X-Git-Url: http://www.chiark.greenend.org.uk/ucgi/~mdw/git/disorder/blobdiff_plain/7378b5081fde6f48140327d5c072a8231934f027..561d077df8d0494aeeaf3f30d847f489336cbfd6:/lib/trackdb.c

diff --git a/lib/trackdb.c b/lib/trackdb.c
index 53d7cf3..1b16445 100644
--- a/lib/trackdb.c
+++ b/lib/trackdb.c
@@ -2,20 +2,18 @@
  * This file is part of DisOrder
  * Copyright (C) 2005-2008 Richard Kettlewell
  *
- * This program is free software; you can redistribute it and/or modify
+ * 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
+ * the Free Software Foundation, either version 3 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.
- *
+ * 
+ * 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, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307
- * USA
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 /** @file lib/trackdb.c
  * @brief Track database
@@ -23,15 +21,11 @@
  * This file is getting in desparate need of splitting up...
  */
 
-#include <config.h>
-#include "types.h"
+#include "common.h"
 
-#include <string.h>
-#include <stdio.h>
 #include <db.h>
 #include <sys/socket.h>
 #include <pcre.h>
-#include <assert.h>
 #include <unistd.h>
 #include <errno.h>
 #include <stddef.h>
@@ -39,7 +33,6 @@
 #include <sys/resource.h>
 #include <time.h>
 #include <arpa/inet.h>
-#include <sys/wait.h>
 #include <dirent.h>
 #include <sys/stat.h>
 #include <gcrypt.h>
@@ -65,6 +58,7 @@
 #include "unicode.h"
 #include "unidata.h"
 #include "base64.h"
+#include "sendmail.h"
 
 #define RESCAN "disorder-rescan"
 #define DEADLOCK "disorder-deadlock"
@@ -88,8 +82,14 @@ int trackdb_existing_database;
 
 /* setup and teardown ********************************************************/
 
-static const char *home;                /* home had better not change */
-DB_ENV *trackdb_env;			/* db environment */
+/** @brief Database home directory
+ *
+ * All database files live below here.  It had better never change.
+ */
+static const char *home;
+
+/** @brief Database environment */
+DB_ENV *trackdb_env;
 
 /** @brief The tracks database
  * - Keys are UTF-8(NFC(unicode(path name)))
@@ -145,6 +145,17 @@ DB *trackdb_globaldb;                   /* global preferences */
  */
 DB *trackdb_noticeddb;                   /* when track noticed */
 
+/** @brief The schedule database
+ *
+ * - Keys are ID strings, generated at random
+ * - Values are encoded key-value pairs
+ * - There can be more than one value per key
+ * - Data cannot be reconstructed
+ *
+ * See @ref server/schedule.c for further information.
+ */
+DB *trackdb_scheduledb;
+
 /** @brief The user database
  * - Keys are usernames
  * - Values are encoded key-value pairs
@@ -152,11 +163,55 @@ DB *trackdb_noticeddb;                   /* when track noticed */
  */
 DB *trackdb_usersdb;
 
-static pid_t db_deadlock_pid = -1;      /* deadlock manager PID */
-static pid_t rescan_pid = -1;           /* rescanner PID */
-static int initialized, opened;         /* state */
+/** @brief The playlists database
+ * - Keys are playlist names
+ * - Values are encoded key-value pairs
+ * - Data is user data and cannot be reconstructed
+ */
+DB *trackdb_playlistsdb;
+
+/** @brief Deadlock manager PID */
+static pid_t db_deadlock_pid = -1;
+
+/** @brief Rescanner PID */
+static pid_t rescan_pid = -1;
+
+/** @brief Set when the database environment exists */
+static int initialized;
+
+/** @brief Set when databases are open */
+static int opened;
+
+/** @brief Current stats subprocess PIDs */
+static hash *stats_pids;
+
+/** @brief PID of current random track chooser (disorder-choose) */
+static pid_t choose_pid = -1;
+
+/** @brief Our end of pipe from disorder-choose */
+static int choose_fd;
+
+/** @brief Callback to supply random track to */
+static random_callback *choose_callback;
+
+/** @brief Accumulator for output from disorder-choose */
+static struct dynstr choose_output;
+
+/** @brief Current completion status of disorder-choose
+ * A bitmap of @ref CHOOSE_READING and @ref CHOOSE_RUNNING.
+ */
+static unsigned choose_complete;
+
+/* @brief Exit status from disorder-choose */
+static int choose_status;
+
+/** @brief disorder-choose process is running */
+#define CHOOSE_RUNNING 1
+
+/** @brief disorder-choose pipe is still open */
+#define CHOOSE_READING 2
 
-/* comparison function for keys */
+/** @brief Comparison function for filename-based keys */
 static int compare(DB attribute((unused)) *db_,
 		   const DBT *a, const DBT *b) {
   return compare_path_raw(a->data, a->size, b->data, b->size);
@@ -250,7 +305,7 @@ void trackdb_init(int flags) {
   D(("initialized database environment"));
 }
 
