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-rw-r--r--toys/other/nbd_client.c128
1 files changed, 128 insertions, 0 deletions
diff --git a/toys/other/nbd_client.c b/toys/other/nbd_client.c
new file mode 100644
index 00000000..33787d77
--- /dev/null
+++ b/toys/other/nbd_client.c
@@ -0,0 +1,128 @@
+/* nbd-client.c - network block device client
+ *
+ * Copyright 2010 Rob Landley <rob@landley.net>
+ *
+ * Not in SUSv4.
+
+// This little dance is because a NEWTOY with - in the name tries to do
+// things like prototype "nbd-client_main" which isn't a valid symbol. So
+// we hide the underscore name and OLDTOY the name we want.
+USE_NBD_CLIENT(NEWTOY(nbd_client, "<3>3ns", 0))
+USE_NBD_CLIENT(OLDTOY(nbd-client, nbd_client, OPTSTR_nbd_client, TOYFLAG_USR|TOYFLAG_BIN))
+
+config NBD_CLIENT
+ bool "nbd-client"
+ default y
+ help
+ usage: nbd-client [-ns] HOST PORT DEVICE
+
+ -n Do not fork into background
+ -s nbd swap support (lock server into memory)
+*/
+
+/* TODO:
+ usage: nbd-client [-sSpn] [-b BLKSZ] [-t SECS] [-N name] HOST PORT DEVICE
+
+ -b block size
+ -t timeout in seconds
+ -S sdp
+ -p persist
+ -n nofork
+ -d DEVICE
+ -c DEVICE
+*/
+
+#define FOR_nbd_client
+#include "toys.h"
+#include <linux/nbd.h>
+
+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;
+
+ // Repeat until spanked
+
+ nbd = xopen(device, O_RDWR);
+ 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;
+ close(sock);
+ }
+ freeaddrinfo(addr);
+
+ if (!p) perror_exit("%s:%s", host, port);
+
+ temp = 1;
+ setsockopt(sock, IPPROTO_TCP, TCP_NODELAY, &temp, sizeof(int));
+
+ // Read login data
+
+ xreadall(sock, toybuf, 152);
+ if (memcmp(toybuf, "NBDMAGIC\x00\x00\x42\x02\x81\x86\x12\x53", 16))
+ error_exit("bad login %s:%s", host, port);
+ devsize = SWAP_BE64(*(uint64_t *)(toybuf+16));
+ flags = SWAP_BE32(*(int *)(toybuf+24));
+
+ // 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;
+ xioctl(nbd, BLKROSET, &temp);
+
+ if (timeout && ioctl(nbd, NBD_SET_TIMEOUT, timeout)<0) break;
+ if (ioctl(nbd, NBD_SET_SOCK, sock) < 0) break;
+
+ if (toys.optflags & FLAG_s) mlockall(MCL_CURRENT|MCL_FUTURE);
+
+ // Open the device to force reread of the partition table.
+ if ((toys.optflags & FLAG_n) || !xfork()) {
+ char *s = strrchr(device, '/');
+ int i;
+
+ sprintf(toybuf, "/sys/block/%.32s/pid", s ? s+1 : device);
+ // Is it up yet? (Give it 10 seconds.)
+ for (i=0; i<100; i++) {
+ temp = open(toybuf, O_RDONLY);
+ if (temp == -1) msleep(100);
+ else {
+ close(temp);
+ break;
+ }
+ }
+ close(open(device, O_RDONLY));
+ if (!(toys.optflags & FLAG_n)) 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_QUE);
+ ioctl(nbd, NBD_CLEAR_SOCK);
+}