4.4BSD/usr/src/contrib/emacs-18.57/src/environ.c
/* Environment-hacking for GNU Emacs subprocess
Copyright (C) 1986 Free Software Foundation, Inc.
This file is part of GNU Emacs.
GNU Emacs 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 1, or (at your option)
any later version.
GNU Emacs 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 GNU Emacs; see the file COPYING. If not, write to
the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
#include "config.h"
#include "lisp.h"
#ifdef MAINTAIN_ENVIRONMENT
#ifdef VMS
you lose -- this is un*x-only
#endif
/* alist of (name-string . value-string) */
Lisp_Object Venvironment_alist;
extern char **environ;
void
set_environment_alist (str, val)
register Lisp_Object str, val;
{
register Lisp_Object tem;
tem = Fassoc (str, Venvironment_alist);
if (NULL (tem))
if (NULL (val))
;
else
Venvironment_alist = Fcons (Fcons (str, val), Venvironment_alist);
else
if (NULL (val))
Venvironment_alist = Fdelq (tem, Venvironment_alist);
else
XCONS (tem)->cdr = val;
}
static void
initialize_environment_alist ()
{
register unsigned char **e, *s;
extern char *index ();
for (e = (unsigned char **) environ; *e; e++)
{
s = (unsigned char *) index (*e, '=');
if (s)
set_environment_alist (make_string (*e, s - *e),
build_string (s + 1));
}
}
unsigned char *
getenv_1 (str, ephemeral)
register unsigned char *str;
int ephemeral; /* if ephmeral, don't need to gc-proof */
{
register Lisp_Object env;
int len = strlen (str);
for (env = Venvironment_alist; CONSP (env); env = XCONS (env)->cdr)
{
register Lisp_Object car = XCONS (env)->car;
register Lisp_Object tem = XCONS (car)->car;
if ((len == XSTRING (tem)->size) &&
(!bcmp (str, XSTRING (tem)->data, len)))
{
/* Found it in the lisp environment */
tem = XCONS (car)->cdr;
if (ephemeral)
/* Caller promises that gc won't make him lose */
return XSTRING (tem)->data;
else
{
register unsigned char **e;
unsigned char *s;
int ll = XSTRING (tem)->size;
/* Look for element in the original unix environment */
for (e = (unsigned char **) environ; *e; e++)
if (!bcmp (str, *e, len) && *(*e + len) == '=')
{
s = *e + len + 1;
if (strlen (s) >= ll)
/* User hasn't either hasn't munged it or has set it
to something shorter -- we don't have to cons */
goto copy;
else
goto cons;
};
cons:
/* User has setenv'ed it to a diferent value, and our caller
isn't guaranteeing that he won't stash it away somewhere.
We can't just return a pointer to the lisp string, as that
will be corrupted when gc happens. So, we cons (in such
a way that it can't be freed -- though this isn't such a
problem since the only callers of getenv (as opposed to
those of egetenv) are very early, before the user -could-
have frobbed the environment. */
s = (unsigned char *) xmalloc (ll + 1);
copy:
bcopy (XSTRING (tem)->data, s, ll + 1);
return (s);
}
}
}
return ((unsigned char *) 0);
}
/* unsigned -- stupid delcaration in lisp.h */ char *
getenv (str)
register unsigned char *str;
{
return ((char *) getenv_1 (str, 0));
}
unsigned char *
egetenv (str)
register unsigned char *str;
{
return (getenv_1 (str, 1));
}
#if (1 == 1) /* use caller-alloca versions, rather than callee-malloc */
int
size_of_current_environ ()
{
register int size;
Lisp_Object tem;
tem = Flength (Venvironment_alist);
size = (XINT (tem) + 1) * sizeof (unsigned char *);
/* + 1 for environment-terminating 0 */
for (tem = Venvironment_alist; !NULL (tem); tem = XCONS (tem)->cdr)
{
register Lisp_Object str, val;
str = XCONS (XCONS (tem)->car)->car;
val = XCONS (XCONS (tem)->car)->cdr;
size += (XSTRING (str)->size +
XSTRING (val)->size +
2); /* 1 for '=', 1 for '\000' */
}
return size;
}
void
get_current_environ (memory_block)
unsigned char **memory_block;
{
register unsigned char **e, *s;
register int len;
register Lisp_Object tem;
e = memory_block;
tem = Flength (Venvironment_alist);
s = (unsigned char *) memory_block
+ (XINT (tem) + 1) * sizeof (unsigned char *);
for (tem = Venvironment_alist; !NULL (tem); tem = XCONS (tem)->cdr)
{
register Lisp_Object str, val;
str = XCONS (XCONS (tem)->car)->car;
val = XCONS (XCONS (tem)->car)->cdr;
*e++ = s;
len = XSTRING (str)->size;
bcopy (XSTRING (str)->data, s, len);
s += len;
*s++ = '=';
len = XSTRING (val)->size;
bcopy (XSTRING (val)->data, s, len);
s += len;
*s++ = '\000';
}
*e = 0;
}
#else
/* dead code (this function mallocs, caller frees) superseded by above (which allows caller to use alloca) */
unsigned char **
current_environ ()
{
unsigned char **env;
register unsigned char **e, *s;
register int len, env_len;
Lisp_Object tem;
Lisp_Object str, val;
tem = Flength (Venvironment_alist);
env_len = (XINT (tem) + 1) * sizeof (char *);
/* + 1 for terminating 0 */
len = 0;
for (tem = Venvironment_alist; !NULL (tem); tem = XCONS (tem)->cdr)
{
str = XCONS (XCONS (tem)->car)->car;
val = XCONS (XCONS (tem)->car)->cdr;
len += (XSTRING (str)->size +
XSTRING (val)->size +
2);
}
e = env = (unsigned char **) xmalloc (env_len + len);
s = (unsigned char *) env + env_len;
for (tem = Venvironment_alist; !NULL (tem); tem = XCONS (tem)->cdr)
{
str = XCONS (XCONS (tem)->car)->car;
val = XCONS (XCONS (tem)->car)->cdr;
*e++ = s;
len = XSTRING (str)->size;
bcopy (XSTRING (str)->data, s, len);
s += len;
*s++ = '=';
len = XSTRING (val)->size;
bcopy (XSTRING (val)->data, s, len);
s += len;
*s++ = '\000';
}
*e = 0;
return env;
}
#endif /* dead code */
DEFUN ("getenv", Fgetenv, Sgetenv, 1, 2, "sEnvironment variable: \np",
"Return the value of environment variable VAR, as a string.\n\
When invoked interactively, print the value in the echo area.\n\
VAR is a string, the name of the variable,\n\
or the symbol t, meaning to return an alist representing the\n\
current environment.")
(str, interactivep)
Lisp_Object str, interactivep;
{
Lisp_Object val;
if (str == Qt) /* If arg is t, return whole environment */
return (Fcopy_alist (Venvironment_alist));
CHECK_STRING (str, 0);
val = Fcdr (Fassoc (str, Venvironment_alist));
if (!NULL (interactivep))
{
if (NULL (val))
message ("%s not defined in environment", XSTRING (str)->data);
else
message ("\"%s\"", XSTRING (val)->data);
}
return val;
}
DEFUN ("setenv", Fsetenv, Ssetenv, 1, 2,
"sEnvironment variable: \nsSet %s to value: ",
"Return the value of environment variable VAR, as a string.\n\
When invoked interactively, print the value in the echo area.\n\
VAR is a string, the name of the variable.")
(str, val)
Lisp_Object str;
Lisp_Object val;
{
Lisp_Object tem;
CHECK_STRING (str, 0);
if (!NULL (val))
CHECK_STRING (val, 0);
set_environment_alist (str, val);
return val;
}
syms_of_environ ()
{
staticpro (&Venvironment_alist);
defsubr (&Ssetenv);
defsubr (&Sgetenv);
}
init_environ ()
{
Venvironment_alist = Qnil;
initialize_environment_alist ();
}
#endif /* MAINTAIN_ENVIRONMENT */