From 2b81bf74baeaf734185fa4e2116b44b809ec9b74 Mon Sep 17 00:00:00 2001
From: Avril <flanchan@cumallover.me>
Date: Thu, 10 Mar 2022 12:39:47 +0000
Subject: [PATCH] Added sink program and Makefile
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Fortune for sink's current commit: Half blessing − 半吉
---
 .gitignore |  3 +++
 Makefile   | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
 sink.c     | 43 ++++++++++++++++++++++++++++++++++++
 3 files changed, 111 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 Makefile
 create mode 100644 sink.c

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..867ddb9
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+*.o
+sink
+sink-*
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..ba1925c
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,65 @@
+# Sinks all input to /dev/null
+PROJECT=sink
+
+SRC=$(wildcard *.c)
+OUTPUT=$(PROJECT)
+
+COMMON_FLAGS+= -W -Wall -Wextra -Wstrict-aliasing -fno-strict-aliasing
+
+TARGET_ARCH?=native
+ifneq ($(TARGET_ARCH),)
+	TARGET_ARCH:=$(addprefix -march=,$(TARGET_ARCH))
+endif
+RELEASE_CFLAGS+= $(TARGET_ARCH) -fgraphite -fopenmp -floop-parallelize-all -ftree-parallelize-loops=4 \
+	    -floop-interchange -ftree-loop-distribution -floop-strip-mine -floop-block \
+	    -fno-stack-check
+
+RELEASE_CFLAGS+= -O3 -flto
+RELEASE_LDFLAGS+= -Wl,-O3 -Wl,-flto
+
+DEBUG_CFLAGS+=-Og -g3 -ggdb -gz
+DEBUG_LDFLASG+=-Wl,-g
+
+CFLAGS   += $(COMMON_FLAGS) --std=gnu17
+LDFLAGS  +=
+
+OBJ   = $(SRC:.c=.o)
+
+STRIP=strip
+
+# Phonies
+
+.PHONY: $(OUTPUT)
+$(OUTPUT): $(PROJECT)-release
+	mv $< $@
+	$(STRIP) $@	
+
+
+.PHONY: release
+release: $(PROJECT)-release
+
+.PHONY: debug
+debug: $(PROJECT)-debug
+
+# Targets
+
+%.o: %.c
+	$(CC) -c $< $(CFLAGS) -o $@ $(LDFLAGS)
+
+$(PROJECT)-debug: CFLAGS+=$(DEBUG_CFLAGS)
+$(PROJECT)-debug: LDFLAGS+=$(DEBUG_LDFLAGS)
+$(PROJECT)-debug: $(OBJ)
+	$(CC) $^ -fwhole-program $(CFLAGS) -o $@ $(LDFLAGS)
+
+
+$(PROJECT)-release: CFLAGS+=$(RELEASE_CFLAGS)
+$(PROJECT)-release: LDFLAGS+=$(RELEASE_LDFLAGS)
+$(PROJECT)-release: $(OBJ)
+	$(CC) $^ -fwhole-program $(CFLAGS) -o $@ $(LDFLAGS)
+
+clean:
+	rm -f *.o
+	rm -f $(OUTPUT) $(PROJECT)-*
+
+
+	
diff --git a/sink.c b/sink.c
new file mode 100644
index 0000000..6682eee
--- /dev/null
+++ b/sink.c
@@ -0,0 +1,43 @@
+#include <stdio.h>
+#include <unistd.h>
+#include <fcntl.h>
+
+#define r_stdin 0
+#define r_stdout 1
+#define r_stderr 2
+
+#define LIKELY(e) __builtin_expect(!!(e), 1)
+#define UNLIKELY(e) __builtin_expect(!!(e), 0)
+
+static inline int dupall(int from)
+{
+	if(UNLIKELY(dup2(from, r_stdin) < 0)) {
+		perror("failed to dup2() stdin to sink");
+		return 1;
+	}
+	if(UNLIKELY(dup2(from, r_stdout) < 0)) {
+		perror("failed to dup2() stdout to sink");
+		return 2;
+	}
+#ifdef REPLACE_STDERR
+	if(UNLIKELY(dup2(from, r_stderr) < 0)) {
+		perror("failed to dup2() stderr to sink");
+#else
+	if(UNLIKELY(close(r_stderr) != 0)) {
+		perror("failed to close stderr");
+		
+#endif
+		return 3;
+	}
+	return 0;
+}
+
+int main(void)
+{
+	int null = open("/dev/null", O_RDWR);
+	if(UNLIKELY(null<0)) {
+		perror("failed to open /dev/null");
+		return 1;
+	}
+	return dupall(null);
+}