[Libguestfs] [PATCH 1/5] p2v: Move NBD-related functions into a separate file.
Richard W.M. Jones
rjones at redhat.com
Fri Feb 3 14:21:14 UTC 2017
This is almost pure code motion, but I changed the name and prototype
of the function 'wait_nbd' to make its purpose clearer, and to remove
the unnecessary timeout setting (which is hard-coded).
---
p2v/Makefile.am | 1 +
p2v/conversion.c | 329 +------------------------------------
p2v/main.c | 86 +---------
p2v/nbd.c | 488 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
p2v/p2v.h | 16 +-
5 files changed, 506 insertions(+), 414 deletions(-)
create mode 100644 p2v/nbd.c
diff --git a/p2v/Makefile.am b/p2v/Makefile.am
index 0a2c2a8..93d7f47 100644
--- a/p2v/Makefile.am
+++ b/p2v/Makefile.am
@@ -81,6 +81,7 @@ virt_p2v_SOURCES = \
kernel.c \
kernel-cmdline.c \
main.c \
+ nbd.c \
p2v.h \
ssh.c \
utils.c \
diff --git a/p2v/conversion.c b/p2v/conversion.c
index aa9cd4c..44a3c58 100644
--- a/p2v/conversion.c
+++ b/p2v/conversion.c
@@ -82,21 +82,14 @@ xmlBufferDetach (xmlBufferPtr buf)
}
#endif
-/* How long to wait for the NBD server to start (seconds). */
-#define WAIT_NBD_TIMEOUT 10
-
/* Data per NBD connection / physical disk. */
struct data_conn {
mexp_h *h; /* miniexpect handle to ssh */
- pid_t nbd_pid; /* qemu pid */
+ pid_t nbd_pid; /* NBD server PID */
int nbd_local_port; /* local NBD port on physical machine */
int nbd_remote_port; /* remote NBD port on conversion server */
};
-static pid_t start_nbd (int nbd_local_port, const char *device);
-static pid_t start_qemu_nbd (int nbd_local_port, const char *device);
-static pid_t start_nbdkit (int nbd_local_port, const char *device);
-static int wait_nbd (int nbd_local_port, int timeout_seconds);
static void cleanup_data_conns (struct data_conn *data_conns, size_t nr);
static void generate_name (struct config *, const char *filename);
static void generate_libvirt_xml (struct config *, struct data_conn *, const char *filename);
@@ -288,14 +281,17 @@ start_conversion (struct config *config,
/* Start NBD server listening on the given port number. */
data_conns[i].nbd_pid =
- start_nbd (data_conns[i].nbd_local_port, device);
- if (data_conns[i].nbd_pid == 0)
+ start_nbd_server (data_conns[i].nbd_local_port, device);
+ if (data_conns[i].nbd_pid == 0) {
+ set_conversion_error ("NBD server error: %s", get_nbd_error ());
goto out;
+ }
- /* Wait for NBD server to listen */
- if (wait_nbd (data_conns[i].nbd_local_port,
- WAIT_NBD_TIMEOUT) == -1)
+ /* Wait for NBD server to start up and listen. */
+ if (wait_for_nbd_server_to_start (data_conns[i].nbd_local_port) == -1) {
+ set_conversion_error ("NBD server error: %s", get_nbd_error ());
goto out;
+ }
}
/* Create a remote directory name which will be used for libvirt
@@ -465,313 +461,6 @@ cancel_conversion (void)
set_cancel_requested (1);
}
-/**
- * Start the first server found in the C<nbd_servers> list.
- *
- * We previously tested all NBD servers (see C<test_nbd_servers>) so
- * we only need to run the first server in the list.
- *
- * Returns the process ID (E<gt> 0) or C<0> if there is an error.
- */
-static pid_t
-start_nbd (int port, const char *device)
-{
- size_t i;
-
- for (i = 0; i < NR_NBD_SERVERS; ++i) {
- switch (nbd_servers[i]) {
- case NO_SERVER:
- /* ignore */
- break;
-
- case QEMU_NBD:
- return start_qemu_nbd (port, device);
-
- case NBDKIT:
- return start_nbdkit (port, device);
-
- default:
- abort ();
- }
- }
-
- /* This should never happen because of the checks in
- * test_nbd_servers.
