Implement server side afs callbacks.

[paraslash.git] / afs.c

#include "para.h"
#include "afh.h"
#include "error.h"
#include <dirent.h> /* readdir() */
#include <sys/mman.h>
#include <sys/time.h>
//#include <inttypes.h>

#include "net.h"
#include "afs.h"
#include "ipc.h"
#include "string.h"
#include "list.h"
#include "sched.h"
#include "signal.h"
#include "fd.h"

/** \file afs.c Paraslash's audio file selector. */

/**
 * Compare two osl objects of string type.
 *
 * \param obj1 Pointer to the first object.
 * \param obj2 Pointer to the second object.
 *
 * In any case, only \p MIN(obj1->size, obj2->size) characters of each string
 * are taken into account.
 *
 * \return It returns an integer less than, equal to, or greater than zero if
 * \a obj1 is found, respectively, to be less than, to match, or be greater than
 * obj2.
 *
 * \sa strcmp(3), strncmp(3), osl_compare_func.
 */
int string_compare(const struct osl_object *obj1, const struct osl_object *obj2)
{
        const char *str1 = (const char *)obj1->data;
        const char *str2 = (const char *)obj2->data;
        return strncmp(str1, str2, PARA_MIN(obj1->size, obj2->size));
}

/** The osl tables used by afs. \sa blob.c */
enum afs_table_num {
        /** Contains audio file information. See aft.c. */
        TBLNUM_AUDIO_FILES,
        /** The table for the paraslash attributes. See attribute.c. */
        TBLNUM_ATTRIBUTES,
        /**
         * Paraslash's scoring system is based on Gaussian normal
         * distributions, and the relevant data is stored in the rbtrees of an
         * osl table containing only volatile columns.  See score.c for
         * details.
         */
        TBLNUM_SCORES,
        /**
         * A standard blob table containing the mood definitions. For details
         * see mood.c.
         */
        TBLNUM_MOODS,
        /** A blob table containing lyrics on a per-song basis. */
        TBLNUM_LYRICS,
        /** Another blob table for images (for example album cover art). */
        TBLNUM_IMAGES,
        /** Yet another blob table for storing standard playlists. */
        TBLNUM_PLAYLIST,
        /** How many tables are in use? */
        NUM_AFS_TABLES
};

static struct table_info afs_tables[NUM_AFS_TABLES];

struct command_task {
        /** The file descriptor for the local socket. */
        int fd;
        /**
         * Value sent by the command handlers to identify themselves as
         * children of the running para_server.
         */
        uint32_t cookie;
        /** The associated task structure. */
        struct task task;
};


/**
 * A wrapper for strtol(3).
 *
 * \param str The string to be converted to a long integer.
 * \param result The converted value is stored here.
 *
 * \return Positive on success, -E_ATOL on errors.
 *
 * \sa strtol(3), atoi(3).
 */
int para_atol(const char *str, long *result)
{
        char *endptr;
        long val;
        int ret, base = 10;

        errno = 0; /* To distinguish success/failure after call */
        val = strtol(str, &endptr, base);
        ret = -E_ATOL;
        if (errno == ERANGE && (val == LONG_MAX || val == LONG_MIN))
                goto out; /* overflow */
        if (errno != 0 && val == 0)
                goto out; /* other error */
        if (endptr == str)
                goto out; /* No digits were found */
        if (*endptr != '\0')
                goto out; /* Further characters after number */
        *result = val;
        ret = 1;
out:
        return ret;
}

