From cdf2238a33d63947ad70b0c26a3b4f4fe1f18454 Mon Sep 17 00:00:00 2001
From: Thomas Voss <mail@thomasvoss.com>
Date: Thu, 6 Jun 2024 21:13:34 +0200
Subject: Add new dummy program

---
 c/pipe/.gitignore |  1 +
 c/pipe/Makefile   |  8 ++++++
 c/pipe/pipe.c     | 75 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 84 insertions(+)
 create mode 100644 c/pipe/.gitignore
 create mode 100644 c/pipe/Makefile
 create mode 100644 c/pipe/pipe.c

diff --git a/c/pipe/.gitignore b/c/pipe/.gitignore
new file mode 100644
index 0000000..6b14dd0
--- /dev/null
+++ b/c/pipe/.gitignore
@@ -0,0 +1 @@
+pipe
diff --git a/c/pipe/Makefile b/c/pipe/Makefile
new file mode 100644
index 0000000..2d32167
--- /dev/null
+++ b/c/pipe/Makefile
@@ -0,0 +1,8 @@
+include ../base.mk
+
+all: pipe
+pipe: pipe.c
+	$(CC) $(CFLAGS) -lpthread -o $@ $<
+
+clean:
+	rm -f pipe
diff --git a/c/pipe/pipe.c b/c/pipe/pipe.c
new file mode 100644
index 0000000..f8ed9c7
--- /dev/null
+++ b/c/pipe/pipe.c
@@ -0,0 +1,75 @@
+#include <sys/wait.h>
+
+#include <err.h>
+#include <errno.h>
+#include <pthread.h>
+#include <stdlib.h>
+#include <time.h>
+#include <unistd.h>
+
+#define MILLISECOND (1e6)
+
+enum pipe_ends {
+	R,
+	W,
+};
+
+static void *work(void *);
+
+int
+main(void)
+{
+	static const char msg[] = u8"Olá Mundo!\n";
+
+	int fds[2];
+	if (pipe(fds) == -1)
+		err(1, "pipe");
+	if (write(fds[W], msg, sizeof(msg) - 1) == -1)
+		err(1, "write[1]");
+
+	pthread_t thrd;
+	if ((errno = pthread_create(&thrd, NULL, work, (void *)fds)) != 0)
+		err(1, "pthread_create");
+
+	struct timespec ts = {.tv_nsec = 500 * MILLISECOND};
+	if (nanosleep(&ts, NULL) == -1)
+		err(1, "nanosleep");
+
+	if (write(fds[W], msg, sizeof(msg) - 1) == -1)
+		err(1, "write[2]");
+
+	close(fds[W]);
+
+	if ((errno = pthread_join(thrd, NULL)) != 0)
+		err(1, "pthread_join");
+
+	return EXIT_SUCCESS;
+}
+
+void *
+work(void *_fds)
+{
+	int *fds = _fds;
+
+	struct timespec ts = {.tv_nsec = 250 * MILLISECOND};
+	if (nanosleep(&ts, NULL) == -1)
+		err(1, "nanosleep");
+
+	pid_t pid = fork();
+	if (pid == -1)
+		err(1, "fork");
+	if (pid == 0) {
+		close(STDIN_FILENO);
+		if (dup2(fds[R], STDIN_FILENO) == -1)
+			err(1, "dup2");
+		close(fds[R]);
+		close(fds[W]);
+		execlp("cat", "cat", NULL);
+		err(1, "exec");
+	}
+
+	close(fds[R]);
+	if (wait(NULL) == -1)
+		err(1, "wait");
+	return NULL;
+}
-- 
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