New APIs for reading and writing ext2 file attributes and file generation.

The new APIs are:

  get-e2attrs: List ext2 file attributes of a file.
  set-e2attrs: Set or clear ext2 file attributes of a file.
  get-e2generation: Get ext2 file generation of a file.
  set-e2generation: Set ext2 file generation of a file.

These are implemented using the lsattr and chattr programs from
e2fsprogs.

TODO

@@ -51,8 +51,6 @@ Ideas for extra commands
     more mk*temp calls
 
   ext2 properties:
-    chattr
-    lsattr
     badblocks
     debugfs
     dumpe2fs

daemon/ext2.c

@@ -1,5 +1,5 @@
 /* libguestfs - the guestfsd daemon
- * Copyright (C) 2009 Red Hat Inc.
+ * Copyright (C) 2009-2012 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
@@ -694,3 +694,195 @@ do_tune2fs (const char *device, /* only required parameter */
   free (err);
   return 0;
 }
+
+static int
+compare_chars (const void *vc1, const void *vc2)
+{
+  char c1 = * (char *) vc1;
+  char c2 = * (char *) vc2;
+  return c1 - c2;
+}
+
+char *
+do_get_e2attrs (const char *filename)
+{
+  int r;
+  char *buf;
+  char *out, *err;
+  size_t i, j;
+
+  buf = sysroot_path (filename);
+  if (!buf) {
+    reply_with_perror ("malloc");
+    return NULL;
+  }
+
+  r = command (&out, &err, "lsattr", "-d", "--", buf, NULL);
+  free (buf);
+  if (r == -1) {
+    reply_with_error ("%s: %s: %s", "lsattr", filename, err);
+    free (err);
+    free (out);
+    return NULL;
+  }
+  free (err);
+
+  /* Output looks like:
+   * -------------e- filename
+   * Remove the dashes and return everything up to the space.
+   */
+  for (i = j = 0; out[j] != ' '; j++) {
+    if (out[j] != '-')
+      out[i++] = out[j];
+  }
+
+  out[i] = '\0';
+
+  /* Sort the output, mainly to make testing simpler. */
+  qsort (out, i, sizeof (char), compare_chars);
+
+  return out;
+}
+
+/* Takes optional arguments, consult optargs_bitmask. */
+int
+do_set_e2attrs (const char *filename, const char *attrs, int clear)
+{
+  int r;
+  char *buf;
+  char *err;
+  size_t i, j;
+  int lowers[26], uppers[26];
+  char attr_arg[26*2+1+1]; /* '+'/'-' + attrs + trailing '\0' */
+
+  if (!(optargs_bitmask & GUESTFS_SET_E2ATTRS_CLEAR_BITMASK))
+    attr_arg[0] = '+';
+  else if (!clear)
+    attr_arg[0] = '+';
+  else
+    attr_arg[0] = '-';
+  j = 1;
+
+  /* You can't write "chattr - file", so we have to just return if
+   * the string is empty.
+   */
+  if (STREQ (attrs, ""))
+    return 0;
+
+  /* Valid attrs are all lower or upper case ASCII letters.  Check
+   * this and that there are no duplicates.
+   */
+  memset (lowers, 0, sizeof lowers);
+  memset (uppers, 0, sizeof uppers);
+  for (; *attrs; attrs++) {
+    /* These are reserved by the chattr program for command line flags. */
+    if (*attrs == 'R' || *attrs == 'V' || *attrs == 'f' || *attrs == 'v') {
+      reply_with_error ("bad file attribute '%c'", *attrs);
+      return -1;
+    }
+    else if (*attrs >= 'a' && *attrs <= 'z') {
+      i = *attrs - 'a';
+      if (lowers[i] > 0)
+        goto error_duplicate;
+      lowers[i]++;
+      attr_arg[j++] = *attrs;
+    }
+    else if (*attrs >= 'A' && *attrs <= 'Z') {
+      i = *attrs - 'A';
+      if (uppers[i] > 0) {
+      error_duplicate:
+        reply_with_error ("duplicate file attribute '%c'", *attrs);
+        return -1;
+      }
+      uppers[i]++;
+      attr_arg[j++] = *attrs;
+    }
+    else {
+      reply_with_error ("unknown file attribute '%c'", *attrs);
+      return -1;
+    }
+  }
+
+  attr_arg[j] = '\0';
+
+  buf = sysroot_path (filename);
+  if (!buf) {
+    reply_with_perror ("malloc");
+    return -1;
+  }
+
+  r = command (NULL, &err, "chattr", attr_arg, "--", buf, NULL);
+  free (buf);
+  if (r == -1) {
+    reply_with_error ("%s: %s: %s", "chattr", filename, err);
+    free (err);
+    return -1;
+  }
+  free (err);
+
+  return 0;
+}
+
+int64_t
+do_get_e2generation (const char *filename)
+{
+  int r;
+  char *buf;
+  char *out, *err;
+  int64_t ret;
+
+  buf = sysroot_path (filename);
+  if (!buf) {
+    reply_with_perror ("malloc");
+    return -1;
+  }
+
+  r = command (&out, &err, "lsattr", "-dv", "--", buf, NULL);
+  free (buf);
+  if (r == -1) {
+    reply_with_error ("%s: %s: %s", "lsattr", filename, err);
+    free (err);
+    free (out);
+    return -1;
+  }
+  free (err);
+
+  if (sscanf (out, "%" SCNu64, &ret) != 1) {
+    reply_with_error ("cannot parse output from '%s' command: %s",
+                      "lsattr", out);
+    free (out);
+    return -1;
+  }
+  free (out);
+
+  return ret;
+}
+
+int
+do_set_e2generation (const char *filename, int64_t generation)
+{
+  int r;
+  char *buf;
+  char *err;
+  char generation_str[64];
+
+  buf = sysroot_path (filename);
+  if (!buf) {
+    reply_with_perror ("malloc");
+    return -1;
+  }
+
+  snprintf (generation_str, sizeof generation_str,
+            "%" PRIu64, (uint64_t) generation);
+
+  r = command (NULL, &err, "chattr", "-v", generation_str, "--", buf, NULL);
+  free (buf);
+  if (r == -1) {
+    reply_with_error ("%s: %s: %s", "chattr", filename, err);
+    free (err);
+    return -1;
+  }
+  free (err);
+
+  return 0;
+}