/**
 * Struct to let para_server call a function specified from child context.
 *
 * Commands that need to change the state of para_server can't
 * change the relevant data structures directly because commands
 * are executed in a child process, i.e. they get their own
 * virtual address space. This structure must be used to let
 * para_server (i.e. the parent process) call a function specified
 * by the child (the command handler).
 *
 * \sa fork(2), ipc.c.
 */
struct callback_data {
        /** The function to be called. */
        callback_function *handler;
        /** The sma for the parameters of the callback function. */
        int query_shmid;
        /** The size of the query sma. */
        size_t query_size;
        /** If the callback produced a result, it is stored in this sma. */
        int result_shmid;
        /** The size of the result sma. */
        size_t result_size;
        /** The return value of the callback function. */
        int callback_ret;
        /** The return value of the callback() procedure. */
        int sma_ret;
};

struct callback_query {
        /** The function to be called. */
        callback_function *handler;
        /** The number of bytes of the query */
        size_t query_size;
};

struct callback_result {
        /** The number of bytes of the result. */
        size_t result_size;
};

static struct callback_data *shm_callback_data;
static int callback_mutex;
static int child_mutex;
static int result_mutex;

/**
 * Ask the parent process to call a given function.
 *
 * \param f The function to be called.
 * \param query Pointer to arbitrary data for the callback.
 * \param result Callback result will be stored here.
 *
 * This function creates a shared memory area, copies the buffer pointed to by
 * \a buf to that area and notifies the parent process that  \a f should be
 * called ASAP. It provides proper locking via semaphores to protect against
 * concurent access to the shared memory area and against concurrent access by
 * another child process that asks to call the same function.
 *
 * \return Negative, if the shared memory area could not be set up. The return
 * value of the callback function otherwise.
 *
 * \sa shm_new(), shm_attach(), shm_detach(), mutex_lock(), mutex_unlock(),
 * shm_destroy(), struct callback_data, send_option_arg_callback_request(),
 * send_standard_callback_request().
 */
int send_callback_request(callback_function *f, struct osl_object *query,
                struct osl_object *result)
{
        struct callback_data cbd = {.handler = f};
        int ret;
        void *query_sma;

        assert(query->data && query->size);
        ret = shm_new(query->size);
        if (ret < 0)
                return ret;
        cbd.query_shmid = ret;
        cbd.query_size = query->size;
        ret = shm_attach(cbd.query_shmid, ATTACH_RW, &query_sma);
        if (ret < 0)
                goto out;
        memcpy(query_sma, query->data, query->size);
        ret = shm_detach(query_sma);
        if (ret < 0)
                goto out;
        /* prevent other children from interacting */
        mutex_lock(child_mutex);
        /* prevent parent from messing with shm_callback_data. */
        mutex_lock(callback_mutex);
        /* all three mutexes are locked, set parameters for callback */
        *shm_callback_data = cbd;
        /* unblock parent */
        mutex_unlock(callback_mutex);
        kill(getppid(), SIGUSR1); /* wake up parent */
        /*
         * At this time only the parent can run. It will execute our callback
         * and unlock the result_mutex when ready to indicate that the child
         * may use the result. So let's sleep on this mutex.
         */
        mutex_lock(result_mutex);
        /* No need to aquire the callback mutex again */
        ret = shm_callback_data->sma_ret;
        if (ret < 0) /* sma problem, callback might not have been executed */
                goto unlock_child_mutex;
        if (shm_callback_data->result_shmid >= 0) { /* parent provided a result */
                void *sma;
                ret = shm_attach(shm_callback_data->result_shmid, ATTACH_RO,
                        &sma);
                if (ret >= 0) {
                        if (result) { /* copy result */
                                result->size = shm_callback_data->result_size;
                                result->data = para_malloc(result->size);
                                memcpy(result->data, sma, result->size);
                                ret = shm_detach(sma);
                                if (ret < 0)
                                        PARA_ERROR_LOG("can not detach result\n");
                        } else
                                PARA_WARNING_LOG("no result pointer\n");
                } else
                        PARA_ERROR_LOG("attach result failed: %d\n", ret);
                if (shm_destroy(shm_callback_data->result_shmid) < 0)
                        PARA_ERROR_LOG("destroy result failed\n");
        } else { /* no result from callback */
                if (result) {
                        PARA_WARNING_LOG("callback has no result\n");
                        result->data = NULL;
                        result->size = 0;
                }
        }
        ret = shm_callback_data->callback_ret;
unlock_child_mutex:
        /* give other children a chance */
        mutex_unlock(child_mutex);
out:
        if (shm_destroy(cbd.query_shmid) < 0)
                PARA_ERROR_LOG("%s\n", "shm destroy error");
        PARA_DEBUG_LOG("callback_ret: %d\n", ret);
        return ret;
}