- */
- abort ();
-}
-
-/**
- * Start a local L<qemu-nbd(1)> process.
- *
- * Returns the process ID (E<gt> 0) or C<0> if there is an error.
- */
-static pid_t
-start_qemu_nbd (int port, const char *device)
-{
- pid_t pid;
- char port_str[64];
-
-#if DEBUG_STDERR
- fprintf (stderr, "starting qemu-nbd for %s on port %d\n", device, port);
-#endif
-
- snprintf (port_str, sizeof port_str, "%d", port);
-
- pid = fork ();
- if (pid == -1) {
- set_conversion_error ("fork: %m");
- return 0;
- }
-
- if (pid == 0) { /* Child. */
- close (0);
- open ("/dev/null", O_RDONLY);
-
- execlp ("qemu-nbd",
- "qemu-nbd",
- "-r", /* readonly (vital!) */
- "-p", port_str, /* listening port */
- "-t", /* persistent */
- "-f", "raw", /* force raw format */
- "-b", "localhost", /* listen only on loopback interface */
- "--cache=unsafe", /* use unsafe caching for speed */
- device, /* a device like /dev/sda */
- NULL);
- perror ("qemu-nbd");
- _exit (EXIT_FAILURE);
- }
-
- /* Parent. */
- return pid;
-}
-
-/**
- * Start a local L<nbdkit(1)> process using the
- * L<nbdkit-file-plugin(1)>.
- *
- * Returns the process ID (E<gt> 0) or C<0> if there is an error.
- */
-static pid_t
-start_nbdkit (int port, const char *device)
-{
- pid_t pid;
- char port_str[64];
- CLEANUP_FREE char *file_str = NULL;
-
-#if DEBUG_STDERR
- fprintf (stderr, "starting nbdkit for %s on port %d\n", device, port);
-#endif
-
- snprintf (port_str, sizeof port_str, "%d", port);
-
- if (asprintf (&file_str, "file=%s", device) == -1)
- error (EXIT_FAILURE, errno, "asprintf");
-
- pid = fork ();
- if (pid == -1) {
- set_conversion_error ("fork: %m");
- return 0;
- }
-
- if (pid == 0) { /* Child. */
- close (0);
- open ("/dev/null", O_RDONLY);
-
- execlp ("nbdkit",
- "nbdkit",
- "-r", /* readonly (vital!) */
- "-p", port_str, /* listening port */
- "-i", "localhost", /* listen only on loopback interface */
- "-f", /* don't fork */
- "file", /* file plugin */
- file_str, /* a device like file=/dev/sda */
- NULL);
- perror ("nbdkit");
- _exit (EXIT_FAILURE);
- }
-
- /* Parent. */
- return pid;
-}
-
-static int bind_source_port (int sockfd, int family, int source_port);
-
-/**
- * Connect to C<hostname:dest_port>, resolving the address using
- * L<getaddrinfo(3)>.
- *
- * This also sets the source port of the connection to the first free
- * port number E<ge> C<source_port>.
- *
- * This may involve multiple connections - to IPv4 and IPv6 for
- * instance.
- */
-static int
-connect_with_source_port (const char *hostname, int dest_port, int source_port)
-{
- struct addrinfo hints;
- struct addrinfo *results, *rp;
- char dest_port_str[16];
- int r, sockfd = -1;
- int reuseaddr = 1;
-
- snprintf (dest_port_str, sizeof dest_port_str, "%d", dest_port);
-
- memset (&hints, 0, sizeof hints);
- hints.ai_family = AF_UNSPEC; /* allow IPv4 or IPv6 */
- hints.ai_socktype = SOCK_STREAM;
- hints.ai_flags = AI_NUMERICSERV; /* numeric dest port number */
- hints.ai_protocol = 0; /* any protocol */
-
- r = getaddrinfo (hostname, dest_port_str, &hints, &results);
- if (r != 0) {
- set_conversion_error ("getaddrinfo: %s/%s: %s",
- hostname, dest_port_str, gai_strerror (r));
- return -1;
- }
-
- for (rp = results; rp != NULL; rp = rp->ai_next) {
- sockfd = socket (rp->ai_family, rp->ai_socktype, rp->ai_protocol);
- if (sockfd == -1)
- continue;
-
- /* If we run p2v repeatedly (say, running the tests in a loop),
- * there's a decent chance we'll end up trying to bind() to a port
- * that is in TIME_WAIT from a prior run. Handle that gracefully
- * with SO_REUSEADDR.
