[Libguestfs] [PATCH 2/3] inspection: Handle MD devices in fstab

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 | 330 +++++++++++++++++++++++++++++++++++++++++++++++- 1 files changed, 323 insertions(+), 7 deletions(-) diff --git a/src/inspect_fs_unix.c b/src/inspect_fs_unix.c index b68dde1..63317b3 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; @@ -109,6 +112,7 @@ compile_regexps (void) COMPILE (re_major_minor, "(\\d+)\\.(\\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); } @@ -129,6 +133,7 @@ free_regexps (void) pcre_free (re_major_minor); pcre_free (re_xdev); pcre_free (re_cciss); + pcre_free (re_mdN); pcre_free (re_freebsd); pcre_free (re_netbsd); } @@ -139,10 +144,37 @@ 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 int 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 int map_app_md_devices (guestfs_h *g, Hash_table **map); +static int 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, @@ -444,7 +476,7 @@ 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; @@ -727,6 +759,11 @@ check_fstab (guestfs_h *g, struct inspect_fs *fs) char *spec, *mp; int r; + /* 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) == -1) return -1; + entries = guestfs_aug_match (g, "/files/etc/fstab/*[label() != '#comment']"); if (entries == NULL) goto error; @@ -747,17 +784,19 @@ check_fstab (guestfs_h *g, struct inspect_fs *fs) goto error; } - r = add_fstab_entry (g, fs, spec, mp); + r = add_fstab_entry (g, fs, spec, mp, md_map); free (spec); free (mp); if (r == -1) goto error; } + if (md_map) hash_free (md_map); guestfs___free_string_list (entries); return 0; error: + if (md_map) hash_free (md_map); if (entries) guestfs___free_string_list (entries); return -1; } @@ -772,7 +811,7 @@ 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/") || @@ -804,7 +843,7 @@ 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. @@ -841,6 +880,274 @@ 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 int +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 0; + + return -1; +} + +/* Create a mapping of uuids to appliance md device names */ +static int +map_app_md_devices (guestfs_h *g, Hash_table **map) +{ + char **mds = NULL; + int n = 0; + + /* 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_md_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) == -1) { + /* Invalid UUID is weird, but not fatal. */ + debug(g, "inspect-os: guestfs_md_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); + break; + + default: + n++; + } + } + + guestfs___free_string_list(detail); + } + + guestfs___free_string_list(mds); + + return n; + +error: + hash_free(*map); *map = NULL; + guestfs___free_string_list(mds); + + return -1; +} + +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 int +map_md_devices(guestfs_h *g, Hash_table **map) +{ + Hash_table *app_map = NULL; + char **matches = NULL; + *map = NULL; + + /* Get a map of md device uuids to their device names in the appliance */ + int n_app_md_devices = map_app_md_devices(g, &app_map); + if (n_app_md_devices == -1) goto error; + + /* Nothing to do if there are no md devices */ + if (n_app_md_devices == 0) { + hash_free(app_map); + return 0; + } + + /* Get all arrays listed in mdadm.conf */ + matches = guestfs_aug_match(g, "/files/etc/mdadm.conf/array"); + if (!matches) goto error; + + /* Log a debug message if we've got md devices, but nothing in mdadm.conf */ + if (matches[0] == NULL) { + debug(g, "Appliance has MD devices, but augeas returned no array matches " + "in mdadm.conf"); + guestfs___free_string_list(matches); + hash_free(app_map); + return 0; + } + + *map = hash_initialize(16, NULL, mdadm_app_hash, mdadm_app_cmp, + mdadm_app_free); + if (!*map) g->abort_cb(); + + for (char **match = matches; *match != NULL; match++) { + /* Get device name and uuid for each array */ + char *dev_path = safe_asprintf(g, "%s/devicename", *match); + char *dev = guestfs_aug_get(g, dev_path); + free(dev_path); + if (!dev) goto error; + + char *uuid_path = safe_asprintf(g, "%s/uuid", *match); + char *uuid = guestfs_aug_get(g, uuid_path); + free(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) == -1) { + /* 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); + + return 0; + +error: + if (app_map) hash_free(app_map); + if (matches) guestfs___free_string_list(matches); + if (*map) hash_free(*map); + + return -1; +} + /* 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 @@ -848,7 +1155,7 @@ 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; @@ -943,6 +1250,15 @@ resolve_fstab_device (guestfs_h *g, const char *spec) free (part); guestfs___free_string_list (devices); } + else if (md_map && (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); + + free(disk); + } 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 -- 1.7.7.3