Add proper test suite, add WIP daemon

Makefile

@@ -1,26 +1,48 @@
-DEPS_SRC:=$(shell find . -name "*.c" -not -name "test.c")
-DEPS:=$(DEPS_SRC:.c=.o)
+DEPS:=library.o ringbuf.o
 BIN:=libkvmchan.so
+LIBS=-lrt -pthread
+
+DAEMON_DEPS:=daemon/daemon.o daemon/libvirt.o daemon/util.o
+DAEMON_BIN:=kvmchand
+DAEMON_LIBS:=$(shell pkg-config --libs libvirt)
+
 TEST_DEPS:=test.o
 TEST_BIN:=test
+TEST_LIBS:=$(shell pkg-config --cflags --libs check)
 
 CFLAGS=-O2 -Wall -fpic -fvisibility=hidden -std=gnu99 -g -I. \
-	   -fstack-protector-strong -D_FORITY_SOURCE=2 -fstack-clash-protection
-LIBS=-lrt -pthread
+	   -fstack-protector-strong -D_FORITY_SOURCE=2
+
+COMPILER_NAME:=$(shell $(CC) --version |cut -d' ' -f1 |head -n1)
+ifneq ($(COMPILER_NAME),clang)
+# This flag is GCC-only
+CFLAGS += -fstack-clash-protection
+endif
 
-.PHONY all: library test
+
+.PHONY all: library daemon
 
 library: $(DEPS)
 	$(CC) -shared $(CFLAGS) $(DEPS) -o $(BIN) $(LIBS)
 
 %.o: %.c
 	$(CC) $(CFLAGS) -o $@ -c $<
 
-test: $(DEPS) $(TEST_DEPS)
-	$(CC) $(CFLAGS) $(DEPS) $(TEST_DEPS) -o $(TEST_BIN) $(LIBS)
+daemon: $(DAEMON_DEPS) $(DEPS)
+	$(CC) $(CFLAGS) $(DAEMON_DEPS) $(DEPS) -o $(DAEMON_BIN) $(LIBS) $(DAEMON_LIBS)
+
+build_test: $(DEPS) $(TEST_DEPS)
+	$(CC) $(CFLAGS) $(DEPS) $(TEST_DEPS) -o $(TEST_BIN) $(LIBS) $(TEST_LIBS)
+
+test: build_test
+	./$(TEST_BIN)
 
 clean:
 	rm -f $(DEPS)
 	rm -f $(BIN)
+	rm -f $(DAEMON_DEPS)
+	rm -f $(DAEMON_BIN)
 	rm -f $(TEST_BIN)
 	rm -f $(TEST_DEPS)
+
+print-%  : ; @echo $* = $($*)

README.md

@@ -7,7 +7,7 @@ As of now, only blocking, packet-based communication is supported.
 
 Overview
 -----
-libkvmchan uses a host/client architecture. Generally, the host is the KVM host system and the client is a virtual machine.
+libkvmchan uses a host/client architecture. Generally, the host is the KVM host system and the client is a virtual machine, but other configurations work too.
 Since libkvmchan uses `ivshmem`, all client machines must be configured with an `ivshmem` device in qemu/libvirt.
 This is described in the [Looking Glass Project's Documentation](https://looking-glass.hostfission.com/quickstart/linux/libvirt).
 
@@ -88,6 +88,12 @@ worst case, a malicious process can only get a trusted process to overwrite exis
 in the ring buffer and corrupt it. This should have no security consequences for the
 trusted process, since it will never read from any ring buffer that it writes to.
 
+Daemon
+------
+The included daemon is a WIP that will eventually allow automatic configuration of ivshmem shared memory channels
+and libkvmchan ring buffers by accessing the host's libvirt configuration interface. This will allow users
+to utilize libkvmchan without manually configuring the ivshmem devices attached to each VM, as well as
+dynamic allocation of >2 ring buffers per ivshmem channel.
 