-/* called when deadlock manager terminates */
+/** @brief Called when deadlock manager terminates */
 static int reap_db_deadlock(ev_source attribute((unused)) *ev,
                             pid_t attribute((unused)) pid,
                             int status,
@@ -265,6 +320,18 @@ static int reap_db_deadlock(ev_source attribute((unused)) *ev,
   return 0;
 }
 
+/** @brief Start a subprogram
+ * @param ev Event loop
+ * @param outputfd File descriptor to redirect @c stdout to, or -1
+ * @param prog Program name
+ * @param ... Arguments
+ * @return PID
+ *
+ * Starts a subprocess.  Adds the following arguments:
+ * - @c --config to ensure the right config file is used
+ * - @c --debug or @c --no-debug to match debug settings
+ * - @c --syslog or @c --no-syslog to match log settings
+ */
 static pid_t subprogram(ev_source *ev, int outputfd, const char *prog,
                         ...) {
   pid_t pid;
@@ -304,7 +371,11 @@ static pid_t subprogram(ev_source *ev, int outputfd, const char *prog,
   return pid;
 }
 
-/* start deadlock manager */
+/** @brief Start deadlock manager
+ * @param ev Event loop
+ *
+ * Called from the main server (only).
+ */
 void trackdb_master(ev_source *ev) {
   assert(db_deadlock_pid == -1);
   db_deadlock_pid = subprogram(ev, -1, DEADLOCK, (char *)0);
@@ -312,8 +383,34 @@ void trackdb_master(ev_source *ev) {
   D(("started deadlock manager"));
 }
 
-/* close environment */
-void trackdb_deinit(void) {
+/** @brief Kill a subprocess and wait for it to terminate
+ * @param ev Event loop or NULL
+ * @param pid Process ID or -1
+ * @param what Description of subprocess
+ *
+ * Used during trackdb_deinit().  This function blocks so don't use it for
+ * normal teardown as that will hang the server.
+ */
+static void terminate_and_wait(ev_source *ev,
+                               pid_t pid,
+                               const char *what) {
+  int err;
+
+  if(pid == -1)
+    return;
+  if(kill(pid, SIGTERM) < 0)
+    fatal(errno, "error killing %s", what);
+  /* wait for the rescanner to finish */
+  while(waitpid(pid, &err, 0) == -1 && errno == EINTR)
+    ;
+  if(ev)
+    ev_child_cancel(ev, pid);
+}
+
+/** @brief Close database environment
+ * @param ev Event loop
+ */
+void trackdb_deinit(ev_source *ev) {
   int err;
 
   /* sanity checks */
@@ -324,32 +421,40 @@ void trackdb_deinit(void) {
   if((err = trackdb_env->close(trackdb_env, 0)))
     fatal(0, "trackdb_env->close: %s", db_strerror(err));
 
-  if(rescan_pid != -1) {
-    /* shut down the rescanner */
-    if(kill(rescan_pid, SIGTERM) < 0)
-      fatal(errno, "error killing rescanner");
-    /* wait for the rescanner to finish */
-    while(waitpid(rescan_pid, &err, 0) == -1 && errno == EINTR)
-      ;
-  }
+  terminate_and_wait(ev, rescan_pid, "disorder-rescan");
+  rescan_pid = -1;
+  terminate_and_wait(ev, choose_pid, "disorder-choose");
+  choose_pid = -1;
 
-  /* TODO kill any stats subprocesses */
+  if(stats_pids) {
+    char **ks = hash_keys(stats_pids);
 
-  /* finally terminate the deadlock manager */
-  if(db_deadlock_pid != -1 && kill(db_deadlock_pid, SIGTERM) < 0)
-    fatal(errno, "error killing deadlock manager");
-  db_deadlock_pid = -1;
+    while(*ks) {
+      pid_t pid = atoi(*ks++);
+      terminate_and_wait(ev, pid, "disorder-stats");
+    }
+    stats_pids = NULL;
+  }
 
+  terminate_and_wait(ev, db_deadlock_pid, "disorder-deadlock");
+  db_deadlock_pid = -1;
   D(("deinitialized database environment"));
 }
 
-/* open a specific database */
+/** @brief Open a specific database
+ * @param path Relative path to database
+ * @param dbflags Database flags: DB_DUP, DB_DUPSORT, etc
+ * @param dbtype Database type: DB_HASH, DB_BTREE, etc
+ * @param openflags Open flags: DB_RDONLY, DB_CREATE, etc
+ * @param mode Permission mask: usually 0666
+ * @return Database handle
+ */
 static DB *open_db(const char *path,
                    u_int32_t dbflags,
                    DBTYPE dbtype,
                    u_int32_t openflags,
                    int mode) {
-  int err;
+  int err, err2;
   DB *db;
 