/**
 * Send a callback request passing an options structure and an argument vector.
 *
 * \param options pointer to an arbitrary data structure.
 * \param argc Argument count.
 * \param argv Standard argument vector.
 * \param f The callback function.
 * \param result The result of the query is stored here.
 *
 * Some commands have a couple of options that are parsed in child context for
 * syntactic correctness and are stored in a special options structure for that
 * command. This function allows to pass such a structure together with a list
 * of further arguments (often a list of audio files) to the parent process.
 *
 * \sa send_standard_callback_request(), send_callback_request().
 */
int send_option_arg_callback_request(struct osl_object *options,
                int argc, const char **argv, callback_function *f,
                struct osl_object *result)
{
        char *p;
        int i, ret;
        struct osl_object query = {.size = options? options->size : 0};

        for (i = 0; i < argc; i++)
                query.size += strlen(argv[i]) + 1;
        query.data = para_malloc(query.size);
        p = query.data;
        if (options) {
                memcpy(query.data, options->data, options->size);
                p += options->size;
        }
        for (i = 0; i < argc; i++) {
                strcpy(p, argv[i]); /* OK */
                p += strlen(argv[i]) + 1;
        }
        ret = send_callback_request(f, &query, result);
        free(query.data);
        return ret;
}

/**
 * Send a callback request with an argument vector only.
 *
 * \param argc The same meaning as in send_option_arg_callback_request().
 * \param argv The same meaning as in send_option_arg_callback_request().
 * \param f The same meaning as in send_option_arg_callback_request().
 * \param result The same meaning as in send_option_arg_callback_request().
 *
 * This is similar to send_option_arg_callback_request(), but no options buffer
 * is passed to the parent process.
 *
 * \return The return value of the underlying call to
 * send_option_arg_callback_request().
 */
int send_standard_callback_request(int argc, const char **argv,
                callback_function *f, struct osl_object *result)
{
        return send_option_arg_callback_request(NULL, argc, argv, f, result);
}

/*
 * write input from fd to dynamically allocated char array,
 * but maximal max_size byte. Return size.
 */
static int fd2buf(int fd, char **buf, int max_size)
{
        const size_t chunk_size = 1024;
        size_t size = 2048;
        char *p;
        int ret;

        *buf = para_malloc(size * sizeof(char));
        p = *buf;
        while ((ret = read(fd, p, chunk_size)) > 0) {
                p += ret;
                if ((p - *buf) + chunk_size >= size) {
                        char *tmp;

                        size *= 2;
                        if (size > max_size) {
                                ret = -E_INPUT_TOO_LARGE;
                                goto out;
                        }
                        tmp = para_realloc(*buf, size);
                        p = (p - *buf) + tmp;
                        *buf = tmp;
                }
        }
        if (ret < 0) {
                ret = -E_READ;
                goto out;
        }
        ret = p - *buf;
out:
        if (ret < 0 && *buf)
                free(*buf);
        return ret;
}

/**
 * Read from stdin, and send the result to the parent process.
 *
 * \param arg_obj Pointer to the arguments to \a f.
 * \param f The callback function.
 * \param max_len Don't read more than that many bytes from stdin.
 * \param result The result of the query is stored here.
 *
 * This function is used by commands that wish to let para_server store
 * arbitrary data specified by the user (for instance the add_blob family of
 * commands). First, at most \a max_len bytes are read from stdin, the result
 * is concatenated with the buffer given by \a arg_obj, and the combined buffer
 * is made available to the parent process via shared memory.
 *
 * \return Negative on errors, the return value of the underlying call to
 * send_callback_request() otherwise.
 */
int stdin_command(struct osl_object *arg_obj, callback_function *f,
                unsigned max_len, struct osl_object *result)
{
        char *stdin_buf;
        size_t stdin_len;
        struct osl_object query;
        int ret = fd2buf(STDIN_FILENO, &stdin_buf, max_len);

