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6a0f9e82 1/*
cc2040f8 2 * Block driver for Connectix / Microsoft Virtual PC images
5fafdf24 3 *
6a0f9e82 4 * Copyright (c) 2005 Alex Beregszaszi
15d35bc5 5 * Copyright (c) 2009 Kevin Wolf <kwolf@suse.de>
5fafdf24 6 *
6a0f9e82
FB
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
23 * THE SOFTWARE.
24 */
faf07963 25#include "qemu-common.h"
6a0f9e82 26#include "block_int.h"
5efa9d5a 27#include "module.h"
6a0f9e82
FB
28
29/**************************************************************/
30
31#define HEADER_SIZE 512
32
33//#define CACHE
34
2cfacb62
AL
35enum vhd_type {
36 VHD_FIXED = 2,
37 VHD_DYNAMIC = 3,
38 VHD_DIFFERENCING = 4,
39};
40
57c7d9e5
AL
41// Seconds since Jan 1, 2000 0:00:00 (UTC)
42#define VHD_TIMESTAMP_BASE 946684800
43
6a0f9e82 44// always big-endian
b9fa33a6 45struct vhd_footer {
2cfacb62
AL
46 char creator[8]; // "conectix"
47 uint32_t features;
48 uint32_t version;
49
50 // Offset of next header structure, 0xFFFFFFFF if none
51 uint64_t data_offset;
52
53 // Seconds since Jan 1, 2000 0:00:00 (UTC)
54 uint32_t timestamp;
55
56 char creator_app[4]; // "vpc "
57 uint16_t major;
58 uint16_t minor;
59 char creator_os[4]; // "Wi2k"
60
61 uint64_t orig_size;
62 uint64_t size;
63
64 uint16_t cyls;
65 uint8_t heads;
66 uint8_t secs_per_cyl;
67
68 uint32_t type;
69
70 // Checksum of the Hard Disk Footer ("one's complement of the sum of all
71 // the bytes in the footer without the checksum field")
72 uint32_t checksum;
73
74 // UUID used to identify a parent hard disk (backing file)
75 uint8_t uuid[16];
76
77 uint8_t in_saved_state;
b9fa33a6
AL
78};
79
80struct vhd_dyndisk_header {
2cfacb62
AL
81 char magic[8]; // "cxsparse"
82
83 // Offset of next header structure, 0xFFFFFFFF if none
84 uint64_t data_offset;
85
86 // Offset of the Block Allocation Table (BAT)
87 uint64_t table_offset;
88
89 uint32_t version;
90 uint32_t max_table_entries; // 32bit/entry
91
92 // 2 MB by default, must be a power of two
93 uint32_t block_size;
94
95 uint32_t checksum;
96 uint8_t parent_uuid[16];
97 uint32_t parent_timestamp;
98 uint32_t reserved;
99
100 // Backing file name (in UTF-16)
101 uint8_t parent_name[512];
102
103 struct {
104 uint32_t platform;
105 uint32_t data_space;
106 uint32_t data_length;
107 uint32_t reserved;
108 uint64_t data_offset;
109 } parent_locator[8];
6a0f9e82
FB
110};
111
112typedef struct BDRVVPCState {
b71d1c2e 113 BlockDriverState *hd;
3b46e624 114
15d35bc5
AL
115 uint8_t footer_buf[HEADER_SIZE];
116 uint64_t free_data_block_offset;
2cfacb62 117 int max_table_entries;
6a0f9e82 118 uint32_t *pagetable;
15d35bc5
AL
119 uint64_t bat_offset;
120 uint64_t last_bitmap_offset;
6a0f9e82 121
2cfacb62 122 uint32_t block_size;
15d35bc5
AL
123 uint32_t bitmap_size;
124
6a0f9e82
FB
125#ifdef CACHE
126 uint8_t *pageentry_u8;
127 uint32_t *pageentry_u32;
128 uint16_t *pageentry_u16;
3b46e624 129
6a0f9e82
FB
130 uint64_t last_bitmap;
131#endif
132} BDRVVPCState;
133
57c7d9e5
AL
134static uint32_t vpc_checksum(uint8_t* buf, size_t size)
135{
136 uint32_t res = 0;
137 int i;
138
139 for (i = 0; i < size; i++)
140 res += buf[i];
141
142 return ~res;
143}
144
145
