apps/plugin.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2002 Björn Stenberg
  11  *
  12  * All files in this archive are subject to the GNU General Public License.
  13  * See the file COPYING in the source tree root for full license agreement.
  14  *
  15  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  16  * KIND, either express or implied.
  17  *
  18  ****************************************************************************/
  19 #include "plugin.h"
  20 #include <ctype.h>
  21 #include <string.h>
  22 #include <sprintf.h>
  23 #include <atoi.h>
  24 #include "debug.h"
  25 #include "i2c.h"
  26 #include "lang.h"
  27 #include "led.h"
  28 #include "keyboard.h"
  29 #include "buffer.h"
  30 #include "backlight.h"
  31 #include "sound_menu.h"
  32 #include "mp3data.h"
  33 #include "powermgmt.h"
  34 #include "splash.h"
  35 #include "logf.h"
  36 #include "option_select.h"
  37
  38 #if CONFIG_CHARGING
  39 #include "power.h"
  40 #endif
  41
  42 #ifdef HAVE_LCD_BITMAP
  43 #include "scrollbar.h"
  44 #include "peakmeter.h"
  45 #include "bmp.h"
  46 #include "bidi.h"
  47 #endif
  48
  49 #ifdef SIMULATOR
  50 static unsigned char pluginbuf[PLUGIN_BUFFER_SIZE];
  51 void *sim_plugin_load(char *plugin, void **pd);
  52 void sim_plugin_close(void *pd);
  53 void sim_lcd_ex_init(int shades, unsigned long (*getpixel)(int, int));
  54 void sim_lcd_ex_update_rect(int x, int y, int width, int height);
  55 #else
  56 #define sim_plugin_close(x)
  57 extern unsigned char pluginbuf[];
  58 #include "bitswap.h"
  59 #endif
  60
  61 /* for actual plugins only, not for codecs */
  62 static bool plugin_loaded = false;
  63 static int  plugin_size = 0;
  64 static bool (*pfn_tsr_exit)(bool reenter) = NULL; /* TSR exit callback */
  65 static char current_plugin[MAX_PATH];
  66
  67 extern struct thread_entry threads[MAXTHREADS];
  68
  69 static const struct plugin_api rockbox_api = {
  70
  71     /* lcd */
  72     lcd_set_contrast,
  73     lcd_update,
  74     lcd_clear_display,
  75     lcd_setmargins,
  76     lcd_getstringsize,
  77     lcd_putsxy,
  78     lcd_puts,
  79     lcd_puts_scroll,
  80     lcd_stop_scroll,
  81 #ifdef HAVE_LCD_CHARCELLS
  82     lcd_define_pattern,
  83     lcd_get_locked_pattern,
  84     lcd_unlock_pattern,
  85     lcd_putc,
  86     lcd_put_cursor,
  87     lcd_remove_cursor,
  88     lcd_icon,
  89     lcd_double_height,
  90 #else
  91     lcd_set_drawmode,
  92     lcd_get_drawmode,
  93     lcd_setfont,
  94     lcd_drawpixel,
  95     lcd_drawline,
  96     lcd_hline,
  97     lcd_vline,
  98     lcd_drawrect,
  99     lcd_fillrect,
 100     lcd_mono_bitmap_part,
 101     lcd_mono_bitmap,
 102 #if LCD_DEPTH > 1
 103     lcd_set_foreground,
 104     lcd_get_foreground,
 105     lcd_set_background,
 106     lcd_get_background,
 107     lcd_bitmap_part,
 108     lcd_bitmap,
 109     lcd_get_backdrop,
 110     lcd_set_backdrop,
 111 #endif
 112 #if LCD_DEPTH == 16
 113     lcd_bitmap_transparent_part,
 114     lcd_bitmap_transparent,
 115 #endif
 116     bidi_l2v,
 117     font_get_bits,
 118     font_load,
 119     lcd_puts_style,
 120     lcd_puts_scroll_style,
 121     &lcd_framebuffer[0][0],
 122     lcd_blit,
 123     lcd_update_rect,
 124     gui_scrollbar_draw,
 125     font_get,
