root / qemu-nbd.c @ fc19f8a0
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/*
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* Copyright (C) 2005 Anthony Liguori <anthony@codemonkey.ws>
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*
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* Network Block Device
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; under version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, see <http://www.gnu.org/licenses/>.
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*/
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#include "qemu-common.h" |
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#include "block_int.h" |
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#include "nbd.h" |
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|
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#include <stdarg.h> |
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#include <stdio.h> |
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#include <getopt.h> |
26 |
#include <err.h> |
27 |
#include <sys/types.h> |
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#include <sys/socket.h> |
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#include <netinet/in.h> |
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#include <netinet/tcp.h> |
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#include <arpa/inet.h> |
32 |
#include <signal.h> |
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#include <libgen.h> |
34 |
#include <pthread.h> |
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|
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#define SOCKET_PATH "/var/lock/qemu-nbd-%s" |
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|
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static NBDExport *exp;
|
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static int verbose; |
40 |
static char *srcpath; |
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static char *sockpath; |
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static bool sigterm_reported; |
43 |
static bool nbd_started; |
44 |
static int shared = 1; |
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static int nb_fds; |
46 |
|
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static void usage(const char *name) |
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{ |
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printf( |
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"Usage: %s [OPTIONS] FILE\n"
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"QEMU Disk Network Block Device Server\n"
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"\n"
|
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" -p, --port=PORT port to listen on (default `%d')\n"
|
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" -o, --offset=OFFSET offset into the image\n"
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" -b, --bind=IFACE interface to bind to (default `0.0.0.0')\n"
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" -k, --socket=PATH path to the unix socket\n"
|
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" (default '"SOCKET_PATH"')\n" |
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" -r, --read-only export read-only\n"
|
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" -P, --partition=NUM only expose partition NUM\n"
|
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" -s, --snapshot use snapshot file\n"
|
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" -n, --nocache disable host cache\n"
|
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" -c, --connect=DEV connect FILE to the local NBD device DEV\n"
|
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" -d, --disconnect disconnect the specified device\n"
|
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" -e, --shared=NUM device can be shared by NUM clients (default '1')\n"
|
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" -t, --persistent don't exit on the last connection\n"
|
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" -v, --verbose display extra debugging information\n"
|
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" -h, --help display this help and exit\n"
|
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" -V, --version output version information and exit\n"
|
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"\n"
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"Report bugs to <anthony@codemonkey.ws>\n"
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, name, NBD_DEFAULT_PORT, "DEVICE");
|
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} |
73 |
|
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static void version(const char *name) |
75 |
{ |
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printf( |
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"%s version 0.0.1\n"
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"Written by Anthony Liguori.\n"
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"\n"
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"Copyright (C) 2006 Anthony Liguori <anthony@codemonkey.ws>.\n"
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"This is free software; see the source for copying conditions. There is NO\n"
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"warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
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, name); |
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} |
85 |
|
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struct partition_record
|
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{ |
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uint8_t bootable; |
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uint8_t start_head; |
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uint32_t start_cylinder; |
