Add support for !:strength modifier to adjust strength of a test.

diff --git a/usr.bin/file/magic-load.c b/usr.bin/file/magic-load.c
index c40cbbe..d45f30b 100644 (file)
--- a/usr.bin/file/magic-load.c
+++ b/usr.bin/file/magic-load.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: magic-load.c,v 1.17 2015/08/11 23:17:17 nicm Exp $ */
+/* $OpenBSD: magic-load.c,v 1.18 2015/10/05 20:05:52 nicm Exp $ */
 
 /*
  * Copyright (c) 2015 Nicholas Marriott <nicm@openbsd.org>
@@ -285,8 +285,10 @@ magic_get_strength(struct magic_line *ml)
        if (ml->type == MAGIC_TYPE_NONE)
                return (0);
 
-       if (ml->test_not || ml->test_operator == 'x')
-               return (1);
+       if (ml->test_not || ml->test_operator == 'x') {
+               n = 1;
+               goto skip;
+       }
 
        n = 2 * MAGIC_STRENGTH_MULTIPLIER;
        switch (ml->type) {
@@ -385,6 +387,22 @@ magic_get_strength(struct magic_line *ml)
                n -= MAGIC_STRENGTH_MULTIPLIER;
                break;
        }
+
+skip:
+       switch (ml->strength_operator) {
+       case '+':
+               n += ml->strength_value;
+               break;
+       case '-':
+               n -= ml->strength_value;
+               break;
+       case '*':
+               n *= ml->strength_value;
+               break;
+       case '/':
+               n /= ml->strength_value;
+               break;
+       }
        return (n <= 0 ? 1 : n);
 }
 
@@ -929,6 +947,41 @@ magic_compare(struct magic_line *ml1, struct magic_line *ml2)
 }
 RB_GENERATE(magic_tree, magic_line, node, magic_compare);
 
+static void
+magic_adjust_strength(struct magic *m, u_int at, struct magic_line *ml,
+    char *line)
+{
+       char    *cp, *s;
+       int64_t  value;
+
+       cp = line + (sizeof "!:strength") - 1;
+       while (isspace((u_char)*cp))
+               cp++;
+       s = cp;
+
+       cp = strchr(s, '#');
+       if (cp != NULL)
+               *cp = '\0';
+       cp = s;
+
+       if (strchr("+-*/", *s) == NULL) {
+               magic_warnm(m, at, "invalid strength operator: %s", s);
+               return;
+       }
+       ml->strength_operator = *cp++;
+
+       while (isspace((u_char)*cp))
+               cp++;
+       cp = magic_strtoll(cp, &value);
+       while (cp != NULL && isspace((u_char)*cp))
+               cp++;
+       if (cp == NULL || *cp != '\0' || value < 0 || value > 255) {
+               magic_warnm(m, at, "invalid strength value: %s", s);
+               return;
+       }
+       ml->strength_value = value;
+}
+
 static void
 magic_set_mimetype(struct magic *m, u_int at, struct magic_line *ml, char *line)
 {
@@ -1005,6 +1058,10 @@ magic_load(FILE *f, const char *path, int warnings)
                        magic_set_mimetype(m, at, ml, line);
                        continue;
                }
+               if (strncmp (line, "!:strength", 10) == 0) {
+                       magic_adjust_strength(m, at, ml, line);
+                       continue;
+               }
                if (strncmp (line, "!:", 2) == 0) {
                        for (i = 0; i < 64 && line[i] != '\0'; i++) {
                                if (isspace((u_char)line[i]))

diff --git a/usr.bin/file/magic.h b/usr.bin/file/magic.h
index 106e90a..e1c9fc1 100644 (file)
--- a/usr.bin/file/magic.h
+++ b/usr.bin/file/magic.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: magic.h,v 1.10 2015/10/05 19:50:38 nicm Exp $ */
+/* $OpenBSD: magic.h,v 1.11 2015/10/05 20:05:52 nicm Exp $ */
 
 /*
  * Copyright (c) 2015 Nicholas Marriott <nicm@openbsd.org>
@@ -106,6 +106,9 @@ struct magic_line {
        u_int                    strength;
        struct magic_line       *parent;
 
+       char                     strength_operator;
+       u_int                    strength_value;
+
        int                      text;
 
        int64_t                  offset;