path: root/aft.c

/* SPDX-License-Identifier: GPL-2.0 */

/** \file aft.c Audio file table functions. */

#include <sys/mman.h>
#include <fnmatch.h>
#include <sys/shm.h>
#include <dirent.h>
#include <osl.h>
#include <lopsub.h>

#include "server_cmd.lsg.h"
#include "para.h"
#include "error.h"
#include "crypt.h"
#include "string.h"
#include "afh.h"
#include "afs.h"
#include "fd.h"
#include "ipc.h"
#include "portable_io.h"
#include "sideband.h"
#include "command.h"

/* Data about one audio file. Needed for ls and stat output. */
struct ls_data {
	/* Usual audio format handler information. */
	struct afh_info afhi;
	/* Audio file selector information. */
	struct afs_info afsi;
	/* The full path of the audio file. */
	char *path;
	/* The score value (if -a was given). */
	long score;
	/* The hash value of the audio file data. */
	unsigned char *hash;
};

/*
 * The internal state of the audio file table is described by the following
 * variables which are private to aft.c.
 */
static struct osl_table *audio_file_table; /* NULL if table not open */
static struct osl_row *current_aft_row; /* NULL if no audio file open */
static unsigned char current_hash[HASH_SIZE];

static char *status_items;
static char *parser_friendly_status_items;
/*
 * ->afsi, ->score, and ->hash are initialized when a new audio file is
 * opened. ->afhi and ->path are initialized when the status items are created.
 */
static struct ls_data status_item_ls_data = {.hash = current_hash};

/** The different sorting methods of the ls command. */
enum ls_sorting_method {
	LS_SORT_BY_PATH, /**< -s=p (default) */
	LS_SORT_BY_SCORE, /**< -s=s */
	LS_SORT_BY_LAST_PLAYED, /**< -s=l */
	LS_SORT_BY_NUM_PLAYED, /**< -s=n */
	LS_SORT_BY_FREQUENCY, /**< -s=f */
	LS_SORT_BY_CHANNELS, /**< -s=c */
	LS_SORT_BY_IMAGE_ID, /**< -s=i */
	LS_SORT_BY_LYRICS_ID, /**< -s=y */
	LS_SORT_BY_BITRATE, /**< -s=b */
	LS_SORT_BY_DURATION, /**< -s=d */
	LS_SORT_BY_AUDIO_FORMAT, /**< -s=a */
	LS_SORT_BY_HASH, /**< -s=h */
};

/** The different listing modes of the ls command. */
enum ls_listing_mode {
	LS_MODE_SHORT, /**< Default listing mode. */
	LS_MODE_LONG, /**< -l or -l=l */
	LS_MODE_VERBOSE, /** -l=v */
	LS_MODE_PARSER, /** -l=p */
};

/**
 * The size of the individual output fields of the ls command.
 *
 * These depend on the content being listed. For example, if each listed file
 * is shorter than an hour, the duration format is set to mm:ss. Otherwise it
 * is set to hh:mm:ss.
 */
struct ls_widths {
	/** size of the score field. */
	unsigned short score_width;
	/** size of the image id field. */
	unsigned short image_id_width;
	/** size of the lyrics id field. */
	unsigned short lyrics_id_width;
	/** size of the bitrate field. */
	unsigned short bitrate_width;
	/** size of the frequency field. */
	unsigned short frequency_width;
	/** size of the duration field. */
	unsigned short duration_width;
	/** size of the num played field. */
	unsigned short num_played_width;
	/** size of the amp field. */
	unsigned short amp_width;
	/** size of the audio format field. */
	unsigned short audio_format_width;
};

/* Data passed from the ls command handler to its callback function. */
struct ls_options {
	struct lls_parse_result *lpr;
	/* Derived from lpr */
	enum ls_sorting_method sorting;
	/* Derived from lpr */
	enum ls_listing_mode mode;
	/* Used for long listing mode to align the output fields. */
	struct ls_widths widths;
	/* Size of the \a data array. */
	uint32_t array_size;
	/* Number of used entries in the data array. */
	uint32_t num_matching_paths;
	/* Array of matching entries. */
	struct ls_data *data;
	/* Used to sort the array. */
	struct ls_data **data_ptr;
};

/**
 * Describes the layout of the mmapped-afs info struct.
 *
 * \sa struct \ref afs_info.
 */
enum afsi_offsets {
	/** Where .last_played is stored. */
	AFSI_LAST_PLAYED_OFFSET = 0,
	/** Storage position of the attributes bitmap. */
	AFSI_ATTRIBUTES_OFFSET = 8,
	/** Storage position of the .num_played field. */
	AFSI_NUM_PLAYED_OFFSET = 16,
	/** Storage position of the .image_id field. */
	AFSI_IMAGE_ID_OFFSET = 20,
	/** Storage position of the .lyrics_id field. */
	AFSI_LYRICS_ID_OFFSET = 24,
	/** Storage position of the .audio_format_id field. */
	AFSI_AUDIO_FORMAT_ID_OFFSET = 28,
	/** Storage position of the amplification field. */
	AFSI_AMP_OFFSET = 29,
	/** 2 bytes reserved space for future usage. */
	AFSI_AUDIO_FORMAT_UNUSED_OFFSET = 30,
	/** On-disk storage space needed. */
	AFSI_SIZE = 32
};

/*
 * Convert a struct afs_info to an osl object.
 *
 * \param afsi Pointer to the audio file info to be converted.
 * \param obj Result pointer.
 *
 * \sa \ref load_afsi().
 */
static void save_afsi(struct afs_info *afsi, struct osl_object *obj)
{
	char *buf = obj->data;

	write_u64(buf + AFSI_LAST_PLAYED_OFFSET, afsi->last_played);
	write_u64(buf + AFSI_ATTRIBUTES_OFFSET, afsi->attributes);
	write_u32(buf + AFSI_NUM_PLAYED_OFFSET, afsi->num_played);
	write_u32(buf + AFSI_IMAGE_ID_OFFSET, afsi->image_id);
	write_u32(buf + AFSI_LYRICS_ID_OFFSET, afsi->lyrics_id);
	write_u8(buf + AFSI_AUDIO_FORMAT_ID_OFFSET,
		afsi->audio_format_id);
	write_u8(buf + AFSI_AMP_OFFSET, afsi->amp);
	memset(buf + AFSI_AUDIO_FORMAT_UNUSED_OFFSET, 0, 2);
}

/*
 * Get the audio file selector info struct stored in an osl object.
 *
 * \param afsi Points to the audio_file info structure to be filled in.
 * \param obj The osl object holding the data.
 *
 * \return Standard.
 *
 * \sa \ref save_afsi().
 */
static int load_afsi(struct afs_info *afsi, struct osl_object *obj)
{
	char *buf = obj->data;
	if (obj->size < AFSI_SIZE)
		return -E_BAD_AFSI;
	afsi->last_played = read_u64(buf + AFSI_LAST_PLAYED_OFFSET);
	afsi->attributes = read_u64(buf + AFSI_ATTRIBUTES_OFFSET);
	afsi->num_played = read_u32(buf + AFSI_NUM_PLAYED_OFFSET);
	afsi->image_id = read_u32(buf + AFSI_IMAGE_ID_OFFSET);
	afsi->lyrics_id = read_u32(buf + AFSI_LYRICS_ID_OFFSET);
	afsi->audio_format_id = read_u8(buf +
		AFSI_AUDIO_FORMAT_ID_OFFSET);
	afsi->amp = read_u8(buf + AFSI_AMP_OFFSET);
	return 1;
}

/** The columns of the audio file table. */
enum audio_file_table_columns {
	/** The hash on the content of the audio file. */
	AFTCOL_HASH,
	/** The full path in the filesystem. */
	AFTCOL_PATH,
	/** The audio file selector info. */
	AFTCOL_AFSI,
	/** The audio format handler info. */
	AFTCOL_AFHI,
	/** The chunk table info and the chunk table of the audio file. */
	AFTCOL_CHUNKS,
	/** The number of columns of this table. */
	NUM_AFT_COLUMNS
};

/* 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);
}

static struct osl_column_description aft_cols[] = {
	[AFTCOL_HASH] = {
		.storage_type = OSL_MAPPED_STORAGE,
		.storage_flags = OSL_RBTREE | OSL_FIXED_SIZE | OSL_UNIQUE,
		.name = "hash",
		.compare_function = aft_hash_compare,
		.data_size = HASH_SIZE
	},
	[AFTCOL_PATH] = {
		.storage_type = OSL_MAPPED_STORAGE,
		.storage_flags = OSL_RBTREE | OSL_UNIQUE,
		.name = "path",
		.compare_function = string_compare,
	},
	[AFTCOL_AFSI] = {
		.storage_type = OSL_MAPPED_STORAGE,
		.storage_flags = OSL_FIXED_SIZE,
		.name = "afs_info",
		.data_size = AFSI_SIZE
	},
	[AFTCOL_AFHI] = {
		.storage_type = OSL_MAPPED_STORAGE,
		.name = "afh_info",
	},
	[AFTCOL_CHUNKS] = {
		.storage_type = OSL_DISK_STORAGE,
		.name = "chunks",
	}
};

static struct osl_table_description audio_file_table_desc = {
	.name = "audio-files",
	.num_columns = NUM_AFT_COLUMNS,
	.flags = OSL_LARGE_TABLE,
	.column_descriptions = aft_cols
};

/*
 * Produce a canonicalized absolute pathname.
 *
 * Returns one if the resolved path a directory, zero if it is a regular file,
 * negative on errors.
 */
static int verify_path(const char *orig_path, char **resolved_path)
{
	int ret;
	char *path = NULL;
	struct stat statbuf;

	if (*orig_path != '/') /* we only accept absolute paths */
		goto fail;
	path = realpath(orig_path, NULL);
	if (!path)
		goto fail;
	if (stat(path, &statbuf) < 0)
		goto fail;
	if (S_ISREG(statbuf.st_mode))
		ret = 0;
	else if (S_ISDIR(statbuf.st_mode))
		ret = 1;
	else
		goto fail;
	*resolved_path = path;
	return ret;
fail:
	*resolved_path = NULL;
	free(path);
	return -E_BAD_PATH;
}

