file/src/file.h

/*
 * Copyright (c) Ian F. Darwin 1986-1995.
 * Software written by Ian F. Darwin and others;
 * maintained 1995-present by Christos Zoulas and others.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice immediately at the beginning of the file, without modification,
 *    this list of conditions, and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
/*
 * file.h - definitions for file(1) program
 * @(#)$File: file.h,v 1.193 2018/05/24 18:09:17 christos Exp $
 */

#ifndef __file_h__
#define __file_h__

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif
#ifdef HAVE_STDINT_H
#ifndef __STDC_LIMIT_MACROS
#define __STDC_LIMIT_MACROS
#endif

#ifdef WIN32
  #ifdef _WIN64
    #define SIZE_T_FORMAT "I64"
  #else
    #define SIZE_T_FORMAT ""
  #endif
  #define INT64_T_FORMAT "I64"
  #define INTMAX_T_FORMAT "I64"
#else
  #define SIZE_T_FORMAT "z"
  #define INT64_T_FORMAT "ll"
  #define INTMAX_T_FORMAT "j"
#endif
#include <stdint.h>
#endif

#include <stdio.h>	/* Include that here, to make sure __P gets defined */
#include <errno.h>
#include <fcntl.h>	/* For open and flags */
#ifdef HAVE_INTTYPES_H
#include <inttypes.h>
#endif
#include <regex.h>
#include <time.h>
#include <sys/types.h>
#ifndef WIN32
#include <sys/param.h>
#endif
/* Do this here and now, because struct stat gets re-defined on solaris */
#include <sys/stat.h>
#include <stdarg.h>

#define ENABLE_CONDITIONALS

#ifndef MAGIC
#define MAGIC "/etc/magic"
#endif

#if defined(__EMX__) || defined (WIN32)
#define PATHSEP	';'
#else
#define PATHSEP	':'
#endif

#define private static

#if HAVE_VISIBILITY && !defined(WIN32)
#define public  __attribute__ ((__visibility__("default")))
#ifndef protected
#define protected __attribute__ ((__visibility__("hidden")))
#endif
#else
#define public
#ifndef protected
#define protected
#endif
#endif

#ifndef __arraycount
#define __arraycount(a) (sizeof(a) / sizeof(a[0]))
#endif

#ifndef __GNUC_PREREQ__
#ifdef __GNUC__
#define	__GNUC_PREREQ__(x, y)						\
	((__GNUC__ == (x) && __GNUC_MINOR__ >= (y)) ||			\
	 (__GNUC__ > (x)))
#else
#define	__GNUC_PREREQ__(x, y)	0
#endif
#endif

#ifndef __GNUC__
#ifndef __attribute__
#define __attribute__(a)
#endif
#endif

#ifndef MIN
#define	MIN(a,b)	(((a) < (b)) ? (a) : (b))
#endif

#ifndef MAX
#define	MAX(a,b)	(((a) > (b)) ? (a) : (b))
#endif

#ifndef FILE_BYTES_MAX
# define FILE_BYTES_MAX (1024 * 1024)	/* how much of the file to look at */
#endif
#define MAXMAGIS 8192		/* max entries in any one magic file
				   or directory */
#define MAXDESC	64		/* max len of text description/MIME type */
#define MAXMIME	80		/* max len of text MIME type */
#define MAXstring 96		/* max len of "string" types */

