Remove signal handling from LUKS keyencryption and simplify code.

[platform/upstream/cryptsetup.git] / lib / utils_loop.c

diff --git a/lib/utils_loop.c b/lib/utils_loop.c
index d628470..2fc46cd 100644 (file)
--- a/lib/utils_loop.c
+++ b/lib/utils_loop.c
@@ -1,7 +1,7 @@
 /*
  * loopback block device utilities
  *
- * Copyright (C) 2011, Red Hat, Inc. All rights reserved.
+ * Copyright (C) 2011-2012, Red Hat, Inc. All rights reserved.
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -14,7 +14,7 @@
  *
  * 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 <string.h>
@@ -22,13 +22,25 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <errno.h>
+#include <limits.h>
 #include <sys/ioctl.h>
 #include <sys/stat.h>
+#include <sys/types.h>
 #include <linux/loop.h>
 
 #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
+
+static char *crypt_loop_get_device_old(void)
 {
        char dev[20];
        int i, loop_fd;
@@ -55,6 +67,32 @@ char *crypt_loop_get_device(void)
        return NULL;
 }
 
+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(const char *loop, const char *file, int offset,
                      int autoclear, int *readonly)
 {
@@ -62,7 +100,7 @@ int crypt_loop_attach(const char *loop, const char *file, int offset,
        int loop_fd = -1, file_fd = -1, r = 1;
 
        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);
        }
@@ -120,7 +158,7 @@ int crypt_loop_detach(const char *loop)
        return r;
 }
 
-char *crypt_loop_backing_file(const char *loop)
+static char *_ioctl_backing_file(const char *loop)
 {
        struct loop_info64 lo64 = {0};
        int loop_fd;
@@ -142,6 +180,38 @@ char *crypt_loop_backing_file(const char *loop)
        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 = _sysfs_backing_file(loop);
+       return bf ?: _ioctl_backing_file(loop);
+}
+
 int crypt_loop_device(const char *loop)
 {
        struct stat st;