+#include <common/hashtable/utils.h>
+#include <common/macros.h>
+#include <common/optional.h>
+#include <common/string-utils/format.h>
+#include <common/utils.h>
+#include <inttypes.h>
+#include <lttng/constant.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <urcu.h>
+#include <urcu/rculfhash.h>
+#include <urcu/ref.h>
+
+#include "inode.h"
+
+struct inode_id {
+ dev_t device;
+ ino_t inode;
+};
+
+struct lttng_inode_registry {
+ /* Hashtable of inode_id to lttng_inode. */
+ struct cds_lfht *inodes;
+};
+
+struct lttng_inode {
+ struct inode_id id;
+ /* Node in the lttng_inode_registry's ht. */
+ struct cds_lfht_node registry_node;
+ /* Weak reference to ht containing the node. */
+ struct cds_lfht *registry_ht;
+ struct urcu_ref ref;
+ struct rcu_head rcu_head;
+ /* Location from which this file can be opened. */
+ struct {
+ struct lttng_directory_handle *directory_handle;
+ char *path;
+ } location;
+ /* Unlink the underlying file at the release of the inode. */
+ bool unlink_pending;
+ LTTNG_OPTIONAL(unsigned int) unlinked_id;
+ /* Weak reference. */
+ struct lttng_unlinked_file_pool *unlinked_file_pool;
+};
+
+struct lttng_unlinked_file_pool {
+ struct lttng_directory_handle *unlink_directory_handle;
+ char *unlink_directory_path;
+ unsigned int file_count;
+ unsigned int next_id;
+};
+
+static struct {
+ pthread_mutex_t lock;
+ bool initialized;
+ unsigned long value;
+} seed = {
+ .lock = PTHREAD_MUTEX_INITIALIZER,
+};
+
+static unsigned long lttng_inode_id_hash(const struct inode_id *id)
+{
+ uint64_t device = id->device, inode_no = id->inode;
+
+ return hash_key_u64(&device, seed.value) ^
+ hash_key_u64(&inode_no, seed.value);
+}
+
+static int lttng_inode_match(struct cds_lfht_node *node, const void *key)
+{
+ const struct inode_id *id = (inode_id *) key;
+ const struct lttng_inode *inode = caa_container_of(
+ node, struct lttng_inode, registry_node);
+
+ return inode->id.device == id->device && inode->id.inode == id->inode;
+}
+
+static void lttng_inode_free(struct rcu_head *head)
+{
+ struct lttng_inode *inode =
+ caa_container_of(head, struct lttng_inode, rcu_head);
+
+ free(inode);
+}
+
+static int lttng_unlinked_file_pool_add_inode(
+ struct lttng_unlinked_file_pool *pool,
+ struct lttng_inode *inode)
+{
+ int ret;
+ const unsigned int unlinked_id = pool->next_id++;
+ char *inode_unlinked_name;
+ bool reference_acquired;
+
+ DBG("Adding inode of %s to unlinked file pool as id %u",
+ inode->location.path, unlinked_id);
+ ret = asprintf(&inode_unlinked_name, "%u", unlinked_id);
+ if (ret < 0) {
+ ERR("Failed to format unlinked inode name");
+ ret = -1;
+ goto end;
+ }
+
+ if (pool->file_count == 0) {
+ DBG("Creating unlinked files directory at %s",
+ pool->unlink_directory_path);
+ LTTNG_ASSERT(!pool->unlink_directory_handle);
+ ret = utils_mkdir(pool->unlink_directory_path,
+ S_IRWXU | S_IRWXG, -1, -1);
+ if (ret) {
+ if (errno == EEXIST) {
+ /*
+ * Unexpected (previous crash?), but not an
+ * error.
