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lighttpd1.4/src/stat_cache.c

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#include "first.h"
#include "stat_cache.h"
#include "log.h"
#include "fdevent.h"
#include "http_etag.h"
#include "algo_splaytree.h"
#include <sys/types.h>
#include <sys/stat.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>
#include <unistd.h>
#include <fcntl.h>
#if defined(HAVE_SYS_XATTR_H)
# include <sys/xattr.h>
#elif defined(HAVE_ATTR_ATTRIBUTES_H)
# include <attr/attributes.h>
#endif
#ifdef HAVE_SYS_EXTATTR_H
# include <sys/extattr.h>
#endif
#ifndef HAVE_LSTAT
#define lstat stat
#ifndef S_ISLNK
#define S_ISLNK(mode) (0)
#endif
#endif
/*
* stat-cache
*
* - a splay-tree is used as we can use the caching effect of it
*/
enum {
STAT_CACHE_ENGINE_SIMPLE = 0 /*(default)*/
,STAT_CACHE_ENGINE_NONE = 1
,STAT_CACHE_ENGINE_FAM = 2 /* same as STAT_CACHE_ENGINE_INOTIFY */
,STAT_CACHE_ENGINE_INOTIFY = 2 /* same as STAT_CACHE_ENGINE_FAM */
,STAT_CACHE_ENGINE_KQUEUE = 2 /* same as STAT_CACHE_ENGINE_FAM */
};
struct stat_cache_fam; /* declaration */
typedef struct stat_cache {
int stat_cache_engine;
splay_tree *files; /* nodes of tree are (stat_cache_entry *) */
struct stat_cache_fam *scf;
} stat_cache;
static stat_cache sc;
static void * stat_cache_sptree_find(splay_tree ** const sptree,
const char * const name,
uint32_t len)
{
const int ndx = splaytree_djbhash(name, len);
*sptree = splaytree_splay(*sptree, ndx);
return (*sptree && (*sptree)->key == ndx) ? (*sptree)->data : NULL;
}
#if defined(HAVE_SYS_INOTIFY_H) \
|| (defined(HAVE_SYS_EVENT_H) && defined(HAVE_KQUEUE))
#ifndef HAVE_FAM_H
#define HAVE_FAM_H
#endif
#endif
#ifdef HAVE_FAM_H
/* monitor changes in directories using FAM
*
* This implementation employing FAM monitors directories as they are used,
* and maintains a reference count for cache use within stat_cache.c.
* A periodic job runs in lighttpd every 32 seconds, expiring entries unused
* in last 64 seconds out of the cache and cancelling FAM monitoring. Items
* within the cache are checked against the filesystem upon use if last stat()
* was greater than or equal to 16 seconds ago.
*
* This implementation does not monitor every directory in a tree, and therefore
* the cache may get out-of-sync with the filesystem. Delays in receiving and
* processing events from FAM might also lead to stale cache entries.
*
* For many websites, a large number of files are seldom, if ever, modified,
* and a common practice with images is to create a new file with a new name
* when a new version is needed, in order for client browsers and CDNs to better
* cache the content. Given this, most use will see little difference in
* performance between server.stat-cache-engine = "fam" and "simple" (default).
* The default server.stat-cache-engine = "simple" calls stat() on a target once
* per second, and reuses that information until the next second. For use where
* changes must be immediately visible, server.stat-cache-engine = "disable"
* should be used.
*
* When considering use of server.stat-cache-engine = "fam", there are a few
* additional limitations for this cache implementation using FAM.
* - symlinks to files located outside of the current directory do not result
* in changes to that file being monitored (unless that file is in a directory
* which is monitored as a result of a different request). symlinks can be
* chained and can be circular. This implementation *does not* readlink() or
* realpath() to resolve the chains to find and monitor the ultimate target
* directory. While symlinks to files located outside the current directory
* are not monitored, symlinks to directories *are* monitored, though chains
* of symlinks to directories do not result in monitoring of the directories
* containing intermediate symlinks to the target directory.
* - directory rename of a directory which is not currently being monitored will
* result in stale information in the cache if there is a subdirectory that is
* being monitored.
* Even though lighttpd will not receive FAM events in the above cases, lighttpd
* does re-validate the information in the cache upon use if the cache entry has
* not been checked in 16 seconds, so that is the upper limit for use of stale
* data.
*
* Use of server.stat-cache-engine = "fam" is discouraged for extremely volatile
* directories such as temporary directories (e.g. /tmp and maybe /var/tmp) due
* to the overhead of processing the additional noise generated from changes.
* Related, server.stat-cache-engine = "fam" is not recommended on trees of
* untrusted files where a malicious user could generate an excess of change
* events.
*
* Internal note: lighttpd walks the caches to prune trees in stat_cache when an
* event is received for a directory (or symlink to a directory) which has been
* deleted or renamed. The splaytree data structure is suboptimal for frequent
* changes of large directories trees where there have been a large number of
* different files recently accessed and part of the stat_cache.
*/
#if defined(HAVE_SYS_INOTIFY_H) \
&& !(defined(HAVE_SYS_EVENT_H) && defined(HAVE_KQUEUE))
#include <sys/inotify.h>
/*(translate FAM API to inotify; this is specific to stat_cache.c use of FAM)*/
#define fam fd /*(translate struct stat_cache_fam scf->fam -> scf->fd)*/
