blkid: split the RHEL5 which can't support some options

[libguestfs.git] / daemon / blkid.c

diff --git a/daemon/blkid.c b/daemon/blkid.c
index a619730..f23eac6 100644 (file)
--- a/daemon/blkid.c
+++ b/daemon/blkid.c
@@ -13,7 +13,7 @@
  *
  * 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  */
 
 #include <config.h>
@@ -33,17 +33,16 @@ get_blkid_tag (const char *device, const char *tag)
   char *out, *err;
   int r;
 
-  /* Kill the cache file, forcing blkid to reread values from the
-   * original filesystems.  In blkid there is a '-p' option which is
-   * supposed to do this, but (a) it doesn't work and (b) that option
-   * is not supported in RHEL 5.
-   */
-  unlink ("/etc/blkid/blkid.tab");
-
-  r = command (&out, &err,
-               "blkid", "-o", "value", "-s", tag, device, NULL);
-  if (r == -1) {
-    reply_with_error ("%s: %s", device, err);
+  r = commandr (&out, &err,
+                "blkid",
+                /* Adding -c option kills all caching, even on RHEL 5. */
+                "-c", "/dev/null",
+                "-o", "value", "-s", tag, device, NULL);
+  if (r != 0 && r != 2) {
+    if (r >= 0)
+      reply_with_error ("%s: %s (blkid returned %d)", device, err, r);
+    else
+      reply_with_error ("%s: %s", device, err);
     free (out);
     free (err);
     return NULL;
@@ -51,6 +50,14 @@ get_blkid_tag (const char *device, const char *tag)
 
   free (err);
 
+  if (r == 2) {                 /* means UUID etc not found */
+    free (out);
+    out = strdup ("");
+    if (out == NULL)
+      reply_with_perror ("strdup");
+    return out;
+  }
+
   /* Trim trailing \n if present. */
   size_t len = strlen (out);
   if (len > 0 && out[len-1] == '\n')
@@ -64,3 +71,156 @@ do_vfs_type (const char *device)
 {
   return get_blkid_tag (device, "TYPE");
 }
+
+char *
+do_vfs_label (const char *device)
+{
+  return get_blkid_tag (device, "LABEL");
+}
+
+char *
+do_vfs_uuid (const char *device)
+{
+  return get_blkid_tag (device, "UUID");
+}
+
+/* RHEL5 blkid doesn't have the -p(partition info) option and the
+ * -i(I/O limits) option so we must test for these options the first
+ * time the function is called.
+ */
+static int
+test_blkid_p_opt(void)
+{
+  static int result;
+  char *err = NULL;
+
+  int r = commandr(NULL, &err, "blkid", "-p", "/dev/null", NULL);
+  if (r == -1) {
+    reply_with_error("could not run 'blkid' command: %s", err);
+    free(err);
+    return -1;
+  }
+
+  if (strstr(err, "invalid option --"))
+    result = 0;
+  else
+    result = 1;
+  free(err);
+  return result;
+}
+
+static char **
+blkid_with_p_opt(const char *device)
+{
+  int r;
+  char *out = NULL, *err = NULL;
+  char **lines = NULL;
+  char **ret = NULL;
+  int size = 0, alloc = 0;
+
+  r = command(&out, &err, "blkid", "-c", "/dev/null",
+               "-p", "-i", "-o", "export", device, NULL);
+  if (r == -1) {
+    reply_with_error("%s", err);
+    goto error;
+  }
+
+  /* Split the command output into lines */
+  lines = split_lines(out);
+  if (lines == NULL) {
+    reply_with_perror("malloc");
+    goto error;
+  }
+
+  /* Parse the output of blkid -p -i -o export:
+   * UUID=b6d83437-c6b4-4bf0-8381-ef3fc3578590
+   * VERSION=1.0
+   * TYPE=ext2
+   * USAGE=filesystem
+   * MINIMUM_IO_SIZE=512
+   * PHYSICAL_SECTOR_SIZE=512
+   * LOGICAL_SECTOR_SIZE=512
+   * PART_ENTRY_SCHEME=dos
+   * PART_ENTRY_TYPE=0x83
+   * PART_ENTRY_NUMBER=6
+   * PART_ENTRY_OFFSET=642875153
+   * PART_ENTRY_SIZE=104857600
+   * PART_ENTRY_DISK=8:0
+   */
+  for (char **i = lines; *i != NULL; i++) {
+    char *line = *i;
+
+    /* Skip blank lines (shouldn't happen) */
+    if (line[0] == '\0') continue;
+
+    /* Split the line in 2 at the equals sign */
+    char *eq = strchr(line, '=');
+    if (eq) {
+      *eq = '\0'; eq++;
+
+      /* Add the key/value pair to the output */
+      if (add_string(&ret, &size, &alloc, line) == -1 ||
+          add_string(&ret, &size, &alloc, eq) == -1) goto error;
+    } else {
+      fprintf(stderr, "blkid: unexpected blkid output ignored: %s", line);
+    }
+  }
+
+  if (add_string(&ret, &size, &alloc, NULL) == -1) goto error;
+
+  free(out);
+  free(err);
+  free(lines);
+
+  return ret;
+
+error:
+  free(out);
+  free(err);
+  if (lines) free(lines);
+  if (ret) free_strings(ret);
+
+  return NULL;
+}
+
+static char **
+blkid_without_p_opt(const char *device)
+{
+  char **ret = NULL;
+  int size = 0, alloc = 0;
+
+  if (add_string(&ret, &size, &alloc, "TYPE") == -1) goto error;
+  if (add_string(&ret, &size, &alloc, get_blkid_tag(device, "TYPE")) == -1)
+    goto error;
+  if (add_string(&ret, &size, &alloc, "LABEL") == -1) goto error;
+  if (add_string(&ret, &size, &alloc, get_blkid_tag(device, "LABEL")) == -1)
+    goto error;
+  if (add_string(&ret, &size, &alloc, "UUID") == -1) goto error;
+  if (add_string(&ret, &size, &alloc, get_blkid_tag(device, "UUID")) == -1)
+    goto error;
+  if (add_string_nodup(&ret, &size, &alloc, NULL) == -1) goto error;
+
+  return ret;
+error:
+  if (ret) free_strings(ret);
+  return NULL;
+}
+
+char **
+do_blkid(const char *device)
+{
+  int r;
+  char *out = NULL, *err = NULL;
+  char **lines = NULL;
+
+  char **ret = NULL;
+  int size = 0, alloc = 0;
+  int blkid_has_p_opt;
+
+  if ((blkid_has_p_opt = test_blkid_p_opt()) == -1)
+    return NULL;
+  else if (blkid_has_p_opt)
+    return blkid_with_p_opt(device);
+  else
+    return blkid_without_p_opt(device);
+}