git.gag.com Git - debian/amanda/blob - device-src/tape-device.c

   1 /*
   2  * Copyright (c) 2007, 2008, 2009, 2010 Zmanda, Inc.  All Rights Reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or modify it
   5  * under the terms of the GNU General Public License version 2 as published
   6  * by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  10  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  11  * for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License along
  14  * with this program; if not, write to the Free Software Foundation, Inc.,
  15  * 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  16  *
  17  * Contact information: Zmanda Inc., 465 S. Mathilda Ave., Suite 300
  18  * Sunnyvale, CA 94085, USA, or: http://www.zmanda.com
  19  */
  20
  21 #include "amanda.h"
  22 #include "pipespawn.h"
  23 #include <string.h> /* memset() */
  24 #include "util.h"
  25 #include "device.h"
  26
  27 #ifdef HAVE_SYS_TAPE_H
  28 # include <sys/tape.h>
  29 #endif
  30 #ifdef HAVE_SYS_MTIO_H
  31 # include <sys/mtio.h>
  32 #endif
  33 #ifdef HAVE_LIMITS_H
  34 # include <limits.h>
  35 #endif
  36
  37 /* This is equal to 2*1024*1024*1024 - 16*1024*1024 - 1, but written
  38    explicitly to avoid overflow issues. */
  39 #define RESETOFS_THRESHOLD (0x7effffff)
  40
  41 /* Largest possible block size on SCSI systems. */
  42 #define LARGEST_BLOCK_ESTIMATE (16 * 1024 * 1024)
  43
  44 /*
  45  * Type checking and casting macros
  46  */
  47
  48 #define TYPE_TAPE_DEVICE        (tape_device_get_type())
  49 #define TAPE_DEVICE(obj)        G_TYPE_CHECK_INSTANCE_CAST((obj), tape_device_get_type(), TapeDevice)
  50 #define TAPE_DEVICE_CONST(obj)  G_TYPE_CHECK_INSTANCE_CAST((obj), tape_device_get_type(), TapeDevice const)
  51 #define TAPE_DEVICE_CLASS(klass)        G_TYPE_CHECK_CLASS_CAST((klass), tape_device_get_type(), TapeDeviceClass)
  52 #define IS_TAPE_DEVICE(obj)     G_TYPE_CHECK_INSTANCE_TYPE((obj), tape_device_get_type ())
  53 #define TAPE_DEVICE_GET_CLASS(obj)      G_TYPE_INSTANCE_GET_CLASS((obj), tape_device_get_type(), TapeDeviceClass)
  54 GType   tape_device_get_type    (void);
  55
  56 /*
  57  * Main object structure
  58  */
  59 typedef struct TapeDevicePrivate_s TapeDevicePrivate;
  60 typedef struct _TapeDevice {
  61     Device __parent__;
  62
  63     /* It should go without saying that all this stuff is
  64      * look-but-don't-touch. */
  65
  66     /* characteristics of the device */
  67     gboolean fsf, bsf, fsr, bsr, eom, bsf_after_eom, broken_gmt_online;
  68     gboolean leom;
  69     gboolean nonblocking_open, fsf_after_filemark;
  70     int final_filemarks;
  71
  72     /* 0 if we opened with O_RDWR; error otherwise. */
  73     gboolean write_open_errno;
  74     int fd;
  75
  76     TapeDevicePrivate * private;
  77 } TapeDevice;
  78
  79 struct TapeDevicePrivate_s {
  80     /* This holds the total number of bytes written to the device,
  81        modulus RESETOFS_THRESHOLD. */
  82     int write_count;
  83     char * device_filename;
  84     gsize read_block_size;
  85 };
  86
  87 /*
  88  * Class definition
  89  */
  90
  91 typedef struct _TapeDeviceClass TapeDeviceClass;
  92 struct _TapeDeviceClass {
  93         DeviceClass __parent__;
  94 };
  95
  96 void tape_device_register(void);
  97
  98 /* useful callback for tape ops */
  99 void tape_device_set_capabilities(TapeDevice *self,
 100         gboolean fsf, PropertySurety fsf_surety, PropertySource fsf_source,
 101         gboolean fsf_after_filemark, PropertySurety faf_surety, PropertySource faf_source,
 102         gboolean bsf, PropertySurety bsf_surety, PropertySource bsf_source,
 103         gboolean fsr, PropertySurety fsr_surety, PropertySource fsr_source,
 104         gboolean bsr, PropertySurety bsr_surety, PropertySource bsr_source,
 105         gboolean eom, PropertySurety eom_surety, PropertySource eom_source,
 106         gboolean leom, PropertySurety leom_surety, PropertySource leom_source,
 107         gboolean bsf_after_eom, PropertySurety bae_surety, PropertySource bae_source,
 108         guint final_filemarks, PropertySurety ff_surety, PropertySource ff_source);
 109
 110 /* Real Operations (always return FALSE if not implemented) */
 111 gboolean tape_rewind(int fd);
 112 gboolean tape_fsf(int fd, guint count);
 113 gboolean tape_bsf(int fd, guint count);
 114 gboolean tape_fsr(int fd, guint count);
 115 gboolean tape_bsr(int fd, guint count);
 116 gint tape_fileno(int fd);
 117
 118 /* tape_fileno returns tape position file number, or one of these: */
 119 #define TAPE_OP_ERROR -1
 120 #define TAPE_POSITION_UNKNOWN -2
 121
 122 /* Possible (abstracted) results from a system I/O operation. */
 123 typedef enum {
 124     RESULT_SUCCESS,
 125     RESULT_ERROR,        /* Undefined error (*errmsg set) */
 126     RESULT_SMALL_BUFFER, /* Tried to read with a buffer that is too
 127                             small. */
 128     RESULT_NO_DATA,      /* End of File, while reading */
 129     RESULT_NO_SPACE,     /* Out of space. Sometimes we don't know if
 130                             it was this or I/O error, but this is the
 131                             preferred explanation. */
 132     RESULT_MAX
 133 } IoResult;
 134
 135 /* returns a fileno like tape_fileno */
 136 gint tape_eod(int fd);
 137
 138 gboolean tape_weof(int fd, guint8 count);
 139 gboolean tape_setcompression(int fd, gboolean on);
 140
 141 gboolean tape_offl(int fd);
 142
 143 DeviceStatusFlags tape_is_tape_device(int fd);
 144 DeviceStatusFlags tape_is_ready(int fd, TapeDevice *t_self);
 145
 146 #define tape_device_read_size(self) \
 147     (((TapeDevice *)(self))->private->read_block_size? \
 148         ((TapeDevice *)(self))->private->read_block_size : ((Device *)(self))->block_size)
 149
 150 /*
 151  * Our device-specific properties.
 152  */
 153
 154 #define PROPERTY_BROKEN_GMT_ONLINE (device_property_broken_gmt_online.ID)
 155 #define PROPERTY_FSF (device_property_fsf.ID)
 156 #define PROPERTY_FSF_AFTER_FILEMARK (device_property_fsf_after_filemark.ID)
 157 #define PROPERTY_BSF (device_property_bsf.ID)
 158 #define PROPERTY_FSR (device_property_fsr.ID)
 159 #define PROPERTY_BSR (device_property_bsr.ID)
 160 #define PROPERTY_EOM (device_property_eom.ID)
 161 #define PROPERTY_BSF_AFTER_EOM (device_property_bsf_after_eom.ID)
 162 #define PROPERTY_NONBLOCKING_OPEN (device_property_nonblocking_open.ID)
 163 #define PROPERTY_FINAL_FILEMARKS (device_property_final_filemarks.ID)
 164
 165 static DevicePropertyBase device_property_broken_gmt_online;
 166 static DevicePropertyBase device_property_fsf;
 167 static DevicePropertyBase device_property_fsf_after_filemark;
 168 static DevicePropertyBase device_property_bsf;
 169 static DevicePropertyBase device_property_fsr;
 170 static DevicePropertyBase device_property_bsr;
 171 static DevicePropertyBase device_property_eom;
 172 static DevicePropertyBase device_property_bsf_after_eom;
 173 static DevicePropertyBase device_property_nonblocking_open;
 174 static DevicePropertyBase device_property_final_filemarks;
 175 static DevicePropertyBase device_property_read_buffer_size; /* old name for READ_BLOCK_SIZE */
 176
 177 /* here are local prototypes */
 178 static void tape_device_init (TapeDevice * o);
 179 static void tape_device_class_init (TapeDeviceClass * c);
 180 static void tape_device_base_init (TapeDeviceClass * c);
 181 static gboolean tape_device_set_feature_property_fn(Device *p_self, DevicePropertyBase *base,
 182                                     GValue *val, PropertySurety surety, PropertySource source);
 183 static gboolean tape_device_set_final_filemarks_fn(Device *p_self, DevicePropertyBase *base,
 184                                     GValue *val, PropertySurety surety, PropertySource source);
 185 static gboolean tape_device_set_compression_fn(Device *p_self, DevicePropertyBase *base,
 186                                     GValue *val, PropertySurety surety, PropertySource source);
 187 static gboolean tape_device_get_read_block_size_fn(Device *p_self, DevicePropertyBase *base,
 188                                     GValue *val, PropertySurety *surety, PropertySource *source);
 189 static gboolean tape_device_set_read_block_size_fn(Device *p_self, DevicePropertyBase *base,
 190                                     GValue *val, PropertySurety surety, PropertySource source);
 191 static void tape_device_open_device (Device * self, char * device_name, char * device_type, char * device_node);
 192 static Device * tape_device_factory (char * device_name, char * device_type, char * device_node);
 193 static DeviceStatusFlags tape_device_read_label(Device * self);
 194 static gboolean tape_device_write_block(Device * self, guint size, gpointer data);
 195 static int tape_device_read_block(Device * self,  gpointer buf,
 196                                        int * size_req);
 197 static gboolean tape_device_start (Device * self, DeviceAccessMode mode,
 198                                    char * label, char * timestamp);
 199 static gboolean tape_device_start_file (Device * self, dumpfile_t * ji);
 200 static gboolean tape_device_finish_file (Device * self);
 201 static dumpfile_t * tape_device_seek_file (Device * self, guint file);
 202 static gboolean tape_device_seek_block (Device * self, guint64 block);
 203 static gboolean tape_device_eject (Device * self);
 204 static gboolean tape_device_finish (Device * self);
 205 static IoResult tape_device_robust_read (TapeDevice * self, void * buf,
 206                                                int * count, char **errmsg);
 207 static IoResult tape_device_robust_write (TapeDevice * self, void * buf, int count, char **errmsg);
 208 static gboolean tape_device_fsf (TapeDevice * self, guint count);
 209 static gboolean tape_device_fsr (TapeDevice * self, guint count);
 210 static gboolean tape_device_bsr (TapeDevice * self, guint count, guint file, guint block);
 211 static gboolean tape_device_eod (TapeDevice * self);
 212
 213 /* pointer to the class of our parent */
 214 static DeviceClass *parent_class = NULL;
 215
 216 GType tape_device_get_type (void)
 217 {
 218     static GType type = 0;
 219
 220     if G_UNLIKELY(type == 0) {
 221         static const GTypeInfo info = {
 222             sizeof (TapeDeviceClass),
 223             (GBaseInitFunc) tape_device_base_init,
 224             (GBaseFinalizeFunc) NULL,
 225             (GClassInitFunc) tape_device_class_init,
 226             (GClassFinalizeFunc) NULL,
 227             NULL /* class_data */,
 228             sizeof (TapeDevice),
 229             0 /* n_preallocs */,
 230             (GInstanceInitFunc) tape_device_init,
 231             NULL
 232         };
 233
 234         type = g_type_register_static (TYPE_DEVICE, "TapeDevice",
 235                                        &info, (GTypeFlags)0);
 236     }
 237
 238     return type;
 239 }
 240
 241 static void
 242 tape_device_init (TapeDevice * self) {