/** The on-disk layout of a afhi struct. */
enum afhi_offsets {
	/** Where the number of seconds is stored. */
	AFHI_SECONDS_TOTAL_OFFSET = 0,
	/** Position of the bitrate. */
	AFHI_BITRATE_OFFSET = 4,
	/** Position of the frequency. */
	AFHI_FREQUENCY_OFFSET = 8,
	/** Was: Location of the audio file header. */
	AFHI_UNUSED1_OFFSET = 12,
	/* Length of the audio file header. Zero means: No header. */
	AFHI_HEADER_LEN_OFFSET = 16,
	/** The total number of chunks (4 bytes). */
	CHUNKS_TOTAL_OFFSET = 20,
	/** The length of the audio file header (4 bytes). */
	HEADER_LEN_OFFSET = 24,
	/** Size of the largest chunk in bytes. (4 bytes). */
	AFHI_MAX_CHUNK_SIZE_OFFSET = 28,
	/** The seconds part of the chunk time (4 bytes). */
	CHUNK_TV_TV_SEC_OFFSET = 32,
	/** The microseconds part of the chunk time (4 bytes). */
	CHUNK_TV_TV_USEC_OFFSET = 36,
	/** Number of channels is stored here. (1 byte) */
	AFHI_CHANNELS_OFFSET = 40,
	/** The tag info position. */
	AFHI_INFO_STRING_OFFSET = 41,
	/** Minimal on-disk size of a valid afhi struct. */
	MIN_AFHI_SIZE = 47, /* at least 6 null bytes for techinfo/tags */
};

static unsigned sizeof_afhi_buf(const struct afh_info *afhi)
{
	if (!afhi)
		return 0;
	return MIN_AFHI_SIZE
		+ strlen(afhi->techinfo)
		+ strlen(afhi->tags.artist)
		+ strlen(afhi->tags.title)
		+ strlen(afhi->tags.year)
		+ strlen(afhi->tags.album)
		+ strlen(afhi->tags.comment);
}

static void save_afhi(struct afh_info *afhi, char *buf)
{
	char *p;

	if (!afhi)
		return;
	write_u32(buf + AFHI_SECONDS_TOTAL_OFFSET, afhi->seconds_total);
	write_u32(buf + AFHI_BITRATE_OFFSET, afhi->bitrate);
	write_u32(buf + AFHI_FREQUENCY_OFFSET, afhi->frequency);
	write_u32(buf + AFHI_UNUSED1_OFFSET, 0);
	write_u32(buf + AFHI_HEADER_LEN_OFFSET, afhi->header_len);
	write_u8(buf + AFHI_CHANNELS_OFFSET, afhi->channels);
	write_u32(buf + CHUNKS_TOTAL_OFFSET, afhi->chunks_total);
	write_u32(buf + HEADER_LEN_OFFSET, afhi->header_len);
	write_u32(buf + AFHI_MAX_CHUNK_SIZE_OFFSET, afhi->max_chunk_size);
	write_u32(buf + CHUNK_TV_TV_SEC_OFFSET, afhi->chunk_tv.tv_sec);
	write_u32(buf + CHUNK_TV_TV_USEC_OFFSET, afhi->chunk_tv.tv_usec);
	p = buf + AFHI_INFO_STRING_OFFSET;
	/*
	 * The below sprintf(3) calls are OK because our caller already made
	 * sure that buf is large enough.
	 */
	p += sprintf(p, "%s", afhi->techinfo) + 1;
	p += sprintf(p, "%s", afhi->tags.artist) + 1;
	p += sprintf(p, "%s", afhi->tags.title) + 1;
	p += sprintf(p, "%s", afhi->tags.year) + 1;
	p += sprintf(p, "%s", afhi->tags.album) + 1;
	sprintf(p, "%s", afhi->tags.comment);
}

/* does not load the chunk table */
static void load_afhi(const char *buf, struct afh_info *afhi)
{
	afhi->seconds_total = read_u32(buf + AFHI_SECONDS_TOTAL_OFFSET);
	afhi->bitrate = read_u32(buf + AFHI_BITRATE_OFFSET);
	afhi->frequency = read_u32(buf + AFHI_FREQUENCY_OFFSET);
	afhi->header_len = read_u32(buf + AFHI_HEADER_LEN_OFFSET);
	afhi->channels = read_u8(buf + AFHI_CHANNELS_OFFSET);
	afhi->chunks_total = read_u32(buf + CHUNKS_TOTAL_OFFSET);
	afhi->header_len = read_u32(buf + HEADER_LEN_OFFSET);
	afhi->max_chunk_size = read_u32(buf + AFHI_MAX_CHUNK_SIZE_OFFSET);
	afhi->chunk_tv.tv_sec = read_u32(buf + CHUNK_TV_TV_SEC_OFFSET);
	afhi->chunk_tv.tv_usec = read_u32(buf + CHUNK_TV_TV_USEC_OFFSET);
	afhi->techinfo = (char *)buf + AFHI_INFO_STRING_OFFSET;
	afhi->tags.artist = afhi->techinfo + strlen(afhi->techinfo) + 1;
	afhi->tags.title = afhi->tags.artist + strlen(afhi->tags.artist) + 1;
	afhi->tags.year = afhi->tags.title + strlen(afhi->tags.title) + 1;
	afhi->tags.album = afhi->tags.year + strlen(afhi->tags.year) + 1;
	afhi->tags.comment = afhi->tags.album + strlen(afhi->tags.album) + 1;
}

/* Only used for saving the chunk table, but not for loading. */
static unsigned sizeof_chunk_table(struct afh_info *afhi)
{
	if (!afhi || !afhi->chunk_table)
		return 0;
	return 4 * (afhi->chunks_total + 1);
}

static void save_chunk_table(struct afh_info *afhi, char *buf)
{
	uint32_t n;

	if (!afhi->chunk_table || afhi->chunks_total == 0)
		return;
	for (n = 0; n <= afhi->chunks_total; n++)
		write_u32(buf + 4 * n, afhi->chunk_table[n]);
}

static void load_chunk_table(struct afh_info *afhi, const struct osl_object *ct)
{
	int i;
	size_t sz;

	if (!ct->data || ct->size < 4 * (afhi->chunks_total + 1)) {
		afhi->chunk_table = NULL;
		return;
	}
	sz  = PARA_MIN(((size_t)afhi->chunks_total + 1) * 4, ct->size) + 1;
	afhi->chunk_table = alloc(sz);
	for (i = 0; i <= afhi->chunks_total && i * 4 + 3 < ct->size; i++)
		afhi->chunk_table[i] = read_u32(ct->data + 4 * i);
}

/**
 * Get the row of the audio file table corresponding to the given path.
 *
 * \param path The full path of the audio file.
 * \param row Result pointer.
 *
 * \return Standard.
 */
int aft_get_row_of_path(const char *path, struct osl_row **row)
{
	struct osl_object obj = {.data = (char *)path, .size = strlen(path) + 1};

	return osl(osl_get_row(audio_file_table, AFTCOL_PATH, &obj, row));
}

/* Get the row of the audio file table, given its hash. */
static int aft_get_row_of_hash(unsigned char *hash, struct osl_row **row)
{
	const struct osl_object obj = {.data = hash, .size = HASH_SIZE};
	return osl(osl_get_row(audio_file_table, AFTCOL_HASH, &obj, row));
}

/*
 * Get the audio file selector info object of a row.
 *
 * \param row Pointer to a row in the audio file table.
 * \param obj Result pointer.
 *
 * \return Standard.
 */
static int get_afsi_object_of_row(const struct osl_row *row,
		struct osl_object *obj)
{
	return osl(osl_get_object(audio_file_table, row, AFTCOL_AFSI, obj));
}

/* Get the osl object containing the audio file selector info. */
static int get_afsi_object_of_path(const char *path, struct osl_object *obj)
{
	struct osl_row *row;
	int ret = aft_get_row_of_path(path, &row);
	if (ret < 0)
		return ret;
	return get_afsi_object_of_row(row, obj);
}

/**
 * Get the audio file selector info, given a row of the audio file table.
 *
 * \param row Pointer to a row in the audio file table.
 * \param afsi Result pointer.
 *
 * \return Positive on success, negative on errors.
 */
int get_afsi_of_row(const struct osl_row *row, struct afs_info *afsi)
{
	struct osl_object obj;
	int ret = get_afsi_object_of_row(row, &obj);
	if (ret < 0)
		return ret;
	return load_afsi(afsi, &obj);
}

/* Get the audio file selector info, given the path of an audio table. */
static int get_afsi_of_path(const char *path, struct afs_info *afsi)
{
	struct osl_object obj;
	int ret = get_afsi_object_of_path(path, &obj);
	if (ret < 0)
		return ret;
	return load_afsi(afsi, &obj);
}

/**
 * Get the path of an audio file, given a row of the audio file table.
 *
 * \param row Pointer to a row in the audio file table.
 * \param path Result pointer.
 *
 * The result is a pointer to memory-mapped data. The caller must not attempt
 * to free it.
 *
 * \return Standard.
 */
int get_audio_file_path_of_row(const struct osl_row *row, char **path)
{
	struct osl_object path_obj;
	int ret = osl(osl_get_object(audio_file_table, row, AFTCOL_PATH,
		&path_obj));

	if (ret < 0)
		*path = NULL;
	else
		*path = path_obj.data;
	return ret;
}

/*
 * Get the object that contains the hash value of an audio file.
 *
 * Returns the sanitized return value of the underlying call to
 * osl_get_object().
 */
static int get_hash_object_of_aft_row(const struct osl_row *row,
		struct osl_object *obj)
{
	return osl(osl_get_object(audio_file_table, row, AFTCOL_HASH, obj));
}

/*
 * Get the hash value of an audio file, given a row of the audio file table.
 * The address returned through the hash pointer argument refers to mapped
 * data and must not be freed by the caller.
 */
static int get_hash_of_row(const struct osl_row *row, unsigned char **hash)
{
	struct osl_object obj;
	int ret = get_hash_object_of_aft_row(row, &obj);

	if (ret < 0)
		return ret;
	*hash = obj.data;
	return 1;
}

/**
 * Get the audio format handler info, given a row of the audio file table.
 *
 * \param row Pointer to a row of the audio file table.
 * \param afhi Result pointer.
 *
 * \return The return value of the underlying call to osl_get_object().
 *
 * After the call the members of the afhi structure point to mapped memory
 * which is owned by the osl table, Hence the caller must not attempt to free
 * this memory by calling \ref clear_afhi().
 */
int get_afhi_of_row(const struct osl_row *row, struct afh_info *afhi)
{
	struct osl_object obj;
	int ret;

	assert(row);
	ret = osl(osl_get_object(audio_file_table, row, AFTCOL_AFHI, &obj));
	if (ret < 0)
		return ret;
	load_afhi(obj.data, afhi);
	return 1;
}

/* returns shmid on success */
static int save_afd(struct audio_file_data *afd)
{
	size_t size = sizeof(*afd) + sizeof_chunk_table(&afd->afhi);
	int shmid, ret = shm_new(size);
	void *shm_afd;
	char *buf;

	if (ret < 0)
		return ret;
	shmid = ret;
	ret = shm_attach(shmid, ATTACH_RW, &shm_afd);
	if (ret < 0)
		goto err;
	buf = shm_afd;
	buf += sizeof(*afd);
	save_chunk_table(&afd->afhi, buf);
	*(struct audio_file_data *)shm_afd = *afd;
	shm_detach(shm_afd);
	return shmid;
err:
	shm_destroy(shmid);
	return ret;
}

/**
 * Extract an audio file data structure from a shared memory area.
 *
 * This is called by the virtual streaming system each time a new audio file
 * is about to be streamed.
 *
 * \param shmid Identifies a serialized version of the audio file data.
 * \param afd Result pointer.
 *
 * Attach the shared memory area and populate the fields of the audio file
 * data structure from the contents of the area, allocating the necessary
 * memory on the heap. Then detach the area.
 *
 * \return Standard.
 */
int load_afd(int shmid, struct audio_file_data *afd)
{
	void *shm_afd;
	int ret;
	struct osl_object obj;

	ret = shm_attach(shmid, ATTACH_RO, &shm_afd);
	if (ret < 0)
		return ret;
	ret = shm_size(shmid, &obj.size);
	if (ret < 0)
		goto detach;
	assert(obj.size >= sizeof(*afd));
	*afd = *(struct audio_file_data *)shm_afd;
	obj.data = shm_afd + sizeof(*afd);
	obj.size -= sizeof(*afd);
	load_chunk_table(&afd->afhi, &obj);
	ret = 1;
detach:
	shm_detach(shm_afd);
	return ret;
}

static int get_local_time(uint64_t *seconds, char *buf, size_t size,
		time_t current_time)
{
	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 */

	tm = localtime((time_t *)seconds);
	if (!tm)
		return -E_LOCALTIME;
	if (*seconds > current_time - m && *seconds < current_time + m) {
		if (!strftime(buf, size, "%b %e %k:%M", tm))
			return -E_STRFTIME;
		return 1;
	}
	/*
	 * 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 formatted 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;
}

