tests: Rewrite parallel mount-local test in C.

tests/mount-local/Makefile.am

@@ -0,0 +1,40 @@
+# libguestfs
+# Copyright (C) 2009-2012 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.
+
+include $(top_srcdir)/subdir-rules.mk
+
+if HAVE_FUSE
+
+TESTS = test-parallel-mount-local
+
+TESTS_ENVIRONMENT = $(top_builddir)/run --test $(VG)
+
+check_PROGRAMS = $(TESTS)
+
+test_parallel_mount_local_SOURCES = test-parallel-mount-local.c
+test_parallel_mount_local_CFLAGS = \
+	-DGUESTFS_WARN_DEPRECATED=1 \
+	-pthread \
+	-I$(top_srcdir)/gnulib/lib -I$(top_builddir)/gnulib/lib \
+	-I$(top_srcdir)/src -I$(top_builddir)/src \
+	$(FUSE_CFLAGS) \
+	$(WARN_CFLAGS) $(WERROR_CFLAGS)
+test_parallel_mount_local_LDADD = \
+	$(FUSE_LIBS) -lulockmgr \
+	$(top_builddir)/src/libguestfs.la
+
+endif

tests/mount-local/test-parallel-mount-local.c

@@ -0,0 +1,486 @@
+/* libguestfs
+ * Copyright (C) 2012 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 mount-local APIs in parallel. */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <inttypes.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <time.h>
+#include <signal.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <errno.h>
+#include <error.h>
+
+#include <pthread.h>
+
+#include "guestfs.h"
+
+#include "ignore-value.h"
+
+#define TOTAL_TIME 60           /* Seconds, excluding launch. */
+#define DEBUG 1                 /* Print overview debugging messages. */
+#define MIN_THREADS 2
+#define MAX_THREADS 12
+#define MBYTES_PER_THREAD 900
+
+#define STREQ(a,b) (strcmp((a),(b)) == 0)
+
+struct thread_state {
+  pthread_t thread;             /* Thread handle. */
+  char *filename;               /* Disk image. */
+  char *mp;                     /* Mount point. */
+  int exit_status;              /* Thread exit status. */
+};
+static struct thread_state threads[MAX_THREADS];
+static size_t nr_threads;
+
+static void *start_thread (void *) __attribute__((noreturn));
+static void test_mountpoint (const char *mp);
+static void cleanup_thread_state (void);
+static char *read_line_from (const char *cmd);
+static int unmount (const char *mp, unsigned flags);
+#define UNMOUNT_SILENT 1
+#define UNMOUNT_RMDIR  2
+
+static volatile sig_atomic_t quit = 0;
+
+static void
+catch_sigint (int signal)
+{
+  static char cleaning_up[] = "\ngot signal, cleaning up ...\n";
+
+  if (quit == 0) {
+    quit = 1;
+    ignore_value (write (2, cleaning_up, sizeof cleaning_up));
+  }
+}
+
+int
+main (int argc, char *argv[])
+{
+  size_t i, mbytes;
+  char *skip, *mbytes_s;
+  struct sigaction sa;
+  int fd, r, errors = 0;
+  void *status;
+
+  srandom (time (NULL));
+
+  /* If the --test flag is given, then this is the test subprocess. */
+  if (argc == 3 && STREQ (argv[1], "--test")) {
+    test_mountpoint (argv[2]);
+    exit (EXIT_SUCCESS);
+  }
+
+  /* Allow the test to be skipped by setting an environment variable. */
+  skip = getenv ("SKIP_TEST_PARALLEL_MOUNT_LOCAL");
+  if (skip && STREQ (skip, "1")) {
+    fprintf (stderr, "%s: test skipped because environment variable set.\n",
+             argv[0]);
+    exit (EXIT_SUCCESS);
+  }
+
+  if (access ("/dev/fuse", W_OK) == -1) {
+    fprintf (stderr, "%s: test skipped because /dev/fuse is not writable.\n",
+             argv[0]);
+    exit (EXIT_SUCCESS);
+  }
+
+  /* Choose the number of threads based on the amount of free memory. */
+  mbytes_s = read_line_from ("LANG=C free -m | "
+                             "grep 'buffers/cache' | awk '{print $NF}'");
+  if (!mbytes_s)
+    nr_threads = MIN_THREADS; /* default */
+  else {
+    if (sscanf (mbytes_s, "%zu", &mbytes) != 1)
+      error (EXIT_FAILURE, 0, "expecting integer but got \"%s\"", mbytes_s);
