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-rw-r--r--sysdeps/gnu/eval.c138
1 files changed, 138 insertions, 0 deletions
diff --git a/sysdeps/gnu/eval.c b/sysdeps/gnu/eval.c
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+/* You don't really want to know what this hack is for.
+ Copyright (C) 1996, 1997 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Library General Public License as
+ published by the Free Software Foundation; either version 2 of the
+ License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Library General Public License for more details.
+
+ You should have received a copy of the GNU Library General Public
+ License along with the GNU C Library; see the file COPYING.LIB. If not,
+ write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ Boston, MA 02111-1307, USA. */
+
+#include <stdio.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.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;
+
+ if (args[0] == NULL)
+ {
+ static const char unknown[] = "Unknown function\n";
+ write (1, unknown, sizeof unknown - 1);
+ return NULL;
+ }
+
+ /* 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) || *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 (__getdelim (&buf, &bufsz, '\n', stdin) > 0)
+ {
+ char *p = buf;
+ eval (&p);
+ }
+
+ exit (0);
+}