/amanda/tags/amanda261p2/device-src/device.c

/*
 * Copyright (c) 2005-2008 Zmanda Inc.  All Rights Reserved.
 * 
 * This library is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License version 2.1 as 
 * published by the Free Software Foundation.
 * 
 * This library is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public
 * License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public License
 * along with this library; if not, write to the Free Software Foundation,
 * Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA.
 * 
 * Contact information: Zmanda Inc., 465 S Mathlida Ave, Suite 300
 * Sunnyvale, CA 94086, USA, or: http://www.zmanda.com
 */

/* The Device API abstracts device workings, interaction, properties, and
 * capabilities from the rest of the Amanda code base. It supports
 * pluggable modules for different kinds of devices. */

#include "amanda.h"
#include "conffile.h"

#include <regex.h>

#include "device.h"
#include "queueing.h"
#include "device-queueing.h"
#include "property.h"

#include "timestamp.h"
#include "util.h"

/*
 * Prototypes for subclass registration functions
 */

void    null_device_register    (void);
void	rait_device_register	(void);
#ifdef WANT_S3_DEVICE
void    s3_device_register    (void);
#endif
#ifdef WANT_TAPE_DEVICE
void    tape_device_register    (void);
#endif
void    vfs_device_register     (void);

/*
 * Registration infrastructure
 */

static GHashTable* driverList = NULL;

void device_api_init(void) {
    glib_init();
    device_property_init();
    driverList = g_hash_table_new(g_str_hash, g_str_equal);

    /* register other types and devices. */
    null_device_register();
    vfs_device_register();
#ifdef WANT_TAPE_DEVICE
    tape_device_register();
#endif
    rait_device_register();
#ifdef WANT_S3_DEVICE
    s3_device_register();
#endif
}

void
register_device(
    DeviceFactory factory,
    const char ** device_prefix_list)
{
    char ** tmp;

    g_assert(driverList != NULL);
    g_assert(factory != NULL);
    g_return_if_fail(device_prefix_list != NULL);
    g_return_if_fail(*device_prefix_list != NULL);

    tmp = (char**)device_prefix_list;
    while (*tmp != NULL) {
        g_hash_table_insert(driverList, *tmp, (gpointer)factory);
        tmp ++;
    }
}

static DeviceFactory lookup_device_factory(const char *device_type) {
    gpointer key, value;
    g_assert(driverList != NULL);

    if (g_hash_table_lookup_extended(driverList, device_type, &key, &value)) {
        return (DeviceFactory)value;
    } else {
        return NULL;
    }
}

static const GFlagsValue device_status_flags_values[] = {
    { DEVICE_STATUS_SUCCESS,
      "DEVICE_STATUS_SUCCESS",
      "Success" },
    { DEVICE_STATUS_DEVICE_ERROR,
      "DEVICE_STATUS_DEVICE_ERROR",
      "Device error" },
    { DEVICE_STATUS_DEVICE_BUSY,
      "DEVICE_STATUS_DEVICE_BUSY",
      "Device busy" },
    { DEVICE_STATUS_VOLUME_MISSING,
      "DEVICE_STATUS_VOLUME_MISSING",
      "Volume not found" },
    { DEVICE_STATUS_VOLUME_UNLABELED,
      "DEVICE_STATUS_VOLUME_UNLABELED",
      "Volume not labeled" },
    { DEVICE_STATUS_VOLUME_ERROR,
      "DEVICE_STATUS_VOLUME_ERROR",
      "Volume error" },
    { 0, NULL, NULL }
};

GType device_status_flags_get_type(void) {
    static GType type = 0;
    if (G_UNLIKELY(type == 0)) {
        type = g_flags_register_static("DeviceStatusFlags",
                                       device_status_flags_values);
    }
    return type;
}

/* Device class definition starts here. */

struct DevicePrivate_s {
    /* hash table mapping ID to SimpleProperty object */
    GHashTable * simple_properties;

    /* In writing mode, after a short block is written, no additional blocks
     * are allowed the file is finished and a new file started. This is only
     * used for assertions. */
    gboolean wrote_short_block;

    /* Holds an error message if the function returned an error. */
    char * errmsg;

    /* temporary holding place for device_status_error() */
    char * statusmsg;
    DeviceStatusFlags last_status;
};

/* This holds the default response to a particular property. */
typedef struct {
    DeviceProperty *prop;
    GValue response;
    PropertySurety surety;
    PropertySource source;
} SimpleProperty;

#define selfp (self->private)

/* here are local prototypes, so we can make function pointers. */
static void device_init (Device * o);
static void device_class_init (DeviceClass * c);
static void device_base_init (DeviceClass * c);

static void simple_property_free(SimpleProperty *o);

static void default_device_open_device(Device * self, char * device_name,
				    char * device_type, char * device_node);
static gboolean default_device_configure(Device *self, gboolean use_global_config);
static gboolean default_device_write_from_fd(Device *self,
					     queue_fd_t *queue_fd);
static gboolean default_device_read_to_fd(Device *self, queue_fd_t *queue_fd);
static gboolean default_device_property_get_ex(Device * self, DevicePropertyId id,
					       GValue * val,
					       PropertySurety *surety,
					       PropertySource *source);
static gboolean default_device_property_set_ex(Device *self,
					       DevicePropertyId id,
					       GValue * val,
					       PropertySurety surety,
					       PropertySource source);
static void set_properties_from_global_config(Device * device);
static void set_properties_from_device_config(Device * device, device_config_t *dc);

static gboolean property_get_block_size_fn(Device *self,
    DevicePropertyBase *base, GValue *val,
    PropertySurety *surety, PropertySource *source);

static gboolean property_set_block_size_fn(Device *self,
    DevicePropertyBase *base, GValue *val,
    PropertySurety surety, PropertySource source);

static gboolean property_get_min_block_size_fn(Device *self,
    DevicePropertyBase *base, GValue *val,
    PropertySurety *surety, PropertySource *source);

static gboolean property_get_max_block_size_fn(Device *self,
    DevicePropertyBase *base, GValue *val,
    PropertySurety *surety, PropertySource *source);

static gboolean property_get_canonical_name_fn(Device *self,
    DevicePropertyBase *base, GValue *val,
    PropertySurety *surety, PropertySource *source);

