Initial release

.gitignore

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+/OBJ*

LICENSE

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+Copyright (c) 2016-2022 Tomas Paukrt
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+1. Redistributions of source code must retain the above copyright notice,
+   this list of conditions and the following disclaimer.
+
+2. Redistributions in binary form must reproduce the above copyright notice,
+   this list of conditions and the following disclaimer in the documentation
+   and/or other materials provided with the distribution.
+
+3. Neither the name of the copyright holder nor the names of its contributors
+   may be used to endorse or promote products derived from this software
+   without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
+LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
+CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
+GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
+LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Makefile

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+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright (C) 2022 Tomas Paukrt
+
+# list of static libraries to be built
+STATIC_LIBS = library
+
+# list of programs to be built
+PROGRAMS = server tool
+
+# list of additional dependencies
+DEPENDS = Makefile Setup.mk
+
+# target specific settings
+library_NAME = libxbus
+server_NAME = xbusd
+tool_NAME = xbus
+tool_LIBS = library
+
+# build setup and rules
+include Setup.mk
+include Rules.mk

NEWS.md

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+# Version history
+
+## 1.0.0 (2022-12-19)
+
+  * Initial release

README.md

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+# Simple Interprocess Communication Bus
+
+## Introduction
+
+  The xbus is a simple interprocess communication bus based on
+  publish/subscribe messaging over a UNIX domain socket that was
+  designed for use in embedded devices with limited memory.
+
+  It consists of a daemon that acts as a message broker, a tiny
+  library that provides basic functions for communication and
+  a command line tool that is useful for debugging as well as for
+  writing shell scripts.
+
+## Examples
+
+### Publisher
+
+  ```C
+  #include "xbus.h"
+
+  int main(void)
+  {
+    xbus_publish("sms/incoming", "Hello, World!");
+
+    return 0;
+  }
+  ```
+
+### Subscriber
+
+  ```C
+  #include <stdio.h>
+  #include "xbus.h"
+
+  int main(void)
+  {
+    char *topic, *payload;
+
+    xbus_subscribe("sms/*");
+
+    while (1) {
+      payload = xbus_receive(&topic);
+      printf("[%s]\n%s\n\n", topic, payload);
+    }
+  }
+  ```
+
+## Prerequisites
+
+  * GNU Make 3.81+
+  * GCC 4.9+
+
+## Build instructions
+
+  Execute the following command:
+
+  ```
+  make [DEBUG=1] [ASAN=1] [UBSAN=1] [V=1]
+  ```
+
+## Install instructions
+
+  Execute the following command:
+
+  ```
+  make install [DESTDIR=<dir>]
+  ```
+
+## Directory structure
+
+  ```
+  xbus
+   |
+   |--OBJ.*                     Output directories with built files
+   |
+   |--library                   IPC bus library (client API)
+   |
+   |--server                    IPC bus server (message broker)
+   |
+   |--tool                      IPC bus command line tool
+   |
+   |--LICENSE                   BSD 3-clause license
+   |--Makefile                  Main Makefile
+   |--NEWS.md                   Version history
+   |--README.md                 This file
+   |--Rules.mk                  Build rules
+   +--Setup.mk                  Build setup
+  ```
+
+## License
+
+  The code is available under the BSD 3-clause license.
+  See the `LICENSE` file for the full license text.