   D(("open %s", path));
@@ -364,8 +469,14 @@ static DB *open_db(const char *path,
       fatal(0, "db->set_bt_compare %s: %s", path, db_strerror(err));
   if((err = db->open(db, 0, path, 0, dbtype,
                      openflags | DB_AUTO_COMMIT, mode))) {
-    if((openflags & DB_CREATE) || errno != ENOENT)
+    if((openflags & DB_CREATE) || errno != ENOENT) {
+      if((err2 = db->close(db, 0)))
+        error(0, "db->close: %s", db_strerror(err2));
+      trackdb_close();
+      trackdb_env->close(trackdb_env,0);
+      trackdb_env = 0;
       fatal(0, "db->open %s: %s", path, db_strerror(err));
+    }
     db->close(db, 0);
     db = 0;
   }
@@ -460,7 +571,9 @@ void trackdb_open(int flags) {
   trackdb_globaldb = open_db("global.db", 0, DB_HASH, dbflags, 0666);
   trackdb_noticeddb = open_db("noticed.db",
                              DB_DUPSORT, DB_BTREE, dbflags, 0666);
-  if(!trackdb_existing_database) {
+  trackdb_scheduledb = open_db("schedule.db", 0, DB_HASH, dbflags, 0666);
+  trackdb_playlistsdb = open_db("playlists.db", 0, DB_HASH, dbflags, 0666);
+  if(!trackdb_existing_database && !(flags & TRACKDB_READ_ONLY)) {
     /* Stash the database version */
     char buf[32];
 
@@ -471,36 +584,39 @@ void trackdb_open(int flags) {
   D(("opened databases"));
 }
 
-/* close track databases */
+/** @brief Close track databases */
 void trackdb_close(void) {
   int err;
 
   /* sanity checks */
   assert(opened == 1);
   --opened;
-  if((err = trackdb_tracksdb->close(trackdb_tracksdb, 0)))
-    fatal(0, "error closing tracks.db: %s", db_strerror(err));
-  if((err = trackdb_searchdb->close(trackdb_searchdb, 0)))
-    fatal(0, "error closing search.db: %s", db_strerror(err));
-  if((err = trackdb_tagsdb->close(trackdb_tagsdb, 0)))
-    fatal(0, "error closing tags.db: %s", db_strerror(err));
-  if((err = trackdb_prefsdb->close(trackdb_prefsdb, 0)))
-    fatal(0, "error closing prefs.db: %s", db_strerror(err));
-  if((err = trackdb_globaldb->close(trackdb_globaldb, 0)))
-    fatal(0, "error closing global.db: %s", db_strerror(err));
-  if((err = trackdb_noticeddb->close(trackdb_noticeddb, 0)))
-    fatal(0, "error closing noticed.db: %s", db_strerror(err));
-  if((err = trackdb_usersdb->close(trackdb_usersdb, 0)))
-    fatal(0, "error closing users.db: %s", db_strerror(err));
-  trackdb_tracksdb = trackdb_searchdb = trackdb_prefsdb = 0;
-  trackdb_tagsdb = trackdb_globaldb = 0;
+#define CLOSE(N, V) do {                                        \
+  if(V && (err = V->close(V, 0)))                               \
+    fatal(0, "error closing %s: %s", N, db_strerror(err));      \
+  V = 0;                                                        \
+} while(0)
+  CLOSE("tracks.db", trackdb_tracksdb);
+  CLOSE("search.db", trackdb_searchdb);
+  CLOSE("tags.db", trackdb_tagsdb);
+  CLOSE("prefs.db", trackdb_prefsdb);
+  CLOSE("global.db", trackdb_globaldb);
+  CLOSE("noticed.db", trackdb_noticeddb);
+  CLOSE("schedule.db", trackdb_scheduledb);
+  CLOSE("users.db", trackdb_usersdb);
+  CLOSE("playlists.db", trackdb_playlistsdb);
   D(("closed databases"));
 }
 
 /* generic db routines *******************************************************/
 
-/* fetch and decode a database entry.  Returns 0, DB_NOTFOUND or
- * DB_LOCK_DEADLOCK. */
+/** @brief Fetch and decode a database entry
+ * @param db Database
+ * @param track Track name
+ * @param kp Where to put decoded list (or NULL if you don't care)
+ * @param tid Owning transaction
+ * @return 0, @c DB_NOTFOUND or @c DB_LOCK_DEADLOCK
+ */
 int trackdb_getdata(DB *db,
                     const char *track,
                     struct kvp **kp,
@@ -511,10 +627,12 @@ int trackdb_getdata(DB *db,
   switch(err = db->get(db, tid, make_key(&key, track),
                        prepare_data(&data), 0)) {
   case 0:
-    *kp = kvp_urldecode(data.data, data.size);
+    if(kp)
+      *kp = kvp_urldecode(data.data, data.size);
     return 0;
   case DB_NOTFOUND:
-    *kp = 0;
+    if(kp)
+      *kp = 0;
     return err;
   case DB_LOCK_DEADLOCK:
     error(0, "error querying database: %s", db_strerror(err));
@@ -524,8 +642,14 @@ int trackdb_getdata(DB *db,
   }
 }
 
