/*-
 * Copyright (c) 2015
 *	KO Myung-Hun <komh@chollian.net>
 *
 * Provided that these terms and disclaimer and all copyright notices
 * are retained or reproduced in an accompanying document, permission
 * is granted to deal in this work without restriction, including un-
 * limited rights to use, publicly perform, distribute, sell, modify,
 * merge, give away, or sublicence.
 *
 * This work is provided "AS IS" and WITHOUT WARRANTY of any kind, to
 * the utmost extent permitted by applicable law, neither express nor
 * implied; without malicious intent or gross negligence. In no event
 * may a licensor, author or contributor be held liable for indirect,
 * direct, other damage, loss, or other issues arising in any way out
 * of dealing in the work, even if advised of the possibility of such
 * damage or existence of a defect, except proven that it results out
 * of said person's immediate fault when using the work as intended.
 */

#include "sh.h"

static char *remove_trailing_dots(char *);
static int access_stat_ex(int (*)(), const char *, void *);
static int test_exec_exist(const char *, char *);

/* Remove trailing dots. */
static char *
remove_trailing_dots(char *name)
{
	char *p;

	for (p = name + strlen(name); --p > name && *p == '.'; )
		/* nothing */;

	if (*p != '.' && *p != '/' && *p != '\\' && *p != ':')
		p[1] = '\0';

	return name;
}

#define REMOVE_TRAILING_DOTS(name)	\
	remove_trailing_dots(strcpy(alloca(strlen(name) + 1), name))

/* Alias of stat() */
int _std_stat(const char *, struct stat *);

/* Replacement for stat() of kLIBC which fails if there are trailing dots */
int
stat(const char *name, struct stat *buffer)
{
	return _std_stat(REMOVE_TRAILING_DOTS(name), buffer);
}

/* Alias of access() */
int _std_access(const char *, int);

/* Replacement for access() of kLIBC which fails if there are trailing dots */
int
access(const char *name, int mode)
{
	/*
	 * On OS/2 kLIBC, X_OK is set only for executable files. This prevent
	 * scripts from being executed.
	 */
	if (mode & X_OK)
		mode = (mode & ~X_OK) | R_OK;

	return _std_access(REMOVE_TRAILING_DOTS(name), mode);
}

#define MAX_X_SUFFIX_LEN	4

static const char *x_suffix_list[] =
	{"", ".ksh", ".exe", ".sh", ".cmd", ".com", ".bat", NULL};

/* Call fn() by appending executable extensions. */
static int
access_stat_ex(int (*fn)(), const char *name, void *arg)
{
	char *x_name;
	const char **x_suffix;
	int rc = -1;

	/* Have an extension ? */
	if (_getext(name))
		return fn(name, arg);

	/* Otherwise, try to append executable suffixes */
	x_name = alloc(strlen(name) + MAX_X_SUFFIX_LEN + 1, ATEMP);

	for (x_suffix = x_suffix_list; rc && *x_suffix; x_suffix++) {
		strcpy(x_name, name);
		strcat(x_name, *x_suffix);

		rc = fn(x_name, arg);
	}

	afree(x_name, ATEMP);

	return rc;
}

/* access()/search_access() version */
int
access_ex(int (*fn)(const char *, int), const char *name, int mode)
{
	return access_stat_ex(fn, name, (void *)mode);
}

static int
test_exec_exist(const char *name, char *real_name)
{
	struct stat sb;

	if (stat(name, &sb) < 0 || !S_ISREG(sb.st_mode))
		return -1;

	strcpy(real_name, name);

	return 0;
}

const char *
real_exec_name(const char *name)
{
	char x_name[strlen(name) + MAX_X_SUFFIX_LEN + 1];
	const char *real_name = name;

	if (access_stat_ex(test_exec_exist, real_name, x_name) != -1)
		strdupx(real_name, x_name, ATEMP);

	return real_name;
}