6a0f9e82
FB
146static int vpc_probe(const uint8_t *buf, int buf_size, const char *filename)
147{
ffe8ab83 148 if (buf_size >= 8 && !strncmp((char *)buf, "conectix", 8))
6a0f9e82 149 return 100;
6a0f9e82
FB
150 return 0;
151}
152
83f64091 153static int vpc_open(BlockDriverState *bs, const char *filename, int flags)
6a0f9e82
FB
154{
155 BDRVVPCState *s = bs->opaque;
b71d1c2e 156 int ret, i;
b9fa33a6
AL
157 struct vhd_footer* footer;
158 struct vhd_dyndisk_header* dyndisk_header;
159 uint8_t buf[HEADER_SIZE];
57c7d9e5 160 uint32_t checksum;
6a0f9e82 161
b71d1c2e
AL
162 ret = bdrv_file_open(&s->hd, filename, flags);
163 if (ret < 0)
164 return ret;
6a0f9e82 165
15d35bc5 166 if (bdrv_pread(s->hd, 0, s->footer_buf, HEADER_SIZE) != HEADER_SIZE)
6a0f9e82
FB
167 goto fail;
168
15d35bc5 169 footer = (struct vhd_footer*) s->footer_buf;
b9fa33a6 170 if (strncmp(footer->creator, "conectix", 8))
6a0f9e82 171 goto fail;
6a0f9e82 172
57c7d9e5
AL
173 checksum = be32_to_cpu(footer->checksum);
174 footer->checksum = 0;
175 if (vpc_checksum(s->footer_buf, HEADER_SIZE) != checksum)
176 fprintf(stderr, "block-vpc: The header checksum of '%s' is "
177 "incorrect.\n", filename);
178
1fa79228
AL
179 // The visible size of a image in Virtual PC depends on the geometry
180 // rather than on the size stored in the footer (the size in the footer
181 // is too large usually)
182 bs->total_sectors = (int64_t)
183 be16_to_cpu(footer->cyls) * footer->heads * footer->secs_per_cyl;
184
b71d1c2e
AL
185 if (bdrv_pread(s->hd, be64_to_cpu(footer->data_offset), buf, HEADER_SIZE)
186 != HEADER_SIZE)
6a0f9e82
FB
187 goto fail;
188
b9fa33a6
AL
189 dyndisk_header = (struct vhd_dyndisk_header*) buf;
190
191 if (strncmp(dyndisk_header->magic, "cxsparse", 8))
192 goto fail;
6a0f9e82 193
6a0f9e82 194
15d35bc5
AL
195 s->block_size = be32_to_cpu(dyndisk_header->block_size);
196 s->bitmap_size = ((s->block_size / (8 * 512)) + 511) & ~511;
197
2cfacb62
AL
198 s->max_table_entries = be32_to_cpu(dyndisk_header->max_table_entries);
199 s->pagetable = qemu_malloc(s->max_table_entries * 4);
b71d1c2e 200
15d35bc5
AL
201 s->bat_offset = be64_to_cpu(dyndisk_header->table_offset);
202 if (bdrv_pread(s->hd, s->bat_offset, s->pagetable,
203 s->max_table_entries * 4) != s->max_table_entries * 4)
b71d1c2e
AL
204 goto fail;
205
15d35bc5
AL
206 s->free_data_block_offset =
207 (s->bat_offset + (s->max_table_entries * 4) + 511) & ~511;
208
209 for (i = 0; i < s->max_table_entries; i++) {
210 be32_to_cpus(&s->pagetable[i]);
211 if (s->pagetable[i] != 0xFFFFFFFF) {
212 int64_t next = (512 * (int64_t) s->pagetable[i]) +
213 s->bitmap_size + s->block_size;
214
215 if (next> s->free_data_block_offset)
216 s->free_data_block_offset = next;
217 }
218 }
219
220 s->last_bitmap_offset = (int64_t) -1;
6a0f9e82 221
6a0f9e82
FB
222#ifdef CACHE
223 s->pageentry_u8 = qemu_malloc(512);
6a0f9e82
FB
224 s->pageentry_u32 = s->pageentry_u8;
225 s->pageentry_u16 = s->pageentry_u8;
226 s->last_pagetable = -1;
227#endif
228
229 return 0;
230 fail:
b71d1c2e 231 bdrv_delete(s->hd);
6a0f9e82
FB
232 return -1;
233}
234
b71d1c2e
AL
235/*
236 * Returns the absolute byte offset of the given sector in the image file.