+ */
+ DBG("Unlinked file directory \"%s\" already exists",
+ pool->unlink_directory_path);
+ } else {
+ PERROR("Failed to create unlinked files directory at %s",
+ pool->unlink_directory_path);
+ goto end;
+ }
+ }
+ pool->unlink_directory_handle = lttng_directory_handle_create(
+ pool->unlink_directory_path);
+ if (!pool->unlink_directory_handle) {
+ ERR("Failed to create directory handle to unlinked file pool at %s",
+ pool->unlink_directory_path);
+ ret = -1;
+ goto end;
+ }
+ }
+
+ ret = lttng_directory_handle_rename(inode->location.directory_handle,
+ inode->location.path, pool->unlink_directory_handle,
+ inode_unlinked_name);
+ if (ret) {
+ goto end;
+ }
+
+ lttng_directory_handle_put(inode->location.directory_handle);
+ inode->location.directory_handle = NULL;
+ reference_acquired = lttng_directory_handle_get(
+ pool->unlink_directory_handle);
+ LTTNG_ASSERT(reference_acquired);
+ inode->location.directory_handle = pool->unlink_directory_handle;
+
+ free(inode->location.path);
+ inode->location.path = inode_unlinked_name;
+ inode_unlinked_name = NULL;
+ LTTNG_OPTIONAL_SET(&inode->unlinked_id, unlinked_id);
+ pool->file_count++;
+end:
+ free(inode_unlinked_name);
+ return ret;
+}
+
+static int lttng_unlinked_file_pool_remove_inode(
+ struct lttng_unlinked_file_pool *pool,
+ struct lttng_inode *inode)
+{
+ int ret;
+
+ DBG("Removing inode with unlinked id %u from unlinked file pool",
+ LTTNG_OPTIONAL_GET(inode->unlinked_id));
+
+ ret = lttng_directory_handle_unlink_file(
+ inode->location.directory_handle, inode->location.path);
+ if (ret) {
+ PERROR("Failed to unlink file %s from unlinked file directory",
+ inode->location.path);
+ goto end;
+ }
+ free(inode->location.path);
+ inode->location.path = NULL;
+ lttng_directory_handle_put(inode->location.directory_handle);
+ inode->location.directory_handle = NULL;
+
+ pool->file_count--;
+ if (pool->file_count == 0) {
+ ret = utils_recursive_rmdir(pool->unlink_directory_path);
+ if (ret) {
+ /*
+ * There is nothing the caller can do, don't report an
+ * error except through logging.
+ */
+ PERROR("Failed to remove unlinked files directory at %s",
+ pool->unlink_directory_path);
+ }
+ lttng_directory_handle_put(pool->unlink_directory_handle);
+ pool->unlink_directory_handle = NULL;
+ }
+end:
+ return ret;
+}
+
+static void lttng_inode_destroy(struct lttng_inode *inode)
+{
+ if (!inode) {
+ return;
+ }
+
+ rcu_read_lock();
+ cds_lfht_del(inode->registry_ht, &inode->registry_node);
+ rcu_read_unlock();
+
+ if (inode->unlink_pending) {
+ int ret;
+
+ LTTNG_ASSERT(inode->location.directory_handle);
+ LTTNG_ASSERT(inode->location.path);
+ DBG("Removing %s from unlinked file pool",
+ inode->location.path);
+ ret = lttng_unlinked_file_pool_remove_inode(inode->unlinked_file_pool, inode);
+ if (ret) {
+ PERROR("Failed to unlink %s", inode->location.path);
+ }
+ }
+
+ lttng_directory_handle_put(
+ inode->location.directory_handle);
+ inode->location.directory_handle = NULL;
+ free(inode->location.path);
+ inode->location.path = NULL;
+ call_rcu(&inode->rcu_head, lttng_inode_free);
+}
+
+static void lttng_inode_release(struct urcu_ref *ref)
+{
+ lttng_inode_destroy(caa_container_of(ref, struct lttng_inode, ref));
+}
+
+static void lttng_inode_get(struct lttng_inode *inode)
+{
+ urcu_ref_get(&inode->ref);
+}
+
+struct lttng_unlinked_file_pool *lttng_unlinked_file_pool_create(
+ const char *path)
+{
+ struct lttng_unlinked_file_pool *pool = (lttng_unlinked_file_pool *) zmalloc(sizeof(*pool));
+
+ if (!pool) {
+ goto error;
+ }
+
+ if (!path || *path != '/') {
