/*
* loopback block device utilities
*
- * Copyright (C) 2011, Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2009-2020 Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2009-2020 Milan Broz
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
- * version 2 as published by the Free Software Foundation.
+ * 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
*
* 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
+#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include <unistd.h>
#include <fcntl.h>
#include <errno.h>
+#include <limits.h>
#include <sys/ioctl.h>
#include <sys/stat.h>
+#include <sys/types.h>
+#ifdef HAVE_SYS_SYSMACROS_H
+# include <sys/sysmacros.h> /* for major, minor */
+#endif
#include <linux/loop.h>
+#ifdef HAVE_SYS_SYSMACROS_H
+#include <sys/sysmacros.h> /* for major, minor */
+#endif
#include "utils_loop.h"
-char *crypt_loop_get_device(void)
+#define LOOP_DEV_MAJOR 7
+
+#ifndef LO_FLAGS_AUTOCLEAR
+#define LO_FLAGS_AUTOCLEAR 4
+#endif
+
+#ifndef LOOP_CTL_GET_FREE
+#define LOOP_CTL_GET_FREE 0x4C82
+#endif
+
+#ifndef LOOP_SET_CAPACITY
+#define LOOP_SET_CAPACITY 0x4C07
+#endif
+
+static char *crypt_loop_get_device_old(void)
{
char dev[20];
int i, loop_fd;
- struct stat st;
struct loop_info64 lo64 = {0};
for (i = 0; i < 256; i++) {
sprintf(dev, "/dev/loop%d", i);
- if (stat(dev, &st) || !S_ISBLK(st.st_mode))
- return NULL;
loop_fd = open(dev, O_RDONLY);
if (loop_fd < 0)
return NULL;
}
-int crypt_loop_attach(const char *loop, const char *file, int offset,
+static char *crypt_loop_get_device(void)
+{
+ char dev[64];
+ int i, loop_fd;
+ struct stat st;
+
+ loop_fd = open("/dev/loop-control", O_RDONLY);
+ if (loop_fd < 0)
+ return crypt_loop_get_device_old();
+
+ i = ioctl(loop_fd, LOOP_CTL_GET_FREE);
+ if (i < 0) {
+ close(loop_fd);
+ return NULL;
+ }
+ close(loop_fd);
+
+ if (sprintf(dev, "/dev/loop%d", i) < 0)
+ return NULL;
+
+ if (stat(dev, &st) || !S_ISBLK(st.st_mode))
+ return NULL;
+
+ return strdup(dev);
+}
+
+int crypt_loop_attach(char **loop, const char *file, int offset,
int autoclear, int *readonly)
{
struct loop_info64 lo64 = {0};
+ char *lo_file_name;
int loop_fd = -1, file_fd = -1, r = 1;
+ *loop = NULL;
+
file_fd = open(file, (*readonly ? O_RDONLY : O_RDWR) | O_EXCL);
- if (file_fd < 0 && errno == EROFS && !*readonly) {
+ if (file_fd < 0 && (errno == EROFS || errno == EACCES) && !*readonly) {
*readonly = 1;
file_fd = open(file, O_RDONLY | O_EXCL);
}
if (file_fd < 0)
goto out;
- loop_fd = open(loop, *readonly ? O_RDONLY : O_RDWR);
- if (loop_fd < 0)
- goto out;
+ while (loop_fd < 0) {
+ *loop = crypt_loop_get_device();
+ if (!*loop)
+ goto out;
- strncpy((char*)lo64.lo_file_name, file, LO_NAME_SIZE);
+ loop_fd = open(*loop, *readonly ? O_RDONLY : O_RDWR);
+ if (loop_fd < 0)
+ goto out;
+
+ if (ioctl(loop_fd, LOOP_SET_FD, file_fd) < 0) {
+ if (errno != EBUSY)
+ goto out;
+ free(*loop);
+ *loop = NULL;
+
+ close(loop_fd);
+ loop_fd = -1;
+ }
+ }
+
+ lo_file_name = (char*)lo64.lo_file_name;
+ lo_file_name[LO_NAME_SIZE-1] = '\0';
+ strncpy(lo_file_name, file, LO_NAME_SIZE-1);
lo64.lo_offset = offset;
if (autoclear)
lo64.lo_flags |= LO_FLAGS_AUTOCLEAR;
- if (ioctl(loop_fd, LOOP_SET_FD, file_fd) < 0)
- goto out;
-
if (ioctl(loop_fd, LOOP_SET_STATUS64, &lo64) < 0) {
(void)ioctl(loop_fd, LOOP_CLR_FD, 0);
goto out;
close(loop_fd);
if (file_fd >= 0)
close(file_fd);
+ if (r && *loop) {
+ free(*loop);
+ *loop = NULL;
+ }
return r ? -1 : loop_fd;
}
return r;
}
-char *crypt_loop_backing_file(const char *loop)
+int crypt_loop_resize(const char *loop)
+{
+ int loop_fd = -1, r = 1;
+
+ loop_fd = open(loop, O_RDONLY);
+ if (loop_fd < 0)
+ return 1;
+
+ if (!ioctl(loop_fd, LOOP_SET_CAPACITY, 0))
+ r = 0;
+
+ close(loop_fd);
+ return r;
+}
+
+static char *_ioctl_backing_file(const char *loop)
{
struct loop_info64 lo64 = {0};
int loop_fd;
return strdup((char*)lo64.lo_file_name);
}
+static char *_sysfs_backing_file(const char *loop)
+{
+ struct stat st;
+ char buf[PATH_MAX];
+ size_t len;
+ int fd;
+
+ if (stat(loop, &st) || !S_ISBLK(st.st_mode))
+ return NULL;
+
+ snprintf(buf, sizeof(buf), "/sys/dev/block/%d:%d/loop/backing_file",
+ major(st.st_rdev), minor(st.st_rdev));
+
+ fd = open(buf, O_RDONLY);
+ if (fd < 0)
+ return NULL;
+
+ len = read(fd, buf, PATH_MAX);
+ close(fd);
+ if (len < 2)
+ return NULL;
+
+ buf[len - 1] = '\0';
+ return strdup(buf);
+}
+
+char *crypt_loop_backing_file(const char *loop)
+{
+ char *bf;
+
+ if (!crypt_loop_device(loop))
+ return NULL;
+
+ bf = _sysfs_backing_file(loop);
+ return bf ?: _ioctl_backing_file(loop);
+}
+
int crypt_loop_device(const char *loop)
{
struct stat st;
projects / platform / upstream / cryptsetup.git / blobdiff