[Qemu-devel] [PATCH 1/4] block: Change bdrv_get_encrypted_filename()

[Max Reitz <mreitz@redhat.com>]

Instead of returning a pointer to the filename, copy it into a buffer
specified by the caller. While adapting the callers accordingly, this
patch also fixes them apparently ignoring that this function's return
value may be NULL.

Signed-off-by: Max Reitz <mreitz@redhat.com>
---
 block.c               | 20 ++++++++++++++------
 blockdev.c            |  4 +++-
 include/block/block.h |  2 +-
 monitor.c             |  7 +++++--
 qmp.c                 |  4 +++-
 5 files changed, 26 insertions(+), 11 deletions(-)

diff --git a/block.c b/block.c
index a2fa1e1..4cf7620 100644
--- a/block.c
+++ b/block.c
@@ -4185,14 +4185,22 @@ int bdrv_is_allocated_above(BlockDriverState *top,
     return 0;
 }
 
-const char *bdrv_get_encrypted_filename(BlockDriverState *bs)
+char *bdrv_get_encrypted_filename(BlockDriverState *bs, char *dest, size_t sz)
 {
-    if (bs->backing_hd && bs->backing_hd->encrypted)
-        return bs->backing_file;
-    else if (bs->encrypted)
-        return bs->filename;
-    else
+    if (sz > INT_MAX) {
+        sz = INT_MAX;
+    }
+
+    if (bs->backing_hd && bs->backing_hd->encrypted) {
+        pstrcpy(dest, sz, bs->backing_file);
+        return dest;
+    } else if (bs->encrypted) {
+        pstrcpy(dest, sz, bs->filename);
+        return dest;
+    } else {
+        dest[0] = '\0';
         return NULL;
+    }
 }
 
 void bdrv_get_backing_filename(BlockDriverState *bs,
diff --git a/blockdev.c b/blockdev.c
index 450f95c..aed0519 100644
--- a/blockdev.c
+++ b/blockdev.c
@@ -1616,8 +1616,10 @@ static void qmp_bdrv_open_encrypted(BlockDriverState *bs, const char *filename,
                 error_set(errp, QERR_INVALID_PASSWORD);
             }
         } else {
+            char enc_filename[PATH_MAX];
+            bdrv_get_encrypted_filename(bs, enc_filename, sizeof(enc_filename));
             error_set(errp, QERR_DEVICE_ENCRYPTED, bdrv_get_device_name(bs),
-                      bdrv_get_encrypted_filename(bs));
+                      enc_filename);
         }
     } else if (password) {
         error_set(errp, QERR_DEVICE_NOT_ENCRYPTED, bdrv_get_device_name(bs));
diff --git a/include/block/block.h b/include/block/block.h
index 3318f0d..c6e82f3 100644
--- a/include/block/block.h
+++ b/include/block/block.h
@@ -429,7 +429,7 @@ void bdrv_round_to_clusters(BlockDriverState *bs,
                             int64_t *cluster_sector_num,
                             int *cluster_nb_sectors);
 
-const char *bdrv_get_encrypted_filename(BlockDriverState *bs);
+char *bdrv_get_encrypted_filename(BlockDriverState *bs, char *dest, size_t sz);
 void bdrv_get_backing_filename(BlockDriverState *bs,
                                char *filename, int filename_size);
 void bdrv_get_full_backing_filename(BlockDriverState *bs,
diff --git a/monitor.c b/monitor.c
index 667efb7..217d91e 100644
--- a/monitor.c
+++ b/monitor.c
@@ -5382,6 +5382,7 @@ int monitor_read_bdrv_key_start(Monitor *mon, BlockDriverState *bs,
                                 BlockDriverCompletionFunc *completion_cb,
                                 void *opaque)
 {
+    char enc_filename[PATH_MAX];
     int err;
 
     if (!bdrv_key_required(bs)) {
@@ -5390,14 +5391,16 @@ int monitor_read_bdrv_key_start(Monitor *mon, BlockDriverState *bs,
         return 0;
     }
 
+    bdrv_get_encrypted_filename(bs, enc_filename, sizeof(enc_filename));
+
     if (monitor_ctrl_mode(mon)) {
         qerror_report(QERR_DEVICE_ENCRYPTED, bdrv_get_device_name(bs),
-                      bdrv_get_encrypted_filename(bs));
+                      enc_filename);
         return -1;
     }
 
     monitor_printf(mon, "%s (%s) is encrypted.\n", bdrv_get_device_name(bs),
-                   bdrv_get_encrypted_filename(bs));
+                   enc_filename);
 
     mon->password_completion_cb = completion_cb;
     mon->password_opaque = opaque;
diff --git a/qmp.c b/qmp.c
index c6767c4..f8ca3d1 100644
--- a/qmp.c
+++ b/qmp.c
@@ -164,9 +164,11 @@ void qmp_cont(Error **errp)
     }
     for (bs = bdrv_next(NULL); bs; bs = bdrv_next(bs)) {
         if (bdrv_key_required(bs)) {
+            char enc_filename[PATH_MAX];
+            bdrv_get_encrypted_filename(bs, enc_filename, sizeof(enc_filename));
             error_set(errp, QERR_DEVICE_ENCRYPTED,
                       bdrv_get_device_name(bs),
-                      bdrv_get_encrypted_filename(bs));
+                      enc_filename);
             return;
         }
     }
-- 
2.1.0