- */
- if (setsockopt (sockfd, SOL_SOCKET, SO_REUSEADDR,
- &reuseaddr, sizeof reuseaddr) == -1)
- perror ("warning: setsockopt");
-
- /* Need to bind the source port. */
- if (bind_source_port (sockfd, rp->ai_family, source_port) == -1) {
- close (sockfd);
- sockfd = -1;
- continue;
- }
-
- /* Connect. */
- if (connect (sockfd, rp->ai_addr, rp->ai_addrlen) == -1) {
- set_conversion_error ("waiting for NBD server to start: "
- "connect to %s/%s: %m",
- hostname, dest_port_str);
- close (sockfd);
- sockfd = -1;
- continue;
- }
-
- break;
- }
-
- freeaddrinfo (results);
- return sockfd;
-}
-
-static int
-bind_source_port (int sockfd, int family, int source_port)
-{
- struct addrinfo hints;
- struct addrinfo *results, *rp;
- char source_port_str[16];
- int r;
-
- snprintf (source_port_str, sizeof source_port_str, "%d", source_port);
-
- memset (&hints, 0, sizeof (hints));
- hints.ai_family = family;
- hints.ai_socktype = SOCK_STREAM;
- hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV; /* numeric port number */
- hints.ai_protocol = 0; /* any protocol */
-
- r = getaddrinfo ("localhost", source_port_str, &hints, &results);
- if (r != 0) {
- set_conversion_error ("getaddrinfo (bind): localhost/%s: %s",
- source_port_str, gai_strerror (r));
- return -1;
- }
-
- for (rp = results; rp != NULL; rp = rp->ai_next) {
- if (bind (sockfd, rp->ai_addr, rp->ai_addrlen) == 0)
- goto bound;
- }
-
- set_conversion_error ("waiting for NBD server to start: "
- "bind to source port %d: %m",
- source_port);
- freeaddrinfo (results);
- return -1;
-
- bound:
- freeaddrinfo (results);
- return 0;
-}
-
-static int
-wait_nbd (int nbd_local_port, int timeout_seconds)
-{
- int sockfd = -1;
- int result = -1;
- time_t start_t, now_t;
- struct timespec half_sec = { .tv_sec = 0, .tv_nsec = 500000000 };
- struct timeval timeout = { .tv_usec = 0 };
- char magic[8]; /* NBDMAGIC */
- size_t bytes_read = 0;
- ssize_t recvd;
-
- time (&start_t);
-
- for (;;) {
- time (&now_t);
-
- if (now_t - start_t >= timeout_seconds)
- goto cleanup;
-
- /* Source port for probing NBD server should be one greater than
- * nbd_local_port. It's not guaranteed to always bind to this
- * port, but it will hint the kernel to start there and try
- * incrementally higher ports if needed. This avoids the case
- * where the kernel selects nbd_local_port as our source port, and
- * we immediately connect to ourself. See:
- * https://bugzilla.redhat.com/show_bug.cgi?id=1167774#c9
- */
- sockfd = connect_with_source_port ("localhost", nbd_local_port,