+ ERR("Unlinked file pool must be created with an absolute path, path = \"%s\"",
+ path ? path : "NULL");
+ goto error;
+ }
+
+ pool->unlink_directory_path = strdup(path);
+ if (!pool->unlink_directory_path) {
+ PERROR("Failed to allocation unlinked file pool path");
+ goto error;
+ }
+ DBG("Unlinked file pool created at: %s", path);
+ return pool;
+error:
+ lttng_unlinked_file_pool_destroy(pool);
+ return NULL;
+}
+
+void lttng_unlinked_file_pool_destroy(
+ struct lttng_unlinked_file_pool *pool)
+{
+ if (!pool) {
+ return;
+ }
+
+ LTTNG_ASSERT(pool->file_count == 0);
+ lttng_directory_handle_put(pool->unlink_directory_handle);
+ free(pool->unlink_directory_path);
+ free(pool);
+}
+
+void lttng_inode_put(struct lttng_inode *inode)
+{
+ urcu_ref_put(&inode->ref, lttng_inode_release);
+}
+
+struct lttng_directory_handle *
+lttng_inode_get_location_directory_handle(
+ struct lttng_inode *inode)
+{
+ if (inode->location.directory_handle) {
+ const bool reference_acquired = lttng_directory_handle_get(
+ inode->location.directory_handle);
+
+ LTTNG_ASSERT(reference_acquired);
+ }
+ return inode->location.directory_handle;
+}
+
+void lttng_inode_borrow_location(struct lttng_inode *inode,
+ const struct lttng_directory_handle **out_directory_handle,
+ const char **out_path)
+{
+ if (out_directory_handle) {
+ *out_directory_handle = inode->location.directory_handle;
+ }
+ if (out_path) {
+ *out_path = inode->location.path;
+ }
+}
+
+int lttng_inode_rename(
+ struct lttng_inode *inode,
+ struct lttng_directory_handle *old_directory_handle,
+ const char *old_path,
+ struct lttng_directory_handle *new_directory_handle,
+ const char *new_path,
+ bool overwrite)
+{
+ int ret = 0;
+ char *new_path_copy = strdup(new_path);
+ bool reference_acquired;
+
+ DBG("Performing rename of inode from %s to %s with %s directory handles",
+ old_path, new_path,
+ lttng_directory_handle_equals(old_directory_handle,
+ new_directory_handle) ?
+ "identical" :
+ "different");
+
+ if (!new_path_copy) {
+ ret = -ENOMEM;
+ goto end;
+ }
+
+ if (inode->unlink_pending) {
+ WARN("An attempt to rename an unlinked file from %s to %s has been performed",
+ old_path, new_path);
+ ret = -ENOENT;
+ goto end;
+ }
+
+ if (!overwrite) {
+ /* Verify that file doesn't exist. */
+ struct stat statbuf;
+
+ ret = lttng_directory_handle_stat(
+ new_directory_handle, new_path, &statbuf);
+ if (ret == 0) {
+ ERR("Refusing to rename %s as the destination already exists",
+ old_path);
+ ret = -EEXIST;
+ goto end;
+ } else if (ret < 0 && errno != ENOENT) {
+ PERROR("Failed to stat() %s", new_path);
+ ret = -errno;
+ goto end;
+ }
+ }
+
+ ret = lttng_directory_handle_rename(old_directory_handle, old_path,
+ new_directory_handle, new_path);
+ if (ret) {
+ PERROR("Failed to rename file %s to %s", old_path, new_path);
+ ret = -errno;
+ goto end;
+ }
+
+ reference_acquired = lttng_directory_handle_get(new_directory_handle);
+ LTTNG_ASSERT(reference_acquired);
+ lttng_directory_handle_put(inode->location.directory_handle);
+ free(inode->location.path);
+ inode->location.directory_handle = new_directory_handle;
+ /* Ownership transferred. */
+ inode->location.path = new_path_copy;
+ new_path_copy = NULL;
+end:
+ free(new_path_copy);
+ return ret;
+}
+
+int lttng_inode_unlink(struct lttng_inode *inode)
+{
+ int ret = 0;
+
+ DBG("Attempting unlink of inode %s", inode->location.path);
+
+ if (inode->unlink_pending) {
+ WARN("An attempt to re-unlink %s has been performed, ignoring.",
+ inode->location.path);
+ ret = -ENOENT;
+ goto end;
+ }
+
+ /*
+ * Move to the temporary "deleted" directory until all
+ * references are released.
