[RFC PATCH] os-posix: fix regression for install-less datadir location

Marc-André Lureau posted 1 patch 3 years, 8 months ago
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git fetch https://github.com/patchew-project/qemu tags/patchew/20200716141100.398296-1-marcandre.lureau@redhat.com
os-posix.c            | 15 ++++++++++++---
scripts/create_config |  2 +-
2 files changed, 13 insertions(+), 4 deletions(-)
[RFC PATCH] os-posix: fix regression for install-less datadir location
Posted by Marc-André Lureau 3 years, 8 months ago
os_find_datadir() used to check the ../share/qemu location (regardless
of CONFIG_QEMU_DATADIR). It turns out that people rely on that location
for running qemu in an arbitrary "install-less/portable" fashion. Change
the logic to return that directory as a last resort.

(this is an alternative to the patch "[PATCH 1/1] os_find_datadir: search
as in version 4.2" from Joe Slater)

Fixes: 6dd2dacedd83d12328 ("os-posix: simplify os_find_datadir")
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 os-posix.c            | 15 ++++++++++++---
 scripts/create_config |  2 +-
 2 files changed, 13 insertions(+), 4 deletions(-)

diff --git a/os-posix.c b/os-posix.c
index b674b20b1b1..bd0ed0c14d1 100644
--- a/os-posix.c
+++ b/os-posix.c
@@ -82,8 +82,13 @@ void os_setup_signal_handling(void)
 
 /*
  * Find a likely location for support files using the location of the binary.
- * When running from the build tree this will be "$bindir/../pc-bios".
- * Otherwise, this is CONFIG_QEMU_DATADIR.
+ *
+ * If running from the install location (CONFIG_BINDIR), this will be
+ * CONFIG_QEMU_DATADIR.
+ *
+ * Otherwise, fallback on "$execdir/../pc-bios" if it exists (the build tree
+ * location), else on "$execdir/../share/qemu" (for the install-less/"portable"
+ * version).
  */
 char *os_find_datadir(void)
 {
@@ -93,12 +98,16 @@ char *os_find_datadir(void)
     exec_dir = qemu_get_exec_dir();
     g_return_val_if_fail(exec_dir != NULL, NULL);
 
+    if (g_str_has_prefix(exec_dir, CONFIG_BINDIR)) {
+        return g_strdup(CONFIG_QEMU_DATADIR);
+    }
+
     dir = g_build_filename(exec_dir, "..", "pc-bios", NULL);
     if (g_file_test(dir, G_FILE_TEST_IS_DIR)) {
         return g_steal_pointer(&dir);
     }
 
-    return g_strdup(CONFIG_QEMU_DATADIR);
+    return g_build_filename(exec_dir, "..", "share", "qemu", NULL);
 }
 
 void os_set_proc_name(const char *s)
diff --git a/scripts/create_config b/scripts/create_config
index 6d8f08b39da..03f8cb1dc10 100755
--- a/scripts/create_config
+++ b/scripts/create_config
@@ -15,7 +15,7 @@ case $line in
     echo "#define QEMU_VERSION_MINOR $minor"
     echo "#define QEMU_VERSION_MICRO $micro"
     ;;
- qemu_*dir=* | qemu_*path=*) # qemu-specific directory configuration
+ bindir=* | qemu_*dir=* | qemu_*path=*) # qemu-specific directory configuration
     name=${line%=*}
     value=${line#*=}
     define_name=$(echo $name | LC_ALL=C tr '[a-z]' '[A-Z]')
-- 
2.27.0.221.ga08a83db2b


Re: [RFC PATCH] os-posix: fix regression for install-less datadir location
Posted by Marc-André Lureau 3 years, 8 months ago
Hi

On Thu, Jul 16, 2020 at 6:11 PM Marc-André Lureau <
marcandre.lureau@redhat.com> wrote:

> os_find_datadir() used to check the ../share/qemu location (regardless
> of CONFIG_QEMU_DATADIR). It turns out that people rely on that location
> for running qemu in an arbitrary "install-less/portable" fashion. Change
> the logic to return that directory as a last resort.
>
> (this is an alternative to the patch "[PATCH 1/1] os_find_datadir: search
> as in version 4.2" from Joe Slater)
>
> Fixes: 6dd2dacedd83d12328 ("os-posix: simplify os_find_datadir")
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> ---
>  os-posix.c            | 15 ++++++++++++---
>  scripts/create_config |  2 +-
>  2 files changed, 13 insertions(+), 4 deletions(-)
>
> diff --git a/os-posix.c b/os-posix.c
> index b674b20b1b1..bd0ed0c14d1 100644
> --- a/os-posix.c
> +++ b/os-posix.c
> @@ -82,8 +82,13 @@ void os_setup_signal_handling(void)
>
>  /*
>   * Find a likely location for support files using the location of the
> binary.
> - * When running from the build tree this will be "$bindir/../pc-bios".
> - * Otherwise, this is CONFIG_QEMU_DATADIR.
> + *
> + * If running from the install location (CONFIG_BINDIR), this will be
> + * CONFIG_QEMU_DATADIR.
> + *
> + * Otherwise, fallback on "$execdir/../pc-bios" if it exists (the build
> tree
> + * location), else on "$execdir/../share/qemu" (for the
> install-less/"portable"
> + * version).
>   */
>  char *os_find_datadir(void)
>  {
> @@ -93,12 +98,16 @@ char *os_find_datadir(void)
>      exec_dir = qemu_get_exec_dir();
>      g_return_val_if_fail(exec_dir != NULL, NULL);
>
> +    if (g_str_has_prefix(exec_dir, CONFIG_BINDIR)) {
>

I realize g_str_has_prefix() may not be good enough (it was meant to ignore
the / suffix..). I guess we can just go with the version from Joe instead.


