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-rw-r--r--src/stat_cache.c668
1 files changed, 668 insertions, 0 deletions
diff --git a/src/stat_cache.c b/src/stat_cache.c
new file mode 100644
index 0000000..148f4c8
--- /dev/null
+++ b/src/stat_cache.c
@@ -0,0 +1,668 @@
+#define _GNU_SOURCE
+
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include <stdlib.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <assert.h>
+
+#include "log.h"
+#include "stat_cache.h"
+#include "fdevent.h"
+#include "etag.h"
+
+#ifdef HAVE_ATTR_ATTRIBUTES_H
+#include <attr/attributes.h>
+#endif
+
+#ifdef HAVE_FAM_H
+# include <fam.h>
+#endif
+
+#include "sys-mmap.h"
+
+/* NetBSD 1.3.x needs it */
+#ifndef MAP_FAILED
+# define MAP_FAILED -1
+#endif
+
+#ifndef O_LARGEFILE
+# define O_LARGEFILE 0
+#endif
+
+#ifndef HAVE_LSTAT
+#define lstat stat
+#endif
+
+#if 0
+/* enables debug code for testing if all nodes in the stat-cache as accessable */
+#define DEBUG_STAT_CACHE
+#endif
+
+/*
+ * stat-cache
+ *
+ * we cache the stat() calls in our own storage
+ * the directories are cached in FAM
+ *
+ * if we get a change-event from FAM, we increment the version in the FAM->dir mapping
+ *
+ * if the stat()-cache is queried we check if the version id for the directory is the
+ * same and return immediatly.
+ *
+ *
+ * What we need:
+ *
+ * - for each stat-cache entry we need a fast indirect lookup on the directory name
+ * - for each FAMRequest we have to find the version in the directory cache (index as userdata)
+ *
+ * stat <<-> directory <-> FAMRequest
+ *
+ * if file is deleted, directory is dirty, file is rechecked ...
+ * if directory is deleted, directory mapping is removed
+ *
+ * */
+
+#ifdef HAVE_FAM_H
+typedef struct {
+ FAMRequest *req;
+ FAMConnection *fc;
+
+ buffer *name;
+
+ int version;
+} fam_dir_entry;
+#endif
+
+/* the directory name is too long to always compare on it
+ * - we need a hash
+ * - the hash-key is used as sorting criteria for a tree
+ * - a splay-tree is used as we can use the caching effect of it
+ */
+
+/* we want to cleanup the stat-cache every few seconds, let's say 10
+ *
+ * - remove entries which are outdated since 30s
+ * - remove entries which are fresh but havn't been used since 60s
+ * - if we don't have a stat-cache entry for a directory, release it from the monitor
+ */
+
+#ifdef DEBUG_STAT_CACHE
+typedef struct {
+ int *ptr;
+
+ size_t used;
+ size_t size;
+} fake_keys;
+
+static fake_keys ctrl;
+#endif
+
+stat_cache *stat_cache_init(void) {
+ stat_cache *fc = NULL;
+
+ fc = calloc(1, sizeof(*fc));
+
+ fc->dir_name = buffer_init();
+#ifdef HAVE_FAM_H
+ fc->fam = calloc(1, sizeof(*fc->fam));
+#endif
+
+#ifdef DEBUG_STAT_CACHE
+ ctrl.size = 0;
+#endif
+
+ return fc;
+}
+
+static stat_cache_entry * stat_cache_entry_init(void) {