+ */
+ ret = lttng_unlinked_file_pool_add_inode(
+ inode->unlinked_file_pool, inode);
+ if (ret) {
+ PERROR("Failed to add inode \"%s\" to the unlinked file pool",
+ inode->location.path);
+ goto end;
+ }
+ inode->unlink_pending = true;
+end:
+ return ret;
+}
+
+static struct lttng_inode *lttng_inode_create(const struct inode_id *id,
+ struct cds_lfht *ht,
+ struct lttng_unlinked_file_pool *unlinked_file_pool,
+ struct lttng_directory_handle *directory_handle,
+ const char *path)
+{
+ struct lttng_inode *inode = NULL;
+ char *path_copy;
+ bool reference_acquired;
+
+ path_copy = strdup(path);
+ if (!path_copy) {
+ goto end;
+ }
+
+ reference_acquired = lttng_directory_handle_get(directory_handle);
+ LTTNG_ASSERT(reference_acquired);
+
+ inode = (lttng_inode *) zmalloc(sizeof(*inode));
+ if (!inode) {
+ goto end;
+ }
+
+ urcu_ref_init(&inode->ref);
+ cds_lfht_node_init(&inode->registry_node);
+ inode->id = *id;
+ inode->registry_ht = ht;
+ inode->unlinked_file_pool = unlinked_file_pool;
+ /* Ownership of path copy is transferred to inode. */
+ inode->location.path = path_copy;
+ path_copy = NULL;
+ inode->location.directory_handle = directory_handle;
+end:
+ free(path_copy);
+ return inode;
+}
+
+struct lttng_inode_registry *lttng_inode_registry_create(void)
+{
+ struct lttng_inode_registry *registry = (lttng_inode_registry *) zmalloc(sizeof(*registry));
+
+ if (!registry) {
+ goto end;
+ }
+
+ pthread_mutex_lock(&seed.lock);
+ if (!seed.initialized) {
+ seed.value = (unsigned long) time(NULL);
+ seed.initialized = true;
+ }
+ pthread_mutex_unlock(&seed.lock);
+
+ registry->inodes = cds_lfht_new(DEFAULT_HT_SIZE, 1, 0,
+ CDS_LFHT_AUTO_RESIZE | CDS_LFHT_ACCOUNTING, NULL);
+ if (!registry->inodes) {
+ goto error;
+ }
+end:
+ return registry;
+error:
+ lttng_inode_registry_destroy(registry);
+ return NULL;
+}
+
+void lttng_inode_registry_destroy(
+ struct lttng_inode_registry *registry)
+{
+ if (!registry) {
+ return;
+ }
+ if (registry->inodes) {
+ int ret = cds_lfht_destroy(registry->inodes, NULL);
+
+ LTTNG_ASSERT(!ret);
+ }
+ free(registry);
+}
+
+struct lttng_inode *lttng_inode_registry_get_inode(
+ struct lttng_inode_registry *registry,
+ struct lttng_directory_handle *handle,
+ const char *path,
+ int fd,
+ struct lttng_unlinked_file_pool *unlinked_file_pool)
+{
+ int ret;
+ struct stat statbuf;
+ struct inode_id id;
+ struct cds_lfht_iter iter;
+ struct cds_lfht_node *node;
+ struct lttng_inode *inode = NULL;
+
+ ret = fstat(fd, &statbuf);
+ if (ret < 0) {
+ PERROR("stat() failed on fd %i", fd);
+ goto end;
+ }
+
+ id.device = statbuf.st_dev;
+ id.inode = statbuf.st_ino;
+
+ rcu_read_lock();
+ cds_lfht_lookup(registry->inodes, lttng_inode_id_hash(&id),
+ lttng_inode_match, &id, &iter);
+ node = cds_lfht_iter_get_node(&iter);
+ if (node) {
+ inode = caa_container_of(
+ node, struct lttng_inode, registry_node);
+ lttng_inode_get(inode);
+ goto end_unlock;
+ }
+
+ inode = lttng_inode_create(&id, registry->inodes, unlinked_file_pool,