 243     Device * d_self;
 244     GValue response;
 245
 246     d_self = DEVICE(self);
 247     bzero(&response, sizeof(response));
 248
 249     self->private = g_new0(TapeDevicePrivate, 1);
 250
 251     /* Clear all fields. */
 252     d_self->block_size = 32768;
 253     d_self->min_block_size = 32768;
 254     d_self->max_block_size = LARGEST_BLOCK_ESTIMATE;
 255     self->broken_gmt_online = FALSE;
 256
 257     self->fd = -1;
 258
 259     /* set all of the feature properties to an unsure default of FALSE */
 260     self->broken_gmt_online = FALSE;
 261     self->fsf = FALSE;
 262     self->bsf = FALSE;
 263     self->fsr = FALSE;
 264     self->bsr = FALSE;
 265     self->eom = FALSE;
 266     self->leom = FALSE;
 267     self->bsf_after_eom = FALSE;
 268
 269     g_value_init(&response, G_TYPE_BOOLEAN);
 270     g_value_set_boolean(&response, FALSE);
 271     device_set_simple_property(d_self, PROPERTY_BROKEN_GMT_ONLINE,
 272             &response, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 273     device_set_simple_property(d_self, PROPERTY_FSF,
 274             &response, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 275     device_set_simple_property(d_self, PROPERTY_FSF_AFTER_FILEMARK,
 276             &response, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 277     device_set_simple_property(d_self, PROPERTY_BSF,
 278             &response, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 279     device_set_simple_property(d_self, PROPERTY_FSR,
 280             &response, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 281     device_set_simple_property(d_self, PROPERTY_BSR,
 282             &response, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 283     device_set_simple_property(d_self, PROPERTY_EOM,
 284             &response, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 285     device_set_simple_property(d_self, PROPERTY_LEOM,
 286             &response, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 287     device_set_simple_property(d_self, PROPERTY_BSF_AFTER_EOM,
 288             &response, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 289
 290 #ifdef DEFAULT_TAPE_NON_BLOCKING_OPEN
 291     self->nonblocking_open = TRUE;
 292 #else
 293     self->nonblocking_open = FALSE;
 294 #endif
 295     g_value_set_boolean(&response, self->nonblocking_open);
 296     device_set_simple_property(d_self, PROPERTY_NONBLOCKING_OPEN,
 297             &response, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 298     g_value_unset(&response);
 299
 300     self->final_filemarks = 2;
 301     g_value_init(&response, G_TYPE_UINT);
 302     g_value_set_uint(&response, self->final_filemarks);
 303     device_set_simple_property(d_self, PROPERTY_FINAL_FILEMARKS,
 304             &response, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 305     g_value_unset(&response);
 306
 307     self->private->read_block_size = 0;
 308     g_value_init(&response, G_TYPE_UINT);
 309     g_value_set_uint(&response, self->private->read_block_size);
 310     device_set_simple_property(d_self, PROPERTY_READ_BLOCK_SIZE,
 311             &response, PROPERTY_SURETY_GOOD, PROPERTY_SOURCE_DEFAULT);
 312     g_value_unset(&response);
 313
 314     self->private->write_count = 0;
 315     self->private->device_filename = NULL;
 316
 317     /* Static properites */
 318     g_value_init(&response, CONCURRENCY_PARADIGM_TYPE);
 319     g_value_set_enum(&response, CONCURRENCY_PARADIGM_EXCLUSIVE);
 320     device_set_simple_property(d_self, PROPERTY_CONCURRENCY,
 321             &response, PROPERTY_SURETY_GOOD, PROPERTY_SOURCE_DETECTED);
 322     g_value_unset(&response);
 323
 324     g_value_init(&response, STREAMING_REQUIREMENT_TYPE);
 325     g_value_set_enum(&response, STREAMING_REQUIREMENT_DESIRED);
 326     device_set_simple_property(d_self, PROPERTY_STREAMING,
 327             &response, PROPERTY_SURETY_GOOD, PROPERTY_SOURCE_DETECTED);
 328     g_value_unset(&response);
 329
 330     g_value_init(&response, G_TYPE_BOOLEAN);
 331     g_value_set_boolean(&response, TRUE);
 332     device_set_simple_property(d_self, PROPERTY_APPENDABLE,
 333             &response, PROPERTY_SURETY_GOOD, PROPERTY_SOURCE_DETECTED);
 334     g_value_unset(&response);
 335
 336     g_value_init(&response, G_TYPE_BOOLEAN);
 337     g_value_set_boolean(&response, FALSE);
 338     device_set_simple_property(d_self, PROPERTY_PARTIAL_DELETION,
 339             &response, PROPERTY_SURETY_GOOD, PROPERTY_SOURCE_DETECTED);
 340     g_value_unset(&response);
 341
 342     g_value_init(&response, G_TYPE_BOOLEAN);
 343     g_value_set_boolean(&response, FALSE);
 344     device_set_simple_property(d_self, PROPERTY_FULL_DELETION,
 345             &response, PROPERTY_SURETY_GOOD, PROPERTY_SOURCE_DETECTED);
 346     g_value_unset(&response);
 347
 348     g_value_init(&response, MEDIA_ACCESS_MODE_TYPE);
 349     g_value_set_enum(&response, MEDIA_ACCESS_MODE_READ_WRITE);
 350     device_set_simple_property(d_self, PROPERTY_MEDIUM_ACCESS_TYPE,
 351             &response, PROPERTY_SURETY_GOOD, PROPERTY_SOURCE_DETECTED);
 352     g_value_unset(&response);
 353 }
 354
 355 static void tape_device_finalize(GObject * obj_self) {
 356     TapeDevice * self = TAPE_DEVICE(obj_self);
 357
 358     if(G_OBJECT_CLASS(parent_class)->finalize) \
 359            (* G_OBJECT_CLASS(parent_class)->finalize)(obj_self);
 360
 361     robust_close(self->fd);
 362     self->fd = -1;
 363     amfree(self->private->device_filename);
 364     amfree(self->private);
 365 }
 366
 367 static void
 368 tape_device_class_init (TapeDeviceClass * c)
 369 {
 370     DeviceClass *device_class = (DeviceClass *)c;
 371     GObjectClass *g_object_class = (GObjectClass *)c;
 372
 373     parent_class = g_type_class_ref (TYPE_DEVICE);
 374
 375     device_class->open_device = tape_device_open_device;
 376     device_class->read_label = tape_device_read_label;
 377     device_class->write_block = tape_device_write_block;
 378     device_class->read_block = tape_device_read_block;
 379     device_class->start = tape_device_start;
 380     device_class->start_file = tape_device_start_file;
 381     device_class->finish_file = tape_device_finish_file;
 382     device_class->seek_file = tape_device_seek_file;
 383     device_class->seek_block = tape_device_seek_block;
 384     device_class->eject = tape_device_eject;
 385     device_class->finish = tape_device_finish;
 386
 387     g_object_class->finalize = tape_device_finalize;
 388 }
 389
 390 static void
 391 tape_device_base_init (TapeDeviceClass * c)
 392 {
 393     DeviceClass *device_class = (DeviceClass *)c;
 394
 395     device_class_register_property(device_class, PROPERTY_BROKEN_GMT_ONLINE,
 396             PROPERTY_ACCESS_GET_MASK | PROPERTY_ACCESS_SET_BEFORE_START,
 397             device_simple_property_get_fn,
 398             tape_device_set_feature_property_fn);
 399
 400     device_class_register_property(device_class, PROPERTY_FSF,
 401             PROPERTY_ACCESS_GET_MASK | PROPERTY_ACCESS_SET_BEFORE_START,
 402             device_simple_property_get_fn,
 403             tape_device_set_feature_property_fn);
 404
 405     device_class_register_property(device_class, PROPERTY_FSF_AFTER_FILEMARK,
 406             PROPERTY_ACCESS_GET_MASK | PROPERTY_ACCESS_SET_BEFORE_START,
 407             device_simple_property_get_fn,
 408             tape_device_set_feature_property_fn);
 409
 410     device_class_register_property(device_class, PROPERTY_BSF,
 411             PROPERTY_ACCESS_GET_MASK | PROPERTY_ACCESS_SET_BEFORE_START,
 412             device_simple_property_get_fn,
 413             tape_device_set_feature_property_fn);
 414
 415     device_class_register_property(device_class, PROPERTY_FSR,
 416             PROPERTY_ACCESS_GET_MASK | PROPERTY_ACCESS_SET_BEFORE_START,
 417             device_simple_property_get_fn,
 418             tape_device_set_feature_property_fn);
 419
 420     device_class_register_property(device_class, PROPERTY_BSR,
 421             PROPERTY_ACCESS_GET_MASK | PROPERTY_ACCESS_SET_BEFORE_START,
 422             device_simple_property_get_fn,
 423             tape_device_set_feature_property_fn);
 424
 425     device_class_register_property(device_class, PROPERTY_EOM,
 426             PROPERTY_ACCESS_GET_MASK | PROPERTY_ACCESS_SET_BEFORE_START,
 427             device_simple_property_get_fn,
 428             tape_device_set_feature_property_fn);
 429
 430     device_class_register_property(device_class, PROPERTY_BSF_AFTER_EOM,
 431             PROPERTY_ACCESS_GET_MASK | PROPERTY_ACCESS_SET_BEFORE_START,
 432             device_simple_property_get_fn,
 433             tape_device_set_feature_property_fn);
 434
 435     device_class_register_property(device_class, PROPERTY_NONBLOCKING_OPEN,
 436             PROPERTY_ACCESS_GET_MASK | PROPERTY_ACCESS_SET_BEFORE_START,
 437             device_simple_property_get_fn,
 438             tape_device_set_feature_property_fn);
 439
 440     device_class_register_property(device_class, PROPERTY_FINAL_FILEMARKS,
 441             PROPERTY_ACCESS_GET_MASK | PROPERTY_ACCESS_SET_BEFORE_START,
 442             device_simple_property_get_fn,
 443             tape_device_set_final_filemarks_fn);
 444
 445     /* We don't (yet?) support reading the device's compression state, so not
 446      * gettable. */
 447     device_class_register_property(device_class, PROPERTY_COMPRESSION,
 448             PROPERTY_ACCESS_SET_MASK,
 449             NULL,
 450             tape_device_set_compression_fn);
 451
 452     device_class_register_property(device_class, PROPERTY_READ_BLOCK_SIZE,
 453             PROPERTY_ACCESS_GET_MASK | PROPERTY_ACCESS_SET_BEFORE_START,
 454             tape_device_get_read_block_size_fn,
 455             tape_device_set_read_block_size_fn);
 456
 457     device_class_register_property(device_class, device_property_read_buffer_size.ID,
 458             PROPERTY_ACCESS_GET_MASK | PROPERTY_ACCESS_SET_BEFORE_START,
 459             tape_device_get_read_block_size_fn,
 460             tape_device_set_read_block_size_fn);
 461
 462     /* add the ability to set LEOM to FALSE, for testing purposes */
 463     device_class_register_property(device_class, PROPERTY_LEOM,
 464             PROPERTY_ACCESS_GET_MASK | PROPERTY_ACCESS_SET_BEFORE_START,
 465             device_simple_property_get_fn,
 466             tape_device_set_feature_property_fn);
 467 }
 468
 469 static gboolean
 470 tape_device_set_feature_property_fn(Device *p_self, DevicePropertyBase *base,
 471     GValue *val, PropertySurety surety, PropertySource source)
 472 {
 473     TapeDevice *self = TAPE_DEVICE(p_self);
 474     GValue old_val;
 475     gboolean old_bool, new_bool;
 476     PropertySurety old_surety;
 477     PropertySource old_source;
 478
 479     new_bool = g_value_get_boolean(val);
 480
 481     /* get the old source and surety and see if we're willing to make this change */
 482     bzero(&old_val, sizeof(old_val));
