From 642b5fb0007b64c77d186fcb018d571152ee1d47 Mon Sep 17 00:00:00 2001
From: dzwdz
Date: Mon, 14 Aug 2023 18:51:07 +0200
Subject: reorganization: first steps

---
 src/libc/esemaphore.c | 56 +++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 src/libc/esemaphore.c

(limited to 'src/libc/esemaphore.c')

diff --git a/src/libc/esemaphore.c b/src/libc/esemaphore.c
new file mode 100644
index 0000000..2707d11
--- /dev/null
+++ b/src/libc/esemaphore.c
@@ -0,0 +1,56 @@
+#include <camellia/flags.h>
+#include <camellia/syscalls.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <esemaphore.h>
+
+void esem_signal(struct evil_sem *sem) {
+	_sys_write(sem->signal, NULL, 0, 0, 0);
+}
+
+void esem_wait(struct evil_sem *sem) {
+	_sys_read(sem->wait, NULL, 0, 0);
+}
+
+struct evil_sem *esem_new(int value) {
+	hid_t ends_wait[2], ends_signal[2];
+	struct evil_sem *sem;
+
+	if (value < 0) return NULL;
+	if (_sys_pipe(ends_wait, 0) < 0) return NULL;
+	if (_sys_pipe(ends_signal, 0) < 0) goto fail_signal;
+	if (!(sem = malloc(sizeof *sem))) goto fail_malloc;
+
+	if (!_sys_fork(FORK_NOREAP, NULL)) {
+		close(ends_signal[1]);
+		while (_sys_read(ends_signal[0], NULL, 0, 0) >= 0) {
+			if (!_sys_fork(FORK_NOREAP, NULL)) {
+				_sys_write(ends_wait[1], NULL, 0, 0, 0);
+				exit(0);
+			}
+		}
+		exit(0);
+	}
+	close(ends_signal[0]);
+	close(ends_wait[1]);
+
+	sem->wait = ends_wait[0];
+	sem->signal = ends_signal[1];
+
+	while (value--) esem_signal(sem);
+	return sem;
+
+fail_malloc:
+	close(ends_signal[0]);
+	close(ends_signal[1]);
+fail_signal:
+	close(ends_wait[0]);
+	close(ends_wait[1]);
+	return NULL;
+}
+
+void esem_free(struct evil_sem *sem) {
+	close(sem->wait);
+	close(sem->signal);
+	free(sem);
+}
-- 
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