/* pointer to the class of our parent */
static GObjectClass *parent_class = NULL;

GType
device_get_type (void)
{
    static GType type = 0;

    if G_UNLIKELY(type == 0) {
        static const GTypeInfo info = {
            sizeof (DeviceClass),
            (GBaseInitFunc) device_base_init,
            (GBaseFinalizeFunc) NULL,
            (GClassInitFunc) device_class_init,
            (GClassFinalizeFunc) NULL,
            NULL /* class_data */,
            sizeof (Device),
            0 /* n_preallocs */,
            (GInstanceInitFunc) device_init,
            NULL
        };
        
        type = g_type_register_static (G_TYPE_OBJECT, "Device", &info,
                                       (GTypeFlags)G_TYPE_FLAG_ABSTRACT);
    }
    
    return type;
}

static void device_finalize(GObject *obj_self) {
    Device *self G_GNUC_UNUSED = DEVICE (obj_self);
    if(G_OBJECT_CLASS(parent_class)->finalize)
        (* G_OBJECT_CLASS(parent_class)->finalize)(obj_self);

    /* Here we call device_finish() if it hasn't been done
       yet. Subclasses may need to do this same check earlier. */
    if (self->access_mode != ACCESS_NULL) {
        device_finish(self);
    }

    amfree(self->device_name);
    amfree(self->volume_label);
    amfree(self->volume_time);
    amfree(self->volume_header);
    amfree(selfp->errmsg);
    amfree(selfp->statusmsg);
    g_hash_table_destroy(selfp->simple_properties);
    amfree(self->private);
}

static void 
device_init (Device * self)
{
    self->private = malloc(sizeof(DevicePrivate));
    self->device_name = NULL;
    self->access_mode = ACCESS_NULL;
    self->is_eof = FALSE;
    self->file = -1;
    self->block = 0;
    self->in_file = FALSE;
    self->volume_label = NULL;
    self->volume_time = NULL;
    self->status = DEVICE_STATUS_SUCCESS;
    self->min_block_size = 1;
    self->max_block_size = SIZE_MAX; /* subclasses *really* should choose something smaller */
    self->block_size = DISK_BLOCK_BYTES;
    selfp->errmsg = NULL;
    selfp->statusmsg = NULL;
    selfp->last_status = 0;
    selfp->simple_properties =
        g_hash_table_new_full(g_direct_hash,
                              g_direct_equal,
                              NULL,
                              (GDestroyNotify) simple_property_free);
}

static void 
device_class_init (DeviceClass * device_class)
{
    GObjectClass *g_object_class = (GObjectClass*) device_class;
    
    parent_class = g_type_class_ref (G_TYPE_OBJECT);
    
    device_class->open_device = default_device_open_device;
    device_class->configure = default_device_configure;
    device_class->write_from_fd = default_device_write_from_fd;
    device_class->read_to_fd = default_device_read_to_fd;
    device_class->property_get_ex = default_device_property_get_ex;
    device_class->property_set_ex = default_device_property_set_ex;
    g_object_class->finalize = device_finalize;
}

static void
device_base_init (DeviceClass * device_class)
{
    /* The base_init function is called once each time a child class is
     * created, before the class_init functions (even our own) are called.  */

    device_class->class_properties = g_array_new(FALSE, TRUE, sizeof(DeviceProperty));
    device_class->class_properties_list = NULL;

    device_class_register_property(device_class, PROPERTY_BLOCK_SIZE,
	    PROPERTY_ACCESS_GET_MASK | PROPERTY_ACCESS_SET_BEFORE_START,
	    property_get_block_size_fn,
	    property_set_block_size_fn);

    device_class_register_property(device_class, PROPERTY_MIN_BLOCK_SIZE,
	    PROPERTY_ACCESS_GET_MASK,
	    property_get_min_block_size_fn,
	    NULL);

    device_class_register_property(device_class, PROPERTY_MAX_BLOCK_SIZE,
	    PROPERTY_ACCESS_GET_MASK,
	    property_get_max_block_size_fn,
	    NULL);

    device_class_register_property(device_class, PROPERTY_CANONICAL_NAME,
	    PROPERTY_ACCESS_GET_MASK,
	    property_get_canonical_name_fn,
	    NULL);

    device_class_register_property(device_class, PROPERTY_CONCURRENCY,
	    PROPERTY_ACCESS_GET_MASK,
	    device_simple_property_get_fn,
	    device_simple_property_set_fn);

    device_class_register_property(device_class, PROPERTY_STREAMING,
	    PROPERTY_ACCESS_GET_MASK,
	    device_simple_property_get_fn,
	    device_simple_property_set_fn);

    device_class_register_property(device_class, PROPERTY_APPENDABLE,
	    PROPERTY_ACCESS_GET_MASK,
	    device_simple_property_get_fn,
	    device_simple_property_set_fn);