 483     if (device_get_simple_property(p_self, base->ID, &old_val, &old_surety, &old_source)) {
 484         old_bool = g_value_get_boolean(&old_val);
 485
 486         if (old_surety == PROPERTY_SURETY_GOOD && old_source == PROPERTY_SOURCE_DETECTED) {
 487             if (new_bool != old_bool) {
 488                 device_set_error(p_self, vstrallocf(_(
 489                            "Value for property '%s' was autodetected and cannot be changed"),
 490                            base->name),
 491                     DEVICE_STATUS_DEVICE_ERROR);
 492                 return FALSE;
 493             } else {
 494                 /* pretend we set it, but don't change surety/source */
 495                 return TRUE;
 496             }
 497         }
 498     }
 499
 500     /* (note: PROPERTY_* are not constants, so we can't use switch) */
 501     if (base->ID == PROPERTY_BROKEN_GMT_ONLINE)
 502         self->broken_gmt_online = new_bool;
 503     else if (base->ID == PROPERTY_FSF)
 504         self->fsf = new_bool;
 505     else if (base->ID == PROPERTY_FSF_AFTER_FILEMARK)
 506         self->fsf_after_filemark = new_bool;
 507     else if (base->ID == PROPERTY_BSF)
 508         self->bsf = new_bool;
 509     else if (base->ID == PROPERTY_FSR)
 510         self->fsr = new_bool;
 511     else if (base->ID == PROPERTY_BSR)
 512         self->bsr = new_bool;
 513     else if (base->ID == PROPERTY_EOM)
 514         self->eom = new_bool;
 515     else if (base->ID == PROPERTY_BSF_AFTER_EOM)
 516         self->bsf_after_eom = new_bool;
 517     else if (base->ID == PROPERTY_NONBLOCKING_OPEN)
 518         self->nonblocking_open = new_bool;
 519     else if (base->ID == PROPERTY_LEOM)
 520         self->leom = new_bool;
 521     else
 522         return FALSE; /* shouldn't happen */
 523
 524     return device_simple_property_set_fn(p_self, base, val, surety, source);
 525 }
 526
 527 static gboolean
 528 tape_device_set_final_filemarks_fn(Device *p_self, DevicePropertyBase *base,
 529     GValue *val, PropertySurety surety, PropertySource source)
 530 {
 531     TapeDevice *self = TAPE_DEVICE(p_self);
 532     GValue old_val;
 533     gboolean old_int, new_int;
 534     PropertySurety old_surety;
 535     PropertySource old_source;
 536
 537     new_int = g_value_get_uint(val);
 538
 539     /* get the old source and surety and see if we're willing to make this change */
 540     bzero(&old_val, sizeof(old_val));
 541     if (device_get_simple_property(p_self, base->ID, &old_val, &old_surety, &old_source)) {
 542         old_int = g_value_get_uint(&old_val);
 543
 544         if (old_surety == PROPERTY_SURETY_GOOD && old_source == PROPERTY_SOURCE_DETECTED) {
 545             if (new_int != old_int) {
 546                 device_set_error(p_self, vstrallocf(_(
 547                            "Value for property '%s' was autodetected and cannot be changed"),
 548                            base->name),
 549                     DEVICE_STATUS_DEVICE_ERROR);
 550                 return FALSE;
 551             } else {
 552                 /* pretend we set it, but don't change surety/source */
 553                 return TRUE;
 554             }
 555         }
 556     }
 557
 558     self->final_filemarks = new_int;
 559
 560     return device_simple_property_set_fn(p_self, base, val, surety, source);
 561 }
 562
 563 static gboolean
 564 tape_device_set_compression_fn(Device *p_self, DevicePropertyBase *base,
 565     GValue *val, PropertySurety surety, PropertySource source)
 566 {
 567     TapeDevice *self = TAPE_DEVICE(p_self);
 568     gboolean request = g_value_get_boolean(val);
 569
 570     /* We allow this property to be set at any time. This is mostly
 571      * because setting compression is a hit-and-miss proposition
 572      * at any time; some drives accept the mode setting but don't
 573      * actually support compression, while others do support
 574      * compression but do it via density settings or some other
 575      * way. Set this property whenever you want, but all we'll do
 576      * is report whether or not the ioctl succeeded. */
 577     if (tape_setcompression(self->fd, request)) {
 578         /* looks good .. let's start the device over, though */
 579         device_clear_volume_details(p_self);
 580     } else {
 581         device_set_error(p_self,
 582             g_strdup("Error setting COMPRESION property"),
 583             DEVICE_STATUS_DEVICE_ERROR);
 584         return FALSE;
 585     }
 586
 587     return device_simple_property_set_fn(p_self, base, val, surety, source);
 588 }
 589
 590 static gboolean
 591 tape_device_get_read_block_size_fn(Device *p_self, DevicePropertyBase *base G_GNUC_UNUSED,
 592     GValue *val, PropertySurety *surety, PropertySource *source)
 593 {
 594     /* use the READ_BLOCK_SIZE, even if we're invoked to get the old READ_BUFFER_SIZE */
 595     return device_simple_property_get_fn(p_self, &device_property_read_block_size,
 596                                         val, surety, source);
 597 }
 598
 599 static gboolean
 600 tape_device_set_read_block_size_fn(Device *p_self, DevicePropertyBase *base G_GNUC_UNUSED,
 601     GValue *val, PropertySurety surety, PropertySource source)
 602 {
 603     TapeDevice *self = TAPE_DEVICE(p_self);
 604     guint read_block_size = g_value_get_uint(val);
 605
 606     if (read_block_size != 0 &&
 607             ((gsize)read_block_size < p_self->block_size ||
 608              (gsize)read_block_size > p_self->max_block_size))
 609         device_set_error(p_self,
 610             g_strdup_printf("Error setting READ-BLOCk-SIZE property to '%u', it must be between %zu and %zu", read_block_size, p_self->block_size, p_self->max_block_size),
 611             DEVICE_STATUS_DEVICE_ERROR);
 612         return FALSE;
 613
 614     self->private->read_block_size = read_block_size;
 615
 616     /* use the READ_BLOCK_SIZE, even if we're invoked to get the old READ_BUFFER_SIZE */
 617     return device_simple_property_set_fn(p_self, &device_property_read_block_size,
 618                                         val, surety, source);
 619 }
 620
 621 void tape_device_register(void) {
 622     static const char * device_prefix_list[] = { "tape", NULL };
 623
 624     /* First register tape-specific properties */
 625     device_property_fill_and_register(&device_property_broken_gmt_online,
 626                                       G_TYPE_BOOLEAN, "broken_gmt_online",
 627       "Does this drive support the GMT_ONLINE macro?");
 628
 629     device_property_fill_and_register(&device_property_fsf,
 630                                       G_TYPE_BOOLEAN, "fsf",
 631       "Does this drive support the MTFSF command?");
 632
 633     device_property_fill_and_register(&device_property_fsf_after_filemark,
 634                                       G_TYPE_BOOLEAN, "fsf_after_filemark",
 635       "Does this drive needs a FSF if a filemark is already read?");
 636
 637     device_property_fill_and_register(&device_property_bsf,
 638                                       G_TYPE_BOOLEAN, "bsf",
 639       "Does this drive support the MTBSF command?" );
 640
 641     device_property_fill_and_register(&device_property_fsr,
 642                                       G_TYPE_BOOLEAN, "fsr",
 643       "Does this drive support the MTFSR command?");
 644
 645     device_property_fill_and_register(&device_property_bsr,
 646                                       G_TYPE_BOOLEAN, "bsr",
 647       "Does this drive support the MTBSR command?");
 648
 649     device_property_fill_and_register(&device_property_eom,
 650                                       G_TYPE_BOOLEAN, "eom",
 651       "Does this drive support the MTEOM command?");
 652
 653     device_property_fill_and_register(&device_property_bsf_after_eom,
 654                                       G_TYPE_BOOLEAN,
 655                                       "bsf_after_eom",
 656       "Does this drive require an MTBSF after MTEOM in order to append?" );
 657
 658     device_property_fill_and_register(&device_property_nonblocking_open,
 659                                       G_TYPE_BOOLEAN,
 660                                       "nonblocking_open",
 661       "Does this drive require a open with O_NONBLOCK?" );
 662
 663     device_property_fill_and_register(&device_property_final_filemarks,
 664                                       G_TYPE_UINT, "final_filemarks",
 665       "How many filemarks to write after the last tape file?" );
 666
 667     device_property_fill_and_register(&device_property_read_buffer_size,
 668                                       G_TYPE_UINT, "read_buffer_size",
 669       "(deprecated name for READ_BLOCK_SIZE)");
 670
 671     /* Then the device itself */
 672     register_device(tape_device_factory, device_prefix_list);
 673 }
 674
 675 /* Open the tape device, trying various combinations of O_RDWR and
 676    O_NONBLOCK.  Returns -1 and calls device_set_error for errors
 677    On Linux, with O_NONBLOCK, the kernel just checks the state once,
 678    whereas it checks it every second for ST_BLOCK_SECONDS if O_NONBLOCK is
 679    not given.  Amanda already have the code to poll, we want open to check
 680    the state only once. */
 681
 682 static int try_open_tape_device(TapeDevice * self, char * device_filename) {
 683     int fd;
 684     int save_errno;
 685     DeviceStatusFlags new_status;
 686
 687 #ifdef O_NONBLOCK
 688     int nonblocking = 0;
 689
 690     if (self->nonblocking_open) {
 691         nonblocking = O_NONBLOCK;
 692     }
 693 #endif
 694
 695 #ifdef O_NONBLOCK
 696     fd  = robust_open(device_filename, O_RDWR | nonblocking, 0);
 697     save_errno = errno;
 698     if (fd < 0 && nonblocking && (save_errno == EWOULDBLOCK || save_errno == EINVAL)) {
 699         /* Maybe we don't support O_NONBLOCK for tape devices. */
 700         fd = robust_open(device_filename, O_RDWR, 0);
 701         save_errno = errno;
 702     }
 703 #else
 704     fd = robust_open(device_filename, O_RDWR, 0);
 705     save_errno = errno;
 706 #endif
 707     if (fd >= 0) {
 708         self->write_open_errno = 0;
 709     } else {
 710         if (errno == EACCES || errno == EPERM
 711 #ifdef EROFS
 712                             || errno == EROFS
 713 #endif
 714            ) {
 715             /* Device is write-protected. */
 716             self->write_open_errno = errno;
 717 #ifdef O_NONBLOCK
 718             fd = robust_open(device_filename, O_RDONLY | nonblocking, 0);
 719             save_errno = errno;
 720             if (fd < 0 && nonblocking && (save_errno == EWOULDBLOCK || save_errno == EINVAL)) {
 721                 fd = robust_open(device_filename, O_RDONLY, 0);
 722                 save_errno = errno;
 723             }
 724 #else
 725             fd = robust_open(device_filename, O_RDONLY, 0);
 726             save_errno = errno;
 727 #endif
 728         }
 729     }
 730 #ifdef O_NONBLOCK
 731     /* Clear O_NONBLOCK for operations from now on. */
