diff options
Diffstat (limited to 'lib/putenv.c')
| -rw-r--r-- | lib/putenv.c | 196 |
1 files changed, 196 insertions, 0 deletions
diff --git a/lib/putenv.c b/lib/putenv.c new file mode 100644 index 0000000..b0d27e2 --- /dev/null +++ b/lib/putenv.c @@ -0,0 +1,196 @@ +/* Copyright (C) 1991, 1994, 1997-1998, 2000, 2003-2022 Free Software + Foundation, Inc. + + NOTE: The canonical source of this file is maintained with the GNU C + Library. Bugs can be reported to bug-glibc@prep.ai.mit.edu. + + 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 3 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/>. */ + +#include <config.h> + +/* Specification. */ +#include <stdlib.h> + +#include <stddef.h> + +/* Include errno.h *after* sys/types.h to work around header problems + on AIX 3.2.5. */ +#include <errno.h> +#ifndef __set_errno +# define __set_errno(ev) ((errno) = (ev)) +#endif + +#include <string.h> +#include <unistd.h> + +#if defined _WIN32 && ! defined __CYGWIN__ +# define WIN32_LEAN_AND_MEAN +# include <windows.h> +#endif + +#if _LIBC +# if HAVE_GNU_LD +# define environ __environ +# else +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 + +#if defined _WIN32 && ! defined __CYGWIN__ +/* Don't assume that UNICODE is not defined. */ +# undef SetEnvironmentVariable +# define SetEnvironmentVariable SetEnvironmentVariableA +#endif + +static int +_unsetenv (const char *name) +{ + size_t len; +#if !HAVE_DECL__PUTENV + char **ep; +#endif + + if (name == NULL || *name == '\0' || strchr (name, '=') != NULL) + { + __set_errno (EINVAL); + return -1; + } + + len = strlen (name); + +#if HAVE_DECL__PUTENV + { + int putenv_result; + char *name_ = malloc (len + 2); + memcpy (name_, name, len); + name_[len] = '='; + name_[len + 1] = 0; + putenv_result = _putenv (name_); + free (name_); + return putenv_result; + } +#else + + 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; +#endif +} + + +/* Put STRING, which is of the form "NAME=VALUE", in the environment. + If STRING contains no '=', then remove STRING from the environment. */ +int +putenv (char *string) +{ + const char *name_end = strchr (string, '='); + char **ep; + + if (name_end == NULL) + { + /* Remove the variable from the environment. */ + return _unsetenv (string); + } + +#if HAVE_DECL__PUTENV + /* Rely on _putenv to allocate the new environment. If other + parts of the application use _putenv, the !HAVE_DECL__PUTENV code + would fight over who owns the environ vector, causing a crash. */ + if (name_end[1]) + return _putenv (string); + else + { + /* _putenv ("NAME=") unsets NAME, so invoke _putenv ("NAME= ") + to allocate the environ vector and then replace the new + entry with "NAME=". */ + int putenv_result; + char *name_x = malloc (name_end - string + sizeof "= "); + if (!name_x) + return -1; + memcpy (name_x, string, name_end - string + 1); + name_x[name_end - string + 1] = ' '; + name_x[name_end - string + 2] = 0; + putenv_result = _putenv (name_x); + for (ep = environ; *ep; ep++) + if (strcmp (*ep, name_x) == 0) + { + *ep = string; + break; + } +# if defined _WIN32 && ! defined __CYGWIN__ + if (putenv_result == 0) + { + /* _putenv propagated "NAME= " into the subprocess environment; + fix that by calling SetEnvironmentVariable directly. */ + name_x[name_end - string] = 0; + putenv_result = SetEnvironmentVariable (name_x, "") ? 0 : -1; + errno = ENOMEM; /* ENOMEM is the only way to fail. */ + } +# endif + free (name_x); + return putenv_result; + } +#else + for (ep = environ; *ep; ep++) + if (strncmp (*ep, string, name_end - string) == 0 + && (*ep)[name_end - string] == '=') + break; + + if (*ep) + *ep = string; + else + { + static char **last_environ = NULL; + size_t size = ep - environ; + char **new_environ = malloc ((size + 2) * sizeof *new_environ); + if (! new_environ) + return -1; + new_environ[0] = string; + memcpy (new_environ + 1, environ, (size + 1) * sizeof *new_environ); + free (last_environ); + last_environ = new_environ; + environ = new_environ; + } + + return 0; +#endif +} |