+        return g_strdup(CONFIG_QEMU_DATADIR);
> +    }
> +
>      dir = g_build_filename(exec_dir, "..", "pc-bios", NULL);
>      if (g_file_test(dir, G_FILE_TEST_IS_DIR)) {
>          return g_steal_pointer(&dir);
>      }
>
> -    return g_strdup(CONFIG_QEMU_DATADIR);
> +    return g_build_filename(exec_dir, "..", "share", "qemu", NULL);
>  }
>
>  void os_set_proc_name(const char *s)
> diff --git a/scripts/create_config b/scripts/create_config
> index 6d8f08b39da..03f8cb1dc10 100755
> --- a/scripts/create_config
> +++ b/scripts/create_config
> @@ -15,7 +15,7 @@ case $line in
>      echo "#define QEMU_VERSION_MINOR $minor"
>      echo "#define QEMU_VERSION_MICRO $micro"
>      ;;
> - qemu_*dir=* | qemu_*path=*) # qemu-specific directory configuration
> + bindir=* | qemu_*dir=* | qemu_*path=*) # qemu-specific directory
> configuration
>      name=${line%=*}
>      value=${line#*=}
>      define_name=$(echo $name | LC_ALL=C tr '[a-z]' '[A-Z]')
> --
> 2.27.0.221.ga08a83db2b
>
>
>

-- 
Marc-André Lureau
Re: [RFC PATCH] os-posix: fix regression for install-less datadir location
Posted by Paolo Bonzini 3 years, 7 months ago
On 16/07/20 16:11, Marc-André Lureau wrote:
> os_find_datadir() used to check the ../share/qemu location (regardless
> of CONFIG_QEMU_DATADIR). It turns out that people rely on that location
> for running qemu in an arbitrary "install-less/portable" fashion. Change
> the logic to return that directory as a last resort.
> 
> (this is an alternative to the patch "[PATCH 1/1] os_find_datadir: search
> as in version 4.2" from Joe Slater)
> 
> Fixes: 6dd2dacedd83d12328 ("os-posix: simplify os_find_datadir")
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>

For 5.2 I plan to support fully relocatable installs, so I think this
will not be needed.

The idea is to write a function like

char *get_relocatable_path(const char *dir);

That takes CONFIG_QEMU_*DIR as the argument, turns it into a path
relative to bindir, and tacks it to the end of qemu_get_exec_dir().

So for example all references to CONFIG_QEMU_DATADIR would invoke
get_relocatable_path(CONFIG_QEMU_DATADIR), which would return something
like "/usr/bin/../share/qemu".

Paolo


Re: [RFC PATCH] os-posix: fix regression for install-less datadir location
Posted by Peter Maydell 3 years, 7 months ago
On Tue, 18 Aug 2020 at 10:11, Paolo Bonzini <pbonzini@redhat.com> wrote:
>
> On 16/07/20 16:11, Marc-André Lureau wrote:
> > os_find_datadir() used to check the ../share/qemu location (regardless
> > of CONFIG_QEMU_DATADIR). It turns out that people rely on that location
> > for running qemu in an arbitrary "install-less/portable" fashion. Change
> > the logic to return that directory as a last resort.
> >
> > (this is an alternative to the patch "[PATCH 1/1] os_find_datadir: search
> > as in version 4.2" from Joe Slater)
> >
> > Fixes: 6dd2dacedd83d12328 ("os-posix: simplify os_find_datadir")
> > Cc: Paolo Bonzini <pbonzini@redhat.com>
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
>
> For 5.2 I plan to support fully relocatable installs, so I think this
> will not be needed.
>
> The idea is to write a function like
>
> char *get_relocatable_path(const char *dir);
>
> That takes CONFIG_QEMU_*DIR as the argument, turns it into a path
> relative to bindir, and tacks it to the end of qemu_get_exec_dir().
>
> So for example all references to CONFIG_QEMU_DATADIR would invoke
> get_relocatable_path(CONFIG_QEMU_DATADIR), which would return something
> like "/usr/bin/../share/qemu".

Unless you have that series ready-to-roll, I think it would
be useful to just fix the regression (and cc qemu-stable on it
so it gets backported to 5.1.1) for the moment.

thanks
-- PMM

Re: [RFC PATCH] os-posix: fix regression for install-less datadir location
Posted by Paolo Bonzini 3 years, 7 months ago
On 18/08/20 15:10, Peter Maydell wrote:
>> So for example all references to CONFIG_QEMU_DATADIR would invoke
>> get_relocatable_path(CONFIG_QEMU_DATADIR), which would return something
>> like "/usr/bin/../share/qemu".
> Unless you have that series ready-to-roll, I think it would
> be useful to just fix the regression (and cc qemu-stable on it
> so it gets backported to 5.1.1) for the moment.

I have it ready but I agree it's not suitable for backporting (among
other things, I've never tested it on the non-meson build system).  I
can rebase it on top of this patch with no issue.

Paolo