X-Git-Url: http://git.tuebingen.mpg.de/?p=paraslash.git;a=blobdiff_plain;f=aft.c;h=f14440e6fb903548e25ccfdf611f4c2f2881aa49;hp=96f65e99fbf5b1bd2ae7eb863b864ce77e743c70;hb=33692c33f2effa9620064aec44c6196a8d830d05;hpb=837cd1ab890645d9fd7d0d85139fdf076d987ea4

diff --git a/aft.c b/aft.c
index 96f65e99..f14440e6 100644
--- a/aft.c
+++ b/aft.c
@@ -241,19 +241,12 @@ enum audio_file_table_columns {
 	NUM_AFT_COLUMNS
 };
 
-/**
- * Compare two osl objects pointing to hash values.
- *
- * \param obj1 Pointer to the first hash object.
- * \param obj2 Pointer to the second hash object.
- *
- * \return The values required for an osl compare function.
- *
- * \sa osl_compare_func, uint32_compare().
- */
-static int aft_hash_compare(const struct osl_object *obj1, const struct osl_object *obj2)
+/* compare function for the hash column */
+static int aft_hash_compare(const struct osl_object *obj1,
+		const struct osl_object *obj2)
 {
-	return hash_compare((unsigned char *)obj1->data, (unsigned char *)obj2->data);
+	return hash_compare((unsigned char *)obj1->data,
+		(unsigned char *)obj2->data);
 }
 
 static struct osl_column_description aft_cols[] = {
@@ -683,21 +676,33 @@ int load_afd(int shmid, struct audio_file_data *afd)
 static int get_local_time(uint64_t *seconds, char *buf, size_t size,
 	time_t current_time, enum ls_listing_mode lm)
 {
-	struct tm t;
+	struct tm *tm;
+	/*
+	 * Omit year but show time if the given value is closer to the current
+	 * time than this many seconds.
+	 */
+	const time_t m = 6 * 30 * 24 * 3600; /* six months */
 
-	if (!localtime_r((time_t *)seconds, &t))
+	tm = localtime((time_t *)seconds);
+	if (!tm)
 		return -E_LOCALTIME;
 	if (lm == LS_MODE_MBOX) {
-		if (!strftime(buf, size, "%c", &t))
+		if (!strftime(buf, size, "%c", tm))
 			return -E_STRFTIME;
 		return 1;
 	}
-	if (*seconds + 6 * 30 * 24 * 3600 > current_time) {
-		if (!strftime(buf, size, "%b %e %k:%M", &t))
+	if (*seconds > current_time - m && *seconds < current_time + m) {
+		if (!strftime(buf, size, "%b %e %k:%M", tm))
 			return -E_STRFTIME;
 		return 1;
 	}
-	if (!strftime(buf, size, "%b %e  %Y", &t))
+	/*
+	 * If the given time is more than six month away from the current time,
+	 * we print only the year. The additional space character in the format
+	 * string below makes the formated date align nicely with dates that
+	 * contain the time (those written by the above strftime() statement).
+	 */
+	if (!strftime(buf, size, "%b %e  %Y", tm))
 		return -E_STRFTIME;
 	return 1;
 }
@@ -748,62 +753,50 @@ static int write_attribute_items(struct para_buffer *b,
 	char *att_text;
 	int ret;
 
-	ret = WRITE_STATUS_ITEM(b, SI_ATTRIBUTES_BITMAP, "%s\n", att_bitmap);
-	if (ret < 0)
-		return ret;
+	WRITE_STATUS_ITEM(b, SI_ATTRIBUTES_BITMAP, "%s\n", att_bitmap);
 	ret = get_attribute_text(&afsi->attributes, " ", &att_text);
 	if (ret < 0)
 		return ret;
-	ret = WRITE_STATUS_ITEM(b, SI_ATTRIBUTES_TXT, "%s\n", att_text);
+	WRITE_STATUS_ITEM(b, SI_ATTRIBUTES_TXT, "%s\n", att_text);
 	free(att_text);
 	return ret;
 }
 
-static int write_lyrics_items(struct para_buffer *b, struct afs_info *afsi)
+static void write_lyrics_items(struct para_buffer *b, struct afs_info *afsi)
 {
 	char *lyrics_name;
-	int ret;
 
-	ret = WRITE_STATUS_ITEM(b, SI_LYRICS_ID, "%u\n", afsi->lyrics_id);
-	if (ret < 0)
-		return ret;
+	WRITE_STATUS_ITEM(b, SI_LYRICS_ID, "%u\n", afsi->lyrics_id);
 	lyr_get_name_by_id(afsi->lyrics_id, &lyrics_name);
-	return WRITE_STATUS_ITEM(b, SI_LYRICS_NAME, "%s\n", lyrics_name?
+	WRITE_STATUS_ITEM(b, SI_LYRICS_NAME, "%s\n", lyrics_name?
 		lyrics_name : "(none)");
 }
 
-static int write_image_items(struct para_buffer *b, struct afs_info *afsi)
+static void write_image_items(struct para_buffer *b, struct afs_info *afsi)
 {
 	char *image_name;
-	int ret;
 
-	ret = WRITE_STATUS_ITEM(b, SI_IMAGE_ID, "%u\n", afsi->image_id);
-	if (ret < 0)
-		return ret;
+	WRITE_STATUS_ITEM(b, SI_IMAGE_ID, "%u\n", afsi->image_id);
 	img_get_name_by_id(afsi->image_id, &image_name);
-	return WRITE_STATUS_ITEM(b, SI_IMAGE_NAME, "%s\n", image_name?
+	WRITE_STATUS_ITEM(b, SI_IMAGE_NAME, "%s\n", image_name?
 		image_name : "(none)");
 }
 
-static int write_filename_items(struct para_buffer *b, const char *path,
+static void write_filename_items(struct para_buffer *b, const char *path,
 		unsigned flags)
 {
 	char *val;
-	int ret;
 
-	if (!(flags & LS_FLAG_FULL_PATH))
-		return WRITE_STATUS_ITEM(b, SI_BASENAME, "%s\n", path);
-	ret = WRITE_STATUS_ITEM(b, SI_PATH, "%s\n", path);
-	if (ret < 0)
-		return ret;
+	if (!(flags & LS_FLAG_FULL_PATH)) {
+		WRITE_STATUS_ITEM(b, SI_BASENAME, "%s\n", path);
+		return;
+	}
+	WRITE_STATUS_ITEM(b, SI_PATH, "%s\n", path);
 	val = para_basename(path);
-	ret = WRITE_STATUS_ITEM(b, SI_BASENAME, "%s\n", val? val : "");
-	if (ret < 0)
-		return ret;
+	WRITE_STATUS_ITEM(b, SI_BASENAME, "%s\n", val? val : "");
 	val = para_dirname(path);
-	ret = WRITE_STATUS_ITEM(b, SI_DIRECTORY, "%s\n", val? val : "");
+	WRITE_STATUS_ITEM(b, SI_DIRECTORY, "%s\n", val? val : "");
 	free(val);
-	return ret;
 }
 
 static int print_chunk_table(struct ls_data *d, struct para_buffer *b)
@@ -820,32 +813,27 @@ static int print_chunk_table(struct ls_data *d, struct para_buffer *b)
 		AFTCOL_CHUNKS, &chunk_table_obj));
 	if (ret < 0)
 		return ret;
-	ret = para_printf(b, "%s\n"
+	para_printf(b, "%s\n"
 		"chunk_time: %lu:%lu\nchunk_offsets: ",
 		d->path,
 		(long unsigned) d->afhi.chunk_tv.tv_sec,
 		(long unsigned) d->afhi.chunk_tv.tv_usec
 	);
-	if (ret < 0)
-		goto out;
 	buf = chunk_table_obj.data;
-	for (i = 0; i <= d->afhi.chunks_total; i++) {
-		ret = para_printf(b, "%u ", (unsigned) read_u32(buf + 4 * i));
-		if (ret < 0)
-			goto out;
-	}
-	ret = para_printf(b, "\n");
-out:
+	for (i = 0; i <= d->afhi.chunks_total; i++)
+		para_printf(b, "%u ", (unsigned) read_u32(buf + 4 * i));
+	para_printf(b, "\n");
+	ret = 1;
 	osl_close_disk_object(&chunk_table_obj);
 	return ret;
 }
 
