[unix-history] / usr.bin / file / apprentice.c

/*
 * apprentice - make one pass through /etc/magic, learning its secrets.
 *
 * Copyright (c) Ian F. Darwin, 1987.
 * Written by Ian F. Darwin.
 *
 * This software is not subject to any license of the American Telephone
 * and Telegraph Company or of the Regents of the University of California.
 *
 * Permission is granted to anyone to use this software for any purpose on
 * any computer system, and to alter it and redistribute it freely, subject
 * to the following restrictions:
 *
 * 1. The author is not responsible for the consequences of use of this
 *    software, no matter how awful, even if they arise from flaws in it.
 *
 * 2. The origin of this software must not be misrepresented, either by
 *    explicit claim or by omission.  Since few users ever read sources,
 *    credits must appear in the documentation.
 *
 * 3. Altered versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.  Since few users
 *    ever read sources, credits must appear in the documentation.
 *
 * 4. This notice may not be removed or altered.
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include "file.h"

#ifndef	lint
static char *moduleid = 
	"@(#)apprentice.c,v 1.2 1993/06/10 00:38:02 jtc Exp";
#endif	/* lint */

#define	EATAB {while (isascii((unsigned char) *l) && \
		      isspace((unsigned char) *l))  ++l;}


static int getvalue __P((struct magic *, char **));
static int hextoint __P((int));
static char *getstr __P((char *, char *, int, int *));
static int parse    __P((char *, int *, int));

static int maxmagic = 0;

int
apprentice(fn, check)
char *fn;			/* name of magic file */
int check;			/* non-zero? checking-only run. */
{
	FILE *f;
	char line[BUFSIZ+1];
	int errs = 0;

	f = fopen(fn, "r");
	if (f==NULL) {
		(void) fprintf(stderr, "%s: can't read magic file %s\n",
		progname, fn);
		if (check)
			return -1;
		else
			exit(1);
	}

        maxmagic = MAXMAGIS;
	if ((magic = (struct magic *) malloc(sizeof(struct magic) * maxmagic))
	    == NULL) {
		(void) fprintf(stderr, "%s: Out of memory.\n", progname);
		if (check)
			return -1;
		else
			exit(1);
	}

	/* parse it */
	if (check)	/* print silly verbose header for USG compat. */
		(void) printf("cont\toffset\ttype\topcode\tmask\tvalue\tdesc\n");

	for (lineno = 1;fgets(line, BUFSIZ, f) != NULL; lineno++) {
		if (line[0]=='#')	/* comment, do not parse */
			continue;
		if (strlen(line) <= (unsigned)1) /* null line, garbage, etc */
			continue;
		line[strlen(line)-1] = '\0'; /* delete newline */
		if (parse(line, &nmagic, check) != 0)
			++errs;
	}

	(void) fclose(f);
	return errs ? -1 : 0;
}

/*
 * parse one line from magic file, put into magic[index++] if valid
 */
static int
parse(l, ndx, check)
char *l;
int *ndx, check;
{
	int i = 0, nd = *ndx;
	struct magic *m;
	char *t, *s;

	if (nd+1 >= maxmagic){
	    maxmagic += 20;
	    if ((magic = (struct magic *) realloc(magic, 
						  sizeof(struct magic) * 
						  maxmagic)) == NULL) {
		(void) fprintf(stderr, "%s: Out of memory.\n", progname);
		if (check)
			return -1;
		else
			exit(1);
	    }
	}
	m = &magic[*ndx];
	m->flag = 0;
	m->cont_level = 0;

	while (*l == '>') {
		++l;		/* step over */
		m->cont_level++; 
	}

	if (m->cont_level != 0 && *l == '(') {
		++l;		/* step over */
		m->flag |= INDIR;
	}

	/* get offset, then skip over it */
	m->offset = (int) strtol(l,&t,0);
        if (l == t)
		magwarn("offset %s invalid", l);
        l = t;

	if (m->flag & INDIR) {
		m->in.type = LONG;
		m->in.offset = 0;
		/*
		 * read [.lbs][+-]nnnnn)
		 */
		if (*l == '.') {
			switch (*++l) {
			case 'l':
				m->in.type = LONG;
				break;
			case 's':
				m->in.type = SHORT;
				break;
			case 'b':
				m->in.type = BYTE;
				break;
			default:
				magwarn("indirect offset type %c invalid", *l);
				break;
			}
			l++;
		}
		s = l;
		if (*l == '+' || *l == '-') l++;
		if (isdigit((unsigned char)*l)) {
		    m->in.offset = strtol(l, &t, 0);
		    if (*s == '-') m->in.offset = - m->in.offset;
		}
		if (*t++ != ')') 
			magwarn("missing ')' in indirect offset");
		l = t;
	}


	while (isascii((unsigned char)*l) && isdigit((unsigned char)*l))
		++l;
	EATAB;

