launch: Store drive information in guestfs_h

This is a NFC on its own, but provides a place-holder for drive metadata which
can be used after launch.

Fixes by RWMJ:

 - Fix the tests: this requires a new internal function 'debug-drives'
   that dumps out the g->drives information so it can be checked in
   two of the tests.  Previously these tests used 'debug-cmdline'.

 - Test file existence / use_cache_off in the add_drive_opts function,
   not when launching qemu in the child process.

 - Call free along error paths.

 - Add comments.

7 files changed, 137 insertions, 38 deletions

diff --git a/generator/generator_actions.ml b/generator/generator_actions.ml
index 86865b8c..4967ce20 100644
--- a/generator/generator_actions.ml
+++ b/generator/generator_actions.ml
@@ -1085,6 +1085,13 @@ Please read L<guestfs(3)/INSPECTION> for more details.");
 This returns the internal QEMU command line.  'debug' commands are
 not part of the formal API and can be removed or changed at any time.");
 
+  ("debug_drives", (RStringList "cmdline", [], []), -1, [NotInDocs],
+   [],
+   "debug the drives (internal use only)",
+   "\
+This returns the internal list of drives.  'debug' commands are
+not part of the formal API and can be removed or changed at any time.");
+
   ("add_domain", (RInt "nrdisks", [String "dom"], [String "libvirturi"; Bool "readonly"; String "iface"; Bool "live"; Bool "allowuuid"]), -1, [FishAlias "domain"],
    [],
    "add the disk(s) from a named libvirt domain",
diff --git a/regressions/test-add-domain.sh b/regressions/test-add-domain.sh
index d124b62d..ea6d3883 100755
--- a/regressions/test-add-domain.sh
+++ b/regressions/test-add-domain.sh
@@ -58,7 +58,7 @@ EOF
 
 ../fish/guestfish >test.out <<EOF
   domain guest libvirturi:test://$cwd/test.xml readonly:true
-  debug-cmdline
+  debug-drives
 EOF
 grep -sq "test1.img.*snapshot=on" test.out
 ! grep -sq "test1.img.*format" test.out
@@ -70,7 +70,7 @@ rm test3.img
 
 ../fish/guestfish >test.out <<EOF
   -domain guest libvirturi:test://$cwd/test.xml readonly:true
-  debug-cmdline
+  debug-drives
 EOF
 ! grep -sq "test1.img" test.out
 ! grep -sq "test2.img" test.out
diff --git a/regressions/test-guestfish-d.sh b/regressions/test-guestfish-d.sh
index 7fc52518..b95f62da 100755
--- a/regressions/test-guestfish-d.sh
+++ b/regressions/test-guestfish-d.sh
@@ -57,7 +57,7 @@ cat > test.xml <<EOF
 EOF
 
 ../fish/guestfish -c "test://$cwd/test.xml" --ro -d guest \
-  debug-cmdline </dev/null >test.out
+  debug-drives </dev/null >test.out
 grep -sq "test1.img.*snapshot=on" test.out
 ! grep -sq "test1.img.*format" test.out
 grep -sq "test2.img.*snapshot=on.*format=raw" test.out
diff --git a/src/guestfs-internal.h b/src/guestfs-internal.h
index cd732e16..7bdb4e44 100644
--- a/src/guestfs-internal.h
+++ b/src/guestfs-internal.h
@@ -149,6 +149,18 @@ struct event {
   void *opaque2;
 };
 
+/* Linked list of drives added to the handle. */
+struct drive {
+  struct drive *next;
+
+  char *path;
+
+  int readonly;
+  char *format;
+  char *iface;
+  int use_cache_off;
+};
+
 struct guestfs_h
 {
   struct guestfs_h *next;	/* Linked list of open handles. */
@@ -156,6 +168,8 @@ struct guestfs_h
   /* State: see the state machine diagram in the man page guestfs(3). */
   enum state state;
 