#define MAGICNO		0xF11E041C
#define VERSIONNO	14
#define FILE_MAGICSIZE	344

#define	FILE_LOAD	0
#define FILE_CHECK	1
#define FILE_COMPILE	2
#define FILE_LIST	3

struct buffer {
	int fd;
	struct stat st;
	const void *fbuf;
	size_t flen;
	off_t eoff;
	void *ebuf;
	size_t elen;
};

union VALUETYPE {
	uint8_t b;
	uint16_t h;
	uint32_t l;
	uint64_t q;
	uint8_t hs[2];	/* 2 bytes of a fixed-endian "short" */
	uint8_t hl[4];	/* 4 bytes of a fixed-endian "long" */
	uint8_t hq[8];	/* 8 bytes of a fixed-endian "quad" */
	char s[MAXstring];	/* the search string or regex pattern */
	unsigned char us[MAXstring];
	float f;
	double d;
};

struct magic {
	/* Word 1 */
	uint16_t cont_level;	/* level of ">" */
	uint8_t flag;
#define INDIR		0x01	/* if '(...)' appears */
#define OFFADD		0x02	/* if '>&' or '>...(&' appears */
#define INDIROFFADD	0x04	/* if '>&(' appears */
#define UNSIGNED	0x08	/* comparison is unsigned */
#define NOSPACE		0x10	/* suppress space character before output */
#define BINTEST		0x20	/* test is for a binary type (set only
				   for top-level tests) */
#define TEXTTEST	0x40	/* for passing to file_softmagic */

	uint8_t factor;

	/* Word 2 */
	uint8_t reln;		/* relation (0=eq, '>'=gt, etc) */
	uint8_t vallen;		/* length of string value, if any */
	uint8_t type;		/* comparison type (FILE_*) */
	uint8_t in_type;	/* type of indirection */
#define 			FILE_INVALID	0
#define 			FILE_BYTE	1
#define				FILE_SHORT	2
#define				FILE_DEFAULT	3
#define				FILE_LONG	4
#define				FILE_STRING	5
#define				FILE_DATE	6
#define				FILE_BESHORT	7
#define				FILE_BELONG	8
#define				FILE_BEDATE	9
#define				FILE_LESHORT	10
#define				FILE_LELONG	11
#define				FILE_LEDATE	12
#define				FILE_PSTRING	13
#define				FILE_LDATE	14
#define				FILE_BELDATE	15
#define				FILE_LELDATE	16
#define				FILE_REGEX	17
#define				FILE_BESTRING16	18
#define				FILE_LESTRING16	19
#define				FILE_SEARCH	20
#define				FILE_MEDATE	21
#define				FILE_MELDATE	22
#define				FILE_MELONG	23
#define				FILE_QUAD	24
#define				FILE_LEQUAD	25
#define				FILE_BEQUAD	26
#define				FILE_QDATE	27
#define				FILE_LEQDATE	28
#define				FILE_BEQDATE	29
#define				FILE_QLDATE	30
#define				FILE_LEQLDATE	31
#define				FILE_BEQLDATE	32
#define				FILE_FLOAT	33
#define				FILE_BEFLOAT	34
#define				FILE_LEFLOAT	35
#define				FILE_DOUBLE	36
#define				FILE_BEDOUBLE	37
#define				FILE_LEDOUBLE	38
#define				FILE_BEID3	39
#define				FILE_LEID3	40
#define				FILE_INDIRECT	41
#define				FILE_QWDATE	42
#define				FILE_LEQWDATE	43
#define				FILE_BEQWDATE	44
#define				FILE_NAME	45
#define				FILE_USE	46
#define				FILE_CLEAR	47
#define				FILE_DER	48
#define				FILE_NAMES_SIZE	49 /* size of array to contain all names */

#define IS_STRING(t) \
	((t) == FILE_STRING || \
	 (t) == FILE_PSTRING || \
	 (t) == FILE_BESTRING16 || \
	 (t) == FILE_LESTRING16 || \
	 (t) == FILE_REGEX || \
	 (t) == FILE_SEARCH || \
	 (t) == FILE_INDIRECT || \
	 (t) == FILE_NAME || \
	 (t) == FILE_USE)

#define FILE_FMT_NONE 0
#define FILE_FMT_NUM  1 /* "cduxXi" */
#define FILE_FMT_STR  2 /* "s" */
#define FILE_FMT_QUAD 3 /* "ll" */
#define FILE_FMT_FLOAT 4 /* "eEfFgG" */
#define FILE_FMT_DOUBLE 5 /* "eEfFgG" */

