[Libguestfs] [PATCH 7/8] inspection: Handle MD devices in fstab
Matthew Booth
mbooth at redhat.com
Wed Nov 23 14:00:56 UTC 2011
This patch fixes inspection when fstab contains devices md devices
specified as /dev/mdN. The appliance creates these devices without reference to
the guest's mdadm.conf so, for e.g. /dev/md0 in the guest will often be created
as /dev/md127 in the appliance. With this patch, we match the uuids of detected
md devices against uuids specified in mdadm.conf, and map them appropriately
when we encounter them in fstab.
---
src/inspect_fs_unix.c | 317 +++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 310 insertions(+), 7 deletions(-)
diff --git a/src/inspect_fs_unix.c b/src/inspect_fs_unix.c
index 3046e02..3be49d5 100644
--- a/src/inspect_fs_unix.c
+++ b/src/inspect_fs_unix.c
@@ -38,6 +38,8 @@
#include "c-ctype.h"
#include "ignore-value.h"
#include "xstrtol.h"
+#include "hash.h"
+#include "hash-pjw.h"
#include "guestfs.h"
#include "guestfs-internal.h"
@@ -65,6 +67,7 @@ static pcre *re_major_minor;
static pcre *re_aug_seq;
static pcre *re_xdev;
static pcre *re_cciss;
+static pcre *re_mdN;
static pcre *re_first_partition;
static pcre *re_freebsd;
static pcre *re_netbsd;
@@ -110,6 +113,7 @@ compile_regexps (void)
COMPILE (re_aug_seq, "/\\d+$", 0);
COMPILE (re_xdev, "^/dev/(h|s|v|xv)d([a-z]+)(\\d*)$", 0);
COMPILE (re_cciss, "^/dev/(cciss/c\\d+d\\d+)(?:p(\\d+))?$", 0);
+ COMPILE (re_mdN, "^(/dev/md\\d+)$", 0);
COMPILE (re_freebsd, "^/dev/ad(\\d+)s(\\d+)([a-z])$", 0);
COMPILE (re_netbsd, "^NetBSD (\\d+)\\.(\\d+)", 0);
}
@@ -131,6 +135,7 @@ free_regexps (void)
pcre_free (re_aug_seq);
pcre_free (re_xdev);
pcre_free (re_cciss);
+ pcre_free (re_mdN);
pcre_free (re_freebsd);
pcre_free (re_netbsd);
}
@@ -141,10 +146,37 @@ static int check_hostname_redhat (guestfs_h *g, struct inspect_fs *fs);
static int check_hostname_freebsd (guestfs_h *g, struct inspect_fs *fs);
static int check_fstab (guestfs_h *g, struct inspect_fs *fs);
static int add_fstab_entry (guestfs_h *g, struct inspect_fs *fs,
- const char *spec, const char *mp);
-static char *resolve_fstab_device (guestfs_h *g, const char *spec);
+ const char *spec, const char *mp,
+ Hash_table *md_map);
+static char *resolve_fstab_device (guestfs_h *g, const char *spec,
+ Hash_table *md_map);
static int inspect_with_augeas (guestfs_h *g, struct inspect_fs *fs, const char **configfiles, int (*f) (guestfs_h *, struct inspect_fs *));
+/* Hash structure for uuid->path lookups */
+typedef struct md_uuid {
+ uint32_t uuid[4];
+ char *path;
+} md_uuid;
+
+static size_t uuid_hash(const void *x, size_t table_size);
+static bool uuid_cmp(const void *x, const void *y);
+static void md_uuid_free(void *x);
+
+static bool parse_uuid(const char *str, uint32_t *uuid);
+
+/* Hash structure for path(mdadm)->path(appliance) lookup */
+typedef struct {
+ char *mdadm;
+ char *app;
+} mdadm_app;
+
+static size_t mdadm_app_hash(const void *x, size_t table_size);
+static bool mdadm_app_cmp(const void *x, const void *y);
+static void mdadm_app_free(void *x);
+
+static bool map_app_md_devices (guestfs_h *g, Hash_table **map);
+static bool map_md_devices(guestfs_h *g, Hash_table **map);
+
/* Set fs->product_name to the first line of the release file. */
static int
parse_release_file (guestfs_h *g, struct inspect_fs *fs,
@@ -446,7 +478,7 @@ guestfs___check_linux_root (guestfs_h *g, struct inspect_fs *fs)
* which filesystems are used by the operating system and how they
* are mounted.
