test-lib: Fix a bash-4.4 issue.
[paraslash.git] / aft.c
diff --git a/aft.c b/aft.c
index 96f65e9..f14440e 100644 (file)
--- 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;