237 * If the sector is not allocated, -1 is returned instead.
15d35bc5
AL
238 *
239 * The parameter write must be 1 if the offset will be used for a write
240 * operation (the block bitmaps is updated then), 0 otherwise.
b71d1c2e 241 */
15d35bc5
AL
242static inline int64_t get_sector_offset(BlockDriverState *bs,
243 int64_t sector_num, int write)
6a0f9e82
FB
244{
245 BDRVVPCState *s = bs->opaque;
246 uint64_t offset = sector_num * 512;
247 uint64_t bitmap_offset, block_offset;
248 uint32_t pagetable_index, pageentry_index;
249
2cfacb62
AL
250 pagetable_index = offset / s->block_size;
251 pageentry_index = (offset % s->block_size) / 512;
3b46e624 252
15d35bc5
AL
253 if (pagetable_index >= s->max_table_entries || s->pagetable[pagetable_index] == 0xffffffff)
254 return -1; // not allocated
6a0f9e82 255
378e2aea 256 bitmap_offset = 512 * (uint64_t) s->pagetable[pagetable_index];
15d35bc5
AL
257 block_offset = bitmap_offset + s->bitmap_size + (512 * pageentry_index);
258
259 // We must ensure that we don't write to any sectors which are marked as
260 // unused in the bitmap. We get away with setting all bits in the block
261 // bitmap each time we write to a new block. This might cause Virtual PC to
262 // miss sparse read optimization, but it's not a problem in terms of
263 // correctness.
264 if (write && (s->last_bitmap_offset != bitmap_offset)) {
265 uint8_t bitmap[s->bitmap_size];
266
267 s->last_bitmap_offset = bitmap_offset;
268 memset(bitmap, 0xff, s->bitmap_size);
269 bdrv_pwrite(s->hd, bitmap_offset, bitmap, s->bitmap_size);
270 }
3b46e624 271
26a76461 272// printf("sector: %" PRIx64 ", index: %x, offset: %x, bioff: %" PRIx64 ", bloff: %" PRIx64 "\n",
6a0f9e82
FB
273// sector_num, pagetable_index, pageentry_index,
274// bitmap_offset, block_offset);
275
276// disabled by reason
277#if 0
278#ifdef CACHE
279 if (bitmap_offset != s->last_bitmap)
280 {
281 lseek(s->fd, bitmap_offset, SEEK_SET);
282
283 s->last_bitmap = bitmap_offset;
5fafdf24 284
6a0f9e82
FB
285 // Scary! Bitmap is stored as big endian 32bit entries,
286 // while we used to look it up byte by byte
287 read(s->fd, s->pageentry_u8, 512);
288 for (i = 0; i < 128; i++)
289 be32_to_cpus(&s->pageentry_u32[i]);
290 }
291
292 if ((s->pageentry_u8[pageentry_index / 8] >> (pageentry_index % 8)) & 1)
293 return -1;
294#else
295 lseek(s->fd, bitmap_offset + (pageentry_index / 8), SEEK_SET);
5fafdf24 296
6a0f9e82
FB
297 read(s->fd, &bitmap_entry, 1);
298
299 if ((bitmap_entry >> (pageentry_index % 8)) & 1)
300 return -1; // not allocated
301#endif
302#endif
6a0f9e82 303
b71d1c2e 304 return block_offset;
6a0f9e82
FB
305}
306
15d35bc5
AL
307/*
308 * Writes the footer to the end of the image file. This is needed when the
309 * file grows as it overwrites the old footer
310 *
311 * Returns 0 on success and < 0 on error
312 */
313static int rewrite_footer(BlockDriverState* bs)
314{
315 int ret;
316 BDRVVPCState *s = bs->opaque;
317 int64_t offset = s->free_data_block_offset;
318