/** Compute the number of (decimal) digits of a number. */
#define GET_NUM_DIGITS(x, num) { \
	typeof((x)) _tmp = PARA_ABS(x); \
	*num = 1; \
	if ((_tmp)) \
		while ((_tmp) > 9) { \
			(_tmp) /= 10; \
			(*num)++; \
		} \
	}

__a_const static short unsigned get_duration_width(int seconds)
{
	short unsigned width;
	unsigned hours = seconds / 3600, mins = (seconds % 3600) / 60;

	if (!hours) /* less than one hour => m:ss or mm:ss => 4 or 5 digits */
		return 4 + (mins > 9);
	/* more than one hour => h:mm:ss, hh:mm:ss, hhh:mm:ss, ... */
	GET_NUM_DIGITS(hours, &width);
	return width + 6;
}

static void get_duration_buf(int seconds, char *buf, size_t bufsize,
		struct ls_options *opts)
{
	unsigned hours = seconds / 3600, mins = (seconds % 3600) / 60;
	short unsigned max_width;

	if (!hours) { /* m:ss or mm:ss */
		max_width = opts->mode == LS_MODE_LONG?
			opts->widths.duration_width : 4;
		assert(max_width < bufsize - 1);
		sprintf(buf, "%*u:%02d", max_width - 3, mins, seconds % 60);
	} else { /* more than one hour => h:mm:ss, hh:mm:ss, hhh:mm:ss, ... */
		max_width = opts->mode == LS_MODE_LONG?
			opts->widths.duration_width : 7;
		assert(max_width < bufsize - 1);
		sprintf(buf, "%*u:%02u:%02d", max_width - 6, hours, mins,
			seconds % 60);
	}
}

static int write_attribute_items(struct para_buffer *b,
		const char *att_bitmap, struct afs_info *afsi)
{
	char *att_text;
	int ret;

	WRITE_STATUS_ITEM(b, SI_attributes_bitmap, "%s\n", att_bitmap);
	ret = attr_bitmap_to_text(&afsi->attributes, &att_text);
	if (ret < 0)
		return ret;
	WRITE_STATUS_ITEM(b, SI_attributes_txt, "%s\n", att_text);
	free(att_text);
	return ret;
}

static void write_lyrics_items(struct para_buffer *b, struct afs_info *afsi)
{
	char *lyrics_name;

	WRITE_STATUS_ITEM(b, SI_lyrics_id, "%u\n", afsi->lyrics_id);
	lyr_get_name_by_id(afsi->lyrics_id, &lyrics_name);
	WRITE_STATUS_ITEM(b, SI_lyrics_name, "%s\n", lyrics_name?
		lyrics_name : "(none)");
}

static void write_image_items(struct para_buffer *b, struct afs_info *afsi)
{
	char *image_name;

	WRITE_STATUS_ITEM(b, SI_image_id, "%u\n", afsi->image_id);
	img_get_name_by_id(afsi->image_id, &image_name);
	WRITE_STATUS_ITEM(b, SI_image_name, "%s\n", image_name?
		image_name : "(none)");
}

static void write_filename_items(struct para_buffer *b, const char *path,
		bool basename)
{
	const char *slash;

	if (basename) {
		WRITE_STATUS_ITEM(b, SI_basename, "%s\n", path);
		return;
	}
	WRITE_STATUS_ITEM(b, SI_path, "%s\n", path);
	slash = strrchr(path, '/');
	WRITE_STATUS_ITEM(b, SI_basename, "%s\n", slash? slash + 1 : path);
	WRITE_STATUS_ITEM(b, SI_directory, "%.*s\n",
		slash? (int)(slash - path) : (int)strlen(path), path);
}

/*
 * Print the binary representation of the given attribute value as a string of
 * at most 64 characters into the given buffer. If no attributes are defined,
 * max_attr_bitnum will be negative. Return the empty string in this case.
 */
static void get_attribute_bitmap(const uint64_t *atts,
		int max_attr_bitnum, char *buf)
{
	int i;

	for (i = 0; i <= max_attr_bitnum; i++)
		buf[max_attr_bitnum - i] = (*atts & (1ULL << i))? 'x' : '-';
	buf[i] = '\0';
}

static int print_list_item(struct ls_data *d, struct ls_options *opts,
	struct para_buffer *b, time_t current_time, int max_attr_bitnum)
{
	const struct lls_opt_result *r_a = SERVER_CMD_OPT_RESULT(LS, ADMISSIBLE, opts->lpr);
	const struct lls_opt_result *r_b = SERVER_CMD_OPT_RESULT(LS, BASENAME, opts->lpr);
	const struct lls_opt_result *r_d = SERVER_CMD_OPT_RESULT(LS, UNIX_DATE, opts->lpr);
	int ret;
	char att_buf[65];
	char last_played_time[30];
	char duration_buf[30]; /* nobody has an audio file long enough to overflow this */
	struct afs_info *afsi = &d->afsi;
	struct afh_info *afhi = &d->afhi;
	char asc_hash[2 * HASH_SIZE + 1];

	if (opts->mode == LS_MODE_SHORT) {
		para_printf(b, "%s\n", d->path);
		return 1;
	}
	get_attribute_bitmap(&afsi->attributes, max_attr_bitnum, att_buf);
	if (lls_opt_given(r_d))
		sprintf(last_played_time, "%llu",
			(long long unsigned)afsi->last_played);
	else {
		ret = get_local_time(&afsi->last_played, last_played_time,
			sizeof(last_played_time), current_time);
		if (ret < 0)
			return ret;
	}
	get_duration_buf(afhi->seconds_total, duration_buf,
		sizeof(duration_buf), opts);
	if (opts->mode == LS_MODE_LONG) {
		struct ls_widths *w = &opts->widths;
		if (lls_opt_given(r_a))
			para_printf(b, "%*li ", opts->widths.score_width,
				d->score);
		para_printf(b,
			"%s "   /* attributes */
			"%*u "  /* amp */
			"%*u "  /* image_id  */
			"%*u "  /* lyrics_id */
			"%*u "  /* bitrate */
			"%*s "  /* audio format */
			"%*u "  /* frequency */
			"%u "   /* channels */
			"%s "   /* duration */
			"%*u "  /* num_played */
			"%s "   /* last_played */
			"%s\n", /* path */
			att_buf,
			w->amp_width, afsi->amp,
			w->image_id_width, afsi->image_id,
			w->lyrics_id_width, afsi->lyrics_id,
			w->bitrate_width, afhi->bitrate,
			w->audio_format_width,
			audio_format_name(afsi->audio_format_id),
			w->frequency_width, afhi->frequency,
			afhi->channels,
			duration_buf,
			w->num_played_width, afsi->num_played,
			last_played_time,
			d->path
		);
		return 1;
	}
	write_filename_items(b, d->path, lls_opt_given(r_b));
	if (lls_opt_given(r_a))
		WRITE_STATUS_ITEM(b, SI_score, "%li\n", d->score);
	ret = write_attribute_items(b, att_buf, afsi);
	if (ret < 0)
		return ret;
	write_image_items(b, afsi);
	write_lyrics_items(b, afsi);
	hash_to_asc(d->hash, asc_hash);
	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));
	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);
	WRITE_STATUS_ITEM(b, SI_last_played, "%s\n", last_played_time);
	WRITE_STATUS_ITEM(b, SI_num_played, "%u\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);
	WRITE_STATUS_ITEM(b, SI_max_chunk_size, "%" PRIu32 "\n",
		afhi->max_chunk_size);
	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);
	return 1;
}

static void make_inode_status_items(struct para_buffer *pb,
		const char *mtime_str, const struct stat *statbuf)
{
	WRITE_STATUS_ITEM(pb, SI_mtime, "%s\n", mtime_str);
	WRITE_STATUS_ITEM(pb, SI_file_size, "%ld\n", statbuf->st_size / 1024);
}

/**
 * Deallocate and invalidate the status item strings.
 *
 * This needs to be a public function so that afs.c can call it on shutdown.
 */
void free_status_items(void)
{
	freep(&status_items);
	freep(&parser_friendly_status_items);
}

static void make_status_items(void)
{
	const struct lls_command *cmd = SERVER_CMD_CMD_PTR(LS);
	char *argv[] = {"ls", "--admissible", "--listing-mode=verbose"};
	struct ls_options opts = {.mode = LS_MODE_VERBOSE};
	struct para_buffer pb = {.max_size = shm_get_shmmax() - 1};
	time_t current_time;
	int ret;
	struct stat statbuf;
	char mtime_str[30];
	struct tm mtime_tm;
	struct ls_data *d = &status_item_ls_data;
	int max_attr_bitnum;

	free_status_items();
	if (!current_aft_row) /* no audio file open */
		return;
	/*
	 * d->score, d->hash and d->afsi are already initialized, but d->path
	 * and d->afhi are not.
	 */
	ret = get_audio_file_path_of_row(current_aft_row, &d->path);
	if (ret < 0)
		goto out;
	ret = get_afhi_of_row(current_aft_row, &d->afhi);
	if (ret < 0)
		goto out;
	ret = lls_parse(ARRAY_SIZE(argv), argv, cmd, &opts.lpr, NULL);
	assert(ret >= 0);
	time(&current_time);
	max_attr_bitnum = attr_get_max_bitnum();
	ret = print_list_item(d, &opts, &pb, current_time, max_attr_bitnum);
	if (ret < 0)
		goto out;
	if (stat(d->path, &statbuf) < 0) {
		ret = -ERRNO_TO_PARA_ERROR(errno);
		goto out;
	}
	localtime_r(&statbuf.st_mtime, &mtime_tm);
	ret = strftime(mtime_str, 29, "%b %d %Y", &mtime_tm);
	assert(ret > 0); /* number of bytes placed in mtime_str */
	make_inode_status_items(&pb, mtime_str, &statbuf);
	status_items = pb.buf;
	memset(&pb, 0, sizeof(pb));
	pb.max_size = shm_get_shmmax() - 1;
	pb.flags = PBF_SIZE_PREFIX;
	ret = print_list_item(d, &opts, &pb, current_time, max_attr_bitnum);
	if (ret < 0)
		goto out;
	make_inode_status_items(&pb, mtime_str, &statbuf);
	parser_friendly_status_items = pb.buf;
	ret = 1;
out:
	if (ret < 0) {
		PARA_WARNING_LOG("could not create status items: %s\n",
			para_strerror(-ret));
		free_status_items();
	}
	lls_free_parse_result(opts.lpr, cmd);
}

