initial commit

diff --git a/README b/README
new file mode 100644 (file)
index 0000000..b910ac2
--- /dev/null
+++ b/README
@@ -0,0 +1,3 @@
+A crude UNIX tool that performs a bidirectional "cat" between
+stdin/stdout on one side and a file (opened for both reading and
+writing) on the other side.  Usually the file is a device.

diff --git a/bicat.c b/bicat.c
new file mode 100644 (file)
index 0000000..bc0ce99
--- /dev/null
+++ b/bicat.c
@@ -0,0 +1,48 @@
+#include <unistd.h>
+#include <sys/select.h>
+#include <sys/time.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <sys/stat.h>
+#include <fcntl.h>
+
+int main (int argc, char **argv) {
+  char buf[20];
+  int fd;
+  int retval;
+  int numread;
+  fd = open(argv[1], O_RDWR);
+  for(;;) {
+    fd_set rfds;
+    struct timeval tv;
+
+    FD_ZERO(&rfds);
+    FD_SET(STDIN_FILENO, &rfds);
+    FD_SET(fd, &rfds);
+
+    tv.tv_sec = 5;
+    tv.tv_usec = 0;
+
+    retval = select(fd+1, &rfds, NULL, NULL, &tv);
+
+    if (retval == -1)
+      perror("select()");
+    else if (retval) {
+      if (FD_ISSET(fd, &rfds)) {
+        numread = read(fd, buf, 1);
+        if (numread==0) return;
+        if (numread<0) perror("read()");
+        write(STDOUT_FILENO, buf, numread);
+      } else if (FD_ISSET(STDIN_FILENO, &rfds)) {
+        numread = read(STDIN_FILENO, buf, 1);
+        if (numread==0) return;
+        if (numread<0) perror("read()");
+        write(fd, buf, numread);
+      } else if (FD_ISSET(fd, &rfds)) {
+        perror("huh?\n");
+      }
+    } else {
+      //printf("No data within five seconds.\n");
+    }
+  }
+}