| /* Copyright (C) 1992-2018 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, see |
| <http://www.gnu.org/licenses/>. */ |
| |
| #if HAVE_CONFIG_H |
| # include <config.h> |
| #endif |
| |
| /* Pacify GCC; see the commentary about VALLEN below. This is needed |
| at least through GCC 4.9.2. Pacify GCC for the entire file, as |
| there seems to be no way to pacify GCC selectively, only for the |
| place where it's needed. Do not use DIAG_IGNORE_NEEDS_COMMENT |
| here, as it's not defined yet. */ |
| #pragma GCC diagnostic ignored "-Wmaybe-uninitialized" |
| |
| #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 <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 (const char *name, const char *value, const char *combined, |
| int replace) |
| { |
| char **ep; |
| size_t size; |
| |
| /* Compute lengths before locking, so that the critical section is |
| less of a performance bottleneck. VALLEN is needed only if |
| COMBINED is null (unfortunately GCC is not smart enough to deduce |
| this; see the #pragma at the start of this file). Testing |
| COMBINED instead of VALUE causes setenv (..., NULL, ...) to dump |
| core now instead of corrupting memory later. */ |
| const size_t namelen = strlen (name); |
| size_t vallen; |
| if (combined == NULL) |
| vallen = strlen (value) + 1; |
| |
| 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 (__environ != last_environ) |
| memcpy ((char *) new_environ, (char *) __environ, |
| size * sizeof (char *)); |
| |
| new_environ[size] = NULL; |
| new_environ[size + 1] = NULL; |
| ep = new_environ + size; |
| |
| last_environ = __environ = new_environ; |
| } |
| if (*ep == NULL || replace) |
| { |
| char *np; |
| |
| /* Use the user string if given. */ |
| if (combined != NULL) |
| np = (char *) combined; |
| else |
| { |
| const size_t varlen = namelen + 1 + vallen; |
| #ifdef USE_TSEARCH |
| char *new_value; |
| int use_alloca = __libc_use_alloca (varlen); |
| if (__builtin_expect (use_alloca, 1)) |
| new_value = (char *) alloca (varlen); |
| else |
| { |
| new_value = malloc (varlen); |
| if (new_value == NULL) |
| { |
| UNLOCK; |
| return -1; |
| } |
| } |
| # 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 (__glibc_likely (np == NULL)) |
| #endif |
| { |
| #ifdef USE_TSEARCH |
| if (__glibc_unlikely (! use_alloca)) |
| np = new_value; |
| else |
| #endif |
| { |
| np = malloc (varlen); |
| if (__glibc_unlikely (np == NULL)) |
| { |
| UNLOCK; |
| return -1; |
| } |
| |
| #ifdef USE_TSEARCH |
| memcpy (np, new_value, varlen); |
| #else |
| memcpy (np, name, namelen); |
| np[namelen] = '='; |
| memcpy (&np[namelen + 1], value, vallen); |
| #endif |
| } |
| /* And remember the value. */ |
| STORE_VALUE (np); |
| } |
| #ifdef USE_TSEARCH |
| else |
| { |
| if (__glibc_unlikely (! use_alloca)) |
| free (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); |
| } |
| |
| 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; |
| if (ep != NULL) |
| 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 (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 |
| 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 |