-/* encode and store a database entry.  Returns 0, DB_KEYEXIST or
- * DB_LOCK_DEADLOCK. */
+/** @brief Encode and store a database entry
+ * @param db Database
+ * @param track Track name
+ * @param k List of key/value pairs to store
+ * @param tid Owning transaction
+ * @param flags DB flags e.g. DB_NOOVERWRITE
+ * @return 0, DB_KEYEXIST or DB_LOCK_DEADLOCK
+ */
 int trackdb_putdata(DB *db,
                     const char *track,
                     const struct kvp *k,
@@ -571,7 +695,11 @@ int trackdb_delkey(DB *db,
   }
 }
 
-/* open a database cursor */
+/** @brief Open a database cursor
+ * @param db Database
+ * @param tid Owning transaction
+ * @return Cursor
+ */
 DBC *trackdb_opencursor(DB *db, DB_TXN *tid) {
   int err;
   DBC *c;
@@ -583,7 +711,10 @@ DBC *trackdb_opencursor(DB *db, DB_TXN *tid) {
   return c;
 }
 
-/* close a database cursor; returns 0 or DB_LOCK_DEADLOCK */
+/** @brief Close a database cursor
+ * @param c Cursor
+ * @return 0 or DB_LOCK_DEADLOCK
+ */
 int trackdb_closecursor(DBC *c) {
   int err;
 
@@ -599,7 +730,16 @@ int trackdb_closecursor(DBC *c) {
   }
 }
 
-/* delete a (key,data) pair.  Returns 0, DB_NOTFOUND or DB_LOCK_DEADLOCK. */
+/** @brief Delete a key/data pair
+ * @param db Database
+ * @param word Key
+ * @param track Data
+ * @param tid Owning transaction
+ * @return 0, DB_NOTFOUND or DB_LOCK_DEADLOCK
+ *
+ * Used by the search and tags databases, hence the odd parameter names.
+ * See also register_word().
+ */
 int trackdb_delkeydata(DB *db,
                        const char *word,
                        const char *track,
@@ -637,7 +777,9 @@ int trackdb_delkeydata(DB *db,
   return err;
 }
 
-/* start a transaction */
+/** @brief Start a transaction
+ * @return Transaction
+ */
 DB_TXN *trackdb_begin_transaction(void) {
   DB_TXN *tid;
   int err;
@@ -647,7 +789,11 @@ DB_TXN *trackdb_begin_transaction(void) {
   return tid;
 }
 
-/* abort transaction */
+/** @brief Abort transaction
+ * @param tid Transaction (or NULL)
+ *
+ * If @p tid is NULL then nothing happens.
+ */
 void trackdb_abort_transaction(DB_TXN *tid) {
   int err;
 
@@ -656,7 +802,9 @@ void trackdb_abort_transaction(DB_TXN *tid) {
       fatal(0, "tid->abort: %s", db_strerror(err));
 }
 
-/* commit transaction */
+/** @brief Commit transaction
+ * @param tid Transaction (must not be NULL)
+ */
 void trackdb_commit_transaction(DB_TXN *tid) {
   int err;
 
@@ -666,12 +814,26 @@ void trackdb_commit_transaction(DB_TXN *tid) {
 
 /* search/tags shared code ***************************************************/
 
-/* comparison function used by dedupe() */
+/** @brief Comparison function used by dedupe()
+ * @param a Pointer to first key
+ * @param b Pointer to second key
+ * @return -1, 0 or 1
+ *
+ * Passed to qsort().
+ */
 static int wordcmp(const void *a, const void *b) {
   return strcmp(*(const char **)a, *(const char **)b);
 }
 
-/* sort and de-dupe VEC */
+/** @brief Sort and de-duplicate @p vec
+ * @param vec Vector to sort
+ * @param nvec Length of @p vec
+ * @return @p vec
+ *
+ * The returned vector is NULL-terminated, and there must be room for this NULL
+ * even if there are no duplicates (i.e. it must have more than @p nvec
+ * elements.)
+ */
 static char **dedupe(char **vec, int nvec) {
   int m, n;
 
@@ -687,7 +849,17 @@ static char **dedupe(char **vec, int nvec) {
   return vec;
 }
 
-/* update a key/track database.  Returns 0 or DB_DEADLOCK. */
+/** @brief Store a key/data pair
+ * @param db Database
+ * @param what Description
+ * @param track Data
+ * @param word Key
+ * @param tid Owning transaction
+ * @return 0 or DB_DEADLOCK
+ *
+ * Used by the search and tags databases, hence the odd parameter names.
+ * See also trackdb_delkeydata().
+ */
 static int register_word(DB *db, const char *what,
                          const char *track, const char *word,
                          DB_TXN *tid) {
@@ -709,13 +881,22 @@ static int register_word(DB *db, const char *what,
 
