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-rw-r--r--dlfcn/dlerror.c144
1 files changed, 144 insertions, 0 deletions
diff --git a/dlfcn/dlerror.c b/dlfcn/dlerror.c
new file mode 100644
index 0000000000..c43d511156
--- /dev/null
+++ b/dlfcn/dlerror.c
@@ -0,0 +1,144 @@
+/* Return error detail for failing <dlfcn.h> functions.
+   Copyright (C) 1995, 1996, 1997, 1998 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 <dlfcn.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <bits/libc-lock.h>
+
+/* Type for storing results of dynamic loading actions.  */
+struct dl_action_result
+  {
+    int errcode;
+    char *errstring;
+  };
+static struct dl_action_result last_result;
+static struct dl_action_result *static_buf;
+
+
+/* This is the key for the thread specific memory.  */
+static __libc_key_t key;
+
+/* Destructor for the thread-specific data.  */
+static void init (void);
+static void free_key_mem (void *mem);
+
+
+char *
+dlerror (void)
+{
+  static char *buf;
+  struct dl_action_result *result;
+
+  if (buf)
+    {
+      free (buf);
+      buf = NULL;
+    }
+
+  /* Get error string.  */
+  result = (struct dl_action_result *) __libc_getspecific (key);
+  if (result == NULL)
+    result = &last_result;
+
+  if (! result->errstring)
+    return NULL;
+
+  if (result->errcode == 0)
+    buf = result->errstring;
+  else
+    {
+      if (__asprintf (&buf, "%s: %s",
+		      result->errstring, strerror (result->errcode)) == -1)
+	buf = NULL;
+
+      /* We don't need the error string anymore.  */
+      free (result->errstring);
+    }
+
+  /* Reset the error indicator.  */
+  result->errstring = NULL;
+
+  return buf;
+}
+
+int
+internal_function
+_dlerror_run (void (*operate) (void *), void *args)
+{
+  __libc_once_define (static, once);
+  struct dl_action_result *result;
+
+  /* If we have not yet initialized the buffer do it now.  */
+  __libc_once (once, init);
+
+  /* Get error string and number.  */
+  if (static_buf != NULL)
+    result = static_buf;
+  else
+    {
+      /* We don't use the static buffer and so we have a key.  Use it
+	 to get the thread-specific buffer.  */
+      result = __libc_getspecific (key);
+      if (result == NULL)
+	{
+	  result = (struct dl_action_result *) calloc (1, sizeof (*result));
+	  if (result == NULL)
+	    /* We are out of memory.  Since this is no really critical
+	       situation we carry on by using the global variable.
+	       This might lead to conflicts between the threads but
+	       they soon all will have memory problems.  */
+	    result = &last_result;
+	  else
+	    /* Set the tsd.  */
+	    __libc_setspecific (key, result);
+	}
+    }
+
+  if (result->errstring != NULL)
+    /* Free the error string from the last failed command.  This can
+       happen if `dlerror' was not run after an error was found.  */
+    free (result->errstring);
+
+  result->errcode = _dl_catch_error (&result->errstring, operate, args);
+
+  return result->errstring != NULL;
+}
+
+
+/* Initialize buffers for results.  */
+static void
+init (void)
+{
+  if (__libc_key_create (&key, free_key_mem))
+    /* Creating the key failed.  This means something really went
+       wrong.  In any case use a static buffer which is better than
+       nothing.  */
+    static_buf = &last_result;
+}
+
+
+/* Free the thread specific data, this is done if a thread terminates.  */
+static void
+free_key_mem (void *mem)
+{
+  free (mem);
+  __libc_setspecific (key, NULL);
+}