+ handle, path);
+ if (!inode) {
+ goto end_unlock;
+ }
+
+ node = cds_lfht_add_unique(registry->inodes,
+ lttng_inode_id_hash(&inode->id), lttng_inode_match,
+ &inode->id, &inode->registry_node);
+ LTTNG_ASSERT(node == &inode->registry_node);
+end_unlock:
+ rcu_read_unlock();
+end:
+ return inode;
+}
+++ /dev/null
-/*
- * Copyright (C) 2018 Jérémie Galarneau <jeremie.galarneau@efficios.com>
- *
- * SPDX-License-Identifier: GPL-2.0-only
- *
- */
-
-#include <common/compat/poll.h>
-
-#include "utils.h"
-
-#if HAVE_EPOLL
-
-struct create_args {
- struct lttng_poll_event *events;
- int size;
- int flags;
-};
-
-static int open_epoll(void *data, int *out_fd)
-{
- int ret;
- struct create_args *args = data;
-
- ret = lttng_poll_create(args->events, args->size, args->flags);
- if (ret < 0) {
- goto end;
- }
-
- *out_fd = args->events->epfd;
-end:
- return ret;
-}
-
-static int close_epoll(void *data, int *in_fd)
-{
- /* Will close the epfd. */
- lttng_poll_clean((struct lttng_poll_event *) data);
- return 0;
-}
-
-/*
- * The epoll variant of the poll compat layer creates an unsuspendable fd which
- * must be tracked.
- */
-int fd_tracker_util_poll_create(struct fd_tracker *tracker,
- const char *name,
- struct lttng_poll_event *events,
- int size,
- int flags)
-{
- int out_fd;
- struct create_args create_args = {
- .events = events,
- .size = size,
- .flags = flags,
- };
-
- return fd_tracker_open_unsuspendable_fd(
- tracker, &out_fd, &name, 1, open_epoll, &create_args);
-}
-
-int fd_tracker_util_poll_clean(
- struct fd_tracker *tracker, struct lttng_poll_event *events)
-{
- return fd_tracker_close_unsuspendable_fd(
- tracker, &events->epfd, 1, close_epoll, events);
-}
-
-#else /* HAVE_EPOLL */
-
-/*
- * The epoll variant of the poll compat layer creates an unsuspendable fd which
- * must be tracked.
- */
-int fd_tracker_util_poll_create(struct fd_tracker *tracker,
- const char *name,
- struct lttng_poll_event *events,
- int size,
- int flags)
-{
- return lttng_poll_create(events, size, flags);
-}
-
-int fd_tracker_util_poll_clean(
- struct fd_tracker *tracker, struct lttng_poll_event *events)
-{
- lttng_poll_clean(events);
- return 0;
-}
-
-#endif /* !HAVE_EPOLL */
--- /dev/null
+/*
+ * Copyright (C) 2018 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#include <common/compat/poll.h>
+
+#include "utils.h"
+
+#if HAVE_EPOLL
+
+struct create_args {
+ struct lttng_poll_event *events;
+ int size;
+ int flags;
+};
+
+static int open_epoll(void *data, int *out_fd)
+{
+ int ret;
+ struct create_args *args = (create_args *) data;
+
+ ret = lttng_poll_create(args->events, args->size, args->flags);
+ if (ret < 0) {
+ goto end;
+ }
+
+ *out_fd = args->events->epfd;
+end:
+ return ret;
+}
+
+static int close_epoll(void *data, int *in_fd)
+{
+ /* Will close the epfd. */
+ lttng_poll_clean((struct lttng_poll_event *) data);
+ return 0;
+}
+
+/*
+ * The epoll variant of the poll compat layer creates an unsuspendable fd which
+ * must be tracked.