 /* search primitives *********************************************************/
 
-/* return true iff NAME is a trackname_display_ pref */
+/** @brief Return true iff @p name is a trackname_display_ pref
+ * @param name Preference name
+ * @return Non-zero iff @p name is a trackname_display_ pref
+ */
 static int is_display_pref(const char *name) {
   static const char prefix[] = "trackname_display_";
   return !strncmp(name, prefix, (sizeof prefix) - 1);
 }
 
-/** @brief Word_Break property tailor that treats underscores as spaces */
+/** @brief Word_Break property tailor that treats underscores as spaces
+ * @param c Code point
+ * @return Tailored property or -1 to use standard value
+ *
+ * Passed to utf32_word_split() when splitting a track name into words.
+ * See word_split() and @ref unicode_property_tailor.
+ */
 static int tailor_underscore_Word_Break_Other(uint32_t c) {
   switch(c) {
   default:
@@ -741,7 +922,20 @@ static size_t remove_combining_chars(uint32_t *s, size_t ns) {
   return t - start;
 }
 
-/** @brief Normalize and split a string using a given tailoring */
+/** @brief Normalize and split a string using a given tailoring
+ * @param v Where to store words from string
+ * @param s Input string
+ * @param pt Word_Break property tailor, or NULL
+ *
+ * The output words will be:
+ * - case-folded
+ * - have any combination characters stripped
+ * - not include any word break code points (as tailored)
+ *
+ * Used by track_to_words(), with @p pt set to @ref
+ * tailor_underscore_Word_Break_Other, and by normalize_tag() with no
+ * tailoring.
+ */
 static void word_split(struct vector *v,
                        const char *s,
                        unicode_property_tailor *pt) {
@@ -797,7 +991,11 @@ static char *normalize_tag(const char *s, size_t ns) {
   return d->vec;
 }
 
-/* compute the words of a track name */
+/** @brief Compute the words of a track name
+ * @param track Track name
+ * @param p Preferences (for display prefs)
+ * @return NULL-terminated, de-duplicated list or words
+ */
 static char **track_to_words(const char *track,
                              const struct kvp *p) {
   struct vector v;
@@ -815,7 +1013,10 @@ static char **track_to_words(const char *track,
   return dedupe(v.vec, v.nvec);
 }
 
-/* return nonzero iff WORD is a stopword */
+/** @brief Test for a stopword
+ * @param word Word
+ * @return Non-zero if @p word is a stopword
+ */
 static int stopword(const char *word) {
   int n;
 
@@ -825,7 +1026,12 @@ static int stopword(const char *word) {
   return n < config->stopword.n;
 }
 
-/* record that WORD appears in TRACK.  Returns 0 or DB_LOCK_DEADLOCK. */
+/** @brief Register a search term
+ * @param track Track name
+ * @param word A word that appears in the name of @p track
+ * @param tid Owning transaction
+ * @return  0 or DB_LOCK_DEADLOCK
+ */
 static int register_search_word(const char *track, const char *word,
                                 DB_TXN *tid) {
   if(stopword(word)) return 0;
@@ -834,7 +1040,13 @@ static int register_search_word(const char *track, const char *word,
 
 /* Tags **********************************************************************/
 
-/* Return nonzero if C is a valid tag character */
+/** @brief Test for tag characters
+ * @param c Character
+ * @return Non-zero if @p c is a tag character
+ *
+ * The current rule is that commas and the control characters 0-31 are not
+ * allowed but anything else is permitted.  This is arguably a bit loose.
+ */
 static int tagchar(int c) {
   switch(c) {
   case ',':
@@ -844,7 +1056,12 @@ static int tagchar(int c) {
   }
 }
 
-/* Parse and de-dupe a tag list.  If S=0 then assumes "". */
+/** @brief Parse a tag list
+ * @param s Tag list or NULL (equivalent to "")
+ * @return Parsed tag list
+ *
+ * The tags will be normalized (as per normalize_tag()) and de-duplicated.
+ */
 char **parsetags(const char *s) {
   const char *t;
   struct vector v;
@@ -873,7 +1090,12 @@ char **parsetags(const char *s) {
   return dedupe(v.vec, v.nvec);
 }
 
-/* Record that TRACK has TAG.  Returns 0 or DB_LOCK_DEADLOCK. */
+/** @brief Register a tag
+ * @param track Track name
+ * @param tag Tag name
+ * @param tid Owning transaction
+ * @return 0 or DB_LOCK_DEADLOCK
+ */
 static int register_tag(const char *track, const char *tag, DB_TXN *tid) {
   return register_word(trackdb_tagsdb, "tags", track, tag, tid);
 }
@@ -1014,7 +1236,8 @@ int trackdb_notice_tid(const char *track,
   int err, n;
   struct kvp *t, *a, *p;
   int t_changed, ret;
-  char *alias, **w;
+  char *alias, **w, *noticed;
+  time_t now;
 