#define NBYTE		4
#define NSHORT		5
#define NLONG		4
#define NSTRING 	6
#define NDATE		4
#define NBESHORT	7
#define NBELONG		6
#define NBEDATE		6
#define NLESHORT	7
#define NLELONG		6
#define NLEDATE		6

	/* get type, skip it */
	if (strncmp(l, "byte", NBYTE)==0) {
		m->type = BYTE;
		l += NBYTE;
	} else if (strncmp(l, "short", NSHORT)==0) {
		m->type = SHORT;
		l += NSHORT;
	} else if (strncmp(l, "long", NLONG)==0) {
		m->type = LONG;
		l += NLONG;
	} else if (strncmp(l, "string", NSTRING)==0) {
		m->type = STRING;
		l += NSTRING;
	} else if (strncmp(l, "date", NDATE)==0) {
		m->type = DATE;
		l += NDATE;
	} else if (strncmp(l, "beshort", NBESHORT)==0) {
		m->type = BESHORT;
		l += NBESHORT;
	} else if (strncmp(l, "belong", NBELONG)==0) {
		m->type = BELONG;
		l += NBELONG;
	} else if (strncmp(l, "bedate", NBEDATE)==0) {
		m->type = BEDATE;
		l += NBEDATE;
	} else if (strncmp(l, "leshort", NLESHORT)==0) {
		m->type = LESHORT;
		l += NLESHORT;
	} else if (strncmp(l, "lelong", NLELONG)==0) {
		m->type = LELONG;
		l += NLELONG;
	} else if (strncmp(l, "ledate", NLEDATE)==0) {
		m->type = LEDATE;
		l += NLEDATE;
	} else {
		magwarn("type %s invalid", l);
		return -1;
	}
	/* New-style anding: "0 byte&0x80 =0x80 dynamically linked" */
	if (*l == '&') {
		++l;
		m->mask = strtol(l, &l, 0);
	} else
		m->mask = 0L;
	EATAB;
  
	switch (*l) {
	case '>':
	case '<':
	/* Old-style anding: "0 byte &0x80 dynamically linked" */
	case '&':
	case '^':
	case '=':
  		m->reln = *l;
  		++l;
		break;
	case '!':
		if (m->type != STRING) {
			m->reln = *l;
			++l;
			break;
		}
		/* FALL THROUGH */
	default:
		if (*l == 'x' && isascii((unsigned char)l[1]) && 
		    isspace((unsigned char)l[1])) {
			m->reln = *l;
			++l;
			goto GetDesc;	/* Bill The Cat */
		}
  		m->reln = '=';
		break;
	}
  	EATAB;
  
	if (getvalue(m, &l))
		return -1;
	/*
	 * TODO finish this macro and start using it!
	 * #define offsetcheck {if (offset > HOWMANY-1) 
	 *	magwarn("offset too big"); }
	 */

	/*
	 * now get last part - the description
	 */
GetDesc:
	EATAB;
	if (l[0] == '\b') {
		++l;
		m->nospflag = 1;
	} else if ((l[0] == '\\') && (l[1] == 'b')) {
		++l;
		++l;
		m->nospflag = 1;
	} else
		m->nospflag = 0;
	while ((m->desc[i++] = *l++) != '\0' && i<MAXDESC)
		/* NULLBODY */;

	if (check) {
		mdump(m);
	}
	++(*ndx);		/* make room for next */
	return 0;
}

/* 
 * Read a numeric value from a pointer, into the value union of a magic 
 * pointer, according to the magic type.  Update the string pointer to point 
 * just after the number read.  Return 0 for success, non-zero for failure.
 */
static int
getvalue(m, p)
struct magic *m;
char **p;
{
	int slen;

