--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toys/pending/nbd_client.c	Mon Mar 18 09:04:51 2013 -0500
@@ -0,0 +1,166 @@
+/* vi: set sw=4 ts=4:
+ *
+ * nbd-client.c - network block device client
+ *
+ * Copyright 2010 Rob Landley <rob@landley.net>
+ *
+ * Not in SUSv4.
+
+USE_NBD_CLIENT(NEWTOY(nbd_client, "<3>3", TOYFLAG_USR|TOYFLAG_BIN))
+
+config NBD_CLIENT
+  bool "nbd-client"
+  default n
+  help
+    Usage: nbd-client [-sSpn] [-b BLKSZ] [-t SECS] [-N name] HOST PORT DEVICE
+
+    -b	block size
+    -t	timeout in seconds
+    -s	swap
+    -S	sdp
+    -p	persist
+    -n	nofork
+    -d	DEVICE
+    -c	DEVICE
+*/
+
+#define FOR_nbd_client
+#include "toys.h"
+
+//#include <errno.h>
+//#include <fcntl.h>
+//#include <limits.h>
+#include <netdb.h>
+//#include <stdint.h>
+//#include <stdio.h>
+//#include <stdlib.h>
+//#include <string.h>
+//#include <unistd.h>
+#include <netinet/tcp.h>
+//#include <sys/ioctl.h>
+//#include <sys/mount.h>
+//#include <sys/types.h>
+//#include <sys/socket.h>
+//#include <sys/stat.h>
+
+#define NBD_SET_SOCK          _IO(0xab, 0)
+#define NBD_SET_BLKSIZE       _IO(0xab, 1)
+#define NBD_SET_SIZE          _IO(0xab, 2)
+#define NBD_DO_IT             _IO(0xab, 3)
+#define NBD_CLEAR_SOCK        _IO(0xab, 4)
+#define NBD_CLEAR_QUEUE       _IO(0xab, 5)
+#define NBD_PRINT_DEBUG       _IO(0xab, 6)
+#define NBD_SET_SIZE_BLOCKS   _IO(0xab, 7)
+#define NBD_DISCONNECT        _IO(0xab, 8)
+#define NBD_SET_TIMEOUT       _IO(0xab, 9)
+
+void nbd_client_main(void)
+{
+  int sock = -1, nbd, flags;
+  unsigned long timeout = 0;
+  struct addrinfo *addr, *p;
+  char *host=toys.optargs[0], *port=toys.optargs[1], *device=toys.optargs[2];
+  uint64_t devsize;
+  char data[124];
+
+  // Parse command line stuff (just a stub now)
+
+  // Make sure the /dev/nbd exists.
+
+  if (0>(nbd = open(device, O_RDWR))) {
+    fprintf(stderr, "Can't open '%s'\n", device);
+    exit(1);
+  }
+
+  // Repeat until spanked
+
+  for (;;) {
+    int temp;
+    struct addrinfo hints;
+
+    // Find and connect to server
+
+    memset(&hints, 0, sizeof(hints));
+    hints.ai_family = PF_UNSPEC;
+    hints.ai_socktype = SOCK_STREAM;
+    if (getaddrinfo(host, port, &hints, &addr)) addr = 0;
+    for (p = addr; p; p = p->ai_next) {
+      sock = socket(p->ai_family, p->ai_socktype, p->ai_protocol);
+      if (-1 != connect(sock, p->ai_addr, p->ai_addrlen)) break;
+    }
+    freeaddrinfo(addr);
+
+    if (!p) {
+      fprintf(stderr, "Can't connect '%s' port '%s'\n", host, port);
+      exit(1);
+    }
+
+    temp = 1;
+    setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, &temp, sizeof(int));
+
+    // Log on to the server.  (Todo: one big 8+8+8+4+124=152 read)
+
+    if (read(sock, data, 8) != 8 || memcmp(data, "NBDMAGIC", 8)
+      || read(sock, &devsize, 8) != 8
+      || SWAP_BE64(devsize) != 0x420281861253LL
+      || read(sock, &devsize, 8) != 8 || read(sock, &flags, 4) != 4
+      || read(sock, data, 124) != 124)
+    {
+      fprintf(stderr, "Login fail\n");
+      exit(1);
+    }
+    devsize = SWAP_BE64(devsize);
+    flags = SWAP_BE32(flags);
+
+    // Set 4k block size.  Everything uses that these days.
+    ioctl(nbd, NBD_SET_BLKSIZE, 4096);
+    ioctl(nbd, NBD_SET_SIZE_BLOCKS, devsize/4096);
+    ioctl(nbd, NBD_CLEAR_SOCK);
+
+    // If the sucker was exported read only, respect that locally.
+    temp = (flags & 2) ? 1 : 0;
+    if (ioctl(nbd, BLKROSET, &temp)<0) {
+      fprintf(stderr, "Login fail\n");
+      exit(1);
+    }
+
+    if (timeout && ioctl(nbd, NBD_SET_TIMEOUT, timeout)<0) break;
+    if (ioctl(nbd, NBD_SET_SOCK, sock) < 0) break;
+
+    // if (swap) mlockall(MCL_CURRENT|MCL_FUTURE);
+
+    // Open the device to force reread of the partition table.
+    if (!fork()) {
+      char *s = strrchr(device, '/');
+      sprintf(data, "/sys/block/%.32s/pid", s ? s+1 : device);
+      // Is it up yet?
+      for (;;) {
+        temp = open(data, O_RDONLY);
+        if (temp == -1) sleep(1);
+        else {
+          close(temp);
+          break;
+        }
+      }
+      close(open(device, O_RDONLY));
+      exit(0);
+    }
+
+    // Daemonize here.
+
+    daemon(0,0);
+
+    // Process NBD requests until further notice.
+
+    if (ioctl(nbd, NBD_DO_IT)>=0 || errno==EBADR) break;
+    close(sock);
+    close(nbd);
+  }
+
+  // Flush queue and exit.
+
+  ioctl(nbd, NBD_CLEAR_QUEUE);
+  ioctl(nbd, NBD_CLEAR_SOCK);
+
+  exit(0);
+}