/* Copyright (c) 1993-2002 * 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 2, 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, write to the * Free Software Foundation, Inc., * 59 Temple Place - Suite 330, Boston, MA 02111-1307, 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 */