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uint8_t start_sector; |
92 |
uint8_t system; |
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uint8_t end_head; |
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uint8_t end_cylinder; |
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uint8_t end_sector; |
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uint32_t start_sector_abs; |
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uint32_t nb_sectors_abs; |
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}; |
99 |
|
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static void read_partition(uint8_t *p, struct partition_record *r) |
101 |
{ |
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r->bootable = p[0];
|
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r->start_head = p[1];
|
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r->start_cylinder = p[3] | ((p[2] << 2) & 0x0300); |
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r->start_sector = p[2] & 0x3f; |
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r->system = p[4];
|
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r->end_head = p[5];
|
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r->end_cylinder = p[7] | ((p[6] << 2) & 0x300); |
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r->end_sector = p[6] & 0x3f; |
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r->start_sector_abs = p[8] | p[9] << 8 | p[10] << 16 | p[11] << 24; |
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r->nb_sectors_abs = p[12] | p[13] << 8 | p[14] << 16 | p[15] << 24; |
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} |
113 |
|
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static int find_partition(BlockDriverState *bs, int partition, |
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off_t *offset, off_t *size) |
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{ |
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struct partition_record mbr[4]; |
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uint8_t data[512];
|
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int i;
|
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int ext_partnum = 4; |
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int ret;
|
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|
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if ((ret = bdrv_read(bs, 0, data, 1)) < 0) { |
124 |
errno = -ret; |
125 |
err(EXIT_FAILURE, "error while reading");
|
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} |
127 |
|
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if (data[510] != 0x55 || data[511] != 0xaa) { |
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errno = -EINVAL; |
130 |
return -1; |
131 |
} |
132 |
|
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for (i = 0; i < 4; i++) { |
134 |
read_partition(&data[446 + 16 * i], &mbr[i]); |
135 |
|
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if (!mbr[i].nb_sectors_abs)
|
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continue;
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138 |
|
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if (mbr[i].system == 0xF || mbr[i].system == 0x5) { |
140 |
struct partition_record ext[4]; |
141 |
uint8_t data1[512];
|
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int j;
|
143 |
|
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if ((ret = bdrv_read(bs, mbr[i].start_sector_abs, data1, 1)) < 0) { |
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errno = -ret; |
146 |
err(EXIT_FAILURE, "error while reading");
|
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} |
148 |
|
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for (j = 0; j < 4; j++) { |
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read_partition(&data1[446 + 16 * j], &ext[j]); |
151 |
if (!ext[j].nb_sectors_abs)
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continue;
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153 |
|
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if ((ext_partnum + j + 1) == partition) { |
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*offset = (uint64_t)ext[j].start_sector_abs << 9;
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*size = (uint64_t)ext[j].nb_sectors_abs << 9;
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return 0; |
158 |
} |
159 |
} |
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ext_partnum += 4;
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} else if ((i + 1) == partition) { |
162 |
*offset = (uint64_t)mbr[i].start_sector_abs << 9;
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*size = (uint64_t)mbr[i].nb_sectors_abs << 9;
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return 0; |
165 |
} |
166 |
} |
167 |
|
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errno = -ENOENT; |
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return -1; |
170 |
} |
171 |
|
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static void termsig_handler(int signum) |
173 |
{ |
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sigterm_reported = true;
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qemu_notify_event(); |
176 |
} |
177 |
|
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static void *show_parts(void *arg) |
179 |
{ |
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char *device = arg;
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int nbd;
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|
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/* linux just needs an open() to trigger
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* the partition table update
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* but remember to load the module with max_part != 0 :
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* modprobe nbd max_part=63
