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1
/*
2
 *  Copyright (C) 2005  Anthony Liguori <anthony@codemonkey.ws>
3
 *
4
 *  Network Block Device
5
 *
6
 *  This program is free software; you can redistribute it and/or modify
7
 *  it under the terms of the GNU General Public License as published by
8
 *  the Free Software Foundation; under version 2 of the License.
9
 *
10
 *  This program is distributed in the hope that it will be useful,
11
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
12
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
13
 *  GNU General Public License for more details.
14
 *
15
 *  You should have received a copy of the GNU General Public License
16
 *  along with this program; if not, see <http://www.gnu.org/licenses/>.
17
 */
18

    
19
#include "qemu-common.h"
20
#include "block/block.h"
21
#include "block/nbd.h"
22
#include "qemu/main-loop.h"
23

    
24
#include <stdarg.h>
25
#include <stdio.h>
26
#include <getopt.h>
27
#include <err.h>
28
#include <sys/types.h>
29
#include <sys/socket.h>
30
#include <netinet/in.h>
31
#include <netinet/tcp.h>
32
#include <arpa/inet.h>
33
#include <signal.h>
34
#include <libgen.h>
35
#include <pthread.h>
36

    
37
#define SOCKET_PATH          "/var/lock/qemu-nbd-%s"
38
#define QEMU_NBD_OPT_CACHE   1
39
#define QEMU_NBD_OPT_AIO     2
40
#define QEMU_NBD_OPT_DISCARD 3
41

    
42
static NBDExport *exp;
43
static int verbose;
44
static char *srcpath;
45
static char *sockpath;
46
static int persistent = 0;
47
static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
48
static int shared = 1;
49
static int nb_fds;
50

    
51
static void usage(const char *name)
52
{
53
    (printf) (
54
"Usage: %s [OPTIONS] FILE\n"
55
"QEMU Disk Network Block Device Server\n"
56
"\n"
57
"  -h, --help           display this help and exit\n"
58
"  -V, --version        output version information and exit\n"
59
"\n"
60
"Connection properties:\n"
61
"  -p, --port=PORT      port to listen on (default `%d')\n"
62
"  -b, --bind=IFACE     interface to bind to (default `0.0.0.0')\n"
63
"  -k, --socket=PATH    path to the unix socket\n"
64
"                       (default '"SOCKET_PATH"')\n"
65
"  -e, --shared=NUM     device can be shared by NUM clients (default '1')\n"
66
"  -t, --persistent     don't exit on the last connection\n"
67
"  -v, --verbose        display extra debugging information\n"
68
"\n"
69
"Exposing part of the image:\n"
70
"  -o, --offset=OFFSET  offset into the image\n"
71
"  -P, --partition=NUM  only expose partition NUM\n"
72
"\n"
73
#ifdef __linux__
74
"Kernel NBD client support:\n"
75
"  -c, --connect=DEV    connect FILE to the local NBD device DEV\n"
76
"  -d, --disconnect     disconnect the specified device\n"
77
"\n"
78
#endif
79
"\n"
80
"Block device options:\n"
81
"  -r, --read-only      export read-only\n"
82
"  -s, --snapshot       use snapshot file\n"
83
"  -n, --nocache        disable host cache\n"
84
"      --cache=MODE     set cache mode (none, writeback, ...)\n"
85
#ifdef CONFIG_LINUX_AIO
86
"      --aio=MODE       set AIO mode (native or threads)\n"
87
#endif
88
"\n"
89
"Report bugs to <qemu-devel@nongnu.org>\n"
90
    , name, NBD_DEFAULT_PORT, "DEVICE");
91
}
92

    
93
static void version(const char *name)
94
{
95
    printf(
96
"%s version 0.0.1\n"
97
"Written by Anthony Liguori.\n"
98
"\n"
99
"Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n"
100
"This is free software; see the source for copying conditions.  There is NO\n"
101
"warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
102
    , name);
103
}
104

    
105
struct partition_record
106
{
107
    uint8_t bootable;
108
    uint8_t start_head;
109
    uint32_t start_cylinder;
110
    uint8_t start_sector;
111
    uint8_t system;
112
    uint8_t end_head;
113
    uint8_t end_cylinder;
114
    uint8_t end_sector;
115
    uint32_t start_sector_abs;
116
    uint32_t nb_sectors_abs;
117
};
118