 126     font_getstringsize,
 127     font_get_width,
 128 #endif
 129     backlight_on,
 130     backlight_off,
 131     backlight_set_timeout,
 132     gui_syncsplash,
 133 #ifdef HAVE_REMOTE_LCD
 134     /* remote lcd */
 135     lcd_remote_set_contrast,
 136     lcd_remote_clear_display,
 137     lcd_remote_puts,
 138     lcd_remote_puts_scroll,
 139     lcd_remote_stop_scroll,
 140     lcd_remote_set_drawmode,
 141     lcd_remote_get_drawmode,
 142     lcd_remote_setfont,
 143     lcd_remote_getstringsize,
 144     lcd_remote_drawpixel,
 145     lcd_remote_drawline,
 146     lcd_remote_hline,
 147     lcd_remote_vline,
 148     lcd_remote_drawrect,
 149     lcd_remote_fillrect,
 150     lcd_remote_mono_bitmap_part,
 151     lcd_remote_mono_bitmap,
 152     lcd_remote_putsxy,
 153     lcd_remote_puts_style,
 154     lcd_remote_puts_scroll_style,
 155     &lcd_remote_framebuffer[0][0],
 156     lcd_remote_update,
 157     lcd_remote_update_rect,
 158
 159     remote_backlight_on,
 160     remote_backlight_off,
 161 #endif
 162 #if NB_SCREENS == 2
 163     {&screens[SCREEN_MAIN], &screens[SCREEN_REMOTE]},
 164 #else
 165     {&screens[SCREEN_MAIN]},
 166 #endif
 167 #if defined(HAVE_REMOTE_LCD) && (LCD_REMOTE_DEPTH > 1)
 168     lcd_remote_set_foreground,
 169     lcd_remote_get_foreground,
 170     lcd_remote_set_background,
 171     lcd_remote_get_background,
 172     lcd_remote_bitmap_part,
 173     lcd_remote_bitmap,
 174 #endif
 175
 176 #if defined(HAVE_LCD_COLOR) && !defined(SIMULATOR)
 177     lcd_yuv_blit,
 178 #endif
 179     /* list */
 180     gui_synclist_init,
 181     gui_synclist_set_nb_items,
 182     gui_synclist_set_icon_callback,
 183     gui_synclist_get_nb_items,
 184     gui_synclist_get_sel_pos,
 185     gui_synclist_draw,
 186     gui_synclist_select_item,
 187     gui_synclist_add_item,
 188     gui_synclist_del_item,
 189     gui_synclist_limit_scroll,
 190     gui_synclist_flash,
 191     gui_synclist_do_button,
 192     gui_synclist_set_title,
 193
 194     /* button */
 195     button_get,
 196     button_get_w_tmo,
 197     button_status,
 198     button_clear_queue,
 199 #ifdef HAS_BUTTON_HOLD
 200     button_hold,
 201 #endif
 202
 203     /* file */
 204     (open_func)PREFIX(open),
 205     close,
 206     (read_func)read,
 207     PREFIX(lseek),
 208     (creat_func)PREFIX(creat),
 209     (write_func)write,
 210     PREFIX(remove),
 211     PREFIX(rename),
 212     PREFIX(ftruncate),
 213     PREFIX(filesize),
 214     fdprintf,
 215     read_line,
 216     settings_parseline,
 217 #ifndef SIMULATOR
 218     ata_sleep,
 219     ata_disk_is_active,
 220 #endif
 221     ata_spindown,
 222     reload_directory,
 223     create_numbered_filename,
 224
 225     /* dir */
 226     opendir,
 227     closedir,
 228     readdir,
 229     mkdir,
 230     rmdir,
 231
 232     /* kernel/ system */
 233     PREFIX(sleep),
 234     yield,
 235 #ifdef HAVE_PRIORITY_SCHEDULING
 236     priority_yield,
 237 #endif
 238     &current_tick,
 239     default_event_handler,
 240     default_event_handler_ex,
 241     threads,
 242     create_thread,
 243     remove_thread,
 244     reset_poweroff_timer,
 245 #ifndef SIMULATOR
 246     system_memory_guard,
 247     &cpu_frequency,
 248
 249 #ifdef HAVE_ADJUSTABLE_CPU_FREQ
