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+/* $OpenBSD: getenv.c,v 1.10 2010/08/23 22:31:50 millert Exp $ */
+/*
+ * 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.
+ * 3. 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.
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+char *__findenv(const char *name, int len, int *offset);
+
+/*
+ * __findenv --
+ * Returns pointer to value associated with name, if any, else NULL.
+ * Starts searching within the environmental array at offset.
+ * Sets offset to be the offset of the name/value combination in the
+ * environmental array, for use by putenv(3), setenv(3) and unsetenv(3).
+ * Explicitly removes '=' in argument name.
+ *
+ * This routine *should* be a static; don't use it.
+ */
+char *
+__findenv(const char *name, int len, int *offset)
+{
+ extern char **environ;
+ int i;
+ const char *np;
+ char **p, *cp;
+
+ if (name == NULL || environ == NULL)
+ return (NULL);
+ for (p = environ + *offset; (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);
+}
+
+/*
+ * getenv --
+ * Returns ptr to value associated with name, if any, else NULL.
+ */
+char *
+getenv(const char *name)
+{
+ int offset = 0;
+ const char *np;
+
+ for (np = name; *np && *np != '='; ++np)
+ ;
+ return (__findenv(name, (int)(np - name), &offset));
+}