core: add a direct 32-bit API

Add a direct 32-bit API to some functions; initially read file only.

Signed-off-by: H. Peter Anvin <hpa@zytor.com>

6 files changed, 61 insertions, 3 deletions

diff --git a/core/com32.inc b/core/com32.inc
index cb172794..810ee036 100644
--- a/core/com32.inc
+++ b/core/com32.inc
@@ -1,7 +1,7 @@
 ;; -----------------------------------------------------------------------
 ;;
 ;;   Copyright 1994-2009 H. Peter Anvin - All Rights Reserved
-;;   Copyright 2009 Intel Corporation; author: H. Peter Anvin
+;;   Copyright 2009-2010 Intel Corporation; author: H. Peter Anvin
 ;;
 ;;   This program is free software; you can redistribute it and/or modify
 ;;   it under the terms of the GNU General Public License as published by
@@ -17,6 +17,8 @@
 ;; Common code for running a COM32 image
 ;;
 
+		extern pm_api_vector
+
 ;
 ; Load a COM32 image.  A COM32 image is the 32-bit analogue to a DOS
 ; .com file.  A COM32 image is loaded at address 0x101000, with %esp
@@ -82,6 +84,7 @@ com32_start:
 .pm:
 		; Set up the calling stack frame
 
+		push dword pm_api_vector
 		push dword [HighMemSize]	; Memory managed by Syslinux
 		push dword core_cfarcall	; Cfarcall entry point
 		push dword core_farcall		; Farcall entry point
@@ -89,7 +92,7 @@ com32_start:
 		push dword core_real_mode	; Bounce buffer address
 		push dword core_intcall		; Intcall entry point
 		push dword command_line		; Command line pointer
-		push dword 7			; Argument count
+		push dword 8			; Argument count
 		sti				; Interrupts OK now
 		call com32_entry		; Run the program...
 		; ... on return, fall through to com32_exit ...
@@ -123,7 +126,7 @@ not_com32r_msg	db ': not a COM32R image', CR, LF, 0
 		global __com32
 		alignz 4
 __com32:
-		dd 7				; Argument count
+		dd 8				; Argument count
 		dd 0				; No command line
 		dd core_intcall			; Intcall entry point
 		dd core_xfer_buf		; Bounce buffer address
@@ -131,3 +134,4 @@ __com32:
 		dd core_farcall			; Farcall entry point
 		dd core_cfarcall		; Cfarcall entry point
 HighMemSize	dd 0				; End of memory pointer (bytes)
+		dd pm_api_vector		; Protected mode functions
diff --git a/core/fs/fs.c b/core/fs/fs.c
index d67a87ca..e0f469ba 100644
--- a/core/fs/fs.c
+++ b/core/fs/fs.c
@@ -137,6 +137,27 @@ void getfssec(com32sys_t *regs)
     regs->ecx.l = bytes_read;
 }
 
+size_t pmapi_read_file(uint16_t *handle, void *buf, size_t sectors)
+{
+    bool have_more;
+    size_t bytes_read;
+    struct file *file;
+
+    file = handle_to_file(*handle);
+    bytes_read = file->fs->fs_ops->getfssec(file, buf, sectors, &have_more);
+
+    /*
+     * If we reach EOF, the filesystem driver will have already closed
+     * the underlying file... this really should be cleaner.
+     */
+    if (!have_more) {
+	_close_file(file);
+	*handle = 0;
+    }
+
+    return bytes_read;
+}
+
 void pm_searchdir(com32sys_t *regs)
 {
     char *name = MK_PTR(regs->ds, regs->edi.w[0]);
diff --git a/core/include/core.h b/core/include/core.h
index c955e730..e6364f87 100644
--- a/core/include/core.h
+++ b/core/include/core.h
@@ -3,6 +3,7 @@
 
 #include <klibc/compiler.h>
 #include <com32.h>
+#include <syslinux/pmapi.h>
 
 extern char core_xfer_buf[65536];
 extern char core_cache_buf[65536];
diff --git a/core/include/fs.h b/core/include/fs.h
index 8a173d9f..1f4ad280 100644
--- a/core/include/fs.h
+++ b/core/include/fs.h
@@ -187,6 +187,7 @@ void mangle_name(char *, const char *);
 char *unmangle_name(char *, const char *);
 int searchdir(const char *name);
 void _close_file(struct file *);
+size_t pmapi_read_file(uint16_t *handle, void *buf, size_t sectors);
 
 /* chdir.c */
 void pm_realpath(com32sys_t *regs);
diff --git a/core/include/pmapi.h b/core/include/pmapi.h
new file mode 100644
index 00000000..57d2e6f7
--- /dev/null
+++ b/core/include/pmapi.h
@@ -0,0 +1,8 @@
+#ifndef PMAPI_H
+#define PMAPI_H
+
+#include <syslinux/pmapi.h>
+
+size_t pmapi_read_file(uint16_t *, void *, size_t);
+
+#endif /* PMAPI_H */
diff --git a/core/pmapi.c b/core/pmapi.c
new file mode 100644
index 00000000..f45a7fc6
--- /dev/null
+++ b/core/pmapi.c
@@ -0,0 +1,23 @@
+/* -----------------------------------------------------------------------
+ *
+ *   Copyright 1994-2009 H. Peter Anvin - All Rights Reserved
+ *   Copyright 2009-2010 Intel Corporation; author: H. Peter Anvin
+ *
+ *   This program is free software; you can redistribute it and/or modify
+ *   it under the terms of the GNU General Public License as published by
+ *   the Free Software Foundation, Inc., 53 Temple Place Ste 330,
+ *   Boston MA 02111-1307, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+#include <inttypes.h>
+#include <com32.h>
+#include <syslinux/pmapi.h>
+#include "core.h"
+#include "fs.h"
+
+const struct com32_pmapi pm_api_vector =
+{
+    .read_file	= pmapi_read_file,
+};