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      1 /*	$NetBSD: sh.h,v 1.35 2017/06/30 04:44:46 kamil Exp $	*/
      2 
      3 /*
      4  * Public Domain Bourne/Korn shell
      5  */
      6 
      7 /* $Id: sh.h,v 1.35 2017/06/30 04:44:46 kamil Exp $ */
      8 
      9 #include "config.h"	/* system and option configuration info */
     10 
     11 #define	ARGS(args)	args	/* prototype declaration */
     12 
     13 /* Start of common headers */
     14 
     15 #include <stdio.h>
     16 #include <sys/types.h>
     17 #include <setjmp.h>
     18 #include <stddef.h>
     19 #include <stdlib.h>
     20 #include <unistd.h>
     21 #include <string.h>
     22 #include <stdarg.h>
     23 #include <errno.h>
     24 #include <fcntl.h>
     25 #include <stdint.h>
     26 
     27 #ifndef O_ACCMODE
     28 # define O_ACCMODE	(O_RDONLY|O_WRONLY|O_RDWR)
     29 #endif /* !O_ACCMODE */
     30 
     31 #ifndef F_OK 	/* access() arguments */
     32 # define F_OK 0
     33 # define X_OK 1
     34 # define W_OK 2
     35 # define R_OK 4
     36 #endif /* !F_OK */
     37 
     38 #ifndef SEEK_SET
     39 # ifdef L_SET
     40 #  define SEEK_SET L_SET
     41 #  define SEEK_CUR L_INCR
     42 #  define SEEK_END L_XTND
     43 # else /* L_SET */
     44 #  define SEEK_SET 0
     45 #  define SEEK_CUR 1
     46 #  define SEEK_END 2
     47 # endif /* L_SET */
     48 #endif /* !SEEK_SET */
     49 
     50 #include <limits.h>
     51 
     52 #include <signal.h>
     53 #ifdef	NSIG
     54 # define SIGNALS	NSIG
     55 #else
     56 # ifdef	_MINIX
     57 #  define SIGNALS	(_NSIG+1) /* _NSIG is # of signals used, excluding 0. */
     58 # else
     59 #  ifdef _SIGMAX	/* QNX */
     60 #   define SIGNALS	_SIGMAX
     61 #  else /* _SIGMAX */
     62 #   define SIGNALS	32
     63 #  endif /* _SIGMAX */
     64 # endif	/* _MINIX */
     65 #endif	/* NSIG */
     66 #ifndef SIGCHLD
     67 # define SIGCHLD SIGCLD
     68 #endif
     69 /* struct sigaction.sa_flags is set to KSH_SA_FLAGS.  Used to ensure
     70  * system calls are interrupted
     71  */
     72 #ifdef SA_INTERRUPT
     73 # define KSH_SA_FLAGS	SA_INTERRUPT
     74 #else /* SA_INTERRUPT */
     75 # define KSH_SA_FLAGS	0
     76 #endif /* SA_INTERRUPT */
     77 
     78 typedef	RETSIGTYPE (*handler_t) ARGS((int));	/* signal handler */
     79 
     80 #ifdef HAVE_PATHS_H
     81 # include <paths.h>
     82 #endif /* HAVE_PATHS_H */
     83 #ifdef _PATH_DEFPATH
     84 # define DEFAULT__PATH _PATH_DEFPATH
     85 #else /* _PATH_DEFPATH */
     86 # define DEFAULT__PATH DEFAULT_PATH
     87 #endif /* _PATH_DEFPATH */
     88 
     89 #ifndef HAVE_KILLPG
     90 # define killpg(p, s)	kill(-(p), (s))
     91 #endif /* !HAVE_KILLPG */
     92 
     93 /* this is a hang-over from older versions of the os2 port */
     94 #define ksh_dupbase(fd, base) fcntl(fd, F_DUPFD, base)
     95 
     96 #ifdef HAVE_SIGSETJMP
     97 # define ksh_sigsetjmp(env,sm)	sigsetjmp((env), (sm))