   /* notice whether the tracks.db entry changes */
   t_changed = 0;
@@ -1025,6 +1248,12 @@ int trackdb_notice_tid(const char *track,
   /* this is a real track */
   t_changed += kvp_set(&t, "_alias_for", 0);
   t_changed += kvp_set(&t, "_path", path);
+  xtime(&now);
+  if(ret == DB_NOTFOUND) {
+    /* It's a new track; record the time */
+    byte_xasprintf(&noticed, "%lld", (long long)now);
+    t_changed += kvp_set(&t, "_noticed", noticed);
+  }
   /* if we have an alias record it in the database */
   if((err = compute_alias(&alias, track, p, tid))) return err;
   if(alias) {
@@ -1049,10 +1278,8 @@ int trackdb_notice_tid(const char *track,
     return err;
   if(ret == DB_NOTFOUND) {
     uint32_t timestamp[2];
-    time_t now;
     DBT key, data;
 
-    time(&now);
     timestamp[0] = htonl((uint64_t)now >> 32);
     timestamp[1] = htonl((uint32_t)now);
     memset(&key, 0, sizeof key);
@@ -1325,7 +1552,7 @@ static void stats_complete(struct stats_details *d) {
 }
 
 static int stats_finished(ev_source attribute((unused)) *ev,
-                          pid_t attribute((unused)) pid,
+                          pid_t pid,
                           int status,
                           const struct rusage attribute((unused)) *rusage,
                           void *u) {
@@ -1335,6 +1562,9 @@ static int stats_finished(ev_source attribute((unused)) *ev,
   if(status)
     error(0, "disorder-stats %s", wstat(status));
   stats_complete(d);
+  char *k;
+  byte_xasprintf(&k, "%lu", (unsigned long)pid);
+  hash_remove(stats_pids, k);
   return 0;
 }
 
@@ -1379,7 +1609,69 @@ void trackdb_stats_subprocess(ev_source *ev,
   pid = subprogram(ev, p[1], "disorder-stats", (char *)0);
   xclose(p[1]);
   ev_child(ev, pid, 0, stats_finished, d);
-  ev_reader_new(ev, p[0], stats_read, stats_error, d, "disorder-stats reader");
+  if(!ev_reader_new(ev, p[0], stats_read, stats_error, d,
+                    "disorder-stats reader"))
+    fatal(0, "ev_reader_new for disorder-stats reader failed");
+  /* Remember the PID */
+  if(!stats_pids)
+    stats_pids = hash_new(1);
+  char *k;
+  byte_xasprintf(&k, "%lu", (unsigned long)pid);
+  hash_add(stats_pids, k, "", HASH_INSERT);
+}
+
+/** @brief Parse a track name part preference
+ * @param name Preference name
+ * @param partp Where to store part name
+ * @param contextp Where to store context name
+ * @return 0 on success, non-0 if parse fails
+ */
+static int trackdb__parse_namepref(const char *name,
+                                   char **partp,
+                                   char **contextp) {
+  char *c;
+  static const char prefix[] = "trackname_";
+  
+  if(strncmp(name, prefix, strlen(prefix)))
+    return -1;                          /* not trackname_* at all */
+  name += strlen(prefix);
+  /* There had better be a _ between context and part */
+  c = strchr(name, '_');
+  if(!c)
+    return -1;
+  /* Context is first in the pref name even though most APIs have the part
+   * first.  Confusing; sorry. */
+  *contextp = xstrndup(name, c - name);
+  ++c;
+  /* There had better NOT be a second _ */
+  if(strchr(c, '_'))
+    return -1;
+  *partp = xstrdup(c);
+  return 0;
+}
+
+/** @brief Compute the default value for a track preference
+ * @param track Track name
+ * @param name Preference name
+ * @return Default value or 0 if none/not known
+ */
+static const char *trackdb__default(const char *track, const char *name) {
+  char *context, *part;
+  
+  if(!trackdb__parse_namepref(name, &part, &context)) {
+    /* We can work out the default for a trackname_ pref */
+    return trackname_part(track, context, part);
+  } else if(!strcmp(name, "weight")) {
+    /* We know the default weight */
+    return "90000";
+  } else if(!strcmp(name, "pick_at_random")) {
+    /* By default everything is eligible for picking at random */
+    return "1";
+  } else if(!strcmp(name, "tags")) {
+    /* By default everything no track has any tags */
+    return "";
+  }
+  return 0;
 }
 
 /* set a pref (remove if value=0) */
@@ -1390,9 +1682,15 @@ int trackdb_set(const char *track,
   DB_TXN *tid;
   int err, cmp;
   char *oldalias, *newalias, **oldtags = 0, **newtags;
+  const char *def;
 