    device_class_register_property(device_class, PROPERTY_PARTIAL_DELETION,
	    PROPERTY_ACCESS_GET_MASK,
	    device_simple_property_get_fn,
	    device_simple_property_set_fn);

    device_class_register_property(device_class, PROPERTY_MEDIUM_ACCESS_TYPE,
	    PROPERTY_ACCESS_GET_MASK,
	    device_simple_property_get_fn,
	    device_simple_property_set_fn);
}

static void simple_property_free(SimpleProperty * resp) {
    g_value_unset(&(resp->response));
    amfree(resp);
}

static char *
regex_message(int result, regex_t *regex) {
    char * rval;
    size_t size;

    size = regerror(result, regex, NULL, 0);
    rval = malloc(size);
    regerror(result, regex, rval, size);

    return rval;
}

static gboolean
handle_device_regex(const char * user_name, char ** driver_name,
                    char ** device, char **errmsg) {
    regex_t regex;
    int reg_result;
    regmatch_t pmatch[3];
    static const char * regex_string = "^([a-z0-9]+):(.*)$";

    bzero(&regex, sizeof(regex));

    reg_result = regcomp(&regex, regex_string, REG_EXTENDED | REG_ICASE);
    if (reg_result != 0) {
        char * message = regex_message(reg_result, &regex);
	*errmsg = newvstrallocf(*errmsg, "Error compiling regular expression \"%s\": %s\n",
			      regex_string, message);
	amfree(message);
        return FALSE;
    }

    reg_result = regexec(&regex, user_name, 3, pmatch, 0);
    if (reg_result != 0 && reg_result != REG_NOMATCH) {
        char * message = regex_message(reg_result, &regex);
	*errmsg = newvstrallocf(*errmsg,
			"Error applying regular expression \"%s\" to string \"%s\": %s\n",
			user_name, regex_string, message);
	amfree(message);
        regfree(&regex);
        return FALSE;
    } else if (reg_result == REG_NOMATCH) {
#ifdef WANT_TAPE_DEVICE
	g_warning(
		"\"%s\" uses deprecated device naming convention; \n"
                "using \"tape:%s\" instead.\n",
                user_name, user_name);
        *driver_name = stralloc("tape");
        *device = stralloc(user_name);
#else /* !WANT_TAPE_DEVICE */
	errmsg = newvstrallocf(errmsg, "\"%s\" is not a valid device name.\n", user_name);
	regfree(&regex);
	return FALSE;
#endif /* WANT_TAPE_DEVICE */
    } else {
        *driver_name = find_regex_substring(user_name, pmatch[1]);
        *device = find_regex_substring(user_name, pmatch[2]);
    }
    regfree(&regex);
    return TRUE;
}

/* helper function for device_open */
static Device *
make_null_error(char *errmsg, DeviceStatusFlags status)
{
    DeviceFactory factory;
    Device *device;

    factory = lookup_device_factory("null");
    g_assert(factory != NULL);

    device = factory("null:", "null", "");
    device_set_error(device, errmsg, status);

    return device;
}

Device* 
device_open (char * device_name)
{
    char *device_type = NULL;
    char *device_node = NULL;
    char *errmsg = NULL;
    char *unaliased_name = NULL;
    DeviceFactory factory;
    Device *device;
    device_config_t *dc;

    g_assert(device_name != NULL);

    if (driverList == NULL) {
        g_critical("device_open() called without device_api_init()!");
        g_assert_not_reached();
    }

    if (device_name == NULL)
	return make_null_error(stralloc(_("No device name specified")), DEVICE_STATUS_DEVICE_ERROR);

    /* look up the unaliased device name in the configuration */
    if ((dc = lookup_device_config(device_name))) {
	if (!(unaliased_name = device_config_get_tapedev(dc))
	    || unaliased_name[0] == '\0') {
	    return make_null_error(
		vstrallocf(_("Device '%s' has no tapedev"), device_name),
		DEVICE_STATUS_DEVICE_ERROR);
	}
    } else {
	unaliased_name = device_name;
    }

    if (!handle_device_regex(unaliased_name, &device_type, &device_node,
			     &errmsg)) {
	amfree(device_type);
	amfree(device_node);
	return make_null_error(errmsg, DEVICE_STATUS_DEVICE_ERROR);
    }

    factory = lookup_device_factory(device_type);

    if (factory == NULL) {
	Device *nulldev = make_null_error(vstrallocf(_("Device type %s is not known."),
	    device_type), DEVICE_STATUS_DEVICE_ERROR);
	amfree(device_type);
	amfree(device_node);
	return nulldev;
    }

    device = factory(device_name, device_type, device_node);
    g_assert(device != NULL); /* factories must always return a device */

    amfree(device_type);
    amfree(device_node);

    return device;
}

char *
device_error(Device * self)
{
    if (self == NULL) {
        return device_error_or_status(self);
    } else if (selfp->errmsg) {
	return selfp->errmsg;
    } else {
        return "Unknown Device error";
    }
}

char *
device_status_error(Device * self)
{
    char **status_strv;
    char *statusmsg;

    if (self == NULL) {
        return device_error_or_status(self);
    }

    /* reuse a previous statusmsg, if it was for the same status */
    if (selfp->statusmsg && selfp->last_status == self->status)
	return selfp->statusmsg;

    amfree(selfp->statusmsg);

    status_strv = g_flags_nick_to_strv(self->status, DEVICE_STATUS_FLAGS_TYPE);
    g_assert(g_strv_length(status_strv) > 0);
    if (g_strv_length(status_strv) == 1) {
	statusmsg = stralloc(*status_strv);
    } else {
	char * status_list = g_english_strjoinv(status_strv, "or");
	statusmsg = g_strdup_printf("one of %s", status_list);
	amfree(status_list);
    }
    g_strfreev(status_strv);