        if (ret < 0)
                return ret;
        stdin_len = ret;
        query.size = arg_obj->size + stdin_len;
        query.data = para_malloc(query.size);
        memcpy(query.data, arg_obj->data, arg_obj->size);
        memcpy((char *)query.data + arg_obj->size, stdin_buf, stdin_len);
        free(stdin_buf);
        ret = send_callback_request(f, &query, result);
        free(query.data);
        return ret;
}

/**
 * Open the audio file with highest score.
 *
 * \param afd Audio file data is returned here.
 *
 * This stores all information for streaming the "best" audio file
 * in the \a afd structure.
 *
 * \return Positive on success, negative on errors.
 *
 * \sa close_audio_file(), open_and_update_audio_file().
 */
int open_next_audio_file(struct audio_file_data *afd)
{
        struct osl_row *aft_row;
        int ret;
        for (;;) {
                ret = score_get_best(&aft_row, &afd->score);
                if (ret < 0)
                        return ret;
                ret = open_and_update_audio_file(aft_row, afd);
                if (ret >= 0)
                        return ret;
        }
}

/**
 * Free all resources which were allocated by open_next_audio_file().
 *
 * \param afd The structure previously filled in by open_next_audio_file().
 *
 * \return The return value of the underlying call to para_munmap().
 *
 * \sa open_next_audio_file().
 */
int close_audio_file(struct audio_file_data *afd)
{
        free(afd->afhi.chunk_table);
        return para_munmap(afd->map.data, afd->map.size);
}

#if 0
static void play_loop(enum play_mode current_play_mode)
{
        int i, ret;
        struct audio_file_data afd;

        afd.current_play_mode = current_play_mode;
        for (i = 0; i < 0; i++) {
                ret = open_next_audio_file(&afd);
                if (ret < 0) {
                        PARA_ERROR_LOG("failed to open next audio file: %d\n", ret);
                        return;
                }
                PARA_NOTICE_LOG("next audio file: %s, score: %li\n", afd.path, afd.score);
                sleep(1);
                close_audio_file(&afd);
        }
}
#endif


static enum play_mode init_admissible_files(void)
{
        int ret;
        char *given_mood, *given_playlist;

        given_mood = "mood_that_was_given_at_the_command_line";
        given_playlist = "given_playlist";

        if (given_mood) {
                ret = mood_open(given_mood);
                if (ret >= 0) {
                        if (given_playlist)
                                PARA_WARNING_LOG("ignoring playlist %s\n",
                                        given_playlist);
                        return PLAY_MODE_MOOD;
                }
        }
        if (given_playlist) {
                ret = playlist_open(given_playlist);
                if (ret >= 0)
                        return PLAY_MODE_PLAYLIST;
        }
        ret = mood_open(NULL); /* open first available mood */
        if (ret >= 0)
                return PLAY_MODE_MOOD;
        mood_open(""); /* open dummy mood, always successful */
        return PLAY_MODE_MOOD;
}

static int setup_command_socket_or_die(void)
{
        int ret;
        char *socket_name = "/tmp/afs_command_socket";
        struct sockaddr_un unix_addr;

        unlink(socket_name);
        ret = create_local_socket(socket_name, &unix_addr,
                S_IRUSR | S_IWUSR | S_IRGRP | S_IWGRP | S_IWOTH);
        if (ret < 0)
                exit(EXIT_FAILURE);
        if (listen(ret , 5) < 0) {
                PARA_EMERG_LOG("%s", "can not listen on socket\n");
                exit(EXIT_FAILURE);
        }
        PARA_INFO_LOG("listening on command socket %s (fd %d)\n", socket_name,
                ret);
        return ret;
}

static int server_socket;