	if (m->type == STRING) {
		*p = getstr(*p, m->value.s, sizeof(m->value.s), &slen);
		m->vallen = slen;
	} else {
		if (m->reln != 'x') {
			switch(m->type) {
			/*
			 * Do not remove the casts below.  They are vital.
			 * When later compared with the data, the sign
			 * extension must have happened.
			 */
			case BYTE:
				m->value.l = (char) strtol(*p,p,0);
				break;
			case SHORT:
			case BESHORT:
			case LESHORT:
				m->value.l = (short) strtol(*p,p,0);
				break;
			case DATE:
			case BEDATE:
			case LEDATE:
			case LONG:
			case BELONG:
			case LELONG:
				m->value.l = (long) strtol(*p,p,0);
				break;
			default:
				magwarn("can't happen: m->type=%d\n", m->type);
				return -1;
			}
		}
	}
	return 0;
}

/*
 * Convert a string containing C character escapes.  Stop at an unescaped
 * space or tab.
 * Copy the converted version to "p", returning its length in *slen.
 * Return updated scan pointer as function result.
 */
static char *
getstr(s, p, plen, slen)
register char	*s;
register char	*p;
int	plen, *slen;
{
	char	*origs = s, *origp = p;
	char	*pmax = p + plen - 1;
	register int	c;
	register int	val;

	while ((c = *s++) != '\0') {
		if (isspace((unsigned char) c))
			break;
		if (p >= pmax) {
			fprintf(stderr, "String too long: %s\n", origs);
			break;
		}
		if(c == '\\') {
			switch(c = *s++) {

			case '\0':
				goto out;

			default:
				*p++ = (char) c;
				break;

			case 'n':
				*p++ = '\n';
				break;

			case 'r':
				*p++ = '\r';
				break;

			case 'b':
				*p++ = '\b';
				break;

			case 't':
				*p++ = '\t';
				break;

			case 'f':
				*p++ = '\f';
				break;

			case 'v':
				*p++ = '\v';
				break;

			/* \ and up to 3 octal digits */
			case '0':
			case '1':
			case '2':
			case '3':
			case '4':
			case '5':
			case '6':
			case '7':
				val = c - '0';
				c = *s++;  /* try for 2 */
				if(c >= '0' && c <= '7') {
					val = (val<<3) | (c - '0');
					c = *s++;  /* try for 3 */
					if(c >= '0' && c <= '7')
						val = (val<<3) | (c-'0');
					else
						--s;
				}
				else
					--s;
				*p++ = (char)val;
				break;

			/* \x and up to 3 hex digits */
			case 'x':
				val = 'x';	/* Default if no digits */
				c = hextoint(*s++);	/* Get next char */
				if (c >= 0) {
					val = c;
					c = hextoint(*s++);
					if (c >= 0) {
						val = (val << 4) + c;
						c = hextoint(*s++);
						if (c >= 0) {
							val = (val << 4) + c;
						} else
							--s;
					} else
						--s;
				} else
					--s;
				*p++ = (char)val;
				break;
			}
		} else
			*p++ = (char)c;
	}
out:
	*p = '\0';
	*slen = p - origp;
	return s;
}


/* Single hex char to int; -1 if not a hex char. */
static int
hextoint(c)
int c;
{
	if (!isascii((unsigned char) c))	return -1;
	if (isdigit((unsigned char) c))		return c - '0';
	if ((c>='a')&&(c<='f'))	return c + 10 - 'a';
	if ((c>='A')&&(c<='F'))	return c + 10 - 'A';
				return -1;
}


/*
 * Print a string containing C character escapes.
 */
void
showstr(s)
const char *s;
{
	register char	c;

	while((c = *s++) != '\0') {
		if(c >= 040 && c <= 0176)	/* TODO isprint && !iscntrl */
			putchar(c);
		else {
			putchar('\\');
			switch (c) {
			
			case '\n':
				putchar('n');
				break;

			case '\r':
				putchar('r');
				break;

			case '\b':
				putchar('b');
				break;

			case '\t':
				putchar('t');
				break;

			case '\f':
				putchar('f');
				break;

			case '\v':
				putchar('v');
				break;

