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-rw-r--r--lib/setenv.c332
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diff --git a/lib/setenv.c b/lib/setenv.c
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+/* Copyright (C) 1992,1995-1999,2000-2003,2005-2007 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 2, or (at your option)
+ 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 General Public License for more details.
+
+ You should have received a copy of the GNU General Public License along
+ with this program; if not, write to the Free Software Foundation,
+ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
+
+#if !_LIBC
+# include <config.h>
+#endif
+#include <alloca.h>
+
+#include <errno.h>
+#ifndef __set_errno
+# define __set_errno(ev) ((errno) = (ev))
+#endif
+
+#include <stdlib.h>
+#include <string.h>
+#if _LIBC || HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+#if _LIBC || !HAVE_SETENV
+
+#if !_LIBC
+# include "allocsa.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 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>
+typedef int (*compar_fn_t) (const void *, const void *);
+
+/* 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 (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 || *ep == NULL)
+ {
+ char **new_environ;
+#ifdef USE_TSEARCH
+ char *new_value;
+#endif
+
+ /* We allocated this space; we can extend it. */
+ new_environ =
+ (char **) (last_environ == NULL
+ ? malloc ((size + 2) * sizeof (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 _LIBC
+ new_value = (char *) alloca (namelen + 1 + vallen);
+ __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
+ value, vallen);
+# else
+ new_value = (char *) allocsa (namelen + 1 + vallen);
+ if (new_value == NULL)
+ {
+ __set_errno (ENOMEM);
+ UNLOCK;
+ return -1;
+ }
+ memcpy (new_value, name, namelen);
+ new_value[namelen] = '=';
+ memcpy (&new_value[namelen + 1], value, vallen);
+# endif
+
+ new_environ[size] = KNOWN_VALUE (new_value);
+ if (new_environ[size] == NULL)
+#endif
+ {
+ new_environ[size] = (char *) malloc (namelen + 1 + vallen);
+ if (new_environ[size] == NULL)
+ {
+#if defined USE_TSEARCH && !defined _LIBC
+ freesa (new_value);
+#endif
+ __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 defined USE_TSEARCH && !defined _LIBC
+ freesa (new_value);
+#endif
+ }
+
+ 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
+ char *new_value;
+# ifdef _LIBC
+ new_value = alloca (namelen + 1 + vallen);
+ __mempcpy (__mempcpy (__mempcpy (new_value, name, namelen), "=", 1),
+ value, vallen);
+# else
+ new_value = allocsa (namelen + 1 + vallen);
+ if (new_value == NULL)
+ {
+ __set_errno (ENOMEM);
+ UNLOCK;
+ return -1;
+ }
+ memcpy (new_value, name, namelen);
+ new_value[namelen] = '=';
+ memcpy (&new_value[namelen + 1], value, vallen);
+# endif
+
+ np = KNOWN_VALUE (new_value);
+ if (np == NULL)
+#endif
+ {
+ np = malloc (namelen + 1 + vallen);
+ if (np == NULL)
+ {
+#if defined USE_TSEARCH && !defined _LIBC
+ freesa (new_value);
+#endif
+ __set_errno (ENOMEM);
+ 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);
+ }
+#if defined USE_TSEARCH && !defined _LIBC
+ freesa (new_value);
+#endif
+ }
+
+ *ep = np;
+ }
+
+ UNLOCK;
+
+ return 0;
+}
+
+int
+setenv (const char *name, const char *value, int replace)
+{
+ return __add_to_environ (name, value, NULL, replace);
+}
+
+/* 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 (void)
+{
+ 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
+static void
+free_mem (void)
+{
+ /* Remove all traces. */
+ clearenv ();
+
+ /* Now remove the search tree. */
+ __tdestroy (known_values, free);
+ known_values = NULL;
+}
+text_set_element (__libc_subfreeres, free_mem);
+
+
+# undef setenv
+# undef clearenv
+weak_alias (__setenv, setenv)
+weak_alias (__clearenv, clearenv)
+#endif
+
+#endif /* _LIBC || !HAVE_SETENV */
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