void loop(void)
{
        for (;;)
                sleep(1);
}

static void afs_shutdown(enum osl_close_flags flags)
{
        PARA_NOTICE_LOG("cleaning up\n");
        score_shutdown(flags);
        attribute_shutdown(flags);
        mood_close();
        playlist_close();
        moods_shutdown(flags);
        playlists_shutdown(flags);
        lyrics_shutdown(flags);
        images_shutdown(flags);
        aft_shutdown(flags);
}

static void signal_pre_select(struct sched *s, struct task *t)
{
        struct signal_task *st = t->private_data;
        t->ret = 1;
        para_fd_set(st->fd, &s->rfds, &s->max_fileno);
}

static void signal_post_select(struct sched *s, struct task *t)
{
        struct signal_task *st = t->private_data;
        t->ret = 1;
        if (!FD_ISSET(st->fd, &s->rfds))
                return;
        st->signum = para_next_signal();
        PARA_NOTICE_LOG("caught signal %d\n", st->signum);
        t->ret = 1;
        if (st->signum == SIGUSR1)
                return; /* ignore SIGUSR1 */
        afs_shutdown(OSL_MARK_CLEAN);
        t->ret = -E_SIGNAL_CAUGHT;
}

static void register_signal_task(void)
{
        static struct signal_task signal_task_struct;
        struct signal_task *st = &signal_task_struct;
        st->fd = para_signal_init();
        PARA_INFO_LOG("signal pipe: fd %d\n", st->fd);
        para_install_sighandler(SIGINT);
        para_install_sighandler(SIGTERM);
        para_install_sighandler(SIGPIPE);

        st->task.pre_select = signal_pre_select;
        st->task.post_select = signal_post_select;
        st->task.private_data = st;
        sprintf(st->task.status, "signal task");
        register_task(&st->task);
}

static void command_pre_select(struct sched *s, struct task *t)
{
        struct command_task *ct = t->private_data;
        t->ret = 1;
        para_fd_set(ct->fd, &s->rfds, &s->max_fileno);
}

/*
 * On errors, negative value is written to fd.
 * On success: If query produced a result, the result_shmid is written to fd.
 * Otherwise, zero is written.
 */
static int call_callback(int fd, int query_shmid)
{
        void *query_shm, *result_shm;
        struct callback_query *cq;
        struct callback_result *cr;
        struct osl_object query, result = {.data = NULL};
        int result_shmid = -1, ret, ret2;

        ret = shm_attach(query_shmid, ATTACH_RO, &query_shm);
        if (ret < 0)
                goto out;
        cq = query_shm;
        query.data = (char *)query_shm + sizeof(*cq);
        query.size = cq->query_size;
        ret = cq->handler(&query, &result);
        ret2 = shm_detach(query_shm);
        if (ret2 < 0 && ret >= 0)
                ret = ret2;
        if (ret < 0)
                goto out;
        ret = 0;
        if (!result.data || !result.size)
                goto out;
        ret = shm_new(result.size + sizeof(struct callback_result));
        if (ret < 0)
                goto out;
        result_shmid = ret;
        ret = shm_attach(result_shmid, ATTACH_RW, &result_shm);
        if (ret < 0)
                goto out;
        cr = result_shm;
        cr->result_size = result.size;
        memcpy(result_shm + sizeof(*cr), result.data, result.size);
        ret = shm_detach(result_shm);
        if (ret < 0)
                goto out;
        ret = result_shmid;
out:
        free(result.data);
        ret2 = send_bin_buffer(fd, (char *)ret, sizeof(int));
        if (ret < 0 || ret2 < 0) {
                if (result_shmid >= 0)
                        if (shm_destroy(result_shmid) < 0)
                                PARA_ERROR_LOG("destroy result failed\n");
                if (ret >= 0)
                        ret = ret2;
        }
        return ret;
}

static void command_post_select(struct sched *s, struct task *t)
{
        struct command_task *ct = t->private_data;
        struct sockaddr_un unix_addr;
        char buf[sizeof(uint32_t) + sizeof(int)];
        uint32_t cookie;
        int query_shmid, fd;

