summaryrefslogtreecommitdiffstats
path: root/gl/lib/setenv.c
diff options
context:
space:
mode:
Diffstat (limited to 'gl/lib/setenv.c')
-rw-r--r--gl/lib/setenv.c390
1 files changed, 390 insertions, 0 deletions
diff --git a/gl/lib/setenv.c b/gl/lib/setenv.c
new file mode 100644
index 0000000..ebfd4e5
--- /dev/null
+++ b/gl/lib/setenv.c
@@ -0,0 +1,390 @@
+/* Copyright (C) 1992, 1995-2003, 2005-2022 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ This file 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.
+
+ This file 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 <https://www.gnu.org/licenses/>. */
+
+#if !_LIBC
+/* Don't use __attribute__ __nonnull__ in this compilation unit. Otherwise gcc
+ optimizes away the name == NULL test below. */
+# define _GL_ARG_NONNULL(params)
+
+# define _GL_USE_STDLIB_ALLOC 1
+# include <config.h>
+#endif
+
+#include <alloca.h>
+
+/* Specification. */
+#include <stdlib.h>
+
+#include <errno.h>
+#ifndef __set_errno
+# define __set_errno(ev) ((errno) = (ev))
+#endif
+
+#include <string.h>
+#if _LIBC || HAVE_UNISTD_H
+# include <unistd.h>
+#endif
+
+#if !_LIBC
+# include "malloca.h"
+#endif
+
+#if _LIBC || !HAVE_SETENV
+
+#if !_LIBC
+# define __environ 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
+
+/* 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__ || defined __clang__))
+# 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)
+{
+ char **ep;
+ 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)
+ {
+ /* It's easier to set errno to ENOMEM than to rely on the
+ 'malloc-posix' and 'realloc-posix' gnulib modules. */
+ __set_errno (ENOMEM);
+ 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 *) malloca (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
+ freea (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
+ freea (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 = malloca (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 = (char *) malloc (namelen + 1 + vallen);
+ if (np == NULL)
+ {
+#if defined USE_TSEARCH && !defined _LIBC
+ freea (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
+ freea (new_value);
+#endif
+ }
+
+ *ep = np;
+ }
+
+ UNLOCK;
+
+ return 0;
+}
+
+int
+setenv (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);
+}
+
+/* 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 */
+
+/* The rest of this file is called into use when replacing an existing
+ but buggy setenv. Known bugs include failure to diagnose invalid
+ name, and consuming a leading '=' from value. */
+#if HAVE_SETENV
+
+# undef setenv
+# if !HAVE_DECL_SETENV
+extern int setenv (const char *, const char *, int);
+# endif
+# define STREQ(a, b) (strcmp (a, b) == 0)
+
+int
+rpl_setenv (const char *name, const char *value, int replace)
+{
+ int result;
+ if (!name || !*name || strchr (name, '='))
+ {
+ errno = EINVAL;
+ return -1;
+ }
+ /* Call the real setenv even if replace is 0, in case implementation
+ has underlying data to update, such as when environ changes. */
+ result = setenv (name, value, replace);
+ if (result == 0 && replace && *value == '=')
+ {
+ char *tmp = getenv (name);
+ if (!STREQ (tmp, value))
+ {
+ int saved_errno;
+ size_t len = strlen (value);
+ tmp = malloca (len + 2);
+ /* Since leading '=' is eaten, double it up. */
+ *tmp = '=';
+ memcpy (tmp + 1, value, len + 1);
+ result = setenv (name, tmp, replace);
+ saved_errno = errno;
+ freea (tmp);
+ errno = saved_errno;
+ }
+ }
+ return result;
+}
+
+#endif /* HAVE_SETENV */
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-16 17:06:05 +0000