Rules.mk

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+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright (C) 2022 Tomas Paukrt
+
+# default subdirectory for object files
+OBJDIR ?= OBJ
+
+# default directories for installation
+BINDIR ?= /usr/bin
+LIBDIR ?= /usr/lib
+INCDIR ?= /usr/include
+
+# build verbosity
+ifeq ($(V),1)
+Q :=
+E := @true
+else
+Q := @
+E := @echo
+endif
+
+# build serialization
+ifneq ($(filter clean%, $(MAKECMDGOALS)),)
+.NOTPARALLEL:
+endif
+
+# default target
+all: build
+
+# target for building all binary files
+build:
+
+# target for installing all binary and header files
+install:
+
+# target for uninstalling all binary and header files
+uninstall:
+
+# target for cleaning all binary and temporary files
+clean:
+	$(Q) rm -rf $(firstword $(subst ., ,$(OBJDIR)))*
+
+# function to generate rules for building, installing and uninstalling a target binary file
+define generate-rules
+build: build-$(1)
+
+install: install-$(1)
+
+uninstall: uninstall-$(1)
+
+build-$(1): $(OBJDIR)/$(1)/$($(1)_FILE)
+
+install-$(1): build-$(1)
+	$(Q) $($(1)_PRE_INSTALL)
+	$(if $($(1)_PATH),
+	  $(E) "  CP  $(1)/$($(1)_FILE)"
+	  $(Q) install -D -m $($(1)_MODE) $(OBJDIR)/$(1)/$($(1)_FILE) $(DESTDIR)$($(1)_PATH)/$($(1)_FILE)
+	  $(foreach FILE, $($(1)_HEADER_LIST),
+	    $(E) "  CP  $(1)/$(FILE)"
+	    $(Q) install -D -m 644 $(1)/$(FILE) $(DESTDIR)$($(1)_HEADER_PATH)/$(FILE)
+	  )
+	)
+	$(Q) $($(1)_INSTALL)
+	$(Q) $($(1)_POST_INSTALL)
+
+uninstall-$(1):
+	$(Q) $($(1)_PRE_UNINSTALL)
+	$(Q) $($(1)_UNINSTALL)
+	$(if $($(1)_PATH),
+	  $(E) "  RM  $(1)/$($(1)_FILE)"
+	  $(Q) rm -f $(DESTDIR)$($(1)_PATH)/$($(1)_FILE)
+	  $(foreach FILE, $($(1)_HEADER_LIST),
+	    $(E) "  RM  $(1)/$(FILE)"
+	    $(Q) rm -f $(DESTDIR)$($(1)_HEADER_PATH)/$(FILE)
+	  )
+	)
+	$(Q) $($(1)_POST_UNINSTALL)
+
+clean-$(1):
+	$(Q) rm -rf $(OBJDIR)/$(1)
+
+$($(1)_OBJECT_DIRS):
+	$(Q) mkdir -p $$@
+
+$(OBJDIR)/$(1)/%.o: $(1)/%.c $(DEPENDS) | $($(1)_OBJECT_DIRS)
+	$(E) "  CC  $$(patsubst $(OBJDIR)/%,%,$$@)"
+	$(Q) $(CCACHE) $($(1)_COMPILER) -MMD -MP $(CPPFLAGS) $($(1)_CPPFLAGS) -fPIC $(CFLAGS) $($(1)_CFLAGS) -c $$< -o $$@
+
+$(OBJDIR)/$(1)/%.o: $(1)/%.cc $(DEPENDS) | $($(1)_OBJECT_DIRS)
+	$(E) "  CC  $$(patsubst $(OBJDIR)/%,%,$$@)"
+	$(Q) $(CCACHE) $($(1)_COMPILER) -MMD -MP $(CPPFLAGS) $($(1)_CPPFLAGS) -fPIC $(CXXFLAGS) $($(1)_CXXFLAGS) -c $$< -o $$@
+
+$(OBJDIR)/$(1)/%.o: $(1)/%.cpp $(DEPENDS) | $($(1)_OBJECT_DIRS)
+	$(E) "  CC  $$(patsubst $(OBJDIR)/%,%,$$@)"
+	$(Q) $(CCACHE) $($(1)_COMPILER) -MMD -MP $(CPPFLAGS) $($(1)_CPPFLAGS) -fPIC $(CXXFLAGS) $($(1)_CXXFLAGS) -c $$< -o $$@
+
+$(OBJDIR)/$(1)/$($(1)_NAME): $($(1)_OBJECT_LIST)
+	$(E) "  LD  $$(patsubst $(OBJDIR)/%,%,$$@)"
+	$(Q) $(CCACHE) $($(1)_LINKER) -pie $(LDFLAGS) $($(1)_LDFLAGS) -o $$@ $$(filter %.o, $$^) $($(1)_LDLIBS) $(LDLIBS)
+
+$(OBJDIR)/$(1)/$($(1)_NAME).so: $($(1)_OBJECT_LIST)
+	$(E) "  LD  $$(patsubst $(OBJDIR)/%,%,$$@)"
+	$(Q) $(CCACHE) $($(1)_LINKER) -shared $(LDFLAGS) $($(1)_LDFLAGS) -o $$@ $$(filter %.o, $$^) $($(1)_LDLIBS) $(LDLIBS)
+
+$(OBJDIR)/$(1)/$($(1)_NAME).a: $($(1)_OBJECT_LIST)
+	$(E) "  AR  $$(patsubst $(OBJDIR)/%,%,$$@)"
+	$(Q) rm -f $$@
+	$(Q) $(AR) rcs $$@ $$(filter %.o, $$^)
+
+-include $($(1)_DEPEND_LIST)
+endef
+
+# auxiliary function to set basic properties of a target binary file
+define set-properties
+$(eval $(1)_NAME ?= $(1))
+$(eval $(1)_PATH ?= $(2))
+$(eval $(1)_MODE ?= $(3))
+$(eval $(1)_FILE := $($(1)_NAME)$(4))
+$(eval $(1)_HEADER_PATH ?= $(INCDIR))
+$(eval $(1)_HEADER_LIST ?= $(if $(4), $(foreach EXT, h hh hpp, $(patsubst $(1)/%, %, $(foreach DIR, $(1) $(1)/*, $(wildcard $(DIR)/*.$(EXT)))))))
+$(eval $(1)_SOURCE_LIST ?= $(foreach EXT, c cc cpp, $(patsubst $(1)/%, %, $(foreach DIR, $(1) $(1)/*, $(sort $(wildcard $(DIR)/*.$(EXT)))))))
+$(eval $(1)_DEPEND_LIST := $(foreach EXT, c cc cpp, $(patsubst %.$(EXT), $(OBJDIR)/$(1)/%.d, $(filter %.$(EXT), $($(1)_SOURCE_LIST)))))
+$(eval $(1)_OBJECT_LIST := $(foreach EXT, c cc cpp, $(patsubst %.$(EXT), $(OBJDIR)/$(1)/%.o, $(filter %.$(EXT), $($(1)_SOURCE_LIST)))))
+$(eval $(1)_OBJECT_DIRS := $(sort $(dir $(addprefix $(OBJDIR)/$(1)/, $($(1)_SOURCE_LIST)))))
+$(eval $(1)_COMPILER    ?= $(if $(filter %.cc %.cpp, $($(1)_SOURCE_LIST)), $(CXX), $(CC)))
+$(eval $(1)_LINKER      ?= $($(1)_COMPILER))
+endef
+
+# auxiliary function to set dependencies of a target binary file on internal and external libraries
+define set-dependencies
+$(foreach LIB, $(filter $(wildcard *), $($(1)_LIBS)),
+  $(OBJDIR)/$(1)/$($(1)_FILE) : $(OBJDIR)/$(LIB)/$($(LIB)_FILE)
+  $(eval $(1)_CPPFLAGS += -I$(LIB))
+  $(eval $(1)_LDFLAGS  += -L$(OBJDIR)/$(LIB))
+  $(eval $(1)_LDLIBS   += $(patsubst lib%, -l%, $($(LIB)_NAME)))
+)
+$(foreach LIB, $(filter-out $(wildcard *), $($(1)_LIBS)),
+  $(eval $(1)_LDLIBS   += $(patsubst lib%, -l%, $(LIB)))
+)
+endef
+
+# generate auxiliary variables and build rules for each target binary file
+$(foreach DIR, $(PROGRAMS), $(eval $(call set-properties,$(DIR),$(BINDIR),755)))
+$(foreach DIR, $(SHARED_LIBS), $(eval $(call set-properties,$(DIR),$(LIBDIR),755,.so)))
+$(foreach DIR, $(STATIC_LIBS), $(eval $(call set-properties,$(DIR),$(LIBDIR),644,.a)))
+$(foreach DIR, $(STATIC_LIBS) $(SHARED_LIBS) $(PROGRAMS), $(eval $(call set-dependencies,$(DIR))))
+$(foreach DIR, $(STATIC_LIBS) $(SHARED_LIBS) $(PROGRAMS), $(eval $(call generate-rules,$(DIR))))

