Add new bios_string() which will hunt for a string inside a given range

of the BIOS.  This can be used for finding arbitrary magic in the BIOS
in order to recognize particular platforms.

2 files changed, 23 insertions, 0 deletions

diff --git a/sys/amd64/amd64/bios.c b/sys/amd64/amd64/bios.c
index 98c39ba..65f79da 100644
--- a/sys/amd64/amd64/bios.c
+++ b/sys/amd64/amd64/bios.c
@@ -474,6 +474,21 @@ bios16(struct bios_args *args, char *fmt, ...)
     return (i);
 }
 
+const u_char *
+bios_string(u_int from, u_int to, const u_char *string, int len)
+{
+	const char *t, *te;
+
+	if (len == 0)
+		len = strlen(string);
+	t = (const char *)(KERNBASE + from);
+	te = (const char *)(KERNBASE + to);
+	for (; t <= te; t++)
+		if (!memcmp(string, t, len))
+			return (t);
+	return (NULL);
+}
+
 #ifdef DEV_ISA
 /*
  * PnP BIOS interface; enumerate devices only known to the system
diff --git a/sys/amd64/include/pc/bios.h b/sys/amd64/include/pc/bios.h
index fe1f703..32b6a52 100644
--- a/sys/amd64/include/pc/bios.h
+++ b/sys/amd64/include/pc/bios.h
@@ -27,6 +27,9 @@
  * $FreeBSD$
  */
 
+#ifndef _MACHINE_PC_BIOS_H_
+#define _MACHINE_PC_BIOS_H_
+
 /* 
  * Signature structure for the BIOS32 Service Directory header 
  */
@@ -278,3 +281,8 @@ struct bios_smap {
     u_int64_t	length;
     u_int32_t	type;
 } __packed;
+
+const u_char *bios_string(u_int from, u_int to, const u_char *string, int len);
+
+
+#endif /* _MACHINE_PC_BIOS_H_ */