 250 #ifdef CPU_BOOST_LOGGING
 251     cpu_boost_,
 252 #else
 253     cpu_boost,
 254 #endif
 255 #endif
 256 #endif
 257     timer_register,
 258     timer_unregister,
 259     timer_set_period,
 260
 261     queue_init,
 262     queue_delete,
 263     queue_post,
 264     queue_wait_w_tmo,
 265     usb_acknowledge,
 266 #ifdef RB_PROFILE
 267     profile_thread,
 268     profstop,
 269     profile_func_enter,
 270     profile_func_exit,
 271 #endif
 272
 273 #ifdef SIMULATOR
 274     /* special simulator hooks */
 275 #if defined(HAVE_LCD_BITMAP) && LCD_DEPTH < 8
 276     sim_lcd_ex_init,
 277     sim_lcd_ex_update_rect,
 278 #endif
 279 #endif
 280
 281     /* strings and memory */
 282     snprintf,
 283     vsnprintf,
 284     strcpy,
 285     strncpy,
 286     strlen,
 287     strrchr,
 288     strcmp,
 289     strncmp,
 290     strcasecmp,
 291     strncasecmp,
 292     memset,
 293     memcpy,
 294     memmove,
 295     _ctype_,
 296     atoi,
 297     strchr,
 298     strcat,
 299     memchr,
 300     memcmp,
 301     strcasestr,
 302     strtok_r,
 303     /* unicode stuff */
 304     utf8decode,
 305     iso_decode,
 306     utf16LEdecode,
 307     utf16BEdecode,
 308     utf8encode,
 309     utf8length,
 310     utf8seek,
 311
 312     /* sound */
 313 #if CONFIG_CODEC == SWCODEC
 314     sound_default,
 315 #endif
 316     sound_set,
 317
 318     sound_min,
 319     sound_max,
 320 #ifndef SIMULATOR
 321     mp3_play_data,
 322     mp3_play_pause,
 323     mp3_play_stop,
 324     mp3_is_playing,
 325 #if CONFIG_CODEC != SWCODEC
 326     bitswap,
 327 #endif
 328 #endif
 329 #if CONFIG_CODEC == SWCODEC
 330     &audio_master_sampr_list[0],
 331     &hw_freq_sampr[0],
 332     pcm_apply_settings,
 333     pcm_play_data,
 334     pcm_play_stop,
 335     pcm_set_frequency,
 336     pcm_is_playing,
 337     pcm_is_paused,
 338     pcm_play_pause,
 339     pcm_get_bytes_waiting,
 340     pcm_calculate_peaks,
 341 #ifdef HAVE_RECORDING
 342     &rec_freq_sampr[0],
 343     pcm_init_recording,
 344     pcm_close_recording,
 345     pcm_record_data,
 346     pcm_record_more,
 347     pcm_stop_recording,
 348     pcm_calculate_rec_peaks,
 349     audio_set_recording_gain,
 350 #endif /* HAVE_RECORDING */
 351 #if INPUT_SRC_CAPS != 0
 352     audio_set_output_source,
 353     audio_set_input_source,
 354 #endif
 355 #endif /* CONFIG_CODEC == SWCODEC */
 356
 357     /* playback control */
 358     playlist_amount,
 359     playlist_resume,
 360     playlist_start,
 361     PREFIX(audio_play),
 362     audio_stop,
 363     audio_pause,
 364     audio_resume,
 365     audio_next,
 366     audio_prev,
 367     audio_ff_rewind,
 368     audio_next_track,
 369     audio_status,
 370     audio_has_changed_track,
 371     audio_current_track,
 372     audio_flush_and_reload_tracks,
 373     audio_get_file_pos,
 374 #if !defined(SIMULATOR) && (CONFIG_CODEC != SWCODEC)
 375     mpeg_get_last_header,
 376 #endif
 377 #if (CONFIG_CODEC == MAS3587F) || (CONFIG_CODEC == MAS3539F) || \
 378     (CONFIG_CODEC == SWCODEC)
 379     sound_set_pitch,
 380 #endif
 381
 382 #if !defined(SIMULATOR) && (CONFIG_CODEC != SWCODEC)
 383     /* MAS communication */
 384     mas_readmem,
 385     mas_writemem,
 386     mas_readreg,
 387     mas_writereg,
