Added 'equal' command to compare files.

daemon/Makefile.am

@@ -23,6 +23,7 @@ guestfsd_SOURCES = \
 	augeas.c \
 	blockdev.c \
 	checksum.c \
+	cmp.c \
 	command.c \
 	cpmv.c \
 	daemon.h \

daemon/cmp.c

@@ -0,0 +1,74 @@
+/* libguestfs - the guestfsd daemon
+ * Copyright (C) 2009 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., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <config.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#include "daemon.h"
+#include "actions.h"
+
+int
+do_equal (const char *file1, const char *file2)
+{
+  char *file1buf, *file2buf;
+  int file1len, file2len;
+  char *err;
+  int r;
+
+  NEED_ROOT (-1);
+  ABS_PATH (file1, -1);
+  ABS_PATH (file2, -1);
+
+  file1len = strlen (file1) + 32;
+  file1buf = malloc (file1len);
+  if (file1buf == NULL) {
+    reply_with_perror ("malloc");
+    return -1;
+  }
+
+  file2len = strlen (file2) + 32;
+  file2buf = malloc (file2len);
+  if (file2buf == NULL) {
+    reply_with_perror ("malloc");
+    free (file1buf);
+    return -1;
+  }
+
+  snprintf (file1buf, file1len, "/sysroot%s", file1);
+  snprintf (file2buf, file2len, "/sysroot%s", file2);
+
+  r = commandr (NULL, &err, "cmp", "-s", file1buf, file2buf, NULL);
+
+  free (file1buf);
+  free (file2buf);
+
+  if (r == -1 || r > 1) {
+    reply_with_error ("cmp: %s", err);
+    free (err);
+    return -1;
+  }
+
+  free (err);
+
+  return r == 0;
+}

src/generator.ml

@@ -1776,6 +1776,24 @@ the qemu subprocess.  Calling this function checks that the
 daemon responds to the ping message, without affecting the daemon
 or attached block device(s) in any other way.");
 
+  ("equal", (RBool "equality", [String "file1"; String "file2"]), 93, [],
+   [InitBasicFS, TestOutputTrue (
+      [["write_file"; "/file1"; "contents of a file"; "0"];
+       ["cp"; "/file1"; "/file2"];
+       ["equal"; "/file1"; "/file2"]]);
+    InitBasicFS, TestOutputFalse (
+      [["write_file"; "/file1"; "contents of a file"; "0"];
+       ["write_file"; "/file2"; "contents of another file"; "0"];
+       ["equal"; "/file1"; "/file2"]]);
+    InitBasicFS, TestLastFail (
+      [["equal"; "/file1"; "/file2"]])],
+   "test if two files have equal contents",
+   "\
+This compares the two files C<file1> and C<file2> and returns
+true if their content is exactly equal, or false otherwise.
+
+The external L<cmp(1)> program is used for the comparison.");
+
 ]
 
 let all_functions = non_daemon_functions @ daemon_functions