git.saurik.com Git - apple/libc.git/blame_incremental

... / ...

Commit	Line	Data
	1	/*
	2	* Copyright (c) 1987, 1993
	3	* The Regents of the University of California. All rights reserved.
	4	*
	5	* Redistribution and use in source and binary forms, with or without
	6	* modification, are permitted provided that the following conditions
	7	* are met:
	8	* 1. Redistributions of source code must retain the above copyright
	9	* notice, this list of conditions and the following disclaimer.
	10	* 2. Redistributions in binary form must reproduce the above copyright
	11	* notice, this list of conditions and the following disclaimer in the
	12	* documentation and/or other materials provided with the distribution.
	13	* 4. Neither the name of the University nor the names of its contributors
	14	* may be used to endorse or promote products derived from this software
	15	* without specific prior written permission.
	16	*
	17	* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
	18	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
	19	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
	20	* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
	21	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
	22	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
	23	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
	24	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
	25	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
	26	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
	27	* SUCH DAMAGE.
	28	*/
	29
	30	#if defined(LIBC_SCCS) && !defined(lint)
	31	static char sccsid[] = "@(#)getenv.c 8.1 (Berkeley) 6/4/93";
	32	#endif /* LIBC_SCCS and not lint */
	33	#include <sys/cdefs.h>
	34	__FBSDID("$FreeBSD: src/lib/libc/stdlib/getenv.c,v 1.8 2007/05/01 16:02:41 ache Exp $");
	35
	36	#include <os/lock_private.h>
	37	#include <stdlib.h>
	38	#include <stddef.h>
	39	#include <string.h>
	40	#include <crt_externs.h>
	41
	42	__private_extern__ char __findenv_locked(const char , int , char *);
	43	__private_extern__ void __environ_lock(void);
	44	__private_extern__ void __environ_unlock(void);
	45
	46	/*
	47	* __findenv_locked --
	48	* Returns pointer to value associated with name, if any, else NULL.
	49	* Sets offset to be the offset of the name/value combination in the
	50	* environmental array, for use by setenv(3) and unsetenv(3).
	51	* Explicitly removes '=' in argument name.
	52	*
	53	* This routine should be a static; don't use it.
	54	*/
	55	__private_extern__ char *
	56	__findenv_locked(name, offset, environ)
	57	const char *name;
	58	int *offset;
	59	char **environ;
	60	{
	61	int len, i;
	62	const char *np;
	63	char *p, cp;
	64
	65	if (name == NULL \|\| environ == NULL)
	66	return (NULL);
	67	for (np = name; np && np != '='; ++np)
	68	continue;
	69	len = np - name;
	70	for (p = environ; (cp = *p) != NULL; ++p) {
	71	for (np = name, i = len; i && *cp; i--)
	72	if (cp++ != np++)
	73	break;
	74	if (i == 0 && *cp++ == '=') {
	75	*offset = p - environ;
	76	return (cp);
	77	}
	78	}
	79	return (NULL);
	80	}
	81
	82	static os_unfair_lock __environ_lock_obj = OS_UNFAIR_LOCK_INIT;
	83	__private_extern__ void
	84	__environ_lock(void)
	85	{
	86	os_unfair_lock_lock_with_options(
	87	&__environ_lock_obj, OS_UNFAIR_LOCK_DATA_SYNCHRONIZATION);
	88	}
	89	__private_extern__ void
	90	__environ_unlock(void)
	91	{
	92	os_unfair_lock_unlock(&__environ_lock_obj);
	93	}
	94	__private_extern__ void
	95	__environ_lock_fork_child(void)
	96	{
	97	__environ_lock_obj = OS_UNFAIR_LOCK_INIT;
	98	}
	99
	100	/*
	101	* _getenvp -- SPI using an arbitrary pointer to string array (the array must
	102	* have been created with malloc) and an env state, created by _allocenvstate().
	103	* Returns ptr to value associated with name, if any, else NULL.
	104	*/
	105	char *
	106	_getenvp(const char name, char *envp, void state __unused)
	107	{
	108	// envp is passed as an argument, so the lock is not protecting everything
	109	int offset;
	110	__environ_lock();
	111	char result = (__findenv_locked(name, &offset, envp));
	112	__environ_unlock();
	113	return result;
	114	}
	115
	116	/*
	117	* getenv --
	118	* Returns ptr to value associated with name, if any, else NULL.
	119	*/
	120	char *
	121	getenv(name)
	122	const char *name;
	123	{
	124	int offset;
	125	__environ_lock();
	126	char result = __findenv_locked(name, &offset, _NSGetEnviron());
	127	__environ_unlock();
	128	return result;
	129	}