[Qemu-devel] [4834] Merge NBD client/server, by Laurent Vivier.

[Thiemo Seufer]

Revision: 4834
          http://svn.sv.gnu.org/viewvc/?view=rev&root=qemu&revision=4834
Author:   ths
Date:     2008-07-03 10:23:51 +0000 (Thu, 03 Jul 2008)

Log Message:
-----------
Merge NBD client/server, by Laurent Vivier.

Modified Paths:
--------------
    trunk/nbd.c
    trunk/nbd.h
    trunk/qemu-nbd.c
    trunk/qemu-nbd.texi

Modified: trunk/nbd.c
===================================================================
--- trunk/nbd.c 2008-07-03 10:01:15 UTC (rev 4833)
+++ trunk/nbd.c 2008-07-03 10:23:51 UTC (rev 4834)
@@ -25,6 +25,7 @@
 #include <ctype.h>
 #include <inttypes.h>
 #include <sys/socket.h>
+#include <sys/un.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
 #include <arpa/inet.h>
@@ -183,6 +184,65 @@
     return -1;
 }
 
+int unix_socket_incoming(const char *path)
+{
+    int s;
+    struct sockaddr_un addr;
+    int serrno;
+
+    s = socket(PF_UNIX, SOCK_STREAM, 0);
+    if (s == -1) {
+        return -1;
+    }
+
+    memset(&addr, 0, sizeof(addr));
+    addr.sun_family = AF_UNIX;
+    pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
+
+    if (bind(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
+        goto error;
+    }
+
+    if (listen(s, 128) == -1) {
+        goto error;
+    }
+
+    return s;
+error:
+    serrno = errno;
+    close(s);
+    errno = serrno;
+    return -1;
+}
+
+int unix_socket_outgoing(const char *path)
+{
+    int s;
+    struct sockaddr_un addr;
+    int serrno;
+
+    s = socket(PF_UNIX, SOCK_STREAM, 0);
+    if (s == -1) {
+        return -1;
+    }
+
+    memset(&addr, 0, sizeof(addr));
+    addr.sun_family = AF_UNIX;
+    pstrcpy(addr.sun_path, sizeof(addr.sun_path), path);
+
+    if (connect(s, (struct sockaddr *)&addr, sizeof(addr)) == -1) {
+        goto error;
+    }
+
+    return s;
+error:
+    serrno = errno;
+    close(s);
+    errno = serrno;
+    return -1;
+}
+
+
 /* Basic flow
 
    Server         Client
@@ -225,12 +285,10 @@
        return 0;
 }
 
-int nbd_receive_negotiate(int fd, int csock)
+int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize)
 {
        char buf[8 + 8 + 8 + 128];
        uint64_t magic;
-       off_t size;
-       size_t blocksize;
 
        TRACE("Receiving negotation.");
 
@@ -241,8 +299,8 @@
        }
 
        magic = be64_to_cpup((uint64_t*)(buf + 8));
-       size = be64_to_cpup((uint64_t*)(buf + 16));
-       blocksize = 1024;
+       *size = be64_to_cpup((uint64_t*)(buf + 16));
+       *blocksize = 1024;
 
        TRACE("Magic is %c%c%c%c%c%c%c%c",
              isprint(buf[0]) ? buf[0] : '.',
@@ -254,7 +312,7 @@
              isprint(buf[6]) ? buf[6] : '.',
              isprint(buf[7]) ? buf[7] : '.');
        TRACE("Magic is 0x%" PRIx64, magic);
-       TRACE("Size is %" PRIu64, size);
+       TRACE("Size is %" PRIu64, *size);
 
        if (memcmp(buf, "NBDMAGIC", 8) != 0) {
                LOG("Invalid magic received");
@@ -269,7 +327,11 @@
                errno = EINVAL;
                return -1;
        }
+        return 0;
+}
 
