/* Copyright Joyent, Inc. and other Node contributors. All rights reserved.
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal in the Software without restriction, including without limitation the
* rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
* sell copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
* IN THE SOFTWARE.
*/
#include "uv.h"
#include "uv/tree.h"
#include "internal.h"
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <assert.h>
#include <errno.h>
#include <sys/types.h>
#include <unistd.h>
struct watcher_list {
RB_ENTRY(watcher_list) entry;
QUEUE watchers;
int iterating;
char* path;
int wd;
};
struct watcher_root {
struct watcher_list* rbh_root;
};
#define CAST(p) ((struct watcher_root*)(p))
static int compare_watchers(const struct watcher_list* a,
const struct watcher_list* b) {
if (a->wd < b->wd) return -1;
if (a->wd > b->wd) return 1;
return 0;
}
RB_GENERATE_STATIC(watcher_root, watcher_list, entry, compare_watchers)
static void uv__inotify_read(uv_loop_t* loop,
uv__io_t* w,
unsigned int revents);
static void maybe_free_watcher_list(struct watcher_list* w,
uv_loop_t* loop);
static int new_inotify_fd(void) {
int err;
int fd;
fd = uv__inotify_init1(UV__IN_NONBLOCK | UV__IN_CLOEXEC);
if (fd != -1)
return fd;
if (errno != ENOSYS)
return UV__ERR(errno);
fd = uv__inotify_init();
if (fd == -1)
return UV__ERR(errno);
err = uv__cloexec(fd, 1);
if (err == 0)
err = uv__nonblock(fd, 1);
if (err) {
uv__close(fd);
return err;
}
return fd;
}
static int init_inotify(uv_loop_t* loop) {
int err;
if (loop->inotify_fd != -1)
return 0;
err = new_inotify_fd();
if (err < 0)
return err;
loop->inotify_fd = err;
uv__io_init(&loop->inotify_read_watcher, uv__inotify_read, loop->inotify_fd);
uv__io_start(loop, &loop->inotify_read_watcher, POLLIN);
return 0;
}
int uv__inotify_fork(uv_loop_t* loop, void* old_watchers) {
/* Open the inotify_fd, and re-arm all the inotify watchers. */
int err;
struct watcher_list* tmp_watcher_list_iter;
struct watcher_list* watcher_list;
struct watcher_list tmp_watcher_list;
QUEUE queue;
QUEUE* q;
uv_fs_event_t* handle;
char* tmp_path;
if (old_watchers != NULL) {
/* We must restore the old watcher list to be able to close items
* out of it.
*/
loop->inotify_watchers = old_watchers;
QUEUE_INIT(&tmp_watcher_list.watchers);
/* Note that the queue we use is shared with the start and stop()
* functions, making QUEUE_FOREACH unsafe to use. So we use the
* QUEUE_MOVE trick to safely iterate. Also don't free the watcher
* list until we're done iterating. c.f. uv__inotify_read.
*/
RB_FOREACH_SAFE(watcher_list, watcher_root,
CAST(&old_watchers), tmp_watcher_list_iter) {
watcher_list->iterating = 1;
QUEUE_MOVE(&watcher_list->watchers, &queue);
while (!QUEUE_EMPTY(&queue)) {
q = QUEUE_HEAD(&queue);
handle = QUEUE_DATA(q, uv_fs_event_t, watchers);
/* It's critical to keep a copy of path here, because it
* will be set to NULL by stop() and then deallocated by
* maybe_free_watcher_list
*/
tmp_path = uv__strdup(handle->path);
assert(tmp_path != NULL);
QUEUE_REMOVE(q);
QUEUE_INSERT_TAIL(&watcher_list->watchers, q);
uv_fs_event_stop(handle);
QUEUE_INSERT_TAIL(&tmp_watcher_list.watchers, &handle->watchers);
handle->path = tmp_path;
}
watcher_list->iterating = 0;
maybe_free_watcher_list(watcher_list, loop);
}
QUEUE_MOVE(&tmp_watcher_list.watchers, &queue);
while (!QUEUE_EMPTY(&queue)) {
q = QUEUE_HEAD(&queue);
QUEUE_REMOVE(q);
handle = QUEUE_DATA(q, uv_fs_event_t, watchers);
tmp_path = handle->path;
handle->path = NULL;
err = uv_fs_event_start(handle, handle->cb, tmp_path, 0);
uv__free(tmp_path);
if (err)
return err;
}
}
return 0;
}
static struct watcher_list* find_watcher(uv_loop_t* loop, int wd) {
struct watcher_list w;
w.wd = wd;
return RB_FIND(watcher_root, CAST(&loop->inotify_watchers), &w);
}
static void maybe_free_watcher_list(struct watcher_list* w, uv_loop_t* loop) {
