[libvirt] [PATCH 09/11] tests: Use flat namespace on macOS

Roman Bolshakov posted 11 patches 6 years, 5 months ago
[libvirt] [PATCH 09/11] tests: Use flat namespace on macOS
Posted by Roman Bolshakov 6 years, 5 months ago
Test executables and mocks have assumption that any symbol can be
replaced with LD_PRELOAD. That's not a case for macOS unless flat
namespace is used, because every external symbol reference records the
library to be looked up. And the symbols cannot be replaced unless dyld
interposing is used.

Setting DYLD_FORCE_FLAT_NAMESPACE changes symbol lookup behaviour to be
similar to Linux dynamic linker. It's more lightweight solution than
explicitly decorating all mock symbols as interpositions and building
libvirt as interposable dynamic library.

This fixes vircryptotest and allows to proceed other tests that rely on
mocks a little bit further.

Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
---
 tests/testutils.h | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/tests/testutils.h b/tests/testutils.h
index 7660101991..b46bc86d84 100644
--- a/tests/testutils.h
+++ b/tests/testutils.h
@@ -119,9 +119,12 @@ int virTestMain(int argc,
 
 #ifdef __APPLE__
 # define PRELOAD_VAR "DYLD_INSERT_LIBRARIES"
+# define FORCE_FLAT_NAMESPACE \
+            setenv("DYLD_FORCE_FLAT_NAMESPACE", "1", 1);
 # define MOCK_EXT ".dylib"
 #else
 # define PRELOAD_VAR "LD_PRELOAD"
+# define FORCE_FLAT_NAMESPACE
 # define MOCK_EXT ".so"
 #endif
 
@@ -141,6 +144,7 @@ int virTestMain(int argc,
                 return EXIT_FAILURE; \
             } \
             setenv(PRELOAD_VAR, newenv, 1); \
+            FORCE_FLAT_NAMESPACE \
             execv(argv[0], argv); \
         } \
     } while (0)
-- 
2.22.0

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Re: [libvirt] [PATCH 09/11] tests: Use flat namespace on macOS
Posted by Daniel P. Berrangé 6 years, 5 months ago
On Wed, Aug 21, 2019 at 07:13:21PM +0300, Roman Bolshakov wrote:
> Test executables and mocks have assumption that any symbol can be
> replaced with LD_PRELOAD. That's not a case for macOS unless flat
> namespace is used, because every external symbol reference records the
> library to be looked up. And the symbols cannot be replaced unless dyld
> interposing is used.
> 
> Setting DYLD_FORCE_FLAT_NAMESPACE changes symbol lookup behaviour to be
> similar to Linux dynamic linker. It's more lightweight solution than
> explicitly decorating all mock symbols as interpositions and building
> libvirt as interposable dynamic library.
> 
> This fixes vircryptotest and allows to proceed other tests that rely on
> mocks a little bit further.
> 
> Signed-off-by: Roman Bolshakov <r.bolshakov@yadro.com>
> ---
>  tests/testutils.h | 4 ++++
>  1 file changed, 4 insertions(+)
> 
> diff --git a/tests/testutils.h b/tests/testutils.h
> index 7660101991..b46bc86d84 100644
> --- a/tests/testutils.h
> +++ b/tests/testutils.h
> @@ -119,9 +119,12 @@ int virTestMain(int argc,
>  
>  #ifdef __APPLE__
>  # define PRELOAD_VAR "DYLD_INSERT_LIBRARIES"
> +# define FORCE_FLAT_NAMESPACE \
> +            setenv("DYLD_FORCE_FLAT_NAMESPACE", "1", 1);

Remove the ';'

>  # define MOCK_EXT ".dylib"
>  #else
>  # define PRELOAD_VAR "LD_PRELOAD"
> +# define FORCE_FLAT_NAMESPACE

Make that  'do {} while (0)'

>  # define MOCK_EXT ".so"
>  #endif
>  
> @@ -141,6 +144,7 @@ int virTestMain(int argc,
>                  return EXIT_FAILURE; \
>              } \
>              setenv(PRELOAD_VAR, newenv, 1); \
> +            FORCE_FLAT_NAMESPACE \

so that here you can have a trailing ';'

>              execv(argv[0], argv); \
>          } \
>      } while (0)

Regards,
Daniel
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