mirror of
https://gitlab.com/qemu-project/qemu
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7860a380ac
Use a simple state machine with the following states: - RUNNING => accepting connections - TERMINATE => main loop must call nbd_export_close/put, and not accept connections anymore - TERMINATING => waiting for pending requests to finish - TERMINATED => the NBDExport has been closed Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
620 lines
17 KiB
C
620 lines
17 KiB
C
/*
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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.h"
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#include "nbd.h"
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#include <stdarg.h>
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#include <stdio.h>
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#include <getopt.h>
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#include <err.h>
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#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>
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#include <signal.h>
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#include <libgen.h>
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#include <pthread.h>
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#define SOCKET_PATH "/var/lock/qemu-nbd-%s"
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#define QEMU_NBD_OPT_CACHE 1
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#define QEMU_NBD_OPT_AIO 2
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static NBDExport *exp;
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static int verbose;
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static char *srcpath;
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static char *sockpath;
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static int persistent = 0;
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static enum { RUNNING, TERMINATE, TERMINATING, TERMINATED } state;
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static int shared = 1;
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static int nb_fds;
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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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" -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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"Connection properties:\n"
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" -p, --port=PORT port to listen on (default `%d')\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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" -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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"\n"
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"Exposing part of the image:\n"
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" -o, --offset=OFFSET offset into the image\n"
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" -P, --partition=NUM only expose partition NUM\n"
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"\n"
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#ifdef __linux__
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"Kernel NBD client support:\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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"\n"
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#endif
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"\n"
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"Block device options:\n"
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" -r, --read-only export read-only\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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" --cache=MODE set cache mode (none, writeback, ...)\n"
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#ifdef CONFIG_LINUX_AIO
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" --aio=MODE set AIO mode (native or threads)\n"
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#endif
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"\n"
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"Report bugs to <qemu-devel@nongnu.org>\n"
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, name, NBD_DEFAULT_PORT, "DEVICE");
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}
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static void version(const char *name)
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{
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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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}
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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;
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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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};
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static void read_partition(uint8_t *p, struct partition_record *r)
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{
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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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}
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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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if ((ret = bdrv_read(bs, 0, data, 1)) < 0) {
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errno = -ret;
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err(EXIT_FAILURE, "error while reading");
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}
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if (data[510] != 0x55 || data[511] != 0xaa) {
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return -EINVAL;
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}
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for (i = 0; i < 4; i++) {
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read_partition(&data[446 + 16 * i], &mbr[i]);
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if (!mbr[i].nb_sectors_abs)
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continue;
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if (mbr[i].system == 0xF || mbr[i].system == 0x5) {
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struct partition_record ext[4];
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uint8_t data1[512];
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int j;
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if ((ret = bdrv_read(bs, mbr[i].start_sector_abs, data1, 1)) < 0) {
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errno = -ret;
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err(EXIT_FAILURE, "error while reading");
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}
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for (j = 0; j < 4; j++) {
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read_partition(&data1[446 + 16 * j], &ext[j]);
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if (!ext[j].nb_sectors_abs)
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continue;
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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;
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}
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}
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ext_partnum += 4;
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} else if ((i + 1) == partition) {
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*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;
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}
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}
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return -ENOENT;
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}
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static void termsig_handler(int signum)
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{
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state = TERMINATE;
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qemu_notify_event();
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}
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static void *show_parts(void *arg)
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{
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char *device = arg;
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int nbd;
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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);
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if (nbd >= 0) {
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close(nbd);