    
119
static void read_partition(uint8_t *p, struct partition_record *r)
120
{
121
    r->bootable = p[0];
122
    r->start_head = p[1];
123
    r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300);
124
    r->start_sector = p[2] & 0x3f;
125
    r->system = p[4];
126
    r->end_head = p[5];
127
    r->end_cylinder = p[7] | ((p[6] << 2) & 0x300);
128
    r->end_sector = p[6] & 0x3f;
129
    r->start_sector_abs = p[8] | p[9] << 8 | p[10] << 16 | p[11] << 24;
130
    r->nb_sectors_abs = p[12] | p[13] << 8 | p[14] << 16 | p[15] << 24;
131
}
132

    
133
static int find_partition(BlockDriverState *bs, int partition,
134
                          off_t *offset, off_t *size)
135
{
136
    struct partition_record mbr[4];
137
    uint8_t data[512];
138
    int i;
139
    int ext_partnum = 4;
140
    int ret;
141

    
142
    if ((ret = bdrv_read(bs, 0, data, 1)) < 0) {
143
        errno = -ret;
144
        err(EXIT_FAILURE, "error while reading");
145
    }
146

    
147
    if (data[510] != 0x55 || data[511] != 0xaa) {
148
        return -EINVAL;
149
    }
150

    
151
    for (i = 0; i < 4; i++) {
152
        read_partition(&data[446 + 16 * i], &mbr[i]);
153

    
154
        if (!mbr[i].nb_sectors_abs)
155
            continue;
156

    
157
        if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
158
            struct partition_record ext[4];
159
            uint8_t data1[512];
160
            int j;
161

    
162
            if ((ret = bdrv_read(bs, mbr[i].start_sector_abs, data1, 1)) < 0) {
163
                errno = -ret;
164
                err(EXIT_FAILURE, "error while reading");
165
            }
166

    
167
            for (j = 0; j < 4; j++) {
168
                read_partition(&data1[446 + 16 * j], &ext[j]);
169
                if (!ext[j].nb_sectors_abs)
170
                    continue;
171

    
172
                if ((ext_partnum + j + 1) == partition) {
173
                    *offset = (uint64_t)ext[j].start_sector_abs << 9;
174
                    *size = (uint64_t)ext[j].nb_sectors_abs << 9;
175
                    return 0;
176
                }
177
            }
178
            ext_partnum += 4;
179
        } else if ((i + 1) == partition) {
180
            *offset = (uint64_t)mbr[i].start_sector_abs << 9;
181
            *size = (uint64_t)mbr[i].nb_sectors_abs << 9;
182
            return 0;
183
        }
184
    }
185

    
186
    return -ENOENT;
187
}
188

    
189
static void termsig_handler(int signum)
190
{
191
    state = TERMINATE;
192
    qemu_notify_event();
193
}
194

    
195
static void *show_parts(void *arg)
196
{
197
    char *device = arg;
198
    int nbd;
199

    
200
    /* linux just needs an open() to trigger
201
     * the partition table update
202
     * but remember to load the module with max_part != 0 :
203
     *     modprobe nbd max_part=63
204
     */
205
    nbd = open(device, O_RDWR);
206
    if (nbd >= 0) {
207
        close(nbd);
208
    }
209
    return NULL;
210
}
211

    
212
static void *nbd_client_thread(void *arg)
213
{
214
    char *device = arg;
215
    off_t size;
216
    size_t blocksize;
217
    uint32_t nbdflags;
218
    int fd, sock;
219
    int ret;
220
    pthread_t show_parts_thread;
221

    
222
    sock = unix_socket_outgoing(sockpath);
223
    if (sock < 0) {
224
        goto out;
225
    }
226

    
227
    ret = nbd_receive_negotiate(sock, NULL, &nbdflags,
228
                                &size, &blocksize);
229
    if (ret < 0) {
230
        goto out;
231
    }
232

    
233
    fd = open(device, O_RDWR);
234
    if (fd < 0) {
235
        /* Linux-only, we can use %m in printf.  */
236
        fprintf(stderr, "Failed to open %s: %m", device);
237
        goto out;
238
    }
239

    
240
    ret = nbd_init(fd, sock, nbdflags, size, blocksize);
241
    if (ret < 0) {
242
        goto out;
243
    }
244

    
245
    /* update partition table */
246
    pthread_create(&show_parts_thread, NULL, show_parts, device);
247

    
248
    if (verbose) {
249
        fprintf(stderr, "NBD device %s is now connected to %s\n",
250
                device, srcpath);
251
    } else {
252
        /* Close stderr so that the qemu-nbd process exits.  */
253
        dup2(STDOUT_FILENO, STDERR_FILENO);
254
    }
255

