From 11ef6d48abcfc90c0a6e795a067547c289e883d6 Mon Sep 17 00:00:00 2001

From: "Richard W.M. Jones" <rjones@redhat.com>

Date: Sat, 18 Jun 2016 14:44:24 +0100

Subject: [PATCH] p2v: Use a wrapper script instead of long virt-v2v command

 lne.

Instead of constructing and directly executing a long virt-v2v command

line, build a wrapper script with the same command line and send it to

the remote server (stored in /<remote_dir>/virt-v2v-wrapper.sh).

This will make it a bit easier to construct more complex virt-v2v

wrappers.

Note this commit on its own is a simple refactoring and does not

change any functionality.

(cherry picked from commit 514893b68b6180b3adc5bb762e9d67054a9a7f63)

---

 p2v/conversion.c | 203 +++++++++++++++++++++++++++++++++----------------------

 p2v/p2v.h        |   2 +-

 p2v/ssh.c        |  25 ++++++-

 p2v/virt-p2v.pod |  17 +++--

 4 files changed, 159 insertions(+), 88 deletions(-)

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

index 5265a76..decaf7c 100644

--- a/p2v/conversion.c

+++ b/p2v/conversion.c

@@ -27,6 +27,7 @@

 #include <unistd.h>

 #include <time.h>

 #include <errno.h>

+#include <error.h>

 #include <locale.h>

 #include <libintl.h>

 #include <netdb.h>

@@ -78,11 +79,11 @@ struct data_conn {

   int nbd_remote_port;      /* remote NBD port on conversion server */

 };

-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 char *generate_wrapper_script (struct config *, const char *remote_dir);

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

 static char *conversion_error;

@@ -168,7 +169,8 @@ start_conversion (struct config *config,

   size_t i, len;

   const size_t nr_disks = guestfs_int_count_strings (config->disks);

   struct data_conn data_conns[nr_disks];

-  CLEANUP_FREE char *remote_dir = NULL, *libvirt_xml = NULL;

+  CLEANUP_FREE char *remote_dir = NULL, *libvirt_xml = NULL,

+    *wrapper_script = NULL;

   time_t now;

   struct tm tm;

   mexp_h *control_h = NULL;

@@ -276,7 +278,18 @@ start_conversion (struct config *config,

     goto out;

 #if DEBUG_STDERR

-  fprintf (stderr, "%s: libvirt XML:\n%s", guestfs_int_program_name, libvirt_xml);

+  fprintf (stderr, "%s: libvirt XML:\n%s",

+           guestfs_int_program_name, libvirt_xml);

+#endif

+

+  /* Generate the virt-v2v wrapper script. */

+  wrapper_script = generate_wrapper_script (config, remote_dir);

+  if (wrapper_script == NULL)

+    goto out;

+

+#if DEBUG_STDERR

+  fprintf (stderr, "%s: wrapper script:\n%s",

+           guestfs_int_program_name, wrapper_script);

 #endif

   /* Get the output from the 'dmesg' command.  We will store this

@@ -305,7 +318,9 @@ start_conversion (struct config *config,

   if (notify_ui)

     notify_ui (NOTIFY_STATUS, _("Setting up the control connection ..."));

-  control_h = start_remote_connection (config, remote_dir, libvirt_xml, dmesg);

+  control_h = start_remote_connection (config,

+                                       remote_dir, libvirt_xml,

+                                       wrapper_script, dmesg);

   if (control_h == NULL) {

     const char *err = get_ssh_error ();

@@ -317,66 +332,18 @@ start_conversion (struct config *config,

   if (notify_ui)

     notify_ui (NOTIFY_STATUS, _("Doing conversion ..."));

-  /* Build the virt-v2v command up in pieces to make the quoting

-   * slightly more sane.

-   */

-  if (mexp_printf (control_h, "( %s virt-v2v%s%s -i libvirtxml",

-                   config->sudo ? "sudo -n " : "",

-                   config->verbose ? " -v -x" : "",

-                   feature_colours_option ? " --colours" : "") == -1) {

-  printf_fail:

-    set_conversion_error ("mexp_printf: virt-v2v command: %m");

+  if (mexp_printf (control_h,

+                   /* To simplify things in the wrapper script, it

+                    * writes virt-v2v's exit status to

+                    * /remote_dir/status, and here we read that and

+                    * exit the ssh shell with the same status.

