74 lines
3.4 KiB
ReStructuredText
74 lines
3.4 KiB
ReStructuredText
=====================================
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``posix_spawn`` posix_spawn Unit Test
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=====================================
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This is a simple test of the ``posix_spawn()`` API. The example derives from
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``examples/elf``. As a result, these tests are built using the relocatable ELF
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format installed in a ROMFS file system. At run time, the test program in the
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ROMFS file system is spawned using ``posix_spawn()``.
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Requires:
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- ``CONFIG_BINFMT_DISABLE=n`` – Don't disable the binary loader.
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- ``CONFIG_ELF=y`` – Enable ELF binary loader.
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- ``CONFIG_LIBC_EXECFUNCS=y`` – Enable support for posix_spawn.
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- ``CONFIG_EXECFUNCS_SYMTAB_ARRAY="g_spawn_exports"`` – The name of the symbol
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table created by the test.
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- ``CONFIG_EXECFUNCS_NSYMBOLS_VAR="g_spawn_nexports"`` – Name of variable holding
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the number of symbols.
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- ``CONFIG_POSIX_SPAWN_STACKSIZE=768`` – This default setting.
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Test-specific configuration options:
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- ``CONFIG_EXAMPLES_POSIXSPAWN_DEVMINOR`` – The minor device number of the ROMFS
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block. driver. For example, the ``N`` in ``/dev/ramN``. Used for registering the
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RAM block driver that will hold the ROMFS file system containing the ELF
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executables to be tested. Default: ``0``.
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- ``CONFIG_EXAMPLES_POSIXSPAWN_DEVPATH`` – The path to the ROMFS block driver
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device. This must match ``EXAMPLES_POSIXSPAWN_DEVMINOR``. Used for registering
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the RAM block driver that will hold the ROMFS file system containing the ELF
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executables to be tested. Default: ``/dev/ram0``.
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**Notes**:
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1. ``CFLAGS`` should be provided in ``CELFFLAGS``. RAM and FLASH memory regions may
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require long allcs. For ARM, this might be::
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CELFFLAGS = $(CFLAGS) -mlong-calls
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Similarly for C++ flags which must be provided in ``CXXELFFLAGS``.
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2. Your top-level ``nuttx/Make.defs`` file must also include an appropriate
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definition, ``LDELFFLAGS``, to generate a relocatable ELF object. With GNU LD,
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this should include ``-r`` and ``-e main`` (or ``_main`` on some platforms).::
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LDELFFLAGS = -r -e main
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If you use GCC to link, you make also need to include ``-nostdlib``.
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3. This example also requires ``genromfs``. ``genromfs`` can be build as part of the
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nuttx toolchain. Or can built from the ``genromfs`` sources that can be found
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in the NuttX tools repository (``genromfs-0.5.2.tar.gz``). In any event, the
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``PATH`` variable must include the path to the ``genromfs`` executable.
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4. ELF size: The ELF files in this example are, be default, quite large because
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they include a lot of build garbage. You can greatly reduce the size of the
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ELF binaries are using the ``objcopy --strip-unneeded`` command to remove
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un-necessary information from the ELF files.
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5. Simulator. You cannot use this example with the NuttX simulator on Cygwin.
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That is because the Cygwin GCC does not generate ELF file but rather some
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Windows-native binary format.
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If you really want to do this, you can create a NuttX x86 buildroot toolchain
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and use that be build the ELF executables for the ROMFS file system.
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6. Linker scripts. You might also want to use a linker scripts to combine
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sections better. An example linker script is at
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``nuttx/binfmt/libelf/gnu-elf.ld``. That example might have to be tuned for
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your particular linker output to position additional sections correctly. The
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GNU LD ``LDELFFLAGS`` then might be::
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LDELFFLAGS = -r -e main -T$(TOPDIR)/binfmt/libelf/gnu-elf.ld
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