[Qemu-devel] QEmu: support disk filenames with comma

[Qemu-devel] QEmu: support disk filenames with comma

[Crístian Viana]

Hi!

This patch fixes RHBZ #801036 adding support to filenames with comma using QEmu. As this is my first patch to libvirt, I'm not completely sure if I should have also changed other parts of the code, or if I have used the wrong memory allocation functions/macros, or if I shouldn't have created a separate commit to add my name to the AUTHORS file... :-)

I also need to make it clear that this patch only fixes the problem in the "libvirt data -> QEmu args" way (e.g., when QEmu reads an XML file to start QEmu, or when using virsh domxml-to-native). The other way, "QEmu args -> libvirt data" is *not* implemented (e.g., virsh domxml-from-native). I would like to know if I'm going in the right way so I can continue working on this patch, and if that half of the feature is also needed.

Any feedback is welcome, thanks!

Best regards,
Crístian.

[Qemu-devel] [PATCH 1/2] QEmu: support disk filenames with comma

[Crístian Viana]

If there is a disk file with a comma in the name, QEmu expects a double
comma instead of a single one (e.g., the file "virtual,disk.img" needs
to be specified as "virtual,,disk.img" in QEmu's command line). This
patch fixes libvirt to work with that feature. Fix RHBZ #801036.

diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index de2d4a1..685a278 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -1628,6 +1628,48 @@ qemuSafeSerialParamValue(const char *value)
     return 0;
 }
 
+static const char *
+qemuEscapeCommas(const char *name)
+{
+    const char *name_ptr = name;
+    char *escaped_name, *escaped_name_ptr;
+    size_t escaped_name_max_size = (strlen(name) * 2) + 1;
+
+    /* If there is no comma in the string, return a copy of the original one. */
+    if (!strchr(name, ',')) {
+        if (!(escaped_name = strdup(name))) {
+            virReportOOMError();
+            return NULL;
+        }
+        return escaped_name;
+    }
+
+    /* In the worst case the string will have a sequence of only commas,
+     * which will require double the space for the escaped string. */
+    if (VIR_ALLOC_N(escaped_name, escaped_name_max_size) < 0) {
+        virReportOOMError();
+        return NULL;
+    }
+
+    /* Insert a comma after each comma in the string. */
+    escaped_name_ptr = escaped_name;
+    while (*name_ptr != '\0') {
+        if (*name_ptr == ',') {
+            *escaped_name_ptr++ = ',';
+        }
+
+        *escaped_name_ptr++ = *name_ptr++;
+    }
+
+    escaped_name_ptr = '\0';
+
+    /* Reduce the string memory size to its current length. */
+    VIR_SHRINK_N(escaped_name, escaped_name_max_size,
+            strlen(escaped_name) - strlen(name));
+
+    return escaped_name;
+}
+
 static int
 qemuBuildRBDString(virConnectPtr conn,
                    virDomainDiskDefPtr disk,
@@ -1638,7 +1680,7 @@ qemuBuildRBDString(virConnectPtr conn,
     char *secret = NULL;
     size_t secret_size;
 