 Why?
 ---

daemon/daemon-priv.h

@@ -0,0 +1,54 @@
+/**
+ * Copyright 2018-2019 Shawn Anastasio
+ *
+ * This file is part of libkvmchan.
+ *
+ * libkvmchan is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * libkvmchan is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with libkvmchan.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#ifndef KVMCHAN_DAEMON_PRIV_H
+#define KVMCHAN_DAEMON_PRIV_H
+
+#include <stdlib.h>
+#include <stdbool.h>
+
+enum log_level {
+    LOGL_INFO,
+    LOGL_WARN,
+    LOGL_ERROR
+};
+
+#ifdef __GNUC__
+#define log(level, fmt, ...) log_impl(level, __FILE__, __LINE__, fmt, ##__VA_ARGS__)
+#else
+#define log(level, fmt, ...) log_impl(level, __FILE__, __LINE__, __VA_ARGS__)
+#endif
+
+struct vec {
+    void **data;
+    size_t size;
+    size_t count;
+    void (*destructor)(void *);
+};
+
+void log_impl(enum log_level level, const char *file, int line, const char *fmt, ...);
+
+bool vec_init(struct vec *v, size_t initial_size, void (*destructor)(void *));
+bool vec_push_back(struct vec *v, void *element);
+void *vec_at(struct vec *v, size_t i);
+void vec_remove(struct vec *v, size_t i);
+
+int run_libvirt_loop(const char *);
+
+#endif // KVMCHAN_DAEMON_PRIV_H

daemon/daemon.c

@@ -0,0 +1,106 @@
+/**
+ * Copyright 2018-2019 Shawn Anastasio
+ *
+ * This file is part of libkvmchan.
+ *
+ * libkvmchan is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Lesser General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * libkvmchan is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with libkvmchan.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+/**
+ * This daemon interfaces with libvirt and allows VMs
+ * to query and create vchans which they can't do by
+ * themselves
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <stdbool.h>
+#include <errno.h>
+#include <assert.h>
+
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+
+#include "daemon-priv.h"
+
+// TODO: Support proper authentication and different libvirt hosts
+#define LIBVIRT_HOST_URI "qemu:///system"
+
+void daemonize() {
+    // Fork to background
+    pid_t child = fork();
+    if (child < 0) {
+        log(LOGL_ERROR, "Failed to fork to background!");
+        exit(EXIT_FAILURE);
+    } else if (child > 0) {
+        // Child forked successfully, parent can exit
+        exit(EXIT_SUCCESS);
+    }
+
+    // Change the file mode mask
+    umask(0);
+
+    // Create a new session
+    pid_t sid = setsid();
+    if (sid < 0) {
+        log(LOGL_ERROR, "Failed to set sid!");
+        exit(EXIT_FAILURE);
+    }
+
+    // Chdir to /
+    if (chdir("/") < 0) {
+        log(LOGL_ERROR, "Failed to chdir!");
+        exit(EXIT_FAILURE);
+    }
+
+    // Lastly, close all STDIO file descriptors
+    close(STDIN_FILENO);
+    close(STDOUT_FILENO);
+    close(STDERR_FILENO);
+}
+
+void show_help(const char *progname) {
+    fprintf(stderr, "Usage: %s [-h|-d]\n", progname);
+}
+
+int main(int argc, char **argv) {
+    bool daemon = false;
+    int opt;
+    while ((opt = getopt(argc, argv, "hd")) != -1) {
+        switch(opt) {
+            case 'h':
+                show_help(argv[0]);
+                return EXIT_SUCCESS;
+
+            case 'd':
+                daemon = true;
+                break;
+
+            default:
+                fprintf(stderr, "Unknown argument!\n");
+                show_help(argv[0]);
+                return EXIT_FAILURE;
+        }
+    }
+
+
+    // Daemonize if requested
+    if (daemon)
+        daemonize();
+
+    return run_libvirt_loop(LIBVIRT_HOST_URI);
+}