+int nbd_init(int fd, int csock, off_t size, size_t blocksize)
+{
        TRACE("Setting block size to %lu", (unsigned long)blocksize);
 
        if (ioctl(fd, NBD_SET_BLKSIZE, blocksize) == -1) {

Modified: trunk/nbd.h
===================================================================
--- trunk/nbd.h 2008-07-03 10:01:15 UTC (rev 4833)
+++ trunk/nbd.h 2008-07-03 10:23:51 UTC (rev 4834)
@@ -27,9 +27,12 @@
 #include "block_int.h"
 
 int tcp_socket_incoming(const char *address, uint16_t port);
+int unix_socket_outgoing(const char *path);
+int unix_socket_incoming(const char *path);
 
 int nbd_negotiate(BlockDriverState *bs, int csock, off_t size);
-int nbd_receive_negotiate(int fd, int csock);
+int nbd_receive_negotiate(int csock, off_t *size, size_t *blocksize);
+int nbd_init(int fd, int csock, off_t size, size_t blocksize);
 int nbd_trip(BlockDriverState *bs, int csock, off_t size, uint64_t dev_offset, 
off_t *offset, bool readonly);
 int nbd_client(int fd, int csock);
 int nbd_disconnect(int fd);

Modified: trunk/qemu-nbd.c
===================================================================
--- trunk/qemu-nbd.c    2008-07-03 10:01:15 UTC (rev 4833)
+++ trunk/qemu-nbd.c    2008-07-03 10:23:51 UTC (rev 4834)
@@ -1,4 +1,4 @@
-/*\
+/*
  *  Copyright (C) 2005  Anthony Liguori <address@hidden>
  *
  *  Network Block Device
@@ -25,11 +25,15 @@
 #include <stdio.h>
 #include <getopt.h>
 #include <err.h>
+#include <sys/types.h>
 #include <sys/socket.h>
 #include <netinet/in.h>
 #include <netinet/tcp.h>
 #include <arpa/inet.h>
+#include <signal.h>
 
+#define SOCKET_PATH    "/var/lock/qemu-nbd-%s"
+
 int verbose;
 
 static void usage(const char *name)
@@ -41,14 +45,18 @@
 "  -p, --port=PORT      port to listen on (default `1024')\n"
 "  -o, --offset=OFFSET  offset into the image\n"
 "  -b, --bind=IFACE     interface to bind to (default `0.0.0.0')\n"
+"  -k, --socket=PATH    path to the unix socket\n"
+"                       (default '"SOCKET_PATH"')\n"
 "  -r, --read-only      export read-only\n"
 "  -P, --partition=NUM  only expose partition NUM\n"
+"  -c, --connect=DEV    connect FILE to the local NBD device DEV\n"
+"  -d, --disconnect     disconnect the specified device\n"
 "  -v, --verbose        display extra debugging information\n"
 "  -h, --help           display this help and exit\n"
 "  -V, --version        output version information and exit\n"
 "\n"
 "Report bugs to <address@hidden>\n"
-    , name);
+    , name, "DEVICE");
 }
 
 static void version(const char *name)
@@ -144,27 +152,51 @@
     return -1;
 }
 
+static void show_parts(const char *device)
+{
+    if (fork() == 0) {
+        int nbd;
+
+        /* linux just needs an open() to trigger
+         * the partition table update
+         * but remember to load the module with max_part != 0 :
+         *     modprobe nbd max_part=63
+         */
+        nbd = open(device, O_RDWR);
+        if (nbd != -1)
+              close(nbd);
+        exit(0);
+    }
+}
+
 int main(int argc, char **argv)
 {
     BlockDriverState *bs;
     off_t dev_offset = 0;
     off_t offset = 0;
     bool readonly = false;
+    bool disconnect = false;
     const char *bindto = "0.0.0.0";
     int port = 1024;
     int sock, csock;
     struct sockaddr_in addr;
     socklen_t addr_len = sizeof(addr);
     off_t fd_size;
-    const char *sopt = "hVbo:p:rsP:v";
+    char *device = NULL;
+    char *socket = NULL;
+    char sockpath[128];
+    const char *sopt = "hVbo:p:rsP:c:dvk:";
     struct option lopt[] = {
         { "help", 0, 0, 'h' },
         { "version", 0, 0, 'V' },
         { "bind", 1, 0, 'b' },
         { "port", 1, 0, 'p' },
+        { "socket", 1, 0, 'k' },
         { "offset", 1, 0, 'o' },
         { "read-only", 0, 0, 'r' },
         { "partition", 1, 0, 'P' },
+        { "connect", 1, 0, 'c' },
+        { "disconnect", 0, 0, 'd' },
         { "snapshot", 0, 0, 's' },
         { "verbose", 0, 0, 'v' },
         { NULL, 0, 0, 0 }
@@ -175,6 +207,8 @@
     char *end;
     bool snapshot = false;
     int partition = -1;
+    int fd;
+    int ret;
 
