X-Git-Url: http://git.annexia.org/?a=blobdiff_plain;f=daemon%2Fzero.c;h=67112d83825fd738ba4f31226bc4a7a053674a89;hb=8bc6e9d6a89672bbe1e7469774abe889354deb67;hp=ce45ae233c91dfa5ac6be33b699bb759c37f9021;hpb=84fc760439e82e6b3616abd0d1f9bd7d7eb01ec0;p=libguestfs.git

diff --git a/daemon/zero.c b/daemon/zero.c
index ce45ae2..67112d8 100644
--- a/daemon/zero.c
+++ b/daemon/zero.c
@@ -1,5 +1,5 @@
 /* libguestfs - the guestfsd daemon
- * Copyright (C) 2009 Red Hat Inc.
+ * Copyright (C) 2009-2011 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
@@ -13,13 +13,14 @@
  *
  * 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>
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <inttypes.h>
 #include <string.h>
 #include <fcntl.h>
 #include <unistd.h>
@@ -27,24 +28,176 @@
 #include "daemon.h"
 #include "actions.h"
 
+static const char zero_buf[4096];
+
 int
 do_zero (const char *device)
 {
-  int fd, i;
-  char buf[4096];
+  char buf[sizeof zero_buf];
+  int fd;
+  size_t i, offset;
+
+  fd = open (device, O_RDWR);
+  if (fd == -1) {
+    reply_with_perror ("%s", device);
+    return -1;
+  }
+
+  for (i = 0; i < 32; ++i) {
+    offset = i * sizeof zero_buf;
+
+    /* Check if the block is already zero before overwriting it. */
+    if (pread (fd, buf, sizeof buf, offset) != sizeof buf) {
+      reply_with_perror ("pread: %s", device);
+      close (fd);
+      return -1;
+    }
+
+    if (!is_zero (buf, sizeof buf)) {
+      if (pwrite (fd, zero_buf, sizeof zero_buf, offset) != sizeof zero_buf) {
+        reply_with_perror ("pwrite: %s", device);
+        close (fd);
+        return -1;
+      }
+    }
+
+    notify_progress ((uint64_t) i, 32);
+  }
+
+  if (close (fd) == -1) {
+    reply_with_perror ("close: %s", device);
+    return -1;
+  }
+
+  return 0;
+}
+
+int
+do_zero_device (const char *device)
+{
+  int64_t ssize = do_blockdev_getsize64 (device);
+  if (ssize == -1)
+    return -1;
+  uint64_t size = (uint64_t) ssize;
 
-  fd = open (device, O_WRONLY);
+  int fd = open (device, O_RDWR);
   if (fd == -1) {
     reply_with_perror ("%s", device);
     return -1;
   }
 
-  memset (buf, 0, sizeof buf);
+  char buf[sizeof zero_buf];
+
+  uint64_t pos = 0;
+
+  while (pos < size) {
+    uint64_t n64 = size - pos;
+    size_t n;
+    if (n64 > sizeof buf)
+      n = sizeof buf;
+    else
+      n = (size_t) n64; /* safe because of if condition */
+
+    /* Check if the block is already zero before overwriting it. */
+    ssize_t r;
+    r = pread (fd, buf, n, pos);
+    if (r == -1) {
+      reply_with_perror ("pread: %s at offset %" PRIu64, device, pos);
+      close (fd);
+      return -1;
+    }
 
-  for (i = 0; i < 32; ++i)
-    (void) write (fd, buf, sizeof buf);
+    if (!is_zero (buf, sizeof buf)) {
+      r = pwrite (fd, zero_buf, n, pos);
+      if (r == -1) {
+        reply_with_perror ("pwrite: %s (with %" PRId64 " bytes left to write)",
+                           device, size);
+        close (fd);
+        return -1;
+      }
+      pos += r;
+    }
+    else
+      pos += n;
 
-  close (fd);
+    notify_progress (pos, size);
+  }
+
+  if (close (fd) == -1) {
+    reply_with_perror ("close: %s", device);
+    return -1;
+  }
 
   return 0;
 }
+
+int
+do_is_zero (const char *path)
+{
+  int fd;
+  char buf[1024*1024];
+  ssize_t r;
+
+  CHROOT_IN;
+  fd = open (path, O_RDONLY);
+  CHROOT_OUT;
+
+  if (fd == -1) {
+    reply_with_perror ("open: %s", path);
+    return -1;
+  }
+
+  while ((r = read (fd, buf, sizeof buf)) > 0) {
+    if (!is_zero (buf, r)) {
+      close (fd);
+      return 0;
+    }
+  }
+
+  if (r == -1) {
+    reply_with_perror ("read: %s", path);
+    close (fd);
+    return -1;
+  }
+
+  if (close (fd) == -1) {
+    reply_with_perror ("close: %s", path);
+    return -1;
+  }
+
+  return 1;
+}
+
+int
+do_is_zero_device (const char *device)
+{
+  int fd;
+  char buf[1024*1024];
+  ssize_t r;
+
+  fd = open (device, O_RDONLY);
+  if (fd == -1) {
+    reply_with_perror ("open: %s", device);
+    return -1;
+  }
+
+  while ((r = read (fd, buf, sizeof buf)) > 0) {
+    if (!is_zero (buf, r)) {
+      close (fd);
+      return 0;
+    }
+  }
+
+  if (r == -1) {
+    reply_with_perror ("read: %s", device);
+    close (fd);
+    return -1;
+  }
+
+  if (close (fd) == -1) {
+    reply_with_perror ("close: %s", device);
+    return -1;
+  }
+
+  return 1;
+}