tests: Add a protocol regression test for long error messages.

.gitignore

@@ -528,6 +528,7 @@ Makefile.in
 /tests/mount-local/test-parallel-mount-local
 /tests/mountable/test-internal-parse-mountable
 /tests/parallel/test-parallel
+/tests/protocol/test-error-messages
 /tests/regressions/rhbz501893
 /tests/regressions/rhbz790721
 /tests/regressions/rhbz914931

daemon/debug.c

@@ -65,6 +65,7 @@ static char *debug_help (const char *subcmd, size_t argc, char *const *const arg
 static char *debug_binaries (const char *subcmd, size_t argc, char *const *const argv);
 static char *debug_core_pattern (const char *subcmd, size_t argc, char *const *const argv);
 static char *debug_env (const char *subcmd, size_t argc, char *const *const argv);
+static char *debug_error (const char *subcmd, size_t argc, char *const *const argv);
 static char *debug_fds (const char *subcmd, size_t argc, char *const *const argv);
 static char *debug_ldd (const char *subcmd, size_t argc, char *const *const argv);
 static char *debug_ls (const char *subcmd, size_t argc, char *const *const argv);
@@ -83,6 +84,7 @@ static struct cmd cmds[] = {
   { "binaries", debug_binaries },
   { "core_pattern", debug_core_pattern },
   { "env", debug_env },
+  { "error", debug_error },
   { "fds", debug_fds },
   { "ldd", debug_ldd },
   { "ls", debug_ls },
@@ -318,6 +320,44 @@ debug_setenv (const char *subcmd, size_t argc, char *const *const argv)
   return ret;
 }
 
+/* Send back an error of different lengths. */
+static char *
+debug_error (const char *subcmd, size_t argc, char *const *const argv)
+{
+  unsigned len;
+  CLEANUP_FREE char *buf = NULL;
+
+  if (argc != 1) {
+  error:
+    reply_with_error ("debug error: expecting one arg: length of error message");
+    return NULL;
+  }
+
+  if (sscanf (argv[0], "%u", &len) != 1)
+    goto error;
+
+  if (len > 1000000) {
+    reply_with_error ("debug error: length argument too large");
+    return NULL;
+  }
+
+  buf = malloc (len + 1);
+  if (buf == NULL) {
+    reply_with_perror ("malloc");
+    return NULL;
+  }
+
+  memset (buf, 'a', len);
+  buf[len] = '\0';
+
+  /* So that the regression test can tell this is the true return path
+   * from the function and not an actual error, we set errno to some
+   * value that cannot be returned by any other error path.
+   */
+  reply_with_error_errno (EROFS, "%s", buf);
+  return NULL;
+}
+
 /* Return binaries in the appliance.
  * See tests/regressions/rhbz727178.sh
  */

tests/protocol/Makefile.am

@@ -17,7 +17,7 @@
 
 include $(top_srcdir)/subdir-rules.mk
 
-TESTS = \
+EXTRA_DIST = \
 	test-both-ends-cancel.sh \
 	test-cancellation-download-librarycancels.sh \
 	test-cancellation-upload-daemoncancels.sh \
@@ -28,5 +28,29 @@ TESTS = \
 
 TESTS_ENVIRONMENT = $(top_builddir)/run --test
 
-EXTRA_DIST = \
-	$(TESTS)
+TESTS = \
+	test-both-ends-cancel.sh \
+	test-cancellation-download-librarycancels.sh \
+	test-cancellation-upload-daemoncancels.sh \
+	test-error-messages \
+	test-launch-race.pl \
+	test-qemudie-killsub.sh \
+	test-qemudie-midcommand.sh \
+	test-qemudie-synch.sh
+
+check_PROGRAMS = test-error-messages
+
+test_error_messages_SOURCES = \
+	test-error-messages.c
+test_error_messages_CPPFLAGS = \
+	-DGUESTFS_PRIVATE=1 \
+	-I$(top_srcdir)/gnulib/lib -I$(top_builddir)/gnulib/lib \
+	-I$(top_srcdir)/src -I$(top_builddir)/src
+test_error_messages_CFLAGS = \
+	$(WARN_CFLAGS) $(WERROR_CFLAGS)
+test_error_messages_LDADD = \
+	$(top_builddir)/src/libutils.la \
+	$(top_builddir)/src/libguestfs.la \
+	$(LIBXML2_LIBS) \
+	$(LIBVIRT_LIBS) \
+	$(top_builddir)/gnulib/lib/libgnu.la

tests/protocol/test-error-messages.c

@@ -0,0 +1,83 @@
+/* libguestfs
+ * Copyright (C) 2014 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.
+ */
+
+/* Test error messages from the appliance.
+ *
+ * Note that we already test errno from the appliance (see
+ * tests/c-api/test-last-errno.c) so we don't need to test that here.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <errno.h>
+
+#include "guestfs.h"
+#include "guestfs_protocol.h" /* For GUESTFS_ERROR_LEN. */
+
+int
+main (int argc, char *argv[])
+{
+  guestfs_h *g;
+  size_t i;
+  int lengths[] = { 0, 1, 1024,
+                    GUESTFS_ERROR_LEN-2, GUESTFS_ERROR_LEN-1,
+                    GUESTFS_ERROR_LEN, GUESTFS_ERROR_LEN+1,
+                    GUESTFS_ERROR_LEN+2,
+                    GUESTFS_ERROR_LEN*2, -1 };
+  char len_s[64];
+  char *args[2];
+
+  g = guestfs_create ();
+  if (g == NULL) {
+    perror ("guestfs_create");
+    exit (EXIT_FAILURE);
+  }
+
+  if (guestfs_add_drive (g, "/dev/null") == -1)
+    exit (EXIT_FAILURE);
+
+  if (guestfs_launch (g) == -1)
+    exit (EXIT_FAILURE);
+
+  guestfs_push_error_handler (g, NULL, NULL);
+
+  for (i = 0; lengths[i] != -1; ++i) {
+    snprintf (len_s, sizeof len_s, "%d", lengths[i]);
+    args[0] = len_s;
+    args[1] = NULL;
+
+    if (guestfs_debug (g, "error", args) != NULL) {
+      fprintf (stderr, "%s: unexpected return value from 'debug error'\n",
+               argv[0]);
+      exit (EXIT_FAILURE);
+    }
+    /* EROFS is a magic value returned by debug_error in the daemon. */
+    if (guestfs_last_errno (g) != EROFS) {
+      fprintf (stderr, "%s: unexpected error from 'debug error': %s\n",
+               argv[0], guestfs_last_error (g));
+      exit (EXIT_FAILURE);
+    }
+    /* else OK */
+  }
+
+  guestfs_pop_error_handler (g);
+  guestfs_close (g);
+  exit (EXIT_SUCCESS);
+}