1 files changed, 353 insertions, 0 deletions
diff --git a/stdlib/setenv.c b/stdlib/setenv.c
new file mode 100644
index 0000000000..48aaecffe0
--- /dev/null
+++ b/stdlib/setenv.c
@@ -0,0 +1,353 @@
+/* Copyright (C) 1992,1995-2001,2004 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 Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 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
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, write to the Free
+   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+   02111-1307 USA.  */
+
+#if HAVE_CONFIG_H
+# include <config.h>
+#endif
+
+#include <errno.h>
+#if !_LIBC
+# if !defined errno && !defined HAVE_ERRNO_DECL
+extern int errno;
+# endif
+# define __set_errno(ev) ((errno) = (ev))
+#endif
+
+#if _LIBC || HAVE_STDLIB_H
+# include <stdlib.h>
+#endif
+#if _LIBC || HAVE_STRING_H
+# include <string.h>
+#endif
+#if _LIBC || HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+#if !_LIBC
+# define __environ	environ
+# ifndef HAVE_ENVIRON_DECL
+extern char **environ;
+# endif
+#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
+
+/* In the GNU C library we must keep the namespace clean.  */
+#ifdef _LIBC
+# define setenv __setenv
+# define unsetenv __unsetenv
+# define clearenv __clearenv
+# define tfind __tfind
+# define tsearch __tsearch
+#endif
+
+/* In the GNU C library implementation we try to be more clever and
+   allow arbitrarily many changes of the environment given that the used
+   values are from a small set.  Outside glibc this will eat up all
+   memory after a while.  */
+#if defined _LIBC || (defined HAVE_SEARCH_H && defined HAVE_TSEARCH \
+		      && defined __GNUC__)
+# define USE_TSEARCH	1
+# include <search.h>
+
+/* This is a pointer to the root of the search tree with the known
+   values.  */
+static void *known_values;
+
+# define KNOWN_VALUE(Str) \
+  ({									      \
+    void *value = tfind (Str, &known_values, (__compar_fn_t) strcmp);	      \
+    value != NULL ? *(char **) value : NULL;				      \
+  })
+# define STORE_VALUE(Str) \
+  tsearch (Str, &known_values, (__compar_fn_t) strcmp)
+
+#else
+# undef USE_TSEARCH
+
+# define KNOWN_VALUE(Str) NULL
+# define STORE_VALUE(Str) do { } while (0)
+
+#endif
+
+
+/* If this variable is not a null pointer we allocated the current
+   environment.  */
+static char **last_environ;
+
+
+/* This function is used by `setenv' and `putenv'.  The difference between
+   the two functions is that for the former must create a new string which
+   is then placed in the environment, while the argument of `putenv'
+   must be used directly.  This is all complicated by the fact that we try
+   to reuse values once generated for a `setenv' call since we can never
+   free the strings.  */
+int
+__add_to_environ (name, value, combined, replace)
+     const char *name;
+     const char *value;
+     const char *combined;
+     int replace;
+{
+  register char **ep;
+  register size_t size;
+  const size_t namelen = strlen (name);
+  const size_t vallen = value != NULL ? strlen (value) + 1 : 0;
+
+  LOCK;
+
+  /* We have to get the pointer now that we have the lock and not earlier
+     since another thread might have created a new environment.  */
+  ep = __environ;
+
+  size = 0;
+  if (ep != NULL)
+    {
+      for (; *ep != NULL; ++ep)
+	if (!strncmp (*ep, name, namelen) && (*ep)[namelen] == '=')
+	  break;
+	else
+	  ++size;
+    }
+
+  if (ep == NULL || __builtin_expect (*ep == NULL, 1))
+    {
+      char **new_environ;
+
+      /* We allocated this space; we can extend it.  */
+      new_environ = (char **) realloc (last_environ,
+				       (size + 2) * sizeof (char *));
+      if (new_environ == NULL)
+	{
+	  UNLOCK;
+	  return -1;
+	}
+
+      /* If the whole entry is given add it.  */
+      if (combined != NULL)
+	/* We must not add the string to the search tree since it belongs
+	   to the user.  */
