Appendix D

New Linker and Libraries Features and Updates

This appendix provides an overview of new features and updates that have been added to the Solaris operating environment and indicates the release to which they were added:

Solaris 9 Release

The -z rescan option provides reater 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 and 64-Bit Environments".
Additional link-editor support interfaces ld_input_done(), ld_input_section(), ld_input_section64() and ld_version() have been added. See "Support Interface Functions".
Environment variables interpreted by the runtime linker can now be established for multiple processes by specifying them 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 "SPARC: 64-bit Procedure Linkage Table".
An mdb(1) debugger module enables you to inspect runtime linker data structures a 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 7-4, Table 7-7, Table 7-14, Table 7-15, "Section Groups", Table 7-17, Table 7-21, Table 7-42, Table 7-43, 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. See "Environment Variables".

Solaris 8 01/01 Release

The symbolic information available from dladdr(3DL) has been enhanced with the introduction of dladdr1().
The $ORIGIN of a dynamic object can be obtained from dlinfo(3DL).
The maintenance of runtime configuration files 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 the rd_plt_info_t structure. See rd_plt_resolution() under "Procedure Linkage Table Skipping".
An application's stack can be defined non-executable 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. See "Scanning 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 using the link-editor's -64 option. See "Generating a Standard Filter".
The search paths used to locate the dependencies of dynamic objects can be inspected using dlinfo(3DL).
dlsym(3DL) and dlinfo(3DL) 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 "External Bindings" and "Direct Binding".

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/64 for 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".
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 7-42.

Solaris 7 Release

The 64-bit ELF object format is now supported. See "File Format" for details. Link-editor extensions and differences for 64-bit processing include the use of /usr/lib/64 (see "Directories Searched by the Link-Editor", "Directories Searched by the Runtime Linker", and "Naming Conventions"), the environment variable LD_LIBRARY_PATH_64 (see "Using an Environment Variable", and "Directories Searched by the Runtime Linker"), and the runtime linker /usr/lib/64/ld.so.1 (see Chapter 3, Runtime Linker).
You can build shared objects with optimized relocation sections using the link-editor's -z combreloc option. See "Combined Relocation Sections".
The new $ORIGIN dynamic string token provides greater flexibility in establishing dependencies within unbundled software. See "Dynamic String Tokens".
The loading of a shared object can now be deferred until the object is actually referenced by the running program. See "Lazy Loading of Dynamic Dependencies".
The new SHT_SUNW_COMDAT section type enables the elimination of multiply-defined symbols. See "Comdat Section".
The new SHT_SUNW_move section type enables partially initialized symbols. See "Move Section".
The runtime link auditing interfaces la_symbind64(), la_sparcv9_pltenter(), and la_pltexit64(), together with a new link-auditing flag LA_SYMB_ALTVALUE, have been added. See "Audit Interface Functions".


	Appendix D New Linker and Libraries Features and Updates This appendix provides an overview of new features and updates that have been added to the Solaris operating environment and indicates the release to which they were added: Solaris 9 Release The `-z rescan` option provides reater 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 and 64-Bit Environments". Additional link-editor support interfaces `ld_input_done()`, `ld_input_section()`, `ld_input_section64()` and `ld_version()` have been added. See "Support Interface Functions". Environment variables interpreted by the runtime linker can now be established for multiple processes by specifying them 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 "SPARC: 64-bit Procedure Linkage Table". An `mdb`(1) debugger module enables you to inspect runtime linker data structures a 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 7-4, Table 7-7, Table 7-14, Table 7-15, "Section Groups", Table 7-17, Table 7-21, Table 7-42, Table 7-43, 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. See "Environment Variables". Solaris 8 01/01 Release The symbolic information available from `dladdr`(3DL) has been enhanced with the introduction of `dladdr1()`. The `$ORIGIN` of a dynamic object can be obtained from `dlinfo`(3DL). The maintenance of runtime configuration files 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 the `rd_plt_info_t` structure. See `rd_plt_resolution()` under "Procedure Linkage Table Skipping". An application's stack can be defined non-executable 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. See "Scanning 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` using the link-editor's `-64` option. See "Generating a Standard Filter". The search paths used to locate the dependencies of dynamic objects can be inspected using `dlinfo`(3DL). `dlsym`(3DL) and `dlinfo`(3DL) 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 "External Bindings" and "Direct Binding". 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/64` for 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". 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 7-42. Solaris 7 Release The 64-bit ELF object format is now supported. See "File Format" for details. Link-editor extensions and differences for 64-bit processing include the use of `/usr/lib/64` (see "Directories Searched by the Link-Editor", "Directories Searched by the Runtime Linker", and "Naming Conventions"), the environment variable `LD_LIBRARY_PATH_64` (see "Using an Environment Variable", and "Directories Searched by the Runtime Linker"), and the runtime linker `/usr/lib/64/ld.so.1` (see Chapter 3, Runtime Linker). You can build shared objects with optimized relocation sections using the link-editor's `-z combreloc` option. See "Combined Relocation Sections". The new `$ORIGIN` dynamic string token provides greater flexibility in establishing dependencies within unbundled software. See "Dynamic String Tokens". The loading of a shared object can now be deferred until the object is actually referenced by the running program. See "Lazy Loading of Dynamic Dependencies". The new `SHT_SUNW_COMDAT` section type enables the elimination of multiply-defined symbols. See "Comdat Section". The new `SHT_SUNW_move` section type enables partially initialized symbols. See "Move Section". The runtime link auditing interfaces `la_symbind64()`, `la_sparcv9_pltenter()`, and `la_pltexit64()`, together with a new link-auditing flag `LA_SYMB_ALTVALUE`, have been added. See "Audit Interface Functions".