typedef int FAMRequest; /*(fr)*/
#define FAMClose(fd) \
close(*(fd))
#define FAMCancelMonitor(fd, wd) \
inotify_rm_watch(*(fd), *(wd))
#define fam_watch_mask ( IN_ATTRIB | IN_CREATE | IN_DELETE | IN_DELETE_SELF \
| IN_MODIFY | IN_MOVE_SELF | IN_MOVED_FROM \
| IN_EXCL_UNLINK | IN_ONLYDIR )
/*(note: follows symlinks; not providing IN_DONT_FOLLOW)*/
#define FAMMonitorDirectory(fd, fn, wd, userData) \
((*(wd) = inotify_add_watch(*(fd), (fn), (fam_watch_mask))) < 0)
typedef enum FAMCodes { /*(copied from fam.h to define arbitrary enum values)*/
FAMChanged=1,
FAMDeleted=2,
FAMCreated=5,
FAMMoved=6,
} FAMCodes;
#elif defined HAVE_SYS_EVENT_H && defined HAVE_KQUEUE
#undef HAVE_SYS_INOTIFY_H
#include <sys/event.h>
#include <sys/time.h>
/*(translate FAM API to inotify; this is specific to stat_cache.c use of FAM)*/
#define fam fd /*(translate struct stat_cache_fam scf->fam -> scf->fd)*/
typedef int FAMRequest; /*(fr)*/
#define FAMClose(fd) \
(-1 != (*(fd)) ? close(*(fd)) : 0)
static int FAMCancelMonitor (const int * const fd, int * const wd)
{
if (-1 == *fd) return 0;
if (-1 == *wd) return 0;
struct timespec t0 = { 0, 0 };
struct kevent kev;
EV_SET(&kev, *wd, EVFILT_VNODE, EV_DELETE, 0, 0, 0);
int rc = kevent(*fd, &kev, 1, NULL, 0, &t0);
close(*wd);
*wd = -1;
return rc;
}
static int FAMMonitorDirectory (int * const fd, char * const fn, int * const wd, void * const userData)
{
*wd = fdevent_open_dirname(fn, 1); /*(note: follows symlinks)*/
if (-1 == *wd) return -1;
struct timespec t0 = { 0, 0 };
struct kevent kev;
unsigned short kev_flags = EV_ADD | EV_ENABLE | EV_CLEAR;
unsigned int kev_fflags = NOTE_ATTRIB | NOTE_EXTEND | NOTE_LINK | NOTE_WRITE
| NOTE_DELETE | NOTE_REVOKE | NOTE_RENAME;
EV_SET(&kev, *wd, EVFILT_VNODE, kev_flags, kev_fflags, 0, userData);
return kevent(*fd, &kev, 1, NULL, 0, &t0);
}
typedef enum FAMCodes { /*(copied from fam.h to define arbitrary enum values)*/
FAMChanged=1,
FAMDeleted=2,
FAMCreated=5,
FAMMoved=6,
} FAMCodes;
#else
#include <fam.h>
#ifdef HAVE_FAMNOEXISTS
#ifndef LIGHTTPD_STATIC
#ifdef HAVE_DLFCN_H
#include <dlfcn.h>
#endif
#endif
#endif
#endif
typedef struct fam_dir_entry {
buffer name;
int refcnt;
FAMRequest req;
unix_time64_t stat_ts;
dev_t st_dev;
ino_t st_ino;
struct fam_dir_entry *fam_parent;
} fam_dir_entry;
typedef struct stat_cache_fam {
splay_tree *dirs; /* indexed by path; node data is fam_dir_entry */
#ifdef HAVE_SYS_INOTIFY_H
splay_tree *wds; /* indexed by inotify watch descriptor */
#elif defined HAVE_SYS_EVENT_H && defined HAVE_KQUEUE
#else
FAMConnection fam;
#endif
log_error_st *errh;
fdevents *ev;
fdnode *fdn;
int fd;
} stat_cache_fam;
__attribute_returns_nonnull__
static fam_dir_entry * fam_dir_entry_init(const char *name, size_t len)
{
fam_dir_entry * const fam_dir = calloc(1, sizeof(*fam_dir));
force_assert(NULL != fam_dir);
buffer_copy_string_len(&fam_dir->name, name, len);
fam_dir->refcnt = 0;
#if defined HAVE_SYS_EVENT_H && defined HAVE_KQUEUE
fam_dir->req = -1;
#endif
return fam_dir;
}
static void fam_dir_entry_free(fam_dir_entry *fam_dir)
{
if (!fam_dir) return;
/*(fam_dir->fam_parent might be invalid pointer here; ignore)*/
free(fam_dir->name.ptr);
#if defined HAVE_SYS_EVENT_H && defined HAVE_KQUEUE
if (-1 != fam_dir->req)
close(fam_dir->req);
#endif
free(fam_dir);
}
static void fam_dir_invalidate_node(fam_dir_entry *fam_dir)
{
fam_dir->stat_ts = 0;
if (fam_dir->fam_parent) {
--fam_dir->fam_parent->refcnt;
fam_dir->fam_parent = NULL;
}
}
/*
* walk though splay_tree and collect contents of dir tree.
* remove tagged entries in a second loop
*/
static void fam_dir_tag_refcnt(splay_tree *t, int *keys, int *ndx)
{
if (*ndx == 512) return; /*(must match num array entries in keys[])*/
if (t->left) fam_dir_tag_refcnt(t->left, keys, ndx);
if (t->right) fam_dir_tag_refcnt(t->right, keys, ndx);
if (*ndx == 512) return; /*(must match num array entries in keys[])*/
fam_dir_entry * const fam_dir = t->data;
if (0 == fam_dir->refcnt) {
fam_dir_invalidate_node(fam_dir);
keys[(*ndx)++] = t->key;
}
}
__attribute_noinline__
static void fam_dir_periodic_cleanup() {
stat_cache_fam * const scf = sc.scf;
int max_ndx, i;
int keys[512]; /* 2k size on stack */
#if defined HAVE_SYS_EVENT_H && defined HAVE_KQUEUE
struct kevent kevl[512]; /* 32k size on stack to batch kevent EV_DELETE */
#endif
do {
if (!scf->dirs) break;
max_ndx = 0;
fam_dir_tag_refcnt(scf->dirs, keys, &max_ndx);
for (i = 0; i < max_ndx; ++i) {
const int ndx = keys[i];
splay_tree *node = scf->dirs = splaytree_splay(scf->dirs, ndx);
if (node && node->key == ndx) {
fam_dir_entry *fam_dir = node->data;
scf->dirs = splaytree_delete(scf->dirs, ndx);
#ifdef HAVE_SYS_INOTIFY_H
scf->wds = splaytree_delete(scf->wds, fam_dir->req);
#elif defined HAVE_SYS_EVENT_H && defined HAVE_KQUEUE
/* batch process kevent removal; defer cancel */
EV_SET(kevl+i, fam_dir->req, EVFILT_VNODE, EV_DELETE, 0, 0, 0);
fam_dir->req = -1; /*(make FAMCancelMonitor() a no-op)*/
#endif
FAMCancelMonitor(&scf->fam, &fam_dir->req);
fam_dir_entry_free(fam_dir);
}
}
#if defined HAVE_SYS_EVENT_H && defined HAVE_KQUEUE
/* batch process: kevent() to submit EV_DELETE, then close dir fds */
if (0 == max_ndx) break;
struct timespec t0 = { 0, 0 };
kevent(scf->fd, kevl, max_ndx, NULL, 0, &t0);