/* if the watcher_list->watchers is being iterated over, we can't free it. */
if ((!w->iterating) && QUEUE_EMPTY(&w->watchers)) {
/* No watchers left for this path. Clean up. */
RB_REMOVE(watcher_root, CAST(&loop->inotify_watchers), w);
uv__inotify_rm_watch(loop->inotify_fd, w->wd);
uv__free(w);
}
}
static void uv__inotify_read(uv_loop_t* loop,
uv__io_t* dummy,
unsigned int events) {
const struct uv__inotify_event* e;
struct watcher_list* w;
uv_fs_event_t* h;
QUEUE queue;
QUEUE* q;
const char* path;
ssize_t size;
const char *p;
/* needs to be large enough for sizeof(inotify_event) + strlen(path) */
char buf[4096];
while (1) {
do
size = read(loop->inotify_fd, buf, sizeof(buf));
while (size == -1 && errno == EINTR);
if (size == -1) {
assert(errno == EAGAIN || errno == EWOULDBLOCK);
break;
}
assert(size > 0); /* pre-2.6.21 thing, size=0 == read buffer too small */
/* Now we have one or more inotify_event structs. */
for (p = buf; p < buf + size; p += sizeof(*e) + e->len) {
e = (const struct uv__inotify_event*)p;
events = 0;
if (e->mask & (UV__IN_ATTRIB|UV__IN_MODIFY))
events |= UV_CHANGE;
if (e->mask & ~(UV__IN_ATTRIB|UV__IN_MODIFY))
events |= UV_RENAME;
w = find_watcher(loop, e->wd);
if (w == NULL)
continue; /* Stale event, no watchers left. */
/* inotify does not return the filename when monitoring a single file
* for modifications. Repurpose the filename for API compatibility.
* I'm not convinced this is a good thing, maybe it should go.
*/
path = e->len ? (const char*) (e + 1) : uv__basename_r(w->path);
/* We're about to iterate over the queue and call user's callbacks.
* What can go wrong?
* A callback could call uv_fs_event_stop()
* and the queue can change under our feet.
* So, we use QUEUE_MOVE() trick to safely iterate over the queue.
* And we don't free the watcher_list until we're done iterating.
*
* First,
* tell uv_fs_event_stop() (that could be called from a user's callback)
* not to free watcher_list.
*/
w->iterating = 1;
QUEUE_MOVE(&w->watchers, &queue);
while (!QUEUE_EMPTY(&queue)) {
q = QUEUE_HEAD(&queue);
h = QUEUE_DATA(q, uv_fs_event_t, watchers);
QUEUE_REMOVE(q);
QUEUE_INSERT_TAIL(&w->watchers, q);
h->cb(h, path, events, 0);
}
/* done iterating, time to (maybe) free empty watcher_list */
w->iterating = 0;
maybe_free_watcher_list(w, loop);
}
}
}
int uv_fs_event_init(uv_loop_t* loop, uv_fs_event_t* handle) {
uv__handle_init(loop, (uv_handle_t*)handle, UV_FS_EVENT);
return 0;
}
int uv_fs_event_start(uv_fs_event_t* handle,
uv_fs_event_cb cb,
const char* path,
unsigned int flags) {
struct watcher_list* w;
int events;
int err;
int wd;
if (uv__is_active(handle))
return UV_EINVAL;
err = init_inotify(handle->loop);
if (err)
return err;
events = UV__IN_ATTRIB
| UV__IN_CREATE
| UV__IN_MODIFY
| UV__IN_DELETE
| UV__IN_DELETE_SELF
| UV__IN_MOVE_SELF
| UV__IN_MOVED_FROM
| UV__IN_MOVED_TO;
wd = uv__inotify_add_watch(handle->loop->inotify_fd, path, events);
if (wd == -1)
return UV__ERR(errno);
w = find_watcher(handle->loop, wd);
if (w)
goto no_insert;
w = uv__malloc(sizeof(*w) + strlen(path) + 1);
if (w == NULL)
return UV_ENOMEM;
w->wd = wd;
w->path = strcpy((char*)(w + 1), path);
QUEUE_INIT(&w->watchers);
w->iterating = 0;
RB_INSERT(watcher_root, CAST(&handle->loop->inotify_watchers), w);
no_insert:
uv__handle_start(handle);
QUEUE_INSERT_TAIL(&w->watchers, &handle->watchers);
handle->path = w->path;
handle->cb = cb;
handle->wd = wd;
return 0;
}
int uv_fs_event_stop(uv_fs_event_t* handle) {
struct watcher_list* w;
if (!uv__is_active(handle))
return 0;
w = find_watcher(handle->loop, handle->wd);
assert(w != NULL);
handle->wd = -1;
handle->path = NULL;
uv__handle_stop(handle);
QUEUE_REMOVE(&handle->watchers);
maybe_free_watcher_list(w, handle->loop);
return 0;
}
void uv__fs_event_close(uv_fs_event_t* handle) {
uv_fs_event_stop(handle);
}