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}
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return NULL;
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}
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static void *nbd_client_thread(void *arg)
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{
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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;
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sock = unix_socket_outgoing(sockpath);
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if (sock < 0) {
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goto out;
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}
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ret = nbd_receive_negotiate(sock, NULL, &nbdflags,
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&size, &blocksize);
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if (ret < 0) {
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goto out;
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}
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fd = open(device, O_RDWR);
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if (fd < 0) {
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/* 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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}
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ret = nbd_init(fd, sock, nbdflags, size, blocksize);
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if (ret < 0) {
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goto out;
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}
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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);
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} else {
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/* Close stderr so that the qemu-nbd process exits. */
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dup2(STDOUT_FILENO, STDERR_FILENO);
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}
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ret = nbd_client(fd);
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if (ret) {
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goto out;
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}
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close(fd);
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kill(getpid(), SIGTERM);
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return (void *) EXIT_SUCCESS;
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out:
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kill(getpid(), SIGTERM);
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return (void *) EXIT_FAILURE;
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}
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static int nbd_can_accept(void *opaque)
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{
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return nb_fds < shared;
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}
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static void nbd_export_closed(NBDExport *exp)
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{
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assert(state == TERMINATING);
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state = TERMINATED;
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}
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static void nbd_client_closed(NBDClient *client)
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{
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nb_fds--;
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if (nb_fds == 0 && !persistent && state == RUNNING) {
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state = TERMINATE;
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}
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qemu_notify_event();
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nbd_client_put(client);
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}
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static void nbd_accept(void *opaque)
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{
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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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int fd = accept(server_fd, (struct sockaddr *)&addr, &addr_len);
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if (state >= TERMINATE) {
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close(fd);
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return;
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}
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if (fd >= 0 && nbd_client_new(exp, fd, nbd_client_closed)) {
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nb_fds++;
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}
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}
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int main(int argc, char **argv)
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{
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BlockDriverState *bs;
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off_t dev_offset = 0;
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uint32_t nbdflags = 0;
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bool disconnect = false;
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const char *bindto = "0.0.0.0";
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char *device = NULL;
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int port = NBD_DEFAULT_PORT;
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off_t fd_size;
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const char *sopt = "hVb:o:p:rsnP:c:dvk:e:t";
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struct option lopt[] = {
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{ "help", 0, NULL, 'h' },
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{ "version", 0, NULL, 'V' },
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{ "bind", 1, NULL, 'b' },
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{ "port", 1, NULL, 'p' },
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{ "socket", 1, NULL, 'k' },
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{ "offset", 1, NULL, 'o' },
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{ "read-only", 0, NULL, 'r' },
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{ "partition", 1, NULL, 'P' },
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{ "connect", 1, NULL, 'c' },
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{ "disconnect", 0, NULL, 'd' },
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{ "snapshot", 0, NULL, 's' },
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{ "nocache", 0, NULL, 'n' },
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{ "cache", 1, NULL, QEMU_NBD_OPT_CACHE },
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#ifdef CONFIG_LINUX_AIO
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{ "aio", 1, NULL, QEMU_NBD_OPT_AIO },
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#endif
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{ "shared", 1, NULL, 'e' },
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{ "persistent", 0, NULL, 't' },
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{ "verbose", 0, NULL, 'v' },
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{ NULL, 0, NULL, 0 }
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};
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int ch;
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int opt_ind = 0;
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int li;
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char *end;
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int flags = BDRV_O_RDWR;
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int partition = -1;
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int ret;
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int fd;
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bool seen_cache = false;
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#ifdef CONFIG_LINUX_AIO
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bool seen_aio = false;
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#endif
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pthread_t client_thread;
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/* The client thread uses SIGTERM to interrupt the server. A signal
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* handler ensures that "qemu-nbd -v -c" exits with a nice status code.
