diff -uNr rappel-dd45bfa000efb89357d5c80a3a77550b96dee499/ptrace.c rappel-dd45bfa000efb89357d5c80a3a77550b96dee499.mod/ptrace.c
--- rappel-dd45bfa000efb89357d5c80a3a77550b96dee499/ptrace.c	2020-09-18 06:37:45.000000000 +0000
+++ rappel-dd45bfa000efb89357d5c80a3a77550b96dee499.mod/ptrace.c	2020-11-05 19:35:22.347935876 +0000
@@ -7,6 +7,7 @@
 #include <string.h>
 #include <unistd.h>
 
+#include <sys/stat.h>
 #include <sys/ptrace.h>
 #include <sys/types.h>
 #include <sys/wait.h>
@@ -103,6 +104,31 @@
 	return ret;
 }
 
+static int
+fexecve (int fd, char *const argv[], char *const envp[])
+{
+  if (fd < 0 || argv == NULL || envp == NULL)
+    {
+      errno = EINVAL;
+      return -1;
+    }
+
+  char buf[sizeof "/proc/self/fd/" + sizeof (int) * 3];
+  snprintf(buf, sizeof (buf), "/proc/self/fd/%d", fd);
+
+  execve(buf, argv, envp);
+
+  int save = errno;
+
+  struct stat st;
+  if (stat("/proc/self/fd", &st) != 0 && errno == ENOENT)
+    save = ENOSYS;
+
+  errno = save;
+
+  return -1;
+}
+
 void ptrace_child(
 		const int exe_fd)
 {