diff options
Diffstat (limited to 'gnulib/import/setenv.c')
| -rw-r--r-- | gnulib/import/setenv.c | 390 |
1 files changed, 390 insertions, 0 deletions
diff --git a/gnulib/import/setenv.c b/gnulib/import/setenv.c new file mode 100644 index 0000000..85c32cb --- /dev/null +++ b/gnulib/import/setenv.c @@ -0,0 +1,390 @@ +/* Copyright (C) 1992, 1995-2003, 2005-2016 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 3 of the License, 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, see <http://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__) +# 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 */ |