+    free (mbytes_s);
+    nr_threads = mbytes / MBYTES_PER_THREAD;
+    if (nr_threads < MIN_THREADS)
+      nr_threads = MIN_THREADS;
+    else if (nr_threads > MAX_THREADS)
+      nr_threads = MAX_THREADS;
+  }
+
+  memset (&sa, 0, sizeof sa);
+  sa.sa_handler = catch_sigint;
+  sa.sa_flags = SA_RESTART;
+  sigaction (SIGINT, &sa, NULL);
+  sigaction (SIGQUIT, &sa, NULL);
+
+  if (DEBUG)
+    printf ("starting test with %zu threads\n", nr_threads);
+
+  for (i = 0; i < nr_threads; ++i) {
+    /* Create an image file and a mount point for this thread to use. */
+    if (asprintf (&threads[i].filename, "test%zu.img", i) == -1)
+      error (EXIT_FAILURE, errno, "asprintf");
+    if (asprintf (&threads[i].mp, "mp%zu", i) == -1)
+      error (EXIT_FAILURE, errno, "asprintf");
+
+    fd = open (threads[i].filename, O_WRONLY|O_CREAT|O_NOCTTY|O_CLOEXEC, 0600);
+    if (fd == -1) {
+      cleanup_thread_state ();
+      error (EXIT_FAILURE, errno, "open: %s", threads[i].filename);
+    }
+
+    if (ftruncate (fd, 512*1024*1024) == -1) {
+      cleanup_thread_state ();
+      error (EXIT_FAILURE, errno, "truncate: %s", threads[i].filename);
+    }
+
+    if (close (fd) == -1) {
+      cleanup_thread_state ();
+      error (EXIT_FAILURE, errno, "close: %s", threads[i].filename);
+    }
+
+    rmdir (threads[i].mp);
+    if (mkdir (threads[i].mp, 0700) == -1) {
+      cleanup_thread_state ();
+      error (EXIT_FAILURE, errno, "mkdir: %s", threads[i].mp);
+    }
+
+    /* Start the thread. */
+    if (DEBUG) {
+      printf ("%-8s : starting thread\n", threads[i].mp);
+      fflush (stdout);
+    }
+    r = pthread_create (&threads[i].thread, NULL, start_thread,
+                        &threads[i]);
+    if (r != 0) {
+      cleanup_thread_state ();
+      error (EXIT_FAILURE, r, "pthread_create");
+    }
+  }
+
+  /* Wait for the threads to exit. */
+  for (i = 0; i < nr_threads; ++i) {
+    r = pthread_join (threads[i].thread, &status);
+    if (r != 0) {
+      cleanup_thread_state ();
+      error (EXIT_FAILURE, r, "pthread_join");
+    }
+    if (*(int *)status != 0) {
+      fprintf (stderr, "%s: thread returned an error\n", threads[i].mp);
+      errors++;
+    }
+  }
+
+  cleanup_thread_state ();
+
+  exit (errors == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
+}
+
+/* Run the test in a single thread. */
+static void *
+start_thread (void *statevp)
+{
+  struct thread_state *state = statevp;
+  guestfs_h *g;
+  time_t start_t, t;
+  pid_t pid;
+  int status, r;
+  guestfs_error_handler_cb old_error_cb;
+  void *old_error_cb_data;
+
+  g = guestfs_create ();
+  if (g == NULL) {
+    perror ("guestfs_create");
+    state->exit_status = 1;
+    pthread_exit (&state->exit_status);
+  }
+
+  if (guestfs_add_drive_opts (g, state->filename,
+                              GUESTFS_ADD_DRIVE_OPTS_FORMAT, "raw", -1) == -1)
+    goto error;
+  if (guestfs_launch (g) == -1)
+    goto error;
+
+  if (guestfs_part_disk (g, "/dev/sda", "mbr") == -1)
+    goto error;
+  if (guestfs_mkfs (g, "ext2", "/dev/sda1") == -1)
+    goto error;
+  if (guestfs_mount (g, "/dev/sda1", "/") == -1)
+    goto error;
+
+  time (&start_t);
+
+  for (;;) {
+    /* Keep testing until we run out of time. */
+    time (&t);
+    if (quit || t - start_t >= TOTAL_TIME)
+      break;
+
+    if (DEBUG) {
+      printf ("%-8s < mounting filesystem\n", state->mp);
+      fflush (stdout);
+    }
+
+    if (guestfs_mount_local (g, state->mp, -1) == -1)
+      goto error;
+
+    /* Run the test in an exec'd subprocess.  This minimizes the
+     * chance of shared file descriptors or other resources [ie.