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*/
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nbd = open(device, O_RDWR); |
189 |
if (nbd >= 0) { |
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close(nbd); |
191 |
} |
192 |
return NULL; |
193 |
} |
194 |
|
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static void *nbd_client_thread(void *arg) |
196 |
{ |
197 |
char *device = arg;
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off_t size; |
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size_t blocksize; |
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uint32_t nbdflags; |
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int fd, sock;
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int ret;
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pthread_t show_parts_thread; |
204 |
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sock = unix_socket_outgoing(sockpath); |
206 |
if (sock < 0) { |
207 |
goto out;
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} |
209 |
|
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ret = nbd_receive_negotiate(sock, NULL, &nbdflags,
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&size, &blocksize); |
212 |
if (ret < 0) { |
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goto out;
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} |
215 |
|
216 |
fd = open(device, O_RDWR); |
217 |
if (fd < 0) { |
218 |
/* Linux-only, we can use %m in printf. */
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fprintf(stderr, "Failed to open %s: %m", device);
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goto out;
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} |
222 |
|
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ret = nbd_init(fd, sock, nbdflags, size, blocksize); |
224 |
if (ret < 0) { |
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goto out;
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} |
227 |
|
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/* update partition table */
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pthread_create(&show_parts_thread, NULL, show_parts, device);
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if (verbose) {
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fprintf(stderr, "NBD device %s is now connected to %s\n",
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device, srcpath); |
234 |
} else {
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/* Close stderr so that the qemu-nbd process exits. */
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dup2(STDOUT_FILENO, STDERR_FILENO); |
237 |
} |
238 |
|
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ret = nbd_client(fd); |
240 |
if (ret) {
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goto out;
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} |
243 |
close(fd); |
244 |
kill(getpid(), SIGTERM); |
245 |
return (void *) EXIT_SUCCESS; |
246 |
|
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out:
|
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kill(getpid(), SIGTERM); |
249 |
return (void *) EXIT_FAILURE; |
250 |
} |
251 |
|
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static int nbd_can_accept(void *opaque) |
253 |
{ |
254 |
return nb_fds < shared;
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} |
256 |
|
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static void nbd_client_closed(NBDClient *client) |
258 |
{ |
259 |
nb_fds--; |
260 |
qemu_notify_event(); |
261 |
} |
262 |
|
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static void nbd_accept(void *opaque) |
264 |
{ |
265 |
int server_fd = (uintptr_t) opaque;
|
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struct sockaddr_in addr;
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socklen_t addr_len = sizeof(addr);
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|
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int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len); |
270 |
nbd_started = true;
|
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if (fd >= 0 && nbd_client_new(exp, fd, nbd_client_closed)) { |
272 |
nb_fds++; |
273 |
} |
274 |
} |
275 |
|
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int main(int argc, char **argv) |
277 |
{ |
278 |
BlockDriverState *bs; |
279 |
off_t dev_offset = 0;
|
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uint32_t nbdflags = 0;
|
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bool disconnect = false; |
282 |
const char *bindto = "0.0.0.0"; |
283 |
char *device = NULL; |
284 |
int port = NBD_DEFAULT_PORT;
|
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off_t fd_size; |
286 |
const char *sopt = "hVb:o:p:rsnP:c:dvk:e:t"; |
287 |
struct option lopt[] = {
|
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{ "help", 0, NULL, 'h' }, |
289 |
{ "version", 0, NULL, 'V' }, |
290 |
{ "bind", 1, NULL, 'b' }, |
291 |
{ "port", 1, NULL, 'p' }, |
292 |
{ "socket", 1, NULL, 'k' }, |
293 |
{ "offset", 1, NULL, 'o' }, |
294 |
{ "read-only", 0, NULL, 'r' }, |
295 |
{ "partition", 1, NULL, 'P' }, |
296 |
{ "connect", 1, NULL, 'c' }, |
297 |
{ "disconnect", 0, NULL, 'd' }, |
298 |
{ "snapshot", 0, NULL, 's' }, |
299 |
{ "nocache", 0, NULL, 'n' }, |
300 |
{ "shared", 1, NULL, 'e' }, |
301 |
{ "persistent", 0, NULL, 't' }, |
302 |
{ "verbose", 0, NULL, 'v' }, |
303 |
{ NULL, 0, NULL, 0 } |
304 |
}; |
305 |
int ch;
|
306 |
int opt_ind = 0; |
307 |
int li;
|
308 |
char *end;
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309 |
int flags = BDRV_O_RDWR;
|
310 |
int partition = -1; |
311 |
int ret;
|
312 |
int fd;
|
313 |
int persistent = 0; |
314 |
pthread_t client_thread; |
315 |
|
316 |
/* The client thread uses SIGTERM to interrupt the server. A signal
|
317 |
* handler ensures that "qemu-nbd -v -c" exits with a nice status code.