- nbd_local_port+1);
- if (sockfd >= 0)
- break;
-
- nanosleep (&half_sec, NULL);
- }
-
- 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 NBD server 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 NBD server to start: "
- "'NBDMAGIC' was not received from NBD server");
- goto cleanup;
- }
-
- result = 0;
- cleanup:
- close (sockfd);
-
- return result;
-}
-
static void
cleanup_data_conns (struct data_conn *data_conns, size_t nr)
{
diff --git a/p2v/main.c b/p2v/main.c
index f616b4f..d1eece6 100644
--- a/p2v/main.c
+++ b/p2v/main.c
@@ -54,7 +54,6 @@ int is_iso_environment = 0;
int nbd_local_port;
int feature_colours_option = 0;
int force_colour = 0;
-enum nbd_server nbd_servers[NR_NBD_SERVERS] = { QEMU_NBD, NBDKIT };
static const char *test_disk = NULL;
static void udevadm_settle (void);
@@ -62,7 +61,6 @@ static void set_config_defaults (struct config *config);
static void find_all_disks (void);
static void find_all_interfaces (void);
static int cpuinfo_flags (void);
-static void test_nbd_servers (void);
enum { HELP_OPTION = CHAR_MAX + 1 };
static const char options[] = "Vv";
@@ -133,35 +131,6 @@ display_long_options (const struct option *long_options)
exit (EXIT_SUCCESS);
}
-static void
-set_nbd_servers (const char *opt)
-{
- size_t i;
- CLEANUP_FREE_STRING_LIST char **strs
- = guestfs_int_split_string (',', opt);
-
- if (strs == NULL)
- error (EXIT_FAILURE, errno, _("malloc"));
-
- if (strs[0] == NULL)
- error (EXIT_FAILURE, 0, _("--nbd option cannot be empty"));
-
- for (i = 0; strs[i] != NULL; ++i) {
- if (i >= NR_NBD_SERVERS)
- error (EXIT_FAILURE, 0, _("too many --nbd servers"));
-
- if (STREQ (strs[i], "qemu-nbd") || STREQ (strs[i], "qemu"))
- nbd_servers[i] = QEMU_NBD;
- else if (STREQ (strs[i], "nbdkit"))
- nbd_servers[i] = NBDKIT;
- else
- error (EXIT_FAILURE, 0, _("--nbd: unknown server: %s"), strs[i]);
- }
-
- for (; i < NR_NBD_SERVERS; ++i)
- nbd_servers[i] = NO_SERVER;
-}
-
int
main (int argc, char *argv[])
{
@@ -214,7 +183,7 @@ main (int argc, char *argv[])
is_iso_environment = 1;
}
else if (STREQ (long_options[option_index].name, "nbd")) {
- set_nbd_servers (optarg);
+ set_nbd_option (optarg); /* in nbd.c */
}
else if (STREQ (long_options[option_index].name, "test-disk")) {
if (test_disk != NULL)
@@ -309,59 +278,6 @@ udevadm_settle (void)
ignore_value (system ("udevadm settle"));
}
-/* Test the nbd_servers[] array to see which servers are actually
- * installed and appear to be working. If a server is not installed
- * we set the corresponding nbd_servers[i] = NO_SERVER.
