[v5,06/10] qemu-nbd: allow specifying image as a set of options args

Commit Message

Daniel P. Berrangé Feb. 2, 2016, 12:57 p.m. UTC

Currently qemu-nbd allows an image filename to be passed on the
command line, but unless using the JSON format, it does not have
a way to set any options except the format eg

   qemu-nbd https://127.0.0.1/images/centos7.iso
   qemu-nbd /home/berrange/demo.qcow2

This adds a --image-opts arg that indicates that the positional
filename should be interpreted as a full option string, not
just a filename.

   qemu-nbd --image-opts driver=https,url=https://127.0.0.1/images,sslverify=off
   qemu-nbd --image-opts driver=file,filename=/home/berrange/demo.qcow2

This flag is mutually exclusive with the '-f' flag.

Signed-off-by: Daniel P. Berrange <[e-mail]>
---
 qemu-nbd.c | 42 +++++++++++++++++++++++++++++++++++++-----
 1 file changed, 37 insertions(+), 5 deletions(-)

Comments

Eric Blake Feb. 3, 2016, 3:47 p.m. UTC | #1

On 02/02/2016 05:57 AM, Daniel P. Berrange wrote:
> Currently qemu-nbd allows an image filename to be passed on the
> command line, but unless using the JSON format, it does not have
> a way to set any options except the format eg
> 
>    qemu-nbd https://127.0.0.1/images/centos7.iso
>    qemu-nbd /home/berrange/demo.qcow2
> 
> This adds a --image-opts arg that indicates that the positional
> filename should be interpreted as a full option string, not
> just a filename.
> 
>    qemu-nbd --image-opts driver=https,url=https://127.0.0.1/images,sslverify=off
>    qemu-nbd --image-opts driver=file,filename=/home/berrange/demo.qcow2
> 
> This flag is mutually exclusive with the '-f' flag.
> 
> Signed-off-by: Daniel P. Berrange <[e-mail]>
> ---
>  qemu-nbd.c | 42 +++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 37 insertions(+), 5 deletions(-)

Where is this new option documented? At a minimum, 'qemu-nbd --help'
should mention it. If later in the series, mention that in the commit
message.

> 
> diff --git a/qemu-nbd.c b/qemu-nbd.c
> index 0e019c1..ee91e47 100644
> --- a/qemu-nbd.c
> +++ b/qemu-nbd.c
> @@ -47,6 +47,7 @@
>  #define QEMU_NBD_OPT_DISCARD       3
>  #define QEMU_NBD_OPT_DETECT_ZEROES 4
>  #define QEMU_NBD_OPT_OBJECT        5
> +#define QEMU_NBD_OPT_IMAGE_OPTS    6

Churn here where 8/10 has to touch the same line; but I'm not sure
rearranging the series is worth the effort, so I don't mind it.

> @@ -724,13 +740,29 @@ int main(int argc, char **argv)
>      bdrv_init();
>      atexit(bdrv_close_all);

There's an earlier use of argv[optind] for the --disconnect option;
should that code be tweaked at all, or is it always safe for that path
to blindly open(name) without trying to parse options?

Patch

diff --git a/qemu-nbd.c b/qemu-nbd.c
index 0e019c1..ee91e47 100644
--- a/qemu-nbd.c
+++ b/qemu-nbd.c
@@ -47,6 +47,7 @@ 
 #define QEMU_NBD_OPT_DISCARD       3
 #define QEMU_NBD_OPT_DETECT_ZEROES 4
 #define QEMU_NBD_OPT_OBJECT        5
+#define QEMU_NBD_OPT_IMAGE_OPTS    6
 
 static NBDExport *exp;
 static int verbose;
@@ -380,6 +381,16 @@  static SocketAddress *nbd_build_socket_address(const char *sockpath,
 }
 
 
+static QemuOptsList file_opts = {
+    .name = "file",
+    .implied_opt_name = "file",
+    .head = QTAILQ_HEAD_INITIALIZER(file_opts.head),
+    .desc = {
+        /* no elements => accept any params */
+        { /* end of list */ }
+    },
+};
+
 static QemuOptsList qemu_object_opts = {
     .name = "object",
     .implied_opt_name = "qom-type",
@@ -428,6 +439,7 @@  int main(int argc, char **argv)
         { "persistent", 0, NULL, 't' },
         { "verbose", 0, NULL, 'v' },
         { "object", 1, NULL, QEMU_NBD_OPT_OBJECT },
+        { "image-opts", 0, NULL, QEMU_NBD_OPT_IMAGE_OPTS },
         { NULL, 0, NULL, 0 }
     };
     int ch;
@@ -445,6 +457,7 @@  int main(int argc, char **argv)
     Error *local_err = NULL;
     BlockdevDetectZeroesOptions detect_zeroes = BLOCKDEV_DETECT_ZEROES_OPTIONS_OFF;
     QDict *options = NULL;
+    bool imageOpts = false;
 
     /* The client thread uses SIGTERM to interrupt the server.  A signal
      * handler ensures that "qemu-nbd -v -c" exits with a nice status code.
@@ -618,6 +631,9 @@  int main(int argc, char **argv)
                 exit(EXIT_FAILURE);
             }
         }   break;
+        case QEMU_NBD_OPT_IMAGE_OPTS:
+            imageOpts = true;
+            break;
         }
     }
 
@@ -724,13 +740,29 @@  int main(int argc, char **argv)
     bdrv_init();
     atexit(bdrv_close_all);
 
-    if (fmt) {
-        options = qdict_new();
-        qdict_put(options, "driver", qstring_from_str(fmt));
+    srcpath = argv[optind];
+    if (imageOpts) {
+        QemuOpts *opts;
+        if (fmt) {
+            error_report("--image-opts and -f are mutually exclusive");
+            exit(EXIT_FAILURE);
+        }
+        opts = qemu_opts_parse_noisily(&file_opts, srcpath, true);
+        if (!opts) {
+            qemu_opts_reset(&file_opts);
+            exit(EXIT_FAILURE);
+        }
+        options = qemu_opts_to_qdict(opts, NULL);
+        qemu_opts_reset(&file_opts);
+        blk = blk_new_open("hda", NULL, NULL, options, flags, &local_err);
+    } else {
+        if (fmt) {
+            options = qdict_new();
+            qdict_put(options, "driver", qstring_from_str(fmt));
+        }
+        blk = blk_new_open("hda", srcpath, NULL, options, flags, &local_err);
     }
 
-    srcpath = argv[optind];
-    blk = blk_new_open("hda", srcpath, NULL, options, flags, &local_err);
     if (!blk) {
         error_reportf_err(local_err, "Failed to blk_new_open '%s': ",
                           argv[optind]);