nbd-client: support newstyle protocol, -b, -d, -p, -N
authorDenys Vlasenko <vda.linux@googlemail.com>
Wed, 24 Oct 2018 13:51:38 +0000 (15:51 +0200)
committerDenys Vlasenko <vda.linux@googlemail.com>
Wed, 24 Oct 2018 13:52:04 +0000 (15:52 +0200)
Recognize the "newstyle" protocol and switch to it automatically.
Add options for setting blocksize (-b) and for disconnecting
a nbd device (-d).

function                                             old     new   delta
nbdclient_main                                       492    1179    +687
static.long_options                                    -      80     +80
print_direc                                          438     457     +19
brctl_main                                          1169    1183     +14
bb_strtoll                                            84      89      +5
packed_usage                                       33082   33066     -16
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 4/1 up/down: 805/-16)           Total: 789 bytes

Signed-off-by: Elvira Khabirova <lineprinter@altlinux.org>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
networking/nbd-client.c

index bedb01a1c33f744137c88d2bfc9c7bf28497b718..103756b59783cc22cf89c18942a1314fef0f4335 100644 (file)
@@ -16,6 +16,7 @@
 #include "libbb.h"
 #include <netinet/tcp.h>
 #include <linux/fs.h>
+#include <getopt.h>
 
 #define NBD_SET_SOCK          _IO(0xab, 0)
 #define NBD_SET_BLKSIZE       _IO(0xab, 1)
 #define NBD_SET_SIZE_BLOCKS   _IO(0xab, 7)
 #define NBD_DISCONNECT        _IO(0xab, 8)
 #define NBD_SET_TIMEOUT       _IO(0xab, 9)
+#define NBD_SET_FLAGS         _IO(0xab, 10)
 
 //usage:#define nbdclient_trivial_usage
-//usage:       "HOST PORT BLOCKDEV"
+//usage:       "{ [-b BLKSIZE] [-N NAME] [-t SEC] [-p] HOST [PORT] | -d } BLOCKDEV"
 //usage:#define nbdclient_full_usage "\n\n"
-//usage:       "Connect to HOST and provide network block device on BLOCKDEV"
+//usage:       "Connect to HOST and provide network block device on BLOCKDEV"
 
-//TODO: more compat with nbd-client version 2.9.13 -
-//Usage: nbd-client [bs=blocksize] [timeout=sec] host port nbd_device [-swap] [-persist] [-nofork]
-//Or   : nbd-client -d nbd_device
-//Or   : nbd-client -c nbd_device
-//Default value for blocksize is 1024 (recommended for ethernet)
+//TODO: more compat with nbd-client version 3.17 -
+//nbd-client host [ port ] nbd-device [ -connections num ] [ -sdp ] [ -swap ]
+//     [ -persist ] [ -nofork ] [ -nonetlink ] [ -systemd-mark ]
+//     [ -block-size block size ] [ -timeout seconds ] [ -name name ]
+//     [ -certfile certfile ] [ -keyfile keyfile ] [ -cacertfile cacertfile ]
+//     [ -tlshostname hostname ]
+//nbd-client -unix path nbd-device [ -connections num ] [ -sdp ] [ -swap ]
+//     [ -persist ] [ -nofork ] [ -nonetlink ] [ -systemd-mark ]
+//     [ -block-size block size ] [ -timeout seconds ] [ -name name ]
+//nbd-client nbd-device
+//nbd-client -d nbd-device
+//nbd-client -c nbd-device
+//nbd-client -l host [ port ]
+//nbd-client [ -netlink ] -l host
+//
+//Default value for blocksize is 4096
 //Allowed values for blocksize are 512,1024,2048,4096
-//Note, that kernel 2.4.2 and older ones do not work correctly with
-//blocksizes other than 1024 without patches
 
 int nbdclient_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
-int nbdclient_main(int argc UNUSED_PARAM, char **argv)
+int nbdclient_main(int argc, char **argv)
 {
-       unsigned long timeout = 0;
 #if BB_MMU
-       int nofork = 0;
+       bool nofork;
 #endif
-       char *host, *port, *device;
+       bool opt_d;
+       bool opt_p;
+       const char *host, *port, *device;
+       const char *name;
+       unsigned blksize, size_blocks;
+       unsigned timeout;
+       int ch;
        struct nbd_header_t {
                uint64_t magic1; // "NBDMAGIC"
-               uint64_t magic2; // 0x420281861253 big endian
+               uint64_t magic2; // old style: 0x420281861253 big endian
+               //               // new style: 0x49484156454F5054 (IHAVEOPT)
+       } nbd_header;
+       struct old_nbd_header_t {
                uint64_t devsize;
                uint32_t flags;
                char data[124];
-       } nbd_header;
+       } old_nbd_header;
+       struct new_nbd_header_t {
+               uint64_t devsize;
+               uint16_t transmission_flags;
+               char data[124];
+       } new_nbd_header;
+       struct nbd_opt_t {
+               uint64_t magic;
+               uint32_t opt;
+               uint32_t len;
+       } nbd_opts;
 
