From 770be29b68b151964aff988de606963eaf04dbe3 Mon Sep 17 00:00:00 2001

From: John Eckersberg <jeckersb@redhat.com>

Date: Fri, 5 Dec 2014 16:58:13 -0500

Subject: [PATCH] p2v: wait for qemu-nbd before starting conversion

 (RHBZ#1167774)

Wait up to 10 seconds for qemu-nbd to start up and respond to clients.

Otherwise the conversion server may attempt to connect before qemu-nbd

is ready to serve it.

(cherry picked from commit 33098d23020bd3824a2954823a0dbaff751c814d)

---

 p2v/conversion.c | 76 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++

 1 file changed, 76 insertions(+)

diff --git a/p2v/conversion.c b/p2v/conversion.c

index cb2deed..9f5a3ad 100644

--- a/p2v/conversion.c

+++ b/p2v/conversion.c

@@ -31,6 +31,8 @@

 #include <libintl.h>

 #include <sys/types.h>

 #include <sys/wait.h>

+#include <arpa/inet.h>

+#include <netinet/in.h>

 #include <glib.h>

@@ -39,6 +41,9 @@

 #include "miniexpect.h"

 #include "p2v.h"

+/* How long to wait for qemu-nbd to start (seconds). */

+#define WAIT_QEMU_NBD_TIMEOUT 10

+

 /* Data per NBD connection / physical disk. */

 struct data_conn {

   mexp_h *h;                /* miniexpect handle to ssh */

@@ -49,6 +54,7 @@ struct data_conn {

 static int send_quoted (mexp_h *, const char *s);

 static pid_t start_qemu_nbd (int nbd_local_port, const char *device);

+static int wait_qemu_nbd (int nbd_local_port, int timeout_seconds);

 static void cleanup_data_conns (struct data_conn *data_conns, size_t nr);

 static char *generate_libvirt_xml (struct config *, struct data_conn *);

 static const char *map_interface_to_network (struct config *, const char *interface);

@@ -156,6 +162,11 @@ start_conversion (struct config *config,

     if (data_conns[i].nbd_pid == 0)

       goto out;

+    /* Wait for qemu-nbd to listen */

+    if (wait_qemu_nbd (data_conns[i].nbd_local_port,

+                       WAIT_QEMU_NBD_TIMEOUT) == -1)

+      goto out;

+

 #if DEBUG_STDERR

     fprintf (stderr,

              "%s: data connection for %s: SSH remote port %d, local port %d\n",

@@ -371,6 +382,71 @@ start_qemu_nbd (int port, const char *device)

   return pid;

 }

+static int

+wait_qemu_nbd (int nbd_local_port, int timeout_seconds)

+{

+  int sockfd;

+  int result = -1;

+  struct sockaddr_in addr;

+  time_t start_t, now_t;

+  struct timeval timeout = { .tv_usec = 0 };

+  char magic[8]; /* NBDMAGIC */

+  size_t bytes_read = 0;

+  ssize_t recvd;

+

+  time (&start_t);

+

+  sockfd = socket (AF_INET, SOCK_STREAM, 0);

+  if (sockfd == -1) {

+    perror ("socket");

+    return -1;

+  }

+

+  memset (&addr, 0, sizeof addr);

+  addr.sin_family = AF_INET;

+  addr.sin_port = htons (nbd_local_port);

+  inet_pton (AF_INET, "localhost", &addr.sin_addr);

+

+  for (;;) {

+    time (&now_t);

+

+    if (now_t - start_t >= timeout_seconds) {

+      set_conversion_error ("waiting for qemu-nbd to start: connect: %m");

+      goto cleanup;

+    }

+

+    if (connect (sockfd, (struct sockaddr *) &addr, sizeof addr) == 0)

+      break;

+  }

+

+  time (&now_t);

+  timeout.tv_sec = (start_t + timeout_seconds) - now_t;

+  setsockopt (sockfd, SOL_SOCKET, SO_RCVTIMEO, &timeout, sizeof timeout);

+

+  do {

+    recvd = recv (sockfd, magic, sizeof magic - bytes_read, 0);

+

+    if (recvd == -1) {

+      set_conversion_error ("waiting for qemu-nbd to start: recv: %m");

+      goto cleanup;

+    }

+

+    bytes_read += recvd;

+  } while (bytes_read < sizeof magic);

+

+  if (memcmp (magic, "NBDMAGIC", sizeof magic) != 0) {

+    set_conversion_error ("waiting for qemu-nbd to start: "

+                          "'NBDMAGIC' was not received from qemu-nbd");

+    goto cleanup;

+  }

+

+  result = 0;

+cleanup:

+  close (sockfd);

+

+  return result;

+}

+

 static void

 cleanup_data_conns (struct data_conn *data_conns, size_t nr)

 {

-- 

1.8.3.1