From: Christos Zoulas <christos@zoulas.com>
Date: Fri, 8 Dec 2006 20:31:07 +0000 (+0000)
Subject: - store print the line number of the magic entry for debugging.
X-Git-Tag: FILE4_19~5
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=d4f0d9d0a01809bc259e8d133f666ee7911f980a;p=file

- store print the line number of the magic entry for debugging.
- if the magic entry did not print anything, don't treat it as a match
- change the magic strength algorithm to take into account the relationship op.
---

diff --git a/src/apprentice.c b/src/apprentice.c
index 9f801dbb..0ca23263 100644
--- a/src/apprentice.c
+++ b/src/apprentice.c
@@ -46,7 +46,7 @@
 #endif
 
 #ifndef	lint
-FILE_RCSID("@(#)$Id: apprentice.c,v 1.98 2006/10/31 19:37:17 christos Exp $")
+FILE_RCSID("@(#)$Id: apprentice.c,v 1.99 2006/12/08 20:31:07 christos Exp $")
 #endif	/* lint */
 
 #define	EATAB {while (isascii((unsigned char) *l) && \
@@ -97,7 +97,7 @@ private int hextoint(int);
 private const char *getstr(struct magic_set *, const char *, char *, int,
     int *);
 private int parse(struct magic_set *, struct magic_entry **, uint32_t *,
-    const char *, int);
+    const char *, size_t, int);
 private void eatsize(const char **);
 private int apprentice_1(struct magic_set *, const char *, int, struct mlist *);
 private size_t apprentice_magic_strength(const struct magic *);
@@ -312,33 +312,40 @@ private size_t
 apprentice_magic_strength(const struct magic *m)
 {
 #define MULT 10
+	size_t val = 2 * MULT;	/* baseline strength */
 
 	switch (m->type) {
 	case FILE_BYTE:
-		return 1 * MULT;
+		val += 1 * MULT;
+		break;
 
 	case FILE_SHORT:
 	case FILE_LESHORT:
 	case FILE_BESHORT:
-		return 2 * MULT;
+		val += 2 * MULT;
+		break;
 
 	case FILE_LONG:
 	case FILE_LELONG:
 	case FILE_BELONG:
 	case FILE_MELONG:
-		return 4 * MULT;
+		val += 4 * MULT;
+		break;
 
 	case FILE_PSTRING:
 	case FILE_STRING:
-		return m->vallen * MULT;
+		val += m->vallen * MULT;
+		break;
 
 	case FILE_BESTRING16:
 	case FILE_LESTRING16:
-		return m->vallen * MULT / 2;
+		val += m->vallen * MULT / 2;
+		break;
 
 	case FILE_SEARCH:
 	case FILE_REGEX:
-		return m->vallen;
+		val += m->vallen;
+		break;
 
 	case FILE_DATE:
 	case FILE_LEDATE:
@@ -348,7 +355,8 @@ apprentice_magic_strength(const struct magic *m)
 	case FILE_LELDATE:
 	case FILE_BELDATE:
 	case FILE_MELDATE:
-		return 4 * MULT;
+		val += 4 * MULT;
+		break;
 
 	case FILE_QDATE:
 	case FILE_LEQDATE:
@@ -356,11 +364,40 @@ apprentice_magic_strength(const struct magic *m)
 	case FILE_QLDATE:
 	case FILE_LEQLDATE:
 	case FILE_BEQLDATE:
-		return 8 * MULT;
+		val += 8 * MULT;
+		break;
 
 	default:
-		return 0;
+		val = 0;
+		(void)fprintf(stderr, "Bad type %d\n", m->type);
+		abort();
+	}
+
+	switch (m->reln) {
+	case 'x':	/* matches anything penalize */
+		val = 0;
+		break;
+
+	case '!':
+	case '=':	/* Exact match, prefer */
+		val += MULT;
+		break;
+
+	case '>':
+	case '<':	/* comparison match reduce strength */
+		val -= 2 * MULT;
+		break;
+
+	case '^':
+	case '&':	/* masking bits, we could count them too */
+		val -= MULT;
+		break;
+
+	default:
+		(void)fprintf(stderr, "Bad relation %c\n", m->reln);
+		abort();
 	}
+	return val;
 }
 