*/
- const char *configfiles[] = { "/etc/fstab", NULL };
+ const char *configfiles[] = { "/etc/fstab", "/etc/mdadm.conf", NULL };
if (inspect_with_augeas (g, fs, configfiles, check_fstab) == -1)
return -1;
@@ -688,6 +720,11 @@ check_hostname_freebsd (guestfs_h *g, struct inspect_fs *fs)
static int
check_fstab (guestfs_h *g, struct inspect_fs *fs)
{
+ /* Generate a map of MD device paths listed in /etc/mdadm.conf to MD device
+ * paths in the guestfs appliance */
+ Hash_table *md_map;
+ if (!map_md_devices (g, &md_map)) return -1;
+
char **lines = guestfs_aug_ls (g, "/files/etc/fstab");
if (lines == NULL) goto error;
@@ -714,7 +751,7 @@ check_fstab (guestfs_h *g, struct inspect_fs *fs)
goto error;
}
- int r = add_fstab_entry (g, fs, spec, mp);
+ int r = add_fstab_entry (g, fs, spec, mp, md_map);
free (spec);
free (mp);
@@ -722,10 +759,12 @@ check_fstab (guestfs_h *g, struct inspect_fs *fs)
}
}
+ hash_free (md_map);
guestfs___free_string_list (lines);
return 0;
error:
+ hash_free (md_map);
if (lines) guestfs___free_string_list (lines);
return -1;
}
@@ -740,7 +779,7 @@ error:
*/
static int
add_fstab_entry (guestfs_h *g, struct inspect_fs *fs,
- const char *spec, const char *mp)
+ const char *spec, const char *mp, Hash_table *md_map)
{
/* Ignore certain mountpoints. */
if (STRPREFIX (mp, "/dev/") ||
@@ -772,7 +811,7 @@ add_fstab_entry (guestfs_h *g, struct inspect_fs *fs,
device = safe_strdup (g, fs->device);
else if (STRPREFIX (spec, "/dev/"))
/* Resolve guest block device names. */
- device = resolve_fstab_device (g, spec);
+ device = resolve_fstab_device (g, spec, md_map);
/* If we haven't resolved the device successfully by this point,
* we don't care, just ignore it.
@@ -809,6 +848,263 @@ add_fstab_entry (guestfs_h *g, struct inspect_fs *fs,
return 0;
}
+/* Compute a uuid hash as a simple xor of of its 4 32bit components */
+static size_t
+uuid_hash(const void *x, size_t table_size)
+{
+ const md_uuid *a = x;
+
+ size_t h = a->uuid[0];
+ for (size_t i = 1; i < 4; i++) {
+ h ^= a->uuid[i];
+ }
+
+ return h % table_size;
+}
+
+static bool
+uuid_cmp(const void *x, const void *y)
+{
+ const md_uuid *a = x;
+ const md_uuid *b = y;
+
+ for (size_t i = 0; i < 1; i++) {
+ if (a->uuid[i] != b->uuid[i]) return false;
+ }
+
+ return true;
+}
+
+static void
+md_uuid_free(void *x)
+{
+ md_uuid *a = x;
+ free(a->path);
+ free(a);
+}
+
+/* Taken from parse_uuid in mdadm */
+static bool
+parse_uuid(const char *str, uint32_t *uuid)
+{
+ for (size_t i = 0; i < 4; i++) uuid[i] = 0;
+
+ int hit = 0; /* number of Hex digIT */
+ char c;
+ while ((c = *str++)) {
+ int n;
+ if (c >= '0' && c <= '9')
+ n = c - '0';
+ else if (c >= 'a' && c <= 'f')
+ n = 10 + c - 'a';
+ else if (c >= 'A' && c <= 'F')
+ n = 10 + c - 'A';
+ else if (strchr(":. -", c))
+ continue;
+ else return false;