     98 # define ksh_siglongjmp(env,v)	siglongjmp((env), (v))
     99 # define ksh_jmp_buf		sigjmp_buf
    100 #else /* HAVE_SIGSETJMP */
    101 # ifdef HAVE__SETJMP
    102 #  define ksh_sigsetjmp(env,sm)	_setjmp(env)
    103 #  define ksh_siglongjmp(env,v)	_longjmp((env), (v))
    104 # else /* HAVE__SETJMP */
    105 #  define ksh_sigsetjmp(env,sm)	setjmp(env)
    106 #  define ksh_siglongjmp(env,v)	longjmp((env), (v))
    107 # endif /* HAVE__SETJMP */
    108 # define ksh_jmp_buf		jmp_buf
    109 #endif /* HAVE_SIGSETJMP */
    110 
    111 /* end of common headers */
    112 
    113 /* Stop gcc and lint from complaining about possibly uninitialized variables */
    114 #if defined(__GNUC__) || defined(lint)
    115 # define UNINITIALIZED(var)	var = 0
    116 #else
    117 # define UNINITIALIZED(var)	var
    118 #endif /* GNUC || lint */
    119 
    120 /* some useful #defines */
    121 #ifdef EXTERN
    122 # define I__(i) = i
    123 #else
    124 # define I__(i)
    125 # define EXTERN extern
    126 # define EXTERN_DEFINED
    127 #endif
    128 
    129 #ifndef EXECSHELL
    130 /* shell to exec scripts (see also $SHELL initialization in main.c) */
    131 #  define EXECSHELL	"/bin/sh"
    132 #  define EXECSHELL_STR	"EXECSHELL"
    133 #endif
    134 
    135 /* ISABSPATH() means path is fully and completely specified,
    136  * ISROOTEDPATH() means a .. as the first component is a no-op,
    137  * ISRELPATH() means $PWD can be tacked on to get an absolute path.
    138  *
    139  * OS		Path		ISABSPATH	ISROOTEDPATH	ISRELPATH
    140  * unix		/foo		yes		yes		no
    141  * unix		foo		no		no		yes
    142  * unix		../foo		no		no		yes
    143  */
    144 # define PATHSEP        ':'
    145 # define DIRSEP         '/'
    146 # define DIRSEPSTR      "/"
    147 # define ISDIRSEP(c)    ((c) == '/')
    148 # define ISABSPATH(s)	ISDIRSEP((s)[0])
    149 # define ISRELPATH(s)	(!ISABSPATH(s))
    150 # define ISROOTEDPATH(s) ISABSPATH(s)
    151 # define FILECHCONV(c)	c
    152 # define FILECMP(s1, s2) strcmp(s1, s2)
    153 # define FILENCMP(s1, s2, n) strncmp(s1, s2, n)
    154 # define ksh_strchr_dirsep(p)   strchr(p, DIRSEP)
    155 # define ksh_strrchr_dirsep(p)  strrchr(p, DIRSEP)
    156 
    157 #define	NELEM(a) (sizeof(a) / sizeof((a)[0]))
    158 #define	sizeofN(type, n) (sizeof(type) * (n))
    159 #define	BIT(i)	(1<<(i))	/* define bit in flag */
    160 
    161 /* Table flag type - needs > 16 and < 32 bits */
    162 typedef int_least32_t Tflag;
    163 
    164 #define	NUFILE	32		/* Number of user-accessible files */
    165 #define	FDBASE	10		/* First file usable by Shell */
    166 
    167 /* you're not going to run setuid shell scripts, are you? */
    168 #define	eaccess(path, mode)	access(path, mode)
    169 
    170 /* Make MAGIC a char that might be printed to make bugs more obvious, but
    171  * not a char that is used often.  Also, can't use the high bit as it causes
    172  * portability problems (calling strchr(x, 0x80|'x') is error prone).
