[libcamera-devel,v4,1/2] libcamera: ipa_module: add IPA shared library module

1240 diff mbox series

Implement a class to wrap around an IPA module shared object.

For now, just load a struct IPAModuleInfo with symbol name
ipaModuleInfo from an IPA module .so shared object.

Also provide a public header file including the struct IPAModuleInfo,
structured such that both C and C++ IPA modules are supported.

Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
---
Changes in v4:
- added overloaded elfPointer to specify the size to check for in the
  case that it cannot be obtained from the type (eg. char[size])
- documentation formalization
- other cosmetic changes

Changes in v3:
- created public header file for IPAModuleInfo (and for handling C vs
  C++ IPA modules)
- made ELF loading/parsing functions static
- got rid of bitClass_
- other cosmetic changes

Changes in v2:
- renamed LibLoader class to IPAModule
- added documentation
- added logging
- check that bitness of the shared object is the same as libcamera
- moved symbol loading ("init") to the constructor, and added isValid()
- added elfPointer() to prevent segfaults when reading data from mmap
- moved struct IPAModuleInfo out of IPAModule
- rename getIPAModuleInfo() to IPAModuleInfo(), and make it return a
  const reference
- added munmap after the mmap

 include/libcamera/ipa/ipa_module_info.h |  31 +++
 include/libcamera/meson.build           |   1 +
 src/libcamera/include/ipa_module.h      |  35 +++
 src/libcamera/ipa_module.cpp            | 290 ++++++++++++++++++++++++
 src/libcamera/meson.build               |   2 +
 5 files changed, 359 insertions(+)
 create mode 100644 include/libcamera/ipa/ipa_module_info.h
 create mode 100644 src/libcamera/include/ipa_module.h
 create mode 100644 src/libcamera/ipa_module.cpp

Hi Paul,

Thank you for the patch.

On Tue, May 21, 2019 at 11:53:18AM -0400, Paul Elder wrote:
> Implement a class to wrap around an IPA module shared object.
> 
> For now, just load a struct IPAModuleInfo with symbol name
> ipaModuleInfo from an IPA module .so shared object.
> 
> Also provide a public header file including the struct IPAModuleInfo,
> structured such that both C and C++ IPA modules are supported.
> 
> Signed-off-by: Paul Elder <paul.elder@ideasonboard.com>
> ---
> Changes in v4:
> - added overloaded elfPointer to specify the size to check for in the
>   case that it cannot be obtained from the type (eg. char[size])
> - documentation formalization
> - other cosmetic changes
> 
> Changes in v3:
> - created public header file for IPAModuleInfo (and for handling C vs
>   C++ IPA modules)
> - made ELF loading/parsing functions static
> - got rid of bitClass_
> - other cosmetic changes
> 
> Changes in v2:
> - renamed LibLoader class to IPAModule
> - added documentation
> - added logging
> - check that bitness of the shared object is the same as libcamera
> - moved symbol loading ("init") to the constructor, and added isValid()
> - added elfPointer() to prevent segfaults when reading data from mmap
> - moved struct IPAModuleInfo out of IPAModule
> - rename getIPAModuleInfo() to IPAModuleInfo(), and make it return a
>   const reference
> - added munmap after the mmap
> 
>  include/libcamera/ipa/ipa_module_info.h |  31 +++
>  include/libcamera/meson.build           |   1 +
>  src/libcamera/include/ipa_module.h      |  35 +++
>  src/libcamera/ipa_module.cpp            | 290 ++++++++++++++++++++++++
>  src/libcamera/meson.build               |   2 +
>  5 files changed, 359 insertions(+)
>  create mode 100644 include/libcamera/ipa/ipa_module_info.h
>  create mode 100644 src/libcamera/include/ipa_module.h
>  create mode 100644 src/libcamera/ipa_module.cpp
> 
> diff --git a/include/libcamera/ipa/ipa_module_info.h b/include/libcamera/ipa/ipa_module_info.h
> new file mode 100644
> index 0000000..eae60f6
> --- /dev/null
> +++ b/include/libcamera/ipa/ipa_module_info.h
> @@ -0,0 +1,31 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2019, Google Inc.
> + *
> + * ipa_module.h - Image Processing Algorithm module

See v3 for a comment about this.