/**
 * Open the audio file with highest score and set up an afd structure.
 *
 * This determines and opens the next audio file, verifies that it did not
 * change by comparing the recomputed the hash value of the file contents
 * against the value stored in the audio file table. If all goes well, it
 * creates a shared memory area containing the serialized version of the afd
 * structure, including the chunk table, if any. The caller can then send the
 * ID of this area and the open fd to the server process.
 *
 * \param fd Result pointer for the file descriptor of the audio file.
 *
 * On success, the numplayed field of the audio file selector info is increased
 * and the lastplayed time is set to the current time. Finally, the score of
 * the audio file is updated.
 *
 * \return Positive shmid on success, negative on errors.
 */
int open_and_update_audio_file(int *fd)
{
	unsigned char file_hash[HASH_SIZE];
	struct osl_object afsi_obj;
	struct afs_info old_afsi;
	int ret;
	struct osl_object map, chunk_table_obj;
	struct ls_data *d = &status_item_ls_data;
	unsigned char *tmp_hash;
	struct audio_file_data afd;
	char *path = NULL;
again:
	ret = current_selector()->get_best(&current_aft_row, &d->score,
		current_selector_instance);
	if (ret < 0)
		return ret;
	ret = get_hash_of_row(current_aft_row, &tmp_hash);
	if (ret < 0)
		goto delete_aft_row_from_score_table;
	/* tmp_hash points to a memory map which may become stale. */
	memcpy(d->hash, tmp_hash, HASH_SIZE);
	ret = get_audio_file_path_of_row(current_aft_row, &path);
	if (ret < 0)
		goto delete_aft_row_from_score_table;
	PARA_NOTICE_LOG("%s\n", path);

	ret = get_afsi_object_of_row(current_aft_row, &afsi_obj);
	if (ret < 0)
		goto delete_aft_row_from_score_table;
	ret = load_afsi(&d->afsi, &afsi_obj);
	if (ret < 0)
		goto delete_aft_row_from_score_table;
	ret = get_afhi_of_row(current_aft_row, &afd.afhi);
	if (ret < 0)
		goto delete_aft_row_from_score_table;
	afd.afhi.chunk_table = NULL;
	ret = osl(osl_open_disk_object(audio_file_table, current_aft_row,
		AFTCOL_CHUNKS, &chunk_table_obj));
	if (ret < 0) {
		if (!afh_supports_dynamic_chunks(d->afsi.audio_format_id))
			goto delete_aft_row_from_score_table;
		PARA_INFO_LOG("no chunk table for %s\n", path);
		chunk_table_obj.data = NULL;
		chunk_table_obj.size = 0;
	} else {
		PARA_INFO_LOG("chunk table: %zu bytes\n", chunk_table_obj.size);
	}
	ret = mmap_full_file(path, O_RDONLY, &map.data, &map.size, fd);
	if (ret < 0)
		goto free_chunk_table;
	hash_function(map.data, map.size, file_hash);
	ret = hash_compare(file_hash, d->hash);
	para_munmap(map.data, map.size);
	if (ret) {
		ret = -E_HASH_MISMATCH;
		goto free_chunk_table;
	}

	old_afsi = d->afsi;
	d->afsi.num_played++;
	d->afsi.last_played = time(NULL);
	save_afsi(&d->afsi, &afsi_obj); /* in-place update */
	d->afsi.last_played = old_afsi.last_played;
	afd.audio_format_id = d->afsi.audio_format_id;
	load_chunk_table(&afd.afhi, &chunk_table_obj);
	make_status_items();

	ret = afs_event(VSS_NEW_AUDIO_FILE, current_aft_row);
	if (ret < 0)
		goto free_chunk_table;
	ret = save_afd(&afd);
free_chunk_table:
	free(afd.afhi.chunk_table);
	if (chunk_table_obj.data)
		osl_close_disk_object(&chunk_table_obj);
delete_aft_row_from_score_table:
	if (ret < 0) {
		if (path)
			PARA_ERROR_LOG("failed to add %s\n", path);
		path = NULL;
		PARA_ERROR_LOG("%s, disabling file\n", para_strerror(-ret));
		ret = current_selector()->invalidate(current_aft_row,
			current_selector_instance);
		if (ret >= 0)
			goto again;
	}
	return ret;
}

static int ls_hash_compare(const void *a, const void *b)
{
	struct ls_data *d1 = *(struct ls_data **)a, *d2 = *(struct ls_data **)b;
	return memcmp(d1->hash, d2->hash, HASH_SIZE);
}

static int ls_audio_format_compare(const void *a, const void *b)
{
	struct ls_data *d1 = *(struct ls_data **)a, *d2 = *(struct ls_data **)b;
	return NUM_COMPARE(d1->afsi.audio_format_id, d2->afsi.audio_format_id);
}

static int ls_duration_compare(const void *a, const void *b)
{
	struct ls_data *d1 = *(struct ls_data **)a, *d2 = *(struct ls_data **)b;
	return NUM_COMPARE(d1->afhi.seconds_total, d2->afhi.seconds_total);
}

static int ls_bitrate_compare(const void *a, const void *b)
{
	struct ls_data *d1 = *(struct ls_data **)a, *d2 = *(struct ls_data **)b;
	return NUM_COMPARE(d1->afhi.bitrate, d2->afhi.bitrate);
}

static int ls_lyrics_id_compare(const void *a, const void *b)
{
	struct ls_data *d1 = *(struct ls_data **)a, *d2 = *(struct ls_data **)b;
	return NUM_COMPARE(d1->afsi.lyrics_id, d2->afsi.lyrics_id);
}

static int ls_image_id_compare(const void *a, const void *b)
{
	struct ls_data *d1 = *(struct ls_data **)a, *d2 = *(struct ls_data **)b;
	return NUM_COMPARE(d1->afsi.image_id, d2->afsi.image_id);
}

static int ls_channels_compare(const void *a, const void *b)
{
	struct ls_data *d1 = *(struct ls_data **)a, *d2 = *(struct ls_data **)b;
	return NUM_COMPARE(d1->afhi.channels, d2->afhi.channels);
}

static int ls_frequency_compare(const void *a, const void *b)
{
	struct ls_data *d1 = *(struct ls_data **)a, *d2 = *(struct ls_data **)b;
	return NUM_COMPARE(d1->afhi.frequency, d2->afhi.frequency);
}

static int ls_num_played_compare(const void *a, const void *b)
{
	struct ls_data *d1 = *(struct ls_data **)a, *d2 = *(struct ls_data **)b;
	return NUM_COMPARE(d1->afsi.num_played, d2->afsi.num_played);
}

static int ls_last_played_compare(const void *a, const void *b)
{
	struct ls_data *d1 = *(struct ls_data **)a, *d2 = *(struct ls_data **)b;
	return NUM_COMPARE(d1->afsi.last_played, d2->afsi.last_played);
}

static int ls_score_compare(const void *a, const void *b)
{
	struct ls_data *d1 = *(struct ls_data **)a, *d2 = *(struct ls_data **)b;
	return NUM_COMPARE(d1->score, d2->score);
}

static int ls_path_compare(const void *a, const void *b)
{
	struct ls_data *d1 = *(struct ls_data **)a, *d2 = *(struct ls_data **)b;
	return strcmp(d1->path, d2->path);
}

static inline bool admissible_only(struct ls_options *opts)
{
	return SERVER_CMD_OPT_GIVEN(LS, ADMISSIBLE, opts->lpr)
		|| opts->sorting == LS_SORT_BY_SCORE;
}

static void sort_matching_paths(struct ls_options *options)
{
	const struct lls_opt_result *r_b = SERVER_CMD_OPT_RESULT(LS, BASENAME,
		options->lpr);
	size_t nmemb = options->num_matching_paths;
	size_t size = sizeof(*options->data_ptr);
	int (*compar)(const void *, const void *);
	int i;

	options->data_ptr = arr_alloc(nmemb, sizeof(*options->data_ptr));
	for (i = 0; i < nmemb; i++)
		options->data_ptr[i] = options->data + i;

	/* In these cases the array is already sorted */
	if (admissible_only(options)) {
		if (options->sorting == LS_SORT_BY_SCORE)
			return;
	} else {
		if (options->sorting == LS_SORT_BY_PATH && !lls_opt_given(r_b))
			return;
	}

	switch (options->sorting) {
	case LS_SORT_BY_PATH:
		compar = ls_path_compare; break;
	case LS_SORT_BY_SCORE:
		compar = ls_score_compare; break;
	case LS_SORT_BY_LAST_PLAYED:
		compar = ls_last_played_compare; break;
	case LS_SORT_BY_NUM_PLAYED:
		compar = ls_num_played_compare; break;
	case LS_SORT_BY_FREQUENCY:
		compar = ls_frequency_compare; break;
	case LS_SORT_BY_CHANNELS:
		compar = ls_channels_compare; break;
	case LS_SORT_BY_IMAGE_ID:
		compar = ls_image_id_compare; break;
	case LS_SORT_BY_LYRICS_ID:
		compar = ls_lyrics_id_compare; break;
	case LS_SORT_BY_BITRATE:
		compar = ls_bitrate_compare; break;
	case LS_SORT_BY_DURATION:
		compar = ls_duration_compare; break;
	case LS_SORT_BY_AUDIO_FORMAT:
		compar = ls_audio_format_compare; break;
	case LS_SORT_BY_HASH:
		compar = ls_hash_compare; break;
	default:
		assert(0); /* command handler already checked the value. */
	}
	qsort(options->data_ptr, nmemb, size, compar);
}

/* TODO: Only compute widths if we need them */
/* Returns: 1: match, 0: no match, <0: error */
static int prepare_ls_row(struct osl_row *aft_row, void *ls_opts)
{
	int ret, i;
	struct ls_options *options = ls_opts;
	bool basename_given = SERVER_CMD_OPT_GIVEN(LS, BASENAME, options->lpr);
	struct ls_data *d;
	struct ls_widths *w;
	unsigned short num_digits;
	unsigned num_inputs;
	char *path;

	ret = get_audio_file_path_of_row(aft_row, &path);
	if (ret < 0)
		return ret;
	if (basename_given) {
		char *p = strrchr(path, '/');
		if (p)
			path = p + 1;
	}
	num_inputs = lls_num_inputs(options->lpr);
	if (num_inputs > 0) {
		for (i = 0; i < num_inputs; i++) {
			ret = fnmatch(lls_input(i, options->lpr), path, 0);
			if (!ret)
				break;
			if (ret == FNM_NOMATCH)
				continue;
			return -E_FNMATCH;
		}
		if (i >= num_inputs) /* no match */
			return 0;
	}
	if (options->num_matching_paths >= options->array_size) {
		options->array_size++;
		options->array_size *= 2;
		options->data = arr_realloc(options->data, options->array_size,
			sizeof(*options->data));
	}
	d = options->data + options->num_matching_paths++;
	ret = get_afsi_of_row(aft_row, &d->afsi);
	if (ret < 0)
		return ret;
	ret = get_afhi_of_row(aft_row, &d->afhi);
	if (ret < 0)
		return ret;
	d->path = path;
	ret = get_hash_of_row(aft_row, &d->hash);
	if (ret < 0)
		goto err;
	w = &options->widths;
	GET_NUM_DIGITS(d->afsi.image_id, &num_digits);
	w->image_id_width = PARA_MAX(w->image_id_width, num_digits);
	GET_NUM_DIGITS(d->afsi.lyrics_id, &num_digits);
	w->lyrics_id_width = PARA_MAX(w->lyrics_id_width, num_digits);
	GET_NUM_DIGITS(d->afhi.bitrate, &num_digits);
	w->bitrate_width = PARA_MAX(w->bitrate_width, num_digits);
	GET_NUM_DIGITS(d->afhi.frequency, &num_digits);
	w->frequency_width = PARA_MAX(w->frequency_width, num_digits);
	GET_NUM_DIGITS(d->afsi.num_played, &num_digits);
	w->num_played_width = PARA_MAX(w->num_played_width, num_digits);
	/* get the number of chars to print this amount of time */
	num_digits = get_duration_width(d->afhi.seconds_total);
	w->duration_width = PARA_MAX(w->duration_width, num_digits);
	GET_NUM_DIGITS(d->afsi.amp, &num_digits);
	w->amp_width = PARA_MAX(w->amp_width, num_digits);
	num_digits = strlen(audio_format_name(d->afsi.audio_format_id));
	w->audio_format_width = PARA_MAX(w->audio_format_width, num_digits);
	return 1;
err:
	return ret;
}