        t->ret = 1;
        if (!FD_ISSET(ct->fd, &s->rfds))
                return;
        t->ret = para_accept(ct->fd, &unix_addr, sizeof(unix_addr));
        if (t->ret < 0)
                return;
        /*
         * The following errors may be caused by a malicious local user. So do
         * not return an error in this case as this would terminate  para_afs
         * and para_server.
         */
        fd = t->ret;
        t->ret = recv_bin_buffer(ct->fd, buf, sizeof(buf));
        if (t->ret < 0) {
                PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-t->ret));
                t->ret = 1;
                goto out;
        }
        if (t->ret != sizeof(buf)) {
                PARA_NOTICE_LOG("short read (%d bytes, expected %d)\n",
                        t->ret, sizeof(buf));
                t->ret = 1;
                goto out;
        }
        cookie = *(uint32_t *)buf;
        if (cookie != ct->cookie) {
                PARA_NOTICE_LOG("received invalid cookie(got %u, expected %u)\n",
                        (unsigned)cookie, (unsigned)ct->cookie);
                t->ret = 1;
                goto out;
        }
        query_shmid = *(int *)(buf + sizeof(cookie));
        if (query_shmid < 0) {
                PARA_WARNING_LOG("received invalid query shmid %d)\n",
                        query_shmid);
                t->ret = 1;
                goto out;
        }
        t->ret = call_callback(fd, query_shmid);
        if (t->ret < 0) {
                PARA_NOTICE_LOG("%s\n", PARA_STRERROR(-t->ret));
                t->ret = 1;
                goto out;
        }
out:
        close(fd);
}

static void register_command_task(uint32_t cookie)
{
        static struct command_task command_task_struct;
        struct command_task *ct = &command_task_struct;
        ct->fd = setup_command_socket_or_die();
        ct->cookie = cookie;

        ct->task.pre_select = command_pre_select;
        ct->task.post_select = command_post_select;
        ct->task.private_data = ct;
        sprintf(ct->task.status, "command task");
        register_task(&ct->task);
}

void register_tasks(uint32_t cookie)
{
        register_signal_task();
        register_command_task(cookie);
}

__noreturn int afs_init(uint32_t cookie, int socket_fd)
{
        int ret;
//      void *shm_area;
        enum play_mode current_play_mode;
        struct sched s;

        server_socket = socket_fd;
        PARA_INFO_LOG("server_socket: %d, afs_socket_cookie: %u\n",
                server_socket, (unsigned) cookie);

        ret = attribute_init(&afs_tables[TBLNUM_ATTRIBUTES]);
        if (ret < 0)
                goto attribute_init_error;
        ret = moods_init(&afs_tables[TBLNUM_MOODS]);
        if (ret < 0)
                goto moods_init_error;
        ret = playlists_init(&afs_tables[TBLNUM_PLAYLIST]);
        if (ret < 0)
                goto playlists_init_error;
        ret = lyrics_init(&afs_tables[TBLNUM_LYRICS]);
        if (ret < 0)
                goto lyrics_init_error;
        ret = images_init(&afs_tables[TBLNUM_IMAGES]);
        if (ret < 0)
                goto images_init_error;
        ret = score_init(&afs_tables[TBLNUM_SCORES]);
        if (ret < 0)
                goto score_init_error;
        ret = aft_init(&afs_tables[TBLNUM_AUDIO_FILES]);
        if (ret < 0)
                goto aft_init_error;

        current_play_mode = init_admissible_files();
        register_tasks(cookie);
        s.default_timeout.tv_sec = 0;
        s.default_timeout.tv_usec = 99 * 1000;
        sched(&s);