-    virBufferAsprintf(opt, "rbd:%s", disk->src);
+    virBufferAsprintf(opt, "rbd:%s", qemuEscapeCommas(disk->src));
     if (disk->auth.username) {
         virBufferEscape(opt, ":", ":id=%s", disk->auth.username);
         /* look up secret */
@@ -1922,9 +1964,9 @@ qemuBuildDriveStr(virConnectPtr conn ATTRIBUTE_UNUSED,
                 goto error;
             }
             if (disk->device == VIR_DOMAIN_DISK_DEVICE_FLOPPY)
-                virBufferAsprintf(&opt, "file=fat:floppy:%s,", disk->src);
+                virBufferAsprintf(&opt, "file=fat:floppy:%s,", qemuEscapeCommas(disk->src));
             else
-                virBufferAsprintf(&opt, "file=fat:%s,", disk->src);
+                virBufferAsprintf(&opt, "file=fat:%s,", qemuEscapeCommas(disk->src));
         } else if (disk->type == VIR_DOMAIN_DISK_TYPE_NETWORK) {
             switch (disk->protocol) {
             case VIR_DOMAIN_DISK_PROTOCOL_NBD:
@@ -1944,16 +1986,16 @@ qemuBuildDriveStr(virConnectPtr conn ATTRIBUTE_UNUSED,
                 break;
             case VIR_DOMAIN_DISK_PROTOCOL_SHEEPDOG:
                 if (disk->nhosts == 0)
-                    virBufferAsprintf(&opt, "file=sheepdog:%s,", disk->src);
+                    virBufferAsprintf(&opt, "file=sheepdog:%s,", qemuEscapeCommas(disk->src));
                 else
                     /* only one host is supported now */
                     virBufferAsprintf(&opt, "file=sheepdog:%s:%s:%s,",
                                       disk->hosts->name, disk->hosts->port,
-                                      disk->src);
+                                      qemuEscapeCommas(disk->src));
                 break;
             }
         } else {
-            virBufferAsprintf(&opt, "file=%s,", disk->src);
+            virBufferAsprintf(&opt, "file=%s,", qemuEscapeCommas(disk->src));
         }
     }
     if (qemuCapsGet(qemuCaps, QEMU_CAPS_DEVICE))
@@ -2134,7 +2176,6 @@ error:
     return NULL;
 }
 
-
 char *
 qemuBuildDriveDevStr(virDomainDefPtr def,
                      virDomainDiskDefPtr disk,
-- 
1.7.8.5

[Qemu-devel] [PATCH 2/2] Add myself to the AUTHORS file

[Crístian Viana]

diff --git a/AUTHORS b/AUTHORS
index 954fd1a..b09bd62 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -224,6 +224,7 @@ Patches have also been contributed by:
   Peter Robinson       <pbrobinson@gmail.com>
   Benjamin Cama        <benoar@dolka.fr>
   Duncan Rance         <libvirt@dunquino.com>
+  Crístian Viana       <vianac@linux.vnet.ibm.com>
 
   [....send patches to get your name here....]
 
-- 
1.7.8.5

Re: [Qemu-devel] QEmu: support disk filenames with comma

[Eric Blake]

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On 03/09/2012 09:02 AM, Crístian Viana wrote:
> 
> Hi!
> 
> This patch fixes RHBZ #801036 adding support to filenames with comma using QEmu. As this is my first patch to libvirt,
...
> 
> Any feedback is welcome, thanks!

For starters, you mailed the qemu list.  This patch should be sent
instead to libvir-list@redhat.com, so that it will actually reach the
libvirt folks.

-- 
Eric Blake   eblake@redhat.com    +1-919-301-3266
Libvirt virtualization library http://libvirt.org


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Re: [Qemu-devel] QEmu: support disk filenames with comma

[Crístian Viana]

On 09-03-2012 14:27, Eric Blake wrote:
> For starters, you mailed the qemu list.  This patch should be sent
> instead to libvir-list@redhat.com, so that it will actually reach the
> libvirt folks.
> 

Oh, sorry, wrong list :-) I'll mail the right one then.

Thanks!

Re: [Qemu-devel] [PATCH 1/2] QEmu: support disk filenames with comma

[Anthony Liguori]

On 03/09/2012 10:02 AM, Crístian Viana wrote:
> If there is a disk file with a comma in the name, QEmu expects a double
> comma instead of a single one (e.g., the file "virtual,disk.img" needs
> to be specified as "virtual,,disk.img" in QEmu's command line). This
> patch fixes libvirt to work with that feature. Fix RHBZ #801036.

I think you meant to send this to libvir-devel.