+
+ if (hit < 32) {
+ uuid[hit / 8] <<= 4;
+ uuid[hit / 8] += n;
+ }
+ hit++;
+ }
+ if (hit == 32) return true;
+
+ return false;
+}
+
+/* Create a mapping of uuids to appliance md device names */
+static bool
+map_app_md_devices (guestfs_h *g, Hash_table **map)
+{
+ int ret = false;
+
+ char **mds = NULL;
+
+ /* A hash mapping uuids to md device names */
+ *map = hash_initialize(16, NULL, uuid_hash, uuid_cmp, md_uuid_free);
+ if (*map == NULL) g->abort_cb();
+
+ mds = guestfs_list_md_devices(g);
+ if (mds == NULL) goto error;
+
+ for (char **md = mds; *md != NULL; md++) {
+ char **detail = guestfs_mdadm_detail(g, *md);
+ if (detail == NULL) goto error;
+
+ /* Iterate over keys until we find uuid */
+ char **i;
+ for (i = detail; *i != NULL; i += 2) {
+ if (STREQ(*i, "uuid")) break;
+ }
+
+ /* We found it */
+ if (*i) {
+ /* Next item is the uuid value */
+ i++;
+
+ md_uuid *entry = safe_malloc(g, sizeof(md_uuid));
+ entry->path = safe_strdup(g, *md);
+
+ if (!parse_uuid(*i, entry->uuid)) {
+ /* Invalid UUID is weird, but not fatal. */
+ debug(g, "inspect-os: guestfs_mdadm_detail returned invalid "
+ "uuid for %s: %s", *md, *i);
+ guestfs___free_string_list(detail);
+ md_uuid_free(entry);
+ continue;
+ }
+
+ const void *matched = NULL;
+ switch (hash_insert_if_absent(*map, entry, &matched)) {
+ case -1:
+ g->abort_cb();
+
+ case 0:
+ /* Duplicate uuid in for md device is weird, but not fatal. */
+ debug(g, "inspect-os: md devices %s and %s have the same uuid",
+ ((md_uuid *)matched)->path, entry->path);
+ md_uuid_free(entry);
+
+ default:
+ ;;
+ }
+ }
+
+ guestfs___free_string_list(detail);
+ }
+
+ guestfs___free_string_list(mds);
+
+ return true;
+
+error:
+ hash_free(*map); *map = NULL;
+ guestfs___free_string_list(mds);
+
+ return false;
+}
+
+static size_t
+mdadm_app_hash(const void *x, size_t table_size)
+{
+ const mdadm_app *a = x;
+ return hash_pjw(a->mdadm, table_size);
+}
+
+static bool
+mdadm_app_cmp(const void *x, const void *y)
+{
+ const mdadm_app *a = x;
+ const mdadm_app *b = y;
+
+ return strcmp(a->mdadm, b->mdadm) == 0;
+}
+
+static void
+mdadm_app_free(void *x)
+{
+ mdadm_app *a = x;
+ free(a->mdadm);
+ free(a->app);
+ free(a);
+}
+
+/* Get a map of md device names in mdadm.conf to their device names in the
+ * appliance */
+static bool
+map_md_devices(guestfs_h *g, Hash_table **map)
+{
+ Hash_table *app_map = NULL;
+ char **matches = NULL;
+ char *dev_path = NULL;
+ char *uuid_path = NULL;
+ *map = NULL;
+
+ /* Get a map of md device uuids to their device names in the appliance */
+ if (!map_app_md_devices(g, &app_map)) goto error;
+
+ *map = hash_initialize(16, NULL, mdadm_app_hash, mdadm_app_cmp,
+ mdadm_app_free);
+ if (!*map) g->abort_cb();
+
+ /* Get all arrays listed in mdadm.conf */
+ matches = guestfs_aug_match(g, "/files/etc/mdadm.conf/array");