+  /* If the value matches the default then unset instead, to keep the database
+   * tidy.  Older versions did not have this feature so your database may yet
+   * have some default values stored in it. */
   if(value) {
-    /* TODO: if value matches default then set value=0 */
+    def = trackdb__default(track, name);
+    if(def && !strcmp(value, def))
+      value = 0;
   }
 
   for(;;) {
@@ -1592,15 +1890,6 @@ int tag_intersection(char **a, char **b) {
   return 0;
 }
 
-static pid_t choose_pid = -1;
-static int choose_fd;
-static random_callback *choose_callback;
-static struct dynstr choose_output;
-static unsigned choose_complete;
-static int choose_status;
-#define CHOOSE_RUNNING 1
-#define CHOOSE_READING 2
-
 static void choose_finished(ev_source *ev, unsigned which) {
   choose_complete |= which;
   if(choose_complete != (CHOOSE_RUNNING|CHOOSE_READING))
@@ -1675,8 +1964,9 @@ int trackdb_request_random(ev_source *ev,
   choose_callback = callback;
   choose_output.nvec = 0;
   choose_complete = 0;
-  ev_reader_new(ev, p[0], choose_readable, choose_read_error, 0,
-                "disorder-choose reader"); /* owns p[0] */
+  if(!ev_reader_new(ev, p[0], choose_readable, choose_read_error, 0,
+                    "disorder-choose reader")) /* owns p[0] */
+    fatal(0, "ev_reader_new for disorder-choose reader failed");
   ev_child(ev, choose_pid, 0, choose_exited, 0); /* owns the subprocess */
   return 0;
 }
@@ -1778,7 +2068,7 @@ static int do_list(struct vector *v, const char *dir,
   char *ptr;
   int err;
   size_t l, last_dir_len = 0;
-  char *last_dir = 0, *track, *alias;
+  char *last_dir = 0, *track;
   struct kvp *p;
 
   dl = strlen(dir);
@@ -1811,12 +2101,35 @@ static int do_list(struct vector *v, const char *dir,
         if((err = trackdb_getdata(trackdb_prefsdb,
                                   track, &p, tid)) == DB_LOCK_DEADLOCK)
           goto deadlocked;
+        /* There's an awkward question here...
+         *
+         * If a track shares a directory with its alias then we could
+         * do one of three things:
+         * - report both.  Looks ridiculuous in most UIs.
+         * - report just the alias.  Remarkably inconvenient to write
+         *   UI code for!
+         * - report just the real name.  Ugly if the UI doesn't prettify
+         *   names via the name parts.
+         */
+#if 1
+        /* If this file is an alias for a track in the same directory then we
+         * skip it */
+        struct kvp *t = kvp_urldecode(d.data, d.size);
+        const char *alias_target = kvp_get(t, "_alias_for");
+        if(!(alias_target
+             && !strcmp(d_dirname(alias_target),
+                        d_dirname(track))))
+	  if(track_matches(dl, k.data, k.size, re))
+	    vector_append(v, track);
+#else
 	/* if this file has an alias in the same directory then we skip it */
+           char *alias;
         if((err = compute_alias(&alias, track, p, tid)))
           goto deadlocked;
         if(!(alias && !strcmp(d_dirname(alias), d_dirname(track))))
 	  if(track_matches(dl, k.data, k.size, re))
 	    vector_append(v, track);
+#endif
       }
     }
     err = cursor->c_get(cursor, &k, &d, DB_NEXT);
@@ -2092,6 +2405,28 @@ int trackdb_scan(const char *root,
 
 /* trackdb_rescan ************************************************************/
 
+/** @brief Node in the list of rescan-complete callbacks */
+struct rescanned_node {
+  struct rescanned_node *next;
+  void (*rescanned)(void *ru);
+  void *ru;
+};
+
+/** @brief List of rescan-complete callbacks */
+static struct rescanned_node *rescanned_list;
+
+/** @brief Add a rescan completion callback */
+void trackdb_add_rescanned(void (*rescanned)(void *ru),
+                           void *ru) {
+  if(rescanned) {
+    struct rescanned_node *n = xmalloc(sizeof *n);
+    n->next = rescanned_list;
+    n->rescanned = rescanned;
+    n->ru = ru;
+    rescanned_list = n;
+  }
+}
+
 /* called when the rescanner terminates */
 static int reap_rescan(ev_source attribute((unused)) *ev,
                        pid_t pid,
@@ -2106,23 +2441,37 @@ static int reap_rescan(ev_source attribute((unused)) *ev,
   /* Our cache of file lookups is out of date now */
   cache_clean(&cache_files_type);
   eventlog("rescanned", (char *)0);
+  /* Call rescanned callbacks */
+  while(rescanned_list) {
+    void (*rescanned)(void *u_) = rescanned_list->rescanned;
+    void *ru = rescanned_list->ru;
+
+    rescanned_list = rescanned_list->next;
+    rescanned(ru);
+  }
   return 0;
 }
 