 /*  
@@ -396,6 +433,7 @@ apprentice_file(struct magic_set *ms, struct magic **magicp, uint32_t *nmagicp,
 	int errs = 0;
 	struct magic_entry *marray;
 	uint32_t marraycount, i, mentrycount = 0;
+	size_t lineno = 0;
 
 	ms->flags |= MAGIC_CHECK;	/* Enable checks for parsed files */
 
@@ -422,14 +460,18 @@ apprentice_file(struct magic_set *ms, struct magic **magicp, uint32_t *nmagicp,
 	/* read and parse this file */
 	for (ms->line = 1; fgets(line, BUFSIZ, f) != NULL; ms->line++) {
 		size_t len;
-		if (line[0] == '#')	/* comment, do not parse */
-			continue;
 		len = strlen(line);
-		if (len < 2) /* null line, garbage, etc */
+		if (len == 0) /* null line, garbage, etc */
 			continue;
-		if (line[len - 1] == '\n')
+		if (line[len - 1] == '\n') {
+			lineno++;
 			line[len - 1] = '\0'; /* delete newline */
-		if (parse(ms, &marray, &marraycount, line, action) != 0)
+		}
+		if (line[0] == '\0')	/* empty, do not parse */
+			continue;
+		if (line[0] == '#')	/* comment, do not parse */
+			continue;
+		if (parse(ms, &marray, &marraycount, line, lineno, action) != 0)
 			errs++;
 	}
 
@@ -538,7 +580,7 @@ file_signextend(struct magic_set *ms, struct magic *m, uint64_t v)
  */
 private int
 parse(struct magic_set *ms, struct magic_entry **mentryp, uint32_t *nmentryp, 
-    const char *line, int action)
+    const char *line, size_t lineno, int action)
 {
 	size_t i;
 	struct magic_entry *me;
@@ -606,6 +648,7 @@ parse(struct magic_set *ms, struct magic_entry **mentryp, uint32_t *nmentryp,
 		m->cont_level = 0;
 		me->cont_count = 1;
 	}
+	m->lineno = lineno;
 
 	if (m->cont_level != 0 && *l == '&') {
                 ++l;            /* step over */
diff --git a/src/file.h b/src/file.h
index 0e42caae..d223d5c2 100644
--- a/src/file.h
+++ b/src/file.h
@@ -27,7 +27,7 @@
  */
 /*
  * file.h - definitions for file(1) program
- * @(#)$Id: file.h,v 1.81 2006/11/25 17:28:54 christos Exp $
+ * @(#)$Id: file.h,v 1.82 2006/12/08 20:31:07 christos Exp $
  */
 
 #ifndef __file_h__
@@ -225,7 +225,7 @@ struct magic {
 	/* Word 5 */
 	int32_t in_offset;	/* offset from indirection */
 	/* Word 6 */
-	uint32_t dummy4;
+	uint32_t lineno;	/* line number in magic file */
 	/* Word 7,8 */
 	uint64_t mask;	/* mask before comparison with value */
 	/* Words 9-16 */
diff --git a/src/print.c b/src/print.c
index 96046922..28cca18c 100644
--- a/src/print.c
+++ b/src/print.c
@@ -41,7 +41,7 @@
 #include <time.h>
 
 #ifndef lint
-FILE_RCSID("@(#)$Id: print.c,v 1.55 2006/11/01 20:16:43 christos Exp $")
+FILE_RCSID("@(#)$Id: print.c,v 1.56 2006/12/08 20:31:07 christos Exp $")
 #endif  /* lint */
 
 #define SZOF(a)	(sizeof(a) / sizeof(a[0]))
@@ -52,7 +52,7 @@ file_mdump(struct magic *m)
 {
 	private const char optyp[] = { FILE_OPS };
 
-	(void) fputc('[', stderr);
+	(void) fprintf(stderr, "[%zu", m->lineno);
 	(void) fprintf(stderr, ">>>>>>>> %d" + 8 - (m->cont_level & 7),
 		       m->offset);
 
diff --git a/src/softmagic.c b/src/softmagic.c
index 72f07840..5d96261a 100644
--- a/src/softmagic.c
+++ b/src/softmagic.c
@@ -39,7 +39,7 @@
 