    173  */
    174 #define	MAGIC		(7)	/* prefix for *?[!{,} during expand */
    175 #define ISMAGIC(c)	((unsigned char)(c) == MAGIC)
    176 #define	NOT		'!'	/* might use ^ (ie, [!...] vs [^..]) */
    177 
    178 #define	LINE	1024		/* input line size */
    179 #define	PATH	1024		/* pathname size (todo: PATH_MAX/pathconf()) */
    180 #define ARRAYMAX 1023		/* max array index */
    181 
    182 EXTERN	const char *kshname;	/* $0 */
    183 EXTERN	pid_t	kshpid;		/* $$, shell pid */
    184 EXTERN	pid_t	procpid;	/* pid of executing process */
    185 EXTERN	uid_t	ksheuid;	/* effective uid of shell */
    186 EXTERN	int	exstat;		/* exit status */
    187 EXTERN	int	subst_exstat;	/* exit status of last $(..)/`..` */
    188 EXTERN	const char *safe_prompt; /* safe prompt if PS1 substitution fails */
    189 
    190 /*
    191  * Area-based allocation built on malloc/free
    192  */
    193 typedef struct Area {
    194 	struct link *freelist;	/* free list */
    195 } Area;
    196 
    197 EXTERN	Area	aperm;		/* permanent object space */
    198 #define	APERM	&aperm
    199 #define	ATEMP	&e->area
    200 
    201 #ifdef KSH_DEBUG
    202 # define kshdebug_init()	kshdebug_init_()
    203 # define kshdebug_printf(a)	kshdebug_printf_ a
    204 # define kshdebug_dump(a)	kshdebug_dump_ a
    205 #else /* KSH_DEBUG */
    206 # define kshdebug_init()
    207 # define kshdebug_printf(a)
    208 # define kshdebug_dump(a)
    209 #endif /* KSH_DEBUG */
    210 
    211 /*
    212  * parsing & execution environment
    213  */
    214 EXTERN	struct env {
    215 	short	type;			/* environment type - see below */
    216 	short	flags;			/* EF_* */
    217 	Area	area;			/* temporary allocation area */
    218 	struct	block *loc;		/* local variables and functions */
    219 	short  *savefd;			/* original redirected fd's */
    220 	struct	env *oenv;		/* link to previous environment */
    221 	ksh_jmp_buf jbuf;		/* long jump back to env creator */
    222 	struct temp *temps;		/* temp files */
    223 } *e;
    224 
    225 /* struct env.type values */
    226 #define	E_NONE	0		/* dummy environment */
    227 #define	E_PARSE	1		/* parsing command # */
    228 #define	E_FUNC	2		/* executing function # */
    229 #define	E_INCL	3		/* including a file via . # */
    230 #define	E_EXEC	4		/* executing command tree */
    231 #define	E_LOOP	5		/* executing for/while # */
    232 #define	E_ERRH	6		/* general error handler # */
    233 /* # indicates env has valid jbuf (see unwind()) */
    234 
    235 /* struct env.flag values */
    236 #define EF_FUNC_PARSE	BIT(0)	/* function being parsed */
    237 #define EF_BRKCONT_PASS	BIT(1)	/* set if E_LOOP must pass break/continue on */
    238 #define EF_FAKE_SIGDIE	BIT(2)	/* hack to get info from unwind to quitenv */
    239 
    240 /* Do breaks/continues stop at env type e? */
    241 #define STOP_BRKCONT(t)	((t) == E_NONE || (t) == E_PARSE \
    242 			 || (t) == E_FUNC || (t) == E_INCL)
    243 /* Do returns stop at env type e? */
    244 #define STOP_RETURN(t)	((t) == E_FUNC || (t) == E_INCL)
    245 
    246 /* values for ksh_siglongjmp(e->jbuf, 0) */
    247 #define LRETURN	1		/* return statement */
    248 #define	LEXIT	2		/* exit statement */
    249 #define LERROR	3		/* errorf() called */
    250 #define LLEAVE	4		/* untrappable exit/error */
    251 #define LINTR	5		/* ^C noticed */
    252 #define	LBREAK	6		/* break statement */
    253 #define	LCONTIN	7		/* continue statement */
    254 #define LSHELL	8		/* return to interactive shell() */
    255 #define LAEXPR	9		/* error in arithmetic expression */
    256 
    257 /* option processing */
    258 #define OF_CMDLINE	0x01	/* command line */
    259 #define OF_SET		0x02	/* set builtin */