 388 #if (CONFIG_CODEC == MAS3587F) || (CONFIG_CODEC == MAS3539F)
 389     mas_codec_writereg,
 390     mas_codec_readreg,
 391     i2c_begin,
 392     i2c_end,
 393     i2c_write,
 394 #endif
 395 #endif /* !SIMULATOR && CONFIG_CODEC != SWCODEC */
 396
 397     /* menu */
 398     do_menu,
 399     /* statusbars */
 400     &statusbars,
 401     gui_syncstatusbar_draw,
 402     /* options */
 403     find_setting,
 404     option_screen,
 405     set_option,
 406     set_bool_options,
 407     set_int,
 408     set_bool,
 409 #ifdef HAVE_LCD_COLOR
 410     set_color,
 411 #endif
 412
 413     /* action handling */
 414     get_custom_action,
 415     get_action,
 416     action_userabort,
 417
 418     /* power */
 419     battery_level,
 420     battery_level_safe,
 421     battery_time,
 422 #ifndef SIMULATOR
 423     battery_voltage,
 424 #endif
 425 #if CONFIG_CHARGING
 426     charger_inserted,
 427 # if CONFIG_CHARGING == CHARGING_MONITOR
 428     charging_state,
 429 # endif
 430 #endif
 431 #ifdef HAVE_USB_POWER
 432         usb_powered,
 433 #endif
 434
 435     /* misc */
 436     srand,
 437     rand,
 438     (qsort_func)qsort,
 439     kbd_input,
 440     get_time,
 441     set_time,
 442 #if CONFIG_RTC
 443     mktime,
 444 #endif
 445     plugin_get_buffer,
 446     plugin_get_audio_buffer,
 447     plugin_tsr,
 448 #ifdef IRAM_STEAL
 449     plugin_iram_init,
 450 #endif
 451 #if defined(DEBUG) || defined(SIMULATOR)
 452     debugf,
 453 #endif
 454 #ifdef ROCKBOX_HAS_LOGF
 455     _logf,
 456 #endif
 457     &global_settings,
 458     &global_status,
 459     mp3info,
 460     count_mp3_frames,
 461     create_xing_header,
 462     find_next_frame,
 463 #if (CONFIG_CODEC == MAS3587F) || (CONFIG_CODEC == MAS3539F)
 464     peak_meter_scale_value,
 465     peak_meter_set_use_dbfs,
 466     peak_meter_get_use_dbfs,
 467 #endif
 468 #ifdef HAVE_LCD_BITMAP
 469     read_bmp_file,
 470     screen_dump_set_hook,
 471 #endif
 472     show_logo,
 473     tree_get_context,
 474
 475 #ifdef HAVE_WHEEL_POSITION
 476     wheel_status,
 477     wheel_send_events,
 478 #endif
 479
 480 #ifdef IRIVER_H100_SERIES
 481     /* Routines for the iriver_flash -plugin. */
 482     detect_original_firmware,
 483     detect_flashed_ramimage,
 484     detect_flashed_romimage,
 485 #endif
 486     /* new stuff at the end, sort into place next time
 487        the API gets incompatible */
 488
 489 #if (CONFIG_CODEC == SWCODEC)
 490     spinlock_init,
 491     spinlock_lock,
 492     spinlock_unlock,
 493
 494     codec_load_file,
 495     get_codec_filename,
 496     get_metadata,
 497 #endif
 498 #ifdef HAVE_LCD_BITMAP
 499     screen_clear_area,
 500 #endif
 501     led,
 502     set_current_file,
 503     set_dirfilter,
 504 };
 505
 506 int plugin_load(const char* plugin, void* parameter)
 507 {
 508     int rc;
 509     struct plugin_header *hdr;
 510     const char *p = strrchr(plugin,'/');
 511 #ifdef SIMULATOR
 512     void *pd;
 513 #else
 514     int fd;
 515     ssize_t readsize;
 516 #endif
 517     int xm, ym;
 518 #ifdef HAVE_REMOTE_LCD
 519     int rxm, rym;
 520 #endif
 521
 522 #if LCD_DEPTH > 1
 523     fb_data* old_backdrop;
 524 #endif
 525
 526     if (!p)
 527         p = plugin;
 528
 529     if (pfn_tsr_exit != NULL) /* if we have a resident old plugin: */