-static int write_score(struct para_buffer *b, struct ls_data *d,
+static void write_score(struct para_buffer *b, struct ls_data *d,
 		struct ls_options *opts)
 {
 	if (!(opts->flags & LS_FLAG_ADMISSIBLE_ONLY)) /* no score*/
-		return 0;
-	return WRITE_STATUS_ITEM(b, SI_SCORE, "%li\n", d->score);
+		return;
+	WRITE_STATUS_ITEM(b, SI_SCORE, "%li\n", d->score);
 }
 
 static int print_list_item(struct ls_data *d, struct ls_options *opts,
@@ -860,7 +848,8 @@ static int print_list_item(struct ls_data *d, struct ls_options *opts,
 	char asc_hash[2 * HASH_SIZE + 1];
 
 	if (opts->mode == LS_MODE_SHORT) {
-		ret = para_printf(b, "%s\n", d->path);
+		para_printf(b, "%s\n", d->path);
+		ret = 1;
 		goto out;
 	}
 	if (opts->mode == LS_MODE_CHUNKS) {
@@ -881,12 +870,10 @@ static int print_list_item(struct ls_data *d, struct ls_options *opts,
 	if (opts->mode == LS_MODE_LONG) {
 		struct ls_widths *w = &opts->widths;
 		if (opts->flags & LS_FLAG_ADMISSIBLE_ONLY) {
-			ret = para_printf(b, "%*li ",
-				opts->widths.score_width, d->score);
-			if (ret < 0)
-				goto out;
+			para_printf(b, "%*li ", opts->widths.score_width,
+				d->score);
 		}
-		ret = para_printf(b,
+		para_printf(b,
 			"%s "   /* attributes */
 			"%*u "  /* amp */
 			"%*d "  /* image_id  */
@@ -913,98 +900,52 @@ static int print_list_item(struct ls_data *d, struct ls_options *opts,
 			last_played_time,
 			d->path
 		);
+		ret = 1;
 		goto out;
 	}
 	if (opts->mode == LS_MODE_MBOX) {
 		const char *bn = para_basename(d->path);
-		ret = para_printf(b,
+		para_printf(b,
 			"From foo@localhost %s\n"
 			"Received: from\nTo: bar\nFrom: a\n"
 			"Subject: %s\n\n",
 			last_played_time,
 			bn? bn : "?");
-		if (ret < 0)
-			goto out;
 	}
-	ret = write_filename_items(b, d->path, opts->flags);
-	if (ret < 0)
-		goto out;
-	ret = write_score(b, d, opts);
-	if (ret < 0)
-		goto out;
+	write_filename_items(b, d->path, opts->flags);
+	write_score(b, d, opts);
 	ret = write_attribute_items(b, att_buf, afsi);
 	if (ret < 0)
 		goto out;
-	ret = write_image_items(b, afsi);
-	if (ret < 0)
-		goto out;
-	ret = write_lyrics_items(b, afsi);
-	if (ret < 0)
-		goto out;
+	write_image_items(b, afsi);
+	write_lyrics_items(b, afsi);
 	hash_to_asc(d->hash, asc_hash);
-	ret = WRITE_STATUS_ITEM(b, SI_HASH, "%s\n", asc_hash);
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_BITRATE, "%dkbit/s\n", afhi->bitrate);
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_FORMAT, "%s\n",
+	WRITE_STATUS_ITEM(b, SI_HASH, "%s\n", asc_hash);
+	WRITE_STATUS_ITEM(b, SI_BITRATE, "%dkbit/s\n", afhi->bitrate);
+	WRITE_STATUS_ITEM(b, SI_FORMAT, "%s\n",
 		audio_format_name(afsi->audio_format_id));
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_FREQUENCY, "%dHz\n", afhi->frequency);
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_CHANNELS, "%d\n", afhi->channels);
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_DURATION, "%s\n", duration_buf);
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_SECONDS_TOTAL, "%lu\n",
+	WRITE_STATUS_ITEM(b, SI_FREQUENCY, "%dHz\n", afhi->frequency);
+	WRITE_STATUS_ITEM(b, SI_CHANNELS, "%d\n", afhi->channels);
+	WRITE_STATUS_ITEM(b, SI_DURATION, "%s\n", duration_buf);
+	WRITE_STATUS_ITEM(b, SI_SECONDS_TOTAL, "%" PRIu32 "\n",
 		afhi->seconds_total);
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_LAST_PLAYED, "%s\n", last_played_time);
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_NUM_PLAYED, "%d\n", afsi->num_played);
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_AMPLIFICATION, "%u\n", afsi->amp);
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_CHUNK_TIME, "%lu\n",
-		tv2ms(&afhi->chunk_tv));
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_NUM_CHUNKS, "%lu\n",
+	WRITE_STATUS_ITEM(b, SI_LAST_PLAYED, "%s\n", last_played_time);
+	WRITE_STATUS_ITEM(b, SI_NUM_PLAYED, "%d\n", afsi->num_played);
+	WRITE_STATUS_ITEM(b, SI_AMPLIFICATION, "%u\n", afsi->amp);
+	WRITE_STATUS_ITEM(b, SI_CHUNK_TIME, "%lu\n", tv2ms(&afhi->chunk_tv));
+	WRITE_STATUS_ITEM(b, SI_NUM_CHUNKS, "%" PRIu32 "\n",
 		afhi->chunks_total);
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_TECHINFO, "%s\n", afhi->techinfo);
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_ARTIST, "%s\n", afhi->tags.artist);
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_TITLE, "%s\n", afhi->tags.title);
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_YEAR, "%s\n", afhi->tags.year);
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_ALBUM, "%s\n", afhi->tags.album);
-	if (ret < 0)
-		goto out;
-	ret = WRITE_STATUS_ITEM(b, SI_COMMENT, "%s\n", afhi->tags.comment);
-	if (ret < 0)
-		goto out;
+	WRITE_STATUS_ITEM(b, SI_TECHINFO, "%s\n", afhi->techinfo);
+	WRITE_STATUS_ITEM(b, SI_ARTIST, "%s\n", afhi->tags.artist);
+	WRITE_STATUS_ITEM(b, SI_TITLE, "%s\n", afhi->tags.title);
+	WRITE_STATUS_ITEM(b, SI_YEAR, "%s\n", afhi->tags.year);
+	WRITE_STATUS_ITEM(b, SI_ALBUM, "%s\n", afhi->tags.album);
+	WRITE_STATUS_ITEM(b, SI_COMMENT, "%s\n", afhi->tags.comment);
 	if (opts->mode == LS_MODE_MBOX) {
 		struct osl_object lyrics_def;
 		lyr_get_def_by_id(afsi->lyrics_id, &lyrics_def);
 		if (lyrics_def.data) {
-			ret = para_printf(b, "Lyrics:\n~~~~~~~\n%s",
+			para_printf(b, "Lyrics:\n~~~~~~~\n%s",
 				(char *)lyrics_def.data);
 			osl_close_disk_object(&lyrics_def);
 		}
@@ -1033,9 +974,8 @@ static void make_inode_status_items(struct para_buffer *pb)
 	ret = strftime(mtime_str, 29, "%b %d %Y", &mtime_tm);
 	assert(ret > 0); /* number of bytes placed in mtime_str */
 out:
-	/* We don't care too much about errors here */
-	(void)WRITE_STATUS_ITEM(pb, SI_MTIME, "%s\n", mtime_str);
-	(void)WRITE_STATUS_ITEM(pb, SI_FILE_SIZE, "%ld\n", statbuf.st_size / 1024);
+	WRITE_STATUS_ITEM(pb, SI_MTIME, "%s\n", mtime_str);
+	WRITE_STATUS_ITEM(pb, SI_FILE_SIZE, "%ld\n", statbuf.st_size / 1024);
 }
 
 static int make_status_items(void)
@@ -1139,7 +1079,9 @@ again:
 	 * No need to update the status items as the AFSI_CHANGE event will
 	 * recreate them.
 	 */
-	afs_event(AFSI_CHANGE, NULL, &aced);
+	ret = afs_event(AFSI_CHANGE, NULL, &aced);
+	if (ret < 0)
+		goto out;
 	ret = save_afd(afd);
 out:
 	free(afd->afhi.chunk_table);
@@ -1358,22 +1300,14 @@ err:
 	return ret;
 }
 
