add epty.* to extend _pty.*

stdout/stderr independence for child process

cli/epty.c

@@ -0,0 +1,45 @@
+#include <stdlib.h>
+
+#include "mkpty.h"
+
+#define PIPE_READ 0
+#define PIPE_WRITE 1
+
+/* Allocate a PTY and fork, giving fdmx (master) to the parent
+ * and binding the child's stdin/stdout to fds (slave).
+ * Return value is indentical to fork(2).
+ * NOTE: This function is my alternative to GLibC's
+ * NOTE: forkpty() function. It exists as a learning resource.
+ * REF: https://sourceware.org/git/glibc.git -> ./login/forkpty.c
+ */
+pid_t forkepty(int *fdmx, int *fderr) {
+  // master/slave, and stderr pipe fds
+  int epipe[2];
+  pid_t pid;
+
+  if (pipe(epipe) == -1)
+    return EXIT_FAILURE;
+  switch (pid = forkmkpty(fdmx)) {
+  case -1:
+    /* forkmkpty() will close fdmx/fds for us */
+    close(epipe[PIPE_READ]);
+    close(epipe[PIPE_WRITE]);
+    return -1;
+  case 0:
+    /* Child Process */
+    /* forkmkpty() will close fdmx for us */
+    close(epipe[PIPE_READ]);
+    BIND(epipe[PIPE_WRITE], STDERR_FILENO);
+    break;
+
+  default:
+    /* Parent Process */
+    /* forkmkpty() will close fds for us */
+    close(epipe[PIPE_WRITE]);
+    *fderr = epipe[PIPE_READ];
+    break;
+  }
+
+  /* Both Processes */
+  return pid;
+}

cli/epty.h

@@ -0,0 +1,8 @@
+#ifndef DORNE_EPTY_H
+#define DORNE_EPTY_H
+
+#include <sys/types.h>
+
+pid_t forkepty(int *fdmx, int *fderr);
+
+#endif /* DORNE_EPTY_H */