From 2497c1392b81e093f4de2541a98746aebd449a7f Mon Sep 17 00:00:00 2001
From: Peter Wu <lekensteyn@gmail.com>
Date: Wed, 26 Sep 2012 15:04:18 +0200
Subject: Initial commit

---
 pipe.cpp | 56 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 56 insertions(+)
 create mode 100644 pipe.cpp

(limited to 'pipe.cpp')

diff --git a/pipe.cpp b/pipe.cpp
new file mode 100644
index 0000000..76cd19d
--- /dev/null
+++ b/pipe.cpp
@@ -0,0 +1,56 @@
+#include <iostream>
+#include <unistd.h>
+#include <cstdio>
+#include <sys/types.h>
+#include <sys/wait.h>
+#include <signal.h>
+#include <fcntl.h>
+#include <errno.h>
+
+#define BS 10
+
+int main(int argc, char **argv) {
+	int fds[2], fu[2];
+	if (argc <= 1){
+		std::cerr << "Usage: " << argv[0] << " program args..." << std::endl;
+		return 1;
+	}
+	if (pipe(fds) == -1 || pipe(fu) == -1) {
+		perror("pipe");
+		return 1;
+	}
+	pid_t p = fork();
+	if (p == 0) {
+		/*child*/
+		close(fu[1]);
+		close(fds[0]);
+		if (dup2(fu[0], STDIN_FILENO) == -1) perror("dup stdin");
+		if (dup2(fds[1], STDOUT_FILENO) == -1) perror("dup stdout");
+		execvp(argv[1], argv+1);
+		perror("Execvp");
+		_exit(42);
+	} else {
+		char buf[BS];
+		std::string in("meh\n\04");
+		int flags = fcntl(fds[0], F_GETFL);
+		fcntl(fds[0], F_SETFL, flags | O_NONBLOCK);
+		close(fds[1]);close(fu[0]);
+		do {
+			int r = read(fds[0], buf, BS);
+			if (r == -1 && errno == EWOULDBLOCK) ;
+			else if (r == -1) perror("read");
+			else if (r > 0) {
+				std::cout.write(buf, r);
+			}
+			if (write(fu[1], in.c_str(), in.size()) == -1) perror("write");
+			int status = 0;
+			if (waitpid(p, &status, WNOHANG) != 0) {
+				if (WIFEXITED(status) || WTERMSIG(status)) {
+					break;
+				}
+			}
+		} while (1);
+		kill(p, 15);
+	}
+	return 0;
+}
-- 
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