    260 #define OF_SPECIAL	0x04	/* a special variable changing */
    261 #define OF_INTERNAL	0x08	/* set internally by shell */
    262 #define OF_ANY		(OF_CMDLINE | OF_SET | OF_SPECIAL | OF_INTERNAL)
    263 
    264 struct option {
    265     const char	*name;	/* long name of option */
    266     char	c;	/* character flag (if any) */
    267     short	flags;	/* OF_* */
    268 };
    269 extern const struct option goptions[];
    270 
    271 /*
    272  * flags (the order of these enums MUST match the order in misc.c(options[]))
    273  */
    274 enum sh_flag {
    275 	FEXPORT = 0,	/* -a: export all */
    276 #ifdef BRACE_EXPAND
    277 	FBRACEEXPAND,	/* enable {} globbing */
    278 #endif
    279 	FBGNICE,	/* bgnice */
    280 	FCOMMAND,	/* -c: (invocation) execute specified command */
    281 #ifdef EMACS
    282 	FEMACS,		/* emacs command editing */
    283 	FEMACSUSEMETA,	/* use 8th bit as meta */
    284 #endif
    285 	FERREXIT,	/* -e: quit on error */
    286 #ifdef EMACS
    287 	FGMACS,		/* gmacs command editing */
    288 #endif
    289 	FIGNOREEOF,	/* eof does not exit */
    290 	FTALKING,	/* -i: interactive */
    291 	FKEYWORD,	/* -k: name=value anywhere */
    292 	FLOGIN,		/* -l: a login shell */
    293 	FMARKDIRS,	/* mark dirs with / in file name completion */
    294 	FMONITOR,	/* -m: job control monitoring */
    295 	FNOCLOBBER,	/* -C: don't overwrite existing files */
    296 	FNOEXEC,	/* -n: don't execute any commands */
    297 	FNOGLOB,	/* -f: don't do file globbing */
    298 	FNOHUP,		/* -H: don't kill running jobs when login shell exits */
    299 	FNOLOG,		/* don't save functions in history (ignored) */
    300 #ifdef	JOBS
    301 	FNOTIFY,	/* -b: asynchronous job completion notification */
    302 #endif
    303 	FNOUNSET,	/* -u: using an unset var is an error */
    304 	FPHYSICAL,	/* -o physical: don't do logical cd's/pwd's */
    305 	FPOSIX,		/* -o posix: be posixly correct */
    306 	FPRIVILEGED,	/* -p: use suid_profile */
    307 	FRESTRICTED,	/* -r: restricted shell */
    308 	FSTDIN,		/* -s: (invocation) parse stdin */
    309 	FTRACKALL,	/* -h: create tracked aliases for all commands */
    310 	FVERBOSE,	/* -v: echo input */
    311 #ifdef VI
    312 	FVI,		/* vi command editing */
    313 	FVIRAW,		/* always read in raw mode (ignored) */
    314 	FVISHOW8,	/* display chars with 8th bit set as is (versus M-) */
    315 	FVITABCOMPLETE,	/* enable tab as file name completion char */
    316 	FVIESCCOMPLETE,	/* enable ESC as file name completion in command mode */
    317 #endif
    318 	FXTRACE,	/* -x: execution trace */
    319 	FTALKING_I,	/* (internal): initial shell was interactive */
    320 	FNFLAGS /* (place holder: how many flags are there) */
    321 };
    322 
    323 #define Flag(f)	(shell_flags[(int) (f)])
    324 
    325 EXTERN	char shell_flags [FNFLAGS];
    326 
    327 EXTERN	char	null [] I__("");	/* null value for variable */
    328 EXTERN	char	space [] I__(" ");
    329 EXTERN	char	newline [] I__("\n");
    330 EXTERN	char	slash [] I__("/");
    331 
    332 enum temp_type {
    333     TT_HEREDOC_EXP,	/* expanded heredoc */
    334     TT_HIST_EDIT	/* temp file used for history editing (fc -e) */
    335 };
    336 typedef enum temp_type Temp_type;
    337 /* temp/heredoc files.  The file is removed when the struct is freed. */
    338 struct temp {
    339 	struct temp	*next;
    340 	struct shf	*shf;
    341 	int		pid;		/* pid of process parsed here-doc */
    342 	Temp_type	type;
    343 	char		*name;
    344 };
    345 
    346 /*
    347  * stdio and our IO routines
    348  */
    349 
    350 #define shl_spare	(&shf_iob[0])	/* for c_read()/c_print() */
    351 #define shl_stdout	(&shf_iob[1])