+                    */

+                   "%s/virt-v2v-wrapper.sh; "

+                   "exit $(< %s/status)\n",

+                   remote_dir, remote_dir) == -1) {

+    set_conversion_error ("mexp_printf: virt-v2v: %m");

     goto out;

   }

-  if (config->output) {         /* -o */

-    if (mexp_printf (control_h, " -o ") == -1)

-      goto printf_fail;

-    if (send_quoted (control_h, config->output) == -1)

-      goto printf_fail;

-  }

-  switch (config->output_allocation) { /* -oa */

-  case OUTPUT_ALLOCATION_NONE:

-    /* nothing */

-    break;

-  case OUTPUT_ALLOCATION_SPARSE:

-    if (mexp_printf (control_h, " -oa sparse") == -1)

-      goto printf_fail;

-    break;

-  case OUTPUT_ALLOCATION_PREALLOCATED:

-    if (mexp_printf (control_h, " -oa preallocated") == -1)

-      goto printf_fail;

-    break;

-  default:

-    abort ();

-  }

-  if (config->output_format) {  /* -of */

-    if (mexp_printf (control_h, " -of ") == -1)

-      goto printf_fail;

-    if (send_quoted (control_h, config->output_format) == -1)

-      goto printf_fail;

-  }

-  if (config->output_storage) { /* -os */

-    if (mexp_printf (control_h, " -os ") == -1)

-      goto printf_fail;

-    if (send_quoted (control_h, config->output_storage) == -1)

-      goto printf_fail;

-  }

-  if (mexp_printf (control_h, " --root first") == -1)

-    goto printf_fail;

-  if (mexp_printf (control_h, " %s/physical.xml", remote_dir) == -1)

-    goto printf_fail;

-  /* no stdin, and send stdout and stderr to the same place */

-  if (mexp_printf (control_h, " </dev/null 2>&1") == -1)

-    goto printf_fail;

-  if (mexp_printf (control_h, " ; echo $? > %s/status", remote_dir) == -1)

-    goto printf_fail;

-  if (mexp_printf (control_h, " ) | tee %s/virt-v2v-conversion-log.txt",

-                   remote_dir) == -1)

-    goto printf_fail;

-  if (mexp_printf (control_h, "; exit $(< %s/status)", remote_dir) == -1)

-    goto printf_fail;

-  if (mexp_printf (control_h, "\n") == -1)

-    goto printf_fail;

   /* Read output from the virt-v2v process and echo it through the

    * notify function, until virt-v2v closes the connection.

@@ -443,26 +410,6 @@ cancel_conversion (void)

   set_cancel_requested (1);

 }

-/* Send a shell-quoted string to remote. */

-static int

-send_quoted (mexp_h *h, const char *s)

-{

-  if (mexp_printf (h, "\"") == -1)

-    return -1;

-  while (*s) {

-    if (*s == '$' || *s == '`' || *s == '\\' || *s == '"') {

-      if (mexp_printf (h, "\\") == -1)

-        return -1;

-    }

-    if (mexp_printf (h, "%c", *s) == -1)

-      return -1;

-    ++s;

-  }

-  if (mexp_printf (h, "\"") == -1)

-    return -1;

-  return 0;

-}

-

 /* Note: returns process ID (> 0) or 0 if there is an error. */

 static pid_t

 start_qemu_nbd (int port, const char *device)

@@ -980,3 +927,95 @@ map_interface_to_network (struct config *config, const char *interface)

   /* No mapping found. */

   return "default";

 }

+

+/**

+ * Print a shell-quoted string on C<fp>.

+ */

+static void

+print_quoted (FILE *fp, const char *s)

+{

+  fprintf (fp, "\"");

+  while (*s) {

+    if (*s == '$' || *s == '`' || *s == '\\' || *s == '"')

+      fprintf (fp, "\\");

+    fprintf (fp, "%c", *s);

+    ++s;

+  }

+  fprintf (fp, "\"");

+}

+

+/**

+ * Construct the virt-v2v wrapper script.

+ *

+ * This will be sent to the remote server, and is easier than trying

+ * to "type" a long and complex single command line into the ssh

+ * connection when we start the conversion.

+ */

+static char *

+generate_wrapper_script (struct config *config, const char *remote_dir)

+{

+  FILE *fp;

+  char *output = NULL;

+  size_t output_len = 0;

+

+  fp = open_memstream (&output, &output_len);

+  if (fp == NULL)

+    error (EXIT_FAILURE, errno, "open_memstream");

+

+  fprintf (fp, "#!/bin/sh -\n");

+  fprintf (fp, "\n");

+

+  /* The virt-v2v command. */

+  fprintf (fp, "(\n");

+  if (config->sudo)

+    fprintf (fp, "sudo -n ");

+  fprintf (fp, "virt-v2v");

+  if (config->verbose)

+    fprintf (fp, " -v -x");

+  if (feature_colours_option)

+    fprintf (fp, " --colours");

+  fprintf (fp, " -i libvirtxml");

+

+  if (config->output) {         /* -o */

+    fprintf (fp, " -o ");

+    print_quoted (fp, config->output);

+  }

+

+  switch (config->output_allocation) { /* -oa */

+  case OUTPUT_ALLOCATION_NONE:

+    /* nothing */

+    break;

+  case OUTPUT_ALLOCATION_SPARSE:

+    fprintf (fp, " -oa sparse");

+    break;