 530     {
 531         if (pfn_tsr_exit(!strcmp(current_plugin,p)) == false )
 532         {
 533             /* not allowing another plugin to load */
 534             return PLUGIN_OK;
 535         }
 536         pfn_tsr_exit = NULL;
 537         plugin_loaded = false;
 538     }
 539
 540     gui_syncsplash(0, str(LANG_WAIT));
 541     strcpy(current_plugin,p);
 542
 543 #ifdef SIMULATOR
 544     hdr = sim_plugin_load((char *)plugin, &pd);
 545     if (pd == NULL) {
 546         gui_syncsplash(HZ*2, str(LANG_PLUGIN_CANT_OPEN), plugin);
 547         return -1;
 548     }
 549     if (hdr == NULL
 550         || hdr->magic != PLUGIN_MAGIC
 551         || hdr->target_id != TARGET_ID) {
 552         sim_plugin_close(pd);
 553         gui_syncsplash(HZ*2, str(LANG_PLUGIN_WRONG_MODEL));
 554         return -1;
 555     }
 556     if (hdr->api_version > PLUGIN_API_VERSION
 557         || hdr->api_version < PLUGIN_MIN_API_VERSION) {
 558         sim_plugin_close(pd);
 559         gui_syncsplash(HZ*2, str(LANG_PLUGIN_WRONG_VERSION));
 560         return -1;
 561     }
 562 #else
 563     fd = open(plugin, O_RDONLY);
 564     if (fd < 0) {
 565         gui_syncsplash(HZ*2, str(LANG_PLUGIN_CANT_OPEN), plugin);
 566         return fd;
 567     }
 568
 569     readsize = read(fd, pluginbuf, PLUGIN_BUFFER_SIZE);
 570     close(fd);
 571
 572     if (readsize < 0) {
 573         gui_syncsplash(HZ*2, str(LANG_READ_FAILED), plugin);
 574         return -1;
 575     }
 576     hdr = (struct plugin_header *)pluginbuf;
 577
 578     if ((unsigned)readsize <= sizeof(struct plugin_header)
 579         || hdr->magic != PLUGIN_MAGIC
 580         || hdr->target_id != TARGET_ID
 581         || hdr->load_addr != pluginbuf
 582         || hdr->end_addr > pluginbuf + PLUGIN_BUFFER_SIZE) {
 583         gui_syncsplash(HZ*2, str(LANG_PLUGIN_WRONG_MODEL));
 584         return -1;
 585     }
 586     if (hdr->api_version > PLUGIN_API_VERSION
 587         || hdr->api_version < PLUGIN_MIN_API_VERSION) {
 588         gui_syncsplash(HZ*2, str(LANG_PLUGIN_WRONG_VERSION));
 589         return -1;
 590     }
 591     plugin_size = hdr->end_addr - pluginbuf;
 592
 593     /* zero out bss area only, above guards end of pluginbuf */
 594     if (plugin_size > readsize)
 595         memset(pluginbuf + readsize, 0, plugin_size - readsize);
 596 #endif
 597
 598     plugin_loaded = true;
 599
 600     xm = lcd_getxmargin();
 601     ym = lcd_getymargin();
 602     lcd_setmargins(0,0);
 603
 604 #if defined HAVE_LCD_BITMAP && LCD_DEPTH > 1
 605     old_backdrop = lcd_get_backdrop();
 606 #endif
 607     lcd_clear_display();
 608     lcd_update();
 609
 610 #ifdef HAVE_REMOTE_LCD
 611     rxm = lcd_remote_getxmargin();
 612     rym = lcd_remote_getymargin();
 613     lcd_remote_setmargins(0, 0);
 614     lcd_remote_clear_display();
 615     lcd_remote_update();
 616 #endif
 617
 618     invalidate_icache();
 619
 620     rc = hdr->entry_point((struct plugin_api*) &rockbox_api, parameter);
 621     /* explicitly casting the pointer here to avoid touching every plugin. */
 622
 623     button_clear_queue();
 624
 625 #ifdef HAVE_LCD_BITMAP
 626 #if LCD_DEPTH > 1
 627     lcd_set_backdrop(old_backdrop);
 628 #ifdef HAVE_LCD_COLOR
 629     lcd_set_drawinfo(DRMODE_SOLID, global_settings.fg_color,
