[src/trunk]: src/sys/kern Apply the better patch in the PR.

[christos <christos%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/5a449d7a00c8
branches:  trunk
changeset: 771322:5a449d7a00c8
user:      christos <christos%NetBSD.org@localhost>
date:      Sat Nov 19 17:34:41 2011 +0000

description:
Apply the better patch in the PR.

diffstat:

 sys/kern/cnmagic.c |  77 +++++++++++++++++++++++++++++------------------------
 1 files changed, 42 insertions(+), 35 deletions(-)

diffs (142 lines):

diff -r 51f253c23133 -r 5a449d7a00c8 sys/kern/cnmagic.c
--- a/sys/kern/cnmagic.c        Sat Nov 19 17:30:09 2011 +0000
+++ b/sys/kern/cnmagic.c        Sat Nov 19 17:34:41 2011 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: cnmagic.c,v 1.12 2011/11/19 16:11:24 christos Exp $    */
+/*     $NetBSD: cnmagic.c,v 1.13 2011/11/19 17:34:41 christos Exp $    */
 
 /*
  * Copyright (c) 2000 Eduardo Horvath
@@ -26,7 +26,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: cnmagic.c,v 1.12 2011/11/19 16:11:24 christos Exp $");
+__KERNEL_RCSID(0, "$NetBSD: cnmagic.c,v 1.13 2011/11/19 17:34:41 christos Exp $");
 
 #include <sys/param.h>
 #include <sys/systm.h>
@@ -69,33 +69,24 @@
 
        for (i = 0; i < CNS_LEN; i++) {
                c = *magic++;
-               if (c == '\0')
-                       return EINVAL;
-               n = *magic ? i + 1 : CNS_TERM;
                switch (c) {
-               case '\0':
+               case 0:
                        /* End of string */
                        if (i == 0) {
                                /* empty string? */
-                               cn_magic[0] = 0;
 #ifdef DEBUG
                                printf("cn_set_magic(): empty!\n");
 #endif
-                               return 0;
                        }
-                       do
+                       cn_magic[i] = 0;
+                       while (i--)
                                cn_magic[i] = m[i];
-                       while (i--);
                        return 0;
-
-               case '\'':
+               case 0x27:
                        /* Escape sequence */
                        c = *magic++;
-                       if (c == '\0')
-                               return EINVAL;
-                       n = *magic ? i + 1 : CNS_TERM;
                        switch (c) {
-                       case '\'':
+                       case 0x27:
                                break;
                        case 0x01:
                                /* BREAK */
@@ -103,12 +94,13 @@
                                break;
                        case 0x02:
                                /* NUL */
-                               c = '\0';
+                               c = 0;
                                break;
                        }
-                       /*FALLTHROUGH*/
+                       /* FALLTHROUGH */
                default:
                        /* Transition to the next state. */
+                       n = *magic ? i + 1 : CNS_TERM;
 #ifdef DEBUG
                        if (!cold)
                                aprint_normal("mag %d %x:%x\n", i, c, n);
@@ -127,36 +119,51 @@
 int
 cn_get_magic(char *magic, size_t maglen)
 {
-       size_t i, c;
+       size_t i, n = 0;
 
-       for (i = 0; i < CNS_LEN;) {
-               c = cn_magic[i];
+#define ADD_CHAR(x) \
+do \
+       if (n < maglen) \
+               magic[n++] = (x); \
+       else \
+               goto error; \
+while (/*CONSTCOND*/0)
+
+       for (i = 0; i < CNS_LEN; /* empty */) {
+               unsigned short c = cn_magic[i];
+               i = CNS_MAGIC_NEXT(c);
+               if (i == 0)
+                       goto finish;
+
                /* Translate a character */
                switch (CNS_MAGIC_VAL(c)) {
                case CNC_BREAK:
-                       *magic++ = 0x27;
-                       *magic++ = 0x01;
+                       ADD_CHAR(0x27);
+                       ADD_CHAR(0x01);
                        break;
                case 0:
-                       *magic++ = 0x27;
-                       *magic++ = 0x02;
+                       ADD_CHAR(0x27);
+                       ADD_CHAR(0x02);
                        break;
                case 0x27:
-                       *magic++ = 0x27;
-                       *magic++ = 0x27;
+                       ADD_CHAR(0x27);
+                       ADD_CHAR(0x27);
                        break;
                default:
-                       *magic++ = (c & 0x0ff);
+                       ADD_CHAR(c);
                        break;
                }
                /* Now go to the next state */
-               i = CNS_MAGIC_NEXT(c);
-               if (i == CNS_TERM || i == 0) {
-                       /* Either termination state or empty machine */
-                       *magic++ = 0;
-                       return (0);
-               }
+               if (i == CNS_TERM)
+                       goto finish;
        }
-       return (EINVAL);
+
+error:
+       return EINVAL;
+
+finish:
+       /* Either termination state or empty machine */
+       ADD_CHAR('\0');
+       return 0;
 }