Linker and Libraries Guide Appendix D Linker and Libraries Updates and New Features

This appendix provides an overview of the updates and new features that have been added to releases of the Solaris OS.

Solaris 10 5/08 Release

• Global auditing can now be enabled by recording an auditor within an application together with the link-editor -z globalauditoption. See Recording Global Auditors.

• Additional link-editor support interfaces, ld_open() and ld_open64() have been added. See Support Interface Functions.

Solaris 10 8/07 Release

• Greater flexibility in executing an alternative link-editor is provided with the link-editor -z altexec64 option, and the LD_ALTEXECenvironment variable. See The 32–bit link-editor and 64–bit link-editor.

• Symbol definitions that are generated using mapfiles can now be associated to ELF sections. See Defining Additional Symbols with a mapfile.

• The link-editors now provide for the creation of static TLS within shared objects. In addition, a backup TLS reservation is established to provide for limited use of static TLS within post-startup shared objects. See Program Startup.

Solaris 10 1/06 Release

• Support for the x64 medium code model is provided. See Table 7–4, Table 7–8, and Table 7–10.

• The command line arguments, environment variables, and auxiliary vector array of the process, can be obtained using the dlinfo(3C) flagRTLD_DI_ARGSINFO.

• Greater flexibility in prohibiting direct binding from external references is provided with the link-editor -B nodirect option. SeeDirect Bindings.

Solaris 10 Release

• x64 is now supported. See Table 7–5, Special Sections, x64: Relocation Types, x64: Thread-Local Variable Access, and x64: Thread-Local Storage Relocation Types.

• A restructuring of the filesystem has moved many components from under /usr/lib to /lib. Both the link-editor and runtime linkers default search paths have been changed accordingly. See Directories Searched by the Link-Editor, Directories Searched by the Runtime Linker, and Security.

• System archive libraries are no longer provided. Therefore, the creation of a statically linked executable is no longer possible. See Static Executables.

• Greater flexibility for defining alternative dependencies is provided with the -A option of crle(1).

• The link-editors now process environment variables specified without a value. See Environment Variables.

• Path names used with dlopen(3C), and as explicit dependency definitions, can now use any reserved tokens. See Appendix C, Establishing Dependencies with Dynamic String Tokens. The evaluation of path names that use reserved tokens is provided with the new utility moe(1).

• An optimal means of testing for the existence of an interface is provide with dlsym(3C) and the new handle RTLD_PROBE. SeeProviding an Alternative to dlopen().

Solaris 9 9/04 Release

• Greater flexibility in defining the hardware and software requirements of ELF objects is provided with the link-editors. See Hardware and Software Capabilities Section.

• The runtime link auditing interface la_objfilter() has been added. See Audit Interface Functions.

• Shared object filtering has been extended to provide filtering on a per-symbol basis. See Shared Objects as Filters.

Solaris 9 4/04 Release

• The new section types SHT_SUNW_ANNOTATE, SHT_SUNW_DEBUGSTR, SHT_SUNW_DEBUG, and SHT_SPARC_GOTDATA are supported. See Table 7–5.

• The analysis of runtime interfaces is simplified with the new utility lari(1).

• Greater control of direct bindings is provided with the link-editor options -z direct and -z nodirect, together with theDIRECT and NODIRECT mapfile directives. See Defining Additional Symbols with a mapfile, and Direct Bindings.

Solaris 9 12/03 Release

• Performance improvements within ld(1) can significantly reduce the link-edit time of very large applications.

Solaris 9 8/03 Release

• dlsym(3C) symbol processing can be reduced using a dlopen(3C) handle that is created with the RTLD_FIRST flag. See Obtaining New Symbols.

• The signal used by the runtime linker to terminate an erroneous process can be managed using the dlinfo(3C) flagsRTLD_DI_GETSIGNAL, and RTLD_DI_SETSIGNAL.

Solaris 9 12/02 Release

• The link-editor provides string table compression, that can result in reduced .dynstr and .strtab sections. This default processing can be disabled using the link-editor's -z nocompstrtab option. See String Table Compression.

• The -z ignore option has been extended to eliminate unreferenced sections during a link-edit. See Remove Unused Material.

• Unreferenced dependencies can be determined using ldd(1). See the -U option.

• The link-editors support extended ELF sections. See ELF Header, Table 7–5, Sections, Table 7–10 and Symbol Table Section.

