first commit 🎉

.gitignore

@@ -0,0 +1,3 @@
+pluginhost
+plugins/**/*.so
+**/*.o

Makefile

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+CC = clang
+CFLAGS = -std=c17 -g -Wall -O2 -fPIC
+
+EXEC = pluginhost
+
+SRCS = $(shell find src -name '*.c')
+OBJS = $(SRCS:.c=.o)
+
+PLUGINS = $(shell ls plugins)
+
+.PHONY: $(EXEC)
+
+all: $(EXEC) all_plugins
+
+$(EXEC): $(OBJS)
+	$(CC) $(CFLAGS) -o $(EXEC) $(OBJS)
+
+src/%.c.o: src/%.c
+	$(CC) $(CFLAGS) -o $@ -c $<
+
+all_plugins:
+	for plugin in $(PLUGINS); do \
+		$(MAKE) -C plugins/$$plugin; \
+	done
+
+clean:
+	rm -f $(EXEC) $(OBJS)
+	for plugin in $(PLUGINS); do \
+		$(MAKE) -C plugins/$$plugin clean; \
+	done

include/ariplugin.h

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+#ifndef ARIPLUGIN_H
+#define ARIPLUGIN_H
+
+int ari_plugin_load();
+int ari_plugin_unload();
+
+#endif // ARIPLUGIN_H

plugins/aridoodle/Makefile

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+CC = clang
+CFLAGS = -std=c17 -g -Wall
+LD = ld
+LDFLAGS = -shared -g -lc
+
+LIBRARY = aridoodle.so
+
+SRCS = $(shell find . -name '*.c')
+OBJS = $(SRCS:.c=.o)
+
+.PHONY: all
+
+all: $(LIBRARY)
+
+$(LIBRARY): $(OBJS)
+	$(LD) $(LDFLAGS) -o $(LIBRARY) $(OBJS)
+
+%.c.o: %.c
+	$(CC) $(CFLAGS) -o $@ -c $<
+
+clean:
+	rm -f $(OBJS) $(LIBRARY)

plugins/aridoodle/aridoodle.c

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+#include <stdio.h>
+#include "../../include/ariplugin.h"
+
+int ari_plugin_load() {
+    printf("hello from aridoodle :aridoodle:\n");
+    return 0;
+}
+
+int ari_plugin_unload() {
+    printf("aridoodle says byebye!\n");
+    return 0;
+}

plugins/test/Makefile

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+CC = clang
+CFLAGS = -std=c17 -g -Wall
+LD = ld
+LDFLAGS = -shared -g -lc
+
+LIBRARY = test.so
+
+SRCS = $(shell find . -name '*.c')
+OBJS = $(SRCS:.c=.o)
+
+.PHONY: all
+
+all: $(LIBRARY)
+
+$(LIBRARY): $(OBJS)
+	$(LD) $(LDFLAGS) -o $(LIBRARY) $(OBJS)
+
+%.c.o: %.c
+	$(CC) $(CFLAGS) -o $@ -c $<
+
+clean:
+	rm -f $(OBJS) $(LIBRARY)

plugins/test/test.c

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+#include <stdio.h>
+#include "../../include/ariplugin.h"
+
+int ari_plugin_load() {
+    printf("hello from test plugin!\n");
+    return 0;
+}
+
+int ari_plugin_unload() {
+    printf("test plugin unloaded successfully!\n");
+    return 0;
+}

src/main.c

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+#include <errno.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+#include <dlfcn.h>
+#include <sys/types.h>
+#include <dirent.h>
+#include <err.h>
+
+#define LIBRARY_PATH_FMT "plugins/%s/%s.so"
+
+typedef struct {
+    char name[256];
+    void *handle;
+
+    int (*func_load)(void);
+    int (*func_unload)(void);
+} Plugin;
+
+int main(int argc, char *argv[]) {
+    // find plugins
+    DIR *plugins_dir = opendir("plugins");
+    if (plugins_dir == NULL) {
+        errx(EXIT_FAILURE, "failed to read plugins directory");
+    }
+
+    struct dirent *plugin_ent;
+
+    size_t n_plugins = 0;
+    while ((plugin_ent = readdir(plugins_dir)) != NULL) {
+        if (!strcmp(".", plugin_ent->d_name))
+            continue;
+        if (!strcmp("..", plugin_ent->d_name))
+            continue;
+        n_plugins++;
+    }
+
+    rewinddir(plugins_dir);
+    Plugin plugins[n_plugins];
+    size_t n_plugins_ok = 0;
+
+    while ((plugin_ent = readdir(plugins_dir)) != NULL) {
+        if (!strcmp(".", plugin_ent->d_name))
+            continue;
+        if (!strcmp("..", plugin_ent->d_name))
+            continue;
+
+        char *error;
+
+        strcpy(plugins[n_plugins_ok].name, plugin_ent->d_name);
+        char *library_path = NULL;
+        int len = snprintf(library_path, 0, LIBRARY_PATH_FMT, plugins[n_plugins_ok].name, plugins[n_plugins_ok].name);
+
+        library_path = malloc(len);
+        sprintf(library_path, LIBRARY_PATH_FMT, plugins[n_plugins_ok].name, plugins[n_plugins_ok].name);
+
+        plugins[n_plugins_ok].handle = dlopen(library_path, RTLD_LAZY);
+        if (!plugins[n_plugins_ok].handle) {
+            errx(EXIT_FAILURE, "failed to load plugin: %s\n", dlerror());
+        }
+
+        dlerror(); // clear errors
+
+        plugins[n_plugins_ok].func_load = dlsym(plugins[n_plugins_ok].handle, "ari_plugin_load");
+        plugins[n_plugins_ok].func_unload = dlsym(plugins[n_plugins_ok].handle, "ari_plugin_unload");
+        
+        error = dlerror();
+        if (error != NULL) {
+            fprintf(stderr, "failed to initialise plugin \"%s\": %s\n", plugins[n_plugins_ok].name, error);
+            dlclose(plugins[n_plugins_ok].handle);
+            continue;
+        }
+
+        int code = plugins[n_plugins_ok].func_load();
+        if (code != EXIT_SUCCESS) {
+            fprintf(stderr, "warn: plugin \"%s\" returned code %d when loaded\n", plugins[n_plugins_ok].name, code);
+        }
+
+        free(library_path);
+
+        n_plugins_ok++;
+    }
+
+    printf("%ld plugins loaded.\n", n_plugins_ok);
+    printf("press any key to continue...");
+    getc(stdin);
+
+    for (int i = 0; i < n_plugins; i++) {
+        if (plugins[n_plugins_ok].handle == NULL) {
+            continue;
+        }
+
+        int code = plugins[i].func_unload();
+        if (code != EXIT_SUCCESS) {
+            fprintf(stderr, "warn: plugin \"%s\" returned code %d when unloaded\n", plugins[i].name, code);
+        }
+
+        dlclose(plugins[i].handle);
+    }
+
+    closedir(plugins_dir);
+
+    return 0;
+}