-       BUILD_BUG_ON(offsetof(struct nbd_header_t, data) != 8+8+8+4);
+       static const struct option long_options[] = {
+               { "block-size", required_argument, NULL, 'b' },
+               { "timeout"   , required_argument, NULL, 't' },
+               { "name"      , required_argument, NULL, 'n' },
+               { "persist"   , no_argument      , NULL, 'p' },
+               { NULL }
+       };
 
-       // Parse command line stuff (just a stub now)
-       if (!argv[1] || !argv[2] || !argv[3] || argv[4])
-               bb_show_usage();
+       BUILD_BUG_ON(offsetof(struct old_nbd_header_t, data) != 8 + 4);
+       BUILD_BUG_ON(offsetof(struct new_nbd_header_t, data) != 8 + 2);
 
 #if !BB_MMU
        bb_daemonize_or_rexec(DAEMON_CLOSE_EXTRA_FDS, argv);
 #endif
 
-       host = argv[1];
-       port = argv[2];
-       device = argv[3];
+       // Parse args. nbd-client uses stupid "one-dash long options" style :(
+       // Even though short forms (-b,-t,-N,-p) exist for all long opts,
+       // older manpages only contained long forms, which probably resulted
+       // in many scripts using them.
+       blksize = 4096;
+       timeout = 0;
+       name = ""; // use of "" instead of NULL simplifies strlen() later
+       opt_d = opt_p = 0;
+       while ((ch = getopt_long_only(argc, argv, "dN:", long_options, NULL)) != -1) {
+               switch (ch) {
+               case 'p':       // -persist
+                       opt_p = 1;
+                       break;
+               case 'd':       // -d
+                       opt_d = 1;
+                       break;
+               case 'b':       // -block-size
+                       blksize = xatou(optarg);
+                       break;
+               case 't':       // -timeout
+                       timeout = xatou(optarg);
+                       break;
+               case 'N':       // -N
+               case 'n':       // -name
+                       name = optarg;
+                       break;
+               default:
+                       bb_show_usage();
+               }
+       }
+       argv += optind;
+
+       if (opt_d) { // -d
+               if (argv[0] && !argv[1]) {
+                       int nbd = xopen(argv[0], O_RDWR);
+                       ioctl(nbd, NBD_DISCONNECT);
+                       ioctl(nbd, NBD_CLEAR_SOCK);
+                       if (ENABLE_FEATURE_CLEAN_UP)
+                               close(nbd);
+                       return 0;
+               }
+               bb_show_usage();
+       }
+
+       // Allow only argv[] of: HOST [PORT] BLOCKDEV
+       if (!argv[0] || !argv[1] || (argv[2] && argv[3])) {
+               bb_show_usage();
+       }
 
-       // Repeat until spanked (-persist behavior)
-       for (;;) {
+       host = argv[0];
+       port = argv[2] ? argv[1] : "10809";
+       device = argv[2] ? argv[2] : argv[1];
+
+       // Repeat until spanked if -persist
+#if BB_MMU
+       nofork = 0;
+#endif
+       do {
                int sock, nbd;
                int ro;
+               int proto_new; // 0 for old, 1 for new
+               char *data;
 
-               // Make sure the /dev/nbd exists
+               // Make sure BLOCKDEV exists
                nbd = xopen(device, O_RDWR);
 
                // Find and connect to server
@@ -85,40 +173,95 @@ int nbdclient_main(int argc UNUSED_PARAM, char **argv)
                setsockopt_1(sock, IPPROTO_TCP, TCP_NODELAY);
 
                // Log on to the server
-               xread(sock, &nbd_header, 8+8+8+4 + 124);
-               if (memcmp(&nbd_header.magic1, "NBDMAGIC""\x00\x00\x42\x02\x81\x86\x12\x53", 16) != 0)
+               xread(sock, &nbd_header, 8 + 8);
+               if (memcmp(&nbd_header.magic1, "NBDMAGIC",
+                               sizeof(nbd_header.magic1)) != 0
+               ) {
+                       bb_error_msg_and_die("login failed");
+               }
+               if (memcmp(&nbd_header.magic2,
+                               "\x00\x00\x42\x02\x81\x86\x12\x53",
+                               sizeof(nbd_header.magic2)) == 0
+               ) {
+                       proto_new = 0;
+               } else if (memcmp(&nbd_header.magic2, "IHAVEOPT", 8) == 0) {
+                       proto_new = 1;
+               } else {
                        bb_error_msg_and_die("login failed");
+               }
+
+               if (!proto_new) {
+                       xread(sock, &old_nbd_header,
+                                       sizeof(old_nbd_header.devsize) +
+                                       sizeof(old_nbd_header.flags) +
+                                       sizeof(old_nbd_header.data));
+                       size_blocks = SWAP_BE64(old_nbd_header.devsize) / blksize;
+                       ioctl(nbd, NBD_SET_BLKSIZE, (unsigned long) blksize);
+                       ioctl(nbd, NBD_SET_SIZE_BLOCKS, size_blocks);
+                       ioctl(nbd, NBD_CLEAR_SOCK);
+                       ro = !!(old_nbd_header.flags & htons(2));
+                       data = old_nbd_header.data;
+               } else {
+                       unsigned namelen;
+                       uint16_t handshake_flags;
+
+                       xread(sock, &handshake_flags, sizeof(handshake_flags));
+                       xwrite(sock, &const_int_0, sizeof(const_int_0)); // client_flags
+
+                       memcpy(&nbd_opts.magic, "IHAVEOPT",
+                                       sizeof(nbd_opts.magic));
+                       nbd_opts.opt = htonl(1); // NBD_OPT_EXPORT_NAME
+                       namelen = strlen(name);
+                       nbd_opts.len = htonl(namelen);
+                       xwrite(sock, &nbd_opts,
+                                       sizeof(nbd_opts.magic) +
+                                       sizeof(nbd_opts.opt) +
+                                       sizeof(nbd_opts.len));
+                       xwrite(sock, name, namelen);
 