			default:
				printf("%.3o", c & 0377);
				break;
			}
		}
	}
	putchar('\t');
}
Commit	Line	Data
15637ed4 RG	1	/*
	2	* apprentice - make one pass through /etc/magic, learning its secrets.
	3	*
	4	* Copyright (c) Ian F. Darwin, 1987.
	5	* Written by Ian F. Darwin.
	6	*
	7	* This software is not subject to any license of the American Telephone
	8	* and Telegraph Company or of the Regents of the University of California.
	9	*
	10	* Permission is granted to anyone to use this software for any purpose on
	11	* any computer system, and to alter it and redistribute it freely, subject
	12	* to the following restrictions:
	13	*
	14	* 1. The author is not responsible for the consequences of use of this
	15	* software, no matter how awful, even if they arise from flaws in it.
	16	*
	17	* 2. The origin of this software must not be misrepresented, either by
	18	* explicit claim or by omission. Since few users ever read sources,
	19	* credits must appear in the documentation.
	20	*
	21	* 3. Altered versions must be plainly marked as such, and must not be
	22	* misrepresented as being the original software. Since few users
	23	* ever read sources, credits must appear in the documentation.
	24	*
	25	* 4. This notice may not be removed or altered.
	26	*/
	27
	28	#include <stdio.h>
286a6f32 C	29	#include <stdlib.h>
286a6f32 C	30	#include <string.h>
15637ed4 RG	31	#include <ctype.h>
	32	#include "file.h"
	33
	34	#ifndef lint
	35	static char *moduleid =
286a6f32	36	"@(#)apprentice.c,v 1.2 1993/06/10 00:38:02 jtc Exp";
15637ed4 RG	37	#endif /* lint */
15637ed4 RG	38
286a6f32 C	39	#define EATAB {while (isascii((unsigned char) *l) && \
286a6f32 C	40	isspace((unsigned char) *l)) ++l;}
15637ed4	41
15637ed4	42
286a6f32 C	43	static int getvalue __P((struct magic , char *));
	44	static int hextoint __P((int));
	45	static char getstr __P((char , char , int, int ));
	46	static int parse __P((char , int , int));
15637ed4	47
286a6f32	48	static int maxmagic = 0;
15637ed4	49
286a6f32	50	int
15637ed4 RG	51	apprentice(fn, check)
15637ed4 RG	52	char fn; / name of magic file */
286a6f32	53	int check; /* non-zero? checking-only run. */
15637ed4 RG	54	{
15637ed4 RG	55	FILE *f;
286a6f32	56	char line[BUFSIZ+1];
15637ed4 RG	57	int errs = 0;
	58
	59	f = fopen(fn, "r");
	60	if (f==NULL) {
	61	(void) fprintf(stderr, "%s: can't read magic file %s\n",
	62	progname, fn);
	63	if (check)
	64	return -1;
	65	else
	66	exit(1);
	67	}
	68
286a6f32 C	69	maxmagic = MAXMAGIS;
	70	if ((magic = (struct magic ) malloc(sizeof(struct magic) maxmagic))
	71	== NULL) {
	72	(void) fprintf(stderr, "%s: Out of memory.\n", progname);
	73	if (check)
	74	return -1;
	75	else
	76	exit(1);
	77	}
	78
15637ed4 RG	79	/* parse it */
15637ed4 RG	80	if (check) /* print silly verbose header for USG compat. */
286a6f32	81	(void) printf("cont\toffset\ttype\topcode\tmask\tvalue\tdesc\n");
15637ed4	82
286a6f32	83	for (lineno = 1;fgets(line, BUFSIZ, f) != NULL; lineno++) {
15637ed4 RG	84	if (line[0]=='#') /* comment, do not parse */
15637ed4 RG	85	continue;
286a6f32	86	if (strlen(line) <= (unsigned)1) /* null line, garbage, etc */
15637ed4 RG	87	continue;
	88	line[strlen(line)-1] = '\0'; /* delete newline */
