1 files changed, 69 insertions, 0 deletions
diff --git a/c/fd-over-sock/server.c b/c/fd-over-sock/server.c
new file mode 100644
index 0000000..948e0ec
--- /dev/null
+++ b/c/fd-over-sock/server.c
@@ -0,0 +1,69 @@
+#include <sys/socket.h>
+#include <sys/un.h>
+
+#include <err.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#define die(...) err(EXIT_FAILURE, __VA_ARGS__)
+
+int
+main(void)
+{
+	int sfd;
+	socklen_t saddrlen = sizeof(struct sockaddr_un);
+	struct sockaddr_un saddr = {
+		.sun_family = AF_UNIX,
+		.sun_path = "foo.sock",
+	};
+
+	if ((sfd = socket(AF_UNIX, SOCK_STREAM, 0)) == -1)
+		die("socket");
+	if (bind(sfd, (struct sockaddr *)&saddr, saddrlen) == -1)
+		die("bind");
+	if (listen(sfd, 4) == -1)
+		die("listen");
+
+	for (;;) {
+		int cfd = accept(sfd, NULL, NULL);
+		if (cfd == -1)
+			die("accept");
+
+		struct msghdr msg = {0};
+		char m_buffer[sizeof(size_t) * 2];
+		struct iovec io = {
+			.iov_base = m_buffer,
+			.iov_len = sizeof(m_buffer),
+		};
+		msg.msg_iov = &io;
+		msg.msg_iovlen = 1;
+
+		char c_buffer[256];
+		msg.msg_control = c_buffer;
+		msg.msg_controllen = sizeof(c_buffer);
+
+		if (recvmsg(cfd, &msg, 0) == -1)
+			die("recvmsg");
+
+		struct cmsghdr *cmsg = CMSG_FIRSTHDR(&msg);
+		unsigned char *data = CMSG_DATA(cmsg);
+		int fd = *(int *)data;
+
+		size_t flen, mlen;
+		memcpy(&flen, m_buffer, sizeof(size_t));
+		memcpy(&mlen, m_buffer + sizeof(size_t), sizeof(size_t));
+
+		// printf("len: %zu\n", msg.msg_iov->iov_len);
+		write(STDOUT_FILENO, m_buffer + sizeof(size_t) * 2, mlen);
+		putchar('\n');
+
+		char buf[flen];
+		read(fd, buf, flen);
+		write(STDOUT_FILENO, buf, flen);
+		close(cfd);
+	}
+
+	return EXIT_SUCCESS;
+}