Initial lp.

src/cmd/lp/ipcopen.c

@@ -0,0 +1,92 @@
+#include <u.h>
+#include <libc.h>
+
+int ppid;
+
+/*
+ * predefined
+ */
+void pass(int from, int to);
+
+
+/*
+ *  Connect to given datakit port
+ */
+main(int argc, char *argv[])
+{
+	int fd0, fd1;
+	int cpid;
+	char c;
+	char *cp, *devdir, *buf;
+
+	if (argc != 4) {
+		fprint(2, "usage: %s destination network service\n", argv[0]);
+		exits("incorrect number of arguments");
+	}
+	if(!(cp = malloc((long)(strlen(argv[1])+strlen(argv[2])+strlen(argv[3])+8)))) {
+		perror("malloc");
+		exits("malloc failed");
+	}
+	sprint(cp, "%s!%s!%s", argv[2], argv[1], argv[3]);
+	if (dial(cp, &devdir, 0) < 0) {
+		fprint(2, "dialing %s\n", cp);
+		perror("dial");
+		exits("can't dial");
+	}
+
+	/*
+	 * Initialize the input fd, and copy bytes.
+	 */
+
+	if(!(buf = malloc((long)(strlen(devdir)+6)))) {
+		perror("malloc");
+		exits("malloc failed");
+	}
+	sprint(buf, "%s/data", devdir);
+	fd0=open(buf, OREAD);
+	fd1=open(buf, OWRITE);
+	if(fd0<0 || fd1<0) {
+		print("can't open", buf);
+		exits("can't open port");
+	}
+	ppid = getpid();
+	switch(cpid = fork()){
+	case -1:
+		perror("fork failed");
+		exits("fork failed");
+	case 0:
+		close(0);
+		close(fd1);
+		pass(fd0, 1);	/* from remote */
+		hangup(fd0);
+		close(1);
+		close(fd0);
+		exits("");
+	default:
+		close(1);
+		close(fd0);
+		pass(0, fd1);	/* to remote */
+		hangup(fd1);
+		close(0);
+		close(fd1);
+		exits("");
+	}
+}
+
+void
+pass(int from, int to)
+{
+	char buf[1024];
+	int ppid, cpid;
+	int n, tot = 0; 
+
+	while ((n=read(from, buf, sizeof(buf))) > 0) {
+		if (n==1 && tot==0 && *buf=='\0')
+			break;
+		tot += n;
+		if (write(to, buf, n)!=n) {
+			perror("pass write error");
+			exits("pass write error");
+		}
+	}
+}