 732     if (fd >= 0 && nonblocking)
 733         fcntl(fd, F_SETFL, fcntl(fd, F_GETFL, 0) & ~O_NONBLOCK);
 734     errno = save_errno;
 735     /* function continues after #endif */
 736
 737 #endif /* O_NONBLOCK */
 738
 739     if (fd < 0) {
 740         DeviceStatusFlags status_flag = 0;
 741         if (errno == EBUSY)
 742             status_flag = DEVICE_STATUS_DEVICE_BUSY;
 743         else
 744             status_flag = DEVICE_STATUS_DEVICE_ERROR;
 745         device_set_error(DEVICE(self),
 746             vstrallocf(_("Can't open tape device %s: %s"), self->private->device_filename, strerror(errno)),
 747             status_flag);
 748         return -1;
 749     }
 750
 751     /* Check that this is actually a tape device. */
 752     new_status = tape_is_tape_device(fd);
 753     if (new_status & DEVICE_STATUS_DEVICE_ERROR) {
 754         device_set_error(DEVICE(self),
 755             vstrallocf(_("File %s is not a tape device"), self->private->device_filename),
 756             new_status);
 757         robust_close(fd);
 758         return -1;
 759     }
 760     if (new_status & DEVICE_STATUS_VOLUME_MISSING) {
 761         device_set_error(DEVICE(self),
 762             vstrallocf(_("Tape device %s is not ready or is empty"), self->private->device_filename),
 763             new_status);
 764         robust_close(fd);
 765         return -1;
 766     }
 767
 768     new_status = tape_is_ready(fd, self);
 769     if (new_status & DEVICE_STATUS_VOLUME_MISSING) {
 770         device_set_error(DEVICE(self),
 771             vstrallocf(_("Tape device %s is empty"), self->private->device_filename),
 772             new_status);
 773         robust_close(fd);
 774         return -1;
 775     }
 776     if (new_status != DEVICE_STATUS_SUCCESS) {
 777         device_set_error(DEVICE(self),
 778             vstrallocf(_("Tape device %s is not ready or is empty"), self->private->device_filename),
 779             new_status);
 780         robust_close(fd);
 781         return -1;
 782     }
 783
 784     return fd;
 785 }
 786
 787 static void
 788 tape_device_open_device (Device * dself, char * device_name,
 789                         char * device_type, char * device_node) {
 790     TapeDevice * self;
 791     GValue val;
 792
 793     self = TAPE_DEVICE(dself);
 794
 795     self->fd = -1;
 796     self->private->device_filename = stralloc(device_node);
 797
 798     /* Set tape drive/OS info */
 799     bzero(&val, sizeof(val));
 800     g_value_init(&val, G_TYPE_BOOLEAN);
 801
 802     self->fsf = TRUE;
 803     g_value_set_boolean(&val, self->fsf);
 804     device_set_simple_property(dself, PROPERTY_FSF, &val, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 805
 806     self->fsf_after_filemark = DEFAULT_FSF_AFTER_FILEMARK;
 807     g_value_set_boolean(&val, self->fsf_after_filemark);
 808     device_set_simple_property(dself, PROPERTY_FSF_AFTER_FILEMARK, &val, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 809
 810     self->bsf = TRUE;
 811     g_value_set_boolean(&val, self->bsf);
 812     device_set_simple_property(dself, PROPERTY_BSF, &val, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 813
 814     self->fsr = TRUE;
 815     g_value_set_boolean(&val, self->fsr);
 816     device_set_simple_property(dself, PROPERTY_FSR, &val, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 817
 818     self->bsr = TRUE;
 819     g_value_set_boolean(&val, self->bsr);
 820     device_set_simple_property(dself, PROPERTY_BSR, &val, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 821
 822     self->eom = TRUE;
 823     g_value_set_boolean(&val, self->eom);
 824     device_set_simple_property(dself, PROPERTY_EOM, &val, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 825
 826     self->leom = FALSE;
 827     g_value_set_boolean(&val, self->leom);
 828     device_set_simple_property(dself, PROPERTY_LEOM, &val, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 829
 830     self->bsf_after_eom = FALSE;
 831     g_value_set_boolean(&val, self->bsf_after_eom);
 832     device_set_simple_property(dself, PROPERTY_BSF_AFTER_EOM, &val, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 833
 834     g_value_unset(&val);
 835     g_value_init(&val, G_TYPE_UINT);
 836
 837     self->final_filemarks = 2;
 838     g_value_set_uint(&val, self->final_filemarks);
 839     device_set_simple_property(dself, PROPERTY_FINAL_FILEMARKS, &val, PROPERTY_SURETY_BAD, PROPERTY_SOURCE_DEFAULT);
 840
 841     g_value_unset(&val);
 842
 843     /* Chain up */
 844     if (parent_class->open_device) {
 845         parent_class->open_device(dself, device_name, device_type, device_node);
 846     }
 847 }
 848
 849
 850 static DeviceStatusFlags tape_device_read_label(Device * dself) {
 851     TapeDevice * self;
 852     char * header_buffer;
 853     int buffer_len;
 854     IoResult result;
 855     dumpfile_t *header;
 856     DeviceStatusFlags new_status;
 857     char *msg = NULL;
 858
 859     self = TAPE_DEVICE(dself);
 860
 861     amfree(dself->volume_label);
 862     amfree(dself->volume_time);
 863     dumpfile_free(dself->volume_header);
 864     dself->volume_header = NULL;
 865
 866     if (device_in_error(self)) return dself->status;
 867
 868     if (self->fd == -1) {
 869         self->fd = try_open_tape_device(self, self->private->device_filename);
 870         /* if the open failed, then try_open_tape_device already set the
 871          * approppriate error status */
 872         if (self->fd == -1)
 873             return dself->status;
 874     }
 875
 876     /* Rewind it. */
 877     if (!tape_rewind(self->fd)) {
 878         device_set_error(dself,
 879             vstrallocf(_("Error rewinding device %s to read label: %s"),
 880                     self->private->device_filename, strerror(errno)),
 881               DEVICE_STATUS_DEVICE_ERROR
 882             | DEVICE_STATUS_VOLUME_ERROR);
 883         return dself->status;
 884     }
 885
 886     buffer_len = tape_device_read_size(self);
 887     header_buffer = malloc(buffer_len);
 888     result = tape_device_robust_read(self, header_buffer, &buffer_len, &msg);
 889
 890     if (result != RESULT_SUCCESS) {
 891         free(header_buffer);
 892         tape_rewind(self->fd);
 893         /* I/O error. */
 894         switch (result) {
 895         case RESULT_NO_DATA:
 896             msg = stralloc(_("no data"));
 897             new_status = (DEVICE_STATUS_VOLUME_ERROR |
 898                           DEVICE_STATUS_VOLUME_UNLABELED);
 899             header = dself->volume_header = g_new(dumpfile_t, 1);
 900             fh_init(header);
 901             break;
 902
 903         case RESULT_SMALL_BUFFER:
 904             msg = stralloc(_("block size too small"));
 905             new_status = (DEVICE_STATUS_DEVICE_ERROR |
 906                           DEVICE_STATUS_VOLUME_ERROR);
 907             header = dself->volume_header = g_new(dumpfile_t, 1);
 908             fh_init(header);
 909             header->type = F_WEIRD;
 910             break;
 911
 912         default:
 913             msg = stralloc(_("unknown error"));
 914         case RESULT_ERROR:
 915             new_status = (DEVICE_STATUS_DEVICE_ERROR |
 916                           DEVICE_STATUS_VOLUME_ERROR |
 917                           DEVICE_STATUS_VOLUME_UNLABELED);
 918             break;
 919         }
 920         device_set_error(dself,
 921                  g_strdup_printf(_("Error reading Amanda header: %s"),
 922                         msg? msg : _("unknown error")),
 923                  new_status);
 924         amfree(msg);
 925         return dself->status;
 926     }
 927
 928     dself->header_block_size = buffer_len;
 929     header = dself->volume_header = g_new(dumpfile_t, 1);
 930     fh_init(header);
 931
 932     parse_file_header(header_buffer, header, buffer_len);
 933     amfree(header_buffer);
 934     if (header->type != F_TAPESTART) {
 935         device_set_error(dself,
 936                 stralloc(_("No tapestart header -- unlabeled device?")),
 937                 DEVICE_STATUS_VOLUME_UNLABELED);
 938         return dself->status;
 939     }
 940
 941     dself->volume_label = g_strdup(header->name);
 942     dself->volume_time = g_strdup(header->datestamp);
 943     /* dself->volume_header is already set */
 944
 945     device_set_error(dself, NULL, DEVICE_STATUS_SUCCESS);
 946
 947     return dself->status;
 948 }
 949
 950 static gboolean
 951 tape_device_write_block(Device * pself, guint size, gpointer data) {
 952     TapeDevice * self;
 953     char *replacement_buffer = NULL;
 954     IoResult result;
 955     char *msg = NULL;
 956
 957     self = TAPE_DEVICE(pself);
 958
 959     g_assert(self->fd >= 0);
 960     if (device_in_error(self)) return FALSE;
 961
 962     /* zero out to the end of a short block -- tape devices only write
 963      * whole blocks. */
 964     if (size < pself->block_size) {
 965         replacement_buffer = malloc(pself->block_size);
 966         memcpy(replacement_buffer, data, size);
 967         bzero(replacement_buffer+size, pself->block_size-size);
 968
 969         data = replacement_buffer;
 970         size = pself->block_size;
 971     }
 972
 973     result = tape_device_robust_write(self, data, size, &msg);
 974     amfree(replacement_buffer);
 975
 976     switch (result) {
 977         case RESULT_SUCCESS:
 978             break;
 979
 980         case RESULT_NO_SPACE:
 981             device_set_error(pself,
 982                 stralloc(_("No space left on device")),
 983                 DEVICE_STATUS_VOLUME_ERROR);
 984             pself->is_eom = TRUE;
 985             return FALSE;
 986
 987         default:
 988             msg = stralloc(_("unknown error"));
 989         case RESULT_ERROR:
 990             device_set_error(pself,
 991                 g_strdup_printf(_("Error writing block: %s"), msg),
 992                 DEVICE_STATUS_DEVICE_ERROR);
 993             amfree(msg);
 994             return FALSE;
 995     }
 996
 997     pself->block++;
 998
 999     return TRUE;
1000 }
1001
1002 static int tape_device_read_block (Device * pself, gpointer buf,
1003                                    int * size_req) {
1004     TapeDevice * self;
1005     int size;
1006     IoResult result;
1007     gssize read_block_size = tape_device_read_size(pself);
1008     char *msg = NULL;
1009
1010     self = TAPE_DEVICE(pself);
1011
1012     g_assert(self->fd >= 0);
1013     if (device_in_error(self)) return -1;
1014
1015     g_assert(read_block_size < INT_MAX); /* data type mismatch */
1016     if (buf == NULL || *size_req < (int)read_block_size) {
1017         /* Just a size query. */
1018         *size_req = (int)read_block_size;
1019         return 0;
1020     }
1021
1022     size = *size_req;
1023     result = tape_device_robust_read(self, buf, &size, &msg);
1024     switch (result) {
1025     case RESULT_SUCCESS:
1026         *size_req = size;
1027         pself->block++;
1028         return size;