Regards,

Anthony Liguori

>
> diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
> index de2d4a1..685a278 100644
> --- a/src/qemu/qemu_command.c
> +++ b/src/qemu/qemu_command.c
> @@ -1628,6 +1628,48 @@ qemuSafeSerialParamValue(const char *value)
>       return 0;
>   }
>
> +static const char *
> +qemuEscapeCommas(const char *name)
> +{
> +    const char *name_ptr = name;
> +    char *escaped_name, *escaped_name_ptr;
> +    size_t escaped_name_max_size = (strlen(name) * 2) + 1;
> +
> +    /* If there is no comma in the string, return a copy of the original one. */
> +    if (!strchr(name, ',')) {
> +        if (!(escaped_name = strdup(name))) {
> +            virReportOOMError();
> +            return NULL;
> +        }
> +        return escaped_name;
> +    }
> +
> +    /* In the worst case the string will have a sequence of only commas,
> +     * which will require double the space for the escaped string. */
> +    if (VIR_ALLOC_N(escaped_name, escaped_name_max_size)<  0) {
> +        virReportOOMError();
> +        return NULL;
> +    }
> +
> +    /* Insert a comma after each comma in the string. */
> +    escaped_name_ptr = escaped_name;
> +    while (*name_ptr != '\0') {
> +        if (*name_ptr == ',') {
> +            *escaped_name_ptr++ = ',';
> +        }
> +
> +        *escaped_name_ptr++ = *name_ptr++;
> +    }
> +
> +    escaped_name_ptr = '\0';
> +
> +    /* Reduce the string memory size to its current length. */
> +    VIR_SHRINK_N(escaped_name, escaped_name_max_size,
> +            strlen(escaped_name) - strlen(name));
> +
> +    return escaped_name;
> +}
> +
>   static int
>   qemuBuildRBDString(virConnectPtr conn,
>                      virDomainDiskDefPtr disk,
> @@ -1638,7 +1680,7 @@ qemuBuildRBDString(virConnectPtr conn,
>       char *secret = NULL;
>       size_t secret_size;
>
> -    virBufferAsprintf(opt, "rbd:%s", disk->src);
> +    virBufferAsprintf(opt, "rbd:%s", qemuEscapeCommas(disk->src));
>       if (disk->auth.username) {
>           virBufferEscape(opt, ":", ":id=%s", disk->auth.username);
>           /* look up secret */
> @@ -1922,9 +1964,9 @@ qemuBuildDriveStr(virConnectPtr conn ATTRIBUTE_UNUSED,
>                   goto error;
>               }
>               if (disk->device == VIR_DOMAIN_DISK_DEVICE_FLOPPY)
> -                virBufferAsprintf(&opt, "file=fat:floppy:%s,", disk->src);
> +                virBufferAsprintf(&opt, "file=fat:floppy:%s,", qemuEscapeCommas(disk->src));
>               else
> -                virBufferAsprintf(&opt, "file=fat:%s,", disk->src);
> +                virBufferAsprintf(&opt, "file=fat:%s,", qemuEscapeCommas(disk->src));
>           } else if (disk->type == VIR_DOMAIN_DISK_TYPE_NETWORK) {
>               switch (disk->protocol) {
>               case VIR_DOMAIN_DISK_PROTOCOL_NBD:
> @@ -1944,16 +1986,16 @@ qemuBuildDriveStr(virConnectPtr conn ATTRIBUTE_UNUSED,
>                   break;
>               case VIR_DOMAIN_DISK_PROTOCOL_SHEEPDOG:
>                   if (disk->nhosts == 0)
> -                    virBufferAsprintf(&opt, "file=sheepdog:%s,", disk->src);
> +                    virBufferAsprintf(&opt, "file=sheepdog:%s,", qemuEscapeCommas(disk->src));
>                   else
>                       /* only one host is supported now */
>                       virBufferAsprintf(&opt, "file=sheepdog:%s:%s:%s,",
>                                         disk->hosts->name, disk->hosts->port,
> -                                      disk->src);
> +                                      qemuEscapeCommas(disk->src));
>                   break;
>               }
>           } else {
> -            virBufferAsprintf(&opt, "file=%s,", disk->src);
> +            virBufferAsprintf(&opt, "file=%s,", qemuEscapeCommas(disk->src));
>           }
>       }
>       if (qemuCapsGet(qemuCaps, QEMU_CAPS_DEVICE))
> @@ -2134,7 +2176,6 @@ error:
>       return NULL;
>   }
>
> -
>   char *
>   qemuBuildDriveDevStr(virDomainDefPtr def,
>                        virDomainDiskDefPtr disk,