+  struct drive *drives;         /* Drives added by add-drive* APIs. */
+
   int fd[2];			/* Stdin/stdout of qemu. */
   int sock;			/* Daemon communications socket. */
   pid_t pid;			/* Qemu PID. */
@@ -359,6 +373,7 @@ extern void guestfs___trace (guestfs_h *g, const char *fs, ...)
 extern const char *guestfs___persistent_tmpdir (void);
 extern void guestfs___print_timestamped_message (guestfs_h *g, const char *fs, ...);
 extern void guestfs___free_inspect_info (guestfs_h *g);
+extern void guestfs___free_drives (struct drive **drives);
 extern int guestfs___set_busy (guestfs_h *g);
 extern int guestfs___end_busy (guestfs_h *g);
 extern int guestfs___send (guestfs_h *g, int proc_nr, uint64_t progress_hint, uint64_t optargs_bitmask, xdrproc_t xdrp, char *args);
@@ -380,8 +395,8 @@ extern int guestfs___match2 (guestfs_h *g, const char *str, const pcre *re, char
 extern int guestfs___match3 (guestfs_h *g, const char *str, const pcre *re, char **ret1, char **ret2, char **ret3);
 extern int guestfs___feature_available (guestfs_h *g, const char *feature);
 extern void guestfs___free_string_list (char **);
-extern size_t guestfs___checkpoint_cmdline (guestfs_h *g);
-extern void guestfs___rollback_cmdline (guestfs_h *g, size_t pos);
+extern struct drive ** guestfs___checkpoint_drives (guestfs_h *g);
+extern void guestfs___rollback_drives (guestfs_h *g, struct drive **i);
 extern void guestfs___call_callbacks_void (guestfs_h *g, uint64_t event);
 extern void guestfs___call_callbacks_message (guestfs_h *g, uint64_t event, const char *buf, size_t buf_len);
 extern void guestfs___call_callbacks_array (guestfs_h *g, uint64_t event, const uint64_t *array, size_t array_len);
diff --git a/src/guestfs.c b/src/guestfs.c
index f7ad9674..170d0d32 100644
--- a/src/guestfs.c
+++ b/src/guestfs.c
@@ -206,6 +206,7 @@ guestfs_close (guestfs_h *g)
   g->events = NULL;
 
   guestfs___free_inspect_info (g);
+  guestfs___free_drives (&g->drives);
 
   /* Close sockets. */
   if (g->fd[0] >= 0)
@@ -994,3 +995,21 @@ guestfs___free_string_list (char **argv)
     free (argv[i]);
   free (argv);
 }
+
+void
+guestfs___free_drives (struct drive **drives)
+{
+  struct drive *i = *drives;
+  *drives = NULL;
+
+  while (i != NULL) {
+    struct drive *next = i->next;
+
+    free (i->path);
+    free (i->format);
+    free (i->iface);
+    free (i);
+
+    i = next;
+  }
+}
diff --git a/src/launch.c b/src/launch.c
index dbf8ba67..d6e99f72 100644
--- a/src/launch.c
+++ b/src/launch.c
@@ -139,23 +139,18 @@ add_cmdline (guestfs_h *g, const char *str)
   return 0;
 }
 
-size_t
-guestfs___checkpoint_cmdline (guestfs_h *g)
+struct drive **
+guestfs___checkpoint_drives (guestfs_h *g)
 {
-  return g->cmdline_size;
+  struct drive **i = &g->drives;
+  while (*i != NULL) i = &((*i)->next);
+  return i;
 }
 
 void
-guestfs___rollback_cmdline (guestfs_h *g, size_t pos)
+guestfs___rollback_drives (guestfs_h *g, struct drive **i)
 {
-  size_t i;
-
-  assert (g->cmdline_size >= pos);
-
-  for (i = pos; i < g->cmdline_size; ++i)
-    free (g->cmdline[i]);
-
-  g->cmdline_size = pos;
+  guestfs___free_drives(i);
 }
 
 /* Internal command to return the command line. */
@@ -178,6 +173,39 @@ guestfs__debug_cmdline (guestfs_h *g)
   return r;                     /* caller frees */
 }
 
+/* Internal command to return the list of drives. */
+char **
+guestfs__debug_drives (guestfs_h *g)
+{
+  size_t i, count;
+  char **ret;
+  struct drive *drv;
+
+  for (count = 0, drv = g->drives; drv; count++, drv = drv->next)
+    ;
+
+  ret = safe_malloc (g, sizeof (char *) * (count + 1));
+
+  for (i = 0, drv = g->drives; drv; i++, drv = drv->next) {
+    size_t len = 64 + strlen (drv->path) + strlen (drv->iface);
+    if (drv->format) len += strlen (drv->format);
+
+    ret[i] = safe_malloc (g, len);
+
+    snprintf (ret[i], len, "file=%s%s%s%s%s,if=%s",
+              drv->path,
+              drv->readonly ? ",snapshot=on" : "",
+              drv->use_cache_off ? ",cache=off" : "",
+              drv->format ? ",format=" : "",
+              drv->format ? drv->format : "",
+              drv->iface);
+  }
+
+  ret[count] = NULL;
+
+  return ret;                   /* caller frees */
+}
+
 int
 guestfs__config (guestfs_h *g,
                  const char *qemu_param, const char *qemu_value)
@@ -259,8 +287,9 @@ guestfs__add_drive_opts (guestfs_h *g, const char *filename,
                          const struct guestfs_add_drive_opts_argv *optargs)
 {
   int readonly;
-  const char *format;
-  const char *iface;
+  char *format;
+  char *iface;
+  int use_cache_off;
 