+ stat_cache_entry *sce = NULL;
+
+ sce = calloc(1, sizeof(*sce));
+
+ sce->name = buffer_init();
+ sce->etag = buffer_init();
+ sce->content_type = buffer_init();
+
+ return sce;
+}
+
+static void stat_cache_entry_free(void *data) {
+ stat_cache_entry *sce = data;
+ if (!sce) return;
+
+ buffer_free(sce->etag);
+ buffer_free(sce->name);
+ buffer_free(sce->content_type);
+
+ free(sce);
+}
+
+#ifdef HAVE_FAM_H
+static fam_dir_entry * fam_dir_entry_init(void) {
+ fam_dir_entry *fam_dir = NULL;
+
+ fam_dir = calloc(1, sizeof(*fam_dir));
+
+ fam_dir->name = buffer_init();
+
+ return fam_dir;
+}
+
+static void fam_dir_entry_free(void *data) {
+ fam_dir_entry *fam_dir = data;
+
+ if (!fam_dir) return;
+
+ FAMCancelMonitor(fam_dir->fc, fam_dir->req);
+
+ buffer_free(fam_dir->name);
+ free(fam_dir->req);
+
+ free(fam_dir);
+}
+#endif
+
+void stat_cache_free(stat_cache *sc) {
+ while (sc->files) {
+ int osize;
+ splay_tree *node = sc->files;
+
+ osize = sc->files->size;
+
+ stat_cache_entry_free(node->data);
+ sc->files = splaytree_delete(sc->files, node->key);
+
+ assert(osize - 1 == splaytree_size(sc->files));
+ }
+
+ buffer_free(sc->dir_name);
+
+#ifdef HAVE_FAM_H
+ while (sc->dirs) {
+ int osize;
+ splay_tree *node = sc->dirs;
+
+ osize = sc->dirs->size;
+
+ fam_dir_entry_free(node->data);
+ sc->dirs = splaytree_delete(sc->dirs, node->key);
+
+ if (osize == 1) {
+ assert(NULL == sc->dirs);
+ } else {
+ assert(osize == (sc->dirs->size + 1));
+ }
+ }
+
+ if (sc->fam) {
+ FAMClose(sc->fam);
+ free(sc->fam);
+ }
+#endif
+ free(sc);
+}
+
+#ifdef HAVE_XATTR
+static int stat_cache_attr_get(buffer *buf, char *name) {
+ int attrlen;
+ int ret;
+
+ attrlen = 1024;
+ buffer_prepare_copy(buf, attrlen);
+ attrlen--;
+ if(0 == (ret = attr_get(name, "Content-Type", buf->ptr, &attrlen, 0))) {
+ buf->used = attrlen + 1;
+ buf->ptr[attrlen] = '\0';
+ }
+ return ret;
+}
+#endif
+
+/* the famous DJB hash function for strings */
+static uint32_t hashme(buffer *str) {
+ uint32_t hash = 5381;
+ const char *s;
+ for (s = str->ptr; *s; s++) {
+ hash = ((hash << 5) + hash) + *s;
+ }
+
+ hash &= ~(1 << 31); /* strip the highest bit */
+
+ return hash;
+}
+
+#ifdef HAVE_FAM_H
+handler_t stat_cache_handle_fdevent(void *_srv, void *_fce, int revent) {
+ size_t i;
+ server *srv = _srv;
+ stat_cache *sc = srv->stat_cache;
+ size_t events;
+
+ UNUSED(_fce);
+ /* */
+
+ if ((revent & FDEVENT_IN) &&
+ sc->fam) {
+
+ events = FAMPending(sc->fam);
+
+ for (i = 0; i < events; i++) {
+ FAMEvent fe;
+ fam_dir_entry *fam_dir;
+ splay_tree *node;
+ int ndx;
+
+ FAMNextEvent(sc->fam, &fe);
+
+ /* handle event */
+
+ switch(fe.code) {
+ case FAMChanged:
+ case FAMDeleted:
+ case FAMMoved:
+ /* if the filename is a directory remove the entry */
+
+ fam_dir = fe.userdata;
+ fam_dir->version++;
+