static int prepare_admissible_row(struct osl_row *aft_row, long score, void *data)
{
	struct ls_options *options = data;
	struct ls_widths *w = &options->widths;
	uint32_t idx = options->num_matching_paths;
	unsigned short num_digits;
	int ret;

	ret = prepare_ls_row(aft_row, data);
	if (ret <= 0)
		return ret;
	GET_NUM_DIGITS(score, &num_digits);
	num_digits++; /* add one for the sign (space or "-") */
	w->score_width = PARA_MAX(w->score_width, num_digits);
	options->data[idx].score = score;
	return 1;
}

static int mop_loop(const char *arg, struct afs_callback_arg *aca,
		struct ls_options *opts)
{
	int ret;
	struct selector_instance *si;
	const struct selector_operations *ops;

	if (!arg || strcmp(arg, ".") == 0) {
		si = current_selector_instance;
		if (!si)
			return 0;
		return current_selector()->loop(prepare_admissible_row, si, opts);
	}
	if (!strcmp(arg, "-")) { /* load previous mop */
		ops = selector_ops[previous_selector_id];
		if (!previous_mop) {
			afs_error(aca, "no previous mood/playlist\n");
			return -ERRNO_TO_PARA_ERROR(EINVAL);
		}
		arg = previous_mop;
	} else if (!strncmp(arg, "m/", 2))
		ops = selector_ops[SEL_MOOD];
	else if (!strncmp(arg, "p/", 2))
		ops = selector_ops[SEL_PLAYLIST];
	else {
		afs_error(aca, "bad mood/playlist specifier: %s\n", arg);
		return -ERRNO_TO_PARA_ERROR(EINVAL);
	}
	ret = ops->load(arg + 2, NULL, aca, &si);
	if (ret < 0)
		return ret;
	ret = ops->loop(prepare_admissible_row, si, opts);
	ops->unload(si);
	return ret;
}

static int com_ls_callback(struct afs_callback_arg *aca)
{
	const struct lls_command *cmd = SERVER_CMD_CMD_PTR(LS);
	struct ls_options *opts = aca->query.data;
	int ret;
	time_t current_time;
	const struct lls_opt_result *r_r, *r_a;
	uint32_t limit, k, n;
	int max_attr_bitnum;

	ret = lls_deserialize_parse_result(
		(char *)aca->query.data + sizeof(*opts), cmd, &opts->lpr);
	assert(ret >= 0);
	r_r = SERVER_CMD_OPT_RESULT(LS, REVERSE, opts->lpr);
	r_a = SERVER_CMD_OPT_RESULT(LS, ADMISSIBLE, opts->lpr);
	aca->pbout.flags = (opts->mode == LS_MODE_PARSER)? PBF_SIZE_PREFIX : 0;
	if (admissible_only(opts)) {
		const char *arg = lls_string_val(0, r_a);
		ret = mop_loop(arg, aca, opts);
	} else
		ret = osl(osl_rbtree_loop(audio_file_table, AFTCOL_PATH, opts,
			prepare_ls_row));
	if (ret < 0)
		goto out;
	n = opts->num_matching_paths;
	if (n == 0) {
		ret = lls_num_inputs(opts->lpr) > 0? -E_NO_MATCH : 0;
		goto out;
	}
	sort_matching_paths(opts);
	time(&current_time);
	limit = SERVER_CMD_UINT32_VAL(LS, LIMIT, opts->lpr);
	max_attr_bitnum = attr_get_max_bitnum();
	for (k = 0; k < n && (limit == 0 || k < limit); k++) {
		uint32_t idx = lls_opt_given(r_r)? n - 1 - k : k;
		ret = print_list_item(opts->data_ptr[idx], opts, &aca->pbout,
			current_time, max_attr_bitnum);
		if (ret < 0)
			goto out;
	}
out:
	lls_free_parse_result(opts->lpr, cmd);
	free(opts->data);
	free(opts->data_ptr);
	return ret;
}

static int com_ls(struct command_context *cc, struct lls_parse_result *lpr)
{
	const struct lls_command *cmd = SERVER_CMD_CMD_PTR(LS);
	struct ls_options *opts;
	struct osl_object query;
	const struct lls_opt_result *r_l = SERVER_CMD_OPT_RESULT(LS, LISTING_MODE,
		lpr);
	const struct lls_opt_result *r_s = SERVER_CMD_OPT_RESULT(LS, SORT, lpr);
	int ret;
	char *slpr;

	ret = lls_serialize_parse_result(lpr, cmd, NULL, &query.size);
	assert(ret >= 0);
	query.size += sizeof(*opts);
	query.data = alloc(query.size);
	opts = query.data;
	memset(opts, 0, sizeof(*opts));
	slpr = query.data + sizeof(*opts);
	ret = lls_serialize_parse_result(lpr, cmd, &slpr, NULL);
	assert(ret >= 0);
	opts->mode = LS_MODE_SHORT;
	opts->sorting = LS_SORT_BY_PATH;
	if (lls_opt_given(r_l)) {
		const char *val = lls_string_val(0, r_l);
		if (!strcmp(val, "l") || !strcmp(val, "long"))
			opts->mode = LS_MODE_LONG;
		else if (!strcmp(val, "s") || !strcmp(val, "short"))
			opts->mode = LS_MODE_SHORT;
		else if (!strcmp(val, "v") || !strcmp(val, "verbose"))
			opts->mode = LS_MODE_VERBOSE;
		else if (!strcmp(val, "p") || !strcmp(val, "parser-friendly"))
			opts->mode = LS_MODE_PARSER;
		else {
			ret = -ERRNO_TO_PARA_ERROR(EINVAL);
			goto out;
		}
	}
	if (lls_opt_given(r_s)) {
		const char *val = lls_string_val(0, r_s);
		if (!strcmp(val, "p") || !strcmp(val, "path"))
			opts->sorting = LS_SORT_BY_PATH;
		else if (!strcmp(val, "s") || !strcmp(val, "score"))
			opts->sorting = LS_SORT_BY_SCORE;
		else if (!strcmp(val, "l") || !strcmp(val, "lastplayed"))
			opts->sorting = LS_SORT_BY_LAST_PLAYED;
		else if (!strcmp(val, "n") || !strcmp(val, "numplayed"))
			opts->sorting = LS_SORT_BY_NUM_PLAYED;
		else if (!strcmp(val, "f") || !strcmp(val, "frquency"))
			opts->sorting = LS_SORT_BY_FREQUENCY;
		else if (!strcmp(val, "c") || !strcmp(val, "channels"))
			opts->sorting = LS_SORT_BY_CHANNELS;
		else if (!strcmp(val, "i") || !strcmp(val, "image-id"))
			opts->sorting = LS_SORT_BY_IMAGE_ID;
		else if (!strcmp(val, "y") || !strcmp(val, "lyrics-id"))
			opts->sorting = LS_SORT_BY_LYRICS_ID;
		else if (!strcmp(val, "b") || !strcmp(val, "bitrate"))
			opts->sorting = LS_SORT_BY_BITRATE;
		else if (!strcmp(val, "d") || !strcmp(val, "duration"))
			opts->sorting = LS_SORT_BY_DURATION;
		else if (!strcmp(val, "a") || !strcmp(val, "audio-format"))
			opts->sorting = LS_SORT_BY_AUDIO_FORMAT;
		else if (!strcmp(val, "h") || !strcmp(val, "hash"))
			opts->sorting = LS_SORT_BY_HASH;
		else {
			ret = -ERRNO_TO_PARA_ERROR(EINVAL);
			goto out;
		}
	}
	ret = send_callback_request(com_ls_callback, cc->afs_fd, &query,
		afs_cb_result_handler, cc);
out:
	free(query.data);
	return ret;
}
EXPORT_SERVER_CMD_HANDLER(ls);

/**
 * Call the given function for each file in the audio file table.
 *
 * \param private_data An arbitrary data pointer, passed to \a func.
 * \param func The custom function to be called.
 *
 * \return Standard.
 */
int audio_file_loop(void *private_data, osl_rbtree_loop_func *func)
{
	return osl(osl_rbtree_loop(audio_file_table, AFTCOL_HASH, private_data,
		func));
}

static int find_hash_sister(unsigned char *hash, struct osl_row **result)
{
	int ret = aft_get_row_of_hash(hash, result);

	if (ret == osl(-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(-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 at this offset. */
	CAB_AFHI_OFFSET_POS = 0,
	/** Start of the chunk table (if present). */
	CAB_CHUNKS_OFFSET_POS = 4,
	/** Start of the (serialized) lopsub parse result. */
	CAB_LPR_OFFSET = 8,
	/** Audio format id. */
	CAB_AUDIO_FORMAT_ID_OFFSET = 12,
	/** The hash of the audio file being added. */
	CAB_HASH_OFFSET = 13,
	/** Start of the path of the audio file. */
	CAB_PATH_OFFSET = (CAB_HASH_OFFSET + HASH_SIZE),
};

/*
 * Store the given data to a single buffer. Doesn't need the audio file selector
 * info struct as the server knows it as well.
 *
 * It's OK to call this with afhi == NULL. In this case, the audio format
 * handler info won't be stored in the buffer.
 */
static void save_add_callback_buffer(unsigned char *hash, const char *path,
		struct afh_info *afhi, const char *slpr, size_t slpr_size,
		uint8_t audio_format_num, struct osl_object *obj)
{
	size_t path_len = strlen(path) + 1;
	size_t afhi_size = sizeof_afhi_buf(afhi);
	size_t size = CAB_PATH_OFFSET + path_len + afhi_size
		+ sizeof_chunk_table(afhi) + slpr_size;
	char *buf = alloc(size);
	uint32_t pos;

	assert(size <= ~(uint32_t)0);
	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);
	pos = CAB_PATH_OFFSET + path_len;
	write_u32(buf + CAB_AFHI_OFFSET_POS, pos);
	save_afhi(afhi, buf + pos);
	pos += afhi_size;
	write_u32(buf + CAB_CHUNKS_OFFSET_POS, pos);
	if (afhi) {
		save_chunk_table(afhi, buf + pos);
		pos += sizeof_chunk_table(afhi);
	}
	write_u32(buf + CAB_LPR_OFFSET, pos);
	memcpy(buf + pos, slpr, slpr_size);
	assert(pos + slpr_size == size);
	obj->data = buf;
	obj->size = size;
}

/*

Overview of the add command.

Input: What was passed to the callback by the command handler.
~~~~~~
HS:	Hash sister. Whether an audio file with identical hash
	already exists in the osl database.

PB:	Path brother. Whether a file with the given path exists
	in the table.

F: 	Force flag given. Whether add was called with -f.

output: Action performed by the callback.
~~~~~~~
AFHI: 	Whether afhi and chunk table are computed and sent.
ACTION:	Table modifications to be done by the callback.