 /** @brief Initiate a rescan
  * @param ev Event loop or 0 to block
  * @param recheck 1 to recheck lengths, 0 to suppress check
+ * @param rescanned Called on completion (if not NULL)
+ * @param ru Passed to @p rescanned
  */
-void trackdb_rescan(ev_source *ev, int recheck) {
+void trackdb_rescan(ev_source *ev, int recheck,
+                    void (*rescanned)(void *ru),
+                    void *ru) {
   int w;
 
   if(rescan_pid != -1) {
+    trackdb_add_rescanned(rescanned, ru);
     error(0, "rescan already underway");
     return;
   }
   rescan_pid = subprogram(ev, -1, RESCAN,
                           recheck ? "--check" : "--no-check",
                           (char *)0);
+  trackdb_add_rescanned(rescanned, ru);
   if(ev) {
     ev_child(ev, rescan_pid, 0, reap_rescan, 0);
     D(("started rescanner"));
@@ -2142,6 +2491,11 @@ int trackdb_rescan_cancel(void) {
   return 1;
 }
 
+/** @brief Return true if a rescan is underway */
+int trackdb_rescan_underway(void) {
+  return rescan_pid != -1;
+}
+
 /* global prefs **************************************************************/
 
 void trackdb_set_global(const char *name,
@@ -2276,12 +2630,24 @@ static char **trackdb_new_tid(int *ntracksp,
   DBT k, d;
   int err = 0;
   struct vector tracks[1];
+  hash *h = hash_new(1);
 
   vector_init(tracks);
   c = trackdb_opencursor(trackdb_noticeddb, tid);
   while((maxtracks <= 0 || tracks->nvec < maxtracks)
-        && !(err = c->c_get(c, prepare_data(&k), prepare_data(&d), DB_PREV)))
-    vector_append(tracks, xstrndup(d.data, d.size));
+        && !(err = c->c_get(c, prepare_data(&k), prepare_data(&d), DB_PREV))) {
+    char *const track = xstrndup(d.data, d.size);
+    /* Don't add any track more than once */
+    if(hash_add(h, track, "", HASH_INSERT))
+      continue;
+    /* See if the track still exists */
+    err = trackdb_getdata(trackdb_tracksdb, track, NULL/*kp*/, tid);
+    if(err == DB_NOTFOUND)
+      continue;                         /* It doesn't, skip it */
+    if(err == DB_LOCK_DEADLOCK)
+      break;                            /* Doh */
+    vector_append(tracks, track);
+  }
   switch(err) {
   case 0:                               /* hit maxtracks */
   case DB_NOTFOUND:                     /* ran out of tracks */
@@ -2393,8 +2759,10 @@ static int trusted(const char *user) {
  * Currently we only allow the letters and digits in ASCII.  We could be more
  * liberal than this but it is a nice simple test.  It is critical that
  * semicolons are never allowed.
+ *
+ * NB also used by playlist_parse_name() to validate playlist names!
  */
-static int valid_username(const char *user) {
+int valid_username(const char *user) {
   if(!*user)
     return 0;
   while(*user) {
@@ -2438,7 +2806,7 @@ static int create_user(const char *user,
     kvp_set(&k, "email", email);
   if(confirmation)
     kvp_set(&k, "confirmation", confirmation);
-  snprintf(s, sizeof s, "%jd", (intmax_t)time(0));
+  snprintf(s, sizeof s, "%jd", (intmax_t)xtime(0));
   kvp_set(&k, "created", s);
   return trackdb_putdata(trackdb_usersdb, user, k, tid, flags);
 }
@@ -2563,6 +2931,7 @@ int trackdb_adduser(const char *user,
            user, rights, email);
     else
       info("created user '%s' with rights '%s'", user, rights);
+    eventlog("user_add", user, (char *)0);
     return 0;
   }
 }
@@ -2580,6 +2949,7 @@ int trackdb_deluser(const char *user) {
     return -1;
   }
   info("deleted user '%s'", user);
+  eventlog("user_delete", user, (char *)0);
   return 0;
 }
 
@@ -2641,8 +3011,8 @@ int trackdb_edituserinfo(const char *user,
     }
   } else if(!strcmp(key, "email")) {
     if(*value) {
-      if(!strchr(value, '@')) {
-        error(0, "invalid email address '%s' for user '%s'", user, value);
+      if(!email_valid(value)) {
+        error(0, "invalid email address '%s' for user '%s'", value, user);
         return -1;
       }
     } else
@@ -2659,8 +3029,10 @@ int trackdb_edituserinfo(const char *user,
   if(e) {
     error(0, "unknown user '%s'", user);
     return -1;
-  } else
+  } else {
+    eventlog("user_edit", user, key, (char *)0);
     return 0;
+  }
 }
 
 /** @brief List all users
@@ -2726,6 +3098,7 @@ int trackdb_confirm(const char *user, const char *confirmation,
   switch(e) {
   case 0:
     info("registration confirmed for user '%s'", user);
+    eventlog("user_confirm", user, (char *)0);
     return 0;
   case DB_NOTFOUND:
     error(0, "confirmation for nonexistent user '%s'", user);