+	new_environ[size] = (char *) combined;
+      else
+	{
+	  /* See whether the value is already known.  */
+#ifdef USE_TSEARCH
+# ifdef __GNUC__
+	  char new_value[namelen + 1 + vallen];
+# else
+	  char *new_value = (char *) alloca (namelen + 1 + vallen);
+# endif
+# ifdef _LIBC
+	  __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
+		     value, vallen);
+# else
+	  memcpy (new_value, name, namelen);
+	  new_value[namelen] = '=';
+	  memcpy (&new_value[namelen + 1], value, vallen);
+# endif
+
+	  new_environ[size] = KNOWN_VALUE (new_value);
+	  if (__builtin_expect (new_environ[size] == NULL, 1))
+#endif
+	    {
+	      new_environ[size] = (char *) malloc (namelen + 1 + vallen);
+	      if (__builtin_expect (new_environ[size] == NULL, 0))
+		{
+		  __set_errno (ENOMEM);
+		  UNLOCK;
+		  return -1;
+		}
+
+#ifdef USE_TSEARCH
+	      memcpy (new_environ[size], new_value, namelen + 1 + vallen);
+#else
+	      memcpy (new_environ[size], name, namelen);
+	      new_environ[size][namelen] = '=';
+	      memcpy (&new_environ[size][namelen + 1], value, vallen);
+#endif
+	      /* And save the value now.  We cannot do this when we remove
+		 the string since then we cannot decide whether it is a
+		 user string or not.  */
+	      STORE_VALUE (new_environ[size]);
+	    }
+	}
+
+      if (__environ != last_environ)
+	memcpy ((char *) new_environ, (char *) __environ,
+		size * sizeof (char *));
+
+      new_environ[size + 1] = NULL;
+
+      last_environ = __environ = new_environ;
+    }
+  else if (replace)
+    {
+      char *np;
+
+      /* Use the user string if given.  */
+      if (combined != NULL)
+	np = (char *) combined;
+      else
+	{
+#ifdef USE_TSEARCH
+# ifdef __GNUC__
+	  char new_value[namelen + 1 + vallen];
+# else
+	  char *new_value = (char *) alloca (namelen + 1 + vallen);
+# endif
+# ifdef _LIBC
+	  __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
+		     value, vallen);
+# else
+	  memcpy (new_value, name, namelen);
+	  new_value[namelen] = '=';
+	  memcpy (&new_value[namelen + 1], value, vallen);
+# endif
+
+	  np = KNOWN_VALUE (new_value);
+	  if (__builtin_expect (np == NULL, 1))
+#endif
+	    {
+	      np = malloc (namelen + 1 + vallen);
+	      if (__builtin_expect (np == NULL, 0))
+		{
+		  UNLOCK;
+		  return -1;
+		}
+
+#ifdef USE_TSEARCH
+	      memcpy (np, new_value, namelen + 1 + vallen);
+#else
+	      memcpy (np, name, namelen);
+	      np[namelen] = '=';
+	      memcpy (&np[namelen + 1], value, vallen);
+#endif
+	      /* And remember the value.  */
+	      STORE_VALUE (np);
+	    }
+	}
+
+      *ep = np;
+    }
+
+  UNLOCK;
+
+  return 0;
+}
+
+int
+setenv (name, value, replace)
+     const char *name;
+     const char *value;
+     int replace;
+{
+  if (name == NULL || *name == '\0' || strchr (name, '=') != NULL)
+    {
+      __set_errno (EINVAL);
+      return -1;
+    }
+
+  return __add_to_environ (name, value, NULL, replace);
+}
+
+int
+unsetenv (name)
+     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;
+}
+
+/* The `clearenv' was planned to be added to POSIX.1 but probably
+   never made it.  Nevertheless the POSIX.9 standard (POSIX bindings
+   for Fortran 77) requires this function.  */
+int
+clearenv ()
+{
+  LOCK;
+
+  if (__environ == last_environ && __environ != NULL)
+    {
+      /* We allocated this environment so we can free it.  */
+      free (__environ);
+      last_environ = NULL;
+    }
+
+  /* Clear the environment pointer removes the whole environment.  */
+  __environ = NULL;
+
+  UNLOCK;
+
+  return 0;
+}
+#ifdef _LIBC
+libc_freeres_fn (free_mem)
+{
+  /* Remove all traces.  */
+  clearenv ();
+
+  /* Now remove the search tree.  */
+  __tdestroy (known_values, free);
+  known_values = NULL;
+}
+
+# undef setenv
+# undef unsetenv
+# undef clearenv
+weak_alias (__setenv, setenv)
+weak_alias (__unsetenv, unsetenv)
+weak_alias (__clearenv, clearenv)
+#endif