-static void com_ls_callback(int fd, const struct osl_object *query)
+static int com_ls_callback(struct afs_callback_arg *aca)
 {
-	struct ls_options *opts = query->data;
-	char *p, *pattern_start = (char *)query->data + sizeof(*opts);
-	struct para_buffer b = {
-		.max_size = shm_get_shmmax(),
-		.flags = (opts->mode == LS_MODE_PARSER)? PBF_SIZE_PREFIX : 0,
-		.max_size_handler = afs_max_size_handler,
-		.private_data = &(struct afs_max_size_handler_data) {
-			.fd = fd,
-			.band = SBD_OUTPUT
-		}
-	};
+	struct ls_options *opts = aca->query.data;
+	char *p, *pattern_start = (char *)aca->query.data + sizeof(*opts);
 	int i = 0, ret;
 	time_t current_time;
 
+	aca->pbout.flags = (opts->mode == LS_MODE_PARSER)? PBF_SIZE_PREFIX : 0;
 	if (opts->num_patterns) {
 		opts->patterns = para_malloc(opts->num_patterns * sizeof(char *));
 		for (i = 0, p = pattern_start; i < opts->num_patterns; i++) {
@@ -1390,8 +1324,7 @@ static void com_ls_callback(int fd, const struct osl_object *query)
 	if (ret < 0)
 		goto out;
 	if (opts->num_matching_paths == 0) {
-		if (opts->num_patterns > 0)
-			para_printf(&b, "no matches\n");
+		ret = opts->num_patterns > 0? -E_NO_MATCH : 0;
 		goto out;
 	}
 	ret = sort_matching_paths(opts);
@@ -1400,23 +1333,23 @@ static void com_ls_callback(int fd, const struct osl_object *query)
 	time(&current_time);
 	if (opts->flags & LS_FLAG_REVERSE)
 		for (i = opts->num_matching_paths - 1; i >= 0; i--) {
-			ret = print_list_item(opts->data_ptr[i], opts, &b, current_time);
+			ret = print_list_item(opts->data_ptr[i], opts,
+				&aca->pbout, current_time);
 			if (ret < 0)
 				goto out;
 		}
 	else
 		for (i = 0; i < opts->num_matching_paths; i++) {
-			ret = print_list_item(opts->data_ptr[i], opts, &b, current_time);
+			ret = print_list_item(opts->data_ptr[i], opts,
+				&aca->pbout, current_time);
 			if (ret < 0)
 				goto out;
 		}
 out:
-	if (b.offset)
-		pass_buffer_as_shm(fd, SBD_OUTPUT, b.buf, b.offset);
-	free(b.buf);
 	free(opts->data);
 	free(opts->data_ptr);
 	free(opts->patterns);
+	return ret;
 }
 
 /*
@@ -1424,7 +1357,7 @@ out:
  */
 int com_ls(struct command_context *cc)
 {
-	int i, ret;
+	int i;
 	unsigned flags = 0;
 	enum ls_sorting_method sort = LS_SORT_BY_PATH;
 	enum ls_listing_mode mode = LS_MODE_SHORT;
@@ -1439,18 +1372,26 @@ int com_ls(struct command_context *cc)
 			i++;
 			break;
 		}
+		/*
+		 * Compatibility: Prior to 0.5.5 it was necessary to specify
+		 * the listing mode without the '=' character as in -lv, for
+		 * example. Now the variant with '=' is preferred and
+		 * documented but we still accept the old way to specify the
+		 * listing mode.
+		 *
+		 * Support for the legacy syntax can be dropped at 0.6.0
+		 * or later.
+		 */
 		if (!strncmp(arg, "-l", 2)) {
-			if (!*(arg + 2)) {
-				mode = LS_MODE_LONG;
-				continue;
-			}
-			if (*(arg + 3))
-				return -E_AFT_SYNTAX;
-			switch(*(arg + 2)) {
+			arg += 2;
+			if (*arg == '=')
+				arg++;
+			switch (*arg) {
 			case 's':
 				mode = LS_MODE_SHORT;
 				continue;
 			case 'l':
+			case '\0':
 				mode = LS_MODE_LONG;
 				continue;
 			case 'v':
@@ -1485,10 +1426,12 @@ int com_ls(struct command_context *cc)
 			flags |= LS_FLAG_UNIXDATE;
 			continue;
 		}
+		/* The compatibility remark above applies also to -s. */
 		if (!strncmp(arg, "-s", 2)) {
-			if (!*(arg + 2) || *(arg + 3))
-				return -E_AFT_SYNTAX;
-			switch(*(arg + 2)) {
+			arg += 2;
+			if (*arg == '=')
+				arg++;
+			switch (*arg) {
 			case 'p':
 				sort = LS_SORT_BY_PATH;
 				continue;
@@ -1533,9 +1476,8 @@ int com_ls(struct command_context *cc)
 	opts.sorting = sort;
 	opts.mode = mode;
 	opts.num_patterns = cc->argc - i;
-	ret = send_option_arg_callback_request(&query, opts.num_patterns,
+	return send_option_arg_callback_request(&query, opts.num_patterns,
 		cc->argv + i, com_ls_callback, afs_cb_result_handler, cc);
-	return ret;
 }
 
 /**
@@ -1552,27 +1494,36 @@ int audio_file_loop(void *private_data, osl_rbtree_loop_func *func)
 		func));
 }
 
-static struct osl_row *find_hash_sister(unsigned char *hash)
+static int find_hash_sister(unsigned char *hash, struct osl_row **result)
 {
-	const struct osl_object obj = {.data = hash, .size = HASH_SIZE};
-	struct osl_row *row;
+	int ret = aft_get_row_of_hash(hash, result);
 
-	osl_get_row(audio_file_table, AFTCOL_HASH, &obj, &row);
-	return row;
+	if (ret == -OSL_ERRNO_TO_PARA_ERROR(E_OSL_RB_KEY_NOT_FOUND))
+		return 0;
+	return ret;
+}
+
+static int find_path_brother(const char *path, struct osl_row **result)
+{
+	int ret = aft_get_row_of_path(path, result);
+
+	if (ret == -OSL_ERRNO_TO_PARA_ERROR(E_OSL_RB_KEY_NOT_FOUND))
+		return 0;
+	return ret;
 }
 