	/* Word 3 */
	uint8_t in_op;		/* operator for indirection */
	uint8_t mask_op;	/* operator for mask */
#ifdef ENABLE_CONDITIONALS
	uint8_t cond;		/* conditional type */
#else
	uint8_t dummy;
#endif
	uint8_t factor_op;
#define		FILE_FACTOR_OP_PLUS	'+'
#define		FILE_FACTOR_OP_MINUS	'-'
#define		FILE_FACTOR_OP_TIMES	'*'
#define		FILE_FACTOR_OP_DIV	'/'
#define		FILE_FACTOR_OP_NONE	'\0'

#define				FILE_OPS	"&|^+-*/%"
#define				FILE_OPAND	0
#define				FILE_OPOR	1
#define				FILE_OPXOR	2
#define				FILE_OPADD	3
#define				FILE_OPMINUS	4
#define				FILE_OPMULTIPLY	5
#define				FILE_OPDIVIDE	6
#define				FILE_OPMODULO	7
#define				FILE_OPS_MASK	0x07 /* mask for above ops */
#define				FILE_UNUSED_1	0x08
#define				FILE_UNUSED_2	0x10
#define				FILE_OPSIGNED	0x20
#define				FILE_OPINVERSE	0x40
#define				FILE_OPINDIRECT	0x80

#ifdef ENABLE_CONDITIONALS
#define				COND_NONE	0
#define				COND_IF		1
#define				COND_ELIF	2
#define				COND_ELSE	3
#endif /* ENABLE_CONDITIONALS */

	/* Word 4 */
	int32_t offset;		/* offset to magic number */
	/* Word 5 */
	int32_t in_offset;	/* offset from indirection */
	/* Word 6 */
	uint32_t lineno;	/* line number in magic file */
	/* Word 7,8 */
	union {
		uint64_t _mask;	/* for use with numeric and date types */
		struct {
			uint32_t _count;	/* repeat/line count */
			uint32_t _flags;	/* modifier flags */
		} _s;		/* for use with string types */
	} _u;
#define num_mask _u._mask
#define str_range _u._s._count
#define str_flags _u._s._flags
	/* Words 9-24 */
	union VALUETYPE value;	/* either number or string */
	/* Words 25-40 */
	char desc[MAXDESC];	/* description */
	/* Words 41-60 */
	char mimetype[MAXMIME]; /* MIME type */
	/* Words 61-62 */
	char apple[8];		/* APPLE CREATOR/TYPE */
	/* Words 63-78 */
	char ext[64];		/* Popular extensions */
};

#define BIT(A)   (1 << (A))
#define STRING_COMPACT_WHITESPACE		BIT(0)
#define STRING_COMPACT_OPTIONAL_WHITESPACE	BIT(1)
#define STRING_IGNORE_LOWERCASE			BIT(2)
#define STRING_IGNORE_UPPERCASE			BIT(3)
#define REGEX_OFFSET_START			BIT(4)
#define STRING_TEXTTEST				BIT(5)
#define STRING_BINTEST				BIT(6)
#define PSTRING_1_BE				BIT(7)
#define PSTRING_1_LE				BIT(7)
#define PSTRING_2_BE				BIT(8)
#define PSTRING_2_LE				BIT(9)
#define PSTRING_4_BE				BIT(10)
#define PSTRING_4_LE				BIT(11)
#define REGEX_LINE_COUNT			BIT(11)
#define PSTRING_LEN	\
    (PSTRING_1_BE|PSTRING_2_LE|PSTRING_2_BE|PSTRING_4_LE|PSTRING_4_BE)
#define PSTRING_LENGTH_INCLUDES_ITSELF		BIT(12)
#define	STRING_TRIM				BIT(13)
#define CHAR_COMPACT_WHITESPACE			'W'
#define CHAR_COMPACT_OPTIONAL_WHITESPACE	'w'
#define CHAR_IGNORE_LOWERCASE			'c'
#define CHAR_IGNORE_UPPERCASE			'C'
#define CHAR_REGEX_OFFSET_START			's'
#define CHAR_TEXTTEST				't'
#define	CHAR_TRIM				'T'
#define CHAR_BINTEST				'b'
#define CHAR_PSTRING_1_BE			'B'
#define CHAR_PSTRING_1_LE			'B'
#define CHAR_PSTRING_2_BE			'H'
#define CHAR_PSTRING_2_LE			'h'
#define CHAR_PSTRING_4_BE			'L'
#define CHAR_PSTRING_4_LE			'l'
#define CHAR_PSTRING_LENGTH_INCLUDES_ITSELF     'J'
#define STRING_IGNORE_CASE		(STRING_IGNORE_LOWERCASE|STRING_IGNORE_UPPERCASE)
#define STRING_DEFAULT_RANGE		100