+ /* file/dir is still here */
+ if (fe.code == FAMChanged) break;
+
+ buffer_copy_string(sc->dir_name, fe.filename);
+
+ ndx = hashme(sc->dir_name);
+
+ sc->dirs = splaytree_splay(sc->dirs, ndx);
+ node = sc->dirs;
+
+ if (node && (node->key == ndx)) {
+ int osize = splaytree_size(sc->dirs);
+
+ fam_dir_entry_free(node->data);
+ sc->dirs = splaytree_delete(sc->dirs, ndx);
+
+ assert(osize - 1 == splaytree_size(sc->dirs));
+ }
+ break;
+ default:
+ break;
+ }
+ }
+ }
+
+ if (revent & FDEVENT_HUP) {
+ /* fam closed the connection */
+ srv->stat_cache->fam_fcce_ndx = -1;
+
+ fdevent_event_del(srv->ev, &(sc->fam_fcce_ndx), FAMCONNECTION_GETFD(sc->fam));
+ fdevent_unregister(srv->ev, FAMCONNECTION_GETFD(sc->fam));
+
+ FAMClose(sc->fam);
+ free(sc->fam);
+
+ sc->fam = NULL;
+ }
+
+ return HANDLER_GO_ON;
+}
+
+static int buffer_copy_dirname(buffer *dst, buffer *file) {
+ size_t i;
+
+ if (buffer_is_empty(file)) return -1;
+
+ for (i = file->used - 1; i+1 > 0; i--) {
+ if (file->ptr[i] == '/') {
+ buffer_copy_string_len(dst, file->ptr, i);
+ return 0;
+ }
+ }
+
+ return -1;
+}
+#endif
+
+/***
+ *
+ *
+ *
+ * returns:
+ * - HANDLER_FINISHED on cache-miss (don't forget to reopen the file)
+ * - HANDLER_ERROR on stat() failed -> see errno for problem
+ */
+
+handler_t stat_cache_get_entry(server *srv, connection *con, buffer *name, stat_cache_entry **ret_sce) {
+#ifdef HAVE_FAM_H
+ fam_dir_entry *fam_dir = NULL;
+ int dir_ndx = -1;
+ splay_tree *dir_node = NULL;
+#endif
+ stat_cache_entry *sce = NULL;
+ stat_cache *sc;
+ struct stat st;
+ size_t k;
+ int fd;
+#ifdef DEBUG_STAT_CACHE
+ size_t i;
+#endif
+
+ int file_ndx;
+ splay_tree *file_node = NULL;
+
+ *ret_sce = NULL;
+
+ /*
+ * check if the directory for this file has changed
+ */
+
+ sc = srv->stat_cache;
+
+ file_ndx = hashme(name);
+ sc->files = splaytree_splay(sc->files, file_ndx);
+
+#ifdef DEBUG_STAT_CACHE
+ for (i = 0; i < ctrl.used; i++) {
+ if (ctrl.ptr[i] == file_ndx) break;
+ }
+#endif
+
+ if (sc->files && (sc->files->key == file_ndx)) {
+#ifdef DEBUG_STAT_CACHE
+ /* it was in the cache */
+ assert(i < ctrl.used);
+#endif
+
+ /* we have seen this file already and
+ * don't stat() it again in the same second */
+
+ file_node = sc->files;
+
+ sce = file_node->data;
+
+ /* check if the name is the same, we might have a collision */
+
+ if (buffer_is_equal(name, sce->name)) {
+ if (srv->srvconf.stat_cache_engine == STAT_CACHE_ENGINE_SIMPLE) {
+ if (sce->stat_ts == srv->cur_ts) {
+ *ret_sce = sce;
+ return HANDLER_GO_ON;
+ }
+ }
+ } else {
+ /* oops, a collision,
+ *
+ * file_node is used by the FAM check below to see if we know this file
+ * and if we can save a stat().
+ *
+ * BUT, the sce is not reset here as the entry into the cache is ok, we
+ * it is just not pointing to our requested file.