+----+----+---+------+---------------------------------------------------+
| HS | PB | F | AFHI | ACTION
+----+----+---+------+---------------------------------------------------+
| Y  |  Y | Y |  Y   | if HS != PB: remove PB. HS: force afhi update,
|                    | update path, keep afsi
+----+----+---+------+---------------------------------------------------+
| Y  |  Y | N |  N   | if HS == PB: do not send callback request at all.
|                    | otherwise: remove PB, HS: update path, keep afhi,
|                    | afsi.
+----+----+---+------+---------------------------------------------------+
| Y  |  N | Y |  Y   | (rename) force afhi update of HS, update path of
|                    | HS, keep afsi
+----+----+---+------+---------------------------------------------------+
| Y  |  N | N |  N   | (file rename) update path of HS, keep afsi, afhi
+----+----+---+------+---------------------------------------------------+
| N  |  Y | Y |  Y   | (file change) update afhi, hash, of PB, keep afsi
|                    | (force has no effect)
+----+----+---+------+---------------------------------------------------+
| N  |  Y | N |  Y   | (file change) update afhi, hash of PB, keep afsi
+----+----+---+------+---------------------------------------------------+
| N  |  N | Y |  Y   | (new file) create new entry (force has no effect)
+----+----+---+------+---------------------------------------------------+
| N  |  N | N |  Y   | (new file) create new entry
+----+----+---+------+---------------------------------------------------+

Notes:

	afhi <=> force or no HS
	F => AFHI

*/

static int com_add_callback(struct afs_callback_arg *aca)
{
	char *buf = aca->query.data, *path;
	struct osl_row *pb, *aft_row;
	struct osl_row *hs;
	struct osl_object objs[NUM_AFT_COLUMNS];
	unsigned char *hash;
	char asc[2 * HASH_SIZE + 1];
	int ret;
	char afsi_buf[AFSI_SIZE];
	uint32_t slpr_offset = read_u32(buf + CAB_LPR_OFFSET);
	char *slpr = buf + slpr_offset;
	struct afs_info default_afsi = {.last_played = 0};
	uint16_t afhi_offset, chunks_offset;
	const struct lls_command *cmd = SERVER_CMD_CMD_PTR(ADD);
	const struct lls_opt_result *r_f, *r_v;

	ret = lls_deserialize_parse_result(slpr, cmd, &aca->lpr);
	assert(ret >= 0);
	r_f = SERVER_CMD_OPT_RESULT(ADD, FORCE, aca->lpr);
	r_v = SERVER_CMD_OPT_RESULT(ADD, VERBOSE, aca->lpr);

	hash = (unsigned char *)buf + CAB_HASH_OFFSET;
	hash_to_asc(hash, asc);
	objs[AFTCOL_HASH].data = buf + CAB_HASH_OFFSET;
	objs[AFTCOL_HASH].size = HASH_SIZE;

	path = buf + CAB_PATH_OFFSET;
	objs[AFTCOL_PATH].data = path;
	objs[AFTCOL_PATH].size = strlen(path) + 1;

	PARA_INFO_LOG("request to add %s\n", path);
	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 && !lls_opt_given(r_f)) {
		if (lls_opt_given(r_v))
			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 (lls_opt_given(r_v))
				para_printf(&aca->pbout, "removing %s\n", path);
			if (current_aft_row == pb)
				current_aft_row = NULL;
			ret = afs_event(AUDIO_FILE_REMOVE, pb);
			if (ret < 0)
				goto out;
			ret = osl(osl_del_row(audio_file_table, pb));
			if (ret < 0)
				goto out;
			pb = NULL;
		}
		/* file rename, update hs' path */
		if (lls_opt_given(r_v)) {
			ret = osl(osl_get_object(audio_file_table, hs,
				AFTCOL_PATH, &obj));
			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;
		if (hs == current_aft_row)
			make_status_items();
		ret = afs_event(AUDIO_FILE_RENAME, hs);
		if (ret < 0)
			goto out;
		if (!lls_opt_given(r_f))
			goto out;
	}
	/* no hs or force mode, child must have sent afhi */
	afhi_offset = read_u32(buf + CAB_AFHI_OFFSET_POS);
	chunks_offset = read_u32(buf + CAB_CHUNKS_OFFSET_POS);
	assert(chunks_offset <= slpr_offset);

	objs[AFTCOL_AFHI].data = buf + afhi_offset;
	objs[AFTCOL_AFHI].size = chunks_offset - afhi_offset;
	ret = -E_NO_AFHI;
	if (!objs[AFTCOL_AFHI].size) /* "impossible" */
		goto out;
	objs[AFTCOL_CHUNKS].data = buf + chunks_offset;
	objs[AFTCOL_CHUNKS].size = slpr_offset - chunks_offset;
	if (pb && !hs) { /* update pb's hash */
		char old_asc[2 * HASH_SIZE + 1];
		unsigned char *old_hash;
		ret = get_hash_of_row(pb, &old_hash);
		if (ret < 0)
			goto out;
		hash_to_asc(old_hash, old_asc);
		if (lls_opt_given(r_v))
			para_printf(&aca->pbout, "file change: %s -> %s\n",
				old_asc, asc);
		ret = osl(osl_update_object(audio_file_table, pb, AFTCOL_HASH,
			&objs[AFTCOL_HASH]));
		if (ret < 0)
			goto out;
	}
	if (hs || pb) { /* (hs != NULL and pb != NULL) implies hs == pb */
		struct osl_row *row = pb? pb : hs;
		/* update afhi and chunk_table */
		if (lls_opt_given(r_v))
			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)
			goto out;
		/* truncate the file to size zero if there is no chunk table */
		ret = osl(osl_update_object(audio_file_table, row, AFTCOL_CHUNKS,
			&objs[AFTCOL_CHUNKS]));
		if (ret < 0)
			goto out;
		if (row == current_aft_row)
			make_status_items();
		ret = afs_event(AFHI_CHANGE, row);
		goto out;
	}
	/* new entry, use default afsi */
	if (lls_opt_given(r_v))
		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_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));
	if (ret < 0)
		goto out;
	ret = afs_event(AUDIO_FILE_ADD, aft_row);
out:
	if (ret < 0)
		afs_error(aca, "could not add %s\n", path);
	lls_free_parse_result(aca->lpr, cmd);
	return ret;
}

/* Used by com_add(). */
struct private_add_data {
	/* The pointer passed to the original command handler. */
	struct command_context *cc;
	/* Contains the flags given at the command line. */
	struct lls_parse_result *lpr;
	/* Serialized lopsub parse result. */
	char *slpr;
	/* Number of bytes. */
	size_t slpr_size;
};

static int path_brother_callback(struct afs_callback_arg *aca)
{
	char *path = aca->query.data;
	struct osl_row *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 int hash_sister_callback(struct afs_callback_arg *aca)
{
	unsigned char *hash = aca->query.data;
	struct osl_row *hash_sister;
	int ret = find_hash_sister(hash, &hash_sister);

	if (ret <= 0)
		return ret;
	return pass_buffer_as_shm(aca->fd, SBD_OUTPUT, (char *)&hash_sister,
		sizeof(hash_sister));
}

static int get_row_pointer_from_result(struct osl_object *result,
		__a_unused uint8_t band, void *private)
{
	struct osl_row **row = private;

	if (band == SBD_OUTPUT)
		*row = *(struct osl_row **)(result->data);
	return 1;
}

static int add_one_audio_file(const char *path, void *private_data)
{
	int ret, send_ret = 1, fd;
	uint8_t format_num = -1;
	struct private_add_data *pad = private_data;
	struct afh_info afhi, *afhi_ptr = NULL;
	struct osl_row *pb = NULL, *hs = NULL; /* path brother/hash sister */
	struct osl_object map, obj = {.data = NULL}, query;
	unsigned char hash[HASH_SIZE];
	bool a_given = SERVER_CMD_OPT_GIVEN(ADD, ALL, pad->lpr);
	bool f_given = SERVER_CMD_OPT_GIVEN(ADD, FORCE, pad->lpr);
	bool l_given = SERVER_CMD_OPT_GIVEN(ADD, LAZY, pad->lpr);
	bool v_given = SERVER_CMD_OPT_GIVEN(ADD, VERBOSE, pad->lpr);

	ret = guess_audio_format(path);
	if (ret < 0 && !a_given) {
		ret = 0;
		if (v_given)
			send_ret = send_sb_va(&pad->cc->scc, SBD_OUTPUT,
				"suffix-ignore: %s\n", path);
		goto out_free;
	}
	query.data = (char *)path;
	query.size = strlen(path) + 1;
	ret = send_callback_request(path_brother_callback, pad->cc->afs_fd,
		&query, get_row_pointer_from_result, &pb);
	if (ret < 0 && ret != osl(-E_OSL_RB_KEY_NOT_FOUND))
		goto out_free;
	ret = 1;
	if (pb && l_given) { /* lazy is really cheap */
		if (v_given)
			send_ret = send_sb_va(&pad->cc->scc, SBD_OUTPUT,
				"lazy-ignore: %s\n", path);
		goto out_free;
	}
	/* We still want to add this file. Compute its hash. */
	ret = mmap_full_file(path, O_RDONLY, &map.data, &map.size, &fd);
	if (ret < 0)
		goto out_free;
	hash_function(map.data, map.size, hash);

	/* Check whether the database contains a file with the same hash. */
	query.data = hash;
	query.size = HASH_SIZE;
	ret = send_callback_request(hash_sister_callback, pad->cc->afs_fd,
		&query, get_row_pointer_from_result, &hs);
	if (ret < 0)
		goto out_unmap;
	/* Return success if we already know this file. */
	ret = 1;
	if (pb && hs && hs == pb && !f_given) {
		if (v_given)
			send_ret = send_sb_va(&pad->cc->scc, SBD_OUTPUT,
				"%s exists, not forcing update\n", path);
		goto out_unmap;
	}
	/*
	 * We won't recalculate the audio format info and the chunk table if
	 * there is a hash sister and FORCE was not given.
	 */
	if (!hs || f_given) {
		ret = compute_afhi(path, map.data, map.size, &afhi);
		if (ret < 0)
			goto out_unmap;
		format_num = ret;
		afhi_ptr = &afhi;
	}
	munmap(map.data, map.size);
	close(fd);
	if (v_given) {
		send_ret = send_sb_va(&pad->cc->scc, SBD_OUTPUT,
			"adding %s\n", path);
		if (send_ret < 0)
			goto out_free;
	}
	save_add_callback_buffer(hash, path, afhi_ptr, pad->slpr,
		pad->slpr_size, format_num, &obj);
	/* Ask afs to consider this entry for adding. */
	ret = send_callback_request(com_add_callback, pad->cc->afs_fd, &obj,
		afs_cb_result_handler, pad->cc);
	goto out_free;

out_unmap:
	close(fd);
	munmap(map.data, map.size);
out_free:
	if (ret < 0 && send_ret >= 0)
		send_ret = send_sb_va(&pad->cc->scc, SBD_ERROR_LOG,
			"failed to add %s (%s)\n", path, para_strerror(-ret));
	free(obj.data);
	clear_afhi(afhi_ptr);
	/* Stop adding files only on send errors. */
	return send_ret;
}