#define	INDIRECT_RELATIVE			BIT(0)
#define	CHAR_INDIRECT_RELATIVE			'r'

/* list of magic entries */
struct mlist {
	struct magic *magic;		/* array of magic entries */
	uint32_t nmagic;		/* number of entries in array */
	void *map;			/* internal resources used by entry */
	struct mlist *next, *prev;
};

#ifdef __cplusplus
#define CAST(T, b)	static_cast<T>(b)
#define RCAST(T, b)	reinterpret_cast<T>(b)
#define CCAST(T, b)	const_cast<T>(b)
#else
#define CAST(T, b)	((T)(b))
#define RCAST(T, b)	((T)(b))
#define CCAST(T, b)	((T)(uintptr_t)(b))
#endif

struct level_info {
	int32_t off;
	int got_match;
#ifdef ENABLE_CONDITIONALS
	int last_match;
	int last_cond;	/* used for error checking by parse() */
#endif
};

#define MAGIC_SETS	2

struct magic_set {
	struct mlist *mlist[MAGIC_SETS];	/* list of regular entries */
	struct cont {
		size_t len;
		struct level_info *li;
	} c;
	struct out {
		char *buf;		/* Accumulation buffer */
		char *pbuf;		/* Printable buffer */
	} o;
	uint32_t offset;		/* a copy of m->offset while we */
					/* are working on the magic entry */
	uint32_t eoffset;		/* offset from end of file */
	int error;
	int flags;			/* Control magic tests. */
	int event_flags;		/* Note things that happened. */
#define 		EVENT_HAD_ERR		0x01
	const char *file;
	size_t line;			/* current magic line number */
	mode_t mode;			/* copy of current stat mode */

	/* data for searches */
	struct {
		const char *s;		/* start of search in original source */
		size_t s_len;		/* length of search region */
		size_t offset;		/* starting offset in source: XXX - should this be off_t? */
		size_t rm_len;		/* match length */
	} search;

	/* FIXME: Make the string dynamically allocated so that e.g.
	   strings matched in files can be longer than MAXstring */
	union VALUETYPE ms_value;	/* either number or string */
	uint16_t indir_max;
	uint16_t name_max;
	uint16_t elf_shnum_max;
	uint16_t elf_phnum_max;
	uint16_t elf_notes_max;
	uint16_t regex_max;
	size_t bytes_max;		/* number of bytes to read from file */
#define	FILE_INDIR_MAX			50
#define	FILE_NAME_MAX			30
#define	FILE_ELF_SHNUM_MAX		32768
#define	FILE_ELF_PHNUM_MAX		2048
#define	FILE_ELF_NOTES_MAX		256
#define	FILE_REGEX_MAX			8192
};

