New API: list-md-devices.

Return a list of Linux MD devices detected in the guest.

This API complements list_devices, list_partitions, list_lvs and
list_dm_devices.

appliance/init

@@ -70,6 +70,9 @@ ifconfig lo 127.0.0.1
 ifconfig eth0 169.254.2.10
 route add default gw 169.254.2.2
 
+# Scan for MDs.
+mdadm -As --auto=yes --run
+
 # Scan for LVM.
 modprobe dm_mod ||:
 

daemon/daemon.h

@@ -47,6 +47,7 @@ extern int xwrite (int sock, const void *buf, size_t len)
 extern int xread (int sock, void *buf, size_t len)
   __attribute__((__warn_unused_result__));
 
+extern int add_string_nodup (char ***argv, int *size, int *alloc, char *str);
 extern int add_string (char ***argv, int *size, int *alloc, const char *str);
 extern size_t count_strings (char *const *argv);
 extern void sort_strings (char **argv, int len);

daemon/guestfsd.c

@@ -415,10 +415,9 @@ xread (int sock, void *v_buf, size_t len)
 }
 
 int
-add_string (char ***argv, int *size, int *alloc, const char *str)
+add_string_nodup (char ***argv, int *size, int *alloc, char *str)
 {
   char **new_argv;
-  char *new_str;
 
   if (*size >= *alloc) {
     *alloc += 64;
@@ -426,25 +425,36 @@ add_string (char ***argv, int *size, int *alloc, const char *str)
     if (new_argv == NULL) {
       reply_with_perror ("realloc");
       free_strings (*argv);
+      *argv = NULL;
       return -1;
     }
     *argv = new_argv;
   }
 
+  (*argv)[*size] = str;
+
+  (*size)++;
+  return 0;
+}
+
+int
+add_string (char ***argv, int *size, int *alloc, const char *str)
+{
+  char *new_str;
+
   if (str) {
     new_str = strdup (str);
     if (new_str == NULL) {
       reply_with_perror ("strdup");
       free_strings (*argv);
+      *argv = NULL;
       return -1;
     }
-  } else
+  } else {
     new_str = NULL;
+  }
 
-  (*argv)[*size] = new_str;
-
-  (*size)++;
-  return 0;
+  return add_string_nodup (argv, size, alloc, new_str);
 }
 
 size_t

daemon/md.c

@@ -168,3 +168,65 @@ do_mdadm_create (const char *name, char *const *devices,
 
   return 0;
 }
+
+static int
+glob_errfunc (const char *epath, int eerrno)
+{
+  fprintf (stderr, "glob: failure reading %s: %s\n", epath, strerror (eerrno));
+  return 1;
+}
+
+char **
+do_list_md_devices (void)
+{
+  char **r = NULL;
+  int size = 0, alloc = 0;
+  glob_t mds;
+
+  memset(&mds, 0, sizeof(mds));
+
+#define PREFIX "/sys/block/md"
+#define SUFFIX "/md"
+
+  /* Look for directories under /sys/block matching md[0-9]*
+   * As an additional check, we also make sure they have a md subdirectory.
+   */
+  int err = glob (PREFIX "[0-9]*" SUFFIX, GLOB_ERR, glob_errfunc, &mds);
+  if (err == GLOB_NOSPACE) {
+    reply_with_error ("glob: returned GLOB_NOSPACE: "
+                      "rerun with LIBGUESTFS_DEBUG=1");
+    goto error;
+  } else if (err == GLOB_ABORTED) {
+    reply_with_error ("glob: returned GLOB_ABORTED: "
+                      "rerun with LIBGUESTFS_DEBUG=1");
+    goto error;
+  }
+
+  for (size_t i = 0; i < mds.gl_pathc; i++) {
+    size_t len = strlen (mds.gl_pathv[i]) - strlen (PREFIX) - strlen (SUFFIX);
+
+#define DEV "/dev/md"
+    char *dev = malloc (strlen(DEV) + len  + 1);
+    if (NULL == dev) {
+      reply_with_perror("malloc");
+      goto error;
+    }
+
+    char *n = dev;
+    n = mempcpy(n, DEV, strlen(DEV));
+    n = mempcpy(n, &mds.gl_pathv[i][strlen(PREFIX)], len);
+    *n = '\0';
+
+    if (add_string_nodup (&r, &size, &alloc, dev) == -1) goto error;
+  }
+
+  if (add_string_nodup (&r, &size, &alloc, NULL) == -1) goto error;
+  globfree (&mds);
+
+  return r;
+
+error:
+  globfree (&mds);
+  if (r != NULL) free_strings (r);
+  return NULL;
+}

generator/generator_actions.ml

@@ -6490,6 +6490,12 @@ If not set, this defaults to C<raid1>.
 
 =back");
 
+  ("list_md_devices", (RStringList "devices", [], []), 300, [],
+   [],
+   "list Linux md (RAID) devices",
+   "\
+List all Linux md devices.");
+
 ]
 
 let all_functions = non_daemon_functions @ daemon_functions

regressions/Makefile.am

@@ -45,6 +45,7 @@ TESTS = \
 	test-guestfish-tilde.sh \
 	test-inspect-fstab.sh \
 	test-launch-race.pl \
+	test-list-md-devices.sh \
 	test-luks.sh \
 	test-luks-list.sh \
 	test-lvm-filtering.sh \

regressions/test-list-md-devices.sh

@@ -0,0 +1,59 @@
+#!/bin/bash -
+# libguestfs
+# Copyright (C) 2011 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 guestfish list-md-devices command
+
+set -e
+
+output=$(
+../fish/guestfish <<EOF
+# Add 2 empty disks
+sparse md-test1.img 100M
+sparse md-test2.img 100M
+run
+
+# list-md-devices should return nothing
+list-md-devices
+
+# Create a raid1 based on the 2 disks
+mdadm-create test "/dev/sda /dev/sdb" level:raid1
+EOF
+)
+
+# Ensure list-md-devices above returned nothing
+if [ ! -z "$output" ]; then
+    echo "$0: error: output of list-md-devices with no MD devices did not match expected output"
+    echo $output
+    exit 1;
+fi
+
+# Ensure list-md-devices now returns the newly created md device
+output=$(
+../fish/guestfish -a md-test1.img -a md-test2.img <<EOF
+run
+list-md-devices
+EOF
+)
+
+if [ "$output" != "/dev/md127" ]; then
+    echo "$0: error: output of list-md-devices did not match expected output"
+    echo "$output"
+    exit 1
+fi
+
+rm -f md-test1.img md-test2.img

src/MAX_PROC_NR

@@ -1 +1 @@
-299
+300