1029     case RESULT_SMALL_BUFFER: {
1030         gsize new_size;
1031         GValue newval;
1032
1033         /* If this happens, it means that we have:
1034          *     (next block size) > (buffer size) >= (read_block_size)
1035          * The solution is to ask for an even bigger buffer. We also play
1036          * some games to refrain from reading above the SCSI limit or from
1037          * integer overflow.  Note that not all devices will tell us about
1038          * this problem -- some will just discard the "extra" data. */
1039         new_size = MIN(INT_MAX/2 - 1, *size_req) * 2;
1040         if (new_size > LARGEST_BLOCK_ESTIMATE &&
1041             *size_req < LARGEST_BLOCK_ESTIMATE) {
1042             new_size = LARGEST_BLOCK_ESTIMATE;
1043         }
1044         g_assert (new_size > (gsize)*size_req);
1045
1046         g_info("Device %s indicated blocksize %zd was too small; using %zd.",
1047             pself->device_name, (gsize)*size_req, new_size);
1048         *size_req = (int)new_size;
1049         self->private->read_block_size = new_size;
1050
1051         bzero(&newval, sizeof(newval));
1052         g_value_init(&newval, G_TYPE_UINT);
1053         g_value_set_uint(&newval, self->private->read_block_size);
1054         device_set_simple_property(pself, PROPERTY_READ_BLOCK_SIZE,
1055                 &newval, PROPERTY_SURETY_GOOD, PROPERTY_SOURCE_DETECTED);
1056         g_value_unset(&newval);
1057
1058         return 0;
1059     }
1060     case RESULT_NO_DATA:
1061         pself->is_eof = TRUE;
1062         pself->in_file = FALSE;
1063         device_set_error(pself,
1064             stralloc(_("EOF")),
1065             DEVICE_STATUS_SUCCESS);
1066         return -1;
1067
1068     default:
1069         msg = stralloc(_("unknown error"));
1070     case RESULT_ERROR:
1071         device_set_error(pself,
1072             vstrallocf(_("Error reading from tape device: %s"), msg),
1073             DEVICE_STATUS_VOLUME_ERROR | DEVICE_STATUS_DEVICE_ERROR);
1074         amfree(msg);
1075         return -1;
1076     }
1077
1078     g_assert_not_reached();
1079 }
1080
1081 /* Just a helper function for tape_device_start(). */
1082 static gboolean write_tapestart_header(TapeDevice * self, char * label,
1083                                        char * timestamp) {
1084      IoResult result;
1085      dumpfile_t * header;
1086      char * header_buf;
1087      Device * d_self = (Device*)self;
1088      char *msg = NULL;
1089
1090      tape_rewind(self->fd);
1091
1092      header = make_tapestart_header(d_self, label, timestamp);
1093      g_assert(header != NULL);
1094      header_buf = device_build_amanda_header(d_self, header, NULL);
1095      if (header_buf == NULL) {
1096          device_set_error(d_self,
1097             stralloc(_("Tapestart header won't fit in a single block!")),
1098             DEVICE_STATUS_DEVICE_ERROR);
1099          dumpfile_free(header);
1100          return FALSE;
1101      }
1102      dumpfile_free(d_self->volume_header);
1103      d_self->volume_header = NULL;
1104
1105      result = tape_device_robust_write(self, header_buf, d_self->block_size, &msg);
1106      if (result != RESULT_SUCCESS) {
1107         device_set_error(d_self,
1108             g_strdup_printf(_("Error writing tapestart header: %s"),
1109                         (result == RESULT_ERROR)? msg : _("out of space")),
1110             DEVICE_STATUS_DEVICE_ERROR);
1111
1112         if (result == RESULT_NO_SPACE)
1113             d_self->is_eom = TRUE;
1114
1115         amfree(msg);
1116         dumpfile_free(header);
1117         amfree(header_buf);
1118         return FALSE;
1119      }
1120
1121      d_self->header_block_size = d_self->block_size;
1122      amfree(header_buf);
1123
1124      if (!tape_weof(self->fd, 1)) {
1125         device_set_error(d_self,
1126                          vstrallocf(_("Error writing filemark: %s"),
1127                                     strerror(errno)),
1128                          DEVICE_STATUS_DEVICE_ERROR|DEVICE_STATUS_VOLUME_ERROR);
1129         /* can't tell if this was EOM or not, so assume it is */
1130         d_self->is_eom = TRUE;
1131         dumpfile_free(header);
1132         return FALSE;
1133      }
1134
1135      d_self->volume_header = header;
1136      return TRUE;
1137 }
1138
1139 static gboolean
1140 tape_device_start (Device * d_self, DeviceAccessMode mode, char * label,
1141                    char * timestamp) {
1142     TapeDevice * self;
1143
1144     self = TAPE_DEVICE(d_self);
1145
1146     if (device_in_error(self)) return FALSE;
1147
1148     if (self->fd == -1) {
1149         self->fd = try_open_tape_device(self, self->private->device_filename);
1150         /* if the open failed, then try_open_tape_device already set the
1151          * approppriate error status */
1152         if (self->fd == -1)
1153             return FALSE;
1154     }
1155
1156     if (mode != ACCESS_WRITE && d_self->volume_label == NULL) {
1157         /* we need a labeled volume for APPEND and READ */
1158         if (tape_device_read_label(d_self) != DEVICE_STATUS_SUCCESS)
1159             return FALSE;
1160     }
1161
1162     d_self->access_mode = mode;
1163     d_self->in_file = FALSE;
1164
1165     if (IS_WRITABLE_ACCESS_MODE(mode)) {
1166         if (self->write_open_errno != 0) {
1167             /* We tried and failed to open the device in write mode. */
1168             device_set_error(d_self,
1169                 vstrallocf(_("Can't open tape device %s for writing: %s"),
1170                             self->private->device_filename, strerror(self->write_open_errno)),
1171                 DEVICE_STATUS_DEVICE_ERROR | DEVICE_STATUS_VOLUME_ERROR);
1172             return FALSE;
1173         } else if (!tape_rewind(self->fd)) {
1174             device_set_error(d_self,
1175                 vstrallocf(_("Error rewinding device to start: %s"), strerror(errno)),
1176                 DEVICE_STATUS_DEVICE_ERROR);
1177             return FALSE;
1178         }
1179     }
1180
1181     /* Position the tape */
1182     switch (mode) {
1183     case ACCESS_APPEND:
1184         if (d_self->volume_label == NULL && device_read_label(d_self) != DEVICE_STATUS_SUCCESS) {
1185             /* device_read_label already set our error message */
1186             return FALSE;
1187         }
1188
1189         if (!tape_device_eod(self)) {
1190             device_set_error(d_self,
1191                 vstrallocf(_("Couldn't seek to end of tape: %s"), strerror(errno)),
1192                 DEVICE_STATUS_DEVICE_ERROR);
1193             return FALSE;
1194         }
1195         break;
1196
1197     case ACCESS_READ:
1198         if (d_self->volume_label == NULL && device_read_label(d_self) != DEVICE_STATUS_SUCCESS) {
1199             /* device_read_label already set our error message */
1200             return FALSE;
1201         }
1202
1203         if (!tape_rewind(self->fd)) {
1204             device_set_error(d_self,
1205                 vstrallocf(_("Error rewinding device after reading label: %s"), strerror(errno)),
1206                 DEVICE_STATUS_DEVICE_ERROR);
1207             return FALSE;
1208         }
1209         d_self->file = 0;
1210         break;
1211
1212     case ACCESS_WRITE:
1213         if (!write_tapestart_header(self, label, timestamp)) {
1214             /* write_tapestart_header already set the error status */
1215             return FALSE;
1216         }
1217
1218         d_self->volume_label = newstralloc(d_self->volume_label, label);
1219         d_self->volume_time = newstralloc(d_self->volume_time, timestamp);
1220
1221         /* unset the VOLUME_UNLABELED flag, if it was set */
1222         device_set_error(d_self, NULL, DEVICE_STATUS_SUCCESS);
1223         d_self->file = 0;
1224         break;
1225
1226     default:
1227         g_assert_not_reached();
1228     }
1229
1230     return TRUE;
1231 }
1232
1233 static gboolean tape_device_start_file(Device * d_self,
1234                                        dumpfile_t * info) {
1235     TapeDevice * self;
1236     IoResult result;
1237     char * amanda_header;
1238     char *msg = NULL;
1239
1240     self = TAPE_DEVICE(d_self);
1241
1242     g_assert(self->fd >= 0);
1243     if (device_in_error(self)) return FALSE;
1244
1245     /* set the blocksize in the header properly */
1246     info->blocksize = d_self->block_size;
1247
1248     /* Make the Amanda header suitable for writing to the device. */
1249     /* Then write the damn thing. */
1250     amanda_header = device_build_amanda_header(d_self, info, NULL);
1251     if (amanda_header == NULL) {
1252         device_set_error(d_self,
1253             stralloc(_("Amanda file header won't fit in a single block!")),
1254             DEVICE_STATUS_DEVICE_ERROR);
1255         return FALSE;
1256     }
1257
1258     result = tape_device_robust_write(self, amanda_header, d_self->block_size, &msg);
1259     if (result != RESULT_SUCCESS) {
1260         device_set_error(d_self,
1261             vstrallocf(_("Error writing file header: %s"),
1262                         (result == RESULT_ERROR)? msg : _("out of space")),
1263             DEVICE_STATUS_DEVICE_ERROR);
1264
1265         if (result == RESULT_NO_SPACE)
1266             d_self->is_eom = TRUE;
1267
1268         amfree(amanda_header);
1269         amfree(msg);
1270         return FALSE;
1271     }
1272     amfree(amanda_header);
1273
1274     /* arrange the file numbers correctly */
1275     d_self->in_file = TRUE;
1276     d_self->block = 0;
1277     if (d_self->file >= 0)
1278         d_self->file ++;
1279     return TRUE;
1280 }
1281
1282 static gboolean
1283 tape_device_finish_file (Device * d_self) {
1284     TapeDevice * self;
1285
1286     self = TAPE_DEVICE(d_self);
1287     if (device_in_error(d_self)) return FALSE;
1288
1289     if (!tape_weof(self->fd, 1)) {
1290         device_set_error(d_self,
1291                 vstrallocf(_("Error writing filemark: %s"), strerror(errno)),
1292                 DEVICE_STATUS_DEVICE_ERROR | DEVICE_STATUS_VOLUME_ERROR);
1293         /* can't tell if this was EOM or not, so assume it is */
1294         d_self->is_eom = TRUE;
1295         return FALSE;
1296     }
1297
1298     d_self->in_file = FALSE;
1299     return TRUE;
1300 }
1301
1302 static dumpfile_t *
1303 tape_device_seek_file (Device * d_self, guint file) {
1304     TapeDevice * self;
1305     gint got_file;
1306     int difference;
1307     char * header_buffer;
1308     dumpfile_t * rval;
1309     int buffer_len;
1310     IoResult result;
1311     char *msg;
1312
1313     self = TAPE_DEVICE(d_self);
1314
1315     if (device_in_error(self)) return NULL;
1316
1317     difference = file - d_self->file;
1318
1319     /* Check if we already read a filemark. */
1320     /* If we already read a filemark and the drive automaticaly goes to the
1321        next file, then we must reduce the difference by one. */
1322     if (d_self->is_eof && !self->fsf_after_filemark) {
1323         difference --;
1324     }