- */
-static void
-test_nbd_servers (void)
-{
- size_t i;
- int r;
-
- for (i = 0; i < NR_NBD_SERVERS; ++i) {
- switch (nbd_servers[i]) {
- case NO_SERVER:
- /* ignore entry */
- break;
-
- case QEMU_NBD:
- r = system ("qemu-nbd --version"
-#ifndef DEBUG_STDERR
- " >/dev/null 2>&1"
-#endif
- );
- if (r != 0)
- nbd_servers[i] = NO_SERVER;
- break;
-
- case NBDKIT:
- r = system ("nbdkit file --version"
-#ifndef DEBUG_STDERR
- " >/dev/null 2>&1"
-#endif
- );
- if (r != 0)
- nbd_servers[i] = NO_SERVER;
- break;
-
- default:
- abort ();
- }
- }
-
- for (i = 0; i < NR_NBD_SERVERS; ++i)
- if (nbd_servers[i] != NO_SERVER)
- return;
-
- /* If we reach here, there are no servers left, so we have to exit. */
- fprintf (stderr,
- _("%s: no working NBD server was found, cannot continue.\n"
- "Please check the --nbd option in the virt-p2v(1) man page.\n"),
- getprogname ());
- exit (EXIT_FAILURE);
-}
-
static void
set_config_defaults (struct config *config)
{
diff --git a/p2v/nbd.c b/p2v/nbd.c
new file mode 100644
index 0000000..519774f
--- /dev/null
+++ b/p2v/nbd.c
@@ -0,0 +1,488 @@
+/* virt-p2v
+ * Copyright (C) 2009-2017 Red Hat Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+/**
+ * This file handles the virt-p2v I<--nbd> command line option
+ * and running either L<qemu-nbd(8)> or L<nbdkit(1)>.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <inttypes.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <time.h>
+#include <netdb.h>
+#include <errno.h>
+#include <error.h>
+#include <libintl.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+
+#include "getprogname.h"
+
+#include "p2v.h"
+
+/* How long to wait for the NBD server to start (seconds). */
+#define WAIT_NBD_TIMEOUT 10
+
+/* virt-p2v --nbd option. */
+enum nbd_server {
+ NO_SERVER = 0,
+ QEMU_NBD = 1,
+ NBDKIT = 2,
+#define NR_NBD_SERVERS 2
+};
+static enum nbd_server nbd_servers[NR_NBD_SERVERS] = { QEMU_NBD, NBDKIT };
+
+static pid_t start_qemu_nbd (int nbd_local_port, const char *device);
+static pid_t start_nbdkit (int nbd_local_port, const char *device);
+static int connect_with_source_port (const char *hostname, int dest_port, int source_port);
+static int bind_source_port (int sockfd, int family, int source_port);
+
+static char *nbd_error;
+
+static void set_nbd_error (const char *fs, ...)
+ __attribute__((format(printf,1,2)));
+
+static void
+set_nbd_error (const char *fs, ...)
+{
+ va_list args;
+ char *msg;
+ int len;
+
+ va_start (args, fs);
+ len = vasprintf (&msg, fs, args);
+ va_end (args);
+
+ if (len < 0)
+ error (EXIT_FAILURE, errno,
+ "vasprintf (original error format string: %s)", fs);
+
+ free (nbd_error);
+ nbd_error = msg;
+}
+
+const char *
+get_nbd_error (void)
+{
+ return nbd_error;
+}
+
+/**
+ * The main program calls this to set the I<--nbd> option.
+ */
+void
+set_nbd_option (const char *opt)
+{
+ size_t i;
+ CLEANUP_FREE_STRING_LIST char **strs
+ = guestfs_int_split_string (',', opt);
+
+ if (strs == NULL)
+ error (EXIT_FAILURE, errno, _("malloc"));
+
+ if (strs[0] == NULL)
+ error (EXIT_FAILURE, 0, _("--nbd option cannot be empty"));
+
+ for (i = 0; strs[i] != NULL; ++i) {
+ if (i >= NR_NBD_SERVERS)
+ error (EXIT_FAILURE, 0, _("too many --nbd servers"));
+
+ if (STREQ (strs[i], "qemu-nbd") || STREQ (strs[i], "qemu"))
+ nbd_servers[i] = QEMU_NBD;
+ else if (STREQ (strs[i], "nbdkit"))
+ nbd_servers[i] = NBDKIT;
+ else
+ error (EXIT_FAILURE, 0, _("--nbd: unknown server: %s"), strs[i]);
+ }
+
+ for (; i < NR_NBD_SERVERS; ++i)
+ nbd_servers[i] = NO_SERVER;
+}
+
+/**
+ * Test the I<--nbd> option (or built-in default list) to see which
+ * servers are actually installed and appear to be working.
+ *
+ * If a server is not installed we set the corresponding
+ * C<nbd_servers[i] = NO_SERVER>.