	89	if (parse(line, &nmagic, check) != 0)
	90	++errs;
	91	}
	92
	93	(void) fclose(f);
	94	return errs ? -1 : 0;
	95	}
	96
	97	/*
	98	* parse one line from magic file, put into magic[index++] if valid
	99	*/
286a6f32	100	static int
15637ed4 RG	101	parse(l, ndx, check)
	102	char *l;
	103	int *ndx, check;
	104	{
	105	int i = 0, nd = *ndx;
15637ed4	106	struct magic *m;
286a6f32 C	107	char t, s;
	108
	109	if (nd+1 >= maxmagic){
	110	maxmagic += 20;
	111	if ((magic = (struct magic *) realloc(magic,
	112	sizeof(struct magic) *
	113	maxmagic)) == NULL) {
	114	(void) fprintf(stderr, "%s: Out of memory.\n", progname);
	115	if (check)
	116	return -1;
	117	else
	118	exit(1);
	119	}
15637ed4 RG	120	}
15637ed4 RG	121	m = &magic[*ndx];
286a6f32 C	122	m->flag = 0;
286a6f32 C	123	m->cont_level = 0;
15637ed4	124
286a6f32	125	while (*l == '>') {
15637ed4	126	++l; /* step over */
286a6f32 C	127	m->cont_level++;
	128	}
	129
	130	if (m->cont_level != 0 && *l == '(') {
	131	++l; /* step over */
	132	m->flag \|= INDIR;
	133	}
15637ed4 RG	134
15637ed4 RG	135	/* get offset, then skip over it */
286a6f32 C	136	m->offset = (int) strtol(l,&t,0);
	137	if (l == t)
	138	magwarn("offset %s invalid", l);
	139	l = t;
	140
	141	if (m->flag & INDIR) {
	142	m->in.type = LONG;
	143	m->in.offset = 0;
	144	/*
	145	* read [.lbs][+-]nnnnn)
	146	*/
	147	if (*l == '.') {
	148	switch (*++l) {
	149	case 'l':
	150	m->in.type = LONG;
	151	break;
	152	case 's':
	153	m->in.type = SHORT;
	154	break;
	155	case 'b':
	156	m->in.type = BYTE;
	157	break;
	158	default:
	159	magwarn("indirect offset type %c invalid", *l);
	160	break;
	161	}
	162	l++;
	163	}
	164	s = l;
	165	if (l == '+' \|\| l == '-') l++;
	166	if (isdigit((unsigned char)*l)) {
	167	m->in.offset = strtol(l, &t, 0);
	168	if (*s == '-') m->in.offset = - m->in.offset;
	169	}
	170	if (*t++ != ')')
	171	magwarn("missing ')' in indirect offset");
	172	l = t;
	173	}
	174
	175
	176	while (isascii((unsigned char)l) && isdigit((unsigned char)l))
15637ed4 RG	177	++l;
	178	EATAB;
	179
286a6f32 C	180	#define NBYTE 4
	181	#define NSHORT 5
	182	#define NLONG 4
	183	#define NSTRING 6
	184	#define NDATE 4
	185	#define NBESHORT 7
	186	#define NBELONG 6
	187	#define NBEDATE 6
	188	#define NLESHORT 7
	189	#define NLELONG 6
	190	#define NLEDATE 6
	191
15637ed4 RG	192	/* get type, skip it */
	193	if (strncmp(l, "byte", NBYTE)==0) {
	194	m->type = BYTE;
	195	l += NBYTE;
	196	} else if (strncmp(l, "short", NSHORT)==0) {
	197	m->type = SHORT;
	198	l += NSHORT;
	199	} else if (strncmp(l, "long", NLONG)==0) {
	200	m->type = LONG;
	201	l += NLONG;
	202	} else if (strncmp(l, "string", NSTRING)==0) {
	203	m->type = STRING;
	204	l += NSTRING;
286a6f32 C	205	} else if (strncmp(l, "date", NDATE)==0) {
	206	m->type = DATE;
	207	l += NDATE;
	208	} else if (strncmp(l, "beshort", NBESHORT)==0) {
	209	m->type = BESHORT;
	210	l += NBESHORT;
	211	} else if (strncmp(l, "belong", NBELONG)==0) {
	212	m->type = BELONG;
	213	l += NBELONG;
	214	} else if (strncmp(l, "bedate", NBEDATE)==0) {
	215	m->type = BEDATE;
	216	l += NBEDATE;
	217	} else if (strncmp(l, "leshort", NLESHORT)==0) {
	218	m->type = LESHORT;
	219	l += NLESHORT;
	220	} else if (strncmp(l, "lelong", NLELONG)==0) {
