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authorCarlos O'Donell <carlos@redhat.com>2013-02-07 14:28:53 -0500
committerCarlos O'Donell <carlos@redhat.com>2013-02-08 12:56:22 -0500
commit471514d39d03ef96096767651ecce30630e64c1e (patch)
tree3d1dae1552063e42912511c83f74990502e8c3b0
parentb2d3c3befb45ae4e5284274d9ce75ca462119239 (diff)
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Refactor code out of nscd's two main poll loops.
We refactor the inotify file checking code and the database clearing code out of the main_loop_poll and mail_loop_epoll functions. We document some the related functions with appropriate comments.
-rw-r--r--ChangeLog10
-rw-r--r--nscd/connections.c148
2 files changed, 93 insertions, 65 deletions
diff --git a/ChangeLog b/ChangeLog
index ab411fd..7eb2265 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,15 @@
2013-02-08 Carlos O'Donell <carlos@redhat.com>
+ * nscd/connection.c (register_traced_file): Comment function.
+ [HAVE_INOTIFY] (union __inev): Define.
+ [HAVE_INOTIFY] (inotify_check_files): New function.
+ [HAVE_INOTIFY] (clear_db_cache): Likewise.
+ [HAVE_INOTIFY] (main_loop_poll): Call inotify_check_files and
+ clear_db_cache.
+ [HAVE_INOTIFY] (main_loop_epoll): Likewise.
+
+2013-02-08 Carlos O'Donell <carlos@redhat.com>
+
* elf/dl-cache.c (_dl_load_cache_lookup): Comment that cache is
loaded if not already and that a failure is permanent.
diff --git a/nscd/connections.c b/nscd/connections.c
index feda223..56c3279 100644
--- a/nscd/connections.c
+++ b/nscd/connections.c
@@ -976,9 +976,25 @@ cannot change socket to nonblocking mode: %s"),
}
+/* Register the file in FINFO as a traced file for the database DBS[DBIX].
+
+ We support registering multiple files per database. Each call to
+ register_traced_file adds to the list of registered files.
+
+ When we prune the database, either through timeout or a request to
+ invalidate, we will check to see if any of the registered files has changed.
+ When we accept new connections to handle a cache request we will also
+ check to see if any of the registered files has changed.
+
+ If we have inotify support then we install an inotify fd to notify us of
+ file deletion or modification, both of which will require we invalidate
+ the cache for the database. Without inotify support we stat the file and
+ store st_mtime to determine if the file has been modified. */
void
register_traced_file (size_t dbidx, struct traced_file *finfo)
{
+ /* If the database is disabled or file checking is disabled
+ then ignore the registration. */
if (! dbs[dbidx].enabled || ! dbs[dbidx].check_file)
return;
@@ -1870,6 +1886,63 @@ restart_p (time_t now)
/* Array for times a connection was accepted. */
static time_t *starttime;
+#ifdef HAVE_INOTIFY
+/* Inotify event for changed file. */
+union __inev
+{
+ struct inotify_event i;
+# ifndef PATH_MAX
+# define PATH_MAX 1024
+# endif
+ char buf[sizeof (struct inotify_event) + PATH_MAX];
+};
+
+/* Process the inotify event in INEV. If the event matches any of the files
+ registered with a database then mark that database as requiring its cache
+ to be cleared. We indicate the cache needs clearing by setting
+ TO_CLEAR[DBCNT] to true for the matching database. */
+static inline void
+inotify_check_files (bool *to_clear, union __inev *inev)
+{
+ /* Check which of the files changed. */
+ for (size_t dbcnt = 0; dbcnt < lastdb; ++dbcnt)