generator/generator_actions.ml

@@ -6940,6 +6940,199 @@ For more information on the optional arguments, see L<mkfs.btrfs(8)>.
 
 To create general filesystems, use C<guestfs_mkfs_opts>.");
 
+  ("get_e2attrs", (RString "attrs", [Pathname "file"], []), 318, [],
+   [InitScratchFS, Always, TestOutput (
+     [["touch"; "/e2attrs1"];
+      ["get_e2attrs"; "/e2attrs1"]], "");
+    InitScratchFS, Always, TestOutput (
+     [["touch"; "/e2attrs2"];
+      ["set_e2attrs"; "/e2attrs2"; "is"; "false"];
+      ["get_e2attrs"; "/e2attrs2"]], "is");
+    InitScratchFS, Always, TestOutput (
+     [["touch"; "/e2attrs3"];
+      ["set_e2attrs"; "/e2attrs3"; "is"; "false"];
+      ["set_e2attrs"; "/e2attrs3"; "i"; "true"];
+      ["get_e2attrs"; "/e2attrs3"]], "s");
+    InitScratchFS, Always, TestOutput (
+     [["touch"; "/e2attrs4"];
+      ["set_e2attrs"; "/e2attrs4"; "adst"; "false"];
+      ["set_e2attrs"; "/e2attrs4"; "iS"; "false"];
+      ["set_e2attrs"; "/e2attrs4"; "i"; "true"];
+      ["set_e2attrs"; "/e2attrs4"; "ad"; "true"];
+      ["set_e2attrs"; "/e2attrs4"; ""; "false"];
+      ["set_e2attrs"; "/e2attrs4"; ""; "true"];
+      ["get_e2attrs"; "/e2attrs4"]], "Sst");
+    InitScratchFS, Always, TestLastFail (
+     [["touch"; "/e2attrs5"];
+      ["set_e2attrs"; "/e2attrs5"; "R"; "false"]]);
+    InitScratchFS, Always, TestLastFail (
+     [["touch"; "/e2attrs6"];
+      ["set_e2attrs"; "/e2attrs6"; "v"; "false"]]);
+    InitScratchFS, Always, TestLastFail (
+     [["touch"; "/e2attrs7"];
+      ["set_e2attrs"; "/e2attrs7"; "aa"; "false"]]);
+    InitScratchFS, Always, TestLastFail (
+     [["touch"; "/e2attrs8"];
+      ["set_e2attrs"; "/e2attrs8"; "BabcdB"; "false"]])],
+   "get ext2 file attributes of a file",
+   "\
+This returns the file attributes associated with C<file>.
+
+The attributes are a set of bits associated with each
+inode which affect the behaviour of the file.  The attributes
+are returned as a string of letters (described below).  The
+string may be empty, indicating that no file attributes are
+set for this file.
+
+These attributes are only present when the file is located on
+an ext2/3/4 filesystem.  Using this call on other filesystem
+types will result in an error.
+
+The characters (file attributes) in the returned string are
+currently:
+
+=over 4
+
+=item 'A'
+
+When the file is accessed, its atime is not modified.
+
+=item 'a'
+
+The file is append-only.
+
+=item 'c'
+
+The file is compressed on-disk.
+
+=item 'D'
+
+(Directories only.)  Changes to this directory are written
+synchronously to disk.
+
+=item 'd'
+
+The file is not a candidate for backup (see L<dump(8)>).
+
+=item 'E'
+
+The file has compression errors.
+
+=item 'e'
+
+The file is using extents.
+
+=item 'h'
+
+The file is storing its blocks in units of the filesystem blocksize
+instead of sectors.
+
+=item 'I'
+
+(Directories only.)  The directory is using hashed trees.
+
+=item 'i'
+
+The file is immutable.  It cannot be modified, deleted or renamed.
+No link can be created to this file.
+
+=item 'j'
+
+The file is data-journaled.
+
+=item 's'
+
+When the file is deleted, all its blocks will be zeroed.
+
+=item 'S'
+
+Changes to this file are written synchronously to disk.
+
+=item 'T'
+
+(Directories only.)  This is a hint to the block allocator
+that subdirectories contained in this directory should be
+spread across blocks.  If not present, the block allocator
+will try to group subdirectories together.
+
+=item 't'
+
+For a file, this disables tail-merging.
+(Not used by upstream implementations of ext2.)
+
+=item 'u'
+
+When the file is deleted, its blocks will be saved, allowing
+the file to be undeleted.
+
+=item 'X'
+
+The raw contents of the compressed file may be accessed.
+
+=item 'Z'
+
+The compressed file is dirty.
+
+=back
+
+More file attributes may be added to this list later.  Not all
+file attributes may be set for all kinds of files.  For
+detailed information, consult the L<chattr(1)> man page.
+
+See also C<guestfs_set_e2attrs>.
+
+Don't confuse these attributes with extended attributes
+(see C<guestfs_getxattr>).");
+
+  ("set_e2attrs", (RErr, [Pathname "file"; String "attrs"], [OBool "clear"]), 319, [],
+   [] (* tested by get_e2attrs *),
+   "set ext2 file attributes of a file",
+   "\
+This sets or clears the file attributes C<attrs>
+associated with the inode C<file>.
+
+C<attrs> is a string of characters representing
+file attributes.  See C<guestfs_get_e2attrs> for a list of
+possible attributes.  Not all attributes can be changed.
+
+If optional boolean C<clear> is not present or false, then
+the C<attrs> listed are set in the inode.
+
+If C<clear> is true, then the C<attrs> listed are cleared
+in the inode.
+
+In both cases, other attributes not present in the C<attrs>
+string are left unchanged.
+
+These attributes are only present when the file is located on
+an ext2/3/4 filesystem.  Using this call on other filesystem
+types will result in an error.");
+
+  ("get_e2generation", (RInt64 "generation", [Pathname "file"], []), 320, [],
+   [InitScratchFS, Always, TestOutputInt (
+     [["touch"; "/e2generation"];
+      ["set_e2generation"; "/e2generation"; "123456"];
+      ["get_e2generation"; "/e2generation"]], 123456)],
+   "get ext2 file generation of a file",
+   "\
+This returns the ext2 file generation of a file.  The generation
+(which used to be called the \"version\") is a number associated
+with an inode.  This is most commonly used by NFS servers.
+
+The generation is only present when the file is located on
+an ext2/3/4 filesystem.  Using this call on other filesystem
+types will result in an error.
+
+See C<guestfs_set_e2generation>.");
+
+  ("set_e2generation", (RErr, [Pathname "file"; Int64 "generation"], []), 321, [],
+   [], (* tested by get_e2generation *)
+   "set ext2 file generation of a file",
+   "\
+This sets the ext2 file generation of a file.
+
+See C<guestfs_get_e2generation>.");
+
 ]
 