     while ((ch = getopt_long(argc, argv, sopt, lopt, &opt_ind)) != -1) {
         switch (ch) {
@@ -213,6 +247,17 @@
             if (partition < 1 || partition > 8)
                 errx(EINVAL, "Invalid partition %d", partition);
             break;
+        case 'k':
+            socket = optarg;
+            if (socket[0] != '/')
+                errx(EINVAL, "socket path must be absolute\n");
+            break;
+        case 'd':
+            disconnect = true;
+            break;
+        case 'c':
+            device = optarg;
+            break;
         case 'v':
             verbose = 1;
             break;
@@ -236,6 +281,20 @@
              argv[0]);
     }
 
+    if (disconnect) {
+        fd = open(argv[optind], O_RDWR);
+        if (fd == -1)
+            errx(errno, "Cannot open %s", argv[optind]);
+
+        nbd_disconnect(fd);
+
+        close(fd);
+
+        printf("%s disconnected\n", argv[optind]);
+
+       return 0;
+    }
+
     bdrv_init();
 
     bs = bdrv_new("hda");
@@ -251,7 +310,77 @@
         find_partition(bs, partition, &dev_offset, &fd_size))
         errx(errno, "Could not find partition %d", partition);
 
-    sock = tcp_socket_incoming(bindto, port);
+    if (device) {
+       pid_t pid;
+       if (!verbose)
+            daemon(0, 0);      /* detach client and server */
+
+        if (socket == NULL) {
+            sprintf(sockpath, SOCKET_PATH, basename(device));
+            socket = sockpath;
+        }
+
+        pid = fork();
+        if (pid < 0)
+            return 1;
+        if (pid != 0) {
+            off_t size;
+            size_t blocksize;
+
+            ret = 0;
+            bdrv_close(bs);
+
+            do {
+                sock = unix_socket_outgoing(socket);
+                if (sock == -1) {
+                    if (errno != ENOENT && errno != ECONNREFUSED)
+                        goto out;
+                    sleep(1);  /* wait children */
+                }
+            } while (sock == -1);
+
+            fd = open(device, O_RDWR);
+            if (fd == -1) {
+                ret = 1;
+                goto out;
+            }
+
+            ret = nbd_receive_negotiate(sock, &size, &blocksize);
+            if (ret == -1) {
+                ret = 1;
+                goto out;
+            }
+
+            ret = nbd_init(fd, sock, size, blocksize);
+            if (ret == -1) {
+                ret = 1;
+                goto out;
+            }
+
+            printf("NBD device %s is now connected to file %s\n",
+                    device, argv[optind]);
+
+           /* update partition table */
+
+            show_parts(device);
+
+            nbd_client(fd, sock);
+            close(fd);
+ out:
+            kill(pid, SIGTERM);
+            unlink(socket);
+
+            return ret;
+        }
+        /* children */
+    }
+
+    if (socket) {
+        sock = unix_socket_incoming(socket);
+    } else {
+        sock = tcp_socket_incoming(bindto, port);
+    }
+
     if (sock == -1)
         return 1;
 
@@ -270,6 +399,8 @@
     close(csock);
     close(sock);
     bdrv_close(bs);
+    if (socket)
+        unlink(socket);
 
     return 0;
 }

Modified: trunk/qemu-nbd.texi
===================================================================
--- trunk/qemu-nbd.texi 2008-07-03 10:01:15 UTC (rev 4833)
+++ trunk/qemu-nbd.texi 2008-07-03 10:23:51 UTC (rev 4834)
@@ -20,10 +20,16 @@
   offset into the image
 @item -b, --bind=IFACE
   interface to bind to (default `0.0.0.0')
address@hidden -k, --socket=PATH
+  Use a unix socket with path PATH
 @item -r, --read-only
   export read-only
 @item -P, --partition=NUM
   only expose partition NUM
address@hidden -c, --connect
+  connect FILE to NBD device DEV
address@hidden -d, --disconnect
+  disconnect the specified device
 @item -v, --verbose
   display extra debugging information
 @item -h, --help