+ if (!matches) goto error;
+
+ for (char **match = matches; *match != NULL; match++) {
+ /* Get device name and uuid for each array */
+ dev_path = safe_asprintf(g, "%s/devicename", *match);
+ uuid_path = safe_asprintf(g, "%s/uuid", *match);
+
+ char *dev = guestfs_aug_get(g, dev_path);
+ if (!dev) goto error;
+
+ char *uuid = guestfs_aug_get(g, uuid_path);
+ if (!uuid) {
+ free(dev);
+ goto error;
+ }
+
+ /* Parse the uuid into an md_uuid structure so we can look it up in the
+ * uuid->appliance device map */
+ md_uuid mdadm;
+ mdadm.path = dev;
+ if (!parse_uuid(uuid, mdadm.uuid)) {
+ /* Invalid uuid. Weird, but not fatal. */
+ debug(g, "inspect-os: mdadm.conf contains invalid uuid for %s: %s",
+ dev, uuid);
+ free(dev);
+ free(uuid);
+ continue;
+ }
+ free(uuid);
+
+ /* If there's a corresponding uuid in the appliance, create a new
+ * entry in the transitive map */
+ md_uuid *app = hash_lookup(app_map, &mdadm);
+ if (app) {
+ mdadm_app *entry = safe_malloc(g, sizeof(mdadm_app));
+ entry->mdadm = dev;
+ entry->app = safe_strdup(g, app->path);
+
+ switch (hash_insert_if_absent(*map, entry, NULL)) {
+ case -1:
+ g->abort_cb();
+
+ case 0:
+ /* Duplicate uuid in for md device is weird, but not fatal. */
+ debug(g, "inspect-os: mdadm.conf contains multiple entries for %s",
+ app->path);
+ mdadm_app_free(entry);
+ continue;
+
+ default:
+ ;;
+ }
+ } else {
+ free(dev);
+ }
+ }
+
+ hash_free(app_map);
+ guestfs___free_string_list(matches);
+ free(dev_path);
+ free(uuid_path);
+
+ return true;
+
+error:
+ if (app_map) hash_free(app_map);
+ if (matches) guestfs___free_string_list(matches);
+ free(dev_path);
+ free(uuid_path);
+ if (*map) hash_free(*map);
+
+ return false;
+}
+
/* Resolve block device name to the libguestfs device name, eg.
* /dev/xvdb1 => /dev/vdb1; and /dev/mapper/VG-LV => /dev/VG/LV. This
* assumes that disks were added in the same order as they appear to
@@ -816,7 +1112,7 @@ add_fstab_entry (guestfs_h *g, struct inspect_fs *fs,
* anything we don't recognize unchanged.
*/
static char *
-resolve_fstab_device (guestfs_h *g, const char *spec)
+resolve_fstab_device (guestfs_h *g, const char *spec, Hash_table *md_map)
{
char *device = NULL;
char *type, *slice, *disk, *part;
@@ -911,6 +1207,13 @@ resolve_fstab_device (guestfs_h *g, const char *spec)
free (part);
guestfs___free_string_list (devices);
}
+ else if ((disk = match1 (g, spec, re_mdN)) != NULL) {
+ mdadm_app entry;
+ entry.mdadm = disk;
+
+ mdadm_app *app = hash_lookup (md_map, &entry);
+ if (app) device = safe_strdup (g, app->app);
+ }
else if (match3 (g, spec, re_freebsd, &disk, &slice, &part)) {
/* FreeBSD disks are organized quite differently. See:
* http://www.freebsd.org/doc/handbook/disk-organization.html
--
1.7.6.4
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