	221	m->type = LELONG;
	222	l += NLELONG;
	223	} else if (strncmp(l, "ledate", NLEDATE)==0) {
	224	m->type = LEDATE;
	225	l += NLEDATE;
15637ed4	226	} else {
286a6f32	227	magwarn("type %s invalid", l);
15637ed4 RG	228	return -1;
15637ed4 RG	229	}
286a6f32 C	230	/* New-style anding: "0 byte&0x80 =0x80 dynamically linked" */
286a6f32 C	231	if (*l == '&') {
15637ed4	232	++l;
286a6f32	233	m->mask = strtol(l, &l, 0);
15637ed4	234	} else
286a6f32	235	m->mask = 0L;
15637ed4	236	EATAB;
286a6f32 C	237
	238	switch (*l) {
	239	case '>':
	240	case '<':
	241	/* Old-style anding: "0 byte &0x80 dynamically linked" */
	242	case '&':
	243	case '^':
	244	case '=':
	245	m->reln = *l;
	246	++l;
15637ed4	247	break;
286a6f32 C	248	case '!':
	249	if (m->type != STRING) {
	250	m->reln = *l;
	251	++l;
	252	break;
	253	}
	254	/* FALL THROUGH */
15637ed4	255	default:
286a6f32 C	256	if (*l == 'x' && isascii((unsigned char)l[1]) &&
	257	isspace((unsigned char)l[1])) {
	258	m->reln = *l;
	259	++l;
	260	goto GetDesc; /* Bill The Cat */
	261	}
	262	m->reln = '=';
	263	break;
15637ed4	264	}
286a6f32 C	265	EATAB;
	266
	267	if (getvalue(m, &l))
	268	return -1;
	269	/*
	270	* TODO finish this macro and start using it!
	271	* #define offsetcheck {if (offset > HOWMANY-1)
	272	* magwarn("offset too big"); }
	273	*/
15637ed4 RG	274
	275	/*
	276	* now get last part - the description
	277	*/
286a6f32	278	GetDesc:
15637ed4	279	EATAB;
286a6f32 C	280	if (l[0] == '\b') {
	281	++l;
	282	m->nospflag = 1;
	283	} else if ((l[0] == '\\') && (l[1] == 'b')) {
	284	++l;
	285	++l;
	286	m->nospflag = 1;
	287	} else
	288	m->nospflag = 0;
15637ed4 RG	289	while ((m->desc[i++] = *l++) != '\0' && i<MAXDESC)
	290	/* NULLBODY */;
	291
	292	if (check) {
	293	mdump(m);
	294	}
	295	++(ndx); / make room for next */
	296	return 0;
	297	}
	298
286a6f32 C	299	/*
	300	* Read a numeric value from a pointer, into the value union of a magic
	301	* pointer, according to the magic type. Update the string pointer to point
	302	* just after the number read. Return 0 for success, non-zero for failure.
	303	*/
	304	static int
	305	getvalue(m, p)
	306	struct magic *m;
	307	char **p;
	308	{
	309	int slen;
	310
	311	if (m->type == STRING) {
	312	p = getstr(p, m->value.s, sizeof(m->value.s), &slen);
	313	m->vallen = slen;
	314	} else {
	315	if (m->reln != 'x') {
	316	switch(m->type) {
	317	/*
	318	* Do not remove the casts below. They are vital.
	319	* When later compared with the data, the sign
	320	* extension must have happened.
	321	*/
	322	case BYTE:
	323	m->value.l = (char) strtol(*p,p,0);
	324	break;
	325	case SHORT:
	326	case BESHORT:
	327	case LESHORT:
	328	m->value.l = (short) strtol(*p,p,0);
	329	break;
	330	case DATE:
	331	case BEDATE:
	332	case LEDATE:
	333	case LONG:
	334	case BELONG:
	335	case LELONG:
	336	m->value.l = (long) strtol(*p,p,0);
	337	break;
	338	default:
	339	magwarn("can't happen: m->type=%d\n", m->type);
	340	return -1;
	341	}
	342	}
	343	}
	344	return 0;
	345	}
	346
15637ed4 RG	347	/*
	348	* Convert a string containing C character escapes. Stop at an unescaped
	349	* space or tab.
	350	* Copy the converted version to "p", returning its length in *slen.