+ */
+int fd_tracker_util_poll_create(struct fd_tracker *tracker,
+ const char *name,
+ struct lttng_poll_event *events,
+ int size,
+ int flags)
+{
+ int out_fd;
+ struct create_args create_args = {
+ .events = events,
+ .size = size,
+ .flags = flags,
+ };
+
+ return fd_tracker_open_unsuspendable_fd(
+ tracker, &out_fd, &name, 1, open_epoll, &create_args);
+}
+
+int fd_tracker_util_poll_clean(
+ struct fd_tracker *tracker, struct lttng_poll_event *events)
+{
+ return fd_tracker_close_unsuspendable_fd(
+ tracker, &events->epfd, 1, close_epoll, events);
+}
+
+#else /* HAVE_EPOLL */
+
+/*
+ * The epoll variant of the poll compat layer creates an unsuspendable fd which
+ * must be tracked.
+ */
+int fd_tracker_util_poll_create(struct fd_tracker *tracker,
+ const char *name,
+ struct lttng_poll_event *events,
+ int size,
+ int flags)
+{
+ return lttng_poll_create(events, size, flags);
+}
+
+int fd_tracker_util_poll_clean(
+ struct fd_tracker *tracker, struct lttng_poll_event *events)
+{
+ lttng_poll_clean(events);
+ return 0;
+}
+
+#endif /* !HAVE_EPOLL */
+++ /dev/null
-/*
- * Copyright (C) 2018 Jérémie Galarneau <jeremie.galarneau@efficios.com>
- *
- * SPDX-License-Identifier: GPL-2.0-only
- *
- */
-
-#include <common/error.h>
-#include <common/fd-tracker/utils.h>
-#include <common/utils.h>
-#include <lttng/constant.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <unistd.h>
-
-static
-int open_pipe_cloexec(void *data, int *fds)
-{
- return utils_create_pipe_cloexec(fds);
-}
-
-static
-int close_pipe(void *data, int *pipe)
-{
- utils_close_pipe(pipe);
- pipe[0] = pipe[1] = -1;
- return 0;
-}
-
-int fd_tracker_util_close_fd(void *unused, int *fd)
-{
- return close(*fd);
-}
-
-int fd_tracker_util_pipe_open_cloexec(
- struct fd_tracker *tracker, const char *name, int *pipe)
-{
- int ret;
- const char *name_prefix;
- char *names[2];
-
- name_prefix = name ? name : "Unknown pipe";
- ret = asprintf(&names[0], "%s (read end)", name_prefix);
- if (ret < 0) {
- goto end;
- }
- ret = asprintf(&names[1], "%s (write end)", name_prefix);
- if (ret < 0) {
- goto end;
- }
-
- ret = fd_tracker_open_unsuspendable_fd(tracker, pipe,
- (const char **) names, 2, open_pipe_cloexec, NULL);
- free(names[0]);
- free(names[1]);
-end:
- return ret;
-}
-
-int fd_tracker_util_pipe_close(struct fd_tracker *tracker, int *pipe)
-{
- return fd_tracker_close_unsuspendable_fd(
- tracker, pipe, 2, close_pipe, NULL);
-}
-
-struct open_directory_handle_args {
- const struct lttng_directory_handle *in_handle;
- struct lttng_directory_handle *ret_handle;
- const char *path;
-};
-
-static
-int open_directory_handle(void *_args, int *out_fds)
-{
- int ret = 0;
- struct open_directory_handle_args *args = _args;
- struct lttng_directory_handle *new_handle = NULL;
-
- new_handle = args->in_handle ?
- lttng_directory_handle_create_from_handle(
- args->path, args->in_handle) :
- lttng_directory_handle_create(args->path);
- if (!new_handle) {
- ret = -errno;
- goto end;
- }
-
- args->ret_handle = new_handle;
-
- /*
- * Reserved to indicate that the handle does not use a handle; there is
- * nothing to track. We want to indicate an error to the fd-tracker so
- * that it doesn't attempt to track the file descriptor, but also want
- * the caller to retrieve the newly-created handle.
- *
- * Calling this a hack is a fair assessment.