1325
1326     d_self->in_file = FALSE;
1327     d_self->is_eof = FALSE;
1328     d_self->block = 0;
1329
1330 reseek:
1331     if (difference > 0) {
1332         /* Seeking forwards */
1333         if (!tape_device_fsf(self, difference)) {
1334             tape_rewind(self->fd);
1335             device_set_error(d_self,
1336                 vstrallocf(_("Could not seek forward to file %d"), file),
1337                 DEVICE_STATUS_VOLUME_ERROR | DEVICE_STATUS_DEVICE_ERROR);
1338             return NULL;
1339         }
1340     } else { /* (difference <= 0) */
1341         /* Seeking backwards, or to this file itself */
1342
1343         /* if the drive supports bsf, we can do this the fancy way */
1344         if (self->bsf) {
1345             /* bsf one more than the difference */
1346             if (!tape_bsf(self->fd, -difference + 1)) {
1347                 tape_rewind(self->fd);
1348                 device_set_error(d_self,
1349                     vstrallocf(_("Could not seek backward to file %d"), file),
1350                     DEVICE_STATUS_VOLUME_ERROR | DEVICE_STATUS_DEVICE_ERROR);
1351                 return NULL;
1352             }
1353
1354             /* now we are on the BOT side of the desired filemark, so FSF to get to the
1355              * EOT side of it */
1356             if (!tape_device_fsf(self, 1)) {
1357                 tape_rewind(self->fd);
1358                 device_set_error(d_self,
1359                     vstrallocf(_("Could not seek forward to file %d"), file),
1360                     DEVICE_STATUS_VOLUME_ERROR | DEVICE_STATUS_DEVICE_ERROR);
1361                 return NULL;
1362             }
1363         } else {
1364             /* no BSF, so just rewind and seek forward */
1365             if (!tape_rewind(self->fd)) {
1366                 device_set_error(d_self,
1367                     vstrallocf(_("Could not rewind device while emulating BSF")),
1368                     DEVICE_STATUS_VOLUME_ERROR | DEVICE_STATUS_DEVICE_ERROR);
1369                 return FALSE;
1370             }
1371
1372             if (!tape_device_fsf(self, file)) {
1373                 tape_rewind(self->fd);
1374                 device_set_error(d_self,
1375                     vstrallocf(_("Could not seek forward to file %d"), file),
1376                     DEVICE_STATUS_VOLUME_ERROR | DEVICE_STATUS_DEVICE_ERROR);
1377                 return NULL;
1378             }
1379         }
1380     }
1381
1382     /* double-check that we're on the right fileno, if possible.  This is most
1383      * likely a programming error if it occurs, but could also be due to a weird
1384      * tape drive or driver (and that would *never* happen, right?) */
1385     got_file = tape_fileno(self->fd);
1386     if (got_file >= 0 && (guint)got_file != file) {
1387         device_set_error(d_self,
1388                 vstrallocf(_("Could not seek to file %d correctly; got %d"),
1389                             file, got_file),
1390                 DEVICE_STATUS_DEVICE_ERROR);
1391         d_self->file = (guint)got_file;
1392         return NULL;
1393     }
1394
1395     buffer_len = tape_device_read_size(d_self);
1396     header_buffer = malloc(buffer_len);
1397     d_self->is_eof = FALSE;
1398     result = tape_device_robust_read(self, header_buffer, &buffer_len, &msg);
1399
1400     if (result != RESULT_SUCCESS) {
1401         free(header_buffer);
1402         tape_rewind(self->fd);
1403         switch (result) {
1404         case RESULT_NO_DATA:
1405             /* If we read 0 bytes, that means we encountered a double
1406              * filemark, which indicates end of tape. This should
1407              * work even with QIC tapes on operating systems with
1408              * proper support. */
1409             d_self->file = file; /* other attributes are already correct */
1410             return make_tapeend_header();
1411
1412         case RESULT_SMALL_BUFFER:
1413             msg = stralloc(_("block size too small"));
1414             break;
1415
1416         default:
1417             msg = stralloc(_("unknown error"));
1418         case RESULT_ERROR:
1419             break;
1420         }
1421         device_set_error(d_self,
1422             g_strdup_printf(_("Error reading Amanda header: %s"), msg),
1423             DEVICE_STATUS_DEVICE_ERROR | DEVICE_STATUS_VOLUME_ERROR);
1424         amfree(msg);
1425         return NULL;
1426     }
1427
1428     rval = g_new(dumpfile_t, 1);
1429     parse_file_header(header_buffer, rval, buffer_len);
1430     amfree(header_buffer);
1431     switch (rval->type) {
1432     case F_DUMPFILE:
1433     case F_CONT_DUMPFILE:
1434     case F_SPLIT_DUMPFILE:
1435         break;
1436
1437     case F_NOOP:
1438         /* a NOOP is written on QIC tapes to avoid writing two sequential
1439          * filemarks when closing a device in WRITE or APPEND mode.  In this
1440          * case, we just seek to the next file. */
1441         amfree(rval);
1442         file++;
1443         difference = 1;
1444         goto reseek;
1445
1446     default:
1447         tape_rewind(self->fd);
1448         device_set_error(d_self,
1449             stralloc(_("Invalid amanda header while reading file header")),
1450             DEVICE_STATUS_VOLUME_ERROR);
1451         amfree(rval);
1452         return NULL;
1453     }
1454
1455     d_self->in_file = TRUE;
1456     d_self->file = file;
1457
1458     return rval;
1459 }
1460
1461 static gboolean
1462 tape_device_seek_block (Device * d_self, guint64 block) {
1463     TapeDevice * self;
1464     int difference;
1465
1466     self = TAPE_DEVICE(d_self);
1467
1468     if (device_in_error(self)) return FALSE;
1469
1470     difference = block - d_self->block;
1471
1472     if (difference > 0) {
1473         if (!tape_device_fsr(self, difference)) {
1474             device_set_error(d_self,
1475                 vstrallocf(_("Could not seek forward to block %ju: %s"), (uintmax_t)block, strerror(errno)),
1476                 DEVICE_STATUS_VOLUME_ERROR | DEVICE_STATUS_DEVICE_ERROR);
1477             return FALSE;
1478         }
1479     } else if (difference < 0) {
1480         if (!tape_device_bsr(self, difference, d_self->file, d_self->block)) {
1481             device_set_error(d_self,
1482                 vstrallocf(_("Could not seek backward to block %ju: %s"), (uintmax_t)block, strerror(errno)),
1483                 DEVICE_STATUS_VOLUME_ERROR | DEVICE_STATUS_DEVICE_ERROR);
1484             return FALSE;
1485         }
1486     }
1487
1488     d_self->block = block;
1489     return TRUE;
1490 }
1491
1492 static gboolean
1493 tape_device_eject (Device * d_self) {
1494     TapeDevice * self;
1495
1496     self = TAPE_DEVICE(d_self);
1497
1498     if (device_in_error(self)) return FALSE;
1499
1500     /* Open the device if not already opened */
1501     if (self->fd == -1) {
1502         self->fd = try_open_tape_device(self, self->private->device_filename);
1503         /* if the open failed, then try_open_tape_device already set the
1504          * approppriate error status */
1505         if (self->fd == -1)
1506             return FALSE;
1507     }
1508
1509     /* Rewind it. */
1510     if (!tape_rewind(self->fd)) {
1511         device_set_error(d_self,
1512             vstrallocf(_("Error rewinding device %s before ejecting: %s"),
1513                        self->private->device_filename, strerror(errno)),
1514               DEVICE_STATUS_DEVICE_ERROR
1515             | DEVICE_STATUS_VOLUME_ERROR);
1516         return FALSE;
1517     }
1518
1519     if (tape_offl(self->fd))
1520         return TRUE;
1521
1522     device_set_error(d_self,
1523         vstrallocf(_("Error ejecting device %s: %s\n"),
1524                    self->private->device_filename, strerror(errno)),
1525           DEVICE_STATUS_DEVICE_ERROR);
1526
1527     return FALSE;
1528 }
1529
1530 static gboolean
1531 tape_device_finish (Device * d_self) {
1532     TapeDevice * self;
1533     char *msg = NULL;
1534
1535     self = TAPE_DEVICE(d_self);
1536
1537     if (device_in_error(self))
1538         goto finish_error;
1539
1540     /* if we're already in ACCESS_NULL, then there are no filemarks or anything
1541      * to worry about, but we need to release the kernel device */
1542     if (d_self->access_mode == ACCESS_NULL) {
1543         robust_close(self->fd);
1544         self->fd = -1;
1545         return TRUE;
1546     }
1547
1548     /* Polish off this file, if relevant. */
1549     if (d_self->in_file && IS_WRITABLE_ACCESS_MODE(d_self->access_mode)) {
1550         if (!device_finish_file(d_self))
1551             goto finish_error;
1552     }
1553
1554     /* Straighten out the filemarks.  We already wrote one in finish_file, and
1555      * the device driver will write another filemark when we rewind.  This means
1556      * that, if we do nothing, we'll get two filemarks.  If final_filemarks is
1557      * 1, this would be wrong, so in this case we insert a F_NOOP header between
1558      * the two filemarks. */
1559     if (self->final_filemarks == 1 &&
1560         IS_WRITABLE_ACCESS_MODE(d_self->access_mode)) {
1561         dumpfile_t file;
1562         char *header;
1563         int result;
1564
1565         /* write a F_NOOP header */
1566         fh_init(&file);
1567         file.type = F_NOOP;
1568         header = device_build_amanda_header(d_self, &file, NULL);
1569         if (!header) {
1570             device_set_error(d_self,
1571                 stralloc(_("Amanda file header won't fit in a single block!")),
1572                 DEVICE_STATUS_DEVICE_ERROR);
1573             goto finish_error;
1574         }
1575
1576         result = tape_device_robust_write(self, header, d_self->block_size, &msg);
1577         if (result != RESULT_SUCCESS) {
1578             device_set_error(d_self,
1579                 vstrallocf(_("Error writing file header: %s"),
1580                             (result == RESULT_ERROR)? msg : _("out of space")),
1581                 DEVICE_STATUS_DEVICE_ERROR);
1582             amfree(header);
1583             amfree(msg);
1584             goto finish_error;
1585         }
1586         amfree(header);
1587     }
1588
1589     /* Rewind (the kernel will write a filemark first) */
1590     if (!tape_rewind(self->fd)) {
1591         device_set_error(d_self,
1592             vstrallocf(_("Couldn't rewind device to finish: %s"), strerror(errno)),
1593             DEVICE_STATUS_DEVICE_ERROR);
1594         goto finish_error;
1595     }
1596
1597     d_self->is_eof = FALSE;
1598     d_self->access_mode = ACCESS_NULL;
1599
1600     /* release the kernel's device */
1601     robust_close(self->fd);
1602     self->fd = -1;
1603
1604     return TRUE;
1605
1606 finish_error:
1607     d_self->access_mode = ACCESS_NULL;
1608
1609     /* release the kernel's device */
1610     robust_close(self->fd);
1611     self->fd = -1;
1612
1613     return FALSE;
1614 }
1615
1616 /* Works just like read(), except for the following:
1617  * 1) Retries on EINTR & friends.