    352 #define shl_out		(&shf_iob[2])
    353 EXTERN int shl_stdout_ok;
    354 
    355 /*
    356  * trap handlers
    357  */
    358 typedef struct trap {
    359 	int	signal;		/* signal number */
    360 	const char *name;	/* short name */
    361 	const char *mess;	/* descriptive name */
    362 	char   *trap;		/* trap command */
    363 	int	volatile set;	/* trap pending */
    364 	int	flags;		/* TF_* */
    365 	handler_t cursig;	/* current handler (valid if TF_ORIG_* set) */
    366 	handler_t shtrap;	/* shell signal handler */
    367 } Trap;
    368 
    369 /* values for Trap.flags */
    370 #define TF_SHELL_USES	BIT(0)	/* shell uses signal, user can't change */
    371 #define TF_USER_SET	BIT(1)	/* user has (tried to) set trap */
    372 #define TF_ORIG_IGN	BIT(2)	/* original action was SIG_IGN */
    373 #define TF_ORIG_DFL	BIT(3)	/* original action was SIG_DFL */
    374 #define TF_EXEC_IGN	BIT(4)	/* restore SIG_IGN just before exec */
    375 #define TF_EXEC_DFL	BIT(5)	/* restore SIG_DFL just before exec */
    376 #define TF_DFL_INTR	BIT(6)	/* when received, default action is LINTR */
    377 #define TF_TTY_INTR	BIT(7)	/* tty generated signal (see j_waitj) */
    378 #define TF_CHANGED	BIT(8)	/* used by runtrap() to detect trap changes */
    379 #define TF_FATAL	BIT(9)	/* causes termination if not trapped */
    380 
    381 /* values for setsig()/setexecsig() flags argument */
    382 #define SS_RESTORE_MASK	0x3	/* how to restore a signal before an exec() */
    383 #define SS_RESTORE_CURR	0	/* leave current handler in place */
    384 #define SS_RESTORE_ORIG	1	/* restore original handler */
    385 #define SS_RESTORE_DFL	2	/* restore to SIG_DFL */
    386 #define SS_RESTORE_IGN	3	/* restore to SIG_IGN */
    387 #define SS_FORCE	BIT(3)	/* set signal even if original signal ignored */
    388 #define SS_USER		BIT(4)	/* user is doing the set (ie, trap command) */
    389 #define SS_SHTRAP	BIT(5)	/* trap for internal use (CHLD,ALRM,WINCH) */
    390 
    391 #define SIGEXIT_	0	/* for trap EXIT */
    392 #define SIGERR_		SIGNALS	/* for trap ERR */
    393 
    394 EXTERN	int volatile trap;	/* traps pending? */
    395 EXTERN	int volatile intrsig;	/* pending trap interrupts executing command */
    396 EXTERN	int volatile fatal_trap;/* received a fatal signal */
    397 extern	Trap	sigtraps[SIGNALS+1];
    398 
    399 #ifdef KSH
    400 /*
    401  * TMOUT support
    402  */
    403 /* values for ksh_tmout_state */
    404 enum tmout_enum {
    405 		TMOUT_EXECUTING	= 0,	/* executing commands */
    406 		TMOUT_READING,		/* waiting for input */
    407 		TMOUT_LEAVING		/* have timed out */
    408 	};
    409 EXTERN unsigned int ksh_tmout;
    410 EXTERN enum tmout_enum ksh_tmout_state I__(TMOUT_EXECUTING);
    411 #endif /* KSH */
    412 
    413 /* For "You have stopped jobs" message */
    414 EXTERN int really_exit;
    415 
    416 /*
    417  * fast character classes
    418  */
    419 #define	C_ALPHA	 BIT(0)		/* a-z_A-Z */
    420 #define	C_DIGIT	 BIT(1)		/* 0-9 */
    421 #define	C_LEX1	 BIT(2)		/* \0 \t\n|&;<>() */
    422 #define	C_VAR1	 BIT(3)		/* *@#!$-? */
    423 #define	C_IFSWS	 BIT(4)		/* \t \n (IFS white space) */
    424 #define	C_SUBOP1 BIT(5)		/* "=-+?" */
    425 #define	C_SUBOP2 BIT(6)		/* "#%" */
    426 #define	C_IFS	 BIT(7)		/* $IFS */
    427 #define	C_QUOTE	 BIT(8)		/*  \n\t"#$&'()*;<>?[\`| (needing quoting) */
    428 
    429 extern	short ctypes [];
    430 
    431 #define	ctype(c, t)	!!(ctypes[(unsigned char)(c)]&(t))
    432 #define	letter(c)	ctype(c, C_ALPHA)
    433 #define	digit(c)	ctype(c, C_DIGIT)
    434 #define	letnum(c)	ctype(c, C_ALPHA|C_DIGIT)
    435 
    436 EXTERN int ifs0 I__(' ');	/* for "$*" */
    437 