/* Type for Unicode characters */
typedef unsigned long unichar;

struct stat;
#define FILE_T_LOCAL	1
#define FILE_T_WINDOWS	2
protected const char *file_fmttime(uint64_t, int, char *);
protected struct magic_set *file_ms_alloc(int);
protected void file_ms_free(struct magic_set *);
protected int file_buffer(struct magic_set *, int, const char *, const void *,
    size_t);
protected int file_fsmagic(struct magic_set *, const char *, struct stat *);
protected int file_pipe2file(struct magic_set *, int, const void *, size_t);
protected int file_vprintf(struct magic_set *, const char *, va_list)
    __attribute__((__format__(__printf__, 2, 0)));
protected size_t file_printedlen(const struct magic_set *);
protected int file_replace(struct magic_set *, const char *, const char *);
protected int file_printf(struct magic_set *, const char *, ...)
    __attribute__((__format__(__printf__, 2, 3)));
protected int file_reset(struct magic_set *, int);
protected int file_tryelf(struct magic_set *, const struct buffer *);
protected int file_trycdf(struct magic_set *, const struct buffer *);
#if HAVE_FORK
protected int file_zmagic(struct magic_set *, const struct buffer *,
    const char *);
#endif
protected int file_ascmagic(struct magic_set *, const struct buffer *,
    int);
protected int file_ascmagic_with_encoding(struct magic_set *,
    const struct buffer *, unichar *, size_t, const char *, const char *, int);
protected int file_encoding(struct magic_set *, const struct buffer *,
    unichar **, size_t *, const char **, const char **, const char **);
protected int file_is_tar(struct magic_set *, const struct buffer *);
protected int file_softmagic(struct magic_set *, const struct buffer *,
    uint16_t *, uint16_t *, int, int);
protected int file_apprentice(struct magic_set *, const char *, int);
protected int buffer_apprentice(struct magic_set *, struct magic **,
    size_t *, size_t);
protected int file_magicfind(struct magic_set *, const char *, struct mlist *);
protected uint64_t file_signextend(struct magic_set *, struct magic *,
    uint64_t);
protected void file_badread(struct magic_set *);
protected void file_badseek(struct magic_set *);
protected void file_oomem(struct magic_set *, size_t);
protected void file_error(struct magic_set *, int, const char *, ...)
    __attribute__((__format__(__printf__, 3, 4)));
protected void file_magerror(struct magic_set *, const char *, ...)
    __attribute__((__format__(__printf__, 2, 3)));
protected void file_magwarn(struct magic_set *, const char *, ...)
    __attribute__((__format__(__printf__, 2, 3)));
protected void file_mdump(struct magic *);
protected void file_showstr(FILE *, const char *, size_t);
protected size_t file_mbswidth(const char *);
protected const char *file_getbuffer(struct magic_set *);
protected ssize_t sread(int, void *, size_t, int);
protected int file_check_mem(struct magic_set *, unsigned int);
protected int file_looks_utf8(const unsigned char *, size_t, unichar *,
    size_t *);
protected size_t file_pstring_length_size(const struct magic *);
protected size_t file_pstring_get_length(const struct magic *, const char *);
protected char * file_printable(char *, size_t, const char *);
#ifdef __EMX__
protected int file_os2_apptype(struct magic_set *, const char *, const void *,
    size_t);
#endif /* __EMX__ */

protected void buffer_init(struct buffer *, int, const void *, size_t);
protected void buffer_fini(struct buffer *);
protected int buffer_fill(const struct buffer *);

#if defined(HAVE_LOCALE_H)
#include <locale.h>
#endif
#if defined(HAVE_XLOCALE_H)
#include <xlocale.h>
#endif

typedef struct {
	const char *pat;
#if defined(HAVE_NEWLOCALE) && defined(HAVE_USELOCALE) && defined(HAVE_FREELOCALE)
#define USE_C_LOCALE
	locale_t old_lc_ctype;
	locale_t c_lc_ctype;
#else
	char *old_lc_ctype;
#endif
	int rc;
	regex_t rx;
} file_regex_t;

protected int file_regcomp(file_regex_t *, const char *, int);
protected int file_regexec(file_regex_t *, const char *, size_t, regmatch_t *,
    int);
protected void file_regfree(file_regex_t *);
protected void file_regerror(file_regex_t *, int, struct magic_set *);

typedef struct {
	char *buf;
	uint32_t offset;
} file_pushbuf_t;

protected file_pushbuf_t *file_push_buffer(struct magic_set *);
protected char  *file_pop_buffer(struct magic_set *, file_pushbuf_t *);