1618  * 2) Stores count in parameter, not return value.
1619  * 3) Provides explicit return result.
1620  * *errmsg is only set on RESULT_ERROR.
1621  */
1622 static IoResult
1623 tape_device_robust_read (TapeDevice * self, void * buf, int * count, char **errmsg) {
1624     Device * d_self;
1625     int result;
1626
1627     d_self = (Device*)self;
1628
1629     /* Callers should ensure this. */
1630     g_assert(*count >= 0);
1631
1632     for (;;) {
1633         result = read(self->fd, buf, *count);
1634         if (result > 0) {
1635             /* Success. By definition, we read a full block. */
1636             d_self->is_eof = FALSE;
1637             *count = result;
1638             return RESULT_SUCCESS;
1639         } else if (result == 0) {
1640             d_self->is_eof = TRUE;
1641             return RESULT_NO_DATA;
1642         } else {
1643             if (0
1644 #ifdef EAGAIN
1645                 || errno == EAGAIN
1646 #endif
1647 #ifdef EWOULDBLOCK
1648                 || errno == EWOULDBLOCK
1649 #endif
1650 #ifdef EINTR
1651                 || errno == EINTR
1652 #endif
1653                 ) {
1654                 /* Interrupted system call */
1655                 continue;
1656             } else if ((0
1657 #ifdef ENOMEM
1658                         || errno == ENOMEM /* bad user-space buffer */
1659 #endif
1660 #ifdef EOVERFLOW
1661                         || errno == EOVERFLOW /* bad kernel-space buffer */
1662 #endif
1663 #ifdef EINVAL
1664                         || errno == EINVAL /* ??? */
1665 #endif
1666                         )) {
1667                 /* Buffer too small. */
1668                 g_warning("Buffer is too small (%d bytes) from %s: %s",
1669                         *count, self->private->device_filename, strerror(errno));
1670                 return RESULT_SMALL_BUFFER;
1671             } else {
1672                 *errmsg = g_strdup_printf(_("Error reading %d bytes from %s: %s"),
1673                         *count, self->private->device_filename, strerror(errno));
1674                 return RESULT_ERROR;
1675             }
1676         }
1677     }
1678
1679     g_assert_not_reached();
1680 }
1681
1682 /* Kernel workaround: If needed, poke the kernel so it doesn't fail.
1683    at the 2GB boundry. Parameters are G_GNUC_UNUSED in case NEED_RESETOFS
1684    is not defined. */
1685 static void check_resetofs(TapeDevice * self G_GNUC_UNUSED,
1686                            int count G_GNUC_UNUSED) {
1687 #ifdef NEED_RESETOFS
1688     Device * d_self;
1689     int result;
1690
1691     d_self = (Device*)self;
1692
1693     self->private->write_count += count;
1694     if (self->private->write_count < RESETOFS_THRESHOLD) {
1695         return;
1696     }
1697
1698     result = lseek(self->fd, 0, SEEK_SET);
1699     if (result < 0) {
1700         g_warning(_("lseek() failed during kernel 2GB workaround: %s"),
1701                strerror(errno));
1702     }
1703 #endif
1704 }
1705
1706 /* *errmsg is only set on RESULT_ERROR */
1707 static IoResult
1708 tape_device_robust_write (TapeDevice * self, void * buf, int count, char **errmsg) {
1709     Device * d_self;
1710     int result;
1711     gboolean retry = FALSE;
1712
1713     d_self = (Device*)self;
1714
1715     check_resetofs(self, count);
1716
1717     for (;;) {
1718         result = write(self->fd, buf, count);
1719
1720         /* Success. */
1721         if (result == count)
1722             return RESULT_SUCCESS;
1723
1724         if (result > 0) {
1725             /* write() returned a short count. This should not happen if the block sizes
1726              * are properly aligned. */
1727             *errmsg = g_strdup_printf("Short write on tape device: Tried %d, got %d.  Is "
1728                             "the drive using a block size smaller than %d bytes?",
1729                                 count, result, count);
1730             return RESULT_ERROR;
1731         }
1732
1733         /* Detect LEOM (early warning) and handle properly
1734          *
1735          * FreeBSD: 0-length write; next write will succeed
1736          *   http://lists.freebsd.org/pipermail/freebsd-scsi/2010-June/004414.html
1737          *
1738          * Solaris: 0-length write; next write will succeed
1739          *   (from Matthew Jacob on FreeBSD thread)
1740          *
1741          * Linux: -1/ENOSPC; next write will succeed
1742          *   http://www.mjmwired.net/kernel/Documentation/scsi/st.txt
1743          *
1744          * HP/UX: -1/ENOSPC; next write will succeed
1745          *   http://www.adssasia.com/Manual/IBM%203581%20tape%20autoloader.pdf
1746          */
1747         if (result == 0
1748 #ifdef ENOSPC
1749                         || (result < 0 && errno == ENOSPC)
1750 #endif
1751         ) {
1752             /* if we've retried once already, then we're probably really out of space */
1753             if (retry)
1754                 return RESULT_NO_SPACE;
1755             retry = TRUE;
1756             d_self->is_eom = TRUE;
1757
1758             g_debug("empty write to tape; treating as LEOM early warning and retrying");
1759             continue;
1760         }
1761
1762         /* at this point result < 0, so an error occurred - sort out what */
1763
1764         if (0
1765 #ifdef EAGAIN
1766                    || errno == EAGAIN
1767 #endif
1768 #ifdef EWOULDBLOCK
1769                    || errno == EWOULDBLOCK
1770 #endif
1771 #ifdef EINTR
1772                    || errno == EINTR
1773 #endif
1774                    ) {
1775                 /* Interrupted system call */
1776             continue;
1777         } else if (0
1778 #ifdef ENOSPC
1779                    || errno == ENOSPC
1780 #endif
1781 #ifdef EIO
1782                    || errno == EIO
1783 #endif
1784                    ) {
1785             /* Probably EOT. Print a message if we got EIO. */
1786 #ifdef EIO
1787             if (errno == EIO) {
1788                 g_warning(_("Got EIO on %s, assuming end of tape"),
1789                         self->private->device_filename);
1790             }
1791 #endif
1792             return RESULT_NO_SPACE;
1793         } else {
1794             /* WTF */
1795             *errmsg = vstrallocf(_("Kernel gave unexpected write() result of \"%s\" on device %s"),
1796                             strerror(errno), self->private->device_filename);
1797             return RESULT_ERROR;
1798         }
1799     }
1800
1801     g_assert_not_reached();
1802 }
1803
1804 /* Reads some number of tape blocks into the bit-bucket. If the count
1805    is negative, then we read the rest of the entire file. Returns the
1806    number of blocks read, or -1 if an error occured. If we encounter
1807    EOF (as opposed to some other error) we return the number of blocks
1808    actually read. */
1809 static int drain_tape_blocks(TapeDevice * self, int count) {
1810     char * buffer;
1811     gsize buffer_size;
1812     int i;
1813
1814     buffer_size = tape_device_read_size(self);
1815
1816     buffer = malloc(buffer_size);
1817
1818     for (i = 0; i < count || count < 0;) {
1819         int result;
1820
1821         result = read(self->fd, buffer, buffer_size);
1822         if (result > 0) {
1823             i ++;
1824             continue;
1825         } else if (result == 0) {
1826             amfree(buffer);
1827             return i;
1828         } else {
1829             /* First check for interrupted system call. */
1830             if (0
1831 #ifdef EAGAIN
1832                 || errno == EAGAIN
1833 #endif
1834 #ifdef EWOULDBLOCK
1835                 || errno == EWOULDBLOCK
1836 #endif
1837 #ifdef EINTR
1838                 || errno == EINTR
1839 #endif
1840                 ) {
1841                 /* Interrupted system call */
1842                 continue;
1843             } else if (0
1844 #ifdef ENOSPC
1845                        || errno == ENOSPC /* bad user-space buffer */
1846 #endif
1847 #ifdef EOVERFLOW
1848                        || errno == EOVERFLOW /* bad kernel-space buffer */
1849 #endif
1850 #ifdef EINVAL
1851                        || errno == EINVAL /* ??? */
1852 #endif
1853                        ) {
1854                 /* The buffer may not be big enough. But the OS is not
1855                    100% clear. We double the buffer and try again, but
1856                    in no case allow a buffer bigger than 32 MB. */
1857                 buffer_size *= 2;
1858
1859                 if (buffer_size > 32*1024*1024) {
1860                     amfree(buffer);
1861                     return -1;
1862                 } else {
1863                     buffer = realloc(buffer, buffer_size);
1864                     continue;
1865                 }
1866             }
1867         }
1868     }
1869
1870     amfree(buffer);
1871     return count;
1872 }
1873
1874 static gboolean
1875 tape_device_fsf (TapeDevice * self, guint count) {
1876     if (self->fsf) {
1877         return tape_fsf(self->fd, count);
1878     } else {
1879         guint i;
1880         for (i = 0; i < count; i ++) {
