[Libguestfs] [PATCH] osinfo: revamp db reading (RHBZ#1359652)
Pino Toscano
ptoscano at redhat.com
Mon Jul 25 15:47:05 UTC 2016
More recent versions of libosinfo switched the internal directory with
the XML files of OSes to a different layout (still with the same XML
format), causing libguestfs to not read them anymore. Furthermore, the
internal directory is going to disappear soon, replaced by a public
osinfo database [1].
Revamp the way libguestfs reads the data: first try the upcoming osinfo
layout, falling back to the current libosinfo layout (which is the same
as osinfo), and then to the old flat layout.
[1] https://gitlab.com/libosinfo/libosinfo/blob/master/docs/database-layout.txt
---
src/osinfo.c | 168 +++++++++++++++++++++++++++++++++++++++++++++++++----------
1 file changed, 140 insertions(+), 28 deletions(-)
diff --git a/src/osinfo.c b/src/osinfo.c
index f4e2c71..0caacfa 100644
--- a/src/osinfo.c
+++ b/src/osinfo.c
@@ -55,6 +55,7 @@
#include <assert.h>
#include <sys/types.h>
#include <libintl.h>
+#include <sys/stat.h>
#include <libxml/parser.h>
#include <libxml/xpath.h>
@@ -148,36 +149,109 @@ guestfs_int_osinfo_map (guestfs_h *g, const struct guestfs_isoinfo *isoinfo,
* Note that failure to find or parse the XML files is *not* a fatal
* error, since we should fall back silently if these are not
* available. Although we'll emit some debug if this happens.
+ *
+ * Try to use the shared osinfo database layout (and location) first:
+ * https://gitlab.com/libosinfo/libosinfo/blob/master/docs/database-layout.txt
*/
-#define LIBOSINFO_DB_OS_PATH LIBOSINFO_DB_PATH "/oses"
-
static int read_osinfo_db_xml (guestfs_h *g, const char *filename);
+static int read_osinfo_db_flat (guestfs_h *g, const char *directory);
+static int read_osinfo_db_three_levels (guestfs_h *g, const char *directory);
+static int read_osinfo_db_directory (guestfs_h *g, const char *directory);
+
static int
read_osinfo_db (guestfs_h *g)
{
- DIR *dir = NULL;
- struct dirent *d;
int r;
size_t i;
+ const char *path;
assert (osinfo_db_size == 0);
- dir = opendir (LIBOSINFO_DB_OS_PATH);
+ /* (1) Try the shared osinfo directory, using either the
+ * $OSINFO_SYSTEM_DIR envvar or its default value.
+ */
+ path = getenv ("OSINFO_SYSTEM_DIR");
+ if (path == NULL)
+ path = "/usr/share/osinfo";
+ r = read_osinfo_db_three_levels (g, path);
+ if (r == -1)
+ goto error;
+ else if (r == 1)
+ return 0;
+
+ /* (2) Try the libosinfo directory, using the newer three-directory
+ * layout ($LIBOSINFO_DB_PATH / "os" / $group-ID / [file.xml]).
+ */
+ r = read_osinfo_db_three_levels (g, LIBOSINFO_DB_PATH "/os");
+ if (r == -1)
+ goto error;
+ else if (r == 1)
+ return 0;
+
+ /* (3) Try the libosinfo directory, using the old flat directory
+ * layout ($LIBOSINFO_DB_PATH / "oses" / [file.xml]).
+ */
+ r = read_osinfo_db_flat (g, LIBOSINFO_DB_PATH "/oses");
+ if (r == -1)
+ goto error;
+ else if (r == 1)
+ return 0;
+
+ /* Nothing found. */
+ return 0;
+
+ error:
+ /* Fatal error: free any database entries which have been read, and
+ * mark the database as having a permanent error.