• Greater flexibility in defining a symbols visibility is provided with the protected mapfile directive. See Defining Additional Symbols with a mapfile.

Solaris 9 Release

• Thread-Local Storage (TLS) support is provided. See Chapter 8, Thread-Local Storage.

• The -z rescan option provides greater flexibility in specifying archive libraries to a link-edit. See Position of an Archive on the Command Line.

• The -z ld32 and -z ld64 options provide greater flexibility in using the link-editor support interfaces. See 32–Bit Environments and 64–Bit Environments.

• Additional link-editor support interfaces, ld_input_done(), ld_input_section(), ld_input_section64() andld_version() have been added. See Support Interface Functions.

• Environment variables interpreted by the runtime linker can now be established for multiple processes by specifying these variables within a configuration file. See the -e and -E options of crle(1).

• Support for more than 32,768 procedure linkage table entries within 64–bit SPARC objects has been added. See 64-bit SPARC: Procedure Linkage Table.

• An mdb(1) debugger module enables you to inspect runtime linker data structures as part of process debugging. See Debugger Module.

• The bss segment declaration directive makes the creation of a bss segment easier. See Segment Declarations.

Solaris 8 07/01 Release

• Unused dependencies can be determined using ldd(1). See the -u option.

• Various ELF ABI extensions have been added. See Initialization and Termination Sections, Initialization and Termination Routines,Table 7–3, Table 7–8, Table 7–9, Group Section, Table 7–10, Table 7–20, Table 7–32, Table 7–33, and Program Loading (Processor-Specific).

• Greater flexibility in the use of link-editor environment variables has been provided with the addition of _32 and _64 variants. SeeEnvironment Variables.

Solaris 8 01/01 Release

• The symbolic information that is made available from dladdr(3C) has been enhanced with the introduction of dladdr1().

• The $ORIGIN of a dynamic object can be obtained from dlinfo(3C).

• The maintenance of runtime configuration files that are created with crle(1) has been simplified. Inspection of a configuration file displays the command line options used to create the file. An update capability is provided with the -u option.

• The runtime linker and its debugger interface have been extended to detect procedure linkage table entry resolution. This update is identified by a new version number. See rd_init() under Agent Manipulation Interfaces. This update extends therd_plt_info_t structure. See rd_plt_resolution() under Procedure Linkage Table Skipping.

• An application's stack can be defined non-executable by using the new mapfile segment descriptor STACK. See Segment Declarations.

Solaris 8 10/00 Release

• The environment variable LD_BREADTH is ignored by the runtime linker. See Initialization and Termination Routines.

• The runtime linker and its debugger interface have been extended for better runtime and core file analysis. This update is identified by a new version number. See rd_init() under Agent Manipulation Interfaces. This update extends the rd_loadobj_t structure. SeeScanning Loadable Objects.

• You can now validate displacement relocated data in regard to its use, or possible use, with copy relocations. See Displacement Relocations.

• 64–bit filters can be built solely from a mapfile by using the link-editor's -64 option. See Generating Standard Filters.

• The search paths used to locate the dependencies of dynamic objects can be inspected using dlinfo(3C).

• dlsym(3C) and dlinfo(3C) lookup semantics have been expanded with a new handle RTLD_SELF.

• The runtime symbol lookup mechanism used to relocate dynamic objects can be significantly reduced by establishing direct binding information within each dynamic object. See Direct Bindings.

Solaris 8 Release

• The secure directory from which files can be preloaded is now /usr/lib/secure for 32–bit objects, and /usr/lib/secure/64for 64–bit objects. See Security.

• Greater flexibility in modifying the runtime linker's search paths can be achieved with the link-editor's -z nodefaultlib option, and runtime configuration files created by the new utility crle(1). See Directories Searched by the Runtime Linker and Configuring the Default Search Paths.

• The new EXTERN mapfile directive enables you to use -z defs with externally defined symbols. See Defining Additional Symbols with a mapfile.

• The new $ISALIST, $OSNAME, and $OSREL dynamic string tokens provide greater flexibility in establishing instruction set specific, and system specific dependencies. See Dynamic String Tokens.

• The link-editor options -p and -P provide additional means of invoking runtime link auditing libraries. See Recording Local Auditors. The runtime link auditing interfaces la_activity() and la_objsearch() have been added. See Audit Interface Functions.

• A new dynamic section tag, DT_CHECKSUM, enables you to coordinate ELF files with core images. See Table 7–32.