1881             if (drain_tape_blocks(self, -1) < 0)
1882                 return FALSE;
1883         }
1884         return TRUE;
1885     }
1886 }
1887
1888
1889 static gboolean
1890 tape_device_fsr (TapeDevice * self, guint count) {
1891     if (self->fsr) {
1892         return tape_fsr(self->fd, count);
1893     } else {
1894         int result = drain_tape_blocks(self, count);
1895         return result > 0 && (int)count == result;
1896     }
1897 }
1898
1899 /* Seek back the given number of blocks to block number block within
1900  * the current file, numbered file. */
1901
1902 static gboolean
1903 tape_device_bsr (TapeDevice * self, guint count, guint file, guint block) {
1904     if (self->bsr) {
1905         return tape_bsr(self->fd, count);
1906     } else if (self->bsf && self->fsf) {
1907         /* BSF, FSF to the right side of the filemark, and then FSR. */
1908         if (!tape_bsf(self->fd, 1))
1909             return FALSE;
1910
1911         if (!tape_fsf(self->fd, 1))
1912             return FALSE;
1913
1914         return tape_device_fsr(self, block);
1915     } else {
1916         /* rewind, FSF, and FSR */
1917         if (!tape_rewind(self->fd))
1918             return FALSE;
1919
1920         if (!tape_device_fsf(self, file))
1921             return FALSE;
1922
1923         return tape_device_fsr(self, block);
1924     }
1925     g_assert_not_reached();
1926 }
1927
1928 /* Go to the right place to write more data, and update the file
1929    number if possible. */
1930 static gboolean
1931 tape_device_eod (TapeDevice * self) {
1932     Device * d_self;
1933     int count;
1934
1935     d_self = (Device*)self;
1936
1937     if (self->eom) {
1938         int result;
1939         result = tape_eod(self->fd);
1940         if (result == TAPE_OP_ERROR) {
1941             return FALSE;
1942         } else if (result != TAPE_POSITION_UNKNOWN) {
1943             /* great - we just fast-forwarded to EOD, but don't know where we are, so
1944              * now we have to rewind and drain all of that data.  Warn the user so that
1945              * we can skip the fast-forward-rewind stage on the next run */
1946             g_warning("Seek to end of tape does not give an accurate tape position; set "
1947                       "the EOM property to 0 to avoid useless tape movement.");
1948             /* and set the property so that next time *this* object is opened for
1949              * append, we skip this stage */
1950             self->eom = FALSE;
1951             /* fall through to draining blocks, below */
1952         } else {
1953             /* We drop by 1 because Device will increment the first
1954                time the user does start_file. */
1955             d_self->file = result - 1;
1956             return TRUE;
1957         }
1958     }
1959
1960     if (!tape_rewind(self->fd))
1961         return FALSE;
1962
1963     count = 0;
1964     for (;;) {
1965         /* We alternately read a block and FSF. If the read is
1966            successful, then we are not there yet and should FSF
1967            again. */
1968         int result;
1969         result = drain_tape_blocks(self, 1);
1970         if (result == 1) {
1971             /* More data, FSF. */
1972             tape_device_fsf(self, 1);
1973             count ++;
1974         } else if (result == 0) {
1975             /* Finished. */
1976             d_self->file = count - 1;
1977             return TRUE;
1978         } else {
1979             return FALSE;
1980         }
1981     }
1982 }
1983
1984 static Device *
1985 tape_device_factory (char * device_name, char * device_type, char * device_node) {
1986     Device * rval;
1987     g_assert(0 == strcmp(device_type, "tape"));
1988     rval = DEVICE(g_object_new(TYPE_TAPE_DEVICE, NULL));
1989     device_open_device(rval, device_name, device_type, device_node);
1990     return rval;
1991 }
1992
1993 /*
1994  * Tape Operations using the POSIX interface
1995  */
1996
1997 /* Having one name for every operation would be too easy. */
1998 #if !defined(MTCOMPRESSION) && defined(MTCOMP)
1999 # define MTCOMPRESSION MTCOMP
2000 #endif
2001
2002 #if !defined(MTSETBLK) && defined(MTSETBSIZ)
2003 # define MTSETBLK MTSETBSIZ
2004 #endif
2005
2006 #if !defined(MTEOM) && defined(MTEOD)
2007 # define MTEOM MTEOD
2008 #endif
2009
2010 gboolean tape_rewind(int fd) {
2011     int count = 5;
2012     time_t stop_time;
2013
2014     /* We will retry this for up to 30 seconds or 5 retries,
2015        whichever is less, because some hardware/software combinations
2016        (notably EXB-8200 on FreeBSD) can fail to rewind. */
2017     stop_time = time(NULL) + 30;
2018
2019     while (--count >= 0 && time(NULL) < stop_time) {
2020         struct mtop mt;
2021         mt.mt_op = MTREW;
2022         mt.mt_count = 1;
2023
2024         if (0 == ioctl(fd, MTIOCTOP, &mt))
2025             return TRUE;
2026
2027         sleep(3);
2028     }
2029
2030     return FALSE;
2031 }
2032
2033 gboolean tape_fsf(int fd, guint count) {
2034     struct mtop mt;
2035     mt.mt_op = MTFSF;
2036     mt.mt_count = count;
2037     return 0 == ioctl(fd, MTIOCTOP, &mt);
2038 }
2039
2040 gboolean tape_bsf(int fd, guint count) {
2041     struct mtop mt;
2042     mt.mt_op = MTBSF;
2043     mt.mt_count = count;
2044     return 0 == ioctl(fd, MTIOCTOP, &mt);
2045 }
2046
2047 gboolean tape_fsr(int fd, guint count) {
2048     struct mtop mt;
2049     mt.mt_op = MTFSR;
2050     mt.mt_count = count;
2051     return 0 == ioctl(fd, MTIOCTOP, &mt);
2052 }
2053
2054 gboolean tape_bsr(int fd, guint count) {
2055     struct mtop mt;
2056     mt.mt_op = MTBSR;
2057     mt.mt_count = count;
2058     return 0 == ioctl(fd, MTIOCTOP, &mt);
2059 }
2060
2061 gint tape_fileno(int fd) {
2062     struct mtget get;
2063
2064     if (0 != ioctl(fd, MTIOCGET, &get))
2065         return TAPE_POSITION_UNKNOWN;
2066     if (get.mt_fileno < 0)
2067         return TAPE_POSITION_UNKNOWN;
2068     else
2069         return get.mt_fileno;
2070 }
2071
2072 gint tape_eod(int fd) {
2073     struct mtop mt;
2074     struct mtget get;
2075     mt.mt_op = MTEOM;
2076     mt.mt_count = 1;
2077     if (0 != ioctl(fd, MTIOCTOP, &mt))
2078         return TAPE_OP_ERROR;
2079
2080     /* Ignored result. This is just to flush buffers. */
2081     mt.mt_op = MTNOP;
2082     ioctl(fd, MTIOCTOP, &mt);
2083
2084     if (0 != ioctl(fd, MTIOCGET, &get))
2085         return TAPE_POSITION_UNKNOWN;
2086     if (get.mt_fileno < 0)
2087         return TAPE_POSITION_UNKNOWN;
2088     else
2089         return get.mt_fileno;
2090 }
2091
2092 gboolean tape_weof(int fd, guint8 count) {
2093     struct mtop mt;
2094     mt.mt_op = MTWEOF;
2095     mt.mt_count = count;
2096     return 0 == ioctl(fd, MTIOCTOP, &mt);
2097 }
2098
2099 gboolean tape_setcompression(int fd G_GNUC_UNUSED,
2100         gboolean on G_GNUC_UNUSED) {
2101 #ifdef MTCOMPRESSION
2102     struct mtop mt;
2103     mt.mt_op = MTCOMPRESSION;
2104     mt.mt_count = on;
2105     return 0 == ioctl(fd, MTIOCTOP, &mt);
2106 #else
2107     return 0;
2108 #endif
2109 }
2110
2111 gboolean tape_offl(int fd) {
2112     struct mtop mt;
2113     int safe_errno;
2114
2115     mt.mt_op = MTOFFL;
2116     mt.mt_count = 1;
2117     if (0 == ioctl(fd, MTIOCTOP, &mt))
2118         return TRUE;
2119
2120     safe_errno = errno;
2121     g_debug("tape_off: ioctl(MTIOCTOP/MTOFFL) failed: %s", strerror(errno));
2122     errno = safe_errno;
2123
2124     return FALSE;
2125 }
2126
2127 DeviceStatusFlags tape_is_tape_device(int fd) {
2128     struct mtop mt;
2129     mt.mt_op = MTNOP;
2130     mt.mt_count = 1;
2131     if (0 == ioctl(fd, MTIOCTOP, &mt)) {
2132         return DEVICE_STATUS_SUCCESS;
2133 #ifdef ENOMEDIUM
2134     } else if (errno == ENOMEDIUM) {
2135         return DEVICE_STATUS_VOLUME_MISSING;
2136 #endif
2137     } else {
2138         g_debug("tape_is_tape_device: ioctl(MTIOCTOP/MTNOP) failed: %s",
2139                  strerror(errno));
2140         if (errno == EIO) {
2141             /* some devices return EIO while the drive is busy loading */
2142             return DEVICE_STATUS_DEVICE_ERROR|DEVICE_STATUS_DEVICE_BUSY;
2143         } else {
2144             return DEVICE_STATUS_DEVICE_ERROR;
2145         }
2146     }
2147 }
2148
2149 DeviceStatusFlags tape_is_ready(int fd, TapeDevice *t_self G_GNUC_UNUSED) {
2150     struct mtget get;
2151     if (0 == ioctl(fd, MTIOCGET, &get)) {
2152 #if defined(GMT_ONLINE) || defined(GMT_DR_OPEN)
2153         if (1
2154 #ifdef GMT_ONLINE
2155             && (t_self->broken_gmt_online || GMT_ONLINE(get.mt_gstat))
2156 #endif
2157 #ifdef GMT_DR_OPEN
2158             && !GMT_DR_OPEN(get.mt_gstat)
2159 #endif
2160             ) {
2161             return DEVICE_STATUS_SUCCESS;
2162         } else {
2163             return DEVICE_STATUS_VOLUME_MISSING;
2164         }
2165 #else /* Neither macro is defined. */
2166         return DEVICE_STATUS_SUCCESS;
2167 #endif
2168     } else {
2169         return DEVICE_STATUS_VOLUME_ERROR;
2170     }
2171 }
2172