 /** The format of the data stored by save_audio_file_data(). */
 enum com_add_buffer_offsets {
-	/** afhi (if present) starts here. */
+	/* afhi (if present) starts at this offset. */
 	CAB_AFHI_OFFSET_POS = 0,
 	/** Start of the chunk table (if present). */
-	CAB_CHUNKS_OFFSET_POS = 2,
-	/** Audio format id. */
-	CAB_AUDIO_FORMAT_OFFSET = 4,
+	CAB_CHUNKS_OFFSET_POS = 4,
 	/** Flags given to the add command. */
-	CAB_FLAGS_OFFSET = 5,
+	CAB_FLAGS_OFFSET = 8,
+	/** Audio format id. */
+	CAB_AUDIO_FORMAT_ID_OFFSET = 12,
 	/** The hash of the audio file being added. */
-	CAB_HASH_OFFSET = 9,
+	CAB_HASH_OFFSET = 13,
 	/** Start of the path of the audio file. */
 	CAB_PATH_OFFSET = (CAB_HASH_OFFSET + HASH_SIZE),
 };
@@ -1593,27 +1544,23 @@ static void save_add_callback_buffer(unsigned char *hash, const char *path,
 	size_t size = CAB_PATH_OFFSET + path_len + afhi_size
 		+ sizeof_chunk_table(afhi);
 	char *buf = para_malloc(size);
-	uint16_t pos;
-
-	write_u8(buf + CAB_AUDIO_FORMAT_OFFSET, audio_format_num);
-	write_u32(buf + CAB_FLAGS_OFFSET, flags);
-
-	memcpy(buf + CAB_HASH_OFFSET, hash, HASH_SIZE);
-	strcpy(buf + CAB_PATH_OFFSET, path);
+	uint32_t pos;
 
 	pos = CAB_PATH_OFFSET + path_len;
-	PARA_DEBUG_LOG("size: %zu, afhi starts at %d\n", size, pos);
-	PARA_DEBUG_LOG("last afhi byte: %p, pos %zu\n", buf + pos + afhi_size - 1,
-		pos + afhi_size - 1);
-	write_u16(buf + CAB_AFHI_OFFSET_POS, pos);
+	write_u32(buf + CAB_AFHI_OFFSET_POS, pos);
 	save_afhi(afhi, buf + pos);
-
 	pos += afhi_size;
-	PARA_DEBUG_LOG("size: %zu, chunks start at %d\n", size, pos);
-	write_u16(buf + CAB_CHUNKS_OFFSET_POS, pos);
+
+	write_u32(buf + CAB_CHUNKS_OFFSET_POS, pos);
 	if (afhi)
 		save_chunk_table(afhi, buf + pos);
-	PARA_DEBUG_LOG("last byte in buf: %p\n", buf + size - 1);
+
+	write_u32(buf + CAB_FLAGS_OFFSET, flags);
+	write_u8(buf + CAB_AUDIO_FORMAT_ID_OFFSET, audio_format_num);
+
+	memcpy(buf + CAB_HASH_OFFSET, hash, HASH_SIZE);
+	strcpy(buf + CAB_PATH_OFFSET, path);
+
 	obj->data = buf;
 	obj->size = size;
 }
@@ -1681,9 +1628,9 @@ enum com_add_flags {
 	ADD_FLAG_ALL = 8,
 };
 
-static void com_add_callback(int fd, const struct osl_object *query)
+static int com_add_callback(struct afs_callback_arg *aca)
 {
-	char *buf = query->data, *path;
+	char *buf = aca->query.data, *path;
 	struct osl_row *pb, *aft_row;
 	struct osl_row *hs;
 	struct osl_object objs[NUM_AFT_COLUMNS];
@@ -1693,14 +1640,6 @@ static void com_add_callback(int fd, const struct osl_object *query)
 	char afsi_buf[AFSI_SIZE];
 	uint32_t flags = read_u32(buf + CAB_FLAGS_OFFSET);
 	struct afs_info default_afsi = {.last_played = 0};
-	struct para_buffer msg = {
-		.max_size = shm_get_shmmax(),
-		.max_size_handler = afs_max_size_handler,
-		.private_data = &(struct afs_max_size_handler_data) {
-			.fd = fd,
-			.band = SBD_OUTPUT
-		}
-	};
 	uint16_t afhi_offset, chunks_offset;
 
 	hash = (unsigned char *)buf + CAB_HASH_OFFSET;
@@ -1713,26 +1652,26 @@ static void com_add_callback(int fd, const struct osl_object *query)
 	objs[AFTCOL_PATH].size = strlen(path) + 1;
 
 	PARA_INFO_LOG("request to add %s\n", path);
-	hs = find_hash_sister(hash);
-	ret = aft_get_row_of_path(path, &pb);
-	if (ret < 0 && ret != -OSL_ERRNO_TO_PARA_ERROR(E_OSL_RB_KEY_NOT_FOUND))
+	ret = find_hash_sister(hash, &hs);
+	if (ret < 0)
+		goto out;
+	ret = find_path_brother(path, &pb);
+	if (ret < 0)
 		goto out;
 	if (hs && pb && hs == pb && !(flags & ADD_FLAG_FORCE)) {
 		if (flags & ADD_FLAG_VERBOSE)
-			ret = para_printf(&msg, "ignoring duplicate\n");
-		else
-			ret = 1;
+			para_printf(&aca->pbout, "ignoring duplicate\n");
+		ret = 1;
 		goto out;
 	}
 	if (hs && hs != pb) {
 		struct osl_object obj;
 		if (pb) { /* hs trumps pb, remove pb */
-			if (flags & ADD_FLAG_VERBOSE) {
-				ret = para_printf(&msg, "removing %s\n", path);
-				if (ret < 0)
-					goto out;
-			}
-			afs_event(AUDIO_FILE_REMOVE, &msg, pb);
+			if (flags & ADD_FLAG_VERBOSE)
+				para_printf(&aca->pbout, "removing %s\n", path);
+			ret = afs_event(AUDIO_FILE_REMOVE, &aca->pbout, pb);
+			if (ret < 0)
+				goto out;
 			ret = osl(osl_del_row(audio_file_table, pb));
 			if (ret < 0)
 				goto out;
@@ -1744,21 +1683,22 @@ static void com_add_callback(int fd, const struct osl_object *query)
 				AFTCOL_PATH, &obj));
 			if (ret < 0)
 				goto out;
-			ret = para_printf(&msg, "renamed from %s\n", (char *)obj.data);
-			if (ret < 0)
-				goto out;
+			para_printf(&aca->pbout, "renamed from %s\n",
+				(char *)obj.data);
 		}
 		ret = osl(osl_update_object(audio_file_table, hs, AFTCOL_PATH,
 			&objs[AFTCOL_PATH]));
 		if (ret < 0)
 			goto out;
-		afs_event(AUDIO_FILE_RENAME, &msg, hs);
+		ret = afs_event(AUDIO_FILE_RENAME, &aca->pbout, hs);
+		if (ret < 0)
+			goto out;
 		if (!(flags & ADD_FLAG_FORCE))
 			goto out;
 	}
 	/* no hs or force mode, child must have sent afhi */
-	afhi_offset = read_u16(buf + CAB_AFHI_OFFSET_POS);
-	chunks_offset = read_u16(buf + CAB_CHUNKS_OFFSET_POS);
+	afhi_offset = read_u32(buf + CAB_AFHI_OFFSET_POS);
+	chunks_offset = read_u32(buf + CAB_CHUNKS_OFFSET_POS);
 