#ifndef COMPILE_ONLY
extern const char *file_names[];
extern const size_t file_nnames;
#endif

#ifndef HAVE_STRERROR
extern int sys_nerr;
extern char *sys_errlist[];
#define strerror(e) \
	(((e) >= 0 && (e) < sys_nerr) ? sys_errlist[(e)] : "Unknown error")
#endif

#ifndef HAVE_STRTOUL
#define strtoul(a, b, c)	strtol(a, b, c)
#endif

#ifndef HAVE_PREAD
ssize_t pread(int, void *, size_t, off_t);
#endif
#ifndef HAVE_VASPRINTF
int vasprintf(char **, const char *, va_list);
#endif
#ifndef HAVE_ASPRINTF
int asprintf(char **, const char *, ...);
#endif
#ifndef HAVE_DPRINTF
int dprintf(int, const char *, ...);
#endif

#ifndef HAVE_STRLCPY
size_t strlcpy(char *, const char *, size_t);
#endif
#ifndef HAVE_STRLCAT
size_t strlcat(char *, const char *, size_t);
#endif
#ifndef HAVE_STRCASESTR
char *strcasestr(const char *, const char *);
#endif
#ifndef HAVE_GETLINE
ssize_t getline(char **, size_t *, FILE *);
ssize_t getdelim(char **, size_t *, int, FILE *);
#endif
#ifndef HAVE_CTIME_R
char   *ctime_r(const time_t *, char *);
#endif
#ifndef HAVE_ASCTIME_R
char   *asctime_r(const struct tm *, char *);
#endif
#ifndef HAVE_GMTIME_R
struct tm *gmtime_r(const time_t *, struct tm *);
#endif
#ifndef HAVE_LOCALTIME_R
struct tm *localtime_r(const time_t *, struct tm *);
#endif
#ifndef HAVE_FMTCHECK
const char *fmtcheck(const char *, const char *) 
     __attribute__((__format_arg__(2)));
#endif

#ifdef HAVE_LIBSECCOMP
// basic filter 
// this mode should not interfere with normal operations
// only some dangerous syscalls are blacklisted
int enable_sandbox_basic(void);

// enhanced filter 
// this mode allows only the necessary syscalls used during normal operation
// extensive testing required !!!
int enable_sandbox_full(void);
#endif

protected const char *file_getprogname(void);
protected void file_setprogname(const char *);
protected void file_err(int, const char *, ...)
    __attribute__((__format__(__printf__, 2, 3), __noreturn__));
protected void file_errx(int, const char *, ...)
    __attribute__((__format__(__printf__, 2, 3), __noreturn__));
protected void file_warn(const char *, ...)
    __attribute__((__format__(__printf__, 1, 2)));
protected void file_warnx(const char *, ...)
    __attribute__((__format__(__printf__, 1, 2)));

#if defined(HAVE_MMAP) && defined(HAVE_SYS_MMAN_H) && !defined(QUICK)
#define QUICK
#endif

#ifndef O_BINARY
#define O_BINARY	0
#endif

#ifndef __cplusplus
#if defined(__GNUC__) && (__GNUC__ >= 3)
#define FILE_RCSID(id) \
static const char rcsid[] __attribute__((__used__)) = id;
#else
#define FILE_RCSID(id) \
static const char *rcsid(const char *p) { \
	return rcsid(p = id); \
}
#endif
#else
#define FILE_RCSID(id)
#endif
#ifndef __RCSID
#define __RCSID(a)
#endif

#endif /* __file_h__ */