+ *
+ * */
+
+ file_node = NULL;
+ }
+ } else {
+#ifdef DEBUG_STAT_CACHE
+ if (i != ctrl.used) {
+ fprintf(stderr, "%s.%d: %08x was already inserted but not found in cache, %s\n", __FILE__, __LINE__, file_ndx, name->ptr);
+ }
+ assert(i == ctrl.used);
+#endif
+ }
+
+#ifdef HAVE_FAM_H
+ /* dir-check */
+ if (srv->srvconf.stat_cache_engine == STAT_CACHE_ENGINE_FAM) {
+ if (0 != buffer_copy_dirname(sc->dir_name, name)) {
+ SEGFAULT();
+ }
+
+ dir_ndx = hashme(sc->dir_name);
+
+ sc->dirs = splaytree_splay(sc->dirs, dir_ndx);
+
+ if (sc->dirs && (sc->dirs->key == dir_ndx)) {
+ dir_node = sc->dirs;
+ }
+
+ if (dir_node && file_node) {
+ /* we found a file */
+
+ sce = file_node->data;
+ fam_dir = dir_node->data;
+
+ if (fam_dir->version == sce->dir_version) {
+ /* the stat()-cache entry is still ok */
+
+ *ret_sce = sce;
+ return HANDLER_GO_ON;
+ }
+ }
+ }
+#endif
+
+ /*
+ * *lol*
+ * - open() + fstat() on a named-pipe results in a (intended) hang.
+ * - stat() if regualar file + open() to see if we can read from it is better
+ *
+ * */
+
+ if (-1 == stat(name->ptr, &st)) {
+ return HANDLER_ERROR;
+ }
+
+
+ if (S_ISREG(st.st_mode)) {
+ /* try to open the file to check if we can read it */
+ if (-1 == (fd = open(name->ptr, O_RDONLY))) {
+ return HANDLER_ERROR;
+ }
+ close(fd);
+ }
+
+ if (NULL == sce) {
+ int osize = 0;
+
+ if (sc->files) {
+ osize = sc->files->size;
+ }
+
+ sce = stat_cache_entry_init();
+ buffer_copy_string_buffer(sce->name, name);
+
+ sc->files = splaytree_insert(sc->files, file_ndx, sce);
+#ifdef DEBUG_STAT_CACHE
+ if (ctrl.size == 0) {
+ ctrl.size = 16;
+ ctrl.used = 0;
+ ctrl.ptr = malloc(ctrl.size * sizeof(*ctrl.ptr));
+ } else if (ctrl.size == ctrl.used) {
+ ctrl.size += 16;
+ ctrl.ptr = realloc(ctrl.ptr, ctrl.size * sizeof(*ctrl.ptr));
+ }
+
+ ctrl.ptr[ctrl.used++] = file_ndx;
+
+ assert(sc->files);
+ assert(sc->files->data == sce);
+ assert(osize + 1 == splaytree_size(sc->files));
+#endif
+ }
+
+ sce->st = st;
+ sce->stat_ts = srv->cur_ts;
+
+ /* catch the obvious symlinks
+ *
+ * this is not a secure check as we still have a race-condition between
+ * the stat() and the open. We can only solve this by
+ * 1. open() the file
+ * 2. fstat() the fd
+ *
+ * and keeping the file open for the rest of the time. But this can
+ * only be done at network level.