for (i = 0; i < max_ndx; ++i)
close((int)kevl[i].ident);
#endif
} while (max_ndx == sizeof(keys)/sizeof(int));
}
static void fam_dir_invalidate_tree(splay_tree *t, const char *name, size_t len)
{
#ifdef __clang_analyzer__
force_assert(name);
#endif
/*force_assert(t);*/
if (t->left) fam_dir_invalidate_tree(t->left, name, len);
if (t->right) fam_dir_invalidate_tree(t->right, name, len);
fam_dir_entry * const fam_dir = t->data;
#ifdef __clang_analyzer__
force_assert(fam_dir);
#endif
const buffer * const b = &fam_dir->name;
size_t blen = buffer_clen(b);
if (blen > len && b->ptr[len] == '/' && 0 == memcmp(b->ptr, name, len))
fam_dir_invalidate_node(fam_dir);
}
/* declarations */
static void stat_cache_delete_tree(const char *name, uint32_t len);
static void stat_cache_invalidate_dir_tree(const char *name, size_t len);
static void stat_cache_handle_fdevent_fn(stat_cache_fam * const scf, fam_dir_entry * const fam_dir, const char * const fn, const uint32_t fnlen, int code);
static void stat_cache_handle_fdevent_in(stat_cache_fam *scf)
{
#ifdef HAVE_SYS_INOTIFY_H
/*(inotify pads in->len to align struct following in->name[])*/
char buf[4096]
__attribute__ ((__aligned__(__alignof__(struct inotify_event))));
int rd;
do {
rd = (int)read(scf->fd, buf, sizeof(buf));
if (rd <= 0) {
if (-1 == rd && errno != EINTR && errno != EAGAIN) {
log_perror(scf->errh, __FILE__, __LINE__, "inotify error");
/* TODO: could flush cache, close scf->fd, and re-open inotify*/
}
break;
}
for (int i = 0; i < rd; ) {
struct inotify_event * const in =
(struct inotify_event *)((uintptr_t)buf + i);
uint32_t len = in->len;
if (len > sizeof(buf)) break; /*(should not happen)*/
i += sizeof(struct inotify_event) + len;
if (i > rd) break; /*(should not happen (partial record))*/
if (in->mask & IN_CREATE)
continue; /*(see comment below for FAMCreated)*/
if (in->mask & IN_Q_OVERFLOW) {
log_error(scf->errh, __FILE__, __LINE__,
"inotify queue overflow");
continue;
}
/* ignore events which may have been pending for
* paths recently cancelled via FAMCancelMonitor() */
scf->wds = splaytree_splay(scf->wds, in->wd);
if (!scf->wds || scf->wds->key != in->wd)
continue;
fam_dir_entry *fam_dir = scf->wds->data;
if (NULL == fam_dir) /*(should not happen)*/
continue;
if (fam_dir->req != in->wd) /*(should not happen)*/
continue;
/*(specific to use here in stat_cache.c)*/
int code = 0;
if (in->mask & (IN_ATTRIB | IN_MODIFY))
code = FAMChanged;
else if (in->mask & (IN_DELETE | IN_DELETE_SELF | IN_UNMOUNT))
code = FAMDeleted;
else if (in->mask & (IN_MOVE_SELF | IN_MOVED_FROM))
code = FAMMoved;
if (len) {
do { --len; } while (len && in->name[len-1] == '\0');
}
stat_cache_handle_fdevent_fn(scf, fam_dir, in->name, len, code);
}
} while (rd + sizeof(struct inotify_event) + NAME_MAX + 1 > sizeof(buf));
#elif defined HAVE_SYS_EVENT_H && defined HAVE_KQUEUE
struct kevent kevl[256];
struct timespec t0 = { 0, 0 };
int n;
do {
n = kevent(scf->fd, NULL, 0, kevl, sizeof(kevl)/sizeof(*kevl), &t0);
if (n <= 0) break;
for (int i = 0; i < n; ++i) {
const struct kevent * const kev = kevl+i;
/* ignore events which may have been pending for
* paths recently cancelled via FAMCancelMonitor() */
int ndx = (int)(intptr_t)kev->udata;
scf->dirs = splaytree_splay(scf->dirs, ndx);
if (!scf->dirs || scf->dirs->key != ndx)
continue;
fam_dir_entry *fam_dir = scf->dirs->data;
if (fam_dir->req != (int)kev->ident)
continue;
/*(specific to use here in stat_cache.c)*/
/* note: stat_cache only monitors on directories,
* so events here are only on directories
* note: changes are treated as FAMDeleted since
* it is unknown which file in dir was changed
* This is not efficient, but this stat_cache mechanism also
* should not be used on frequently modified directories. */
int code = 0;
if (kev->fflags & (NOTE_WRITE|NOTE_ATTRIB|NOTE_EXTEND|NOTE_LINK))
code = FAMDeleted; /*(not FAMChanged; see comment above)*/
else if (kev->fflags & (NOTE_DELETE|NOTE_REVOKE))
code = FAMDeleted;
else if (kev->fflags & NOTE_RENAME)
code = FAMMoved;
if (kev->flags & EV_ERROR) /*(not expected; treat as FAMDeleted)*/
code = FAMDeleted;
stat_cache_handle_fdevent_fn(scf, fam_dir, NULL, 0, code);
}
} while (n == sizeof(kevl)/sizeof(*kevl));
#else
for (int i = 0, ndx; i || (i = FAMPending(&scf->fam)) > 0; --i) {
FAMEvent fe;
if (FAMNextEvent(&scf->fam, &fe) < 0) break;
/* ignore events which may have been pending for
* paths recently cancelled via FAMCancelMonitor() */
ndx = (int)(intptr_t)fe.userdata;
scf->dirs = splaytree_splay(scf->dirs, ndx);
if (!scf->dirs || scf->dirs->key != ndx) {
continue;
}
fam_dir_entry *fam_dir = scf->dirs->data;
if (FAMREQUEST_GETREQNUM(&fam_dir->req)
!= FAMREQUEST_GETREQNUM(&fe.fr)) {
continue;
}
uint32_t fnlen = (fe.code != FAMCreated && fe.filename[0] != '/')
? (uint32_t)strlen(fe.filename)
: 0;
stat_cache_handle_fdevent_fn(scf, fam_dir, fe.filename, fnlen, fe.code);
}
#endif
}
static void stat_cache_handle_fdevent_fn(stat_cache_fam * const scf, fam_dir_entry *fam_dir, const char * const fn, const uint32_t fnlen, int code)
{
if (fnlen) {
buffer * const n = &fam_dir->name;
fam_dir_entry *fam_link;
uint32_t len;
switch (code) {
case FAMCreated:
/* file created in monitored dir modifies dir and
* we should get a separate FAMChanged event for dir.
* Therefore, ignore file FAMCreated event here.