#if 0
        ret = shm_new(sizeof(struct callback_data));
        if (ret < 0)
                return ret;
        shmid = ret;
        ret = shm_attach(shmid, ATTACH_RW, &shm_area);
        if (ret < 0)
                return ret;
        shm_callback_data = shm_area;
        ret = mutex_new();
        if (ret < 0)
                return ret;
        callback_mutex = ret;
        ret = mutex_new();
        if (ret < 0)
                return ret;
        child_mutex = ret;
        ret = mutex_new();
        if (ret < 0)
                return ret;
        result_mutex = ret;
        mutex_lock(result_mutex);
#endif 
aft_init_error:
        score_shutdown(OSL_MARK_CLEAN);
score_init_error:
        images_shutdown(OSL_MARK_CLEAN);
images_init_error:
        lyrics_shutdown(OSL_MARK_CLEAN);
lyrics_init_error:
        playlists_shutdown(OSL_MARK_CLEAN);
playlists_init_error:
        moods_shutdown(OSL_MARK_CLEAN);
moods_init_error:
        attribute_shutdown(OSL_MARK_CLEAN);
attribute_init_error:
        exit(EXIT_FAILURE);
}

static int create_all_tables(void)
{
        int i, ret;

        for (i = 0; i < NUM_AFS_TABLES; i++) {
                struct table_info *ti = afs_tables + i;

                if (ti->flags & TBLFLAG_SKIP_CREATE)
                        continue;
                ret = osl_create_table(ti->desc);
                if (ret < 0)
                        return ret;
        }
        return 1;
}

/* TODO load tables after init */
static int com_init(__a_unused int fd, int argc, const char **argv)
{
        int i, j, ret;
        if (argc == 1)
                return create_all_tables();
        for (i = 1; i < argc; i++) {
                for (j = 0; j < NUM_AFS_TABLES; j++) {
                        struct table_info *ti = afs_tables + j;

                        if (ti->flags & TBLFLAG_SKIP_CREATE)
                                continue;
                        if (strcmp(argv[i], ti->desc->name))
                                continue;
                        PARA_NOTICE_LOG("creating table %s\n", argv[i]);
                        ret = osl_create_table(ti->desc);
                        if (ret < 0)
                                return ret;
                        break;
                }
                if (j == NUM_AFS_TABLES)
                        return -E_BAD_TABLE_NAME;
        }
        return 1;
}

/** Describes a command of para_server. */
struct command {
        /** The name of the command. */
        const char *name;
        /** The handler function. */
        int (*handler)(int fd, int argc, const char **argv);
};

static struct command afs_cmds[] = {
{
        .name = "add",
        .handler = com_add,
},
{
        .name = "addlyr",
        .handler = com_addlyr,
},
{
        .name = "addimg",
        .handler = com_addimg,
},
{
        .name = "addmood",
        .handler = com_addmood,
},
{
        .name = "addpl",
        .handler = com_addpl,
},
{
        .name = "catlyr",
        .handler = com_catlyr,
},
{
        .name = "catimg",
        .handler = com_catimg,
},
{
        .name = "mvimg",
        .handler = com_mvimg,
},
{
        .name = "mvlyr",
        .handler = com_mvlyr,
},
{
        .name = "mvmood",
        .handler = com_mvmood,
},
{
        .name = "mvpl",
        .handler = com_mvpl,
},
{
        .name = "catmood",
        .handler = com_catmood,
},
{
        .name = "catpl",
        .handler = com_catpl,
},
{
        .name = "rmatt",
        .handler = com_rmatt,
},
{
        .name = "init",
        .handler = com_init,
},
{
        .name = "lsatt",
        .handler = com_lsatt,
},
{
        .name = "ls",
        .handler = com_afs_ls,
},
{
        .name = "lslyr",
        .handler = com_lslyr,
},
{
        .name = "lsimg",
        .handler = com_lsimg,
},
{
        .name = "lsmood",
        .handler = com_lsmood,
},
{
        .name = "lspl",
        .handler = com_lspl,
},
{
        .name = "setatt",
        .handler = com_setatt,
},
{
        .name = "addatt",
        .handler = com_addatt,
},
{
        .name = "rm",
        .handler = com_afs_rm,
},
{
        .name = "rmlyr",
        .handler = com_rmlyr,
},
{
        .name = "rmimg",
        .handler = com_rmimg,
},
{
        .name = "rmmood",
        .handler = com_rmmood,
},
{
        .name = "rmpl",
        .handler = com_rmpl,
},
{
        .name = "touch",
        .handler = com_touch,
},
{
        .name = NULL,
}
};

