--- /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;
+}
projects / lttng-tools.git / blobdiff