    selfp->statusmsg = statusmsg;
    selfp->last_status = self->status;
    return statusmsg;
}

char *
device_error_or_status(Device * self)
{
    if (self == NULL) {
        return "Device is NULL";
    } else if (selfp->errmsg) {
	return selfp->errmsg;
    } else {
	return device_status_error(self);
    }
}

void
device_set_error(Device *self, char *errmsg, DeviceStatusFlags new_flags)
{
    char **flags_strv;
    char *flags_str;
    char *device_name;

    if (!self) {
	g_warning("device_set_error called with a NULL device: '%s'", errmsg? errmsg:"(NULL)");
	amfree(errmsg);
	return;
    }

    device_name = self->device_name? self->device_name : "(unknown device)";

    if (errmsg && (!selfp->errmsg || strcmp(errmsg, selfp->errmsg) != 0))
	g_debug("Device %s error = '%s'", device_name, errmsg);

    amfree(selfp->errmsg);
    selfp->errmsg = errmsg;

    if (new_flags != DEVICE_STATUS_SUCCESS) {
	flags_strv = g_flags_name_to_strv(new_flags, DEVICE_STATUS_FLAGS_TYPE);
	g_assert(g_strv_length(flags_strv) > 0);
	flags_str = g_english_strjoinv(flags_strv, "and");
	g_debug("Device %s setting status flag(s): %s", device_name, flags_str);
	amfree(flags_str);
	g_strfreev(flags_strv);
    }

    self->status = new_flags;
}

char * device_build_amanda_header(Device * self, const dumpfile_t * info,
                                  int * size, gboolean * oneblock) {
    char *amanda_header;
    size_t min_header_length;
    size_t header_buffer_size;

    min_header_length = self->block_size;
    amanda_header = build_header(info, min_header_length);
    header_buffer_size = MAX(min_header_length, strlen(amanda_header)+1);
    if (size != NULL)
        *size = header_buffer_size;
    if (oneblock != NULL)
        *oneblock = (header_buffer_size <= self->block_size);
    return amanda_header;
}

dumpfile_t * make_tapestart_header(Device * self, char * label,
                                   char * timestamp) {
    dumpfile_t * rval;
    GValue val;
    bzero(&val, sizeof(val));

    g_assert(label != NULL);

    rval = malloc(sizeof(*rval));
    fh_init(rval);
    rval->type = F_TAPESTART;
    if (device_property_get(self, PROPERTY_BLOCK_SIZE, &val)) {
	rval->blocksize = g_value_get_int(&val);
	g_value_unset(&val);
    }

    amfree(self->volume_time);
    if (get_timestamp_state(timestamp) == TIME_STATE_REPLACE) {
        self->volume_time = get_proper_stamp_from_time(time(NULL));
    } else {
        self->volume_time = g_strdup(timestamp);
    }
    strncpy(rval->datestamp, self->volume_time, sizeof(rval->datestamp));
    strncpy(rval->name, label, sizeof(rval->name));

    return rval;
}

dumpfile_t * make_tapeend_header(void) {
    dumpfile_t * rval;
    char * timestamp;

    rval = malloc(sizeof(*rval));
    rval->type = F_TAPEEND;
    timestamp = get_timestamp_from_time(time(NULL));
    strncpy(rval->datestamp, timestamp, sizeof(rval->datestamp));
    amfree(timestamp);
    return rval;
}

/* Try setting the blocksize on a device. Check results, fallback, and
 * set error status for problems. */
static gboolean
try_set_blocksize(Device * device, guint blocksize) {
    GValue val;
    gboolean success;
    bzero(&val, sizeof(val));

    g_value_init(&val, G_TYPE_INT);
    g_value_set_int(&val, blocksize);
    success = device_property_set(device, PROPERTY_BLOCK_SIZE, &val);
    g_value_unset(&val);

    if (!success) {
	device_set_error(device,
	    vstrallocf(_("Setting BLOCK_SIZE to %u "
		    "not supported for device %s.\n"),
		    blocksize, device->device_name),
	    DEVICE_STATUS_DEVICE_ERROR);
    }

    return success;
}

/* A GHFunc (callback for g_hash_table_foreach) */
static void set_device_property(gpointer key_p, gpointer value_p,
                                   gpointer user_data_p) {
    char   * property_s = key_p;
    property_t * property = value_p;
    Device * device = user_data_p;
    const DevicePropertyBase* property_base;
    GValue property_value;
    char   * value;

    g_return_if_fail(IS_DEVICE(device));
    g_return_if_fail(property_s != NULL);
    g_return_if_fail(property != NULL);
    g_return_if_fail(property->values != NULL);