/*
 * Call back once for each regular file below a directory.
 *
 * Traverse the given directory recursively and call the supplied callback for
 * each regular file encountered. The first argument to the callback will be
 * the path to the regular file and the second argument will be the data
 * pointer. All file types except regular files and directories are ignored. In
 * particular, symlinks are not followed. Subdirectories are ignored silently
 * if the calling process has insufficient access permissions.
 */
static int for_each_file_in_dir(const char *dirname,
		int (*func)(const char *, void *), void *data)
{
	int ret;
	DIR *dir;
	struct dirent *entry;

	dir = opendir(dirname);
	if (!dir)
		return errno == EACCES? 1 : -ERRNO_TO_PARA_ERROR(errno);
	/* scan cwd recursively */
	while ((entry = readdir(dir))) {
		char *tmp;
		struct stat s;

		if (!strcmp(entry->d_name, "."))
			continue;
		if (!strcmp(entry->d_name, ".."))
			continue;
		tmp = make_message("%s/%s", dirname, entry->d_name);
		ret = 0;
		if (lstat(tmp, &s) != -1) {
			if (S_ISREG(s.st_mode))
				ret = func(tmp, data);
			else if (S_ISDIR(s.st_mode))
				ret = for_each_file_in_dir(tmp, func, data);
		}
		free(tmp);
		if (ret < 0)
			goto out;
	}
	ret = 1;
out:
	closedir(dir);
	return ret;
}

static int com_add(struct command_context *cc, struct lls_parse_result *lpr)
{
	int i, ret;
	struct private_add_data pad = {.cc = cc, .lpr = lpr};
	const struct lls_command *cmd = SERVER_CMD_CMD_PTR(ADD);
	unsigned num_inputs;
	char *errctx;

	ret = lls(lls_check_arg_count(lpr, 1, INT_MAX, &errctx));
	if (ret < 0) {
		send_errctx(cc, errctx);
		return ret;
	}
	ret = lls_serialize_parse_result(lpr, cmd, &pad.slpr, &pad.slpr_size);
	assert(ret >= 0);
	num_inputs = lls_num_inputs(lpr);
	for (i = 0; i < num_inputs; i++) {
		char *path;
		ret = verify_path(lls_input(i, lpr), &path);
		if (ret < 0) {
			ret = send_sb_va(&cc->scc, SBD_ERROR_LOG, "%s: %s\n",
				lls_input(i, lpr), para_strerror(-ret));
			if (ret < 0)
				goto out;
			continue;
		}
		if (ret == 1) /* directory */
			ret = for_each_file_in_dir(path, add_one_audio_file,
				&pad);
		else /* regular file */
			ret = add_one_audio_file(path, &pad);
		if (ret < 0) {
			send_sb_va(&cc->scc, SBD_OUTPUT, "%s: %s\n", path,
				para_strerror(-ret));
			free(path);
			return ret;
		}
		free(path);
	}
	ret = 1;
out:
	free(pad.slpr);
	return ret;
}
EXPORT_SERVER_CMD_HANDLER(add);

struct change_atts_data {
	uint64_t add_mask, del_mask;
	struct afs_callback_arg *aca;
	bool verbose, dry_run;
};

static int afsi_change(struct osl_row *aft_row)
{
	int ret;

	if (current_aft_row == aft_row) {
		uint64_t old_last_played = status_item_ls_data.afsi.last_played;

		ret = get_afsi_of_row(aft_row, &status_item_ls_data.afsi);
		if (ret < 0)
			return ret;
		status_item_ls_data.afsi.last_played = old_last_played;
		make_status_items();
	}
	return afs_event(AFSI_CHANGE, aft_row); /* notify other tables */
}

static int touch_audio_file(__a_unused struct osl_table *table,
		struct osl_row *row, const char *name, void *data)
{
	struct change_atts_data *cad = data;
	struct afs_callback_arg *aca = cad->aca;
	const struct lls_opt_result *r_n, *r_l, *r_i, *r_y, *r_a, *r_s, *r_u;
	int ret;
	struct osl_object obj;
	struct afs_info old_afsi, new_afsi;
	bool no_options;

	r_n = SERVER_CMD_OPT_RESULT(TOUCH, NUMPLAYED, aca->lpr);
	r_l = SERVER_CMD_OPT_RESULT(TOUCH, LASTPLAYED, aca->lpr);
	r_i = SERVER_CMD_OPT_RESULT(TOUCH, IMAGE_ID, aca->lpr);
	r_y = SERVER_CMD_OPT_RESULT(TOUCH, LYRICS_ID, aca->lpr);
	r_a = SERVER_CMD_OPT_RESULT(TOUCH, AMP, aca->lpr);
	r_s = SERVER_CMD_OPT_RESULT(TOUCH, SET_ATTRIBUTE, aca->lpr);
	r_u = SERVER_CMD_OPT_RESULT(TOUCH, UNSET_ATTRIBUTE, aca->lpr);
	no_options = !lls_opt_given(r_n) && !lls_opt_given(r_l) && !lls_opt_given(r_i)
		&& !lls_opt_given(r_y) && !lls_opt_given(r_a)
		&& !lls_opt_given(r_s) && !lls_opt_given(r_u);

	ret = get_afsi_object_of_row(row, &obj);
	if (ret < 0) {
		afs_error(aca, "cannot touch %s\n", name);
		return ret;
	}
	ret = load_afsi(&old_afsi, &obj);
	if (ret < 0) {
		afs_error(aca, "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 (cad->verbose)
			para_printf(&aca->pbout, "%s: num_played = %u, "
				"last_played = now()\n", name,
				new_afsi.num_played);
	} else {
		if (lls_opt_given(r_l))
			new_afsi.last_played = lls_uint64_val(0, r_l);
		if (lls_opt_given(r_n))
			new_afsi.num_played = lls_uint32_val(0, r_n);
		if (lls_opt_given(r_i))
			new_afsi.image_id = lls_uint32_val(0, r_i);
		if (lls_opt_given(r_y))
			new_afsi.lyrics_id = lls_uint32_val(0, r_y);
		if (lls_opt_given(r_a))
			new_afsi.amp = lls_uint32_val(0, r_a);
		new_afsi.attributes |= cad->add_mask;
		new_afsi.attributes &= ~cad->del_mask;
		if (cad->verbose)
			para_printf(&aca->pbout, "touching %s\n", name);
	}
	if (!cad->dry_run)
		save_afsi(&new_afsi, &obj); /* in-place update */
	return afsi_change(row);
}

/*
 * Embed a change_atts_data structure into a pattern_match_data structure
 * for the for_each_matching_row() iterator, with touch_audio_file() as
 * the iterator callback for matching files.
 */
static int com_touch_callback(struct afs_callback_arg *aca)
{
	const struct lls_command *cmd = SERVER_CMD_CMD_PTR(TOUCH);
	bool p_given;
	const struct lls_opt_result *r_s, *r_u, *r_i, *r_y;
	int ret, s_given, u_given;
	struct change_atts_data cad = {.aca = aca};
	struct pattern_match_data pmd = {
		.table = audio_file_table,
		.loop_col_num = AFTCOL_HASH,
		.match_col_num = AFTCOL_PATH,
		.data = &cad,
		.action = touch_audio_file
	};

	ret = lls_deserialize_parse_result(aca->query.data, cmd, &aca->lpr);
	assert(ret >= 0);
	pmd.lpr = aca->lpr;
	cad.dry_run = SERVER_CMD_OPT_GIVEN(TOUCH, DRY_RUN, aca->lpr);
	cad.verbose = cad.dry_run || SERVER_CMD_OPT_GIVEN(TOUCH,
		VERBOSE, aca->lpr);

	r_s = SERVER_CMD_OPT_RESULT(TOUCH, SET_ATTRIBUTE, aca->lpr);
	s_given = SERVER_CMD_OPT_GIVEN(TOUCH, SET_ATTRIBUTE, aca->lpr);
	for (int i = 0; i < s_given; i++) {
		const char *arg = lls_string_val(i, r_s);
		ret = attr_name_to_bitnum(arg);
		if (ret < 0) {
			afs_error(aca, "cannot get bit number of %s\n", arg);
			goto out;
		}
		cad.add_mask |= 1ULL << ret;
	}
	r_u = SERVER_CMD_OPT_RESULT(TOUCH, UNSET_ATTRIBUTE, aca->lpr);
	u_given = SERVER_CMD_OPT_GIVEN(TOUCH, UNSET_ATTRIBUTE, aca->lpr);
	for (int i = 0; i < u_given; i++) {
		const char *arg = lls_string_val(i, r_u);
		ret = attr_name_to_bitnum(arg);
		if (ret < 0) {
			afs_error(aca, "cannot get bit number of %s\n", arg);
			goto out;
		}
		cad.del_mask |= 1ULL << ret;
	}
	r_i = SERVER_CMD_OPT_RESULT(TOUCH, IMAGE_ID, aca->lpr);
	if (lls_opt_given(r_i)) {
		uint32_t id = lls_uint32_val(0, r_i);
		ret = img_get_name_by_id(id, NULL);
		if (ret < 0) {
			afs_error(aca, "invalid image ID: %u\n", id);
			return ret;
		}
	}
	r_y = SERVER_CMD_OPT_RESULT(TOUCH, LYRICS_ID, aca->lpr);
	if (lls_opt_given(r_y)) {
		uint32_t id = lls_uint32_val(0, r_y);
		ret = lyr_get_name_by_id(id, NULL);
		if (ret < 0) {
			afs_error(aca, "invalid lyrics ID: %u\n", id);
			return ret;
		}
	}
	p_given = SERVER_CMD_OPT_GIVEN(TOUCH, PATHNAME_MATCH, aca->lpr);
	if (p_given)
		pmd.fnmatch_flags |= FNM_PATHNAME;
	ret = for_each_matching_row(&pmd);
	if (ret >= 0 && pmd.num_matches == 0)
		ret = -E_NO_MATCH;
out:
	lls_free_parse_result(aca->lpr, cmd);
	return ret;
}

static int com_touch(struct command_context *cc, struct lls_parse_result *lpr)
{
	const struct lls_command *cmd = SERVER_CMD_CMD_PTR(TOUCH);
	int ret;
	char *errctx;

	ret = lls(lls_check_arg_count(lpr, 1, INT_MAX, &errctx));
	if (ret < 0) {
		send_errctx(cc, errctx);
		return ret;
	}
	return send_lls_callback_request(com_touch_callback, cc->afs_fd, cmd, lpr, cc);
}
EXPORT_SERVER_CMD_HANDLER(touch);

static int remove_audio_file(__a_unused struct osl_table *table,
		struct osl_row *row, const char *name, void *data)
{
	struct afs_callback_arg *aca = data;
	bool v_given = SERVER_CMD_OPT_GIVEN(RM, VERBOSE, aca->lpr);
	int ret;

	if (v_given)
		para_printf(&aca->pbout, "removing %s\n", name);
	if (current_aft_row == row)
		current_aft_row = NULL;
	ret = afs_event(AUDIO_FILE_REMOVE, row);
	if (ret < 0)
		return ret;
	ret = osl(osl_del_row(audio_file_table, row));
	if (ret < 0)
		afs_error(aca, "cannot remove %s\n", name);
	return ret;
}

static int com_rm_callback(struct afs_callback_arg *aca)
{
	const struct lls_command *cmd = SERVER_CMD_CMD_PTR(RM);
	int ret;
	struct pattern_match_data pmd = {
		.table = audio_file_table,
		.loop_col_num = AFTCOL_HASH,
		.match_col_num = AFTCOL_PATH,
		.data = aca,
		.action = remove_audio_file
	};
	bool v_given, p_given, f_given;

	ret = lls_deserialize_parse_result(aca->query.data, cmd, &aca->lpr);
	assert(ret >= 0);
	pmd.lpr = aca->lpr;
	v_given = SERVER_CMD_OPT_GIVEN(RM, VERBOSE, aca->lpr);
	p_given = SERVER_CMD_OPT_GIVEN(RM, PATHNAME_MATCH, aca->lpr);
	f_given = SERVER_CMD_OPT_GIVEN(RM, FORCE, aca->lpr);

	if (p_given)
		pmd.fnmatch_flags |= FNM_PATHNAME;
	ret = for_each_matching_row(&pmd);
	if (ret < 0)
		goto out;
	if (pmd.num_matches == 0) {
		if (!f_given)
			ret = -E_NO_MATCH;
	} else if (v_given)
		para_printf(&aca->pbout, "removed %u file(s)\n",
			pmd.num_matches);
out:
	lls_free_parse_result(aca->lpr, cmd);
	return ret;
}