 	objs[AFTCOL_AFHI].data = buf + afhi_offset;
 	objs[AFTCOL_AFHI].size = chunks_offset - afhi_offset;
@@ -1766,7 +1706,7 @@ static void com_add_callback(int fd, const struct osl_object *query)
 	if (!objs[AFTCOL_AFHI].size) /* "impossible" */
 		goto out;
 	objs[AFTCOL_CHUNKS].data = buf + chunks_offset;
-	objs[AFTCOL_CHUNKS].size = query->size - chunks_offset;
+	objs[AFTCOL_CHUNKS].size = aca->query.size - chunks_offset;
 	if (pb && !hs) { /* update pb's hash */
 		char old_asc[2 * HASH_SIZE + 1];
 		unsigned char *old_hash;
@@ -1774,12 +1714,9 @@ static void com_add_callback(int fd, const struct osl_object *query)
 		if (ret < 0)
 			goto out;
 		hash_to_asc(old_hash, old_asc);
-		if (flags & ADD_FLAG_VERBOSE) {
-			ret = para_printf(&msg, "file change: %s -> %s\n",
+		if (flags & ADD_FLAG_VERBOSE)
+			para_printf(&aca->pbout, "file change: %s -> %s\n",
 				old_asc, asc);
-			if (ret < 0)
-				goto out;
-		}
 		ret = osl_update_object(audio_file_table, pb, AFTCOL_HASH,
 			&objs[AFTCOL_HASH]);
 		if (ret < 0)
@@ -1788,11 +1725,9 @@ static void com_add_callback(int fd, const struct osl_object *query)
 	if (hs || pb) { /* (hs != NULL and pb != NULL) implies hs == pb */
 		struct osl_row *row = pb? pb : hs;
 		/* update afhi and chunk_table */
-		if (flags & ADD_FLAG_VERBOSE) {
-			ret = para_printf(&msg, "updating afhi and chunk table\n");
-			if (ret < 0)
-				goto out;
-		}
+		if (flags & ADD_FLAG_VERBOSE)
+			para_printf(&aca->pbout,
+				"updating afhi and chunk table\n");
 		ret = osl(osl_update_object(audio_file_table, row, AFTCOL_AFHI,
 			&objs[AFTCOL_AFHI]));
 		if (ret < 0)
@@ -1801,29 +1736,28 @@ static void com_add_callback(int fd, const struct osl_object *query)
 			&objs[AFTCOL_CHUNKS]));
 		if (ret < 0)
 			goto out;
-		afs_event(AFHI_CHANGE, &msg, row);
-		goto out;
-	}
-	/* new entry, use default afsi */
-	if (flags & ADD_FLAG_VERBOSE) {
-		ret = para_printf(&msg, "new file\n");
+		ret = afs_event(AFHI_CHANGE, &aca->pbout, row);
 		if (ret < 0)
 			goto out;
+		goto out;
 	}
+	/* new entry, use default afsi */
+	if (flags & ADD_FLAG_VERBOSE)
+		para_printf(&aca->pbout, "new file\n");
 	default_afsi.last_played = time(NULL) - 365 * 24 * 60 * 60;
-	default_afsi.audio_format_id = read_u8(buf + CAB_AUDIO_FORMAT_OFFSET);
+	default_afsi.audio_format_id = read_u8(buf + CAB_AUDIO_FORMAT_ID_OFFSET);
 
 	objs[AFTCOL_AFSI].data = &afsi_buf;
 	objs[AFTCOL_AFSI].size = AFSI_SIZE;
 	save_afsi(&default_afsi, &objs[AFTCOL_AFSI]);
 	ret = osl(osl_add_and_get_row(audio_file_table, objs, &aft_row));
-	afs_event(AUDIO_FILE_ADD, &msg, aft_row);
+	if (ret < 0)
+		goto out;
+	ret = afs_event(AUDIO_FILE_ADD, &aca->pbout, aft_row);
 out:
 	if (ret < 0)
-		para_printf(&msg, "%s\n", para_strerror(-ret));
-	if (msg.offset)
-		pass_buffer_as_shm(fd, SBD_OUTPUT, msg.buf, msg.offset);
-	free(msg.buf);
+		para_printf(&aca->pbout, "could not add %s\n", path);
+	return ret;
 }
 
 /** Used by com_add(). */
@@ -1834,26 +1768,26 @@ struct private_add_data {
 	uint32_t flags;
 };
 
-static void path_brother_callback(int fd, const struct osl_object *query)
+static int path_brother_callback(struct afs_callback_arg *aca)
 {
-	char *path = query->data;
+	char *path = aca->query.data;
 	struct osl_row *path_brother;
-	int ret = aft_get_row_of_path(path, &path_brother);
-	if (ret < 0)
-		return;
-	pass_buffer_as_shm(fd, SBD_OUTPUT, (char *)&path_brother,
+	int ret = find_path_brother(path, &path_brother);
+	if (ret <= 0)
+		return ret;
+	return pass_buffer_as_shm(aca->fd, SBD_OUTPUT, (char *)&path_brother,
 		sizeof(path_brother));
 }
 
-static void hash_sister_callback(int fd, const struct osl_object *query)
+static int hash_sister_callback(struct afs_callback_arg *aca)
 {
-	unsigned char *hash = query->data;
+	unsigned char *hash = aca->query.data;
 	struct osl_row *hash_sister;
+	int ret = find_hash_sister(hash, &hash_sister);
 
-	hash_sister = find_hash_sister(hash);
-	if (!hash_sister)
-		return;
-	pass_buffer_as_shm(fd, SBD_OUTPUT, (char *)&hash_sister,
+	if (ret <= 0)
+		return ret;
+	return pass_buffer_as_shm(aca->fd, SBD_OUTPUT, (char *)&hash_sister,
 		sizeof(hash_sister));
 }
 
@@ -1861,7 +1795,9 @@ static int get_row_pointer_from_result(struct osl_object *result,
 		__a_unused uint8_t band, void *private)
 {
 	struct osl_row **row = private;
-	*row = *(struct osl_row **)(result->data);
+
+	if (band == SBD_OUTPUT)
+		*row = *(struct osl_row **)(result->data);
 	return 1;
 }
 
@@ -2038,97 +1974,78 @@ struct com_touch_options {
 	unsigned flags;
 };
 
-/** Data passed to the action handler of com_touch(). */
-struct touch_action_data {
-	/** Command line options (see \ref com_touch_options). */
-	struct com_touch_options *cto;
-	/** Message buffer. */
-	struct para_buffer pb;
-};
-
 static int touch_audio_file(__a_unused struct osl_table *table,
 		struct osl_row *row, const char *name, void *data)
 {
-	struct touch_action_data *tad = data;
+	struct afs_callback_arg *aca = data;
+	struct com_touch_options *cto = aca->query.data;
 	struct osl_object obj;
 	struct afs_info old_afsi, new_afsi;
-	int ret, no_options = tad->cto->num_played < 0 && tad->cto->last_played < 0 &&
-		tad->cto->lyrics_id < 0 && tad->cto->image_id < 0 && tad->cto->amp < 0;
+	int ret, no_options = cto->num_played < 0 && cto->last_played < 0 &&
+		cto->lyrics_id < 0 && cto->image_id < 0 && cto->amp < 0;
 	struct afsi_change_event_data aced;
 
 	ret = get_afsi_object_of_row(row, &obj);
-	if (ret < 0)
-		return para_printf(&tad->pb, "%s: %s\n", name, para_strerror(-ret));
+	if (ret < 0) {
+		para_printf(&aca->pbout, "cannot touch %s\n", name);
+		return ret;
+	}
 	ret = load_afsi(&old_afsi, &obj);
-	if (ret < 0)
-		return para_printf(&tad->pb, "%s: %s\n", name, para_strerror(-ret));
+	if (ret < 0) {
+		para_printf(&aca->pbout, "cannot touch %s\n", name);
+		return ret;
+	}
 	new_afsi = old_afsi;
 	if (no_options) {
 		new_afsi.num_played++;
 		new_afsi.last_played = time(NULL);
-		if (tad->cto->flags & TOUCH_FLAG_VERBOSE) {
-			ret = para_printf(&tad->pb, "%s: num_played = %u, "
+		if (cto->flags & TOUCH_FLAG_VERBOSE)
+			para_printf(&aca->pbout, "%s: num_played = %u, "
 				"last_played = now()\n", name,
 				new_afsi.num_played);
-			if (ret < 0)
-				return ret;
-		}
 	} else {
-		if (tad->cto->flags & TOUCH_FLAG_VERBOSE) {
-			ret = para_printf(&tad->pb, "touching %s\n", name);
-			if (ret < 0)
-				return ret;
-		}
-		if (tad->cto->lyrics_id >= 0)
-			new_afsi.lyrics_id = tad->cto->lyrics_id;
-		if (tad->cto->image_id >= 0)
-			new_afsi.image_id = tad->cto->image_id;
-		if (tad->cto->num_played >= 0)
-			new_afsi.num_played = tad->cto->num_played;
-		if (tad->cto->last_played >= 0)
-			new_afsi.last_played = tad->cto->last_played;
-		if (tad->cto->amp >= 0)
-			new_afsi.amp = tad->cto->amp;
+		if (cto->flags & TOUCH_FLAG_VERBOSE)
+			para_printf(&aca->pbout, "touching %s\n", name);
+		if (cto->lyrics_id >= 0)
+			new_afsi.lyrics_id = cto->lyrics_id;
+		if (cto->image_id >= 0)
+			new_afsi.image_id = cto->image_id;
+		if (cto->num_played >= 0)
+			new_afsi.num_played = cto->num_played;
+		if (cto->last_played >= 0)
+			new_afsi.last_played = cto->last_played;
+		if (cto->amp >= 0)
+			new_afsi.amp = cto->amp;
 	}
 	save_afsi(&new_afsi, &obj); /* in-place update */
 	aced.aft_row = row;
 	aced.old_afsi = &old_afsi;
-	afs_event(AFSI_CHANGE, &tad->pb, &aced);
-	return 1;
+	return afs_event(AFSI_CHANGE, &aca->pbout, &aced);
 }
 
