[Qemu-devel] [PATCH] block/raw-posix: use a character device if a block device is given

[Christoph Egger <Christoph.Egger@amd.com>]

On NetBSD a userland process is better with the character device
interface. In addition, a block device can't be opened twice; if a Xen
backend opens it, qemu can't and vice-versa.

diff --git a/block/raw-posix.c b/block/raw-posix.c
index 6b72470..64dceb1 100644
--- a/block/raw-posix.c
+++ b/block/raw-posix.c
@@ -136,12 +143,55 @@ static int64_t raw_getlength(BlockDriverState *bs);
  static int cdrom_reopen(BlockDriverState *bs);
  #endif

+#if defined(__NetBSD__)
+static int raw_normalize_devicepath(const char **filename)
+{
+    static char namebuf[PATH_MAX];
+    const char *dp, *fname;
+    struct stat sb;
+
+    fname = *filename;
+    dp = strrchr(fname, '/');
+    if (lstat(fname, &sb) < 0) {
+        fprintf(stderr, "%s: stat failed: %s\n",
+            fname, strerror(errno));
+        return -errno;
+    }
+
+    if (!S_ISBLK(sb.st_mode)) {
+        return 0;
+    }
+
+    if (dp == NULL) {
+        snprintf(namebuf, PATH_MAX, "r%s", fname);
+    } else {
+        snprintf(namebuf, PATH_MAX, "%.*s/r%s",
+            (int)(dp - fname), fname, dp + 1);
+    }
+    fprintf(stderr, "%s is a block device", fname);
+    *filename = namebuf;
+    fprintf(stderr, ", using %s\n", *filename);
+
+    return 0;
+}
+#else
+static int raw_normalize_devicepath(const char **filename)
+{
+    return 0;
+}
+#endif
+
  static int raw_open_common(BlockDriverState *bs, const char *filename,
                             int bdrv_flags, int open_flags)
  {
      BDRVRawState *s = bs->opaque;
      int fd, ret;

+    ret = raw_normalize_devicepath(&filename);
+    if (ret != 0) {
+        return ret;
+    }
+
      s->open_flags = open_flags | O_BINARY;
      s->open_flags &= ~O_ACCMODE;
      if (bdrv_flags & BDRV_O_RDWR) {


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