[coreboot] r1158 - coreboot-v3/lib

[svn at coreboot.org]

Author: hailfinger
Date: 2009-03-19 13:53:57 +0100 (Thu, 19 Mar 2009)
New Revision: 1158

Modified:
   coreboot-v3/lib/vtxprintf.c
Log:
This patch tries to make printk more readable and reliable.

Base 16 number printing used digits[33] instead of the more readable 'x'
for the "0x" prefix. That means you have to look up an array just to
find out what the code does. Change it.

We already write "<NULL>" if printk gets a NULL pointer as string
argument. Introduce "<near NULL>" for string arguments with addresses
below 0x400. This error happened in the past when dereferencing a struct
member with a string and the struct had the address NULL.

Check if all to-be-printed characters in the string are indeed
printable. The idea is to catch garbage strings from stray pointers and
print "<non-ASCII characters>" instead.
If a string contains characters outside classic ASCII printable stuff,
this will trigger. An example would be characters with diacritic marks
like ?\195?\164?\195?\182?\195?\188?\195?\169?\196?\131?\195?\167?\197?\145?\196?\141.
Then again, I don't see localized versions of coreboot on the horizon.
Maybe for payloads, but not for coreboot itself.

Signed-off-by: Carl-Daniel Hailfinger <c-d.hailfinger.devel.2006 at gmx.net>
Acked-by: Peter Stuge <peter at stuge.se>


Modified: coreboot-v3/lib/vtxprintf.c
===================================================================
--- coreboot-v3/lib/vtxprintf.c	2009-03-19 11:33:16 UTC (rev 1157)
+++ coreboot-v3/lib/vtxprintf.c	2009-03-19 12:53:57 UTC (rev 1158)
@@ -16,6 +16,7 @@
 #define isdigit(c)	((c) >= '0' && (c) <= '9')
 #define is_digit isdigit
 #define isxdigit(c)	(((c) >= '0' && (c) <= '9') || ((c) >= 'a' && (c) <= 'f') || ((c) >= 'A' && (c) <= 'F'))
+#define isprint(c)	((c) == '\n' || ((c) >= ' ' && (c) <= '~'))
 
 static int skip_atoi(const char **s)
 {
@@ -87,7 +88,7 @@
 			tx_byte('0', arg), count++;
 		else if (base==16) {
 			tx_byte('0', arg), count++;
-			tx_byte(digits[33], arg), count++;
+			tx_byte('x', arg), count++;
 		}
 	}
 	if (!(type & LEFT))
@@ -194,9 +195,15 @@
 			s = va_arg(args, char *);
 			if (!s)
 				s = "<NULL>";
+			/* Catch almost-NULL pointers as well */
+			if ((size_t)s < 0x400)
+				s = "<near NULL>";
 
 			len = strnlen(s, precision);
 
+			for (i = 0; i < len; ++i)
+				if (!isprint(*s[i]))
+					s = "<non-ASCII characters>";
 			if (!(flags & LEFT))
 				while (len < field_width--)
 					tx_byte(' ', arg), count++;