> + */
> +#ifndef __LIBCAMERA_IPA_MODULE_INFO_H__
> +#define __LIBCAMERA_IPA_MODULE_INFO_H__
> +
> +#ifdef __cplusplus
> +namespace libcamera {
> +#endif
> +
> +struct IPAModuleInfo {
> +	char name[256];
> +	unsigned int version;
> +};
> +
> +#ifdef __cplusplus
> +extern "C" {
> +#endif
> +extern const struct IPAModuleInfo ipaModuleInfo;
> +#ifdef __cplusplus
> +};
> +#endif
> +
> +#ifdef __cplusplus
> +}; /* namespace libcamera */
> +#endif
> +
> +#endif /* __LIBCAMERA_IPA_MODULE_INFO_H__ */
> diff --git a/include/libcamera/meson.build b/include/libcamera/meson.build
> index 83d226a..cb64f0c 100644
> --- a/include/libcamera/meson.build
> +++ b/include/libcamera/meson.build
> @@ -5,6 +5,7 @@ libcamera_api = files([
>      'event_dispatcher.h',
>      'event_notifier.h',
>      'geometry.h',
> +    'ipa/ipa_module_info.h',
>      'libcamera.h',
>      'object.h',
>      'request.h',
> diff --git a/src/libcamera/include/ipa_module.h b/src/libcamera/include/ipa_module.h
> new file mode 100644
> index 0000000..a13ea4a
> --- /dev/null
> +++ b/src/libcamera/include/ipa_module.h
> @@ -0,0 +1,35 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2019, Google Inc.
> + *
> + * ipa_module.h - Image Processing Algorithm module
> + */
> +#ifndef __LIBCAMERA_IPA_MODULE_H__
> +#define __LIBCAMERA_IPA_MODULE_H__
> +
> +#include <libcamera/ipa/ipa_module_info.h>
> +#include <string>
> +
> +namespace libcamera {
> +
> +class IPAModule
> +{
> +public:
> +	explicit IPAModule(const std::string &libPath);
> +
> +	bool isValid() const;
> +
> +	const struct IPAModuleInfo &info() const;
> +
> +private:
> +	struct IPAModuleInfo info_;
> +
> +	std::string libPath_;
> +	bool valid_;
> +
> +	int loadIPAModuleInfo(const char *libPath);

I'm surprised that the compiler didn't warn you that the declaration and
implementation don't match.

> +};
> +
> +} /* namespace libcamera */
> +
> +#endif /* __LIBCAMERA_IPA_MODULE_H__ */
> diff --git a/src/libcamera/ipa_module.cpp b/src/libcamera/ipa_module.cpp
> new file mode 100644
> index 0000000..c0e7c94
> --- /dev/null
> +++ b/src/libcamera/ipa_module.cpp
> @@ -0,0 +1,290 @@
> +/* SPDX-License-Identifier: LGPL-2.1-or-later */
> +/*
> + * Copyright (C) 2019, Google Inc.
> + *
> + * ipa_module.cpp - Image Processing Algorithm module
> + */
> +
> +#include "ipa_module.h"
> +
> +#include <elf.h>
> +#include <errno.h>
> +#include <fcntl.h>
> +#include <string.h>
> +#include <sys/mman.h>
> +#include <sys/stat.h>
> +#include <sys/types.h>
> +#include <unistd.h>
> +
> +#include "log.h"
> +
> +/**
> + * \file ipa_module.h
> + * \brief Image Processing Algorithm module
> + */
> +
> +/**
> + * \file ipa_module_info.h
> + * \brief Image Processing Algorithm module information
> + */
> +
> +namespace libcamera {
> +
> +LOG_DEFINE_CATEGORY(IPAModule)
> +
> +namespace {
> +
> +template<typename T>
> +typename std::remove_extent<T>::type *elfPointer(void *map, off_t offset,
> +						 size_t fileSize)
> +{
> +	size_t size = offset + sizeof(T);
> +	if (size > fileSize || size < sizeof(T))
> +		return nullptr;
> +
> +	return reinterpret_cast<typename std::remove_extent<T>::type *>
> +		(static_cast<char *>(map) + offset);
> +}

You could implement this function as

{
	return elfPointer<T>(map, offset, fileSize, sizeof(T));
}

to avoid duplicating code (you may need to reorder the two functions).

> +
> +template<typename T>
> +typename std::remove_extent<T>::type *elfPointer(void *map, off_t offset,
> +						 size_t fileSize, size_t tSize)

Maybe ptrSize instead of tSize ? Or objSize ?

