linux-inotify.c File Reference

#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/inotify.h>
#include <sys/types.h>
#include <unistd.h>

Go to the source code of this file.

Classes
struct	watcher_list
struct	watcher_root

Macros
#define	CAST(p)   ((struct watcher_root*)(p))

Functions
static int	compare_watchers (const struct watcher_list *a, const struct watcher_list *b)
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	init_inotify (uv_loop_t *loop)
int	uv__inotify_fork (uv_loop_t *loop, void *old_watchers)
static struct watcher_list *	find_watcher (uv_loop_t *loop, int wd)
int	uv_fs_event_init (uv_loop_t *loop, uv_fs_event_t *handle)
int	uv_fs_event_start (uv_fs_event_t *handle, uv_fs_event_cb cb, const char *path, unsigned int flags)
int	uv_fs_event_stop (uv_fs_event_t *handle)
void	uv__fs_event_close (uv_fs_event_t *handle)

Macro Definition Documentation

CAST

#define CAST

(

p

)

((struct watcher_root*)(p))

Definition at line 47 of file linux-inotify.c.

Function Documentation

compare_watchers()

static int compare_watchers ( const struct watcher_list *  a, const struct watcher_list *  b  )

static

Definition at line 50 of file linux-inotify.c.

                                                          {
  if (a->wd < b->wd) return -1;
  if (a->wd > b->wd) return 1;
  return 0;
}

References a, and b.

find_watcher()

static struct watcher_list* find_watcher ( uv_loop_t *  loop, int  wd  )

static

Definition at line 151 of file linux-inotify.c.

                                                                  {
  struct watcher_list w;
  w.wd = wd;
  return RB_FIND(watcher_root, CAST(&loop->inotify_watchers), &w);
}

References CAST, loop, RB_FIND, and w.

Referenced by uv__inotify_read(), uv_fs_event_start(), and uv_fs_event_stop().

init_inotify()

static int init_inotify ( uv_loop_t *  loop )

static

Definition at line 68 of file linux-inotify.c.

                                         {
  int fd;
 
  if (loop->inotify_fd != -1)
    return 0;
 
  fd = inotify_init1(IN_NONBLOCK | IN_CLOEXEC);
  if (fd < 0)
    return UV__ERR(errno);
 
  loop->inotify_fd = fd;
  uv__io_init(&loop->inotify_read_watcher, uv__inotify_read, loop->inotify_fd);
  uv__io_start(loop, &loop->inotify_read_watcher, POLLIN);
 
  return 0;
}

References fd, loop, UV__ERR, uv__inotify_read(), uv__io_init(), and uv__io_start().

Referenced by uv_fs_event_start().

maybe_free_watcher_list()

static void maybe_free_watcher_list ( struct watcher_list *  w, uv_loop_t *  loop  )

static

Definition at line 157 of file linux-inotify.c.

                                                                             {
  /* 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);
    inotify_rm_watch(loop->inotify_fd, w->wd);
    uv__free(w);
  }
}

References CAST, loop, QUEUE_EMPTY, RB_REMOVE, uv__free(), and w.

Referenced by uv__inotify_fork(), uv__inotify_read(), and uv_fs_event_stop().

uv__fs_event_close()

void uv__fs_event_close

(

uv_fs_event_t *

handle

)

Definition at line 325 of file linux-inotify.c.

                                               {
  uv_fs_event_stop(handle);
}

References handle, and uv_fs_event_stop().

uv__inotify_fork()

int uv__inotify_fork	(	uv_loop_t *	loop,
		void *	old_watchers
	)

Definition at line 86 of file linux-inotify.c.

                                                          {
  /* 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;
}

References assert(), CAST, err, handle, loop, maybe_free_watcher_list(), NULL, queue, QUEUE_DATA, QUEUE_EMPTY, QUEUE_HEAD, QUEUE_INIT, QUEUE_INSERT_TAIL, QUEUE_MOVE, QUEUE_REMOVE, RB_FOREACH_SAFE, uv__free(), uv__strdup(), uv_fs_event_start(), and uv_fs_event_stop().

Referenced by uv__io_fork().

uv__inotify_read()

static void uv__inotify_read ( uv_loop_t *  loop, uv__io_t *  w, unsigned int  revents  )

static

Definition at line 167 of file linux-inotify.c.

                                                  {
  const struct 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 inotify_event*) p;
 
      events = 0;
      if (e->mask & (IN_ATTRIB|IN_MODIFY))
        events |= UV_CHANGE;
      if (e->mask & ~(IN_ATTRIB|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);
    }
  }
}

References assert(), e, EAGAIN, EINTR, find_watcher(), h, loop, maybe_free_watcher_list(), NULL, p, path, queue, QUEUE_DATA, QUEUE_EMPTY, QUEUE_HEAD, QUEUE_INSERT_TAIL, QUEUE_MOVE, QUEUE_REMOVE, read(), UV_CHANGE, UV_RENAME, and w.

Referenced by init_inotify().

uv_fs_event_init()

int uv_fs_event_init	(	uv_loop_t *	loop,
		uv_fs_event_t *	handle
	)

Definition at line 243 of file linux-inotify.c.

                                                             {
  uv__handle_init(loop, (uv_handle_t*)handle, UV_FS_EVENT);
  return 0;
}

References handle, loop, and uv__handle_init.

uv_fs_event_start()

int uv_fs_event_start	(	uv_fs_event_t *	handle,
		uv_fs_event_cb	cb,
		const char *	path,
		unsigned int	flags
	)

Definition at line 249 of file linux-inotify.c.

                                          {
  struct watcher_list* w;
  size_t len;
  int events;
  int err;
  int wd;
 
  if (uv__is_active(handle))
    return UV_EINVAL;
 
  err = init_inotify(handle->loop);
  if (err)
    return err;
 
  events = IN_ATTRIB
         | IN_CREATE
         | IN_MODIFY
         | IN_DELETE
         | IN_DELETE_SELF
         | IN_MOVE_SELF
         | IN_MOVED_FROM
         | IN_MOVED_TO;
 
  wd = 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;
 
  len = strlen(path) + 1;
  w = uv__malloc(sizeof(*w) + len);
  if (w == NULL)
    return UV_ENOMEM;
 
  w->wd = wd;
  w->path = memcpy(w + 1, path, len);
  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;
}

References CAST, cb, err, find_watcher(), handle, init_inotify(), len, memcpy(), NULL, path, QUEUE_INIT, QUEUE_INSERT_TAIL, RB_INSERT, UV__ERR, uv__handle_start, uv__is_active, uv__malloc(), and w.

Referenced by uv__inotify_fork().

uv_fs_event_stop()

int uv_fs_event_stop

(

uv_fs_event_t *

handle

)

Definition at line 305 of file linux-inotify.c.

                                            {
  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;
}

References assert(), find_watcher(), handle, maybe_free_watcher_list(), NULL, QUEUE_REMOVE, uv__handle_stop, uv__is_active, and w.

Referenced by uv__fs_event_close(), and uv__inotify_fork().