    /* don't continue beating on a device that's already erroring */
    if (device_in_error(device)) return;

    property_base = device_property_get_by_name(property_s);
    if (property_base == NULL) {
        /* Nonexistant property name. */
	device_set_error(device,
	    vstrallocf(_("unknown device property name '%s'"), property_s),
	    DEVICE_STATUS_DEVICE_ERROR);
        return;
    }
    if (g_slist_length(property->values) > 1) {
	device_set_error(device,
	    vstrallocf(_("multiple values for device property '%s'"), property_s),
	    DEVICE_STATUS_DEVICE_ERROR);
	return;
    }
    
    bzero(&property_value, sizeof(property_value));
    g_value_init(&property_value, property_base->type);
    value = property->values->data;
    if (!g_value_set_from_string(&property_value, value)) {
        /* Value type could not be interpreted. */
	device_set_error(device,
	    vstrallocf(_("Could not parse property value '%s' for property '%s' (property type %s)"),
                        value, property_base->name, g_type_name(property_base->type)),
	    DEVICE_STATUS_DEVICE_ERROR);
        return;
    } else {
        g_assert (G_VALUE_HOLDS(&property_value, property_base->type));
    }

    if (!device_property_set(device, property_base->ID, &property_value)) {
        /* Device rejects property. */
        if (!device_in_error(device)) {
	    device_set_error(device,
		vstrallocf(_("Could not set property '%s' to '%s' on %s"),
			property_base->name, value, device->device_name),
		DEVICE_STATUS_DEVICE_ERROR);
	}
        return;
    }
}

/* Set up properties based on various taper-related configuration parameters
 * and from the tapetype.
 */
static void
set_properties_from_global_config(Device * device) {
    char * tapetype_name = getconf_str(CNF_TAPETYPE);
    if (tapetype_name != NULL) {
        tapetype_t * tapetype = lookup_tapetype(tapetype_name);
        if (tapetype != NULL) {
            GValue val;
            guint64 length;
            guint blocksize_kb;
            gboolean success;

            bzero(&val, sizeof(GValue));

            if (tapetype_seen(tapetype, TAPETYPE_LENGTH)) {
		length = tapetype_get_length(tapetype);
                g_value_init(&val, G_TYPE_UINT64);
                g_value_set_uint64(&val, length * 1024);
                /* If this fails, it's not really an error. */
                device_property_set(device, PROPERTY_MAX_VOLUME_USAGE, &val);
                g_value_unset(&val);
            }

            if (tapetype_seen(tapetype, TAPETYPE_READBLOCKSIZE)) {
		blocksize_kb = tapetype_get_readblocksize(tapetype);
                g_value_init(&val, G_TYPE_UINT);
                g_value_set_uint(&val, blocksize_kb * 1024);
                success = device_property_set(device,
                                              PROPERTY_READ_BUFFER_SIZE,
                                              &val);
                g_value_unset(&val);
                if (!success) {
		    /* a non-fatal error */
                    g_warning("Setting READ_BUFFER_SIZE to %ju not supported for device %s.",
                            1024*(uintmax_t)blocksize_kb, device->device_name);
                }
            }

            if (tapetype_seen(tapetype, TAPETYPE_BLOCKSIZE)) {
		blocksize_kb = tapetype_get_blocksize(tapetype);
		/* TODO: handle errors */
                (void)try_set_blocksize(device, blocksize_kb * 1024);
            }
        }
    }

    g_hash_table_foreach(getconf_proplist(CNF_DEVICE_PROPERTY),
                         set_device_property, device);
}

/* Set properties specified within a device definition */
static void
set_properties_from_device_config(Device * device, device_config_t *dc) {
    g_hash_table_foreach(device_config_get_property(dc),
                         set_device_property, device);
}

static gboolean
default_device_configure(Device *self, gboolean use_global_config)
{
    device_config_t *dc;

    if (device_in_error(self))
	return FALSE;

    if (use_global_config)
	set_properties_from_global_config(self);

    if (device_in_error(self))
	return FALSE;

    if ((dc = lookup_device_config(self->device_name)))
	set_properties_from_device_config(self, dc);

    return !device_in_error(self);
}

void device_clear_volume_details(Device * device) {
    if (device == NULL || device->access_mode != ACCESS_NULL) {
        return;
    }

    amfree(device->volume_label);
    amfree(device->volume_time);
}

/* Here we put default implementations of virtual functions. Since
   this class is virtual, many of these functions offer at best
   incomplete functionality. But they do offer the useful commonality
   that all devices can expect to need. */

static void default_device_open_device(Device * self, char * device_name,
		    char * device_type G_GNUC_UNUSED, char * device_node G_GNUC_UNUSED) {
    /* Set the device_name property */
    self->device_name = stralloc(device_name);
}

static gboolean
property_get_block_size_fn(
	Device *self,
	DevicePropertyBase *base G_GNUC_UNUSED,
	GValue *val,
	PropertySurety *surety,
	PropertySource *source)
{
    g_value_unset_init(val, G_TYPE_INT);
    g_assert(self->block_size < G_MAXINT); /* gsize -> gint */
    g_value_set_int(val, (gint)self->block_size);

    if (surety)
	*surety = self->block_size_surety;

    if (source)
	*source = self->block_size_source;

    return TRUE;
}

static gboolean
property_set_block_size_fn(
	Device *self,
	DevicePropertyBase *base G_GNUC_UNUSED,
	GValue *val,
	PropertySurety surety,
	PropertySource source)
{
    gint block_size = g_value_get_int(val);

    g_assert(block_size >= 0); /* int -> gsize (unsigned) */
    if ((gsize)block_size < self->min_block_size
       || (gsize)block_size > self->max_block_size)
	return FALSE;

    self->block_size = block_size;
    self->block_size_surety = surety;
    self->block_size_source = source;

    return TRUE;
}

static gboolean
property_get_min_block_size_fn(
	Device *self,
	DevicePropertyBase *base G_GNUC_UNUSED,
	GValue *val,
	PropertySurety *surety,
	PropertySource *source)
{
    g_value_unset_init(val, G_TYPE_UINT);
    g_assert(self->block_size < G_MAXUINT); /* gsize -> guint */
    g_value_set_uint(val, (guint)self->min_block_size);

    if (surety)
	*surety = PROPERTY_SURETY_GOOD;