-static void com_touch_callback(int fd, const struct osl_object *query)
+static int com_touch_callback(struct afs_callback_arg *aca)
 {
-	struct touch_action_data tad = {.cto = query->data,
-		.pb = {
-			.max_size = shm_get_shmmax(),
-			.private_data = &(struct afs_max_size_handler_data) {
-				.fd = fd,
-				.band = SBD_OUTPUT
-			},
-			.max_size_handler = afs_max_size_handler
-		}
-	};
-	int ret, ret2 = 0;
+	int ret;
+	struct com_touch_options *cto = aca->query.data;
 	struct pattern_match_data pmd = {
 		.table = audio_file_table,
 		.loop_col_num = AFTCOL_HASH,
 		.match_col_num = AFTCOL_PATH,
-		.patterns = {.data = (char *)query->data + sizeof(*tad.cto),
-			.size = query->size - sizeof(*tad.cto)},
-		.data = &tad,
+		.patterns = {
+			.data = (char *)aca->query.data
+				+ sizeof(struct com_touch_options),
+			.size = aca->query.size
+				- sizeof(struct com_touch_options)
+		},
+		.data = aca,
 		.action = touch_audio_file
 	};
-	if (tad.cto->flags & TOUCH_FLAG_FNM_PATHNAME)
+	if (cto->flags & TOUCH_FLAG_FNM_PATHNAME)
 		pmd.fnmatch_flags |= FNM_PATHNAME;
 	ret = for_each_matching_row(&pmd);
-	if (ret < 0)
-		ret2 = para_printf(&tad.pb, "%s\n", para_strerror(-ret));
-	else if (pmd.num_matches == 0)
-		ret2 = para_printf(&tad.pb, "no matches\n");
-	if (ret2 >= 0 && tad.pb.offset)
-		pass_buffer_as_shm(fd, SBD_OUTPUT, tad.pb.buf, tad.pb.offset);
-	free(tad.pb.buf);
+	if (ret >= 0 && pmd.num_matches == 0)
+		ret = -E_NO_MATCH;
+	return ret;
 }
 
 int com_touch(struct command_context *cc)
@@ -2198,11 +2115,8 @@ int com_touch(struct command_context *cc)
 	}
 	if (i >= cc->argc)
 		return -E_AFT_SYNTAX;
-	ret = send_option_arg_callback_request(&query, cc->argc - i,
+	return send_option_arg_callback_request(&query, cc->argc - i,
 		cc->argv + i, com_touch_callback, afs_cb_result_handler, cc);
-	if (ret < 0)
-		send_strerror(cc, -ret);
-	return ret;
 }
 
 /** Flags for com_rm(). */
@@ -2215,70 +2129,50 @@ enum rm_flags {
 	RM_FLAG_FNM_PATHNAME = 4
 };
 
-/** Data passed to the action handler of com_rm(). */
-struct com_rm_action_data {
-	/** Command line flags ((see \ref rm_flags). */
-	uint32_t flags;
-	/** Message buffer. */
-	struct para_buffer pb;
-};
-
 static int remove_audio_file(__a_unused struct osl_table *table,
 		struct osl_row *row, const char *name, void *data)
 {
-	struct com_rm_action_data *crd = data;
+	struct afs_callback_arg *aca = data;
+	uint32_t flags =*(uint32_t *)aca->query.data;
 	int ret;
 
-	if (crd->flags & RM_FLAG_VERBOSE) {
-		ret = para_printf(&crd->pb, "removing %s\n", name);
-		if (ret < 0)
-			return ret;
-	}
-	afs_event(AUDIO_FILE_REMOVE, &crd->pb, row);
+	if (flags & RM_FLAG_VERBOSE)
+		para_printf(&aca->pbout, "removing %s\n", name);
+	ret = afs_event(AUDIO_FILE_REMOVE, &aca->pbout, row);
+	if (ret < 0)
+		return ret;
 	ret = osl(osl_del_row(audio_file_table, row));
 	if (ret < 0)
-		para_printf(&crd->pb, "%s: %s\n", name, para_strerror(-ret));
+		para_printf(&aca->pbout, "cannot remove %s\n", name);
 	return ret;
 }
 
-static void com_rm_callback(int fd, const struct osl_object *query)
+static int com_rm_callback(struct afs_callback_arg *aca)
 {
-	struct com_rm_action_data crd = {.flags = *(uint32_t *)query->data,
-		.pb = {
-			.max_size = shm_get_shmmax(),
-			.private_data = &(struct afs_max_size_handler_data) {
-				.fd = fd,
-				.band = SBD_OUTPUT
-			},
-			.max_size_handler = afs_max_size_handler
-		}
-	};
 	int ret;
+	uint32_t flags = *(uint32_t *)aca->query.data;
 	struct pattern_match_data pmd = {
 		.table = audio_file_table,
 		.loop_col_num = AFTCOL_HASH,
 		.match_col_num = AFTCOL_PATH,
-		.patterns = {.data = (char *)query->data + sizeof(uint32_t),
-			.size = query->size - sizeof(uint32_t)},
-		.data = &crd,
+		.patterns = {.data = (char *)aca->query.data + sizeof(uint32_t),
+			.size = aca->query.size - sizeof(uint32_t)},
+		.data = aca,
 		.action = remove_audio_file
 	};
-	if (crd.flags & RM_FLAG_FNM_PATHNAME)
+	if (flags & RM_FLAG_FNM_PATHNAME)
 		pmd.fnmatch_flags |= FNM_PATHNAME;
 	ret = for_each_matching_row(&pmd);
-	if (ret < 0) {
-		para_printf(&crd.pb, "%s\n", para_strerror(-ret));
-		return;
-	}
-	if ((pmd.num_matches == 0) && !(crd.flags & RM_FLAG_FORCE))
-		ret = para_printf(&crd.pb, "no matches -- nothing removed\n");
-	else if (crd.flags & RM_FLAG_VERBOSE) {
-		ret = para_printf(&crd.pb, "removed %u files\n",
+	if (ret < 0)
+		goto out;
+	if (pmd.num_matches == 0) {
+		if (!(flags & RM_FLAG_FORCE))
+			ret = -E_NO_MATCH;
+	} else if (flags & RM_FLAG_VERBOSE)
+		para_printf(&aca->pbout, "removed %u file(s)\n",
 			pmd.num_matches);
-	}
-	if (ret >= 0 && crd.pb.offset)
-		pass_buffer_as_shm(fd, SBD_OUTPUT, crd.pb.buf, crd.pb.offset);
-	free(crd.pb.buf);
+out:
+	return ret;
 }
 
 /* TODO options: -r (recursive) */
@@ -2286,7 +2180,7 @@ int com_rm(struct command_context *cc)
 {
 	uint32_t flags = 0;
 	struct osl_object query = {.data = &flags, .size = sizeof(flags)};
-	int i, ret;
+	int i;
 
 	for (i = 1; i < cc->argc; i++) {
 		const char *arg = cc->argv[i];
@@ -2312,11 +2206,8 @@ int com_rm(struct command_context *cc)
 	}
 	if (i >= cc->argc)
 		return -E_AFT_SYNTAX;
-	ret = send_option_arg_callback_request(&query, cc->argc - i,
+	return send_option_arg_callback_request(&query, cc->argc - i,
 		cc->argv + i, com_rm_callback, afs_cb_result_handler, cc);
-	if (ret < 0)
-		send_strerror(cc, -ret);
-	return ret;
 }
 
