[Qemu-devel] [PATCH v2] vl.c: Replace -virtfs string manipulation with QemuOpts

[Qemu-devel] [PATCH v2] vl.c: Replace -virtfs string manipulation with QemuOpts

[Stefan Hajnoczi]

The -virtfs option creates an fsdev representing the pass-through file
system and a guest-visible virtio-9p-pci device that can access this
file system.  This patch replaces the string manipulation used to build
and reparse option lists with direct QemuOpts calls.  Removing the
string manipulation code makes it easier to maintain and less error
prone.

An error message is also updated to use "mount_tag" instead of
"mnt_tag".

Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
---
v2:
 * Updated error message according to JV's suggestion

 vl.c |   56 +++++++++++++++++++-------------------------------------
 1 files changed, 19 insertions(+), 37 deletions(-)

diff --git a/vl.c b/vl.c
index b1a94aa..cf16e19 100644
--- a/vl.c
+++ b/vl.c
@@ -2411,9 +2411,8 @@ int main(int argc, char **argv, char **envp)
                 }
                 break;
             case QEMU_OPTION_virtfs: {
-                char *arg_fsdev = NULL;
-                char *arg_9p = NULL;
-                int len = 0;
+                QemuOpts *fsdev;
+                QemuOpts *device;
 
                 olist = qemu_find_opts("virtfs");
                 if (!olist) {
@@ -2432,45 +2431,28 @@ int main(int argc, char **argv, char **envp)
                         qemu_opt_get(opts, "security_model") == NULL) {
                     fprintf(stderr, "Usage: -virtfs fstype,path=/share_path/,"
                             "security_model=[mapped|passthrough|none],"
-                            "mnt_tag=tag.\n");
+                            "mount_tag=tag.\n");
                     exit(1);
                 }
 
-                len = strlen(",id=,path=,security_model=");
-                len += strlen(qemu_opt_get(opts, "fstype"));
-                len += strlen(qemu_opt_get(opts, "mount_tag"));
-                len += strlen(qemu_opt_get(opts, "path"));
-                len += strlen(qemu_opt_get(opts, "security_model"));
-                arg_fsdev = qemu_malloc((len + 1) * sizeof(*arg_fsdev));
-
-                snprintf(arg_fsdev, (len + 1) * sizeof(*arg_fsdev),
-                         "%s,id=%s,path=%s,security_model=%s",
-                         qemu_opt_get(opts, "fstype"),
-                         qemu_opt_get(opts, "mount_tag"),
-                         qemu_opt_get(opts, "path"),
-                         qemu_opt_get(opts, "security_model"));
-
-                len = strlen("virtio-9p-pci,fsdev=,mount_tag=");
-                len += 2*strlen(qemu_opt_get(opts, "mount_tag"));
-                arg_9p = qemu_malloc((len + 1) * sizeof(*arg_9p));
-
-                snprintf(arg_9p, (len + 1) * sizeof(*arg_9p),
-                         "virtio-9p-pci,fsdev=%s,mount_tag=%s",
-                         qemu_opt_get(opts, "mount_tag"),
-                         qemu_opt_get(opts, "mount_tag"));
-
-                if (!qemu_opts_parse(qemu_find_opts("fsdev"), arg_fsdev, 1)) {
-                    fprintf(stderr, "parse error [fsdev]: %s\n", optarg);
+                fsdev = qemu_opts_create(qemu_find_opts("fsdev"),
+                                         qemu_opt_get(opts, "mount_tag"), 1);
+                if (!fsdev) {
+                    fprintf(stderr, "duplicate fsdev id: %s\n",
+                            qemu_opt_get(opts, "mount_tag"));
                     exit(1);
                 }
-
-                if (!qemu_opts_parse(qemu_find_opts("device"), arg_9p, 1)) {
-                    fprintf(stderr, "parse error [device]: %s\n", optarg);
-                    exit(1);
-                }
-
-                qemu_free(arg_fsdev);
-                qemu_free(arg_9p);
+                qemu_opt_set(fsdev, "fstype", qemu_opt_get(opts, "fstype"));
+                qemu_opt_set(fsdev, "path", qemu_opt_get(opts, "path"));
+                qemu_opt_set(fsdev, "security_model",
+                             qemu_opt_get(opts, "security_model"));
+
+                device = qemu_opts_create(qemu_find_opts("device"), NULL, 0);
+                qemu_opt_set(device, "driver", "virtio-9p-pci");
+                qemu_opt_set(device, "fsdev",
+                             qemu_opt_get(opts, "mount_tag"));
+                qemu_opt_set(device, "mount_tag",
+                             qemu_opt_get(opts, "mount_tag"));
                 break;
             }
             case QEMU_OPTION_serial:
-- 
1.7.2.3

Re: [Qemu-devel] [PATCH v2] vl.c: Replace -virtfs string manipulation with QemuOpts

[Stefan Hajnoczi]

On Wed, Mar 16, 2011 at 8:31 AM, Stefan Hajnoczi
<stefanha@linux.vnet.ibm.com> wrote:
> The -virtfs option creates an fsdev representing the pass-through file
> system and a guest-visible virtio-9p-pci device that can access this
> file system.  This patch replaces the string manipulation used to build
> and reparse option lists with direct QemuOpts calls.  Removing the
> string manipulation code makes it easier to maintain and less error
> prone.
>
> An error message is also updated to use "mount_tag" instead of
> "mnt_tag".
>
> Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
> ---
> v2:
>  * Updated error message according to JV's suggestion
>
>  vl.c |   56 +++++++++++++++++++-------------------------------------
>  1 files changed, 19 insertions(+), 37 deletions(-)

Please help kill the string manipulation and review + merge this! :)

Stefan