* Also, if FAMNoExists() is used, might get spurious
* FAMCreated events as changes are made e.g. in monitored
* sub-sub-sub dirs and the library discovers new (already
* existing) dir entries */
return;
case FAMChanged:
/* file changed in monitored dir does not modify dir */
case FAMDeleted:
case FAMMoved:
/* file deleted or moved in monitored dir modifies dir,
* but FAM provides separate notification for that */
/* temporarily append filename to dir in fam_dir->name to
* construct path, then delete stat_cache entry (if any)*/
len = buffer_clen(n);
buffer_append_path_len(n, fn, fnlen);
/* (alternatively, could chose to stat() and update)*/
stat_cache_invalidate_entry(BUF_PTR_LEN(n));
fam_link = /*(check if might be symlink to monitored dir)*/
stat_cache_sptree_find(&scf->dirs, BUF_PTR_LEN(n));
if (fam_link && !buffer_is_equal(&fam_link->name, n))
fam_link = NULL;
buffer_truncate(n, len);
if (fam_link) {
/* replaced symlink changes containing dir */
stat_cache_invalidate_entry(n->ptr, len);
/* handle symlink to dir as deleted dir below */
code = FAMDeleted;
fam_dir = fam_link;
break;
}
return;
default:
return;
}
}
switch(code) {
case FAMChanged:
stat_cache_invalidate_entry(BUF_PTR_LEN(&fam_dir->name));
break;
case FAMDeleted:
case FAMMoved:
stat_cache_delete_tree(BUF_PTR_LEN(&fam_dir->name));
fam_dir_invalidate_node(fam_dir);
if (scf->dirs)
fam_dir_invalidate_tree(scf->dirs,
BUF_PTR_LEN(&fam_dir->name));
fam_dir_periodic_cleanup();
break;
default:
break;
}
}
static handler_t stat_cache_handle_fdevent(void *ctx, int revent)
{
stat_cache_fam * const scf = ctx; /* sc.scf */
if (revent & FDEVENT_IN) {
stat_cache_handle_fdevent_in(scf);
}
if (revent & (FDEVENT_HUP|FDEVENT_RDHUP)) {
/* fam closed the connection */
log_error(scf->errh, __FILE__, __LINE__,
"FAM connection closed; disabling stat_cache.");
/* (although effectively STAT_CACHE_ENGINE_NONE,
* do not change here so that periodic jobs clean up memory)*/
/*sc.stat_cache_engine = STAT_CACHE_ENGINE_NONE; */
fdevent_fdnode_event_del(scf->ev, scf->fdn);
fdevent_unregister(scf->ev, scf->fd);
scf->fdn = NULL;
FAMClose(&scf->fam);
scf->fd = -1;
}
return HANDLER_GO_ON;
}
static stat_cache_fam * stat_cache_init_fam(fdevents *ev, log_error_st *errh) {
stat_cache_fam *scf = calloc(1, sizeof(*scf));
force_assert(scf);
scf->fd = -1;
scf->ev = ev;
scf->errh = errh;
#ifdef HAVE_SYS_INOTIFY_H
scf->fd = inotify_init1(IN_NONBLOCK|IN_CLOEXEC);
if (scf->fd < 0) {
log_perror(errh, __FILE__, __LINE__, "inotify_init1()");
free(scf);
return NULL;
}
#elif defined HAVE_SYS_EVENT_H && defined HAVE_KQUEUE
#ifdef __NetBSD__
scf->fd = kqueue1(O_NONBLOCK|O_CLOEXEC|O_NOSIGPIPE);
#else
scf->fd = kqueue();
if (scf->fd >= 0) fdevent_setfd_cloexec(scf->fd);
#endif
if (scf->fd < 0) {
log_perror(errh, __FILE__, __LINE__, "kqueue()");
free(scf);
return NULL;
}
#else
/* setup FAM */
if (0 != FAMOpen2(&scf->fam, "lighttpd")) {
log_error(errh, __FILE__, __LINE__,
"could not open a fam connection, dying.");
free(scf);
return NULL;
}
#ifdef HAVE_FAMNOEXISTS
#ifdef LIGHTTPD_STATIC
FAMNoExists(&scf->fam);
#else
int (*FAMNoExists_fn)(FAMConnection *);
FAMNoExists_fn =
(int (*)(FAMConnection *))(intptr_t)dlsym(RTLD_DEFAULT,"FAMNoExists");
if (FAMNoExists_fn) FAMNoExists_fn(&scf->fam);
#endif
#endif
scf->fd = FAMCONNECTION_GETFD(&scf->fam);
fdevent_setfd_cloexec(scf->fd);
#endif
scf->fdn = fdevent_register(scf->ev, scf->fd, stat_cache_handle_fdevent, scf);
fdevent_fdnode_event_set(scf->ev, scf->fdn, FDEVENT_IN | FDEVENT_RDHUP);
return scf;
}
static void stat_cache_free_fam(stat_cache_fam *scf) {
if (NULL == scf) return;
#ifdef HAVE_SYS_INOTIFY_H
while (scf->wds) {
splay_tree *node = scf->wds;
scf->wds = splaytree_delete(scf->wds, node->key);
}
#elif defined HAVE_SYS_EVENT_H && defined HAVE_KQUEUE
/*(quicker cleanup to close kqueue() before cancel per entry)*/
close(scf->fd);
scf->fd = -1;
#endif
while (scf->dirs) {
/*(skip entry invalidation and FAMCancelMonitor())*/
splay_tree *node = scf->dirs;
fam_dir_entry_free((fam_dir_entry *)node->data);
scf->dirs = splaytree_delete(scf->dirs, node->key);
}
if (-1 != scf->fd) {
/*scf->fdn already cleaned up in fdevent_free()*/
FAMClose(&scf->fam);
/*scf->fd = -1;*/
}
free(scf);
}
static fam_dir_entry * fam_dir_monitor(stat_cache_fam *scf, char *fn, uint32_t dirlen, struct stat *st)
{
if (NULL == scf->fdn) return NULL; /* FAM connection closed; do nothing */
const int fn_is_dir = S_ISDIR(st->st_mode);
/*force_assert(0 != dirlen);*/
/*force_assert(fn[0] == '/');*/
/* consistency: ensure fn does not end in '/' unless root "/"
* FAM events will not end in '/', so easier to match this way */
if (fn[dirlen-1] == '/') --dirlen;
if (0 == dirlen) dirlen = 1; /* root dir ("/") */
/* Note: paths are expected to be normalized before calling stat_cache,
* e.g. without repeated '/' */
if (!fn_is_dir) {
while (fn[--dirlen] != '/') ;
if (0 == dirlen) dirlen = 1; /*(should not happen for file)*/
}
int dir_ndx = splaytree_djbhash(fn, dirlen);
fam_dir_entry *fam_dir = NULL;
scf->dirs = splaytree_splay(scf->dirs, dir_ndx);
if (NULL != scf->dirs && scf->dirs->key == dir_ndx) {
fam_dir = scf->dirs->data;
if (!buffer_eq_slen(&fam_dir->name, fn, dirlen)) {
/* hash collision; preserve existing
* do not monitor new to avoid cache thrashing */
return NULL;
}
/* directory already registered */
}
const unix_time64_t cur_ts = log_monotonic_secs;
struct stat lst;
int ck_dir = fn_is_dir;
if (!fn_is_dir && (NULL==fam_dir || cur_ts - fam_dir->stat_ts >= 16)) {
ck_dir = 1;
/*(temporarily modify fn)*/
fn[dirlen] = '\0';
if (0 != lstat(fn, &lst)) {
fn[dirlen] = '/';
return NULL;
}