    
256
    ret = nbd_client(fd);
257
    if (ret) {
258
        goto out;
259
    }
260
    close(fd);
261
    kill(getpid(), SIGTERM);
262
    return (void *) EXIT_SUCCESS;
263

    
264
out:
265
    kill(getpid(), SIGTERM);
266
    return (void *) EXIT_FAILURE;
267
}
268

    
269
static int nbd_can_accept(void *opaque)
270
{
271
    return nb_fds < shared;
272
}
273

    
274
static void nbd_export_closed(NBDExport *exp)
275
{
276
    assert(state == TERMINATING);
277
    state = TERMINATED;
278
}
279

    
280
static void nbd_client_closed(NBDClient *client)
281
{
282
    nb_fds--;
283
    if (nb_fds == 0 && !persistent && state == RUNNING) {
284
        state = TERMINATE;
285
    }
286
    qemu_notify_event();
287
    nbd_client_put(client);
288
}
289

    
290
static void nbd_accept(void *opaque)
291
{
292
    int server_fd = (uintptr_t) opaque;
293
    struct sockaddr_in addr;
294
    socklen_t addr_len = sizeof(addr);
295

    
296
    int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
297
    if (state >= TERMINATE) {
298
        close(fd);
299
        return;
300
    }
301

    
302
    if (fd >= 0 && nbd_client_new(exp, fd, nbd_client_closed)) {
303
        nb_fds++;
304
    }
305
}
306

    
307
int main(int argc, char **argv)
308
{
309
    BlockDriverState *bs;
310
    BlockDriver *drv;
311
    off_t dev_offset = 0;
312
    uint32_t nbdflags = 0;
313
    bool disconnect = false;
314
    const char *bindto = "0.0.0.0";
315
    char *device = NULL;
316
    int port = NBD_DEFAULT_PORT;
317
    off_t fd_size;
318
    const char *sopt = "hVb:o:p:rsnP:c:dvk:e:f:t";
319
    struct option lopt[] = {
320
        { "help", 0, NULL, 'h' },
321
        { "version", 0, NULL, 'V' },
322
        { "bind", 1, NULL, 'b' },
323
        { "port", 1, NULL, 'p' },
324
        { "socket", 1, NULL, 'k' },
325
        { "offset", 1, NULL, 'o' },
326
        { "read-only", 0, NULL, 'r' },
327
        { "partition", 1, NULL, 'P' },
328
        { "connect", 1, NULL, 'c' },
329
        { "disconnect", 0, NULL, 'd' },
330
        { "snapshot", 0, NULL, 's' },
331
        { "nocache", 0, NULL, 'n' },
332
        { "cache", 1, NULL, QEMU_NBD_OPT_CACHE },
333
#ifdef CONFIG_LINUX_AIO
334
        { "aio", 1, NULL, QEMU_NBD_OPT_AIO },
335
#endif
336
        { "discard", 1, NULL, QEMU_NBD_OPT_DISCARD },
337
        { "shared", 1, NULL, 'e' },
338
        { "format", 1, NULL, 'f' },
339
        { "persistent", 0, NULL, 't' },
340
        { "verbose", 0, NULL, 'v' },
341
        { NULL, 0, NULL, 0 }
342
    };
343
    int ch;
344
    int opt_ind = 0;
345
    int li;
346
    char *end;
347
    int flags = BDRV_O_RDWR;
348
    int partition = -1;
349
    int ret;
350
    int fd;
351
    bool seen_cache = false;
352
    bool seen_discard = false;
353
#ifdef CONFIG_LINUX_AIO
354
    bool seen_aio = false;
355
#endif
356
    pthread_t client_thread;
357
    const char *fmt = NULL;
358
    Error *local_err = NULL;
359

    
360
    /* The client thread uses SIGTERM to interrupt the server.  A signal
361
     * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
362
     */
363
    struct sigaction sa_sigterm;
364
    memset(&sa_sigterm, 0, sizeof(sa_sigterm));
365
    sa_sigterm.sa_handler = termsig_handler;
366
    sigaction(SIGTERM, &sa_sigterm, NULL);
367