> +{
> +	size_t size = offset + tSize;
> +	if (size > fileSize || size < tSize)
> +		return nullptr;
> +
> +	return reinterpret_cast<typename std::remove_extent<T>::type *>
> +		(static_cast<char *>(map) + offset);
> +}
> +
> +int elfVerifyIdent(void *map, size_t soSize)
> +{
> +	char *e_ident = elfPointer<char[EI_NIDENT]>(map, 0, soSize);
> +	if (!e_ident)
> +		return -ENOEXEC;
> +
> +	if (e_ident[EI_MAG0] != ELFMAG0 ||
> +	    e_ident[EI_MAG1] != ELFMAG1 ||
> +	    e_ident[EI_MAG2] != ELFMAG2 ||
> +	    e_ident[EI_MAG3] != ELFMAG3 ||
> +	    e_ident[EI_VERSION] != EV_CURRENT)
> +		return -ENOEXEC;
> +
> +	int bitClass = sizeof(unsigned long) == 4 ? ELFCLASS32 : ELFCLASS64;
> +	if (e_ident[EI_CLASS] != bitClass)
> +		return -ENOEXEC;
> +
> +	int a = 1;
> +	unsigned char endianness = *reinterpret_cast<char *>(&a) == 1
> +				 ? ELFDATA2LSB : ELFDATA2MSB;
> +	if (e_ident[EI_DATA] != endianness)
> +		return -ENOEXEC;
> +
> +	return 0;
> +}
> +
> +template<class ElfHeader, class SecHeader, class SymHeader>
> +int elfLoadSymbol(void *dst, size_t size, void *map, size_t soSize,
> +			  const char *symbol)
> +{
> +	ElfHeader *eHdr = elfPointer<ElfHeader>(map, 0, soSize);
> +	if (!eHdr)
> +		return -ENOEXEC;
> +
> +	off_t offset = eHdr->e_shoff + eHdr->e_shentsize * eHdr->e_shstrndx;
> +	SecHeader *sHdr = elfPointer<SecHeader>(map, offset, soSize);
> +	if (!sHdr)
> +		return -ENOEXEC;
> +	off_t shnameoff = sHdr->sh_offset;
> +
> +	/* Locate .dynsym section header. */
> +	SecHeader *dynsym = nullptr;
> +	for (unsigned int i = 0; i < eHdr->e_shnum; i++) {
> +		offset = eHdr->e_shoff + eHdr->e_shentsize * i;
> +		sHdr = elfPointer<SecHeader>(map, offset, soSize);
> +		if (!sHdr)
> +			return -ENOEXEC;
> +
> +		offset = shnameoff + sHdr->sh_name;
> +		char *name = elfPointer<char[8]>(map, offset, soSize);
> +		if (!name)
> +			return -ENOEXEC;
> +
> +		if (sHdr->sh_type == SHT_DYNSYM && !strcmp(name, ".dynsym")) {
> +			dynsym = sHdr;
> +			break;
> +		}
> +	}
> +
> +	if (dynsym == nullptr) {
> +		LOG(IPAModule, Error) << "ELF has no .dynsym section";
> +		return -ENOEXEC;
> +	}
> +
> +	offset = eHdr->e_shoff + eHdr->e_shentsize * dynsym->sh_link;
> +	sHdr = elfPointer<SecHeader>(map, offset, soSize);
> +	if (!sHdr)
> +		return -ENOEXEC;
> +	off_t dynsym_nameoff = sHdr->sh_offset;
> +
> +	/* Locate symbol in the .dynsym section. */
> +	SymHeader *targetSymbol = nullptr;
> +	unsigned int dynsym_num = dynsym->sh_size / dynsym->sh_entsize;
> +	for (unsigned int i = 0; i < dynsym_num; i++) {
> +		offset = dynsym->sh_offset + dynsym->sh_entsize * i;
> +		SymHeader *sym = elfPointer<SymHeader>(map, offset, soSize);
> +		if (!sym)
> +			return -ENOEXEC;
> +
> +		offset = dynsym_nameoff + sym->st_name;
> +		char *name = elfPointer<char>(map, offset, soSize,
> +					      strlen(symbol) + 1);
> +		if (!name)
> +			return -ENOEXEC;
> +
> +		if (!strcmp(name, symbol) &&
> +		    sym->st_info & STB_GLOBAL && sym->st_size == size) {
> +			targetSymbol = sym;
> +			break;
> +		}
> +	}
> +
> +	if (targetSymbol == nullptr) {
> +		LOG(IPAModule, Error) << "Symbol " << symbol << " not found";
> +		return -ENOEXEC;
> +	}
> +
> +	/* Locate and return data of symbol. */
> +	if (targetSymbol->st_shndx >= eHdr->e_shnum)
> +		return -ENOEXEC;
> +	offset = eHdr->e_shoff + targetSymbol->st_shndx * eHdr->e_shentsize;
> +	sHdr = elfPointer<SecHeader>(map, offset, soSize);
> +	if (!sHdr)
> +		return -ENOEXEC;
> +	offset = sHdr->sh_offset + (targetSymbol->st_value - sHdr->sh_addr);
> +	char *data = elfPointer<char>(map, offset, soSize, size);
> +	if (!data)
> +		return -ENOEXEC;
> +
> +	memcpy(dst, data, size);
> +
> +	return 0;
> +}
> +
> +} /* namespace */
> +
> +/**
> + * \struct IPAModuleInfo