+     * across clone] causing deadlocks in FUSE.
+     */
+    pid = fork ();
+    if (pid == -1) {
+      perror ("fork");
+      goto error;
+    }
+
+    if (pid == 0) { /* child */
+      setpgid (0, 0);           /* so we don't get ^C from parent */
+      execlp ("./test-parallel-mount-local",
+              "test-parallel-mount-local", "--test", state->mp, NULL);
+      perror ("execlp");
+      goto error;
+    }
+
+    /* Run the FUSE main loop.  We don't really want to see libguestfs
+     * errors here since these are harmless.
+     */
+    old_error_cb = guestfs_get_error_handler (g, &old_error_cb_data);
+    guestfs_set_error_handler (g, NULL, NULL);
+    r = guestfs_mount_local_run (g);
+    guestfs_set_error_handler (g, old_error_cb, old_error_cb_data);
+
+    /* Wait for child process to exit and catch any errors from it. */
+  again:
+    if (waitpid (pid, &status, 0) == -1) {
+      if (errno == EINTR)
+        goto again;
+      perror ("waitpid");
+      goto error;
+    }
+    if (WIFEXITED (status)) {
+      if (WEXITSTATUS (status) != 0) {
+        fprintf (stderr, "%s: test exited with non-zero status %d\n",
+                 state->mp, WEXITSTATUS (status));
+        goto error;
+      }
+    } else if (WIFSIGNALED (status)) {
+      fprintf (stderr, "%s: subprocess killed by signal %d\n",
+               state->mp, WTERMSIG (status));
+      goto error;
+    } else if (WIFSTOPPED (status)) {
+      fprintf (stderr, "%s: subprocess stopped by signal %d\n",
+               state->mp, WSTOPSIG (status));
+      goto error;
+    }
+
+    if (r == -1) /* guestfs_mount_local_run above failed */
+      goto error;
+  }
+
+  if (DEBUG) {
+    printf ("%-8s : shutting down handle and thread\n", state->mp);
+    fflush (stdout);
+  }
+
+  if (guestfs_shutdown (g) == -1)
+    pthread_exit (&state->exit_status);
+  guestfs_close (g);
+
+  /* Test finished successfully. */
+  state->exit_status = 0;
+  pthread_exit (&state->exit_status);
+
+ error:
+  guestfs_close (g);
+  state->exit_status = 1;
+  pthread_exit (&state->exit_status);
+}
+
+/* This runs as a subprocess and must test the mountpoint at 'mp'. */
+static void
+test_mountpoint (const char *mp)
+{
+  int nr_passes = 5 + (random () & 31);
+  int pass;
+  int ret = EXIT_FAILURE;
+  FILE *fp;
+
+  if (!mp || STREQ (mp, ""))
+    error (EXIT_FAILURE, 0, "%s: invalid or empty mountpoint path", __func__);
+
+  if (DEBUG) {
+    printf ("%-8s | testing filesystem\n", mp);
+    fflush (stdout);
+  }
+
+  if (chdir (mp) == -1) {
+    perror (mp);
+    goto error;
+  }
+
+  /* Run through the same set of tests repeatedly a number of times.
+   * The aim of this stress test is repeated mount/unmount, not
+   * testing the FUSE data path, so we don't do much here.
