/* * Copyright (c) 1987, 1993 * The Regents of the University of California. All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * 4. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. */ #if defined(LIBC_SCCS) && !defined(lint) static char sccsid[] = "@(#)getenv.c 8.1 (Berkeley) 6/4/93"; #endif /* LIBC_SCCS and not lint */ #include <sys/cdefs.h> __FBSDID("$FreeBSD: src/lib/libc/stdlib/getenv.c,v 1.8 2007/05/01 16:02:41 ache Exp $"); #include <os/lock_private.h> #include <stdlib.h> #include <stddef.h> #include <string.h> #include <crt_externs.h> __private_extern__ char *__findenv_locked(const char *, int *, char **); __private_extern__ void __environ_lock(void); __private_extern__ void __environ_unlock(void); /* * __findenv_locked -- * Returns pointer to value associated with name, if any, else NULL. * Sets offset to be the offset of the name/value combination in the * environmental array, for use by setenv(3) and unsetenv(3). * Explicitly removes '=' in argument name. * * This routine *should* be a static; don't use it. */ __private_extern__ char * __findenv_locked(name, offset, environ) const char *name; int *offset; char **environ; { int len, i; const char *np; char **p, *cp; if (name == NULL || environ == NULL) return (NULL); for (np = name; *np && *np != '='; ++np) continue; len = np - name; for (p = environ; (cp = *p) != NULL; ++p) { for (np = name, i = len; i && *cp; i--) if (*cp++ != *np++) break; if (i == 0 && *cp++ == '=') { *offset = p - environ; return (cp); } } return (NULL); } static os_unfair_lock __environ_lock_obj = OS_UNFAIR_LOCK_INIT; __private_extern__ void __environ_lock(void) { os_unfair_lock_lock_with_options( &__environ_lock_obj, OS_UNFAIR_LOCK_DATA_SYNCHRONIZATION); } __private_extern__ void __environ_unlock(void) { os_unfair_lock_unlock(&__environ_lock_obj); } __private_extern__ void __environ_lock_fork_child(void) { __environ_lock_obj = OS_UNFAIR_LOCK_INIT; } /* * _getenvp -- SPI using an arbitrary pointer to string array (the array must * have been created with malloc) and an env state, created by _allocenvstate(). * Returns ptr to value associated with name, if any, else NULL. */ char * _getenvp(const char *name, char ***envp, void *state __unused) { // envp is passed as an argument, so the lock is not protecting everything int offset; __environ_lock(); char *result = (__findenv_locked(name, &offset, *envp)); __environ_unlock(); return result; } /* * getenv -- * Returns ptr to value associated with name, if any, else NULL. */ char * getenv(name) const char *name; { int offset; __environ_lock(); char *result = __findenv_locked(name, &offset, *_NSGetEnviron()); __environ_unlock(); return result; }