tests: Add a regression test for RHBZ#914931.

This involves adding a new test API which crashes the appliance in the
middle of a simulated upload, then a test which uses that API to test
for the libguestfs (library-side) crash.

.gitignore

@@ -444,6 +444,7 @@ Makefile.in
 /tests/parallel/test-parallel
 /tests/regressions/rhbz501893
 /tests/regressions/rhbz790721
+/tests/regressions/rhbz914931
 /tests/rsync/rsyncd.pid
 /test-tool/libguestfs-test-tool
 /test-tool/libguestfs-test-tool.1

daemon/debug.c

@@ -73,6 +73,7 @@ static char *debug_qtrace (const char *subcmd, size_t argc, char *const *const a
 static char *debug_segv (const char *subcmd, size_t argc, char *const *const argv);
 static char *debug_setenv (const char *subcmd, size_t argc, char *const *const argv);
 static char *debug_sh (const char *subcmd, size_t argc, char *const *const argv);
+static void deliberately_cause_a_segfault (void);
 
 static struct cmd cmds[] = {
   { "help", debug_help },
@@ -210,14 +211,7 @@ debug_fds (const char *subcmd, size_t argc, char *const *const argv)
 static char *
 debug_segv (const char *subcmd, size_t argc, char *const *const argv)
 {
-  /* http://blog.llvm.org/2011/05/what-every-c-programmer-should-know.html
-   * "Dereferencing a NULL Pointer: contrary to popular belief,
-   * dereferencing a null pointer in C is undefined. It is not defined
-   * to trap [...]"
-   */
-  volatile int *ptr = NULL;
-  /* coverity[var_deref_op] */
-  *ptr = 1;
+  deliberately_cause_a_segfault ();
   return NULL;
 }
 
@@ -689,3 +683,64 @@ do_debug_upload (const char *filename, int mode)
 
   return 0;
 }
+
+/* Internal function used only when testing
+ * https://bugzilla.redhat.com/show_bug.cgi?id=914931
+ */
+
+static int
+crash_cb (void *countv, const void *buf, size_t len)
+{
+  int *countp = countv;
+
+  (*countp)--;
+  sleep (1);
+
+  if (*countp == 0)
+    deliberately_cause_a_segfault ();
+
+  return 0;
+}
+
+/* Has one FileIn parameter. */
+int
+do_internal_rhbz914931 (int count)
+{
+  int r;
+
+  if (count <= 0 || count > 1000) {
+    reply_with_error ("count out of range");
+    return -1;
+  }
+
+  r = receive_file (crash_cb, &count);
+  if (r == -1) {		/* write error */
+    int err = errno;
+    cancel_receive ();
+    errno = err;
+    reply_with_error ("write error");
+    return -1;
+  }
+  if (r == -2) {		/* cancellation from library */
+    /* This error is ignored by the library since it initiated the
+     * cancel.  Nevertheless we must send an error reply here.
+     */
+    reply_with_error ("file upload cancelled");
+    return -1;
+  }
+
+  return 0;
+}
+
+static void
+deliberately_cause_a_segfault (void)
+{
+  /* http://blog.llvm.org/2011/05/what-every-c-programmer-should-know.html
+   * "Dereferencing a NULL Pointer: contrary to popular belief,
+   * dereferencing a null pointer in C is undefined. It is not defined
+   * to trap [...]"
+   */
+  volatile int *ptr = NULL;
+  /* coverity[var_deref_op] */
+  *ptr = 1;
+}

generator/actions.ml

@@ -10735,6 +10735,17 @@ device. That is, not a partition or a logical device." };
     longdesc = "\
 Parse a mountable string." };
 
+  { defaults with
+    name = "internal_rhbz914931";
+    style = RErr, [FileIn "filename"; Int "count"], [];
+    proc_nr = Some 397;
+    visibility = VInternal;
+    cancellable = true;
+    shortdesc = "used only to test rhbz914931 (internal use only)";
+    longdesc = "\
+This is only used to debug RHBZ#914931.  Note that this
+deliberately crashes guestfsd." };
+
 ]
 
 (* Non-API meta-commands available only in guestfish.

src/MAX_PROC_NR

@@ -1 +1 @@
-396
+397

tests/regressions/Makefile.am

@@ -30,6 +30,7 @@ TESTS = \
 	rhbz790721 \
 	rhbz811649.sh \
 	rhbz895904.sh \
+	rhbz914931 \
 	test-noexec-stack.pl
 
 tests_not_run = \
@@ -42,7 +43,8 @@ TESTS_ENVIRONMENT = \
 
 check_PROGRAMS = \
 	rhbz501893 \
-	rhbz790721
+	rhbz790721 \
+	rhbz914931
 
 rhbz501893_SOURCES = rhbz501893.c
 rhbz501893_CPPFLAGS = \
@@ -63,6 +65,17 @@ rhbz790721_CFLAGS = \
 rhbz790721_LDADD = \
 	$(top_builddir)/src/libguestfs.la
 
+rhbz914931_SOURCES = rhbz914931.c
+rhbz914931_CPPFLAGS = \
+	-I$(top_srcdir)/src -I$(top_builddir)/src \
+	-DGUESTFS_PRIVATE=1
+rhbz914931_CFLAGS = \
+	-pthread \
+	$(WARN_CFLAGS) $(WERROR_CFLAGS) \
+	$(GPROF_CFLAGS) $(GCOV_CFLAGS)
+rhbz914931_LDADD = \
+	$(top_builddir)/src/libguestfs.la
+
 EXTRA_DIST = \
 	$(TESTS) \
 	$(tests_not_run) \

tests/regressions/rhbz914931.c

@@ -0,0 +1,70 @@
+/* libguestfs
+ * Copyright (C) 2013 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.
+ */
+
+/* Regression test for RHBZ#914931.  Simulate an appliance crash
+ * during a FileIn operation.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <assert.h>
+#include <errno.h>
+
+#include "guestfs.h"
+#include "guestfs-internal-frontend.h"
+
+int
+main (int argc, char *argv[])
+{
+  guestfs_h *g;
+  int r;
+
+  g = guestfs_create ();
+  if (!g) {
+    perror ("guestfs_create");
+    exit (EXIT_FAILURE);
+  }
+
+  if (guestfs_add_drive_opts (g, "/dev/null",
+                              GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw",
+                              GUESTFS_ADD_DRIVE_OPTS_READONLY, 1,
+                              -1) == -1)
+    exit (EXIT_FAILURE);
+
+  if (guestfs_launch (g) == -1)
+    exit (EXIT_FAILURE);
+
+  /* Perform the upload-with-crash.  Prior to RHBZ#914931 being fixed,
+   * this would also cause libguestfs (ie. us) to segfault.
+   */
+  r = guestfs_internal_rhbz914931 (g, "/dev/zero",
+                                   5 /* seconds before appliance crash */);
+
+  /* We expect that call to fail, not segfault. */
+  assert (r == -1);
+
+  /* Close the handle. */
+  guestfs_close (g);
+
+  /* It's success if we get this far without the program segfaulting. */
+  exit (EXIT_SUCCESS);
+}