nuttx/libs
Neale Ferguson fec789047a Add support for the loading of ET_DYN objects
* libs/libc/machine/arm/armv7-m/arch_elf.c
      - Fix cast of error message parameters

    * build-globals.sh
      - Build the modlib_globals.S file used to resolve symbols when dynamically loading

    * libs/libc/modlib/Make.defs
      - Build modlib_globals.S for all targets

    * libs/libc/modlib/modlib_load.c
      - Calculate sizes and text/data addresses based on program headers rather than section headers
      - Handle objects with no program headers

    * libs/libc/modlib/modlib_bind.c
      - Call modlib_readsym with pointer to symbol table
      - Add modlib_relocatedyn to manage relocation of symbols with shared object (ET_DYN)
      - Differentiate between ET_REL and ET_DYN objects
      - Use arch independent symbol ELF_R_SYM
      - Cast sizes to avoid warnings

    * libs/libc/modlib/modlib_load.c
      - Cast sizes to avoid warnings

    * include/elf.h
      - Add definitions that may be found in shared objects

    * include/nuttx/lib/modlib.h
      - Add parameter to modlib_readsym prototype
      - Add prototypes for:
        - modlib_insertsymtab
        - modlib_findglobal
      - Define Elf_Dyn and Elf_Off according to the elf architecture
      - Add fields to mod_loadifno_s:
        - Program headers
        - Exported symbols
        - Data section address
        - Padding requirement
        - Section index for dynamic symbol table
        - Number of symbols exported
      - Add prottotype for modlib_freesymtab

    * libs/libc/dlfcn/lib_dlclose.c
      - Free the symbol table when the dll is closed

    * libs/libc/dlfcn/lib_dlopen.c
      - Add dump of program headers to debug routine
      - Differentiate between ET_REL and ET_DYN objects

    * libs/libc/machine/arm/armv7-m/arch_elf.c
      - Add handling of R_ARM_RELATIVE and R_ARM_JUMP slot relocation types

    * libs/libc/modlib/modlib_loadshdrs.c
      - Rename modlib_loadshdrs.c to modlib_loadhdrs.c
      - Rename modlib_loadshdrs to modlib_loadhdrs
      - Add code to load program headers

    * libs/libc/modlib/modlib_symbols.c
      - Define entry point structure
      - Add offset parameter to modlib_symname() and use to find symbol names
      - Add symtab section header parameter to modlib_readsym()
      - Add offset parameter to modlib_symvalue() to locate symbol names
      - Add modlib_insertsyntab() to create a symbol table for exporting and resolution
      - Add findEP() to resolve a symbol in the modlib_global table
      - Add modlib_findglobal() to find symbol in the modlib_global table
      - Add modlib_freesymtab() to free the symbol table

    * libs/libc/modlib/modlib_uninit.c
      - Free header and sections from a module_loadinfo_s control block

    * libs/libc/modlib/modlib_verify.c
      - Handle ET_DYN shared objects

    * libs/libc/modlib/modlib_globals.S
      - Multi-target global table
      - Define library APIs that may be resolved when loading a shared object
2023-07-06 09:13:38 -03:00
..
libc Add support for the loading of ET_DYN objects 2023-07-06 09:13:38 -03:00
libdsp libdsp: Add average filter 2023-06-12 08:39:38 +02:00
libm Indent the define statement by two spaces 2023-05-21 09:52:08 -03:00
libnx Indent the define statement by two spaces 2023-05-21 09:52:08 -03:00
libxx libs/libxx: remove redundant code 2023-05-03 19:54:19 +08:00
README.txt

README
======

This directory holds NuttX libraries.  Libraries in NuttX are very special
creatures.  They have these properties:

1. They can be shared by both application logic and logic within the OS when
   using the FLAT build.

2. But in PROTECTED and KERNEL modes, they must be built differently:  The
   copies used by applications and the OS cannot be the same.  Rather,
   separate versions of libraries must be built for the kernel and for
   applications.

3. When used by the OS, some special care must be taken to assure that the
   OS logic does not disrupt the user's errno value and that the OS does
   not create inappropriate cancellation points.

   For example, sem_wait() is both a cancellation point and modifies the
   errno value.  So within the FLAT build and without kernel version for
   the PROTECTED and KERNEL builds, the special internal OS interface
   nxsem_wait() must be used.  Within libraries, the macro _SEM_WAIT()
   (as defined in include/nuttx/semaphore.h) is used instead.  The
   definition of this macro accounts for the different usage environments.

NOTE:  The libraries under libs/ build differently from other NuttX
components:  There are no build-related files in the libs/ directory; it
is simply a container for other well-known, individual library directories.
The upper level Makefile logic is aware of the libraries within the libs/
container.

The only real function of the libs/ directory is to prevent the top-level
directory from becoming cluttered with individual libraries.