if (!S_ISLNK(lst.st_mode)) {
st = &lst;
}
else if (0 != stat(fn, st)) { /*st passed in now is stat() of dir*/
fn[dirlen] = '/';
return NULL;
}
fn[dirlen] = '/';
}
int ck_lnk = (NULL == fam_dir);
if (ck_dir && NULL != fam_dir) {
/* check stat() matches device and inode, just in case an external event
* not being monitored occurs (e.g. rename of unmonitored parent dir)*/
if (st->st_dev != fam_dir->st_dev || st->st_ino != fam_dir->st_ino) {
ck_lnk = 1;
/*(modifies scf->dirs but no need to re-splay for dir_ndx since
* fam_dir is not NULL and so splaytree_insert not called below)*/
if (scf->dirs) fam_dir_invalidate_tree(scf->dirs, fn, dirlen);
if (!fn_is_dir) /*(if dir, caller is updating stat_cache_entry)*/
stat_cache_update_entry(fn, dirlen, st, NULL);
/*(must not delete tree since caller is holding a valid node)*/
stat_cache_invalidate_dir_tree(fn, dirlen);
#ifdef HAVE_SYS_INOTIFY_H
scf->wds = splaytree_delete(scf->wds, fam_dir->req);
#endif
if (0 != FAMCancelMonitor(&scf->fam, &fam_dir->req)
|| 0 != FAMMonitorDirectory(&scf->fam, fam_dir->name.ptr,
&fam_dir->req,
(void *)(intptr_t)dir_ndx)) {
fam_dir->stat_ts = 0; /* invalidate */
return NULL;
}
fam_dir->st_dev = st->st_dev;
fam_dir->st_ino = st->st_ino;
#ifdef HAVE_SYS_INOTIFY_H
scf->wds = splaytree_insert(scf->wds, fam_dir->req, fam_dir);
#endif
}
fam_dir->stat_ts = cur_ts;
}
if (NULL == fam_dir) {
fam_dir = fam_dir_entry_init(fn, dirlen);
if (0 != FAMMonitorDirectory(&scf->fam,fam_dir->name.ptr,&fam_dir->req,
(void *)(intptr_t)dir_ndx)) {
#if defined(HAVE_SYS_INOTIFY_H) \
|| (defined HAVE_SYS_EVENT_H && defined HAVE_KQUEUE)
log_perror(scf->errh, __FILE__, __LINE__,
"monitoring dir failed: %s file: %s",
fam_dir->name.ptr, fn);
#else
log_error(scf->errh, __FILE__, __LINE__,
"monitoring dir failed: %s file: %s %s",
fam_dir->name.ptr, fn, FamErrlist[FAMErrno]);
#endif
fam_dir_entry_free(fam_dir);
return NULL;
}
scf->dirs = splaytree_insert(scf->dirs, dir_ndx, fam_dir);
#ifdef HAVE_SYS_INOTIFY_H
scf->wds = splaytree_insert(scf->wds, fam_dir->req, fam_dir);
#endif
fam_dir->stat_ts= cur_ts;
fam_dir->st_dev = st->st_dev;
fam_dir->st_ino = st->st_ino;
}
if (ck_lnk) {
if (fn_is_dir) {
/*(temporarily modify fn)*/
char e = fn[dirlen];
fn[dirlen] = '\0';
if (0 != lstat(fn, &lst)) {
fn[dirlen] = e;
return NULL;
}
fn[dirlen] = e;
}
if (fam_dir->fam_parent) {
--fam_dir->fam_parent->refcnt;
fam_dir->fam_parent = NULL;
}
if (S_ISLNK(lst.st_mode)) {
fam_dir->fam_parent = fam_dir_monitor(scf, fn, dirlen, &lst);
}
}
++fam_dir->refcnt;
return fam_dir;
}
#endif
__attribute_malloc__
__attribute_returns_nonnull__
static stat_cache_entry * stat_cache_entry_init(void) {
stat_cache_entry *sce = calloc(1, sizeof(*sce));
force_assert(NULL != sce);
sce->fd = -1;
sce->refcnt = 1;
return sce;
}
static void stat_cache_entry_free(void *data) {
stat_cache_entry *sce = data;
if (!sce) return;
if (--sce->refcnt) return;
#ifdef HAVE_FAM_H
/*(decrement refcnt only;
* defer cancelling FAM monitor on dir even if refcnt reaches zero)*/
if (sce->fam_dir) --((fam_dir_entry *)sce->fam_dir)->refcnt;
#endif
free(sce->name.ptr);
free(sce->etag.ptr);
if (sce->content_type.size) free(sce->content_type.ptr);
if (sce->fd >= 0) close(sce->fd);
free(sce);
}
void stat_cache_entry_refchg(void *data, int mod) {
/*(expect mod == -1 or mod == 1)*/
stat_cache_entry * const sce = data;
if (mod < 0 && 1 == sce->refcnt)
stat_cache_entry_free(data);
else
sce->refcnt += mod;
}
#if defined(HAVE_XATTR) || defined(HAVE_EXTATTR)
static const char *attrname = "Content-Type";
static char attrval[128];
static buffer attrb = { attrval, 0, 0 };
static int stat_cache_attr_get(const char *name) {
#if defined(HAVE_XATTR)
#if defined(HAVE_SYS_XATTR_H)
ssize_t attrlen;
if (0 < (attrlen = getxattr(name, attrname,
attrval, sizeof(attrval)-1)))
#else
int attrlen = sizeof(attrval)-1;
if (0 == attr_get(name, attrname, attrval, &attrlen, 0))
#endif
#elif defined(HAVE_EXTATTR)
ssize_t attrlen;
if (0 < (attrlen = extattr_get_file(name, EXTATTR_NAMESPACE_USER, attrname,
attrval, sizeof(attrval)-1)))
#endif
{
attrval[attrlen] = '\0';
attrb.used = (uint32_t)(attrlen + 1);
return 1;
}
return 0;
}
#endif
int stat_cache_init(fdevents *ev, log_error_st *errh) {
#ifdef HAVE_FAM_H
if (sc.stat_cache_engine == STAT_CACHE_ENGINE_FAM) {
sc.scf = stat_cache_init_fam(ev, errh);
if (NULL == sc.scf) return 0;
}
#else
UNUSED(ev);
UNUSED(errh);
#endif
return 1;
}
void stat_cache_free(void) {
splay_tree *sptree = sc.files;
while (sptree) {
stat_cache_entry_free(sptree->data);
sptree = splaytree_delete(sptree, sptree->key);
}
sc.files = NULL;
#ifdef HAVE_FAM_H
stat_cache_free_fam(sc.scf);
sc.scf = NULL;
#endif
#if defined(HAVE_XATTR) || defined(HAVE_EXTATTR)
attrname = "Content-Type";
#endif
sc.stat_cache_engine = STAT_CACHE_ENGINE_SIMPLE; /*(default)*/
}
void stat_cache_xattrname (const char *name) {
#if defined(HAVE_XATTR) || defined(HAVE_EXTATTR)
attrname = name;
#else
UNUSED(name);
#endif
}
int stat_cache_choose_engine (const buffer *stat_cache_string, log_error_st *errh) {
if (buffer_is_blank(stat_cache_string))
sc.stat_cache_engine = STAT_CACHE_ENGINE_SIMPLE;
else if (buffer_eq_slen(stat_cache_string, CONST_STR_LEN("simple")))
sc.stat_cache_engine = STAT_CACHE_ENGINE_SIMPLE;
#ifdef HAVE_SYS_INOTIFY_H
else if (buffer_eq_slen(stat_cache_string, CONST_STR_LEN("inotify")))
sc.stat_cache_engine = STAT_CACHE_ENGINE_INOTIFY;
/*(STAT_CACHE_ENGINE_FAM == STAT_CACHE_ENGINE_INOTIFY)*/
#elif defined HAVE_SYS_EVENT_H && defined HAVE_KQUEUE
else if (buffer_eq_slen(stat_cache_string, CONST_STR_LEN("kqueue")))
sc.stat_cache_engine = STAT_CACHE_ENGINE_KQUEUE;
