Check device exclusively.

diff --git a/src/crypt_reencrypt.c b/src/crypt_reencrypt.c
index 818c82f..642b804 100644 (file)
--- a/src/crypt_reencrypt.c
+++ b/src/crypt_reencrypt.c
@@ -101,7 +101,8 @@ int  MAGIC_L = 6;
 typedef enum {
        MAKE_UNUSABLE,
        MAKE_USABLE,
-       CHECK_UNUSABLE
+       CHECK_UNUSABLE,
+       CHECK_OPEN,
 } header_magic;
 
 __attribute__((format(printf, 5, 6)))
@@ -198,15 +199,27 @@ static int alignment(int fd)
        return alignment;
 }
 
-static int device_magic(struct reenc_ctx *rc, header_magic set_magic)
+static int device_check(struct reenc_ctx *rc, header_magic set_magic)
 {
        char *buf = NULL;
        int r, devfd;
        ssize_t s;
 
-       devfd = open(rc->device, O_RDWR | O_DIRECT);
-       if (devfd == -1)
-               return errno == EBUSY ? -EBUSY : -EINVAL;
+       devfd = open(rc->device, O_RDWR | O_EXCL | O_DIRECT);
+       if (devfd == -1) {
+               if (errno == EBUSY) {
+                       log_err(_("Cannot exclusively open %s, device in use.\n"),
+                               rc->device);
+                       return -EBUSY;
+               }
+               log_err(_("Cannot open device %s\n"), rc->device);
+               return -EINVAL;
+       }
+
+       if (set_magic == CHECK_OPEN) {
+               r = 0;
+               goto out;
+       }
 
        if (posix_memalign((void *)&buf, alignment(devfd), SECTOR_SIZE)) {
                log_err(_("Allocation of aligned memory failed.\n"));
@@ -790,7 +803,7 @@ static int initialize_uuid(struct reenc_ctx *rc)
                rc->device_uuid = strdup(crypt_get_uuid(cd));
        else
                /* Reencryption already in progress - magic header? */
-               r = device_magic(rc, CHECK_UNUSABLE);
+               r = device_check(rc, CHECK_UNUSABLE);
 
        crypt_free(cd);
        return r;
@@ -917,6 +930,9 @@ static int initialize_context(struct reenc_ctx *rc, const char *device)
        if (!(rc->device = strndup(device, PATH_MAX)))
                return -ENOMEM;
 
+       if (device_check(rc, CHECK_OPEN) < 0)
+               return -EINVAL;
+
        if (initialize_uuid(rc)) {
                log_err(_("Device %s is not a valid LUKS device.\n"), device);
                return -EINVAL;
@@ -998,7 +1014,7 @@ static int run_reencrypt(const char *device)
        if (!rc.in_progress) {
                if ((r = initialize_passphrase(&rc, rc.device)) ||
                    (r = backup_luks_headers(&rc)) ||
-                   (r = device_magic(&rc, MAKE_UNUSABLE)))
+                   (r = device_check(&rc, MAKE_UNUSABLE)))
                        goto out;
        } else {
                if ((r = initialize_passphrase(&rc, rc.header_file_new)))