 
 #ifndef	lint
-FILE_RCSID("@(#)$Id: softmagic.c,v 1.85 2006/11/25 17:28:54 christos Exp $")
+FILE_RCSID("@(#)$Id: softmagic.c,v 1.86 2006/12/08 20:31:07 christos Exp $")
 #endif	/* lint */
 
 private int match(struct magic_set *, struct magic *, uint32_t,
@@ -68,9 +68,10 @@ protected int
 file_softmagic(struct magic_set *ms, const unsigned char *buf, size_t nbytes)
 {
 	struct mlist *ml;
+	int rv;
 	for (ml = ms->mlist->next; ml != ms->mlist; ml = ml->next)
-		if (match(ms, ml->magic, ml->nmagic, buf, nbytes))
-			return 1;
+		if ((rv = match(ms, ml->magic, ml->nmagic, buf, nbytes)) != 0)
+			return rv;
 
 	return 0;
 }
@@ -113,6 +114,7 @@ match(struct magic_set *ms, struct magic *magic, uint32_t nmagic,
 	int32_t oldoff = 0;
 	int returnval = 0; /* if a match is found it is set to 1*/
 	int firstline = 1; /* a flag to print X\n  X\n- X */
+	int printed_something = 0;
 
 	if (check_mem(ms, cont_level) == -1)
 		return -1;
@@ -123,7 +125,8 @@ match(struct magic_set *ms, struct magic *magic, uint32_t nmagic,
 		int flush = !mget(ms, &p, s, &magic[magindex], nbytes,
 		    cont_level);
 		if (flush) {
-			if (magic[magindex].reln == '!') flush = 0;
+			if (magic[magindex].reln == '!')
+				flush = 0;
 		} else {	
 			switch (magiccheck(ms, &p, &magic[magindex])) {
 			case -1:
@@ -152,6 +155,7 @@ match(struct magic_set *ms, struct magic *magic, uint32_t nmagic,
 		 */
 		if (magic[magindex].desc[0]) {
 			need_separator = 1;
+			printed_something = 1;
 			if (print_sep(ms, firstline) == -1)
 				return -1;
 		}
@@ -197,6 +201,7 @@ match(struct magic_set *ms, struct magic *magic, uint32_t nmagic,
 				 * make sure that we have a separator first.
 				 */
 				if (magic[magindex].desc[0]) {
+					printed_something = 1;
 					if (print_sep(ms, firstline) == -1)
 						return -1;
 				}
@@ -231,8 +236,9 @@ match(struct magic_set *ms, struct magic *magic, uint32_t nmagic,
 			}
 		}
 		firstline = 0;
-		returnval = 1;
-		if ((ms->flags & MAGIC_CONTINUE) == 0) {
+		if (printed_something)
+			returnval = 1;
+		if ((ms->flags & MAGIC_CONTINUE) == 0 && printed_something) {
 			return 1; /* don't keep searching */
 		}			
 	}
@@ -314,7 +320,8 @@ mprint(struct magic_set *ms, union VALUETYPE *p, struct magic *m)
 		case -1:
 			return -1;
 		case 1:
-			if (snprintf(buf, sizeof(buf), "%hu", (unsigned short)v) < 0)
+			if (snprintf(buf, sizeof(buf), "%hu",
+			    (unsigned short)v) < 0)
 				return -1;
 			if (file_printf(ms, m->desc, buf) == -1)
 				return -1;
@@ -1383,14 +1390,18 @@ magiccheck(struct magic_set *ms, union VALUETYPE *p, struct magic *m)
 				ms->offset += range - 1;
 				break;
 			}
-			if (range + slen >= p->search.buflen)
+			if (range + slen >= p->search.buflen) {
+				v = 1;
 				break;
+			}
 			len = slen;
 			a = (unsigned char*)m->value.s;
 			b = (unsigned char*)p->search.buf + range;
 		}
 		free(p->search.buf);
 		p->search.buf = NULL;
+		if (v)
+			return 0;
 		break;
 	}
 	default: