/*
 *	fhist - file history and comparison tools
 *	Copyright (C) 1998, 2000, 2002 Peter Miller;
 *	All rights reserved.
 *
 *	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 of the License, 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; if not, write to the Free Software
 *	Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
 *
 * MANIFEST: functions to manipulate errnos
 */

#include <ac/errno.h>
#include <ac/grp.h>
#include <ac/pwd.h>
#include <ac/string.h>
#include <ac/unistd.h>

#include <str.h>
#include <sub/errno.h>
#include <sub/private.h>
#include <trace.h>
#include <wstr_list.h>


/*
 * NAME
 *	sub_errno - the errno substitution
 *
 * SYNOPSIS
 *	wstring_ty *sub_errno(wstring_list_ty *arg);
 *
 * DESCRIPTION
 *	The sub_errno function implements the errno substitution.
 *	The errno substitution is replaced by the value if th errno
 *	variable provided by the system, as mapped through the strerror function.
 *
 *	Requires exactly zero arguments.
 *
 *	The sub_errno_set() function may be used to remember errno,
 *	and thus isolate the error from subsequest system calls.
 *
 * ARGUMENTS
 *	arg	- list of arguments, including the function name as [0]
 *
 * RETURNS
 *	a pointer to a string in dynamic memory;
 *	or NULL on error, setting suberr appropriately.
 */

wstring_ty *
sub_errno(sub_context_ty *scp, wstring_list_ty *arg)
{
    wstring_ty      *result;

    trace(("sub_errno()\n{\n"));
    if (arg->nitems != 1)
    {
	sub_context_error_set(scp, i18n("requires zero arguments"));
	result = 0;
    }
    else
    {
	int		n;

	n = sub_context_errno_get(scp);
	if (n == EPERM || n == EACCES)
	{
	    int             uid;
	    struct passwd   *pw;
	    string_ty       *uidn;
	    int             gid;
	    struct group    *gr;
	    string_ty       *gidn;
	    string_ty       *s;

	    uid = geteuid();
	    pw = getpwuid(uid);
	    if (pw)
		uidn = str_format("user \"%.8s\"", pw->pw_name);
	    else
		uidn = str_format("uid %d", uid);

	    gid = getegid();
	    gr = getgrgid(gid);
	    if (gr)
		gidn = str_format("group \"%.8s\"", gr->gr_name);
	    else
		gidn = str_format("gid %d", gid);

	    s = str_format("%s [%S, %S]", strerror(n), uidn, gidn);
	    str_free(uidn);
	    str_free(gidn);
	    result = str_to_wstr(s);
	    str_free(s);
	}
	else
	    result = wstr_from_c(strerror(n));
    }
    trace(("return %8.8lX;\n", (long)result));
    trace(("}\n"));
    return result;
}