- */
- if (!lttng_directory_handle_uses_fd(new_handle)) {
- ret = ENOTSUP;
- } else {
-#ifdef HAVE_DIRFD
- *out_fds = new_handle->dirfd;
-#else
- abort();
-#endif
-
- }
-end:
- return ret;
-}
-
-#ifdef HAVE_DIRFD
-static
-int fd_close(void *unused, int *in_fds)
-{
- const int ret = close(in_fds[0]);
-
- in_fds[0] = -1;
- return ret;
-}
-
-static
-void directory_handle_destroy(
- struct lttng_directory_handle *handle, void *data)
-{
- struct fd_tracker *tracker = data;
- const int ret = fd_tracker_close_unsuspendable_fd(
- tracker, &handle->dirfd, 1, fd_close, NULL);
-
- if (ret) {
- ERR("Failed to untrack directory handle file descriptor");
- }
-}
-#endif
-
-struct lttng_directory_handle *fd_tracker_create_directory_handle(
- struct fd_tracker *tracker, const char *path)
-{
- return fd_tracker_create_directory_handle_from_handle(
- tracker, NULL, path);
-}
-
-struct lttng_directory_handle *fd_tracker_create_directory_handle_from_handle(
- struct fd_tracker *tracker,
- struct lttng_directory_handle *in_handle,
- const char *path)
-{
- int ret;
- int dirfd = -1;
- char *handle_name = NULL;
- char cwd_path[LTTNG_PATH_MAX] = "working directory";
- struct lttng_directory_handle *new_handle = NULL;
- struct open_directory_handle_args open_args = {
- .in_handle = in_handle,
- .path = path,
- };
-
- if (!path) {
- if (!getcwd(cwd_path, sizeof(cwd_path))) {
- PERROR("Failed to get current working directory to name directory handle");
- goto end;
- }
- }
-
- ret = asprintf(&handle_name, "Directory handle to %s",
- path ? path : cwd_path);
- if (ret < 0) {
- PERROR("Failed to format directory handle name");
- goto end;
- }
-
- ret = fd_tracker_open_unsuspendable_fd(tracker, &dirfd,
- (const char **) &handle_name, 1, open_directory_handle,
- &open_args);
- if (ret && ret != ENOTSUP) {
- ERR("Failed to open directory handle to %s through the fd tracker", path ? path : cwd_path);
- }
- new_handle = open_args.ret_handle;
-
-#ifdef HAVE_DIRFD
- new_handle->destroy_cb = directory_handle_destroy;
- new_handle->destroy_cb_data = tracker;
-#endif
-end:
- free(handle_name);
- return new_handle;
-}
--- /dev/null
+/*
+ * Copyright (C) 2018 Jérémie Galarneau <jeremie.galarneau@efficios.com>
+ *
+ * SPDX-License-Identifier: GPL-2.0-only
+ *
+ */
+
+#include <common/error.h>
+#include <common/fd-tracker/utils.h>
+#include <common/utils.h>
+#include <lttng/constant.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+
+static
+int open_pipe_cloexec(void *data, int *fds)
+{
+ return utils_create_pipe_cloexec(fds);
+}
+
+static
+int close_pipe(void *data, int *pipe)
+{
+ utils_close_pipe(pipe);
+ pipe[0] = pipe[1] = -1;
+ return 0;
+}
+
+int fd_tracker_util_close_fd(void *unused, int *fd)
+{
+ return close(*fd);
+}
+
+int fd_tracker_util_pipe_open_cloexec(
+ struct fd_tracker *tracker, const char *name, int *pipe)
+{
+ int ret;
+ const char *name_prefix;
+ char *names[2];
+
+ name_prefix = name ? name : "Unknown pipe";
+ ret = asprintf(&names[0], "%s (read end)", name_prefix);
+ if (ret < 0) {
+ goto end;
+ }
+ ret = asprintf(&names[1], "%s (write end)", name_prefix);
+ if (ret < 0) {
+ goto end;
+ }
+
+ ret = fd_tracker_open_unsuspendable_fd(tracker, pipe,
+ (const char **) names, 2, open_pipe_cloexec, NULL);
+ free(names[0]);
+ free(names[1]);
+end:
+ return ret;
+}
+
+int fd_tracker_util_pipe_close(struct fd_tracker *tracker, int *pipe)
+{
+ return fd_tracker_close_unsuspendable_fd(
+ tracker, pipe, 2, close_pipe, NULL);
+}
+
+struct open_directory_handle_args {
+ const struct lttng_directory_handle *in_handle;
+ struct lttng_directory_handle *ret_handle;
+ const char *path;
+};
+
+static
+int open_directory_handle(void *_args, int *out_fds)
+{
+ int ret = 0;
+ struct open_directory_handle_args *args = (open_directory_handle_args *) _args;
+ struct lttng_directory_handle *new_handle = NULL;
+
+ new_handle = args->in_handle ?