+  case OUTPUT_ALLOCATION_PREALLOCATED:

+    fprintf (fp, " -oa preallocated");

+    break;

+  default:

+    abort ();

+  }

+

+  if (config->output_format) {  /* -of */

+    fprintf (fp, " -of ");

+    print_quoted (fp, config->output_format);

+  }

+

+  if (config->output_storage) { /* -os */

+    fprintf (fp, " -os ");

+    print_quoted (fp, config->output_storage);

+  }

+

+  fprintf (fp, " --root first");

+  fprintf (fp, " %s/physical.xml", remote_dir);

+  /* no stdin, and send stdout and stderr to the same place */

+  fprintf (fp, " </dev/null 2>&1");

+  fprintf (fp, "\n");

+  fprintf (fp, "echo $? > %s/status", remote_dir);

+  fprintf (fp, "\n");

+  fprintf (fp, " ) | tee %s/virt-v2v-conversion-log.txt", remote_dir);

+  fprintf (fp, "\n");

+

+  fclose (fp);

+

+  return output;                /* caller frees */

+}

diff --git a/p2v/p2v.h b/p2v/p2v.h

index 12dd210..49c97b6 100644

--- a/p2v/p2v.h

+++ b/p2v/p2v.h

@@ -127,7 +127,7 @@ extern int conversion_is_running (void);

 /* ssh.c */

 extern int test_connection (struct config *);

 extern mexp_h *open_data_connection (struct config *, int *local_port, int *remote_port);

-extern mexp_h *start_remote_connection (struct config *, const char *remote_dir, const char *libvirt_xml, const char *dmesg);

+extern mexp_h *start_remote_connection (struct config *, const char *remote_dir, const char *libvirt_xml, const char *wrapper_script, const char *dmesg);

 extern const char *get_ssh_error (void);

 /* utils.c */

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

index 266c236..a8c762d 100644

--- a/p2v/ssh.c

+++ b/p2v/ssh.c

@@ -904,7 +904,7 @@ wait_for_prompt (mexp_h *h)

 mexp_h *

 start_remote_connection (struct config *config,

                          const char *remote_dir, const char *libvirt_xml,

-                         const char *dmesg)

+                         const char *wrapper_script, const char *dmesg)

 {

   mexp_h *h;

   char magic[9];

@@ -960,6 +960,29 @@ start_remote_connection (struct config *config,

   if (wait_for_prompt (h) == -1)

     goto error;

+  /* Upload the wrapper script to the remote directory. */

+  if (mexp_printf (h,

+                   "cat > '%s/virt-v2v-wrapper.sh' << '__%s__'\n"

+                   "%s"

+                   "__%s__\n",

+                   remote_dir, magic,

+                   wrapper_script,

+                   magic) == -1) {

+    set_ssh_error ("mexp_printf: %m");

+    goto error;

+  }

+

+  if (wait_for_prompt (h) == -1)

+    goto error;

+

+  if (mexp_printf (h, "chmod +x %s/virt-v2v-wrapper.sh\n", remote_dir) == -1) {

+    set_ssh_error ("mexp_printf: %m");

+    goto error;

+  }

+

+  if (wait_for_prompt (h) == -1)

+    goto error;

+

   if (dmesg != NULL) {

     /* Upload the physical host dmesg to the remote directory. */

     if (mexp_printf (h,

diff --git a/p2v/virt-p2v.pod b/p2v/virt-p2v.pod

index 5ceafa7..0c233c5 100644

--- a/p2v/virt-p2v.pod

+++ b/p2v/virt-p2v.pod

@@ -693,6 +693,13 @@ on the conversion server.  If conversion fails, you should examine

 this log file, and you may be asked to supply the B<complete>,

 B<unedited> log file in any bug reports or support tickets.

+=item F<virt-v2v-wrapper.sh>

+

+I<(during/after conversion)>

+

+This is the wrapper script which is used when running virt-v2v.  For

+interest only, do not attempt to run this script yourself.

+

 =back

 Before conversion actually begins, virt-p2v then makes one or more

@@ -729,10 +736,12 @@ used.  Secondly libguestfs creates an overlay on top of the NBD

 connection which stores writes in a temporary file on the conversion

 file.

-The final step is to send the S<C<virt-v2v -i libvirtxml physical.xml ...>>

-command to the conversion server over the control connection.  This

-references the F<physical.xml> file (see above), which in turn

-references the NBD listening port(s) of the data connection(s).

+The long S<C<virt-v2v -i libvirtxml physical.xml ...>> command is

+wrapped inside a wrapper script and uploaded to the conversion server.

+The final step is to run this wrapper script, in turn running the

+virt-v2v command.  The virt-v2v command references the F<physical.xml>

+file (see above), which in turn references the NBD listening port(s)

+of the data connection(s).

 Output from the virt-v2v command (messages, debugging etc) is saved

 both in the log file on the conversion server, and sent over the

-- 

2.7.4