    if (source)
	*source = PROPERTY_SOURCE_DEFAULT;

    return TRUE;
}

static gboolean
property_get_max_block_size_fn(
	Device *self,
	DevicePropertyBase *base G_GNUC_UNUSED,
	GValue *val,
	PropertySurety *surety,
	PropertySource *source)
{
    g_value_unset_init(val, G_TYPE_UINT);
    g_assert(self->block_size < G_MAXUINT); /* gsize -> guint */
    g_value_set_uint(val, (guint)self->max_block_size);

    if (surety)
	*surety = PROPERTY_SURETY_GOOD;

    if (source)
	*source = PROPERTY_SOURCE_DEFAULT;

    return TRUE;
}

static gboolean
property_get_canonical_name_fn(
	Device *self,
	DevicePropertyBase *base G_GNUC_UNUSED,
	GValue *val,
	PropertySurety *surety,
	PropertySource *source)
{
    g_value_unset_init(val, G_TYPE_STRING);
    g_value_set_string(val, self->device_name);

    if (surety)
	*surety = PROPERTY_SURETY_GOOD;

    if (source)
	*source = PROPERTY_SOURCE_DEFAULT;

    return TRUE;
}

/* util function */
static PropertyPhaseFlags
state_to_phase(
    Device *self)
{
    if (self->access_mode == ACCESS_NULL) {
	return PROPERTY_PHASE_BEFORE_START;
    } else if (IS_WRITABLE_ACCESS_MODE(self->access_mode)) {
	if (self->in_file) {
	    return PROPERTY_PHASE_INSIDE_FILE_WRITE;
	} else {
	    return PROPERTY_PHASE_BETWEEN_FILE_WRITE;
	}
    } else { /* read mode */
	if (self->in_file) {
	    return PROPERTY_PHASE_INSIDE_FILE_READ;
	} else {
	    return PROPERTY_PHASE_BETWEEN_FILE_READ;
	}
    }
}

/* This default implementation serves up static responses, and
   implements a few default responses based on values from the Device
   struct. */
static gboolean
default_device_property_get_ex(
	Device * self,
	DevicePropertyId id,
	GValue * val,
	PropertySurety *surety,
	PropertySource *source)
{
    DeviceProperty *prop;
    GArray *class_properties;
    PropertyPhaseFlags cur_phase;

    /* Most of this function's job is to sanity-check everything, then
     * call the relevant getter. */

    if (device_in_error(self))
	return FALSE;

    class_properties = DEVICE_GET_CLASS(self)->class_properties;
    if (id >= class_properties->len)
	return FALSE;

    prop = &g_array_index(class_properties, DeviceProperty, id);
    if (prop->base == NULL)
	return FALSE;

    if (val || surety || source) {
	/* check the phase */
	cur_phase = state_to_phase(self);
	if (!(prop->access & cur_phase))
	    return FALSE;

	if (prop->getter == NULL)
	    return FALSE;

	if (!prop->getter(self, prop->base, val, surety, source))
	    return FALSE;
    }

    return TRUE;
}

static gboolean
default_device_property_set_ex(
    Device *self,
    DevicePropertyId id,
    GValue * val,
    PropertySurety surety,
    PropertySource source)
{
    DeviceProperty *prop;
    GArray *class_properties;
    PropertyPhaseFlags cur_phase;

    /* Most of this function's job is to sanity-check everything, then
     * call the relevant setter. */

    if (device_in_error(self))
	return FALSE;

    class_properties = DEVICE_GET_CLASS(self)->class_properties;
    if (id >= class_properties->len)
	return FALSE;

    prop = &g_array_index(class_properties, DeviceProperty, id);
    if (prop->base == NULL)
	return FALSE;

    /* check that the type matches */
    if (!G_VALUE_HOLDS(val, prop->base->type))
	return FALSE;

    /* check the phase */
    cur_phase = state_to_phase(self) << PROPERTY_PHASE_SHIFT;
    if (!(prop->access & cur_phase))
	return FALSE;

    if (prop->setter == NULL)
	return FALSE;

    if (!prop->setter(self, prop->base, val, surety, source))
	return FALSE;

    return TRUE;
}

const GSList *
device_property_get_list (Device * self)
{
    g_assert(IS_DEVICE(self));

    return DEVICE_GET_CLASS(self)->class_properties_list;
}

static gboolean
default_device_read_to_fd(Device *self, queue_fd_t *queue_fd) {
    GValue val;
    StreamingRequirement streaming_mode;

    if (device_in_error(self)) return FALSE;

    /* Get the device's parameters */
    bzero(&val, sizeof(val));
    if (!device_property_get(self, PROPERTY_STREAMING, &val)
	|| !G_VALUE_HOLDS(&val, STREAMING_REQUIREMENT_TYPE)) {
	streaming_mode = STREAMING_REQUIREMENT_REQUIRED;
    } else {
	streaming_mode = g_value_get_enum(&val);
    }

    return QUEUE_SUCCESS ==
	do_consumer_producer_queue_full(
	    device_read_producer,
	    self,
	    fd_write_consumer,
	    queue_fd,
	    self->block_size,
	    DEFAULT_MAX_BUFFER_MEMORY,
	    streaming_mode);
}

static gboolean
default_device_write_from_fd(Device *self, queue_fd_t *queue_fd) {
    GValue val;
    StreamingRequirement streaming_mode;

    if (device_in_error(self)) return FALSE;

