--- Libc/Libc-391.1.21/stdlib/FreeBSD/getenv.c
+++ Libc/Libc-1725.40.4/stdlib/FreeBSD/getenv.c
@@ -10,10 +10,6 @@
  * 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.
- * 3. All advertising materials mentioning features or use of this software
- *    must display the following acknowledgement:
- *	This product includes software developed by the University of
- *	California, Berkeley and its contributors.
  * 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.
@@ -35,16 +31,21 @@
 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 1.4 2002/03/21 22:48:41 obrien Exp $");
+__FBSDID("$FreeBSD: src/lib/libc/stdlib/getenv.c,v 1.8 2007/05/01 16:02:41 ache Exp $");
 
+#include <errno.h>
+#include <os/lock_private.h>
 #include <stdlib.h>
 #include <stddef.h>
 #include <string.h>
+#include <crt_externs.h>
 
-inline char *__findenv(const char *, int *);
+#include "libc_private.h"
+
+__private_extern__ char *__findenv_locked(const char *, int *, char **);
 
 /*
- * __findenv --
+ * __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).
@@ -52,12 +53,9 @@
  *
  *	This routine *should* be a static; don't use it.
  */
-inline char *
-__findenv(name, offset)
-	const char *name;
-	int *offset;
+__private_extern__ char *
+__findenv_locked(const char *name, int *offset, char **environ)
 {
-	extern char **environ;
 	int len, i;
 	const char *np;
 	char **p, *cp;
@@ -79,15 +77,118 @@
 	return (NULL);
 }
 
+static os_unfair_lock __environ_lock_obj = OS_UNFAIR_LOCK_INIT;
+void
+environ_lock_np(void)
+{
+	os_unfair_lock_lock_with_options(
+			&__environ_lock_obj, OS_UNFAIR_LOCK_DATA_SYNCHRONIZATION);
+}
+void
+environ_unlock_np(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_np();
+	char *result = (__findenv_locked(name, &offset, *envp));
+	environ_unlock_np();
+	return result;
+}
+
 /*
  * getenv --
  *	Returns ptr to value associated with name, if any, else NULL.
  */
 char *
-getenv(name)
-	const char *name;
+getenv(const char *name)
 {
 	int offset;
+	environ_lock_np();
+	char *result = __findenv_locked(name, &offset, *_NSGetEnviron());
+	environ_unlock_np();
+	return result;
+}
 
-	return (__findenv(name, &offset));
+/*
+ * getenv_copy_np --
+ *	Returns ptr to copy of value associated with name, if any, else NULL.
+ *	Caller is responsible for freeing the return value.
+ *	Sets errno == ENOMEM and returns NULL if memory allocation fails.
+ *	Sets errno == EAGAIN and returns NULL if 5 attempts to copy the
+ *	string fails.
+ */
+char *
+getenv_copy_np(const char *name)
+{
+	/*
+	 * malloc() calls getenv() (which takes the environ_lock_np()), so
+	 * strdup() can not be called with environ_lock_np() held. Instead,
+	 * perform a two-step check for the length of the value (under lock),
+	 * then allocate a buffer, then try to copy the value into the buffer
+	 * (under lock). If the value of the environment variable changed such
+	 * that it no longer fits in the buffer, then try again up to four more
+	 * times. This algorithm is prescribed when using getenv_s() (ISO-C
+	 * Annex K), so this function abstracts that from the user since it is
+	 * difficult to implement correctly.
+	 */
+	unsigned attempts = 0;
+	char *result_buffer = NULL;
+	size_t result_buffer_length = 0;
+	int unused_offset;
+	char *value;
+	size_t value_length;
+
+	/* 1. Get the length of the value. */
+	environ_lock_np();
+	value = __findenv_locked(name, &unused_offset, *_NSGetEnviron());
+	value_length = value ? strlen(value) : 0;
+	environ_unlock_np();
+
+	if (!value)
+		return NULL;
+
+	do {
+		if (++attempts > 5) {
+			errno = EAGAIN;
+			return NULL;
+		}
+
+		/* 2. Allocate a buffer for the copy.  Round up to nearest/next 16 bytes. */
+		result_buffer_length = value_length + 1;
+		result_buffer_length += (16 - (result_buffer_length % 16));
+		result_buffer = (char *)reallocf((void *)result_buffer, result_buffer_length);
+		if (result_buffer == NULL) {
+			/* reallocf() sets errno = ENOMEM on failure. */
+			return NULL;
+		}
+
+		/* 3. Get the variable again and make a copy. */
+		environ_lock_np();
+		value = __findenv_locked(name, &unused_offset, *_NSGetEnviron());
+		value_length = value ? strlcpy(result_buffer, value, result_buffer_length) : 0;
+		environ_unlock_np();
+
+		if (!value)
+			return NULL;
+
+		/* 4. If value was too long for buffer, try again. */
+	} while (value_length >= result_buffer_length);
+
+	return result_buffer;
 }