 let all_functions = non_daemon_functions @ daemon_functions

gobject/Makefile.inc

@@ -58,7 +58,8 @@ guestfs_gobject_headers=\
   guestfs-gobject-optargs-e2fsck.h \
   guestfs-gobject-optargs-ntfsfix.h \
   guestfs-gobject-optargs-ntfsclone_out.h \
-  guestfs-gobject-optargs-mkfs_btrfs.h
+  guestfs-gobject-optargs-mkfs_btrfs.h \
+  guestfs-gobject-optargs-set_e2attrs.h
 
 guestfs_gobject_sources=\
   guestfs-gobject-session.c \
@@ -98,4 +99,5 @@ guestfs_gobject_sources=\
   guestfs-gobject-optargs-e2fsck.c \
   guestfs-gobject-optargs-ntfsfix.c \
   guestfs-gobject-optargs-ntfsclone_out.c \
-  guestfs-gobject-optargs-mkfs_btrfs.c
+  guestfs-gobject-optargs-mkfs_btrfs.c \
+  guestfs-gobject-optargs-set_e2attrs.c

po/POTFILES.in

@@ -149,6 +149,7 @@ gobject/guestfs-gobject-optargs-mount_local.c
 gobject/guestfs-gobject-optargs-ntfsclone_out.c
 gobject/guestfs-gobject-optargs-ntfsfix.c
 gobject/guestfs-gobject-optargs-ntfsresize_opts.c
+gobject/guestfs-gobject-optargs-set_e2attrs.c
 gobject/guestfs-gobject-optargs-test0.c
 gobject/guestfs-gobject-optargs-tune2fs.c
 gobject/guestfs-gobject-optargs-umount_local.c

src/MAX_PROC_NR

@@ -1 +1 @@
-317
+321