/* $Id: pe.c,v 1.2 2021/11/06 17:35:07 khorben Exp $ */
/* Copyright (c) 2007 khorben of Uberwall */
/* 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 version 2 of the License.
 *
 * 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  02111-1307  USA */



#include <stdint.h>
#include <string.h>
#include <time.h>
#include "plugin.h"


/* pe */
/* public */
/* types */
#pragma pack(1)
struct pe_hdr
{
	char sig[4];
	uint16_t machine;
	uint16_t sectioncnt;
	uint32_t timestamp;
	uint32_t symbol;
	uint32_t symbolcnt;
	uint16_t opthdrsize;
	uint16_t flags;
};
#pragma pack()


/* variables */
/* magic */
static unsigned char mz[] = "MZ";
static unsigned char dosmode[] = "This program cannot be run in DOS mode";
static unsigned char win32[] = "This program must be run under Win32";
static unsigned char pe[] = "PE\0\0";

static PluginMagic pe_magic[] =
{
	{ 0,	0,	pe,		sizeof(pe)-1		},
	{ 0,	78,	dosmode,	sizeof(dosmode)-1	},
	{ 0,	80,	win32,		sizeof(win32)-1		},
	{ 0,	0,	mz,		sizeof(mz)-1		},
	{ 0,	0,	NULL,		0			}
};


/* functions */
static int pe_callback(PluginHelper * ph, int signature, FILE * fp);


/* plugin */
Plugin plugin =
{
	PT_EXECUTABLE,
	"PE",
	pe_magic,
	pe_callback
};


/* private */
/* functions */
/* pe_callback */
static int _callback_mz(PluginHelper * ph, char * buf);
static int _callback_pe(PluginHelper * ph, char * buf);

static int pe_callback(PluginHelper * ph, int signature, FILE * fp)
{
	char buf[260];
	(void) signature;

	if(fread(buf, sizeof(char), sizeof(buf), fp) != sizeof(buf))
		return -1;
	if(buf[0] == 'M' && buf[1] == 'Z')
		return _callback_mz(ph, buf);
	if(memcmp(buf, pe, sizeof(pe)-1) != 0)
		return -1;
	return _callback_pe(ph, buf);
}

static int _callback_mz(PluginHelper * ph, char * buf)
{
	uint8_t offset = buf[0x3c];

	if(memcmp(&buf[offset], pe, sizeof(pe)-1) != 0)
	{
		ph->printf(ph, "%s", "no PE header found\n");
		return 0;
	}
	ph->printf(ph, "%s%x\n", "PE header is at 0x", offset);
	return 100;
}

static void _pe_endian(struct pe_hdr * pe);
static int _pe_machine(PluginHelper * ph, uint16_t machine);
static int _pe_timestamp(PluginHelper * ph, time_t timestamp);
static int _pe_flags(PluginHelper * ph, uint16_t flags);
static int _callback_pe(PluginHelper * ph, char * buf)
{
	int score = 0;
	struct pe_hdr * pe = (struct pe_hdr *)buf;

	_pe_endian(pe);
	score += _pe_machine(ph, pe->machine);
	ph->printf(ph, "%s%u%s", ", ", pe->sectioncnt, " sections");
	if(pe->sectioncnt < 96)
		score += 100;
	score += _pe_timestamp(ph, pe->timestamp);
	if(pe->symbol == 0)
		score += 100;
	if(pe->symbolcnt == 0)
		score += 100;
	score += _pe_flags(ph, pe->flags);
	ph->printf(ph, "\n");
	return score / 6;
}

static void _pe_endian(struct pe_hdr * pe)
{
	pe->machine = htol16(pe->machine);
	pe->sectioncnt = htol16(pe->sectioncnt);
	pe->timestamp = htol32(pe->timestamp);
	pe->flags = htol16(pe->flags);
}

static int _pe_machine(PluginHelper * ph, uint16_t machine)
{
	struct
	{
		uint16_t machine;
		char * name;
	} mn[] =
	{
		{ 0x0000,	"any"				},
		{ 0x01d3,	"Matsushita AM33"		},
		{ 0x8664,	"x64"				},
		{ 0x01c0,	"ARM little-endian"		},
		{ 0x0ebc,	"EFI byte code"			},
		{ 0x014c,	"i386"				},
		{ 0x0200,	"Itanium"			},
		{ 0x9041,	"Mitsubishi M32R little-endian"	},
		{ 0x0266,	"MIPS16"			},
		{ 0x0366,	"MIPS with FPU"			},
		{ 0x0466,	"MIPS16 with FPU"		},
		{ 0x01f0,	"PPC little-endian"		},
		{ 0x01f1,	"PPC with FPU"			},
		{ 0x0166,	"MIPS little-endian"		},
		{ 0x01a2,	"Hitachi SH3"			},
		{ 0x01a3,	"Hitachi SH3 DSP"		},
		{ 0x01a6,	"Hitachi SH4"			},
		{ 0x01a8,	"Hitachi SH5"			},
		{ 0x01c2,	"Thumb"				},
		{ 0x0169,	"MIPS little-endian WCE v2"	},
		{ 0x0000,	NULL				}
	};
	size_t i;

	for(i = 0; mn[i].name != NULL && mn[i].machine != machine; i++);
	if(mn[i].name == NULL)
	{
		ph->printf(ph, "%s", "unknown machine");
		return 0;
	}
	ph->printf(ph, "%s%s", "machine ", mn[i].name);
	return 100;
}

static int _pe_timestamp(PluginHelper * ph, time_t timestamp)
{
	struct tm tm;
	char tmp[22] = "";

	if(gmtime_r(&timestamp, &tm) == NULL || strftime(tmp, sizeof(tmp),
				", %d/%m/%Y %H:%M:%S", &tm) == 0)
	{
		ph->printf(ph, "%s", ", unknown date");
		return 0;
	}
	ph->printf(ph, "%s", tmp);
	return timestamp < time(NULL) ? 100 : 0;
}

static int _pe_flags(PluginHelper * ph, uint16_t flags)
{
	int score = 0;
	struct
	{
		uint16_t flag;
		char * name;
		int score;
	} fns[] =
	{
		{ 0x0001,	"not relocatable",	100	},
		{ 0x0002,	"executable",		100	},
		{ 0x0004,	"lines stripped",	50	},
		{ 0x0008,	"symbols stripped",	50	},
		{ 0x0010,	"aggressive",		0	},
		{ 0x0020,	"large addresses",	100	},
		{ 0x0040,	"reserved",		0	},
		{ 0x0080,	"little-endian",	0	},
		{ 0x0100,	"32-bits",		100	},
		{ 0x0200,	"stripped",		100	},
		{ 0x0400,	"cache if removable",	100	},
		{ 0x0800,	"cache if network",	100	},
		{ 0x1000,	"system file",		100	},
		{ 0x2000,	"DLL",			100	},
		{ 0x4000,	"uniprocessor",		100	},
		{ 0x8000,	"big-endian",		0	},
		{ 0x0000,	NULL,			0	}
	};
	size_t i;
	int cnt;
	char * sep = "";

	ph->printf(ph, "%s%04x%s", ", flags 0x", flags, " (");
	for(i = 0, cnt = 0; fns[i].name != NULL; i++)
	{
		if((flags & fns[i].flag) != fns[i].flag)
			continue;
		cnt++;
		ph->printf(ph, "%s%s", sep, fns[i].name);
		score += fns[i].score;
		sep = "|";
	}
	ph->printf(ph, ")");
	return cnt != 0 ? score / cnt : 0;
}