319 ret = bdrv_pwrite(s->hd, offset, s->footer_buf, HEADER_SIZE);
320 if (ret < 0)
321 return ret;
322
323 return 0;
324}
325
326/*
327 * Allocates a new block. This involves writing a new footer and updating
328 * the Block Allocation Table to use the space at the old end of the image
329 * file (overwriting the old footer)
330 *
331 * Returns the sectors' offset in the image file on success and < 0 on error
332 */
333static int64_t alloc_block(BlockDriverState* bs, int64_t sector_num)
334{
335 BDRVVPCState *s = bs->opaque;
336 int64_t bat_offset;
337 uint32_t index, bat_value;
338 int ret;
339 uint8_t bitmap[s->bitmap_size];
340
341 // Check if sector_num is valid
342 if ((sector_num < 0) || (sector_num > bs->total_sectors))
343 return -1;
344
345 // Write entry into in-memory BAT
346 index = (sector_num * 512) / s->block_size;
347 if (s->pagetable[index] != 0xFFFFFFFF)
348 return -1;
349
350 s->pagetable[index] = s->free_data_block_offset / 512;
351
352 // Initialize the block's bitmap
353 memset(bitmap, 0xff, s->bitmap_size);
354 bdrv_pwrite(s->hd, s->free_data_block_offset, bitmap, s->bitmap_size);
355
356 // Write new footer (the old one will be overwritten)
357 s->free_data_block_offset += s->block_size + s->bitmap_size;
358 ret = rewrite_footer(bs);
359 if (ret < 0)
360 goto fail;
361
362 // Write BAT entry to disk
363 bat_offset = s->bat_offset + (4 * index);
364 bat_value = be32_to_cpu(s->pagetable[index]);
365 ret = bdrv_pwrite(s->hd, bat_offset, &bat_value, 4);
366 if (ret < 0)
367 goto fail;
368
369 return get_sector_offset(bs, sector_num, 0);
370
371fail:
372 s->free_data_block_offset -= (s->block_size + s->bitmap_size);
373 return -1;
374}
375
5fafdf24 376static int vpc_read(BlockDriverState *bs, int64_t sector_num,
6a0f9e82
FB
377 uint8_t *buf, int nb_sectors)
378{
379 BDRVVPCState *s = bs->opaque;
380 int ret;
b71d1c2e 381 int64_t offset;
6a0f9e82
FB
382
383 while (nb_sectors > 0) {
15d35bc5 384 offset = get_sector_offset(bs, sector_num, 0);
b71d1c2e
AL
385
386 if (offset == -1) {
6a0f9e82 387 memset(buf, 0, 512);
b71d1c2e
AL
388 } else {
389 ret = bdrv_pread(s->hd, offset, buf, 512);
390 if (ret != 512)
391 return -1;
392 }
393
6a0f9e82
FB
394 nb_sectors--;
395 sector_num++;
396 buf += 512;
397 }
398 return 0;
399}
400
15d35bc5
AL
401static int vpc_write(BlockDriverState *bs, int64_t sector_num,
402 const uint8_t *buf, int nb_sectors)
403{
404 BDRVVPCState *s = bs->opaque;
405 int64_t offset;
406 int ret;
407
408 while (nb_sectors > 0) {
409 offset = get_sector_offset(bs, sector_num, 1);
410
411 if (offset == -1) {
412 offset = alloc_block(bs, sector_num);
413 if (offset < 0)
414 return -1;
415 }
416
417 ret = bdrv_pwrite(s->hd, offset, buf, 512);
418 if (ret != 512)
419 return -1;
420
421 nb_sectors--;
422 sector_num++;
423 buf += 512;
424 }
425
426 return 0;
427}
428
57c7d9e5
AL
429
430/*
431 * Calculates the number of cylinders, heads and sectors per cylinder
432 * based on a given number of sectors. This is the algorithm described
433 * in the VHD specification.
