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+/* Copyright (c) 2008, 2009
+ * Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de)
+ * Michael Schroeder (mlschroe@immd4.informatik.uni-erlangen.de)
+ * Micah Cowan (micah@cowan.name)
+ * Sadrul Habib Chowdhury (sadrul@users.sourceforge.net)
+ * Copyright (c) 1993-2002, 2003, 2005, 2006, 2007
+ * Juergen Weigert (jnweiger@immd4.informatik.uni-erlangen.de)
+ * Michael Schroeder (mlschroe@immd4.informatik.uni-erlangen.de)
+ * Copyright (c) 1987 Oliver Laumann
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3, or (at your option)
+ * any later version.
+ *
+ * This program 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 General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program (see the file COPYING); if not, see
+ * https://www.gnu.org/licenses/, or contact Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02111-1301 USA
+ *
+ ****************************************************************
+ */
+
+/*
+ * putenv -- put value into environment
+ *
+ * Usage: i = putenv (string)
+ * int i;
+ * char *string;
+ *
+ * where string is of the form <name>=<value>.
+ * If "value" is 0, then "name" will be deleted from the environment.
+ * Putenv returns 0 normally, -1 on error (not enough core for malloc).
+ *
+ * Putenv may need to add a new name into the environment, or to
+ * associate a value longer than the current value with a particular
+ * name. So, to make life simpler, putenv() copies your entire
+ * environment into the heap (i.e. malloc()) from the stack
+ * (i.e. where it resides when your process is initiated) the first
+ * time you call it.
+ *
+ * HISTORY
+ * 3-Sep-91 Michael Schroeder (mlschroe). Modified to behave as
+ * as putenv.
+ * 16-Aug-91 Tim MacKenzie (tym) at Monash University. Modified for
+ * use in screen (iScreen) (ignores final int parameter)
+ * 14-Oct-85 Michael Mauldin (mlm) at Carnegie-Mellon University
+ * Ripped out of CMU lib for Rob-O-Matic portability
+ * 20-Nov-79 Steven Shafer (sas) at Carnegie-Mellon University
+ * Created for VAX. Too bad Bell Labs didn't provide this. It's
+ * unfortunate that you have to copy the whole environment onto the
+ * heap, but the bookkeeping-and-not-so-much-copying approach turns
+ * out to be much hairier. So, I decided to do the simple thing,
+ * copying the entire environment onto the heap the first time you
+ * call putenv(), then doing realloc() uniformly later on.
+ */
+
+#include "config.h"
+
+#ifdef NEEDPUTENV
+
+#if defined(__STDC__)
+# define __P(a) a
+#else
+# define __P(a) ()
+#endif
+
+char *malloc __P((int));
+char *realloc __P((char *, int));
+void free __P((char *));
+int sprintf __P((char *, char *, ...));
+
+#define EXTRASIZE 5 /* increment to add to env. size */
+
+static int envsize = -1; /* current size of environment */
+extern char **environ; /* the global which is your env. */
+
+static int findenv __P((char *)); /* look for a name in the env. */
+static int newenv __P((void)); /* copy env. from stack to heap */
+static int moreenv __P((void)); /* incr. size of env. */
+
+int
+unsetenv(name)
+char *name;
+{
+ register int i;
+
+ if (envsize < 0)
+ { /* first time putenv called */
+ if (newenv() < 0) /* copy env. to heap */
+ return -1;
+ }
+ i = findenv(name);
+ if (i < 0)
+ return 0; /* Already here */
+
+ free(environ[i]);
+ if (envsize > 0)
+ envsize--;
+ for (; environ[i]; i++)
+ environ[i] = environ[i+1];
+ return 0; /* Already here */
+}
+
+int
+putenv(string)
+char *string;
+{
+ register int i;
+ register char *p;
+
+ if (envsize < 0)
+ { /* first time putenv called */
+ if (newenv() < 0) /* copy env. to heap */
+ return -1;
+ }
+
+ i = findenv(string); /* look for name in environment */
+
+ if (i < 0)
+ { /* name must be added */
+ for (i = 0; environ[i]; i++);
+ if (i >= (envsize - 1))
+ { /* need new slot */
+ if (moreenv() < 0)
+ return -1;
+ }
+ p = malloc(strlen(string) + 1);
+ if (p == 0) /* not enough core */
+ return -1;
+ environ[i + 1] = 0; /* new end of env. */
+ }
+ else
+ { /* name already in env. */
+ p = realloc(environ[i], strlen(string) + 1);
+ if (p == 0)
+ return -1;
+ }
+ sprintf(p, "%s", string); /* copy into env. */
+ environ[i] = p;
+
+ return 0;
+}
+
+static int
+findenv(name)
+char *name;
+{
+ register char *namechar, *envchar;
+ register int i, found;
+
+ found = 0;
+ for (i = 0; environ[i] && !found; i++)
+ {
+ envchar = environ[i];
+ namechar = name;
+ while (*namechar && *namechar != '=' && (*namechar == *envchar))
+ {
+ namechar++;
+ envchar++;
+ }
+ found = ((*namechar == '\0' || *namechar == '=') && *envchar == '=');
+ }
+ return found ? i - 1 : -1;
+}
+
+static int
+newenv()
+{
+ register char **env, *elem;
+ register int i, esize;
+
+ for (i = 0; environ[i]; i++)
+ ;
+ esize = i + EXTRASIZE + 1;
+ env = (char **)malloc(esize * sizeof (elem));
+ if (env == 0)
+ return -1;
+
+ for (i = 0; environ[i]; i++)
+ {
+ elem = malloc(strlen(environ[i]) + 1);
+ if (elem == 0)
+ return -1;
+ env[i] = elem;
+ strcpy(elem, environ[i]);
+ }
+
+ env[i] = 0;
+ environ = env;
+ envsize = esize;
+ return 0;
+}
+
+static int
+moreenv()
+{
+ register int esize;
+ register char **env;
+
+ esize = envsize + EXTRASIZE;
+ env = (char **)realloc((char *)environ, esize * sizeof (*env));
+ if (env == 0)
+ return -1;
+ environ = env;
+ envsize = esize;
+ return 0;
+}
+
+#endif /* NEEDPUTENV */
+