+ */
+void
+test_nbd_servers (void)
+{
+ size_t i;
+ int r;
+
+ for (i = 0; i < NR_NBD_SERVERS; ++i) {
+ switch (nbd_servers[i]) {
+ case NO_SERVER:
+ /* ignore entry */
+ break;
+
+ case QEMU_NBD:
+ r = system ("qemu-nbd --version"
+#ifndef DEBUG_STDERR
+ " >/dev/null 2>&1"
+#endif
+ );
+ if (r != 0)
+ nbd_servers[i] = NO_SERVER;
+ break;
+
+ case NBDKIT:
+ r = system ("nbdkit file --version"
+#ifndef DEBUG_STDERR
+ " >/dev/null 2>&1"
+#endif
+ );
+ if (r != 0)
+ nbd_servers[i] = NO_SERVER;
+ break;
+
+ default:
+ abort ();
+ }
+ }
+
+ for (i = 0; i < NR_NBD_SERVERS; ++i)
+ if (nbd_servers[i] != NO_SERVER)
+ return;
+
+ /* If we reach here, there are no servers left, so we have to exit. */
+ fprintf (stderr,
+ _("%s: no working NBD server was found, cannot continue.\n"
+ "Please check the --nbd option in the virt-p2v(1) man page.\n"),
+ getprogname ());
+ exit (EXIT_FAILURE);
+}
+
+/**
+ * Start the first server found in the C<nbd_servers> list.
+ *
+ * We previously tested all NBD servers (see C<test_nbd_servers>) so
+ * we only need to run the first server in the list.
+ *
+ * Returns the process ID (E<gt> 0) or C<0> if there is an error.
+ */
+pid_t
+start_nbd_server (int port, const char *device)
+{
+ size_t i;
+
+ for (i = 0; i < NR_NBD_SERVERS; ++i) {
+ switch (nbd_servers[i]) {
+ case NO_SERVER:
+ /* ignore */
+ break;
+
+ case QEMU_NBD:
+ return start_qemu_nbd (port, device);
+
+ case NBDKIT:
+ return start_nbdkit (port, device);
+
+ default:
+ abort ();
+ }
+ }
+
+ /* This should never happen because of the checks in
+ * test_nbd_servers.
+ */
+ abort ();
+}
+
+/**
+ * Start a local L<qemu-nbd(1)> process.
+ *
+ * Returns the process ID (E<gt> 0) or C<0> if there is an error.
+ */
+static pid_t
+start_qemu_nbd (int port, const char *device)
+{
+ pid_t pid;
+ char port_str[64];
+
+#if DEBUG_STDERR
+ fprintf (stderr, "starting qemu-nbd for %s on port %d\n", device, port);
+#endif
+
+ snprintf (port_str, sizeof port_str, "%d", port);
+
+ pid = fork ();
+ if (pid == -1) {
+ set_nbd_error ("fork: %m");
+ return 0;
+ }
+
+ if (pid == 0) { /* Child. */
+ close (0);
+ open ("/dev/null", O_RDONLY);
+
+ execlp ("qemu-nbd",
+ "qemu-nbd",
+ "-r", /* readonly (vital!) */
+ "-p", port_str, /* listening port */
+ "-t", /* persistent */
+ "-f", "raw", /* force raw format */
+ "-b", "localhost", /* listen only on loopback interface */
+ "--cache=unsafe", /* use unsafe caching for speed */
+ device, /* a device like /dev/sda */
+ NULL);
+ perror ("qemu-nbd");
+ _exit (EXIT_FAILURE);
+ }
+
+ /* Parent. */
+ return pid;
+}
+
+/**
+ * Start a local L<nbdkit(1)> process using the
+ * L<nbdkit-file-plugin(1)>.
+ *
+ * Returns the process ID (E<gt> 0) or C<0> if there is an error.