-               // Set 4k block size.  Everything uses that these days
-               ioctl(nbd, NBD_SET_BLKSIZE, 4096);
-               ioctl(nbd, NBD_SET_SIZE_BLOCKS, SWAP_BE64(nbd_header.devsize) / 4096);
-               ioctl(nbd, NBD_CLEAR_SOCK);
+                       xread(sock, &new_nbd_header,
+                                       sizeof(new_nbd_header.devsize) +
+                                       sizeof(new_nbd_header.transmission_flags) +
+                                       sizeof(new_nbd_header.data));
+                       size_blocks = SWAP_BE64(new_nbd_header.devsize) / blksize;
+                       ioctl(nbd, NBD_SET_BLKSIZE, (unsigned long) blksize);
+                       ioctl(nbd, NBD_SET_SIZE_BLOCKS, size_blocks);
+                       ioctl(nbd, NBD_CLEAR_SOCK);
+                       ioctl(nbd, NBD_SET_FLAGS,
+                                       ntohs(new_nbd_header.transmission_flags));
+                       ro = !!(new_nbd_header.transmission_flags & htons(2));
+                       data = new_nbd_header.data;
+               }
 
-               // If the sucker was exported read only, respect that locally
-               ro = (nbd_header.flags & SWAP_BE32(2)) / SWAP_BE32(2);
-               if (ioctl(nbd, BLKROSET, &ro) < 0)
+               if (ioctl(nbd, BLKROSET, &ro) < 0) {
                        bb_perror_msg_and_die("BLKROSET");
+               }
 
-               if (timeout)
-                       if (ioctl(nbd, NBD_SET_TIMEOUT, timeout))
+               if (timeout) {
+                       if (ioctl(nbd, NBD_SET_TIMEOUT, (unsigned long) timeout)) {
                                bb_perror_msg_and_die("NBD_SET_TIMEOUT");
-               if (ioctl(nbd, NBD_SET_SOCK, sock))
-                       bb_perror_msg_and_die("NBD_SET_SOCK");
+                       }
+               }
 
-               // if (swap) mlockall(MCL_CURRENT|MCL_FUTURE);
+               if (ioctl(nbd, NBD_SET_SOCK, sock)) {
+                       bb_perror_msg_and_die("NBD_SET_SOCK");
+               }
 
+               //if (swap) mlockall(MCL_CURRENT|MCL_FUTURE);
 #if BB_MMU
                // Open the device to force reread of the partition table.
                // Need to do it in a separate process, since open(device)
                // needs some other process to sit in ioctl(nbd, NBD_DO_IT).
                if (fork() == 0) {
+                       /* child */
                        char *s = strrchr(device, '/');
-                       sprintf(nbd_header.data, "/sys/block/%.32s/pid", s ? s + 1 : device);
+                       sprintf(data, "/sys/block/%.32s/pid", s ? s + 1 : device);
                        // Is it up yet?
                        for (;;) {
-                               int fd = open(nbd_header.data, O_RDONLY);
+                               int fd = open(data, O_RDONLY);
                                if (fd >= 0) {
-                                       //close(fd);
+                                       if (ENABLE_FEATURE_CLEAN_UP)
+                                               close(fd);
                                        break;
                                }
                                sleep(1);
@@ -133,7 +276,6 @@ int nbdclient_main(int argc UNUSED_PARAM, char **argv)
                        nofork = 1;
                }
 #endif
-
                // This turns us (the process that calls this ioctl)
                // into a dedicated NBD request handler.
                // We block here for a long time.
@@ -148,7 +290,7 @@ int nbdclient_main(int argc UNUSED_PARAM, char **argv)
 
                close(sock);
                close(nbd);
-       }
+       } while (opt_p);
 
        return 0;
 }