434 *
435 * Note that the geometry doesn't always exactly match total_sectors but
436 * may round it down.
6e9ea0c0
AJ
437 *
438 * Returns 0 on success, -EFBIG if the size is larger than 127 GB
57c7d9e5 439 */
6e9ea0c0 440static int calculate_geometry(int64_t total_sectors, uint16_t* cyls,
57c7d9e5
AL
441 uint8_t* heads, uint8_t* secs_per_cyl)
442{
443 uint32_t cyls_times_heads;
444
445 if (total_sectors > 65535 * 16 * 255)
6e9ea0c0 446 return -EFBIG;
57c7d9e5
AL
447
448 if (total_sectors > 65535 * 16 * 63) {
449 *secs_per_cyl = 255;
450 *heads = 16;
451 cyls_times_heads = total_sectors / *secs_per_cyl;
452 } else {
453 *secs_per_cyl = 17;
454 cyls_times_heads = total_sectors / *secs_per_cyl;
455 *heads = (cyls_times_heads + 1023) / 1024;
456
457 if (*heads < 4)
458 *heads = 4;
459
460 if (cyls_times_heads >= (*heads * 1024) || *heads > 16) {
461 *secs_per_cyl = 31;
462 *heads = 16;
463 cyls_times_heads = total_sectors / *secs_per_cyl;
464 }
465
466 if (cyls_times_heads >= (*heads * 1024)) {
467 *secs_per_cyl = 63;
468 *heads = 16;
469 cyls_times_heads = total_sectors / *secs_per_cyl;
470 }
471 }
472
473 // Note: Rounding up deviates from the Virtual PC behaviour
474 // However, we need this to avoid truncating images in qemu-img convert
475 *cyls = (cyls_times_heads + *heads - 1) / *heads;
6e9ea0c0
AJ
476
477 return 0;
57c7d9e5
AL
478}
479
0e7e1989 480static int vpc_create(const char *filename, QEMUOptionParameter *options)
57c7d9e5
AL
481{
482 uint8_t buf[1024];
483 struct vhd_footer* footer = (struct vhd_footer*) buf;
484 struct vhd_dyndisk_header* dyndisk_header =
485 (struct vhd_dyndisk_header*) buf;
486 int fd, i;
487 uint16_t cyls;
488 uint8_t heads;
489 uint8_t secs_per_cyl;
490 size_t block_size, num_bat_entries;
0e7e1989 491 int64_t total_sectors = 0;
57c7d9e5 492
0e7e1989
KW
493 // Read out options
494 while (options && options->name) {
495 if (!strcmp(options->name, "size")) {
496 total_sectors = options->value.n / 512;
497 }
498 options++;
499 }
57c7d9e5 500
0e7e1989 501 // Create the file
57c7d9e5
AL
502 fd = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0644);
503 if (fd < 0)
504 return -EIO;
505
506 // Calculate matching total_size and geometry
6e9ea0c0
AJ
507 if (calculate_geometry(total_sectors, &cyls, &heads, &secs_per_cyl))
508 return -EFBIG;
57c7d9e5
AL
509 total_sectors = (int64_t) cyls * heads * secs_per_cyl;
510
511 // Prepare the Hard Disk Footer
512 memset(buf, 0, 1024);
513
5ec4d682 514 memcpy(footer->creator, "conectix", 8);
57c7d9e5 515 // TODO Check if "qemu" creator_app is ok for VPC
5ec4d682
NF
516 memcpy(footer->creator_app, "qemu", 4);
517 memcpy(footer->creator_os, "Wi2k", 4);
57c7d9e5
AL
518
519 footer->features = be32_to_cpu(0x02);
520 footer->version = be32_to_cpu(0x00010000);
521 footer->data_offset = be64_to_cpu(HEADER_SIZE);