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*/
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struct sigaction sa_sigterm;
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memset(&sa_sigterm, 0, sizeof(sa_sigterm));
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sa_sigterm.sa_handler = termsig_handler;
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sigaction(SIGTERM, &sa_sigterm, NULL);
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while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
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switch (ch) {
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case 's':
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flags |= BDRV_O_SNAPSHOT;
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break;
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case 'n':
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optarg = (char *) "none";
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/* fallthrough */
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case QEMU_NBD_OPT_CACHE:
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if (seen_cache) {
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errx(EXIT_FAILURE, "-n and --cache can only be specified once");
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}
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seen_cache = true;
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if (bdrv_parse_cache_flags(optarg, &flags) == -1) {
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errx(EXIT_FAILURE, "Invalid cache mode `%s'", optarg);
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}
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break;
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#ifdef CONFIG_LINUX_AIO
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case QEMU_NBD_OPT_AIO:
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if (seen_aio) {
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errx(EXIT_FAILURE, "--aio can only be specified once");
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}
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seen_aio = true;
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if (!strcmp(optarg, "native")) {
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flags |= BDRV_O_NATIVE_AIO;
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} else if (!strcmp(optarg, "threads")) {
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/* this is the default */
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} else {
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errx(EXIT_FAILURE, "invalid aio mode `%s'", optarg);
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}
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break;
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#endif
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case 'b':
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bindto = optarg;
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break;
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case 'p':
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li = strtol(optarg, &end, 0);
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if (*end) {
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errx(EXIT_FAILURE, "Invalid port `%s'", optarg);
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}
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if (li < 1 || li > 65535) {
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errx(EXIT_FAILURE, "Port out of range `%s'", optarg);
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}
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port = (uint16_t)li;
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break;
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case 'o':
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dev_offset = strtoll (optarg, &end, 0);
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if (*end) {
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errx(EXIT_FAILURE, "Invalid offset `%s'", optarg);
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}
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if (dev_offset < 0) {
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errx(EXIT_FAILURE, "Offset must be positive `%s'", optarg);
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}
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break;
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case 'r':
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nbdflags |= NBD_FLAG_READ_ONLY;
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flags &= ~BDRV_O_RDWR;
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break;
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case 'P':
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partition = strtol(optarg, &end, 0);
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if (*end)
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errx(EXIT_FAILURE, "Invalid partition `%s'", optarg);
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if (partition < 1 || partition > 8)
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errx(EXIT_FAILURE, "Invalid partition %d", partition);
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break;
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case 'k':
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sockpath = optarg;
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if (sockpath[0] != '/')
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errx(EXIT_FAILURE, "socket path must be absolute\n");
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break;
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case 'd':
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disconnect = true;
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break;
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case 'c':
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device = optarg;
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break;
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case 'e':
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shared = strtol(optarg, &end, 0);
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if (*end) {
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errx(EXIT_FAILURE, "Invalid shared device number '%s'", optarg);
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}
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if (shared < 1) {
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errx(EXIT_FAILURE, "Shared device number must be greater than 0\n");
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}
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break;
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case 't':
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persistent = 1;
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break;
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case 'v':
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verbose = 1;
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break;
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case 'V':
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version(argv[0]);
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exit(0);
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break;
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case 'h':
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usage(argv[0]);
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exit(0);
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break;
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case '?':
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errx(EXIT_FAILURE, "Try `%s --help' for more information.",
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argv[0]);
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}
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}
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if ((argc - optind) != 1) {
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errx(EXIT_FAILURE, "Invalid number of argument.\n"
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"Try `%s --help' for more information.",
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argv[0]);
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}
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if (disconnect) {
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fd = open(argv[optind], O_RDWR);
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if (fd < 0) {
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err(EXIT_FAILURE, "Cannot open %s", argv[optind]);
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}
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nbd_disconnect(fd);
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close(fd);
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printf("%s disconnected\n", argv[optind]);
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return 0;
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}
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if (device && !verbose) {
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int stderr_fd[2];
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pid_t pid;
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int ret;
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if (qemu_pipe(stderr_fd) < 0) {
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err(EXIT_FAILURE, "Error setting up communication pipe");
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}
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/* Now daemonize, but keep a communication channel open to
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* print errors and exit with the proper status code.