   if (strchr (filename, ',') != NULL) {
     error (g, _("filename cannot contain ',' (comma) character"));
@@ -270,18 +299,22 @@ guestfs__add_drive_opts (guestfs_h *g, const char *filename,
   readonly = optargs->bitmask & GUESTFS_ADD_DRIVE_OPTS_READONLY_BITMASK
              ? optargs->readonly : 0;
   format = optargs->bitmask & GUESTFS_ADD_DRIVE_OPTS_FORMAT_BITMASK
-           ? optargs->format : NULL;
+           ? safe_strdup (g, optargs->format) : NULL;
   iface = optargs->bitmask & GUESTFS_ADD_DRIVE_OPTS_IFACE_BITMASK
-          ? optargs->iface : DRIVE_IF;
+          ? safe_strdup (g, optargs->iface) : safe_strdup (g, DRIVE_IF);
 
   if (format && !valid_format_iface (format)) {
     error (g, _("%s parameter is empty or contains disallowed characters"),
            "format");
+    free (format);
+    free (iface);
     return -1;
   }
   if (!valid_format_iface (iface)) {
     error (g, _("%s parameter is empty or contains disallowed characters"),
            "iface");
+    free (format);
+    free (iface);
     return -1;
   }
 
@@ -289,31 +322,34 @@ guestfs__add_drive_opts (guestfs_h *g, const char *filename,
    * checks for the existence of the file.  For readonly we have
    * to do the check explicitly.
    */
-  int use_cache_off = readonly ? 0 : test_cache_off (g, filename);
-  if (use_cache_off == -1)
+  use_cache_off = readonly ? 0 : test_cache_off (g, filename);
+  if (use_cache_off == -1) {
+    free (format);
+    free (iface);
     return -1;
+  }
 
   if (readonly) {
     if (access (filename, F_OK) == -1) {
       perrorf (g, "%s", filename);
+      free (format);
+      free (iface);
       return -1;
     }
   }
 
-  /* Construct the final -drive parameter. */
-  size_t len = 64 + strlen (filename) + strlen (iface);
-  if (format) len += strlen (format);
-  char buf[len];
+  struct drive **i = &(g->drives);
+  while (*i != NULL) i = &((*i)->next);
 
-  snprintf (buf, len, "file=%s%s%s%s%s,if=%s",
-            filename,
-            readonly ? ",snapshot=on" : "",
-            use_cache_off ? ",cache=off" : "",
-            format ? ",format=" : "",
-            format ? format : "",
-            iface);
+  *i = safe_malloc (g, sizeof (struct drive));
+  (*i)->next = NULL;
+  (*i)->path = safe_strdup (g, filename);
+  (*i)->readonly = readonly;
+  (*i)->format = format;
+  (*i)->iface = iface;
+  (*i)->use_cache_off = use_cache_off;
 
-  return guestfs__config (g, "-drive", buf);
+  return 0;
 }
 
 int
@@ -433,7 +469,7 @@ launch_appliance (guestfs_h *g)
   /* At present you must add drives before starting the appliance.  In
    * future when we enable hotplugging you won't need to do this.
    */
-  if (!g->cmdline) {
+  if (!g->drives) {
     error (g, _("you must call guestfs_add_drive before guestfs_launch"));
     return -1;
   }
@@ -527,6 +563,28 @@ launch_appliance (guestfs_h *g)
     alloc_cmdline (g);
     g->cmdline[0] = g->qemu;
 
+    /* Add drives */
+    struct drive *i = g->drives;
+    while (i != NULL) {
+      /* Construct the final -drive parameter. */
+      size_t len = 64 + strlen (i->path) + strlen (i->iface);
+      if (i->format) len += strlen (i->format);
+      char buf[len];
+
+      snprintf (buf, len, "file=%s%s%s%s%s,if=%s",
+                i->path,
+                i->readonly ? ",snapshot=on" : "",
+                i->use_cache_off ? ",cache=off" : "",
+                i->format ? ",format=" : "",
+                i->format ? i->format : "",
+                i->iface);
+
+      add_cmdline (g, "-drive");
+      add_cmdline (g, buf);
+
+      i = i->next;
+    }
+
     if (qemu_supports (g, "-nodefconfig"))
       add_cmdline (g, "-nodefconfig");
 
diff --git a/src/virt.c b/src/virt.c
index 58cb999d..cc11c68a 100644
--- a/src/virt.c
+++ b/src/virt.c
@@ -392,10 +392,10 @@ guestfs___add_libvirt_dom (guestfs_h *g, virDomainPtr dom,
   /* Checkpoint the command line around the operation so that either
    * all disks are added or none are added.
    */
-  cmdline_pos = guestfs___checkpoint_cmdline (g);
+  struct drive **cp = guestfs___checkpoint_drives (g);
   r = guestfs___for_each_disk (g, dom, add_disk, &optargs2);
   if (r == -1)
-    guestfs___rollback_cmdline (g, cmdline_pos);
+    guestfs___rollback_drives (g, cp);
 
   return r;
 }