Initial commit

Signed-off-by: Miquel Sabaté Solà <mssola@mssola.com>

1 files changed, 91 insertions, 0 deletions

diff --git a/src/main.c b/src/main.c
new file mode 100644
index 0000000..631b3c2
--- /dev/null
+++ b/src/main.c
@@ -0,0 +1,91 @@
+// SPDX-License-Identifier: GPL-3.0-or-later
+/*
+ * Copyright (C) 2024-Ω Miquel Sabaté Solà <mssola@mssola.com>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#define _GNU_SOURCE
+
+#include <errno.h>
+#include <sys/types.h>
+#include <sys/stat.h>
+#include <unistd.h>
+
+#include <pudc/print.h>
+#include <pudc/pudc.h>
+#include <pudc/compiler.h>
+
+/**
+ * Ensure that our current PID and TID are all 1, otherwise halt execution.
+ */
+void ensure_pid_tid_one(void)
+{
+	pid_t pid, tid;
+
+	pid = getpid();
+	if (pid != 1) {
+		pr_error(true, "'pudc' is supposed to be PID 1, but it is PID %d", pid);
+	}
+
+	tid = gettid();
+	if (tid != 1) {
+		pr_error(true, "'pudc' is supposed to be TID 1, but it is TID %d", tid);
+	}
+}
+
+/**
+ * Ensure that the given @path is an existing directory.
+ *
+ * NOTE: this function will halt execution in case of error.
+ */
+void ensure_dir(const char *const path)
+{
+	struct stat st;
+	int status = stat(path, &st);
+
+	if (!status) {
+		// Nothing to be done!
+		if (S_ISDIR(st.st_mode)) {
+			pr_debug("directory '%s' found", path);
+			return;
+		}
+
+		// It exists but it's not a directory, bail out.
+		pr_error(true, "'%s' exists and it's not a directory", path);
+	}
+
+	pr_error(true, "failed to stat '%s'", path);
+}
+
+__noreturn int main(void)
+{
+	pr_info("starting pudc v%s", PUDC_VERSION);
+
+	/*
+	 * Early checks.
+	 */
+	ensure_pid_tid_one();
+	ensure_dir("/run/pudc");
+
+	// TODO
+	halt();
+
+	/*
+	 * We should never reach this point, and if we do just halt. The second
+	 * 'halt' is just to make the compiler happy.
+	 */
+	pr_error(true, "pudc is no longer accepting requests. Halting execution..", "asd");
+	halt();
+}