Add Gnulib portability modules; update Gnulib files.

[bpt/guile.git] / lib / putenv.c

diff --git a/lib/putenv.c b/lib/putenv.c
new file mode 100644 (file)
index 0000000..53cc839
--- /dev/null
+++ b/lib/putenv.c
@@ -0,0 +1,132 @@
+/* Copyright (C) 1991, 1994, 1997-1998, 2000, 2003-2008
+   Free Software Foundation, Inc.
+
+   NOTE: The canonical source of this file is maintained with the GNU C
+   Library.  Bugs can be reported to bug-glibc@prep.ai.mit.edu.
+
+   This program is free software: you can redistribute it and/or modify it
+   under the terms of the GNU Lesser General Public License as published by the
+   Free Software Foundation; either version 3 of the License, or any
+   later version.
+
+   This program 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 Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public License
+   along with this program.  If not, see <http://www.gnu.org/licenses/>.  */
+
+#include <config.h>
+
+/* Specification.  */
+#include <stdlib.h>
+
+#include <stddef.h>
+
+/* Include errno.h *after* sys/types.h to work around header problems
+   on AIX 3.2.5.  */
+#include <errno.h>
+#ifndef __set_errno
+# define __set_errno(ev) ((errno) = (ev))
+#endif
+
+#include <string.h>
+#include <unistd.h>
+
+#if HAVE_GNU_LD
+# define environ __environ
+#else
+extern char **environ;
+#endif
+
+#if _LIBC
+/* This lock protects against simultaneous modifications of `environ'.  */
+# include <bits/libc-lock.h>
+__libc_lock_define_initialized (static, envlock)
+# define LOCK  __libc_lock_lock (envlock)
+# define UNLOCK        __libc_lock_unlock (envlock)
+#else
+# define LOCK
+# define UNLOCK
+#endif
+
+static int
+_unsetenv (const char *name)
+{
+  size_t len;
+  char **ep;
+
+  if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
+    {
+      __set_errno (EINVAL);
+      return -1;
+    }
+
+  len = strlen (name);
+
+  LOCK;
+
+  ep = environ;
+  while (*ep != NULL)
+    if (!strncmp (*ep, name, len) && (*ep)[len] == '=')
+      {
+       /* Found it.  Remove this pointer by moving later ones back.  */
+       char **dp = ep;
+
+       do
+         dp[0] = dp[1];
+       while (*dp++);
+       /* Continue the loop in case NAME appears again.  */
+      }
+    else
+      ++ep;
+
+  UNLOCK;
+
+  return 0;
+}
+
+
+/* Put STRING, which is of the form "NAME=VALUE", in the environment.
+   If STRING contains no `=', then remove STRING from the environment.  */
+int
+putenv (char *string)
+{
+  const char *const name_end = strchr (string, '=');
+  register size_t size;
+  register char **ep;
+
+  if (name_end == NULL)
+    {
+      /* Remove the variable from the environment.  */
+      return _unsetenv (string);
+    }
+
+  size = 0;
+  for (ep = environ; *ep != NULL; ++ep)
+    if (!strncmp (*ep, string, name_end - string) &&
+       (*ep)[name_end - string] == '=')
+      break;
+    else
+      ++size;
+
+  if (*ep == NULL)
+    {
+      static char **last_environ = NULL;
+      char **new_environ = (char **) malloc ((size + 2) * sizeof (char *));
+      if (new_environ == NULL)
+       return -1;
+      (void) memcpy ((void *) new_environ, (void *) environ,
+                    size * sizeof (char *));
+      new_environ[size] = (char *) string;
+      new_environ[size + 1] = NULL;
+      free (last_environ);
+      last_environ = new_environ;
+      environ = new_environ;
+    }
+  else
+    *ep = string;
+
+  return 0;
+}