/*(STAT_CACHE_ENGINE_FAM == STAT_CACHE_ENGINE_KQUEUE)*/
#endif
#ifdef HAVE_FAM_H
else if (buffer_eq_slen(stat_cache_string, CONST_STR_LEN("fam")))
sc.stat_cache_engine = STAT_CACHE_ENGINE_FAM;
#endif
else if (buffer_eq_slen(stat_cache_string, CONST_STR_LEN("disable"))
|| buffer_eq_slen(stat_cache_string, CONST_STR_LEN("none")))
sc.stat_cache_engine = STAT_CACHE_ENGINE_NONE;
else {
log_error(errh, __FILE__, __LINE__,
"server.stat-cache-engine can be one of \"disable\", \"simple\","
#ifdef HAVE_SYS_INOTIFY_H
" \"inotify\","
#elif defined HAVE_SYS_EVENT_H && defined HAVE_KQUEUE
" \"kqueue\","
#endif
#ifdef HAVE_FAM_H
" \"fam\","
#endif
" but not: %s", stat_cache_string->ptr);
return -1;
}
return 0;
}
const buffer * stat_cache_mimetype_by_ext(const array * const mimetypes, const char * const name, const uint32_t nlen)
{
const char * const end = name + nlen; /*(end of string)*/
const uint32_t used = mimetypes->used;
if (used < 16) {
for (uint32_t i = 0; i < used; ++i) {
/* suffix match */
const data_string *ds = (data_string *)mimetypes->data[i];
const size_t klen = buffer_clen(&ds->key);
if (klen <= nlen && buffer_eq_icase_ssn(end-klen, ds->key.ptr, klen))
return &ds->value;
}
}
else {
const char *s;
const data_string *ds;
if (nlen) {
for (s = end-1; s != name && *s != '/'; --s) ; /*(like memrchr())*/
if (*s == '/') ++s;
}
else {
s = name;
}
/* search for basename, then longest .ext2.ext1, then .ext1, then "" */
ds = (const data_string *)array_get_element_klen(mimetypes, s, end - s);
if (NULL != ds) return &ds->value;
while (++s < end) {
while (*s != '.' && ++s != end) ;
if (s == end) break;
/* search ".ext" then "ext" */
ds = (const data_string *)array_get_element_klen(mimetypes, s, end - s);
if (NULL != ds) return &ds->value;
/* repeat search without leading '.' to handle situation where
* admin configured mimetype.assign keys without leading '.' */
if (++s < end) {
if (*s == '.') { --s; continue; }
ds = (const data_string *)array_get_element_klen(mimetypes, s, end - s);
if (NULL != ds) return &ds->value;
}
}
/* search for ""; catchall */
ds = (const data_string *)array_get_element_klen(mimetypes, CONST_STR_LEN(""));
if (NULL != ds) return &ds->value;
}
return NULL;
}
#if defined(HAVE_XATTR) || defined(HAVE_EXTATTR)
const buffer * stat_cache_mimetype_by_xattr(const char * const name)
{
return stat_cache_attr_get(name) ? &attrb : NULL;
}
const buffer * stat_cache_content_type_get_by_xattr(stat_cache_entry *sce, const array *mimetypes, int use_xattr)
{
/*(invalid caching if user config has multiple, different
* r->conf.mimetypes for same extension (not expected))*/
if (!buffer_is_blank(&sce->content_type)) return &sce->content_type;
if (!S_ISREG(sce->st.st_mode)) return NULL;
/* cache mimetype */
const buffer *mtype =
(use_xattr) ? stat_cache_mimetype_by_xattr(sce->name.ptr) : NULL;
if (NULL == mtype)
mtype = stat_cache_mimetype_by_ext(mimetypes, BUF_PTR_LEN(&sce->name));
if (NULL != mtype) {
if (sce->content_type.size) {
buffer_copy_buffer(&sce->content_type, mtype);
}
else if (mtype == &attrb) {
sce->content_type.ptr = NULL;
buffer_copy_buffer(&sce->content_type, mtype);
}
else {
/*(copy pointers from mimetypes array; avoid allocation)*/
sce->content_type.ptr = mtype->ptr;
sce->content_type.used = mtype->used;
/*(leave sce->content_type.size = 0 to flag not-allocated)*/
}
}
else
buffer_clear(&sce->content_type);
return &sce->content_type;
}
#else
const buffer * stat_cache_content_type_get_by_ext(stat_cache_entry *sce, const array *mimetypes)
{
/*(invalid caching if user config has multiple, different
* r->conf.mimetypes for same extension (not expected))*/
if (!buffer_is_blank(&sce->content_type)) return &sce->content_type;
if (!S_ISREG(sce->st.st_mode)) return NULL;
/* cache mimetype */
const buffer * const mtype =
stat_cache_mimetype_by_ext(mimetypes, BUF_PTR_LEN(&sce->name));
if (NULL != mtype) {
/*(copy pointers from mimetypes array; avoid allocation)*/
sce->content_type.ptr = mtype->ptr;
sce->content_type.used = mtype->used;
/*(leave sce->content_type.size = 0 to flag not-allocated)*/
}
else
buffer_clear(&sce->content_type);
return &sce->content_type;
}
#endif
const buffer * stat_cache_etag_get(stat_cache_entry *sce, int flags) {
/*(invalid caching if user cfg has multiple, different r->conf.etag_flags
* for same path (not expected, since etag flags should be by filesystem))*/
if (!buffer_is_blank(&sce->etag)) return &sce->etag;
if (S_ISREG(sce->st.st_mode) || S_ISDIR(sce->st.st_mode)) {
if (0 == flags) return NULL;
http_etag_create(&sce->etag, &sce->st, flags);
return &sce->etag;
}
return NULL;
}
__attribute_pure__
static int stat_cache_stat_eq(const struct stat * const sta, const struct stat * const stb) {
return
#ifdef st_mtime /* use high-precision timestamp if available */
#if defined(__APPLE__) && defined(__MACH__)
sta->st_mtimespec.tv_nsec == stb->st_mtimespec.tv_nsec
#else
sta->st_mtim.tv_nsec == stb->st_mtim.tv_nsec
#endif
#else
1
#endif
&& sta->st_mtime == stb->st_mtime
&& sta->st_size == stb->st_size
&& sta->st_ino == stb->st_ino
&& sta->st_dev == stb->st_dev;
}
void stat_cache_update_entry(const char *name, uint32_t len,
struct stat *st, buffer *etagb)
{
if (sc.stat_cache_engine == STAT_CACHE_ENGINE_NONE) return;
force_assert(0 != len);
if (name[len-1] == '/') { if (0 == --len) len = 1; }
splay_tree **sptree = &sc.files;
stat_cache_entry *sce =
stat_cache_sptree_find(sptree, name, len);
if (sce && buffer_is_equal_string(&sce->name, name, len)) {
if (!stat_cache_stat_eq(&sce->st, st)) {
/* etagb might be NULL to clear etag (invalidate) */
buffer_clear(&sce->etag);
if (etagb)