	351	* Return updated scan pointer as function result.
	352	*/
286a6f32	353	static char *
15637ed4 RG	354	getstr(s, p, plen, slen)
	355	register char *s;
	356	register char *p;
	357	int plen, *slen;
	358	{
	359	char origs = s, origp = p;
	360	char *pmax = p + plen - 1;
	361	register int c;
	362	register int val;
	363
286a6f32 C	364	while ((c = *s++) != '\0') {
	365	if (isspace((unsigned char) c))
	366	break;
15637ed4 RG	367	if (p >= pmax) {
	368	fprintf(stderr, "String too long: %s\n", origs);
	369	break;
	370	}
	371	if(c == '\\') {
	372	switch(c = *s++) {
	373
	374	case '\0':
	375	goto out;
	376
	377	default:
286a6f32	378	*p++ = (char) c;
15637ed4 RG	379	break;
	380
	381	case 'n':
	382	*p++ = '\n';
	383	break;
	384
	385	case 'r':
	386	*p++ = '\r';
	387	break;
	388
	389	case 'b':
	390	*p++ = '\b';
	391	break;
	392
	393	case 't':
	394	*p++ = '\t';
	395	break;
	396
	397	case 'f':
	398	*p++ = '\f';
	399	break;
	400
	401	case 'v':
	402	*p++ = '\v';
	403	break;
	404
	405	/* \ and up to 3 octal digits */
	406	case '0':
	407	case '1':
	408	case '2':
	409	case '3':
	410	case '4':
	411	case '5':
	412	case '6':
	413	case '7':
	414	val = c - '0';
	415	c = s++; / try for 2 */
	416	if(c >= '0' && c <= '7') {
	417	val = (val<<3) \| (c - '0');
	418	c = s++; / try for 3 */
	419	if(c >= '0' && c <= '7')
	420	val = (val<<3) \| (c-'0');
	421	else
	422	--s;
	423	}
	424	else
	425	--s;
286a6f32	426	*p++ = (char)val;
15637ed4 RG	427	break;
	428
	429	/* \x and up to 3 hex digits */
	430	case 'x':
	431	val = 'x'; /* Default if no digits */
	432	c = hextoint(s++); / Get next char */
	433	if (c >= 0) {
	434	val = c;
	435	c = hextoint(*s++);
	436	if (c >= 0) {
	437	val = (val << 4) + c;
	438	c = hextoint(*s++);
	439	if (c >= 0) {
	440	val = (val << 4) + c;
	441	} else
	442	--s;
	443	} else
	444	--s;
	445	} else
	446	--s;
286a6f32	447	*p++ = (char)val;
15637ed4 RG	448	break;
	449	}
	450	} else
286a6f32	451	*p++ = (char)c;
15637ed4 RG	452	}
	453	out:
	454	*p = '\0';
	455	*slen = p - origp;
286a6f32	456	return s;
15637ed4 RG	457	}
	458
	459
	460	/* Single hex char to int; -1 if not a hex char. */
286a6f32	461	static int
15637ed4	462	hextoint(c)
286a6f32	463	int c;
15637ed4	464	{
286a6f32 C	465	if (!isascii((unsigned char) c)) return -1;
	466	if (isdigit((unsigned char) c)) return c - '0';
	467	if ((c>='a')&&(c<='f')) return c + 10 - 'a';
	468	if ((c>='A')&&(c<='F')) return c + 10 - 'A';
15637ed4 RG	469	return -1;
	470	}
	471
	472
	473	/*
	474	* Print a string containing C character escapes.
	475	*/
	476	void
	477	showstr(s)
286a6f32	478	const char *s;
15637ed4 RG	479	{
	480	register char c;
	481
	482	while((c = *s++) != '\0') {
286a6f32	483	if(c >= 040 && c <= 0176) /* TODO isprint && !iscntrl */
15637ed4 RG	484	putchar(c);
	485	else {
	486	putchar('\\');
	487	switch (c) {
	488
	489	case '\n':
	490	putchar('n');
	491	break;
	492
	493	case '\r':
	494	putchar('r');
	495	break;
	496
	497	case '\b':
	498	putchar('b');
	499	break;
	500
	501	case '\t':
	502	putchar('t');
	503	break;
	504
	505	case '\f':
	506	putchar('f');
	507	break;
	508
	509	case '\v':
	510	putchar('v');
	511	break;
	512
	513	default:
	514	printf("%.3o", c & 0377);
	515	break;
	516	}
	517	}
	518	}
	519	putchar('\t');
	520	}