Setup.mk

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+# SPDX-License-Identifier: BSD-3-Clause
+# Copyright (C) 2022 Tomas Paukrt
+
+# ccache command
+CCACHE   := $(shell command -v ccache 2> /dev/null)
+
+# subdirectory for object files
+OBJDIR   := OBJ
+
+# basic compiler flags
+CFLAGS   += -Wall -Wextra -Wshadow -Wmissing-declarations -Wformat-security
+
+# extra compiler flags for debug and release build
+ifeq ($(DEBUG),1)
+OBJDIR   := $(OBJDIR).debug
+CFLAGS   += -O0 -ggdb
+CPPFLAGS += -DDEBUG
+else
+OBJDIR   := $(OBJDIR).release
+CFLAGS   += -O2
+LDFLAGS  += -s
+endif
+
+# extra compiler flags for address sanitizer
+ifeq ($(ASAN),1)
+OBJDIR   := $(OBJDIR).asan
+CFLAGS   += -fsanitize=address -fno-omit-frame-pointer
+LDFLAGS  += -fsanitize=address
+endif
+
+# extra compiler flags for undefined behavior sanitizer
+ifeq ($(UBSAN),1)
+OBJDIR   := $(OBJDIR).ubsan
+CFLAGS   += -fsanitize=undefined -fno-omit-frame-pointer
+LDFLAGS  += -fsanitize=undefined
+endif