+ */
+static pid_t
+start_nbdkit (int port, const char *device)
+{
+ pid_t pid;
+ char port_str[64];
+ CLEANUP_FREE char *file_str = NULL;
+
+#if DEBUG_STDERR
+ fprintf (stderr, "starting nbdkit for %s on port %d\n", device, port);
+#endif
+
+ snprintf (port_str, sizeof port_str, "%d", port);
+
+ if (asprintf (&file_str, "file=%s", device) == -1)
+ error (EXIT_FAILURE, errno, "asprintf");
+
+ pid = fork ();
+ if (pid == -1) {
+ set_nbd_error ("fork: %m");
+ return 0;
+ }
+
+ if (pid == 0) { /* Child. */
+ close (0);
+ open ("/dev/null", O_RDONLY);
+
+ execlp ("nbdkit",
+ "nbdkit",
+ "-r", /* readonly (vital!) */
+ "-p", port_str, /* listening port */
+ "-i", "localhost", /* listen only on loopback interface */
+ "-f", /* don't fork */
+ "file", /* file plugin */
+ file_str, /* a device like file=/dev/sda */
+ NULL);
+ perror ("nbdkit");
+ _exit (EXIT_FAILURE);
+ }
+
+ /* Parent. */
+ return pid;
+}
+
+/**
+ * Wait for a local NBD server to start and be listening for
+ * connections.
+ */
+int
+wait_for_nbd_server_to_start (int nbd_local_port)
+{
+ int sockfd = -1;
+ int result = -1;
+ time_t start_t, now_t;
+ struct timespec half_sec = { .tv_sec = 0, .tv_nsec = 500000000 };
+ struct timeval timeout = { .tv_usec = 0 };
+ char magic[8]; /* NBDMAGIC */
+ size_t bytes_read = 0;
+ ssize_t recvd;
+
+ time (&start_t);
+
+ for (;;) {
+ time (&now_t);
+
+ if (now_t - start_t >= WAIT_NBD_TIMEOUT) {
+ set_nbd_error ("timed out waiting for NBD server to start");
+ goto cleanup;
+ }
+
+ /* Source port for probing NBD server should be one greater than
+ * nbd_local_port. It's not guaranteed to always bind to this
+ * port, but it will hint the kernel to start there and try
+ * incrementally higher ports if needed. This avoids the case
+ * where the kernel selects nbd_local_port as our source port, and
+ * we immediately connect to ourself. See:
+ * https://bugzilla.redhat.com/show_bug.cgi?id=1167774#c9
+ */
+ sockfd = connect_with_source_port ("localhost", nbd_local_port,
+ nbd_local_port+1);
+ if (sockfd >= 0)
+ break;
+
+ nanosleep (&half_sec, NULL);
+ }
+
+ time (&now_t);
+ timeout.tv_sec = (start_t + WAIT_NBD_TIMEOUT) - 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_nbd_error ("waiting for NBD server to start: recv: %m");
+ goto cleanup;
+ }
+
+ bytes_read += recvd;
+ } while (bytes_read < sizeof magic);
+
+ if (memcmp (magic, "NBDMAGIC", sizeof magic) != 0) {
+ set_nbd_error ("waiting for NBD server to start: "
+ "'NBDMAGIC' was not received from NBD server");
+ goto cleanup;
+ }
+
+ result = 0;
+ cleanup:
+ close (sockfd);
+
+ return result;
+}
+
+/**
+ * Connect to C<hostname:dest_port>, resolving the address using
+ * L<getaddrinfo(3)>.
+ *
+ * This also sets the source port of the connection to the first free
+ * port number E<ge> C<source_port>.
+ *
+ * This may involve multiple connections - to IPv4 and IPv6 for
+ * instance.
+ */
+static int
+connect_with_source_port (const char *hostname, int dest_port, int source_port)
+{
+ struct addrinfo hints;
+ struct addrinfo *results, *rp;
+ char dest_port_str[16];
+ int r, sockfd = -1;
+ int reuseaddr = 1;
+
+ snprintf (dest_port_str, sizeof dest_port_str, "%d", dest_port);
+
+ memset (&hints, 0, sizeof hints);
+ hints.ai_family = AF_UNSPEC; /* allow IPv4 or IPv6 */
+ hints.ai_socktype = SOCK_STREAM;
+ hints.ai_flags = AI_NUMERICSERV; /* numeric dest port number */
+ hints.ai_protocol = 0; /* any protocol */
+
+ r = getaddrinfo (hostname, dest_port_str, &hints, &results);
+ if (r != 0) {
+ set_nbd_error ("getaddrinfo: %s/%s: %s",
+ hostname, dest_port_str, gai_strerror (r));
+ return -1;
+ }
+
+ for (rp = results; rp != NULL; rp = rp->ai_next) {
+ sockfd = socket (rp->ai_family, rp->ai_socktype, rp->ai_protocol);
+ if (sockfd == -1)
+ continue;
+
+ /* If we run p2v repeatedly (say, running the tests in a loop),
+ * there's a decent chance we'll end up trying to bind() to a port
+ * that is in TIME_WAIT from a prior run. Handle that gracefully
+ * with SO_REUSEADDR.
