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/* libguestfs
* Copyright (C) 2012 Red Hat Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2 of the License, or (at your option) any later version.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; 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 <stdint.h>
#include <inttypes.h>
#include <limits.h>
#include <fcntl.h>
#include <unistd.h>
#include <sys/types.h>
#include <sys/wait.h>
#include "guestfs.h"
#include "guestfs-internal.h"
#include "guestfs-internal-actions.h"
#include "guestfs_protocol.h"
static int run_qemu_img_info (guestfs_h *g, const char *filename, cmd_stdout_callback cb, void *data);
/* NB: For security reasons, the check_* callbacks MUST bail
* after seeing the first line that matches /^backing file: /. See:
* https://lists.gnu.org/archive/html/qemu-devel/2012-09/msg00137.html
* Eventually we should use the JSON output of qemu-img info.
*/
struct check_data {
int stop, failed;
union {
char *ret;
int reti;
int64_t reti64;
};
};
static void check_disk_format (guestfs_h *g, void *data, const char *line, size_t len);
static void check_disk_virtual_size (guestfs_h *g, void *data, const char *line, size_t len);
static void check_disk_has_backing_file (guestfs_h *g, void *data, const char *line, size_t len);
char *
guestfs__disk_format (guestfs_h *g, const char *filename)
{
struct check_data data;
memset (&data, 0, sizeof data);
if (run_qemu_img_info (g, filename, check_disk_format, &data) == -1) {
free (data.ret);
return NULL;
}
if (data.ret == NULL)
data.ret = safe_strdup (g, "unknown");
return data.ret;
}
static void
check_disk_format (guestfs_h *g, void *datav, const char *line, size_t len)
{
struct check_data *data = datav;
const char *p;
if (data->stop)
return;
if (STRPREFIX (line, "backing file: ")) {
data->stop = 1;
return;
}
if (STRPREFIX (line, "file format: ")) {
p = &line[13];
data->ret = safe_strdup (g, p);
data->stop = 1;
}
}
int64_t
guestfs__disk_virtual_size (guestfs_h *g, const char *filename)
{
struct check_data data;
memset (&data, 0, sizeof data);
if (run_qemu_img_info (g, filename, check_disk_virtual_size, &data) == -1)
return -1;
if (data.failed)
error (g, _("%s: cannot detect virtual size of disk image"), filename);
return data.reti64;
}
static void
check_disk_virtual_size (guestfs_h *g, void *datav,
const char *line, size_t len)
{
struct check_data *data = datav;
const char *p;
if (data->stop)
return;
if (STRPREFIX (line, "backing file: ")) {
data->stop = 1;
return;
}
if (STRPREFIX (line, "virtual size: ")) {
/* "virtual size: 500M (524288000 bytes)\n" */
p = &line[14];
p = strchr (p, ' ');
if (!p || p[1] != '(' || sscanf (&p[2], "%" SCNi64, &data->reti64) != 1)
data->failed = 1;
data->stop = 1;
}
}
int
guestfs__disk_has_backing_file (guestfs_h *g, const char *filename)
{
struct check_data data;
memset (&data, 0, sizeof data);
if (run_qemu_img_info (g, filename, check_disk_has_backing_file, &data) == -1)
return -1;
return data.reti;
}
static void
check_disk_has_backing_file (guestfs_h *g, void *datav,
const char *line, size_t len)
{
struct check_data *data = datav;
if (data->stop)
return;
if (STRPREFIX (line, "backing file: ")) {
data->reti = 1;
data->stop = 1;
}
}
static int
run_qemu_img_info (guestfs_h *g, const char *filename,
cmd_stdout_callback fn, void *data)
{
char *abs_filename = NULL;
char *safe_filename = NULL;
struct command *cmd;
int r;
if (guestfs___lazy_make_tmpdir (g) == -1)
return -1;
safe_filename = safe_asprintf (g, "%s/format.%d", g->tmpdir, ++g->unique);
/* 'filename' must be an absolute path so we can link to it. */
abs_filename = realpath (filename, NULL);
if (abs_filename == NULL) {
perrorf (g, "realpath");
goto error;
}
if (symlink (abs_filename, safe_filename) == -1) {
perrorf (g, "symlink");
goto error;
}
cmd = guestfs___new_command (g);
guestfs___cmd_add_arg (cmd, "qemu-img");
guestfs___cmd_add_arg (cmd, "info");
guestfs___cmd_add_arg (cmd, safe_filename);
guestfs___cmd_set_stdout_callback (cmd, fn, data, 0);
r = guestfs___cmd_run (cmd);
guestfs___cmd_close (cmd);
if (r == -1)
goto error;
if (!WIFEXITED (r) || WEXITSTATUS (r) != 0) {
error (g, _("qemu-img: %s: child process failed"), filename);
goto error;
}
free (safe_filename);
free (abs_filename);
return 0;
error:
free (safe_filename);
free (abs_filename);
return -1;
}
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