    438 /* Argument parsing for built-in commands and getopts command */
    439 
    440 /* Values for Getopt.flags */
    441 #define GF_ERROR	BIT(0)	/* call errorf() if there is an error */
    442 #define GF_PLUSOPT	BIT(1)	/* allow +c as an option */
    443 #define GF_NONAME	BIT(2)	/* don't print argv[0] in errors */
    444 
    445 /* Values for Getopt.info */
    446 #define GI_MINUS	BIT(0)	/* an option started with -... */
    447 #define GI_PLUS		BIT(1)	/* an option started with +... */
    448 #define GI_MINUSMINUS	BIT(2)	/* arguments were ended with -- */
    449 
    450 typedef struct {
    451 	int		optind;
    452 	int		uoptind;/* what user sees in $OPTIND */
    453 	char		*optarg;
    454 	int		flags;	/* see GF_* */
    455 	int		info;	/* see GI_* */
    456 	unsigned int	p;	/* 0 or index into argv[optind - 1] */
    457 	char		buf[2];	/* for bad option OPTARG value */
    458 } Getopt;
    459 
    460 EXTERN Getopt builtin_opt;	/* for shell builtin commands */
    461 EXTERN Getopt user_opt;		/* parsing state for getopts builtin command */
    462 
    463 #ifdef KSH
    464 /* This for co-processes */
    465 
    466 typedef int_least32_t Coproc_id; /* something that won't (realisticly) wrap */
    467 struct coproc {
    468 	int	read;		/* pipe from co-process's stdout */
    469 	int	readw;		/* other side of read (saved temporarily) */
    470 	int	write;		/* pipe to co-process's stdin */
    471 	Coproc_id id;		/* id of current output pipe */
    472 	int	njobs;		/* number of live jobs using output pipe */
    473 	void    *job;           /* 0 or job of co-process using input pipe */
    474 };
    475 EXTERN struct coproc coproc;
    476 #endif /* KSH */
    477 
    478 /* Used in jobs.c and by coprocess stuff in exec.c */
    479 EXTERN sigset_t		sm_default, sm_sigchld;
    480 
    481 extern char ksh_version[];
    482 
    483 /* name of called builtin function (used by error functions) */
    484 EXTERN char	*builtin_argv0;
    485 EXTERN Tflag	builtin_flag;	/* flags of called builtin (SPEC_BI, etc.) */
    486 
    487 /* current working directory, and size of memory allocated for same */
    488 EXTERN char	*current_wd;
    489 EXTERN int	current_wd_size;
    490 
    491 #ifdef EDIT
    492 /* Minimum required space to work with on a line - if the prompt leaves less
    493  * space than this on a line, the prompt is truncated.
    494  */
    495 # define MIN_EDIT_SPACE	7
    496 /* Minimum allowed value for x_cols: 2 for prompt, 3 for " < " at end of line
    497  */
    498 # define MIN_COLS	(2 + MIN_EDIT_SPACE + 3)
    499 EXTERN	int	x_cols I__(80);	/* tty columns */
    500 #else
    501 # define x_cols 80		/* for pr_menu(exec.c) */
    502 #endif
    503 
    504 /* These to avoid bracket matching problems */
    505 #define OPAREN	'('
    506 #define CPAREN	')'
    507 #define OBRACK	'['
    508 #define CBRACK	']'
    509 #define OBRACE	'{'
    510 #define CBRACE	'}'
    511 
    512 /* Determine the location of the system (common) profile */
    513 #ifndef KSH_SYSTEM_PROFILE
    514 # define KSH_SYSTEM_PROFILE "/etc/profile"
    515 #endif /* KSH_SYSTEM_PROFILE */
    516 
    517 /* Used by v_evaluate() and setstr() to control action when error occurs */
    518 #define KSH_UNWIND_ERROR	0	/* unwind the stack (longjmp) */
    519 #define KSH_RETURN_ERROR	1	/* return 1/0 for success/failure */
    520 
    521 #include "shf.h"
    522 #include "table.h"
    523 #include "tree.h"
    524 #include "expand.h"
    525 #include "lex.h"
    526 #include "proto.h"
    527 
    528 /* be sure not to interfere with anyone else's idea about EXTERN */
    529 #ifdef EXTERN_DEFINED
    530 # undef EXTERN_DEFINED
    531 # undef EXTERN
    532 #endif
    533 #undef I__
    534