> + * \brief Information of an IPA module
> + *
> + * This structure contains the information of an IPA module. It is loaded,
> + * read, and validated before anything else is loaded from the shared object.
> + *
> + * \var IPAModuleInfo::name
> + * \brief The name of the IPA module
> + *
> + * \var IPAModuleInfo::version
> + * \brief The version of the IPA module
> + *
> + * \todo abi compatability version
> + * \todo pipeline compatability matcher
> + */
> +
> +/**
> + * \class IPAModule
> + * \brief Wrapper around IPA module shared object
> + */
> +
> +/**
> + * \brief Construct an IPAModule instance
> + * \param[in] libPath path to IPA module shared object
> + *
> + * Loads the IPAModuleInfo from the IPA module shared object at libPath.
> + * The IPA module shared object file must be of the same endianness and
> + * bitness as libcamera.
> + *
> + * \todo load funtions from the IPA to be used by pipelines
> + *
> + * The caller shall call the isValid() method after constructing an
> + * IPAModule instance to verify the validity of the IPAModule.
> + */
> +IPAModule::IPAModule(const std::string &libPath)
> +	: libPath_(libPath), valid_(false)
> +{
> +	if (loadIPAModuleInfo() < 0)
> +		return;
> +
> +	valid_ = true;
> +}
> +
> +int IPAModule::loadIPAModuleInfo()
> +{
> +	int fd = open(libPath_.c_str(), O_RDONLY);
> +	if (fd < 0) {
> +		int ret = -errno;
> +		LOG(IPAModule, Error) << "Failed to open IPA library: "
> +				      << strerror(-ret);
> +		return ret;
> +	}
> +
> +	size_t soSize;
> +	void *map;
> +	struct stat st;
> +	int ret = fstat(fd, &st);
> +	if (ret < 0)
> +		goto close;
> +	soSize = st.st_size;
> +	map = mmap(NULL, soSize, PROT_READ, MAP_PRIVATE, fd, 0);
> +	if (map == MAP_FAILED) {
> +		ret = -errno;
> +		goto close;
> +	}
> +
> +	ret = elfVerifyIdent(map, soSize);
> +	if (ret)
> +		goto unmap;
> +
> +	if (sizeof(unsigned long) == 4)
> +		ret = elfLoadSymbol<Elf32_Ehdr, Elf32_Shdr, Elf32_Sym>
> +				   (&info_, sizeof(info_), map, soSize, "ipaModuleInfo");
> +	else
> +		ret = elfLoadSymbol<Elf64_Ehdr, Elf64_Shdr, Elf64_Sym>
> +				   (&info_, sizeof(info_), map, soSize, "ipaModuleInfo");
> +
> +unmap:
> +	munmap(map, soSize);
> +close:
> +	close(fd);
> +	return ret;
> +}
> +
> +/**
> + * \brief Check if the IPAModule instance is valid
> + *
> + * An IPAModule instance is valid if the IPA module shared object exists and
> + * the IPA module information it contains was successfully retrieved and
> + * validated.
> + *
> + * \return true if the the IPAModule is valid, false otherwise
> + */
> +bool IPAModule::isValid() const
> +{
> +	return valid_;
> +}
> +
> +/**
> + * \brief Retrieve the IPA module information
> + *
> + * The content of the IPA module information is loaded from the module,
> + * and is valid only if the module is valid (as returned by isValid()).
> + * Calling this function on an invalid module is an error.
> + *
> + * \return the IPA module information
> + */
> +const struct IPAModuleInfo &IPAModule::info() const
> +{
> +	return info_;
> +}
> +
> +} /* namespace libcamera */
> diff --git a/src/libcamera/meson.build b/src/libcamera/meson.build
> index 8796f49..e5b48f2 100644
> --- a/src/libcamera/meson.build
> +++ b/src/libcamera/meson.build
> @@ -10,6 +10,7 @@ libcamera_sources = files([
>      'event_notifier.cpp',
>      'formats.cpp',
>      'geometry.cpp',
> +    'ipa_module.cpp',
>      'log.cpp',
>      'media_device.cpp',
>      'media_object.cpp',
> @@ -31,6 +32,7 @@ libcamera_headers = files([
>      'include/device_enumerator_udev.h',
>      'include/event_dispatcher_poll.h',
>      'include/formats.h',
> +    'include/ipa_module.h',
>      'include/log.h',
>      'include/media_device.h',
>      'include/media_object.h',