buffer_copy_string_len(&sce->etag, BUF_PTR_LEN(etagb));
#if defined(HAVE_XATTR) || defined(HAVE_EXTATTR)
buffer_clear(&sce->content_type);
#endif
if (sce->fd >= 0) {
if (1 == sce->refcnt) {
close(sce->fd);
sce->fd = -1;
}
else {
--sce->refcnt; /* stat_cache_entry_free(sce); */
(*sptree)->data = sce = stat_cache_entry_init();
buffer_copy_string_len(&sce->name, name, len);
}
}
sce->st = *st;
}
sce->stat_ts = log_monotonic_secs;
}
}
void stat_cache_delete_entry(const char *name, uint32_t len)
{
if (sc.stat_cache_engine == STAT_CACHE_ENGINE_NONE) return;
force_assert(0 != len);
if (name[len-1] == '/') { if (0 == --len) len = 1; }
splay_tree **sptree = &sc.files;
stat_cache_entry *sce = stat_cache_sptree_find(sptree, name, len);
if (sce && buffer_is_equal_string(&sce->name, name, len)) {
stat_cache_entry_free(sce);
*sptree = splaytree_delete(*sptree, (*sptree)->key);
}
}
void stat_cache_invalidate_entry(const char *name, uint32_t len)
{
splay_tree **sptree = &sc.files;
stat_cache_entry *sce = stat_cache_sptree_find(sptree, name, len);
if (sce && buffer_is_equal_string(&sce->name, name, len)) {
sce->stat_ts = 0;
#ifdef HAVE_FAM_H
if (sce->fam_dir != NULL) {
--((fam_dir_entry *)sce->fam_dir)->refcnt;
sce->fam_dir = NULL;
}
#endif
}
}
#ifdef HAVE_FAM_H
static void stat_cache_invalidate_dir_tree_walk(splay_tree *t,
const char *name, size_t len)
{
if (t->left) stat_cache_invalidate_dir_tree_walk(t->left, name, len);
if (t->right) stat_cache_invalidate_dir_tree_walk(t->right, name, len);
const buffer * const b = &((stat_cache_entry *)t->data)->name;
const size_t blen = buffer_clen(b);
if (blen > len && b->ptr[len] == '/' && 0 == memcmp(b->ptr, name, len)) {
stat_cache_entry *sce = t->data;
sce->stat_ts = 0;
if (sce->fam_dir != NULL) {
--((fam_dir_entry *)sce->fam_dir)->refcnt;
sce->fam_dir = NULL;
}
}
}
static void stat_cache_invalidate_dir_tree(const char *name, size_t len)
{
splay_tree * const sptree = sc.files;
if (sptree) stat_cache_invalidate_dir_tree_walk(sptree, name, len);
}
#endif
/*
* walk though splay_tree and collect contents of dir tree.
* remove tagged entries in a second loop
*/
static void stat_cache_tag_dir_tree(splay_tree *t, const char *name, size_t len,
int *keys, int *ndx)
{
if (*ndx == 8192) return; /*(must match num array entries in keys[])*/
if (t->left) stat_cache_tag_dir_tree(t->left, name, len, keys, ndx);
if (t->right) stat_cache_tag_dir_tree(t->right, name, len, keys, ndx);
if (*ndx == 8192) return; /*(must match num array entries in keys[])*/
const buffer * const b = &((stat_cache_entry *)t->data)->name;
const size_t blen = buffer_clen(b);
if (blen > len && b->ptr[len] == '/' && 0 == memcmp(b->ptr, name, len))
keys[(*ndx)++] = t->key;
}
__attribute_noinline__
static void stat_cache_prune_dir_tree(const char *name, size_t len)
{
splay_tree *sptree = sc.files;
int max_ndx, i;
int keys[8192]; /* 32k size on stack */
do {
if (!sptree) break;
max_ndx = 0;
stat_cache_tag_dir_tree(sptree, name, len, keys, &max_ndx);
for (i = 0; i < max_ndx; ++i) {
const int ndx = keys[i];
splay_tree *node = sptree = splaytree_splay(sptree, ndx);
if (node && node->key == ndx) {
stat_cache_entry_free(node->data);
sptree = splaytree_delete(sptree, ndx);
}
}
} while (max_ndx == sizeof(keys)/sizeof(int));
sc.files = sptree;
}
static void stat_cache_delete_tree(const char *name, uint32_t len)
{
stat_cache_delete_entry(name, len);
stat_cache_prune_dir_tree(name, len);
}
void stat_cache_delete_dir(const char *name, uint32_t len)
{
force_assert(0 != len);
if (name[len-1] == '/') { if (0 == --len) len = 1; }
stat_cache_delete_tree(name, len);
#ifdef HAVE_FAM_H
if (sc.stat_cache_engine == STAT_CACHE_ENGINE_FAM) {
splay_tree **sptree = &sc.scf->dirs;
fam_dir_entry *fam_dir = stat_cache_sptree_find(sptree, name, len);
if (fam_dir && buffer_eq_slen(&fam_dir->name, name, len))
fam_dir_invalidate_node(fam_dir);
if (*sptree) fam_dir_invalidate_tree(*sptree, name, len);
fam_dir_periodic_cleanup();
}
#endif
}
/***
*
*
*
* returns:
* - HANDLER_FINISHED on cache-miss (don't forget to reopen the file)
* - HANDLER_ERROR on stat() failed -> see errno for problem
*/
stat_cache_entry * stat_cache_get_entry(const buffer * const name) {
stat_cache_entry *sce = NULL;
/* consistency: ensure lookup name does not end in '/' unless root "/"
* (but use full path given with stat(), even with trailing '/') */
int final_slash = 0;
size_t len = buffer_clen(name);
force_assert(0 != len);
if (name->ptr[len-1] == '/') { final_slash = 1; if (0 == --len) len = 1; }
/* Note: paths are expected to be normalized before calling stat_cache,
* e.g. without repeated '/' */
if (name->ptr[0] != '/') {
errno = EINVAL;
return NULL;
}
/*
* check if the directory for this file has changed
*/
const unix_time64_t cur_ts = log_monotonic_secs;
const int file_ndx = splaytree_djbhash(name->ptr, len);
splay_tree *sptree = sc.files = splaytree_splay(sc.files, file_ndx);
if (sptree && (sptree->key == file_ndx)) {
/* we have seen this file already and
* don't stat() it again in the same second */
sce = sptree->data;
/* check if the name is the same, we might have a collision */
if (buffer_is_equal_string(&sce->name, name->ptr, len)) {
if (sc.stat_cache_engine == STAT_CACHE_ENGINE_SIMPLE) {
if (sce->stat_ts == cur_ts) {
if (final_slash && !S_ISDIR(sce->st.st_mode)) {
errno = ENOTDIR;
return NULL;
}
return sce;
}
}
#ifdef HAVE_FAM_H
else if (sc.stat_cache_engine == STAT_CACHE_ENGINE_FAM
&& sce->fam_dir) { /* entry is in monitored dir */
/* re-stat() periodically, even if monitoring for changes
* (due to limitations in stat_cache.c use of FAM)
* (gaps due to not continually monitoring an entire tree) */
