Set up pseudo terminal and fork slave

slave.c

@@ -0,0 +1,67 @@
+#define _XOPEN_SOURCE 500
+#include "slave.h"
+#include <stdlib.h>
+#include <unistd.h>
+#include <errno.h>
+#include <string.h>
+
+#include <sys/stat.h>
+#include <fcntl.h>
+
+#define LOG_MODULE "slave"
+#define LOG_ENABLE_DBG 1
+#include "log.h"
+
+void
+slave_spawn(int ptmx)
+{
+    int pts = -1;
+    const char *pts_name = ptsname(ptmx);
+
+    if (grantpt(ptmx) == -1) {
+        LOG_ERRNO("failed to grantpt()");
+        goto err;
+    }
+    if (unlockpt(ptmx) == -1) {
+        LOG_ERRNO("failed to unlockpt()");
+        goto err;
+    }
+
+    close(ptmx);
+    ptmx = -1;
+
+    if (setsid() == -1) {
+        LOG_ERRNO("failed to setsid()");
+        goto err;
+    }
+
+    pts = open(pts_name, O_RDWR);
+    if (pts == -1) {
+        LOG_ERRNO("failed to open pseudo terminal slave device");
+        goto err;
+    }
+
+    if (dup2(pts, STDIN_FILENO) == -1 ||
+        dup2(pts, STDOUT_FILENO) == -1 ||
+        dup2(pts, STDERR_FILENO) == -1)
+    {
+        LOG_ERRNO("failed to dup stdin/stdout/stderr");
+        goto err;
+    }
+
+    close(pts);
+    pts = -1;
+
+    /* TODO: exec() */
+    const char *s = "hello world\n";
+    write(STDOUT_FILENO, s, strlen(s));
+
+    sleep(1000);
+
+err:
+    if (pts != -1)
+        close(pts);
+    if (ptmx != -1)
+        close(ptmx);
+    _exit(errno);
+}