522 footer->timestamp = be32_to_cpu(time(NULL) - VHD_TIMESTAMP_BASE);
523
524 // Version of Virtual PC 2007
525 footer->major = be16_to_cpu(0x0005);
526 footer->minor =be16_to_cpu(0x0003);
527
528 footer->orig_size = be64_to_cpu(total_sectors * 512);
529 footer->size = be64_to_cpu(total_sectors * 512);
530
531 footer->cyls = be16_to_cpu(cyls);
532 footer->heads = heads;
533 footer->secs_per_cyl = secs_per_cyl;
534
535 footer->type = be32_to_cpu(VHD_DYNAMIC);
536
537 // TODO uuid is missing
538
539 footer->checksum = be32_to_cpu(vpc_checksum(buf, HEADER_SIZE));
540
541 // Write the footer (twice: at the beginning and at the end)
542 block_size = 0x200000;
543 num_bat_entries = (total_sectors + block_size / 512) / (block_size / 512);
544
545 if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE)
546 return -EIO;
547
548 if (lseek(fd, 1536 + ((num_bat_entries * 4 + 511) & ~511), SEEK_SET) < 0)
549 return -EIO;
550 if (write(fd, buf, HEADER_SIZE) != HEADER_SIZE)
551 return -EIO;
552
553 // Write the initial BAT
554 if (lseek(fd, 3 * 512, SEEK_SET) < 0)
555 return -EIO;
556
557 memset(buf, 0xFF, 512);
558 for (i = 0; i < (num_bat_entries * 4 + 511) / 512; i++)
559 if (write(fd, buf, 512) != 512)
560 return -EIO;
561
562
563 // Prepare the Dynamic Disk Header
564 memset(buf, 0, 1024);
565
5ec4d682 566 memcpy(dyndisk_header->magic, "cxsparse", 8);
57c7d9e5
AL
567
568 dyndisk_header->data_offset = be64_to_cpu(0xFFFFFFFF);
569 dyndisk_header->table_offset = be64_to_cpu(3 * 512);
570 dyndisk_header->version = be32_to_cpu(0x00010000);
571 dyndisk_header->block_size = be32_to_cpu(block_size);
572 dyndisk_header->max_table_entries = be32_to_cpu(num_bat_entries);
573
574 dyndisk_header->checksum = be32_to_cpu(vpc_checksum(buf, 1024));
575
576 // Write the header
577 if (lseek(fd, 512, SEEK_SET) < 0)
578 return -EIO;
579 if (write(fd, buf, 1024) != 1024)
580 return -EIO;
581
582 close(fd);
583 return 0;
584}
585
6a0f9e82
FB
586static void vpc_close(BlockDriverState *bs)
587{
588 BDRVVPCState *s = bs->opaque;
589 qemu_free(s->pagetable);
590#ifdef CACHE
591 qemu_free(s->pageentry_u8);
592#endif
b71d1c2e 593 bdrv_delete(s->hd);
6a0f9e82
FB
594}
595
0e7e1989 596static QEMUOptionParameter vpc_create_options[] = {
db08adf5
KW
597 {
598 .name = BLOCK_OPT_SIZE,
599 .type = OPT_SIZE,
600 .help = "Virtual disk size"
601 },
0e7e1989
KW
602 { NULL }
603};
604
5efa9d5a 605static BlockDriver bdrv_vpc = {
e60f469c
AJ
606 .format_name = "vpc",
607 .instance_size = sizeof(BDRVVPCState),
608 .bdrv_probe = vpc_probe,
609 .bdrv_open = vpc_open,
610 .bdrv_read = vpc_read,
611 .bdrv_write = vpc_write,
612 .bdrv_close = vpc_close,
613 .bdrv_create = vpc_create,
0e7e1989
KW
614
615 .create_options = vpc_create_options,
6a0f9e82 616};
5efa9d5a
AL
617
618static void bdrv_vpc_init(void)
619{
620 bdrv_register(&bdrv_vpc);
621}
622
623block_init(bdrv_vpc_init);