monitor.h File Reference

Monitor files for changes. More...

#include <stdbool.h>

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Functions
int	mutt_monitor_add (struct Mailbox *m)
	Add a watch for a mailbox. More...
int	mutt_monitor_remove (struct Mailbox *m)
	Remove a watch for a mailbox. More...
int	mutt_monitor_poll (void)
	Check for filesystem changes. More...

Variables
bool	MonitorFilesChanged
	true after a monitored file has changed More...
bool	MonitorContextChanged
	true after the current mailbox has changed More...

Detailed Description

Monitor files for changes.

Authors

• Gero Treuner

Copyright

This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation, either version 2 of the License, or (at your option) any later version.

This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with this program. If not, see http://www.gnu.org/licenses/.

Definition in file monitor.h.

Function Documentation

mutt_monitor_add()

int mutt_monitor_add

(

struct Mailbox *

m

)

Add a watch for a mailbox.

Parameters

m	Mailbox to watch

Return values

0	success: new or already existing monitor
-1	failed: no mailbox, inaccessible file, create monitor/watcher failed

If m is NULL, try to get the current mailbox from the Index.

Definition at line 480 of file monitor.c.

{
  struct MonitorInfo info;
  monitor_info_init(&info);
 
  int rc = 0;
  enum ResolveResult desc = monitor_resolve(&info, m);
  if (desc != RESOLVE_RES_OK_NOTEXISTING)
  {
    if (!m && (desc == RESOLVE_RES_OK_EXISTING))
      MonitorContextDescriptor = info.monitor->desc;
    rc = (desc == RESOLVE_RES_OK_EXISTING) ? 0 : -1;
    goto cleanup;
  }
 
  uint32_t mask = info.is_dir ? INOTIFY_MASK_DIR : INOTIFY_MASK_FILE;
  if (((INotifyFd == -1) && (monitor_init() == -1)) ||
      ((desc = inotify_add_watch(INotifyFd, info.path, mask)) == -1))
  {
    mutt_debug(LL_DEBUG2, "inotify_add_watch failed for '%s', errno=%d %s\n",
               info.path, errno, strerror(errno));
    rc = -1;
    goto cleanup;
  }
 
  mutt_debug(LL_DEBUG3, "inotify_add_watch descriptor=%d for '%s'\n", desc, info.path);
  if (!m)
    MonitorContextDescriptor = desc;
 
  monitor_new(&info, desc);
 
cleanup:
  monitor_info_free(&info);
  return rc;
}

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mutt_monitor_remove()

int mutt_monitor_remove

(

struct Mailbox *

m

)

Remove a watch for a mailbox.

Parameters

m

Mailbox

Return values

0	monitor removed (not shared)
1	monitor not removed (shared)
2	no monitor

If m is NULL, try to get the current mailbox from the Index.

Definition at line 525 of file monitor.c.

{
  struct MonitorInfo info, info2;
  int rc = 0;
 
  monitor_info_init(&info);
  monitor_info_init(&info2);
 
  if (!m)
  {
    MonitorContextDescriptor = -1;
    MonitorContextChanged = false;
  }
 
  if (monitor_resolve(&info, m) != RESOLVE_RES_OK_EXISTING)
  {
    rc = 2;
    goto cleanup;
  }
 
  struct Mailbox *m_cur = get_current_mailbox();
  if (m_cur)
  {
    if (m)
    {
      if ((monitor_resolve(&info2, NULL) == RESOLVE_RES_OK_EXISTING) &&
          (info.st_ino == info2.st_ino) && (info.st_dev == info2.st_dev))
      {
        rc = 1;
        goto cleanup;
      }
    }
    else
    {
      if (mailbox_find(m_cur->realpath))
      {
        rc = 1;
        goto cleanup;
      }
    }
  }
 
  inotify_rm_watch(info.monitor->desc, INotifyFd);
  mutt_debug(LL_DEBUG3, "inotify_rm_watch for '%s' descriptor=%d\n", info.path,
             info.monitor->desc);
 
  monitor_delete(info.monitor);
  monitor_check_free();
 
cleanup:
  monitor_info_free(&info);
  monitor_info_free(&info2);
  return rc;
}

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mutt_monitor_poll()

int mutt_monitor_poll

(

void

)

Check for filesystem changes.

Return values

-3	unknown/unexpected events: poll timeout / fds not handled by us
-2	monitor detected changes, no STDIN input
-1	error (see errno)
0	(1) input ready from STDIN, or (2) monitoring inactive -> no poll()

Wait for I/O ready file descriptors or signals.

MonitorFilesChanged also reflects changes to monitored files.

Only STDIN and INotify file handles currently expected/supported. More would ask for common infrastructure (sockets?).

Definition at line 398 of file monitor.c.

{
  int rc = 0;
  char buf[EVENT_BUFLEN] __attribute__((aligned(__alignof__(struct inotify_event))));
 
  MonitorFilesChanged = false;
 
  if (INotifyFd != -1)
  {
    int fds = poll(PollFds, PollFdsCount, MuttGetchTimeout);
 
    if (fds == -1)
    {
      rc = -1;
      if (errno != EINTR)
      {
        mutt_debug(LL_DEBUG2, "poll() failed, errno=%d %s\n", errno, strerror(errno));
      }
    }
    else
    {
      bool input_ready = false;
      for (int i = 0; fds && (i < PollFdsCount); i++)
      {
        if (PollFds[i].revents)
        {
          fds--;
          if (PollFds[i].fd == 0)
          {
            input_ready = true;
          }
          else if (PollFds[i].fd == INotifyFd)
          {
            MonitorFilesChanged = true;
            mutt_debug(LL_DEBUG3, "file change(s) detected\n");
            char *ptr = buf;
            const struct inotify_event *event = NULL;
 
            while (true)
            {
              int len = read(INotifyFd, buf, sizeof(buf));
              if (len == -1)
              {
                if (errno != EAGAIN)
                {
                  mutt_debug(LL_DEBUG2, "read inotify events failed, errno=%d %s\n",
                             errno, strerror(errno));
                }
                break;
              }
 
              while (ptr < (buf + len))
              {
                event = (const struct inotify_event *) ptr;
                mutt_debug(LL_DEBUG3, "+ detail: descriptor=%d mask=0x%x\n",
                           event->wd, event->mask);
                if (event->mask & IN_IGNORED)
                  monitor_handle_ignore(event->wd);
                else if (event->wd == MonitorContextDescriptor)
                  MonitorContextChanged = true;
                ptr += sizeof(struct inotify_event) + event->len;
              }
            }
          }
        }
      }
      if (!input_ready)
        rc = MonitorFilesChanged ? -2 : -3;
    }
  }
 
  return rc;
}

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Variable Documentation

MonitorFilesChanged

bool MonitorFilesChanged

extern

true after a monitored file has changed

Definition at line 49 of file monitor.c.

MonitorContextChanged

bool MonitorContextChanged

extern

true after the current mailbox has changed

Definition at line 50 of file monitor.c.