/* TODO options: -r (recursive) */
static int com_rm(struct command_context *cc, struct lls_parse_result *lpr)
{
	const struct lls_command *cmd = SERVER_CMD_CMD_PTR(RM);
	char *errctx;
	int ret;

	ret = lls(lls_check_arg_count(lpr, 1, INT_MAX, &errctx));
	if (ret < 0) {
		send_errctx(cc, errctx);
		return ret;
	}
	return send_lls_callback_request(com_rm_callback, cc->afs_fd, cmd, lpr, cc);
}
EXPORT_SERVER_CMD_HANDLER(rm);

/* passed to the action handler of the cpsi() command */
struct cpsi_action_data {
	/* Values are copied from here. */
	struct afs_info source_afsi;
	/* What was passed to com_cpsi_callback(). */
	struct afs_callback_arg *aca;
	bool copy_all;
};

static int copy_selector_info(__a_unused struct osl_table *table,
		struct osl_row *row, const char *name, void *data)
{
	struct cpsi_action_data *cad = data;
	struct osl_object target_afsi_obj;
	int ret;
	struct afs_info target_afsi;
	bool a_given, y_given, i_given, l_given, n_given, v_given;

	a_given = SERVER_CMD_OPT_GIVEN(CPSI, ATTRIBUTE_BITMAP, cad->aca->lpr);
	y_given = SERVER_CMD_OPT_GIVEN(CPSI, LYRICS_ID, cad->aca->lpr);
	i_given = SERVER_CMD_OPT_GIVEN(CPSI, IMAGE_ID, cad->aca->lpr);
	l_given = SERVER_CMD_OPT_GIVEN(CPSI, LASTPLAYED, cad->aca->lpr);
	n_given = SERVER_CMD_OPT_GIVEN(CPSI, NUMPLAYED, cad->aca->lpr);
	v_given = SERVER_CMD_OPT_GIVEN(CPSI, VERBOSE, cad->aca->lpr);

	ret = get_afsi_object_of_row(row, &target_afsi_obj);
	if (ret < 0)
		return ret;
	ret = load_afsi(&target_afsi, &target_afsi_obj);
	if (ret < 0)
		return ret;
	if (cad->copy_all || y_given)
		target_afsi.lyrics_id = cad->source_afsi.lyrics_id;
	if (cad->copy_all || i_given)
		target_afsi.image_id = cad->source_afsi.image_id;
	if (cad->copy_all || l_given)
		target_afsi.last_played = cad->source_afsi.last_played;
	if (cad->copy_all || n_given)
		target_afsi.num_played = cad->source_afsi.num_played;
	if (cad->copy_all || a_given)
		target_afsi.attributes = cad->source_afsi.attributes;
	save_afsi(&target_afsi, &target_afsi_obj); /* in-place update */
	if (v_given)
		para_printf(&cad->aca->pbout, "copied afsi to %s\n", name);
	return afsi_change(row);
}

static int com_cpsi_callback(struct afs_callback_arg *aca)
{
	const struct lls_command *cmd = SERVER_CMD_CMD_PTR(CPSI);
	bool a_given, y_given, i_given, l_given, n_given, v_given;
	struct cpsi_action_data cad = {.aca = aca};
	int ret;
	struct pattern_match_data pmd = {
		.table = audio_file_table,
		.loop_col_num = AFTCOL_HASH,
		.match_col_num = AFTCOL_PATH,
		.input_skip = 1, /* skip first argument (source file) */
		.data = &cad,
		.action = copy_selector_info
	};

	ret = lls_deserialize_parse_result(aca->query.data, cmd, &aca->lpr);
	assert(ret >= 0);
	pmd.lpr = aca->lpr;

	a_given = SERVER_CMD_OPT_GIVEN(CPSI, ATTRIBUTE_BITMAP, aca->lpr);
	y_given = SERVER_CMD_OPT_GIVEN(CPSI, LYRICS_ID, aca->lpr);
	i_given = SERVER_CMD_OPT_GIVEN(CPSI, IMAGE_ID, aca->lpr);
	l_given = SERVER_CMD_OPT_GIVEN(CPSI, LASTPLAYED, aca->lpr);
	n_given = SERVER_CMD_OPT_GIVEN(CPSI, NUMPLAYED, aca->lpr);
	v_given = SERVER_CMD_OPT_GIVEN(CPSI, VERBOSE, aca->lpr);
	cad.copy_all = !a_given && !y_given && !i_given && !l_given && !n_given;

	ret = get_afsi_of_path(lls_input(0, aca->lpr), &cad.source_afsi);
	if (ret < 0)
		goto out;
	ret = for_each_matching_row(&pmd);
	if (ret < 0)
		goto out;
	if (pmd.num_matches > 0) {
		if (v_given)
			para_printf(&aca->pbout, "updated afsi of %u file(s)\n",
				pmd.num_matches);
	} else
		ret = -E_NO_MATCH;
out:
	lls_free_parse_result(aca->lpr, cmd);
	return ret;
}

static int com_cpsi(struct command_context *cc, struct lls_parse_result *lpr)
{
	const struct lls_command *cmd = SERVER_CMD_CMD_PTR(CPSI);
	char *errctx;
	int ret = lls(lls_check_arg_count(lpr, 2, INT_MAX, &errctx));
	if (ret < 0) {
		send_errctx(cc, errctx);
		return ret;
	}
	return send_lls_callback_request(com_cpsi_callback, cc->afs_fd, cmd, lpr, cc);
}
EXPORT_SERVER_CMD_HANDLER(cpsi);

static int afs_stat_callback(struct afs_callback_arg *aca)
{
	bool *parser_friendly = aca->query.data;
	char *buf = *parser_friendly?
		parser_friendly_status_items : status_items;

	if (!buf)
		return 0;
	return pass_buffer_as_shm(aca->fd, SBD_OUTPUT, buf, strlen(buf));
}

/**
 * Get the current afs status items from the afs process and send it.
 *
 * \param cc The command context, used e.g. for data encryption.
 * \param parser_friendly Whether parser-friendly output format should be used.
 *
 * As the contents of the afs status items change in time and the command
 * handler only has a COW version created at fork time, it can not send
 * up-to-date afs status items directly. Therefore the usual callback mechanism
 * is used to pass the status items from the afs process to the command handler
 * via a shared memory area and a pipe.
 *
 * \return The return value of the underlying call to \ref send_callback_request().
 */
int send_afs_status(struct command_context *cc, bool parser_friendly)
{
	struct osl_object query = {.data = &parser_friendly,
		.size = sizeof(parser_friendly)};

	return send_callback_request(afs_stat_callback, cc->afs_fd, &query,
		afs_cb_result_handler, cc);
}

struct check_callback_data {
	struct para_buffer *pbout;
	uint64_t defined_attributes;
};

/* returns success on non-fatal errors to keep the loop going */
static int check_audio_file(struct osl_row *row, void *data)
{
	char *path;
	struct stat statbuf;
	struct afs_info afsi;
	char *blob_name;
	struct check_callback_data *ccd = data;
	struct para_buffer *pb = ccd->pbout;
	int ret = get_audio_file_path_of_row(row, &path);

	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) {
		para_printf(pb, "%s: %s\n", path, para_strerror(-ret));
		return 1;
	}
	/*
	 * Check that all bits set in the on-disk afsi correspond to a defined
	 * attribute of the attribute table.
	 */
	if (afsi.attributes & ~ccd->defined_attributes)
		para_printf(pb, "%s: invalid attribute bits\n", path);
	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)
		para_printf(pb, "%s image id %u: %s\n", path, afsi.image_id,
			para_strerror(-ret));
	return 0;
}

/**
 * Check the audio file table for inconsistencies.
 *
 * \param aca Only ->pbout is used for diagnostics.
 *
 * \return Standard. Inconsistencies are reported but not regarded as an error.
 */
int aft_check_callback(struct afs_callback_arg *aca)
{
	struct check_callback_data ccd = {.pbout = &aca->pbout};
	int ret = attr_get_defined_mask(&ccd.defined_attributes);

	if (ret < 0)
		return ret;
	para_printf(&aca->pbout, "checking audio file table...\n");
	return audio_file_loop(&ccd, check_audio_file);
}

/*
 * This leaves current_aft_row unmodified, though stale (pointing to unmapped
 * memory). If the table is being closed because we received SIGHUP,
 * \ref aft_open() below will be called to reload the table, detect that
 * current_aft_row is not NULL, and look up the audio file via the saved
 * hash value to re-create the status items.
 */
static void aft_close(void)
{
	osl_close_table(audio_file_table, OSL_MARK_CLEAN);
	audio_file_table = NULL;
}

static int aft_open(const char *dir)
{
	int ret;
	unsigned num;

	audio_file_table_desc.dir = dir;
	ret = osl(osl_open_table(&audio_file_table_desc, &audio_file_table));
	if (ret < 0)
		return ret;
	assert(osl_get_num_rows(audio_file_table, &num) >= 0);
	PARA_NOTICE_LOG("audio file table contains %u files\n", num);
	if (!current_aft_row) {
		PARA_DEBUG_LOG("no current aft row\n");
		return 1;
	}
	/* SIGHUP case, update current_aft_row */
	ret = aft_get_row_of_hash(current_hash, &current_aft_row);
	if (ret < 0) { /* not fatal */
		PARA_WARNING_LOG("current hash lookup failure: %s\n",
			para_strerror(-ret));
		current_aft_row = NULL;
		return 1;
	}
	PARA_NOTICE_LOG("current audio file hash lookup: success\n");
	return 1;
}

static int aft_create(const char *dir)
{
	audio_file_table_desc.dir = dir;
	return osl(osl_create_table(&audio_file_table_desc));
}

static int aft_event_handler(enum afs_events event, __a_unused void *data)
{
	switch (event) {
	/*
	 * These events are rare. We don't bother to check whether the current
	 * status items are affected and simply recreate them whenever an
	 * audio file is open.
	 */
	case ATTRIBUTE_REMOVE:
	case BLOB_RENAME:
	case BLOB_REMOVE:
	case BLOB_ADD:
		make_status_items();
		return 0;
	default:
		return 0;
	}
}

/** The audio file table contains information about known audio files. */
const struct afs_table_operations aft_ops = {
	.open = aft_open,
	.close = aft_close,
	.create = aft_create,
	.event_handler = aft_event_handler,
};