    
368
    while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
369
        switch (ch) {
370
        case 's':
371
            flags |= BDRV_O_SNAPSHOT;
372
            break;
373
        case 'n':
374
            optarg = (char *) "none";
375
            /* fallthrough */
376
        case QEMU_NBD_OPT_CACHE:
377
            if (seen_cache) {
378
                errx(EXIT_FAILURE, "-n and --cache can only be specified once");
379
            }
380
            seen_cache = true;
381
            if (bdrv_parse_cache_flags(optarg, &flags) == -1) {
382
                errx(EXIT_FAILURE, "Invalid cache mode `%s'", optarg);
383
            }
384
            break;
385
#ifdef CONFIG_LINUX_AIO
386
        case QEMU_NBD_OPT_AIO:
387
            if (seen_aio) {
388
                errx(EXIT_FAILURE, "--aio can only be specified once");
389
            }
390
            seen_aio = true;
391
            if (!strcmp(optarg, "native")) {
392
                flags |= BDRV_O_NATIVE_AIO;
393
            } else if (!strcmp(optarg, "threads")) {
394
                /* this is the default */
395
            } else {
396
               errx(EXIT_FAILURE, "invalid aio mode `%s'", optarg);
397
            }
398
            break;
399
#endif
400
        case QEMU_NBD_OPT_DISCARD:
401
            if (seen_discard) {
402
                errx(EXIT_FAILURE, "--discard can only be specified once");
403
            }
404
            seen_discard = true;
405
            if (bdrv_parse_discard_flags(optarg, &flags) == -1) {
406
                errx(EXIT_FAILURE, "Invalid discard mode `%s'", optarg);
407
            }
408
            break;
409
        case 'b':
410
            bindto = optarg;
411
            break;
412
        case 'p':
413
            li = strtol(optarg, &end, 0);
414
            if (*end) {
415
                errx(EXIT_FAILURE, "Invalid port `%s'", optarg);
416
            }
417
            if (li < 1 || li > 65535) {
418
                errx(EXIT_FAILURE, "Port out of range `%s'", optarg);
419
            }
420
            port = (uint16_t)li;
421
            break;
422
        case 'o':
423
                dev_offset = strtoll (optarg, &end, 0);
424
            if (*end) {
425
                errx(EXIT_FAILURE, "Invalid offset `%s'", optarg);
426
            }
427
            if (dev_offset < 0) {
428
                errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg);
429
            }
430
            break;
431
        case 'r':
432
            nbdflags |= NBD_FLAG_READ_ONLY;
433
            flags &= ~BDRV_O_RDWR;
434
            break;
435
        case 'P':
436
            partition = strtol(optarg, &end, 0);
437
            if (*end)
438
                errx(EXIT_FAILURE, "Invalid partition `%s'", optarg);
439
            if (partition < 1 || partition > 8)
440
                errx(EXIT_FAILURE, "Invalid partition %d", partition);
441
            break;
442
        case 'k':
443
            sockpath = optarg;
444
            if (sockpath[0] != '/')
445
                errx(EXIT_FAILURE, "socket path must be absolute\n");
446
            break;
447
        case 'd':
448
            disconnect = true;
449
            break;
450
        case 'c':
451
            device = optarg;
452
            break;
453
        case 'e':
454
            shared = strtol(optarg, &end, 0);
455
            if (*end) {
456
                errx(EXIT_FAILURE, "Invalid shared device number '%s'", optarg);
457
            }
458
            if (shared < 1) {
459
                errx(EXIT_FAILURE, "Shared device number must be greater than 0\n");
460
            }
461
            break;
462
        case 'f':
463
            fmt = optarg;
464
            break;
465
        case 't':
466
            persistent = 1;
467
            break;
468
        case 'v':
469
            verbose = 1;
470
            break;
471
        case 'V':
472
            version(argv[0]);
473
            exit(0);
474
            break;
475
        case 'h':
476
            usage(argv[0]);
477
            exit(0);
478
            break;
479
        case '?':
480
            errx(EXIT_FAILURE, "Try `%s --help' for more information.",
481
                 argv[0]);
482
        }
483
    }
484

    
485
    if ((argc - optind) != 1) {
486
        errx(EXIT_FAILURE, "Invalid number of argument.\n"
487
             "Try `%s --help' for more information.",
488
             argv[0]);
489
    }
490

    
491
    if (disconnect) {
492
        fd = open(argv[optind], O_RDWR);
493
        if (fd < 0) {
494
            err(EXIT_FAILURE, "Cannot open %s", argv[optind]);
495
        }
496
        nbd_disconnect(fd);
497

    
498
        close(fd);
499

    
500
        printf("%s disconnected\n", argv[optind]);
501

    
502
        return 0;
503
    }
504

    
505
    if (device && !verbose) {
506
        int stderr_fd[2];
507
        pid_t pid;
508
        int ret;
509

    
510
        if (qemu_pipe(stderr_fd) < 0) {
511
            err(EXIT_FAILURE, "Error setting up communication pipe");
512
        }
513