+ */
+ if (setsockopt (sockfd, SOL_SOCKET, SO_REUSEADDR,
+ &reuseaddr, sizeof reuseaddr) == -1)
+ perror ("warning: setsockopt");
+
+ /* Need to bind the source port. */
+ if (bind_source_port (sockfd, rp->ai_family, source_port) == -1) {
+ close (sockfd);
+ sockfd = -1;
+ continue;
+ }
+
+ /* Connect. */
+ if (connect (sockfd, rp->ai_addr, rp->ai_addrlen) == -1) {
+ set_nbd_error ("waiting for NBD server to start: "
+ "connect to %s/%s: %m",
+ hostname, dest_port_str);
+ close (sockfd);
+ sockfd = -1;
+ continue;
+ }
+
+ break;
+ }
+
+ freeaddrinfo (results);
+ return sockfd;
+}
+
+static int
+bind_source_port (int sockfd, int family, int source_port)
+{
+ struct addrinfo hints;
+ struct addrinfo *results, *rp;
+ char source_port_str[16];
+ int r;
+
+ snprintf (source_port_str, sizeof source_port_str, "%d", source_port);
+
+ memset (&hints, 0, sizeof (hints));
+ hints.ai_family = family;
+ hints.ai_socktype = SOCK_STREAM;
+ hints.ai_flags = AI_PASSIVE | AI_NUMERICSERV; /* numeric port number */
+ hints.ai_protocol = 0; /* any protocol */
+
+ r = getaddrinfo ("localhost", source_port_str, &hints, &results);
+ if (r != 0) {
+ set_nbd_error ("getaddrinfo (bind): localhost/%s: %s",
+ source_port_str, gai_strerror (r));
+ return -1;
+ }
+
+ for (rp = results; rp != NULL; rp = rp->ai_next) {
+ if (bind (sockfd, rp->ai_addr, rp->ai_addrlen) == 0)
+ goto bound;
+ }
+
+ set_nbd_error ("waiting for NBD server to start: "
+ "bind to source port %d: %m",
+ source_port);
+ freeaddrinfo (results);
+ return -1;
+
+ bound:
+ freeaddrinfo (results);
+ return 0;
+}
diff --git a/p2v/p2v.h b/p2v/p2v.h
index d805aaf..800862d 100644
--- a/p2v/p2v.h
+++ b/p2v/p2v.h
@@ -63,15 +63,6 @@ extern int feature_colours_option;
/* virt-p2v --colours option (used by ansi_* macros). */
extern int force_colour;
-/* virt-p2v --nbd option. */
-enum nbd_server {
- NO_SERVER = 0,
- QEMU_NBD = 1,
- NBDKIT = 2,
-#define NR_NBD_SERVERS 2
-};
-extern enum nbd_server nbd_servers[NR_NBD_SERVERS];
-
/* config.c */
struct config {
char *server;
@@ -144,6 +135,13 @@ extern mexp_h *start_remote_connection (struct config *, const char *remote_dir)
extern const char *get_ssh_error (void);
extern int scp_file (struct config *config, const char *localfile, const char *remotefile);
+/* nbd.c */
+extern void set_nbd_option (const char *opt);
+extern void test_nbd_servers (void);
+extern pid_t start_nbd_server (int nbd_local_port, const char *device);
+extern int wait_for_nbd_server_to_start (int nbd_local_port);
+const char *get_nbd_error (void);
+
/* utils.c */
extern uint64_t get_blockdev_size (const char *dev);
extern char *get_blockdev_model (const char *dev);
--
2.9.3
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