/*
 * Copyright (C) 2015 Oracle.
 *
 * 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, see http://www.gnu.org/copyleft/gpl.txt
 */

/*
 * Sometimes people do: "if (err == ENOMEM) {" when the intent was to do:
 * "if (err == -ENOMEM) {"
 */

#include "smatch.h"
#include "smatch_extra.h"

static int my_id;

const char *error_codes[] = {
	"EPERM",
	"ENOENT",
	"ESRCH",
	"EINTR",
	"EIO",
	"ENXIO",
	"E2BIG",
	"ENOEXEC",
	"EBADF",
	"ECHILD",
	"EAGAIN",
	"ENOMEM",
	"EACCES",
	"EFAULT",
	"ENOTBLK",
	"EBUSY",
	"EEXIST",
	"EXDEV",
	"ENODEV",
	"ENOTDIR",
	"EISDIR",
	"EINVAL",
	"ENFILE",
	"EMFILE",
	"ENOTTY",
	"ETXTBSY",
	"EFBIG",
	"ENOSPC",
	"ESPIPE",
	"EROFS",
	"EMLINK",
	"EPIPE",
	"EDOM",
	"ERANGE",
	"EDEADLK",
	"ENAMETOOLONG",
	"ENOLCK",
	"ENOSYS",
	"ENOTEMPTY",
	"ELOOP",
	"EWOULDBLOCK",
	"ENOMSG",
	"EIDRM",
	"ECHRNG",
	"EL2NSYNC",
	"EL3HLT",
	"EL3RST",
	"ELNRNG",
	"EUNATCH",
	"ENOCSI",
	"EL2HLT",
	"EBADE",
	"EBADR",
	"EXFULL",
	"ENOANO",
	"EBADRQC",
	"EBADSLT",
	"EDEADLOCK",
	"EBFONT",
	"ENOSTR",
	"ENODATA",
	"ETIME",
	"ENOSR",
	"ENONET",
	"ENOPKG",
	"EREMOTE",
	"ENOLINK",
	"EADV",
	"ESRMNT",
	"ECOMM",
	"EPROTO",
	"EMULTIHOP",
	"EDOTDOT",
	"EBADMSG",
	"EOVERFLOW",
	"ENOTUNIQ",
	"EBADFD",
	"EREMCHG",
	"ELIBACC",
	"ELIBBAD",
	"ELIBSCN",
	"ELIBMAX",
	"ELIBEXEC",
	"EILSEQ",
	"ERESTART",
	"ESTRPIPE",
	"EUSERS",
	"ENOTSOCK",
	"EDESTADDRREQ",
	"EMSGSIZE",
	"EPROTOTYPE",
	"ENOPROTOOPT",
	"EPROTONOSUPPORT",
	"ESOCKTNOSUPPORT",
	"EOPNOTSUPP",
	"EPFNOSUPPORT",
	"EAFNOSUPPORT",
	"EADDRINUSE",
	"EADDRNOTAVAIL",
	"ENETDOWN",
	"ENETUNREACH",
	"ENETRESET",
	"ECONNABORTED",
	"ECONNRESET",
	"ENOBUFS",
	"EISCONN",
	"ENOTCONN",
	"ESHUTDOWN",
	"ETOOMANYREFS",
	"ETIMEDOUT",
	"ECONNREFUSED",
	"EHOSTDOWN",
	"EHOSTUNREACH",
	"EALREADY",
	"EINPROGRESS",
	"ESTALE",
	"EUCLEAN",
	"ENOTNAM",
	"ENAVAIL",
	"EISNAM",
	"EREMOTEIO",
	"EDQUOT",
	"ENOMEDIUM",
	"EMEDIUMTYPE",
	"ECANCELED",
	"ENOKEY",
	"EKEYEXPIRED",
	"EKEYREVOKED",
	"EKEYREJECTED",
	"EOWNERDEAD",
	"ENOTRECOVERABLE",
	"ERFKILL",
	"EHWPOISON",
	"ERESTARTSYS",
	"ERESTARTNOINTR",
	"ERESTARTNOHAND",
	"ENOIOCTLCMD",
	"ERESTART_RESTARTBLOCK",
	"EPROBE_DEFER",
	"EOPENSTALE",
	"EBADHANDLE",
	"ENOTSYNC",
	"EBADCOOKIE",
	"ENOTSUPP",
	"ETOOSMALL",
	"ESERVERFAULT",
	"EBADTYPE",
	"EJUKEBOX",
	"EIOCBQUEUED",
};

static void warn_on_positive_error(struct expression *expr)
{
	sval_t sval;
	char *name;
	int found = 0;
	int i;

	if (!expr)
		return;

	if (!get_value(expr, &sval))
		return;
	if (sval_is_negative(sval) || sval.value > 4095)
		return;


	name = get_macro_name(expr->pos);
	if (!name)
		return;
	if (name[0] != 'E')
		return;

	for (i = 0; i < ARRAY_SIZE(error_codes); i++) {
		if (strcmp(name, error_codes[i]) == 0) {
			found = 1;
			break;
		}
	}
	if (!found)
		return;

	sm_msg("warn: was negative '-%s' intended?", name);
}

static void match_condition(struct expression *expr)
{
	if (expr->type != EXPR_COMPARE || expr->op != SPECIAL_EQUAL)
		return;

	/* check that the condition is known false */
//	if (!get_implied_value(expr, &sval) || sval.value == 1)
//		return;

	warn_on_positive_error(expr->right);

}

static void match_assign(struct expression *expr)
{
	warn_on_positive_error(expr->right);
}

static void match_return(struct expression *expr)
{
	warn_on_positive_error(expr);
}

void check_positive_error_code(int id)
{
	if (option_project != PROJ_KERNEL)
		return;

	my_id = id;

	add_hook(&match_condition, CONDITION_HOOK);
	add_hook(&match_assign, ASSIGNMENT_HOOK);
	add_hook(&match_return, RETURN_HOOK);
}