|
318 |
*/
|
319 |
struct sigaction sa_sigterm;
|
320 |
memset(&sa_sigterm, 0, sizeof(sa_sigterm)); |
321 |
sa_sigterm.sa_handler = termsig_handler; |
322 |
sigaction(SIGTERM, &sa_sigterm, NULL);
|
323 |
|
324 |
while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) { |
325 |
switch (ch) {
|
326 |
case 's': |
327 |
flags |= BDRV_O_SNAPSHOT; |
328 |
break;
|
329 |
case 'n': |
330 |
flags |= BDRV_O_NOCACHE | BDRV_O_CACHE_WB; |
331 |
break;
|
332 |
case 'b': |
333 |
bindto = optarg; |
334 |
break;
|
335 |
case 'p': |
336 |
li = strtol(optarg, &end, 0);
|
337 |
if (*end) {
|
338 |
errx(EXIT_FAILURE, "Invalid port `%s'", optarg);
|
339 |
} |
340 |
if (li < 1 || li > 65535) { |
341 |
errx(EXIT_FAILURE, "Port out of range `%s'", optarg);
|
342 |
} |
343 |
port = (uint16_t)li; |
344 |
break;
|
345 |
case 'o': |
346 |
dev_offset = strtoll (optarg, &end, 0);
|
347 |
if (*end) {
|
348 |
errx(EXIT_FAILURE, "Invalid offset `%s'", optarg);
|
349 |
} |
350 |
if (dev_offset < 0) { |
351 |
errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg);
|
352 |
} |
353 |
break;
|
354 |
case 'r': |
355 |
nbdflags |= NBD_FLAG_READ_ONLY; |
356 |
flags &= ~BDRV_O_RDWR; |
357 |
break;
|
358 |
case 'P': |
359 |
partition = strtol(optarg, &end, 0);
|
360 |
if (*end)
|
361 |
errx(EXIT_FAILURE, "Invalid partition `%s'", optarg);
|
362 |
if (partition < 1 || partition > 8) |
363 |
errx(EXIT_FAILURE, "Invalid partition %d", partition);
|
364 |
break;
|
365 |
case 'k': |
366 |
sockpath = optarg; |
367 |
if (sockpath[0] != '/') |
368 |
errx(EXIT_FAILURE, "socket path must be absolute\n");
|
369 |
break;
|
370 |
case 'd': |
371 |
disconnect = true;
|
372 |
break;
|
373 |
case 'c': |
374 |
device = optarg; |
375 |
break;
|
376 |
case 'e': |
377 |
shared = strtol(optarg, &end, 0);
|
378 |
if (*end) {
|
379 |
errx(EXIT_FAILURE, "Invalid shared device number '%s'", optarg);
|
380 |
} |
381 |
if (shared < 1) { |
382 |
errx(EXIT_FAILURE, "Shared device number must be greater than 0\n");
|
383 |
} |
384 |
break;
|
385 |
case 't': |
386 |
persistent = 1;
|
387 |
break;
|
388 |
case 'v': |
389 |
verbose = 1;
|
390 |
break;
|
391 |
case 'V': |
392 |
version(argv[0]);
|
393 |
exit(0);
|
394 |
break;
|
395 |
case 'h': |
396 |
usage(argv[0]);
|
397 |
exit(0);
|
398 |
break;
|
399 |
case '?': |
400 |
errx(EXIT_FAILURE, "Try `%s --help' for more information.",
|
401 |
argv[0]);
|
402 |
} |
403 |
} |
404 |
|
405 |
if ((argc - optind) != 1) { |
406 |
errx(EXIT_FAILURE, "Invalid number of argument.\n"
|
407 |
"Try `%s --help' for more information.",
|
408 |
argv[0]);
|
409 |
} |
410 |
|
411 |
if (disconnect) {
|
412 |
fd = open(argv[optind], O_RDWR); |
413 |
if (fd < 0) { |
414 |
err(EXIT_FAILURE, "Cannot open %s", argv[optind]);
|
415 |
} |
416 |
nbd_disconnect(fd); |
417 |
|
418 |
close(fd); |
419 |
|
420 |
printf("%s disconnected\n", argv[optind]);
|
421 |
|
422 |
return 0; |
423 |
} |
424 |
|
425 |
if (device && !verbose) {
|
426 |
int stderr_fd[2]; |
427 |
pid_t pid; |
428 |
int ret;
|
429 |
|
430 |
if (qemu_pipe(stderr_fd) < 0) { |
431 |
err(EXIT_FAILURE, "Error setting up communication pipe");
|
432 |
} |
433 |
|
434 |
/* Now daemonize, but keep a communication channel open to
|
435 |
* print errors and exit with the proper status code.
|
436 |
*/
|
437 |
pid = fork(); |
438 |
if (pid == 0) { |
439 |
close(stderr_fd[0]);
|
440 |
ret = qemu_daemon(1, 0); |
441 |
|
442 |
/* Temporarily redirect stderr to the parent's pipe... */
|
443 |
dup2(stderr_fd[1], STDERR_FILENO);
|
444 |
if (ret < 0) { |
445 |
err(EXIT_FAILURE, "Failed to daemonize");
|
446 |
} |
447 |
|
448 |
/* ... close the descriptor we inherited and go on. */
|
449 |
close(stderr_fd[1]);
|
450 |
} else {
|
451 |
bool errors = false; |
452 |
char *buf;
|
453 |
|
454 |
/* In the parent. Print error messages from the child until
|
455 |
* it closes the pipe.
