diff options
author | Colin Walters <walters@verbum.org> | 2010-01-28 16:26:39 -0500 |
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committer | Colin Walters <walters@verbum.org> | 2010-02-01 16:22:56 -0500 |
commit | 8a9880ffd2b81df38bb0e3492bda7a9636ac0280 (patch) | |
tree | 0e81525a5db40a606a2171ee7880e4a4e0c6a765 /bus/dir-watch-kqueue.c | |
parent | 0705eb5c869c2f78c57d9c805e1023e8b26b1a06 (diff) | |
download | dbus-8a9880ffd2b81df38bb0e3492bda7a9636ac0280.tar.gz |
Clean up inotify watch handling
Substantially based on a patch by Matthias Clasen <mclasen@redhat.com>
kqueue implementation by Joe Marcus Clarke <marcus@freebsd.org>
Previously, when we detected a configuration change (which included
the set of config directories to monitor for changes), we would
simply drop all watches, then readd them.
The problem with this is that it introduced a race condition where
we might not be watching one of the config directories for changes.
Rather than dropping and readding, change the OS-dependent monitoring
API to simply take a new set of directories to monitor. Implicit
in this is that the OS-specific layer needs to keep track of the
previously monitored set.
Diffstat (limited to 'bus/dir-watch-kqueue.c')
-rw-r--r-- | bus/dir-watch-kqueue.c | 136 |
1 files changed, 100 insertions, 36 deletions
diff --git a/bus/dir-watch-kqueue.c b/bus/dir-watch-kqueue.c index 16741dd0..7c18a3c9 100644 --- a/bus/dir-watch-kqueue.c +++ b/bus/dir-watch-kqueue.c @@ -37,12 +37,14 @@ #include <dbus/dbus-watch.h> #include <dbus/dbus-internals.h> +#include <dbus/dbus-list.h> #include "dir-watch.h" #define MAX_DIRS_TO_WATCH 128 static int kq = -1; static int fds[MAX_DIRS_TO_WATCH]; +static char *dirs[MAX_DIRS_TO_WATCH]; static int num_fds = 0; static DBusWatch *watch = NULL; static DBusLoop *loop = NULL; @@ -90,13 +92,10 @@ _handle_kqueue_watch (DBusWatch *watch, unsigned int flags, void *data) return TRUE; } -void -bus_watch_directory (const char *dir, BusContext *context) +static int +_init_kqueue (BusContext *context) { - int fd; - struct kevent ev; - - _dbus_assert (dir != NULL); + int ret = 0; if (kq < 0) { @@ -133,49 +132,114 @@ bus_watch_directory (const char *dir, BusContext *context) } } - if (num_fds >= MAX_DIRS_TO_WATCH ) + ret = 1; + +out: + return ret; +} + +void +bus_set_watched_dir (BusContext *context, DBusList **directories) +{ + int new_fds[MAX_DIRS_TO_WATCH]; + char *new_dirs[MAX_DIRS_TO_WATCH]; + DBusList *link; + int i, f, fd; + + if (!_init_kqueue (context)) + goto out; + + for (i = 0; i < MAX_DIRS_TO_WATCH; i++) { { - _dbus_warn ("Cannot watch config directory '%s'. Already watching %d directories\n", dir, MAX_DIRS_TO_WATCH); - goto out; + new_fds[i] = -1; + new_dirs[i] = NULL; } - fd = open (dir, O_RDONLY); - if (fd < 0) + i = 0; + link = _dbus_list_get_first_link (directories); + while (link != NULL) { - _dbus_warn ("Cannot open directory '%s'; error '%s'\n", dir, _dbus_strerror (errno)); - goto out; + new_dirs[i++] = (char *)link->data; + link = _dbus_list_get_next_link (directories, link); } - EV_SET (&ev, fd, EVFILT_VNODE, EV_ADD | EV_ENABLE | EV_CLEAR, - NOTE_DELETE | NOTE_EXTEND | NOTE_WRITE | NOTE_RENAME, 0, 0); - if (kevent (kq, &ev, 1, NULL, 0, NULL) == -1) + /* Look for directories in both the old and new sets, if + * we find one, move its data into the new set. + */ + for (i = 0; new_dirs[i]; i++) { - _dbus_warn ("Cannot setup a kevent for '%s'; error '%s'\n", dir, _dbus_strerror (errno)); - close (fd); - goto out; + for (j = 0; i < num_fds; j++) + { + if (dirs[j] && strcmp (new_dirs[i], dirs[j]) == 0) + { + new_fds[i] = fds[j]; + new_dirs[i] = dirs[j]; + fds[j] = -1; + dirs[j] = NULL; + break; + } + } } - fds[num_fds++] = fd; - _dbus_verbose ("Added kqueue watch on config directory '%s'\n", dir); - - out: - ; -} - -void -bus_drop_all_directory_watches (void) -{ - int i; - - _dbus_verbose ("Dropping all watches on config directories\n"); + /* Any directory we find in "fds" with a nonzero fd must + * not be in the new set, so perform cleanup now. + */ + for (j = 0; j < num_fds; j++) + { + if (fds[j] != -1) + { + close (fds[j]); + dbus_free (dirs[j]); + fds[j] = -1; + dirs[j] = NULL; + } + } - for (i = 0; i < num_fds; i++) + for (i = 0; new_dirs[i]; i++) { - if (close (fds[i]) != 0) + if (new_fds[i] == -1) { - _dbus_verbose ("Error closing fd %d for config directory watch\n", fds[i]); + /* FIXME - less lame error handling for failing to add a watch; + * we may need to sleep. + */ + fd = open (new_dirs[i], O_RDONLY); + if (fd < 0) + { + _dbus_warn ("Cannot open directory '%s'; error '%s'\n", new_dirs[i], _dbus_strerror (errno)); + goto out; + } + + EV_SET (&ev, fd, EVFILT_VNODE, EV_ADD | EV_ENABLE | EV_CLEAR, + NOTE_DELETE | NOTE_EXTEND | NOTE_WRITE | NOTE_RENAME, 0, 0); + if (kevent (kq, &ev, 1, NULL, 0, NULL) == -1) + { + _dbus_warn ("Cannot setup a kevent for '%s'; error '%s'\n", dir, _dbus_strerror (errno)); + close (fd); + goto out; + } + + new_fds[i] = fd; + new_dirs[i] = _dbus_strdup (new_dirs[i]); + if (!new_dirs[i]) + { + /* FIXME have less lame handling for OOM, we just silently fail to + * watch. (In reality though, the whole OOM handling in dbus is + * stupid but we won't go into that in this comment =) ) + */ + close (fd); + new_fds[i] = -1; + } } } - num_fds = 0; + num_fds = i; + + for (i = 0; i < MAX_DIRS_TO_WATCH; i++) + { + fds[i] = new_fds[i]; + dirs[i] = new_dirs[i]; + } + + out: + ; } |