if (cur_ts - sce->stat_ts < 16) {
if (final_slash && !S_ISDIR(sce->st.st_mode)) {
errno = ENOTDIR;
return NULL;
}
return sce;
}
}
#endif
} else {
/* collision, forget about the entry */
sce = NULL;
}
}
struct stat st;
if (-1 == stat(name->ptr, &st)) {
return NULL;
}
if (NULL == sce) {
/* fix broken stat/open for symlinks to reg files with appended slash on freebsd,osx */
if (final_slash && S_ISREG(st.st_mode)) {
errno = ENOTDIR;
return NULL;
}
sce = stat_cache_entry_init();
buffer_copy_string_len(&sce->name, name->ptr, len);
/* already splayed file_ndx */
if (NULL != sptree && sptree->key == file_ndx) {
/* hash collision: replace old entry */
stat_cache_entry_free(sptree->data);
sptree->data = sce;
} else {
/*sptree =*/ sc.files = splaytree_insert(sptree, file_ndx, sce);
}
} else {
buffer_clear(&sce->etag);
#if defined(HAVE_XATTR) || defined(HAVE_EXTATTR)
buffer_clear(&sce->content_type);
#endif
/* close fd if file changed */
if (sce->fd >= 0 && !stat_cache_stat_eq(&sce->st, &st)) {
if (1 == sce->refcnt) {
close(sce->fd);
sce->fd = -1;
}
else {
--sce->refcnt; /* stat_cache_entry_free(sce); */
sptree->data = sce = stat_cache_entry_init();
buffer_copy_string_len(&sce->name, name->ptr, len);
}
}
}
sce->st = st; /*(copy prior to calling fam_dir_monitor())*/
#ifdef HAVE_FAM_H
if (sc.stat_cache_engine == STAT_CACHE_ENGINE_FAM) {
if (sce->fam_dir) --((fam_dir_entry *)sce->fam_dir)->refcnt;
sce->fam_dir =
fam_dir_monitor(sc.scf, name->ptr, len, &st);
#if 0 /*(performed below)*/
if (NULL != sce->fam_dir) {
/*(may have been invalidated by dir change)*/
sce->stat_ts = cur_ts;
}
#endif
}
#endif
sce->stat_ts = cur_ts;
return sce;
}
stat_cache_entry * stat_cache_get_entry_open(const buffer * const name, const int symlinks) {
stat_cache_entry * const sce = stat_cache_get_entry(name);
if (NULL == sce) return NULL;
if (sce->fd >= 0) return sce;
if (sce->st.st_size > 0) {
sce->fd = stat_cache_open_rdonly_fstat(name, &sce->st, symlinks);
buffer_clear(&sce->etag);
}
return sce; /* (note: sce->fd might still be -1 if open() failed) */
}
const stat_cache_st * stat_cache_path_stat (const buffer * const name) {
const stat_cache_entry * const sce = stat_cache_get_entry(name);
return sce ? &sce->st : NULL;
}
int stat_cache_path_isdir(const buffer *name) {
const stat_cache_entry * const sce = stat_cache_get_entry(name);
return (sce && (S_ISDIR(sce->st.st_mode) ? 1 : (errno = ENOTDIR, 0)));
}
int stat_cache_path_contains_symlink(const buffer *name, log_error_st *errh) {
/* caller should check for symlinks only if we should block symlinks. */
/* 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.
* */
#ifdef HAVE_LSTAT
/* we assume "/" can not be symlink,
* so skip the symlink stuff if path is "/" */
size_t len = buffer_clen(name);
force_assert(0 != len);
force_assert(name->ptr[0] == '/');
if (1 == len) return 0;
#ifndef PATH_MAX
#define PATH_MAX 4096
#endif
if (len >= PATH_MAX) return -1;
char buf[PATH_MAX];
memcpy(buf, name->ptr, len);
char *s_cur = buf+len;
do {
*s_cur = '\0';
struct stat st;
if (0 == lstat(buf, &st)) {
if (S_ISLNK(st.st_mode)) return 1;
}
else {
log_perror(errh, __FILE__, __LINE__, "lstat failed for: %s", buf);
return -1;
}
} while ((s_cur = strrchr(buf, '/')) > buf); /*(&buf[0]==buf; NULL < buf)*/
#endif
return 0;
}
int stat_cache_open_rdonly_fstat (const buffer *name, struct stat *st, int symlinks) {
/*(Note: O_NOFOLLOW affects only the final path segment, the target file,
* not any intermediate symlinks along the path)*/
const int fd = fdevent_open_cloexec(name->ptr, symlinks, O_RDONLY, 0);
if (fd >= 0) {
if (0 == fstat(fd, st)) {
return fd;
} else {
const int errnum = errno;
close(fd);
errno = errnum;
}
}
return -1;
}
/**
* remove stat() from cache which haven't been stat()ed for
* more than 2 seconds
*
*
* walk though the stat-cache, collect the ids which are too old
* and remove them in a second loop
*/
static void stat_cache_tag_old_entries(splay_tree * const t, int * const keys, int * const ndx, const time_t max_age, const unix_time64_t cur_ts) {
if (*ndx == 8192) return; /*(must match num array entries in keys[])*/
if (t->left)
stat_cache_tag_old_entries(t->left, keys, ndx, max_age, cur_ts);
if (t->right)
stat_cache_tag_old_entries(t->right, keys, ndx, max_age, cur_ts);
if (*ndx == 8192) return; /*(must match num array entries in keys[])*/
const stat_cache_entry * const sce = t->data;
if (cur_ts - sce->stat_ts > max_age)
keys[(*ndx)++] = t->key;
}
static void stat_cache_periodic_cleanup(const time_t max_age, const unix_time64_t cur_ts) {
splay_tree *sptree = sc.files;
int max_ndx, i;
int keys[8192]; /* 32k size on stack */
do {
if (!sptree) break;
max_ndx = 0;
stat_cache_tag_old_entries(sptree, keys, &max_ndx, max_age, cur_ts);
for (i = 0; i < max_ndx; ++i) {
int ndx = keys[i];
sptree = splaytree_splay(sptree, ndx);
if (sptree && sptree->key == ndx) {
stat_cache_entry_free(sptree->data);
sptree = splaytree_delete(sptree, ndx);
}
}
} while (max_ndx == sizeof(keys)/sizeof(int));
sc.files = sptree;
}
void stat_cache_trigger_cleanup(void) {
time_t max_age = 2;
#ifdef HAVE_FAM_H
if (STAT_CACHE_ENGINE_FAM == sc.stat_cache_engine) {
if (log_monotonic_secs & 0x1F) return;
/* once every 32 seconds (0x1F == 31) */
max_age = 32;
fam_dir_periodic_cleanup();
/* By doing this before stat_cache_periodic_cleanup(),
* entries used within the next max_age secs will remain
* monitored, instead of effectively flushing and
* rebuilding the FAM monitoring every max_age seconds */
}
#endif
stat_cache_periodic_cleanup(max_age, log_monotonic_secs);
}
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