#if 0
static void call_callback(void)
{
        struct osl_object query, result = {.data = NULL};
        int ret, ret2;

        shm_callback_data->result_shmid = -1; /* no result */
        ret = shm_attach(shm_callback_data->query_shmid, ATTACH_RW,
                &query.data);
        if (ret < 0)
                goto out;
        query.size = shm_callback_data->query_size;
        shm_callback_data->callback_ret = shm_callback_data->handler(&query,
                &result);
        if (result.data && result.size) {
                void *sma;
                ret = shm_new(result.size);
                if (ret < 0)
                        goto detach_query;
                shm_callback_data->result_shmid = ret;
                shm_callback_data->result_size = result.size;
                ret = shm_attach(shm_callback_data->result_shmid, ATTACH_RW, &sma);
                if (ret < 0)
                        goto destroy_result;
                memcpy(sma, result.data, result.size);
                ret = shm_detach(sma);
                if (ret < 0) {
                        PARA_ERROR_LOG("detach result failed\n");
                        goto destroy_result;
                }
        }
        ret = 1;
        goto detach_query;
destroy_result:
        if (shm_destroy(shm_callback_data->result_shmid) < 0)
                PARA_ERROR_LOG("destroy result failed\n");
        shm_callback_data->result_shmid = -1;
detach_query:
        free(result.data);
        ret2 = shm_detach(query.data);
        if (ret2 < 0) {
                PARA_ERROR_LOG("detach query failed\n");
                if (ret >= 0)
                        ret = ret2;
        }
out:
        if (ret < 0)
                PARA_ERROR_LOG("sma error %d\n", ret);
        shm_callback_data->sma_ret = ret;
        shm_callback_data->handler = NULL;
        mutex_unlock(result_mutex); /* wake up child */
}

static int got_sigchld;
static void server_loop(int child_pid)
{
//      int status;

        PARA_DEBUG_LOG("server pid: %d, child pid: %d\n",
                getpid(), child_pid);
        for (;;)  {
                mutex_lock(callback_mutex);
                if (shm_callback_data->handler)
                        call_callback();
                mutex_unlock(callback_mutex);
                usleep(100);
                if (!got_sigchld)
                        continue;
                mutex_destroy(result_mutex);
                mutex_destroy(callback_mutex);
                mutex_destroy(child_mutex);
                afs_shutdown(OSL_MARK_CLEAN);
                exit(EXIT_SUCCESS);
        }
}

int main(int argc, const char **argv)
{
        int i, ret = -E_AFS_SYNTAX;

        signal(SIGUSR1, dummy);
        signal(SIGCHLD, sigchld_handler);
        if (argc < 2)
                goto out;
        ret = setup();
//      ret = afs_init();
        if (ret < 0) {
                PARA_EMERG_LOG("afs_init returned %d\n", ret);
                exit(EXIT_FAILURE);
        }
        ret = fork();
        if (ret < 0) {
                ret = -E_FORK;
                goto out;
        }
        if (ret)
                server_loop(ret);
        for (i = 0; cmd[i].name; i++) {
                if (strcmp(cmd[i].name, argv[1]))
                        continue;
                ret = cmd[i].handler(1, argc - 1 , argv + 1);
                goto out;

        }
        PARA_ERROR_LOG("unknown command: %s\n", argv[1]);
        ret = -1;
out:
        if (ret < 0)
                PARA_ERROR_LOG("error %d\n", ret);
        else
                PARA_DEBUG_LOG("%s", "success\n");
        afs_shutdown(0);
        return ret < 0? EXIT_FAILURE : EXIT_SUCCESS;
}
#endif