|
456 |
*/
|
457 |
close(stderr_fd[1]);
|
458 |
buf = g_malloc(1024);
|
459 |
while ((ret = read(stderr_fd[0], buf, 1024)) > 0) { |
460 |
errors = true;
|
461 |
ret = qemu_write_full(STDERR_FILENO, buf, ret); |
462 |
if (ret < 0) { |
463 |
exit(EXIT_FAILURE); |
464 |
} |
465 |
} |
466 |
if (ret < 0) { |
467 |
err(EXIT_FAILURE, "Cannot read from daemon");
|
468 |
} |
469 |
|
470 |
/* Usually the daemon should not print any message.
|
471 |
* Exit with zero status in that case.
|
472 |
*/
|
473 |
exit(errors); |
474 |
} |
475 |
} |
476 |
|
477 |
if (device != NULL && sockpath == NULL) { |
478 |
sockpath = g_malloc(128);
|
479 |
snprintf(sockpath, 128, SOCKET_PATH, basename(device));
|
480 |
} |
481 |
|
482 |
bdrv_init(); |
483 |
atexit(bdrv_close_all); |
484 |
|
485 |
bs = bdrv_new("hda");
|
486 |
srcpath = argv[optind]; |
487 |
if ((ret = bdrv_open(bs, srcpath, flags, NULL)) < 0) { |
488 |
errno = -ret; |
489 |
err(EXIT_FAILURE, "Failed to bdrv_open '%s'", argv[optind]);
|
490 |
} |
491 |
|
492 |
fd_size = bs->total_sectors * 512;
|
493 |
|
494 |
if (partition != -1 && |
495 |
find_partition(bs, partition, &dev_offset, &fd_size)) { |
496 |
err(EXIT_FAILURE, "Could not find partition %d", partition);
|
497 |
} |
498 |
|
499 |
exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags); |
500 |
|
501 |
if (sockpath) {
|
502 |
fd = unix_socket_incoming(sockpath); |
503 |
} else {
|
504 |
fd = tcp_socket_incoming(bindto, port); |
505 |
} |
506 |
|
507 |
if (fd < 0) { |
508 |
return 1; |
509 |
} |
510 |
|
511 |
if (device) {
|
512 |
int ret;
|
513 |
|
514 |
ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
|
515 |
if (ret != 0) { |
516 |
errx(EXIT_FAILURE, "Failed to create client thread: %s",
|
517 |
strerror(ret)); |
518 |
} |
519 |
} else {
|
520 |
/* Shut up GCC warnings. */
|
521 |
memset(&client_thread, 0, sizeof(client_thread)); |
522 |
} |
523 |
|
524 |
qemu_init_main_loop(); |
525 |
qemu_set_fd_handler2(fd, nbd_can_accept, nbd_accept, NULL,
|
526 |
(void *)(uintptr_t)fd);
|
527 |
|
528 |
/* now when the initialization is (almost) complete, chdir("/")
|
529 |
* to free any busy filesystems */
|
530 |
if (chdir("/") < 0) { |
531 |
err(EXIT_FAILURE, "Could not chdir to root directory");
|
532 |
} |
533 |
|
534 |
do {
|
535 |
main_loop_wait(false);
|
536 |
} while (!sigterm_reported && (persistent || !nbd_started || nb_fds > 0)); |
537 |
|
538 |
nbd_export_close(exp); |
539 |
if (sockpath) {
|
540 |
unlink(sockpath); |
541 |
} |
542 |
|
543 |
if (device) {
|
544 |
void *ret;
|
545 |
pthread_join(client_thread, &ret); |
546 |
exit(ret != NULL);
|
547 |
} else {
|
548 |
exit(EXIT_SUCCESS); |
549 |
} |
550 |
} |