+ {
+ struct traced_file *finfo = dbs[dbcnt].traced_files;
+
+ while (finfo != NULL)
+ {
+ /* Inotify event watch descriptor matches. */
+ if (finfo->inotify_descr == inev->i.wd)
+ {
+ /* Mark cache as needing to be cleared and reinitialize. */
+ to_clear[dbcnt] = true;
+ if (finfo->call_res_init)
+ res_init ();
+ return;
+ }
+
+ finfo = finfo->next;
+ }
+ }
+}
+
+/* If an entry in the array of booleans TO_CLEAR is TRUE then clear the cache
+ for the associated database, otherwise do nothing. The TO_CLEAR array must
+ have LASTDB entries. */
+static inline void
+clear_db_cache (bool *to_clear)
+{
+ for (size_t dbcnt = 0; dbcnt < lastdb; ++dbcnt)
+ if (to_clear[dbcnt])
+ {
+ pthread_mutex_lock (&dbs[dbcnt].prune_lock);
+ dbs[dbcnt].clear_cache = 1;
+ pthread_mutex_unlock (&dbs[dbcnt].prune_lock);
+ pthread_cond_signal (&dbs[dbcnt].prune_cond);
+ }
+}
+
+#endif
static void
__attribute__ ((__noreturn__))
@@ -1976,15 +2049,10 @@ main_loop_poll (void)
if (conns[1].revents != 0)
{
bool to_clear[lastdb] = { false, };
- union
- {
-# ifndef PATH_MAX
-# define PATH_MAX 1024
-# endif
- struct inotify_event i;
- char buf[sizeof (struct inotify_event) + PATH_MAX];
- } inev;
+ union __inev inev;
+ /* Read all inotify events for files registered via
+ register_traced_file(). */
while (1)
{
ssize_t nb = TEMP_FAILURE_RETRY (read (inotify_fd, &inev,
@@ -2010,35 +2078,11 @@ disabled inotify after read error %d"),
}
/* Check which of the files changed. */
- for (size_t dbcnt = 0; dbcnt < lastdb; ++dbcnt)
- {
- struct traced_file *finfo = dbs[dbcnt].traced_files;
-
- while (finfo != NULL)
- {
- if (finfo->inotify_descr == inev.i.wd)
- {
- to_clear[dbcnt] = true;
- if (finfo->call_res_init)
- res_init ();
- goto next;
- }
-
- finfo = finfo->next;
- }
- }
- next:;
+ inotify_check_files (to_clear, &inev);
}
/* Actually perform the cache clearing. */
- for (size_t dbcnt = 0; dbcnt < lastdb; ++dbcnt)
- if (to_clear[dbcnt])
- {
- pthread_mutex_lock (&dbs[dbcnt].prune_lock);
- dbs[dbcnt].clear_cache = 1;
- pthread_mutex_unlock (&dbs[dbcnt].prune_lock);
- pthread_cond_signal (&dbs[dbcnt].prune_cond);
- }
+ clear_db_cache (to_clear);
--n;
}
@@ -2208,12 +2252,10 @@ main_loop_epoll (int efd)
else if (revs[cnt].data.fd == inotify_fd)
{
bool to_clear[lastdb] = { false, };
- union
- {
- struct inotify_event i;
- char buf[sizeof (struct inotify_event) + PATH_MAX];
- } inev;
+ union __inev inev;
+ /* Read all inotify events for files registered via
+ register_traced_file(). */
while (1)
{
ssize_t nb = TEMP_FAILURE_RETRY (read (inotify_fd, &inev,
@@ -2235,35 +2277,11 @@ main_loop_epoll (int efd)
}
/* Check which of the files changed. */
- for (size_t dbcnt = 0; dbcnt < lastdb; ++dbcnt)
- {
- struct traced_file *finfo = dbs[dbcnt].traced_files;
-
- while (finfo != NULL)
- {
- if (finfo->inotify_descr == inev.i.wd)
- {
- to_clear[dbcnt] = true;
- if (finfo->call_res_init)
- res_init ();
- goto next;
- }
-
- finfo = finfo->next;
- }
- }
- next:;
+ inotify_check_files(to_clear, &inev);
}
/* Actually perform the cache clearing. */
- for (size_t dbcnt = 0; dbcnt < lastdb; ++dbcnt)
- if (to_clear[dbcnt])
- {
- pthread_mutex_lock (&dbs[dbcnt].prune_lock);
- dbs[dbcnt].clear_cache = 1;
- pthread_mutex_unlock (&dbs[dbcnt].prune_lock);
- pthread_cond_signal (&dbs[dbcnt].prune_cond);
- }
+ clear_db_cache (to_clear);
}
# endif
# ifdef HAVE_NETLINK