 /**
@@ -2343,10 +2234,10 @@ enum cpsi_flags {
 struct cpsi_action_data {
 	/** command line flags (see \ref cpsi_flags). */
 	unsigned flags;
-	/** Message buffer. */
-	struct para_buffer pb;
 	/** Values are copied from here. */
 	struct afs_info source_afsi;
+	/** What was passed to com_cpsi_callback(). */
+	struct afs_callback_arg *aca;
 };
 
 static int copy_selector_info(__a_unused struct osl_table *table,
@@ -2374,38 +2265,27 @@ static int copy_selector_info(__a_unused struct osl_table *table,
 	if (cad->flags & CPSI_FLAG_COPY_ATTRIBUTES)
 		target_afsi.attributes = cad->source_afsi.attributes;
 	save_afsi(&target_afsi, &target_afsi_obj); /* in-place update */
-	if (cad->flags & CPSI_FLAG_VERBOSE) {
-		ret = para_printf(&cad->pb, "copied afsi to %s\n", name);
-		if (ret < 0)
-			return ret;
-	}
+	if (cad->flags & CPSI_FLAG_VERBOSE)
+		para_printf(&cad->aca->pbout, "copied afsi to %s\n", name);
 	aced.aft_row = row;
 	aced.old_afsi = &old_afsi;
-	afs_event(AFSI_CHANGE, &cad->pb, &aced);
-	return 1;
+	return afs_event(AFSI_CHANGE, &cad->aca->pbout, &aced);
 }
 
-static void com_cpsi_callback(int fd, const struct osl_object *query)
+static int com_cpsi_callback(struct afs_callback_arg *aca)
 {
 	struct cpsi_action_data cad = {
-		.flags = *(unsigned *)query->data,
-		.pb = {
-			.max_size = shm_get_shmmax(),
-			.private_data = &(struct afs_max_size_handler_data) {
-				.fd = fd,
-				.band = SBD_OUTPUT
-			},
-			.max_size_handler = afs_max_size_handler
-		}
+		.flags = *(unsigned *)aca->query.data,
+		.aca = aca
 	};
 	int ret;
-	char *source_path = (char *)query->data + sizeof(cad.flags);
+	char *source_path = (char *)aca->query.data + sizeof(cad.flags);
 	struct pattern_match_data pmd = {
 		.table = audio_file_table,
 		.loop_col_num = AFTCOL_HASH,
 		.match_col_num = AFTCOL_PATH,
 		.patterns = {.data = source_path + strlen(source_path) + 1,
-			.size = query->size - sizeof(cad.flags)
+			.size = aca->query.size - sizeof(cad.flags)
 				- strlen(source_path) - 1},
 		.data = &cad,
 		.action = copy_selector_info
@@ -2415,24 +2295,22 @@ static void com_cpsi_callback(int fd, const struct osl_object *query)
 	if (ret < 0)
 		goto out;
 	ret = for_each_matching_row(&pmd);
-out:
 	if (ret < 0)
-		para_printf(&cad.pb, "%s\n", para_strerror(-ret));
-	else if (pmd.num_matches > 0) {
+		goto out;
+	if (pmd.num_matches > 0) {
 		if (cad.flags & CPSI_FLAG_VERBOSE)
-			para_printf(&cad.pb, "copied requested afsi from %s "
-				"to %u files\n", source_path, pmd.num_matches);
+			para_printf(&aca->pbout, "updated afsi of %u file(s)\n",
+				pmd.num_matches);
 	} else
-		para_printf(&cad.pb, "no matches - nothing copied\n");
-	if (cad.pb.offset)
-		pass_buffer_as_shm(fd, SBD_OUTPUT, cad.pb.buf, cad.pb.offset);
-	free(cad.pb.buf);
+		ret = -E_NO_MATCH;
+out:
+	return ret;
 }
 
 int com_cpsi(struct command_context *cc)
 {
 	unsigned flags = 0;
-	int i, ret;
+	int i;
 	struct osl_object options = {.data = &flags, .size = sizeof(flags)};
 
 	for (i = 1; i < cc->argc; i++) {
@@ -2473,16 +2351,13 @@ int com_cpsi(struct command_context *cc)
 		return -E_AFT_SYNTAX;
 	if (!(flags & ~CPSI_FLAG_VERBOSE)) /* no copy flags given */
 		flags = ~(unsigned)CPSI_FLAG_VERBOSE | flags;
-	ret = send_option_arg_callback_request(&options, cc->argc - i,
+	return send_option_arg_callback_request(&options, cc->argc - i,
 		cc->argv + i, com_cpsi_callback, afs_cb_result_handler, cc);
-	if (ret < 0)
-		send_strerror(cc, -ret);
-	return ret;
 }
 
 struct change_atts_data {
 	uint64_t add_mask, del_mask;
-	struct para_buffer pb;
+	struct afs_callback_arg *aca;
 };
 
 static int change_atts(__a_unused struct osl_table *table,
@@ -2507,25 +2382,15 @@ static int change_atts(__a_unused struct osl_table *table,
 	new_afsi.attributes |= cad->add_mask;
 	new_afsi.attributes &= ~cad->del_mask;
 	save_afsi(&new_afsi, &obj); /* in-place update */
-	afs_event(AFSI_CHANGE, &cad->pb, &aced);
-	return 1;
+	return afs_event(AFSI_CHANGE, &cad->aca->pbout, &aced);
 }
 
-static void com_setatt_callback(int fd, const struct osl_object *query)
+static int com_setatt_callback(struct afs_callback_arg *aca)
 {
 	char *p;
 	int ret;
 	size_t len;
-	struct change_atts_data cad = {
-		.pb = {
-			.max_size = shm_get_shmmax(),
-			.max_size_handler = afs_max_size_handler,
-			.private_data = &(struct afs_max_size_handler_data) {
-				.fd = fd,
-				.band = SBD_OUTPUT
-			}
-		}
-	};
+	struct change_atts_data cad = {.aca = aca};
 	struct pattern_match_data pmd = {
 		.table = audio_file_table,
 		.loop_col_num = AFTCOL_HASH,
@@ -2535,9 +2400,14 @@ static void com_setatt_callback(int fd, const struct osl_object *query)
 		.action = change_atts
 	};
 
-	for (p = query->data; p < (char *)query->data + query->size; p += len + 1) {
+	for (
+		p = aca->query.data;
+		p < (char *)aca->query.data + aca->query.size;
+		p += len + 1
+	) {
 		char c;
 		unsigned char bitnum;
+		uint64_t one = 1;
 
 		len = strlen(p);
 		ret = -E_ATTR_SYNTAX;
@@ -2549,31 +2419,28 @@ static void com_setatt_callback(int fd, const struct osl_object *query)
 		p[len - 1] = '\0';
 		ret = get_attribute_bitnum_by_name(p, &bitnum);
 		if (ret < 0) {
-			para_printf(&cad.pb, "attribute not found: %s\n", p);
+			para_printf(&aca->pbout, "attribute not found: %s\n", p);
 			goto out;
 		}
 		if (c == '+')
-			cad.add_mask |= (1UL << bitnum);
+			cad.add_mask |= (one << bitnum);
 		else
-			cad.del_mask |= (1UL << bitnum);
+			cad.del_mask |= (one << bitnum);
 	}
 	ret = -E_ATTR_SYNTAX;
 	if (!cad.add_mask && !cad.del_mask)
 		goto out;
 	pmd.patterns.data = p;
-	assert(p < (char *)query->data + query->size);
-	pmd.patterns.size = (char *)query->data + query->size - p;
+	if (p >= (char *)aca->query.data + aca->query.size)
+		goto out;
+	pmd.patterns.size = (char *)aca->query.data + aca->query.size - p;
 	ret = for_each_matching_row(&pmd);
 	if (ret < 0)
 		goto out;
 	if (pmd.num_matches == 0)
-		para_printf(&cad.pb, "no matches\n");
+		ret = -E_NO_MATCH;
 out:
-	if (ret < 0)
-		para_printf(&cad.pb, "%s\n", para_strerror(-ret));
-	if (cad.pb.offset)
-		pass_buffer_as_shm(fd, SBD_OUTPUT, cad.pb.buf, cad.pb.offset);
-	free(cad.pb.buf);
+	return ret;
 }
 
 int com_setatt(struct command_context *cc)
@@ -2584,15 +2451,15 @@ int com_setatt(struct command_context *cc)
 		com_setatt_callback, afs_cb_result_handler, cc);
 }
 