 630                                    global_settings.bg_color);
 631 #else
 632     lcd_set_drawinfo(DRMODE_SOLID, LCD_DEFAULT_FG, LCD_DEFAULT_BG);
 633 #endif
 634 #else /* LCD_DEPTH == 1 */
 635     lcd_set_drawmode(DRMODE_SOLID);
 636 #endif /* LCD_DEPTH */
 637 #endif /* HAVE_LCD_BITMAP */
 638
 639     /* restore margins */
 640     lcd_setmargins(xm,ym);
 641     lcd_clear_display();
 642     lcd_update();
 643
 644 #ifdef HAVE_REMOTE_LCD
 645 #if LCD_REMOTE_DEPTH > 1
 646     lcd_remote_set_drawinfo(DRMODE_SOLID, LCD_REMOTE_DEFAULT_FG,
 647                             LCD_REMOTE_DEFAULT_BG);
 648 #else
 649     lcd_remote_set_drawmode(DRMODE_SOLID);
 650 #endif
 651     lcd_remote_setmargins(rxm, rym);
 652     lcd_remote_clear_display();
 653     lcd_remote_update();
 654 #endif
 655
 656     if (pfn_tsr_exit == NULL)
 657         plugin_loaded = false;
 658
 659     sim_plugin_close(pd);
 660
 661     switch (rc) {
 662         case PLUGIN_OK:
 663             break;
 664
 665         case PLUGIN_USB_CONNECTED:
 666             return PLUGIN_USB_CONNECTED;
 667
 668         default:
 669             gui_syncsplash(HZ*2, str(LANG_PLUGIN_ERROR));
 670             break;
 671     }
 672     return PLUGIN_OK;
 673 }
 674
 675 /* Returns a pointer to the portion of the plugin buffer that is not already
 676    being used.  If no plugin is loaded, returns the entire plugin buffer */
 677 void* plugin_get_buffer(size_t *buffer_size)
 678 {
 679     int buffer_pos;
 680
 681     if (plugin_loaded)
 682     {
 683         if (plugin_size >= PLUGIN_BUFFER_SIZE)
 684             return NULL;
 685
 686         *buffer_size = PLUGIN_BUFFER_SIZE-plugin_size;
 687         buffer_pos = plugin_size;
 688     }
 689     else
 690     {
 691         *buffer_size = PLUGIN_BUFFER_SIZE;
 692         buffer_pos = 0;
 693     }
 694
 695     return &pluginbuf[buffer_pos];
 696 }
 697
 698 /* Returns a pointer to the mp3 buffer.
 699    Playback gets stopped, to avoid conflicts.
 700    Talk buffer is stolen as well.
 701  */
 702 void* plugin_get_audio_buffer(size_t *buffer_size)
 703 {
 704 #if CONFIG_CODEC == SWCODEC
 705     return audio_get_buffer(true, buffer_size);
 706 #else
 707     audio_stop();
 708     talk_buffer_steal(); /* we use the mp3 buffer, need to tell */
 709     *buffer_size = audiobufend - audiobuf;
 710     return audiobuf;
 711 #endif
 712 }
 713
 714 #ifdef IRAM_STEAL
 715 /* Initializes plugin IRAM */
 716 void plugin_iram_init(char *iramstart, char *iramcopy, size_t iram_size,
 717                       char *iedata, size_t iedata_size)
 718 {
 719     audio_iram_steal();
 720     memcpy(iramstart, iramcopy, iram_size);
 721     memset(iedata, 0, iedata_size);
 722     memset(iramcopy, 0, iram_size);
 723 #if NUM_CORES > 1
 724     /* writeback cleared iedata and iramcopy areas */
 725     flush_icache();
 726 #endif
 727 }
 728 #endif /* IRAM_STEAL */
 729
 730 /* The plugin wants to stay resident after leaving its main function, e.g.
 731    runs from timer or own thread. The callback is registered to later
 732    instruct it to free its resources before a new plugin gets loaded. */
 733 void plugin_tsr(bool (*exit_callback)(bool))
 734 {
 735     pfn_tsr_exit = exit_callback; /* remember the callback for later */
 736 }