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*/
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pid = fork();
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if (pid == 0) {
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close(stderr_fd[0]);
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ret = qemu_daemon(1, 0);
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/* Temporarily redirect stderr to the parent's pipe... */
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dup2(stderr_fd[1], STDERR_FILENO);
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if (ret < 0) {
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err(EXIT_FAILURE, "Failed to daemonize");
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}
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/* ... close the descriptor we inherited and go on. */
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close(stderr_fd[1]);
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} else {
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bool errors = false;
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char *buf;
|
|
|
|
/* In the parent. Print error messages from the child until
|
|
* it closes the pipe.
|
|
*/
|
|
close(stderr_fd[1]);
|
|
buf = g_malloc(1024);
|
|
while ((ret = read(stderr_fd[0], buf, 1024)) > 0) {
|
|
errors = true;
|
|
ret = qemu_write_full(STDERR_FILENO, buf, ret);
|
|
if (ret < 0) {
|
|
exit(EXIT_FAILURE);
|
|
}
|
|
}
|
|
if (ret < 0) {
|
|
err(EXIT_FAILURE, "Cannot read from daemon");
|
|
}
|
|
|
|
/* Usually the daemon should not print any message.
|
|
* Exit with zero status in that case.
|
|
*/
|
|
exit(errors);
|
|
}
|
|
}
|
|
|
|
if (device != NULL && sockpath == NULL) {
|
|
sockpath = g_malloc(128);
|
|
snprintf(sockpath, 128, SOCKET_PATH, basename(device));
|
|
}
|
|
|
|
bdrv_init();
|
|
atexit(bdrv_close_all);
|
|
|
|
bs = bdrv_new("hda");
|
|
srcpath = argv[optind];
|
|
if ((ret = bdrv_open(bs, srcpath, flags, NULL)) < 0) {
|
|
errno = -ret;
|
|
err(EXIT_FAILURE, "Failed to bdrv_open '%s'", argv[optind]);
|
|
}
|
|
|
|
fd_size = bdrv_getlength(bs);
|
|
|
|
if (partition != -1) {
|
|
ret = find_partition(bs, partition, &dev_offset, &fd_size);
|
|
if (ret < 0) {
|
|
errno = -ret;
|
|
err(EXIT_FAILURE, "Could not find partition %d", partition);
|
|
}
|
|
}
|
|
|
|
exp = nbd_export_new(bs, dev_offset, fd_size, nbdflags, nbd_export_closed);
|
|
|
|
if (sockpath) {
|
|
fd = unix_socket_incoming(sockpath);
|
|
} else {
|
|
fd = tcp_socket_incoming(bindto, port);
|
|
}
|
|
|
|
if (fd < 0) {
|
|
return 1;
|
|
}
|
|
|
|
if (device) {
|
|
int ret;
|
|
|
|
ret = pthread_create(&client_thread, NULL, nbd_client_thread, device);
|
|
if (ret != 0) {
|
|
errx(EXIT_FAILURE, "Failed to create client thread: %s",
|
|
strerror(ret));
|
|
}
|
|
} else {
|
|
/* Shut up GCC warnings. */
|
|
memset(&client_thread, 0, sizeof(client_thread));
|
|
}
|
|
|
|
qemu_init_main_loop();
|
|
qemu_set_fd_handler2(fd, nbd_can_accept, nbd_accept, NULL,
|
|
(void *)(uintptr_t)fd);
|
|
|
|
/* now when the initialization is (almost) complete, chdir("/")
|
|
* to free any busy filesystems */
|
|
if (chdir("/") < 0) {
|
|
err(EXIT_FAILURE, "Could not chdir to root directory");
|
|
}
|
|
|
|
state = RUNNING;
|
|
do {
|
|
main_loop_wait(false);
|
|
if (state == TERMINATE) {
|
|
state = TERMINATING;
|
|
nbd_export_close(exp);
|
|
nbd_export_put(exp);
|
|
exp = NULL;
|
|
}
|
|
} while (state != TERMINATED);
|
|
|
|
bdrv_close(bs);
|
|
if (sockpath) {
|
|
unlink(sockpath);
|
|
}
|
|
|
|
if (device) {
|
|
void *ret;
|
|
pthread_join(client_thread, &ret);
|
|
exit(ret != NULL);
|
|
} else {
|
|
exit(EXIT_SUCCESS);
|
|
}
|
|
}
|