-static void afs_stat_callback(int fd, const struct osl_object *query)
+static int afs_stat_callback(struct afs_callback_arg *aca)
 {
-	int *parser_friendly = query->data;
+	int *parser_friendly = aca->query.data;
 	char *buf = *parser_friendly?
 		parser_friendly_status_items : status_items;
 
 	if (!buf)
-		return;
-	pass_buffer_as_shm(fd, SBD_OUTPUT, buf, strlen(buf));
+		return 0;
+	return pass_buffer_as_shm(aca->fd, SBD_OUTPUT, buf, strlen(buf));
 }
 
 /**
@@ -2618,7 +2485,7 @@ int send_afs_status(struct command_context *cc, int parser_friendly)
 		afs_cb_result_handler, cc);
 }
 
-/* TODO: optionally fix problems by removing offending rows */
+/* returns success on non-fatal errors to keep the loop going */
 static int check_audio_file(struct osl_row *row, void *data)
 {
 	char *path;
@@ -2628,64 +2495,99 @@ static int check_audio_file(struct osl_row *row, void *data)
 	struct afs_info afsi;
 	char *blob_name;
 
-	if (ret < 0)
-		return para_printf(pb, "%s\n", para_strerror(-ret));
-	if (stat(path, &statbuf) < 0) {
-		ret = para_printf(pb, "%s: stat error (%s)\n", path, strerror(errno));
-		if (ret < 0)
-			return ret;
-	} else {
-		if (!S_ISREG(statbuf.st_mode)) {
-			ret = para_printf(pb, "%s: not a regular file\n", path);
-			if (ret < 0)
-				return ret;
-		}
+	if (ret < 0) {
+		para_printf(pb, "%s\n", para_strerror(-ret));
+		return ret;
 	}
+	if (stat(path, &statbuf) < 0)
+		para_printf(pb, "%s: stat error (%s)\n", path, strerror(errno));
+	else if (!S_ISREG(statbuf.st_mode))
+		para_printf(pb, "%s: not a regular file\n", path);
 	ret = get_afsi_of_row(row, &afsi);
-	if (ret < 0)
-		return para_printf(pb, "%s: %s\n", path, para_strerror(-ret));
-	ret = lyr_get_name_by_id(afsi.lyrics_id, &blob_name);
 	if (ret < 0) {
-		ret = para_printf(pb, "%s lyrics id %u: %s\n", path, afsi.lyrics_id,
-			para_strerror(-ret));
-		if (ret < 0)
-			return ret;
+		para_printf(pb, "%s: %s\n", path, para_strerror(-ret));
+		return 1;
 	}
+	ret = lyr_get_name_by_id(afsi.lyrics_id, &blob_name);
+	if (ret < 0)
+		para_printf(pb, "%s lyrics id %u: %s\n", path, afsi.lyrics_id,
+			para_strerror(-ret));
 	ret = img_get_name_by_id(afsi.image_id, &blob_name);
 	if (ret < 0)
-		ret = para_printf(pb, "%s image id %u: %s\n", path, afsi.image_id,
+		para_printf(pb, "%s image id %u: %s\n", path, afsi.image_id,
 			para_strerror(-ret));
-	return ret;
+	return 0;
 }
 
 /**
  * Check the audio file table for inconsistencies.
  *
- * \param fd The afs socket.
- * \param query Unused.
+ * \param aca Only ->pbout is used for diagnostics.
  *
- * This function always succeeds.
+ * \return Standard. Inconsistencies are reported but not regarded as an error.
  *
  * \sa com_check().
  */
-void aft_check_callback(int fd, __a_unused const struct osl_object *query)
+int aft_check_callback(struct afs_callback_arg *aca)
 {
-	struct para_buffer pb = {
-		.max_size = shm_get_shmmax(),
-		.private_data = &(struct afs_max_size_handler_data) {
-			.fd = fd,
-			.band = SBD_OUTPUT
-		},
-		.max_size_handler = afs_max_size_handler
-	};
-	int ret = para_printf(&pb, "checking audio file table...\n");
+	para_printf(&aca->pbout, "checking audio file table...\n");
+	return audio_file_loop(&aca->pbout, check_audio_file);
+}
 
-	if (ret < 0)
-		return;
-	audio_file_loop(&pb, check_audio_file);
-	if (pb.offset)
-		pass_buffer_as_shm(fd, SBD_OUTPUT, pb.buf, pb.offset);
-	free(pb.buf);
+struct aft_check_atts_data {
+	uint64_t att_mask;
+	struct para_buffer *pb;
+};
+
+static int check_atts_of_audio_file(struct osl_row *row, void *data)
+{
+	struct aft_check_atts_data *acad = data;
+	int ret;
+	struct afs_info afsi;
+	char *path;
+	uint64_t bad_bits;
+
+	ret = get_afsi_of_row(row, &afsi);
+	if (ret < 0) {
+		para_printf(acad->pb, "cannot get afsi\n");
+		return ret;
+	}
+	bad_bits = afsi.attributes & ~acad->att_mask;
+	if (bad_bits == 0) /* OK */
+		return 0;
+	ret = get_audio_file_path_of_row(row, &path);
+	if (ret < 0) {
+		para_printf(acad->pb, "cannot get path\n");
+		return ret;
+	}
+	para_printf(acad->pb, "invalid attribute bits (%" PRIu64 "): %s\n",
+		bad_bits, path);
+	/* return success to keep looping */
+	return 1;
+}
+
+/**
+ * Iterate over all audio files and check the attribute bit mask.
+ *
+ * \param att_mask The mask of all valid attributes.
+ * \param pb Used for reporting inconsistencies.
+ *
+ * This reads the attribute bit mask of each audio file from the afs info
+ * structure stored in the audio file table and verifies that all set bits are
+ * also turned on in \a att_mask, i.e., correspond to an attribute of the
+ * attribute table. Audio files for which this is not the case are reported via
+ * \a pb.
+ *
+ * \return Standard. Inconsistencies are not regarded as errors.
+ *
+ * \sa \ref attribute_check_callback().
+ */
+int aft_check_attributes(uint64_t att_mask, struct para_buffer *pb)
+{
+	struct aft_check_atts_data acad = {.att_mask = att_mask, .pb = pb};
+
+	para_printf(pb, "checking attributes, mask: %" PRIx64 "\n", att_mask);
+	return audio_file_loop(&acad, check_atts_of_audio_file);
 }
 
 /**
@@ -2761,11 +2663,9 @@ static int aft_event_handler(enum afs_events event, struct para_buffer *pb,
 	switch (event) {
 	case ATTRIBUTE_REMOVE: {
 		const struct rmatt_event_data *red = data;
-		ret = para_printf(pb, "clearing attribute %s (bit %u) from all "
+		para_printf(pb, "clearing attribute %s (bit %u) from all "
 			"entries in the audio file table\n", red->name,
 			red->bitnum);
-		if (ret < 0)
-			return ret;
 		return audio_file_loop(data, clear_attribute);
 	} case AFSI_CHANGE: {
 		struct afsi_change_event_data *aced = data;