+ *
+ * */
+ if (S_ISLNK(st.st_mode) && !con->conf.follow_symlink) {
+ return HANDLER_ERROR;
+ }
+
+ if (S_ISREG(st.st_mode)) {
+ /* determine mimetype */
+ buffer_reset(sce->content_type);
+
+ for (k = 0; k < con->conf.mimetypes->used; k++) {
+ data_string *ds = (data_string *)con->conf.mimetypes->data[k];
+ buffer *type = ds->key;
+
+ if (type->used == 0) continue;
+
+ /* check if the right side is the same */
+ if (type->used > name->used) continue;
+
+ if (0 == strncasecmp(name->ptr + name->used - type->used, type->ptr, type->used - 1)) {
+ buffer_copy_string_buffer(sce->content_type, ds->value);
+ break;
+ }
+ }
+ etag_create(sce->etag, &(sce->st));
+#ifdef HAVE_XATTR
+ if (buffer_is_empty(sce->content_type)) {
+ stat_cache_attr_get(sce->content_type, name->ptr);
+ }
+#endif
+ }
+
+#ifdef HAVE_FAM_H
+ if (sc->fam &&
+ (srv->srvconf.stat_cache_engine == STAT_CACHE_ENGINE_FAM)) {
+ /* is this directory already registered ? */
+ if (!dir_node) {
+ fam_dir = fam_dir_entry_init();
+ fam_dir->fc = sc->fam;
+
+ buffer_copy_string_buffer(fam_dir->name, sc->dir_name);
+
+ fam_dir->version = 1;
+
+ fam_dir->req = calloc(1, sizeof(FAMRequest));
+
+ if (0 != FAMMonitorDirectory(sc->fam, fam_dir->name->ptr,
+ fam_dir->req, fam_dir)) {
+
+ log_error_write(srv, __FILE__, __LINE__, "sbs",
+ "monitoring dir failed:",
+ fam_dir->name,
+ FamErrlist[FAMErrno]);
+
+ fam_dir_entry_free(fam_dir);
+ } else {
+ int osize = 0;
+
+ if (sc->dirs) {
+ osize = sc->dirs->size;
+ }
+
+ sc->dirs = splaytree_insert(sc->dirs, dir_ndx, fam_dir);
+ assert(sc->dirs);
+ assert(sc->dirs->data == fam_dir);
+ assert(osize == (sc->dirs->size - 1));
+ }
+ } else {
+ fam_dir = dir_node->data;
+ }
+
+ /* bind the fam_fc to the stat() cache entry */
+
+ if (fam_dir) {
+ sce->dir_version = fam_dir->version;
+ sce->dir_ndx = dir_ndx;
+ }
+ }
+#endif
+
+ *ret_sce = sce;
+
+ return HANDLER_GO_ON;
+}
+
+/**
+ * remove stat() from cache which havn't been stat()ed for
+ * more than 10 seconds
+ *
+ *
+ * walk though the stat-cache, collect the ids which are too old
+ * and remove them in a second loop
+ */
+
+static int stat_cache_tag_old_entries(server *srv, splay_tree *t, int *keys, size_t *ndx) {
+ stat_cache_entry *sce;
+
+ if (!t) return 0;
+
+ stat_cache_tag_old_entries(srv, t->left, keys, ndx);
+ stat_cache_tag_old_entries(srv, t->right, keys, ndx);
+
+ sce = t->data;
+
+ if (srv->cur_ts - sce->stat_ts > 2) {
+ keys[(*ndx)++] = t->key;
+ }
+
+ return 0;
+}
+
+int stat_cache_trigger_cleanup(server *srv) {
+ stat_cache *sc;
+ size_t max_ndx = 0, i;
+ int *keys;
+
+ sc = srv->stat_cache;
+
+ if (!sc->files) return 0;
+
+ keys = calloc(1, sizeof(size_t) * sc->files->size);
+
+ stat_cache_tag_old_entries(srv, sc->files, keys, &max_ndx);
+
+ for (i = 0; i < max_ndx; i++) {
+ int ndx = keys[i];
+ splay_tree *node;
+
+ sc->files = splaytree_splay(sc->files, ndx);
+
+ node = sc->files;
+
+ if (node && (node->key == ndx)) {
+#ifdef DEBUG_STAT_CACHE
+ size_t j;
+ int osize = splaytree_size(sc->files);
+ stat_cache_entry *sce = node->data;
+#endif
+ stat_cache_entry_free(node->data);
+ sc->files = splaytree_delete(sc->files, ndx);
+
+#ifdef DEBUG_STAT_CACHE
+ for (j = 0; j < ctrl.used; j++) {
+ if (ctrl.ptr[j] == ndx) {
+ ctrl.ptr[j] = ctrl.ptr[--ctrl.used];
+ break;
+ }
+ }
+
+ assert(osize - 1 == splaytree_size(sc->files));
+#endif
+ }
+ }
+
+ free(keys);
+
+ return 0;
+}
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