2 Commits

Author	SHA1	Message	Date
Bryn M. Reeves	82a27a85b5	macros: fix default symbol export control ... Fix the version export macros to make it possible to export two different DM_* versions of a symbol: currently it is only possible for a DM_* symbol to override a symbol in Base. Attempting to export two symbols at different DM_* version levels (e.g. DM_1_02_104 and DM_1_02_106) leads to a linker error due to a duplicate symbol definition. This is because the DM_EXPORTED_SYMBOL macro makes each exported symbol the default (@@VERSION): __asm__(".symver " #func "_v" #ver ", " #func "@@DM_" #ver ) Fix the macro to use a single '@' for a symbols exported in multiple versions and rename the macros to DM_EXPORT_*: DM_EXPORT_SYMBOL(func,ver) DM_EXPORT_SYMBOL_BASE(func,ver) For functions that have multiple implementations these macros control symbol export and versioning. Function definitions that exist in only one version never need to use these macros. Backwards compatible implementations must include a version tag of the form "_v1_02_104" as a suffix to the function name and use the macro DM_EXPORT_SYMBOL to export the function and bind it to the specified version string. Since versioning is only available when compiling with GCC the entire compatibility version should be enclosed in '#if defined(__GNUC__)', for example: int dm_foo(int bar) { return bar; } #if defined(__GNUC__) // Backward compatible dm_foo() version 1.02.104 int dm_foo_v1_02_104(void); int dm_foo_v1_02_104(void) { return 0; } DM_EXPORT_SYMBOL(dm_foo,1_02_104) #endif A prototype for the compatibility version is required as these functions must not be declared static. The DM_EXPORT_SYMBOL_BASE macro is only used to export the base versions of library symbols prior to the introduction of symbol versioning: it must never be used for new symbols.	2015-08-24 20:03:21 +01:00
Zdenek Kabelac	797c18d543	libdm: new dm_task_get_info with internal_suspend ... Introduce new implmentation of dm_task_get_info() function with support for reading internal_suspend. . This time it is done in a 'versioned' way. We keep the old fashion dm_task_get_info(Base) to implement the old behavior of 1.02.95 libdm code. libdm version 1.02.96 introduced 'macro' wrapper dm_task_get_info_with_deferred_remove with new implementation of dm_task_get_info() - we cannot do anything else then to provide compatible version of this symbol. Now in version 1.02.97 we add new versioned implementation of dm_task_get_info(DM_1_02_97) symbol. This has the effect that i.e. rpm build will finaly resolve proper dependency on a new symbol - so it will be no longer possible, to build a new binary and use old library (rpm -q --provides will show libdevmapper.so.1.02(DM_1_02_97)(64bit)) Also the history is now tracked. If a new function is added (or reimplemented), it needs to be placed in proper file, so it could be exported with right versioning symbol. File .exported_symbols.Base should and any existing older DM should be treated as read-only after a release. Also - only libdm has been currently enhanced with versioned .Base file, as soon as other libs (liblvm, libdevmapper-event) needs changes they should also get their exported symbol files - meanwhile make.tmpl handles both cases.	2015-05-15 16:48:22 +02:00