[libvirt] [PATCH] qemu driver: fix version parsing fix

[Jim Meyering]

Chris Wright wrote:
> * Eric Blake (eblake at redhat.com) wrote:
>> On 05/19/2010 04:37 PM, Chris Wright wrote:
>> > Looks like some cut'n paste error to me.
>>
>> While we're at it, there have been some complaints, at least on IRC,
>> that some recent qemu builds changed -help output to start with "QEMU
>> emulator version" instead of "QEMU PC emulator version", which fails to
>> match QEMU_VERSION_STR.  Is that something we should be worrying about,
>> while we're touching this function?
>
> That's what had me looking at it ;)
>
> [chrisw at x200 qemu-kvm]$ ./x86_64-softmmu/qemu-system-x86_64 -help | head -1
> QEMU emulator version 0.12.50 (qemu-kvm-devel), Copyright (c) 2003-2008 Fabrice Bellard
>
> [chrisw at x200 qemu-kvm]$ qemu-kvm -help | head -1
> QEMU PC emulator version 0.11.0 (qemu-kvm-0.11.0), Copyright (c) 2003-2008 Fabrice Bellard
>
> This keys off of only "emulator version", so should not have the
> same parsing issue.
>
> Signed-off-by: Chris Wright <chrisw at redhat.com>
> ---
>  src/qemu/qemu_conf.c |    9 ++++++---
>  1 files changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
> index 5fa8c0a..359c311 100644
> --- a/src/qemu/qemu_conf.c
> +++ b/src/qemu/qemu_conf.c
> @@ -1247,6 +1247,8 @@ static unsigned long long qemudComputeCmdFlags(const char *help,
>  /* We parse the output of 'qemu -help' to get the QEMU
>   * version number. The first bit is easy, just parse
>   * 'QEMU PC emulator version x.y.z'.
> + * or
> + * 'QEMU emulator version x.y.z'.
>   *
>   * With qemu-kvm, however, that is followed by a string
>   * in parenthesis as follows:
> @@ -1259,7 +1261,7 @@ static unsigned long long qemudComputeCmdFlags(const char *help,
>   * and later, we just need the QEMU version number and
>   * whether it is KVM QEMU or mainline QEMU.
>   */
> -#define QEMU_VERSION_STR    "QEMU PC emulator version"
> +#define QEMU_VERSION_STR    "emulator version"
>  #define QEMU_KVM_VER_PREFIX "(qemu-kvm-"
>  #define KVM_VER_PREFIX      "(kvm-"
>
> @@ -1277,9 +1279,10 @@ int qemudParseHelpStr(const char *qemu,
>
>      *flags = *version = *is_kvm = *kvm_version = 0;
>
> -    if (!STRPREFIX(p, QEMU_VERSION_STR))
> +    p = strstr(p, QEMU_VERSION_STR);
> +    if (!p)
>          goto fail;
>      p += strlen(QEMU_VERSION_STR);

Hi Chris,

That patch looks fine, and is nicely minimal.
However, it does relax the test significantly.
Rather than requiring that QEMU_VERSION_STR be a prefix,
it would allow it to appear anywhere within the -help output.

While I really doubt it'd ever make a difference,
it's easy to retain the stricter test, so I wrote this.
Either way is fine with me.

diff --git a/src/qemu/qemu_conf.c b/src/qemu/qemu_conf.c
index 5c14eb8..f43c6e2 100644
--- a/src/qemu/qemu_conf.c
+++ b/src/qemu/qemu_conf.c
@@ -1259,7 +1259,8 @@ static unsigned long long qemudComputeCmdFlags(const char *help,
  * and later, we just need the QEMU version number and
  * whether it is KVM QEMU or mainline QEMU.
  */
-#define QEMU_VERSION_STR    "QEMU PC emulator version"
+#define QEMU_VERSION_STR_1  "QEMU PC emulator version"
+#define QEMU_VERSION_STR_2  "QEMU emulator version"
 #define QEMU_KVM_VER_PREFIX "(qemu-kvm-"
 #define KVM_VER_PREFIX      "(kvm-"

@@ -1277,11 +1278,13 @@ int qemudParseHelpStr(const char *qemu,

     *flags = *version = *is_kvm = *kvm_version = 0;

-    if (!STRPREFIX(p, QEMU_VERSION_STR))
+    if (STRPREFIX(p, QEMU_VERSION_STR_1))
+        p += strlen(QEMU_VERSION_STR_1);
+    else if (STRPREFIX(p, QEMU_VERSION_STR_2))
+        p += strlen(QEMU_VERSION_STR_2);
+    else
         goto fail;

-    p += strlen(QEMU_VERSION_STR);
-
     SKIP_BLANKS(p);

     major = virParseNumber(&p);