    
514
        /* Now daemonize, but keep a communication channel open to
515
         * print errors and exit with the proper status code.
516
         */
517
        pid = fork();
518
        if (pid == 0) {
519
            close(stderr_fd[0]);
520
            ret = qemu_daemon(1, 0);
521

    
522
            /* Temporarily redirect stderr to the parent's pipe...  */
523
            dup2(stderr_fd[1], STDERR_FILENO);
524
            if (ret < 0) {
525
                err(EXIT_FAILURE, "Failed to daemonize");
526
            }
527

    
528
            /* ... close the descriptor we inherited and go on.  */
529
            close(stderr_fd[1]);
530
        } else {
531
            bool errors = false;
532
            char *buf;
533

    
534
            /* In the parent.  Print error messages from the child until
535
             * it closes the pipe.
536
             */
537
            close(stderr_fd[1]);
538
            buf = g_malloc(1024);
539
            while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
540
                errors = true;
541
                ret = qemu_write_full(STDERR_FILENO, buf, ret);
542
                if (ret < 0) {
543
                    exit(EXIT_FAILURE);
544
                }
545
            }
546
            if (ret < 0) {
547
                err(EXIT_FAILURE, "Cannot read from daemon");
548
            }
549

    
550
            /* Usually the daemon should not print any message.
551
             * Exit with zero status in that case.
552
             */
553
            exit(errors);
554
        }
555
    }
556

    
557
    if (device != NULL && sockpath == NULL) {
558
        sockpath = g_malloc(128);
559
        snprintf(sockpath, 128, SOCKET_PATH, basename(device));
560
    }
561

    
562
    qemu_init_main_loop();
563
    bdrv_init();
564
    atexit(bdrv_close_all);
565

    
566
    if (fmt) {
567
        drv = bdrv_find_format(fmt);
568
        if (!drv) {
569
            errx(EXIT_FAILURE, "Unknown file format '%s'", fmt);
570
        }
571
    } else {
572
        drv = NULL;
573
    }
574

    
575
    bs = bdrv_new("hda");
576
    srcpath = argv[optind];
577
    ret = bdrv_open(bs, srcpath, NULL, flags, drv, &local_err);
578
    if (ret < 0) {
579
        errno = -ret;
580
        err(EXIT_FAILURE, "Failed to bdrv_open '%s': %s", argv[optind],
581
            error_get_pretty(local_err));
582
    }
583

    
584
    fd_size = bdrv_getlength(bs);
585

    
586
    if (partition != -1) {
587
        ret = find_partition(bs, partition, &dev_offset, &fd_size);
588
        if (ret < 0) {
589
            errno = -ret;
590
            err(EXIT_FAILURE, "Could not find partition %d", partition);
591
        }
592
    }
593

    
594
    exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed);
595

    
596
    if (sockpath) {
597
        fd = unix_socket_incoming(sockpath);
598
    } else {
599
        fd = tcp_socket_incoming(bindto, port);
600
    }
601

    
602
    if (fd < 0) {
603
        return 1;
604
    }
605

    
606
    if (device) {
607
        int ret;
608

    
609
        ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
610
        if (ret != 0) {
611
            errx(EXIT_FAILURE, "Failed to create client thread: %s",
612
                 strerror(ret));
613
        }
614
    } else {
615
        /* Shut up GCC warnings.  */
616
        memset(&client_thread, 0, sizeof(client_thread));
617
    }
618

    
619
    qemu_set_fd_handler2(fd, nbd_can_accept, nbd_accept, NULL,
620
                         (void *)(uintptr_t)fd);
621

    
622
    /* now when the initialization is (almost) complete, chdir("/")
623
     * to free any busy filesystems */
624
    if (chdir("/") < 0) {
625
        err(EXIT_FAILURE, "Could not chdir to root directory");
626
    }
627

    
628
    state = RUNNING;
629
    do {
630
        main_loop_wait(false);
631
        if (state == TERMINATE) {
632
            state = TERMINATING;
633
            nbd_export_close(exp);
634
            nbd_export_put(exp);
635
            exp = NULL;
636
        }
637
    } while (state != TERMINATED);
638

    
639
    bdrv_close(bs);
640
    if (sockpath) {
641
        unlink(sockpath);
642
    }
643

    
644
    if (device) {
645
        void *ret;
646
        pthread_join(client_thread, &ret);
647
        exit(ret != NULL);
648
    } else {
649
        exit(EXIT_SUCCESS);
650
    }
651
}