+ lttng_directory_handle_create_from_handle(
+ args->path, args->in_handle) :
+ lttng_directory_handle_create(args->path);
+ if (!new_handle) {
+ ret = -errno;
+ goto end;
+ }
+
+ args->ret_handle = new_handle;
+
+ /*
+ * Reserved to indicate that the handle does not use a handle; there is
+ * nothing to track. We want to indicate an error to the fd-tracker so
+ * that it doesn't attempt to track the file descriptor, but also want
+ * the caller to retrieve the newly-created handle.
+ *
+ * Calling this a hack is a fair assessment.
+ */
+ if (!lttng_directory_handle_uses_fd(new_handle)) {
+ ret = ENOTSUP;
+ } else {
+#ifdef HAVE_DIRFD
+ *out_fds = new_handle->dirfd;
+#else
+ abort();
+#endif
+
+ }
+end:
+ return ret;
+}
+
+#ifdef HAVE_DIRFD
+static
+int fd_close(void *unused, int *in_fds)
+{
+ const int ret = close(in_fds[0]);
+
+ in_fds[0] = -1;
+ return ret;
+}
+
+static
+void directory_handle_destroy(
+ struct lttng_directory_handle *handle, void *data)
+{
+ struct fd_tracker *tracker = (fd_tracker *) data;
+ const int ret = fd_tracker_close_unsuspendable_fd(
+ tracker, &handle->dirfd, 1, fd_close, NULL);
+
+ if (ret) {
+ ERR("Failed to untrack directory handle file descriptor");
+ }
+}
+#endif
+
+struct lttng_directory_handle *fd_tracker_create_directory_handle(
+ struct fd_tracker *tracker, const char *path)
+{
+ return fd_tracker_create_directory_handle_from_handle(
+ tracker, NULL, path);
+}
+
+struct lttng_directory_handle *fd_tracker_create_directory_handle_from_handle(
+ struct fd_tracker *tracker,
+ struct lttng_directory_handle *in_handle,
+ const char *path)
+{
+ int ret;
+ int dirfd = -1;
+ char *handle_name = NULL;
+ char cwd_path[LTTNG_PATH_MAX] = "working directory";
+ struct lttng_directory_handle *new_handle = NULL;
+ open_directory_handle_args open_args {};
+
+ open_args.in_handle = in_handle;
+ open_args.path = path;
+
+ if (!path) {
+ if (!getcwd(cwd_path, sizeof(cwd_path))) {
+ PERROR("Failed to get current working directory to name directory handle");
+ goto end;
+ }
+ }
+
+ ret = asprintf(&handle_name, "Directory handle to %s",
+ path ? path : cwd_path);
+ if (ret < 0) {
+ PERROR("Failed to format directory handle name");
+ goto end;
+ }
+
+ ret = fd_tracker_open_unsuspendable_fd(tracker, &dirfd,
+ (const char **) &handle_name, 1, open_directory_handle,
+ &open_args);
+ if (ret && ret != ENOTSUP) {
+ ERR("Failed to open directory handle to %s through the fd tracker", path ? path : cwd_path);
+ }
+ new_handle = open_args.ret_handle;
+
+#ifdef HAVE_DIRFD
+ new_handle->destroy_cb = directory_handle_destroy;
+ new_handle->destroy_cb_data = tracker;
+#endif
+end:
+ free(handle_name);
+ return new_handle;
+}
projects / lttng-tools.git / commitdiff
