1 files changed, 110 insertions, 0 deletions
diff --git a/elf/eval.c b/elf/eval.c
new file mode 100644
index 0000000..91415bb
--- /dev/null
+++ b/elf/eval.c
@@ -0,0 +1,110 @@
+#include <stdio.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <dlfcn.h>
+
+static void *funcall (char **stringp);
+static void *eval (char **stringp);
+
+static void *
+funcall (char **stringp)
+{
+  void *args[strlen (*stringp)], **ap = args;
+  void *argcookie = &args[1];
+
+  do
+    {
+      /* Evaluate the next token.  */
+      *ap++ = eval (stringp);
+
+      /* Whitespace is irrelevant.  */
+      while (isspace (**stringp))
+	++*stringp;
+
+      /* Terminate at closing paren or end of line.  */
+    } while (**stringp != '\0' && **stringp != ')');
+  if (**stringp != '\0')
+    /* Swallow closing paren.  */
+    ++*stringp;
+
+  /* Do it to it.  */
+  __builtin_return (__builtin_apply (args[0],
+				     &argcookie,
+				     (char *) ap - (char *) &args[1]));
+}
+
+static void *
+eval (char **stringp)
+{
+  void *value;
+  char *p = *stringp, c;
+
+  /* Whitespace is irrelevant.  */
+  while (isspace (*p))
+    ++p;
+
+  switch (*p)
+    {
+    case '"':
+      /* String constant.  */
+      value = ++p;
+      do
+	if (*p == '\\')
+	  {
+	    switch (*strcpy (p, p + 1))
+	      {
+	      case 't':
+		*p = '\t';
+		break;
+	      case 'n':
+		*p = '\n';
+		break;
+	      }
+	    ++p;
+	  }
+      while (*p != '\0' && *p++ != '"');
+      if (p[-1] == '"')
+	p[-1] = '\0';
+      break;
+
+    case '(':
+      *stringp = ++p;
+      return funcall (stringp);
+
+    default:
+      /* Try to parse it as a number.  */
+      value = (void *) strtol (p, stringp, 0);
+      if (*stringp != p)
+	return value;
+
+      /* Anything else is a symbol that produces its address.  */
+      value = p;
+      do
+	++p;
+      while (*p != '\0' && !isspace (*p) && !ispunct (*p));
+      c = *p;
+      *p = '\0';
+      value = dlsym (NULL, value);
+      *p = c;
+      break;
+    }
+
+  *stringp = p;
+  return value;
+}
+
+
+void
+_start (void)
+{
+  char *buf = NULL;
+  size_t bufsz = 0;
+
+  while (getline (&buf, &bufsz, stdin) > 0)
+    {
+      char *p = buf;
+      eval (&p);
+    }
+
+  exit (0);
+}