+   */
+  for (pass = 0; pass < nr_passes; ++pass) {
+    if (mkdir ("tmp.d", 0700) == -1) {
+      perror ("mkdir: tmp.d");
+      goto error;
+    }
+    fp = fopen ("file", "w");
+    if (fp == NULL) {
+      perror ("create: file");
+      goto error;
+    }
+    fprintf (fp, "hello world\n");
+    fclose (fp);
+    if (rename ("tmp.d", "newdir") == -1) {
+      perror ("rename tmp.d newdir");
+      goto error;
+    }
+    if (link ("file", "newfile") == -1) {
+      perror ("link: file newfile");
+      goto error;
+    }
+    if (rmdir ("newdir") == -1) {
+      perror ("rmdir: newdir");
+      goto error;
+    }
+    if (unlink ("file") == -1) {
+      perror ("unlink: file");
+      goto error;
+    }
+    if (unlink ("newfile") == -1) {
+      perror ("unlink: newfile");
+      goto error;
+    }
+  }
+
+  if (DEBUG) {
+    printf ("%-8s | test finished\n", mp);
+    fflush (stdout);
+  }
+
+  ret = EXIT_SUCCESS;
+ error:
+  ignore_value (chdir (".."));
+  if (unmount (mp, 0) == -1)
+    error (EXIT_FAILURE, 0, "fusermount -u %s: failed, see earlier errors", mp);
+
+  if (DEBUG) {
+    printf ("%-8s > unmounted filesystem\n", mp);
+    fflush (stdout);
+  }
+
+  exit (ret);
+}
+
+/* We may need to retry this a few times because of processes which
+ * run in the background jumping into mountpoints.  Only display
+ * errors if it still fails after many retries.
+ */
+static int
+unmount (const char *mp, unsigned flags)
+{
+  char logfile[256];
+  char cmd[256];
+  int tries = 5, status, r;
+
+  if (flags & UNMOUNT_RMDIR) {
+    r = rmdir (mp);
+    if (r == 0 || (r == -1 && errno != EBUSY && errno != ENOTCONN))
+      return 0;
+  }
+
+  snprintf (logfile, sizeof logfile, "%s.fusermount.tmp", mp);
+  unlink (logfile);
+
+  snprintf (cmd, sizeof cmd, "fusermount -u %s >> %s 2>&1", mp, logfile);
+
+  while (tries > 0) {
+    status = system (cmd);
+    if (WIFEXITED (status) && WEXITSTATUS (status) == 0)
+      break;
+    sleep (1);
+    tries--;
+  }
+
+  if (tries == 0) {             /* Failed. */
+    if (!(flags & UNMOUNT_SILENT)) {
+      fprintf (stderr, "fusermount -u %s: command failed:\n", mp);
+      snprintf (cmd, sizeof cmd, "cat %s", logfile);
+      ignore_value (system (cmd));
+    }
+    unlink (logfile);
+    return -1;
+  }
+
+  unlink (logfile);
+
+  if (flags & UNMOUNT_RMDIR) {
+    if (rmdir (mp) == -1)
+      return -1;
+  }
+
+  return 0;
+}
+
+/* Cleanup thread state. */
+static void
+cleanup_thread_state (void)
+{
+  size_t i;
+
+  for (i = 0; i < nr_threads; ++i) {
+    if (threads[i].filename) {
+      unlink (threads[i].filename);
+      free (threads[i].filename);
+    }
+
+    if (threads[i].mp) {
+      unmount (threads[i].mp, UNMOUNT_SILENT|UNMOUNT_RMDIR);
+      free (threads[i].mp);
+    }
+  }
+}
+
+/* Run external command and read the first line of output. */
+static char *
+read_line_from (const char *cmd)
+{
+  FILE *pp;
+  char *ret = NULL;
+  size_t n;
+
+  pp = popen (cmd, "r");
+  if (pp == NULL)
+    error (EXIT_FAILURE, errno, "%s: external command failed", cmd);
+
+  if (getline (&ret, &n, pp) == -1)
+    error (EXIT_FAILURE, errno, "could not read line from external command");
+
+  if (pclose (pp) == -1)
+    error (EXIT_FAILURE, errno, "pclose");
+
+  return ret;
+}