    /* Get the device's parameters */
    bzero(&val, sizeof(val));
    if (!device_property_get(self, PROPERTY_STREAMING, &val)
	|| !G_VALUE_HOLDS(&val, STREAMING_REQUIREMENT_TYPE)) {
	streaming_mode = STREAMING_REQUIREMENT_REQUIRED;
    } else {
	streaming_mode = g_value_get_enum(&val);
    }

    return QUEUE_SUCCESS ==
	do_consumer_producer_queue_full(
	    fd_read_producer,
	    queue_fd,
	    device_write_consumer,
	    self,
	    self->block_size,
	    DEFAULT_MAX_BUFFER_MEMORY,
	    streaming_mode);
}

/* XXX WARNING XXX
 * All the functions below this comment are stub functions that do nothing
 * but implement the virtual function table. Call these functions and they
 * will do what you expect vis-a-vis virtual functions. But don't put code
 * in them beyond error checking and VFT lookup. */

void
device_open_device (Device * self, char * device_name,
	char * device_type, char * device_node)
{
    DeviceClass *klass;

    g_assert(IS_DEVICE(self));
    g_assert(device_name != NULL);

    klass = DEVICE_GET_CLASS(self);
    g_assert(klass->open_device);
    (klass->open_device)(self, device_name, device_type, device_node);
}

DeviceStatusFlags device_read_label(Device * self) {
    DeviceClass * klass;

    g_assert(self != NULL);
    g_assert(IS_DEVICE(self));
    g_assert(self->access_mode == ACCESS_NULL);

    klass = DEVICE_GET_CLASS(self);
    g_assert(klass->read_label);
    return (klass->read_label)(self);
}

gboolean
device_finish (Device * self) {
    DeviceClass *klass;

    g_assert(IS_DEVICE (self));

    klass = DEVICE_GET_CLASS(self);
    g_assert(klass->finish);
    return (klass->finish)(self);
}

gboolean
device_configure (Device * self, gboolean use_global_config)
{
    DeviceClass *klass;

    g_assert(IS_DEVICE (self));
    g_assert(self->access_mode == ACCESS_NULL);

    klass = DEVICE_GET_CLASS(self);
    if(klass->configure) {
	return (klass->configure)(self, use_global_config);
    } else {
	device_set_error(self,
	    stralloc(_("Unimplemented method")),
	    DEVICE_STATUS_DEVICE_ERROR);
	return FALSE;
    }
}

gboolean 
device_start (Device * self, DeviceAccessMode mode,
              char * label, char * timestamp)
{
    DeviceClass *klass;
    char * local_timestamp = NULL;
    gboolean rv;

    g_assert(IS_DEVICE (self));
    g_assert(mode != ACCESS_NULL);
    g_assert(mode != ACCESS_WRITE || label != NULL);

    klass = DEVICE_GET_CLASS(self);
    g_assert(klass->start);

    /* For a good combination of synchronization and public simplicity,
       this stub function does not require a timestamp, but the actual
       implementation function does. We generate the timestamp here with
       time(). */
    if (mode == ACCESS_WRITE &&
	get_timestamp_state(timestamp) == TIME_STATE_REPLACE) {
	local_timestamp = timestamp =
	    get_proper_stamp_from_time(time(NULL));
    }

    rv = (klass->start)(self, mode, label, timestamp);
    amfree(local_timestamp);
    return rv;
}

gboolean
device_write_block (Device * self, guint size, gpointer block)
{
    DeviceClass *klass;

    g_assert(IS_DEVICE (self));
    g_assert(size > 0);

    /* these are all things that the caller should take care to
     * guarantee, so we just assert them here */
    g_assert(size <= self->block_size);
    g_assert(self->in_file);
    g_assert(!selfp->wrote_short_block);
    g_assert(block != NULL);
    g_assert(IS_WRITABLE_ACCESS_MODE(self->access_mode));

    if (size < self->block_size)
	selfp->wrote_short_block = TRUE;

    klass = DEVICE_GET_CLASS(self);
    g_assert(klass->write_block);
    return (*klass->write_block)(self,size, block);
}

gboolean 
device_write_from_fd (Device * self, queue_fd_t * queue_fd)
{
    DeviceClass *klass;

    g_assert(IS_DEVICE (self));
    g_assert(queue_fd->fd >= 0);
    g_assert(IS_WRITABLE_ACCESS_MODE(self->access_mode));

    klass = DEVICE_GET_CLASS(self);
    g_assert(klass->write_from_fd);
    return (klass->write_from_fd)(self,queue_fd);
}

gboolean
device_start_file (Device * self, dumpfile_t * jobInfo) {
    DeviceClass * klass;

    g_assert(IS_DEVICE (self));
    g_assert(!(self->in_file));
    g_assert(jobInfo != NULL);

    selfp->wrote_short_block = FALSE;

    klass = DEVICE_GET_CLASS(self);
    g_assert(klass->start_file);
    return (klass->start_file)(self, jobInfo );
}

gboolean 
device_finish_file (Device * self)
{
    DeviceClass *klass;

    g_assert(IS_DEVICE (self));
    g_assert(IS_WRITABLE_ACCESS_MODE(self->access_mode));
    g_assert(self->in_file);

    klass = DEVICE_GET_CLASS(self);
    g_assert(klass->finish_file);
    return (klass->finish_file)(self);
}

dumpfile_t*
device_seek_file (Device * self, guint file)
{
    DeviceClass *klass;

    g_assert(IS_DEVICE (self));
    g_assert(self->access_mode == ACCESS_READ);

    klass = DEVICE_GET_CLASS(self);
    g_assert(klass->seek_file);
    return (klass->seek_file)(self,file);
}

gboolean 
device_seek_block (Device * self, guint64 block)
{
    DeviceClass *klass;

    g_assert(IS_DEVICE (self));
    g_assert(self->access_mode == ACCESS_READ);
    g_assert(self->in_file);

    klass = DEVICE_GET_CLASS(self);
    g_assert(klass->seek_block);
    return (klass->seek_block)(self,block);
}

int
device_read_block (Device * self, gpointer buffer, int * size)
{
    DeviceClass *klass;

    g_assert(IS_DEVICE (self));
    g_assert(size != NULL);
    g_assert(self->access_mode == ACCESS_READ);

    if (*size != 0) {
	g_assert(buffer != NULL);
    }

    klass = DEVICE_GET_CLASS(self);
    g_assert(klass->read_block);
    return (klass->read_block)(self,buffer,size);
}

gboolean 
device_read_to_fd (Device * self, queue_fd_t *queue_fd)
{
    DeviceClass *klass;

    g_assert(IS_DEVICE (self));
    g_assert(queue_fd->fd >= 0);
    g_assert(self->access_mode == ACCESS_READ);

    klass = DEVICE_GET_CLASS(self);
    g_assert(klass->read_to_fd);
    return (klass->read_to_fd)(self,queue_fd);
}


gboolean 
device_property_get_ex(
	Device * self,
	DevicePropertyId id,
	GValue * val,
	PropertySurety *surety,
	PropertySource *source)
{
    DeviceClass *klass;

    g_assert(IS_DEVICE (self));
    g_assert(device_property_get_by_id(id) != NULL);

    klass = DEVICE_GET_CLASS(self);

    g_assert(klass->property_get_ex);
    return (klass->property_get_ex)(self, id, val, surety, source);
}

gboolean
device_property_set_ex(
	Device * self,
	DevicePropertyId id,
	GValue * val,
	PropertySurety surety,
	PropertySource source)
{
    DeviceClass *klass;

    g_assert(IS_DEVICE (self));

    klass = DEVICE_GET_CLASS(self);

    g_assert(klass->property_set_ex);
    return (klass->property_set_ex)(self, id, val, surety, source);
}

gboolean 
device_recycle_file (Device * self, guint filenum)
{
    DeviceClass *klass;

    g_assert(self != NULL);
    g_assert(IS_DEVICE (self));
    g_assert(self->access_mode == ACCESS_APPEND);
    g_assert(!self->in_file);

    klass = DEVICE_GET_CLASS(self);

    g_assert(klass->recycle_file);
    return (klass->recycle_file)(self,filenum);
}

/* Property handling */

void
device_class_register_property(
	DeviceClass *klass,
	DevicePropertyId id,
	PropertyAccessFlags access,
	PropertyGetFn getter,
	PropertySetFn setter)
{
    DevicePropertyBase *base;
    DeviceProperty *prop;
    GSList *proplist;
    guint i;

    g_assert(klass != NULL);

    base = device_property_get_by_id(id);
    g_assert(base != NULL);

    if (klass->class_properties->len <= id) {
	g_array_set_size(klass->class_properties, id+1);
    }

    prop = &g_array_index(klass->class_properties, DeviceProperty, id);
    prop->base = base;
    prop->access = access;
    prop->getter = getter;
    prop->setter = setter;

    /* completely rewrite the list of prop pointers, as they may have changed,
     * or we may have replaced an existing property*/

    if (klass->class_properties_list) {
	g_slist_free(klass->class_properties_list);
    }

    proplist = NULL;
    for (i = 0; i < klass->class_properties->len; i++) {
	prop = &g_array_index(klass->class_properties, DeviceProperty, i);
	if (!prop->base)
	    continue;
	proplist = g_slist_prepend(proplist, prop);
    }

    klass->class_properties_list = proplist;
}

gboolean
device_set_simple_property(
	Device *self,
	DevicePropertyId id,
	GValue *val,
	PropertySurety surety,
	PropertySource source)
{
    SimpleProperty *simp;
    DeviceProperty *prop;

    prop = &g_array_index(DEVICE_GET_CLASS(self)->class_properties,
			  DeviceProperty, id);

    /* these assertions should already be checked, but let's be sure */
    g_assert(prop->base != NULL);   /* prop must be registered with device */
    g_assert(G_VALUE_HOLDS(val, prop->base->type));

    simp = g_new0(SimpleProperty, 1);
    simp->prop = prop;
    g_value_unset_copy(val, &(simp->response));
    simp->surety = surety;
    simp->source = source;

    g_hash_table_insert(selfp->simple_properties,
			GINT_TO_POINTER(id),
			simp);

    return TRUE;
}

gboolean
device_simple_property_set_fn(
	Device *self,
	DevicePropertyBase *base,
	GValue *val,
	PropertySurety surety,
	PropertySource source)
{
    return device_set_simple_property(self, base->ID, val, surety, source);
}

gboolean
device_get_simple_property(
	Device *self,
	DevicePropertyId id,
	GValue *val,
	PropertySurety *surety,
	PropertySource *source)
{
    SimpleProperty *simp =
	g_hash_table_lookup(selfp->simple_properties,
			    GINT_TO_POINTER(id));

    if (!simp)
	return FALSE;

    if (val)
	g_value_unset_copy(&(simp->response), val);

    if (surety)
	*surety = simp->surety;

    if (source)
	*source = simp->source;

    return TRUE;
}

gboolean
device_simple_property_get_fn(
	Device *self,
	DevicePropertyBase *base,
	GValue *val,
	PropertySurety *surety,
	PropertySource *source)
{
    return device_get_simple_property(self, base->ID, val, surety, source);
}