/* 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
#include <stdio.h>
#include <stdlib.h>
+#include <inttypes.h>
#include <string.h>
#include <fcntl.h>
#include <unistd.h>
#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_WRONLY);
+ fd = open (device, O_RDWR);
if (fd == -1) {
reply_with_perror ("%s", device);
return -1;
}
- memset (buf, 0, sizeof buf);
+ 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;
+
+ int fd = open (device, O_RDWR);
+ if (fd == -1) {
+ reply_with_perror ("%s", device);
+ return -1;
+ }
+
+ 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;
+ }
+
+ 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;
+
+ 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;
- int err = 0;
- int saved_errno = 0;
- for (i = 0; i < 32; ++i)
- if (write (fd, buf, sizeof buf) != sizeof buf) {
- saved_errno = errno;
- err = -1;
+ 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;
+ }
- if (close (fd) && saved_errno == 0) {
- saved_errno = errno;
- err = -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;
}
- if (saved_errno)
- errno = saved_errno;
- return err;
+ return 1;
}