New API: mksquashfs

Introduce a new API to create a new squashfs filesystem out of a path
in the guest.  It can be configured to exclude paths based on patterns,
and to select which compression use for the filesystem.

The advantage of running mksquashfs directly in the appliance is that
ownerships are properly saved, as opposed to tar_out + local untar.

appliance/packagelist.in

@@ -151,6 +151,7 @@ ifelse(SUSE,1,
   ntfsprogs
   ntfs-3g
   reiserfs
+  squashfs
   systemd
   vim
   xz
@@ -253,6 +254,7 @@ rsync
 scrub
 sed
 sleuthkit
+squashfs-tools
 strace
 syslinux
 tar

daemon/Makefile.am

@@ -138,6 +138,7 @@ guestfsd_SOURCES = \
 	sh.c \
 	sleep.c \
 	sleuthkit.c \
+	squashfs.c \
 	stat.c \
 	statvfs.c \
 	strings.c \

daemon/squashfs.c

@@ -0,0 +1,150 @@
+/* libguestfs - the guestfsd daemon
+ * Copyright (C) 2017 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
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include "daemon.h"
+#include "actions.h"
+#include "optgroups.h"
+
+#define MAX_ARGS 64
+
+GUESTFSD_EXT_CMD(str_mksquashfs, mksquashfs);
+
+int
+optgroup_squashfs_available (void)
+{
+  return prog_exists (str_mksquashfs);
+}
+
+/* Takes optional arguments, consult optargs_bitmask. */
+int
+do_mksquashfs (const char *path, const char *compress, char *const *excludes)
+{
+  CLEANUP_FREE char *buf = NULL;
+  CLEANUP_UNLINK_FREE char *tmpfile = NULL;
+  CLEANUP_UNLINK_FREE char *exclude_from_file = NULL;
+  CLEANUP_FREE char *err = NULL;
+  CLEANUP_FREE char *buffer = NULL;
+  int r;
+  const char *argv[MAX_ARGS];
+  size_t i = 0;
+  int fd;
+  FILE *fp;
+
+  buf = sysroot_path (path);
+  if (buf == NULL) {
+    reply_with_perror ("malloc/sysroot_path");
+    return -1;
+  }
+
+  /* /var/tmp is used instead of /tmp, as /tmp is mounted as tmpfs
+   * and thus a newly created filesystem might not fit in memory.
+   */
+  tmpfile = strdup ("/var/tmp/squashfs.XXXXXX");
+  if (tmpfile == NULL) {
+    reply_with_perror ("strdup");
+    return -1;
+  }
+
+  fd = mkstemp (tmpfile);
+  if (fd == -1) {
+    reply_with_perror ("mkstemp");
+    return -1;
+  }
+  close (fd);
+
+  buffer = malloc (GUESTFS_MAX_CHUNK_SIZE);
+  if (buffer == NULL) {
+    reply_with_perror ("malloc/buffer");
+    return -1;
+  }
+
+  ADD_ARG (argv, i, str_mksquashfs);
+  ADD_ARG (argv, i, buf);
+  ADD_ARG (argv, i, tmpfile);
+  ADD_ARG (argv, i, "-noappend");
+  ADD_ARG (argv, i, "-root-becomes");
+  ADD_ARG (argv, i, buf);
+  ADD_ARG (argv, i, "-wildcards");
+  ADD_ARG (argv, i, "-no-recovery");
+
+  if (optargs_bitmask & GUESTFS_MKSQUASHFS_COMPRESS_BITMASK) {
+    ADD_ARG (argv, i, "-comp");
+    ADD_ARG (argv, i, compress);
+  }
+
+  if (optargs_bitmask & GUESTFS_MKSQUASHFS_EXCLUDES_BITMASK) {
+    exclude_from_file = make_exclude_from_file ("mksquashfs", excludes);
+    if (!exclude_from_file)
+      return -1;
+
+    ADD_ARG (argv, i, "-ef");
+    ADD_ARG (argv, i, exclude_from_file);
+  }
+
+  ADD_ARG (argv, i, NULL);
+
+  r = commandv (NULL, &err, argv);
+  if (r == -1) {
+    reply_with_error ("%s: %s", path, err);
+    return -1;
+  }
+
+  fp = fopen (tmpfile, "r");
+  if (fp == NULL) {
+    reply_with_perror ("%s", tmpfile);
+    return -1;
+  }
+
+  /* Now we must send the reply message, before the file contents.  After
+   * this there is no opportunity in the protocol to send any error
+   * message back.  Instead we can only cancel the transfer.
+   */
+  reply (NULL, NULL);
+
+  while ((r = fread (buffer, 1, GUESTFS_MAX_CHUNK_SIZE, fp)) > 0) {
+    if (send_file_write (buffer, r) < 0) {
+      fclose (fp);
+      return -1;
+    }
+  }
+
+  if (ferror (fp)) {
+    fprintf (stderr, "fread: %s: %m\n", tmpfile);
+    send_file_end (1);		/* Cancel. */
+    fclose (fp);
+    return -1;
+  }
+
+  if (fclose (fp) != 0) {
+    fprintf (stderr, "fclose: %s: %m\n", tmpfile);
+    send_file_end (1);		/* Cancel. */
+    return -1;
+  }
+
+  if (send_file_end (0))	/* Normal end of file. */
+    return -1;
+
+  return 0;
+}

generator/actions.ml

@@ -13280,6 +13280,35 @@ is removed." };
     shortdesc = "search the entries associated to the given inode";
     longdesc = "Internal function for find_inode." };
 
+  { defaults with
+    name = "mksquashfs"; added = (1, 35, 25);
+    style = RErr, [Pathname "path"; FileOut "filename"], [OString "compress"; OStringList "excludes"];
+    proc_nr = Some 471;
+    optional = Some "squashfs";
+    cancellable = true;
+    shortdesc = "create a squashfs filesystem";
+    longdesc = "\
+Create a squashfs filesystem for the specified C<path>.
+
+The optional C<compress> flag controls compression.  If not given,
+then the output compressed using C<gzip>.  Otherwise one
+of the following strings may be given to select the compression
+type of the squashfs: C<gzip>, C<lzma>, C<lzo>, C<lz4>, C<xz>.
+
+The other optional arguments are:
+
+=over 4
+
+=item C<excludes>
+
+A list of wildcards.  Files are excluded if they match any of the
+wildcards.
+
+=back
+
+Please note that this API may fail when used to compress directories
+with large files, such as the resulting squashfs will be over 3GB big." };
+
 ]
 
 (* Non-API meta-commands available only in guestfish.

gobject/Makefile.inc

@@ -89,6 +89,7 @@ guestfs_gobject_headers= \
   include/guestfs-gobject/optargs-mke2fs.h \
   include/guestfs-gobject/optargs-mkfs.h \
   include/guestfs-gobject/optargs-mkfs_btrfs.h \
+  include/guestfs-gobject/optargs-mksquashfs.h \
   include/guestfs-gobject/optargs-mkswap.h \
   include/guestfs-gobject/optargs-mktemp.h \
   include/guestfs-gobject/optargs-mount_9p.h \
@@ -180,6 +181,7 @@ guestfs_gobject_sources= \
   src/optargs-mke2fs.c \
   src/optargs-mkfs.c \
   src/optargs-mkfs_btrfs.c \
+  src/optargs-mksquashfs.c \
   src/optargs-mkswap.c \
   src/optargs-mktemp.c \
   src/optargs-mount_9p.c \

lib/MAX_PROC_NR

@@ -1 +1 @@
-470
+471