checkpoint

fm/libconf.c

@@ -0,0 +1,193 @@
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <stdarg.h>
+
+#include <linux/limits.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+
+#define PATHS_NO 3
+
+static char temp[PATH_MAX]            = {0};
+static int  valid_paths               = 0;
+static char paths[PATHS_NO][PATH_MAX] = {0}; // 0: xdg, 1: fallback, 2: global
+
+static const mode_t CONFDIR_MODE = S_IRWXU | S_IRWXU | S_IRWXU | S_IRWXU;
+
+static void err(const char *fmt, ...)
+{
+	va_list ap;
+	va_start(ap, fmt);
+
+	fprintf(stderr, "[libconf]: ");
+	vfprintf(stderr, fmt, ap);
+	fprintf(stderr, "\n");
+
+	va_end(ap);
+}
+
+// implements "mkdir -p"
+static int mkdir_p(const char *path)
+{
+	char tmp_path[PATH_MAX] = {0};
+	strncpy(tmp_path, path, PATH_MAX - 1);
+	struct stat st;
+
+	for (char *tk = strtok(tmp_path, "/"); tk != NULL; tk = strtok(NULL, "/")) {
+		if (tk != tmp_path) {
+			tk[-1] = '/';
+		}
+
+		if (stat(tmp_path, &st)) {
+			if (errno != ENOENT) {
+				err("could not stat() %s: %s",
+				    tmp_path,
+				    strerror(errno));
+				return 1;
+			}
+
+			if (mkdir(tmp_path, CONFDIR_MODE)) {
+				err("could not mkdir() %s: %s",
+				    tmp_path,
+				    strerror(errno));
+				return 1;
+			}
+		} else if (!S_ISDIR(st.st_mode)) {
+			err("could not create directory %s: file exists but it is "
+			    "not a directory",
+			    tmp_path);
+			return 1;
+		}
+	}
+	return 0;
+}
+
+// TODO: add a way to add a custom directory to the paths, for example via an
+//       environment variable
+// TODO: maybe add a LIBCONF_PATH that overrides the defaults
+/* default paths are:
+ * 1. ${XDG_CONFIG_HOME}/libconf/appid.d/
+ * 2. ${HOME}/.config/libconf/appid.d/
+ * 3. etc/libconf/appid.d/
+ */
+static int fill_paths(const char *id)
+{
+	// TODO: verify id
+	if (id == NULL) {
+		err("must provide a valid app id");
+		return 1;
+	}
+
+	const char *xdg = getenv("XDG_CONFIG_HOME");
+	if (xdg != NULL) {
+		snprintf(paths[0], PATH_MAX, "%s/libconf/%s.d", xdg, id);
+	}
+
+	const char *home = getenv("HOME");
+	if (home) {
+		snprintf(temp, PATH_MAX, "%s/.config/libconf/%s.d", home, id);
+
+		if (mkdir_p(temp) == 0) {
+			strcpy(paths[1], temp);
+		}
+	}
+
+	// do not create global config path since most likely we don't have
+	// the necessary permissions to do so
+	snprintf(paths[2], PATH_MAX, "/etc/libconf/%s.d", id);
+
+	for (size_t i = 0; i < PATHS_NO; i++) {
+		printf("paths[%ld] = %s\n", i, paths[i]);
+	}
+
+	valid_paths = 1;
+
+	return 0;
+}
+
+// get config file path
+const char *lcnf_get_conf_file(const char *id, const char *name, int global)
+{
+	static char str[PATH_MAX] = {0};
+
+	if (id == NULL) {
+		return NULL;
+	}
+
+	if (!valid_paths) {
+		if (fill_paths(id)) {
+			return NULL;
+		}
+	}
+
+	// quick path for global config file
+	if (global && paths[2][0] != '\0') {
+		snprintf(str, PATH_MAX, "%s/%s", paths[2], name);
+		return str;
+	}
+
+	int found = 0;
+	for (size_t i = 0; i < PATHS_NO; i++) {
+		if (paths[i][0] == '\0') {
+			continue;
+		}
+
+		struct stat st;
+		snprintf(str, PATH_MAX, "%s/%s", paths[i], name);
+
+		if (stat(str, &st) && errno != ENOENT) {
+			err("could not stat %s: %s", str, strerror(errno));
+		}
+
+		if (S_ISREG(st.st_mode)) {
+			found = 1;
+			break;
+		}
+	}
+
+	return found ? str : NULL;
+}
+
+// get config file directory path
+const char *lcnf_get_conf_dir(const char *id, int global)
+{
+	if (id == NULL) {
+		return NULL;
+	}
+
+	if (global) {
+		return paths[2][0] != '\0' ? paths[2] : NULL;
+	}
+
+	if (paths[0][0] != '\0') {
+		return paths[0];
+	} else if (paths[1][0] != '\0') {
+		return paths[1];
+	} else {
+		return NULL;
+	}
+}
+
+// TODO: watch directory for file updates
+int lcnf_watch_conf_dir(const char *id, int global);
+
+// TODO: collect all files into a temporary one, useful for when you have multiple
+//       configuration files like 00-foo.conf, 01-bar.conf and 99-baz.conf
+const char *lcnf_collect_conf_files(const char *id, int global);
+
+#if 1
+
+int main(void)
+{
+	const char *p = lcnf_get_conf_file("pippo", "pippo.toml", 0);
+	if (p) {
+		printf("config found: %s\n", p);
+	} else {
+		printf("config not found\n");
+	}
+	return 0;
+}
+
+#endif

fm/libconf.h

@@ -0,0 +1,7 @@
+#ifndef LIBCONF_H_
+#define LIBCONF_H_
+
+const char *lcnf_get_conf_file(const char *id, const char *name, int global);
+const char *lcnf_get_conf_dir(const char *id, int global);
+
+#endif