+ */
+ if (osinfo_db_size > 0) {
+ for (i = 0; i < (size_t) osinfo_db_size; ++i)
+ free_osinfo_db_entry (&osinfo_db[i]);
+ }
+ free (osinfo_db);
+ osinfo_db = NULL;
+ osinfo_db_size = -1;
+
+ return -1;
+}
+
+static int
+read_osinfo_db_flat (guestfs_h *g, const char *directory)
+{
+ debug (g, "osinfo: loading flat database from %s", directory);
+
+ return read_osinfo_db_directory (g, directory);
+}
+
+static int
+read_osinfo_db_three_levels (guestfs_h *g, const char *directory)
+{
+ DIR *dir;
+ int r;
+
+ dir = opendir (directory);
if (!dir) {
- debug (g, "osinfo: %s: %s", LIBOSINFO_DB_OS_PATH, strerror (errno));
+ debug (g, "osinfo: %s: %s", directory, strerror (errno));
return 0; /* This is not an error: RHBZ#948324. */
}
- debug (g, "osinfo: loading database from %s", LIBOSINFO_DB_OS_PATH);
+ debug (g, "osinfo: loading 3-level-directories database from %s", directory);
for (;;) {
+ struct dirent *d;
+ CLEANUP_FREE char *pathname = NULL;
+ struct stat sb;
+
errno = 0;
d = readdir (dir);
if (!d) break;
- if (STRSUFFIX (d->d_name, ".xml")) {
- r = read_osinfo_db_xml (g, d->d_name);
+ pathname = safe_asprintf (g, "%s/%s", directory, d->d_name);
+
+ /* Iterate only on directories. */
+ if (stat (pathname, &sb) == 0 && S_ISDIR (sb.st_mode)) {
+ r = read_osinfo_db_directory (g, pathname);
if (r == -1)
goto error;
}
@@ -185,7 +259,7 @@ read_osinfo_db (guestfs_h *g)
/* Check for failure in readdir. */
if (errno != 0) {
- perrorf (g, "readdir: %s", LIBOSINFO_DB_OS_PATH);
+ perrorf (g, "readdir: %s", directory);
goto error;
}
@@ -193,26 +267,67 @@ read_osinfo_db (guestfs_h *g)
r = closedir (dir);
dir = NULL;
if (r == -1) {
- perrorf (g, "closedir: %s", LIBOSINFO_DB_OS_PATH);
+ perrorf (g, "closedir: %s", directory);
goto error;
}
- return 0;
+ return 1;
error:
if (dir)
closedir (dir);
- /* Fatal error: free any database entries which have been read, and
- * mark the database as having a permanent error.
- */
- if (osinfo_db_size > 0) {
- for (i = 0; i < (size_t) osinfo_db_size; ++i)
- free_osinfo_db_entry (&osinfo_db[i]);
+ return -1;
+}
+
+static int
+read_osinfo_db_directory (guestfs_h *g, const char *directory)
+{
+ DIR *dir;
+ int r;
+
+ dir = opendir (directory);
+ if (!dir) {
+ debug (g, "osinfo: %s: %s", directory, strerror (errno));
+ return 0; /* This is not an error: RHBZ#948324. */
}
- free (osinfo_db);
- osinfo_db = NULL;
- osinfo_db_size = -1;
+
+ for (;;) {
+ struct dirent *d;
+
+ errno = 0;
+ d = readdir (dir);
+ if (!d) break;
+
+ if (STRSUFFIX (d->d_name, ".xml")) {
+ CLEANUP_FREE char *pathname = NULL;
+
+ pathname = safe_asprintf (g, "%s/%s", directory, d->d_name);
+ r = read_osinfo_db_xml (g, pathname);
+ if (r == -1)
+ goto error;
+ }
+ }
+
+ /* Check for failure in readdir. */
+ if (errno != 0) {
+ perrorf (g, "readdir: %s", directory);
+ goto error;
+ }
+
+ /* Close the directory handle. */
+ r = closedir (dir);
+ dir = NULL;
+ if (r == -1) {
+ perrorf (g, "closedir: %s", directory);
+ goto error;
+ }
+
+ return 1;
+
+ error:
+ if (dir)
+ closedir (dir);
return -1;
}
@@ -221,13 +336,12 @@ static int read_iso_node (guestfs_h *g, xmlNodePtr iso_node, struct osinfo *osin
static int read_media_node (guestfs_h *g, xmlXPathContextPtr xpathCtx, xmlNodePtr media_node, struct osinfo *osinfo);
static int read_os_node (guestfs_h *g, xmlXPathContextPtr xpathCtx, xmlNodePtr os_node, struct osinfo *osinfo);
-/* Read a single XML file from LIBOSINFO_DB_OS_PATH/filename. Only
- * memory allocation failures are fatal errors here.
+/* Read a single XML file from pathname (which is a full path).
+ * Only memory allocation failures are fatal errors here.
*/
static int
-read_osinfo_db_xml (guestfs_h *g, const char *filename)
+read_osinfo_db_xml (guestfs_h *g, const char *pathname)
{
- CLEANUP_FREE char *pathname = NULL;
CLEANUP_XMLFREEDOC xmlDocPtr doc = NULL;
CLEANUP_XMLXPATHFREECONTEXT xmlXPathContextPtr xpathCtx = NULL;
CLEANUP_XMLXPATHFREEOBJECT xmlXPathObjectPtr xpathObj = NULL;
@@ -236,8 +350,6 @@ read_osinfo_db_xml (guestfs_h *g, const char *filename)
struct osinfo *osinfo;
size_t i;
- pathname = safe_asprintf (g, "%s/%s", LIBOSINFO_DB_OS_PATH, filename);
-
doc = xmlReadFile (pathname, NULL, XML_PARSE_NONET);
if (doc == NULL) {
debug (g, "osinfo: unable to parse XML file %s", pathname);
@@ -298,7 +410,7 @@ read_osinfo_db_xml (guestfs_h *g, const char *filename)
#if 0
debug (g, "osinfo: %s: %s%s%s%s=> arch %s live %s product %s type %d distro %d version %d.%d",
- filename,
+ pathname,
osinfo->re_system_id ? "<system-id/> " : "",
osinfo->re_volume_id ? "<volume-id/> " : "",
osinfo->re_publisher_id ? "<publisher-id/> " : "",
--
2.7.4
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