From 17c38d3c4b9e5c24d41c5bd582be268a207df086 Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <hpa@zytor.com>
Date: Fri, 28 Mar 2008 22:11:11 -0700
Subject: [PATCH] gPXE SAN boot module

Trivial COM32 module which accepts a sanboot command and passes it on
to gPXE.
---
 com32/modules/Makefile  |   3 +-
 com32/modules/sanboot.c | 140 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 142 insertions(+), 1 deletion(-)
 create mode 100644 com32/modules/sanboot.c

diff --git a/com32/modules/Makefile b/com32/modules/Makefile
index 8a127e6..8a8827e 100644
--- a/com32/modules/Makefile
+++ b/com32/modules/Makefile
@@ -52,7 +52,8 @@ INCDIR   = /usr/include
 COM32DIR = $(AUXDIR)/com32
 
 MODULES	  = chain.c32 ethersel.c32 mboot.c32 dmitest.c32 cpuidtest.c32 \
-	    pcitest.c32 elf.c32 linux.c32 reboot.c32 pmload.c32 meminfo.c32
+	    pcitest.c32 elf.c32 linux.c32 reboot.c32 pmload.c32 meminfo.c32 \
+	    sanboot.c32
 TESTFILES =
 
 all: $(MODULES) $(TESTFILES)
diff --git a/com32/modules/sanboot.c b/com32/modules/sanboot.c
new file mode 100644
index 0000000..b8bfe25
--- /dev/null
+++ b/com32/modules/sanboot.c
@@ -0,0 +1,140 @@
+/* ----------------------------------------------------------------------- *
+ *
+ *   Copyright 2008 H. Peter Anvin - All Rights Reserved
+ *
+ *   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., 51 Franklin St, Fifth Floor,
+ *   Boston MA 02110-1301, USA; either version 2 of the License, or
+ *   (at your option) any later version; incorporated herein by reference.
+ *
+ * ----------------------------------------------------------------------- */
+
+/*
+ * sanboot.c
+ *
+ * Invoke the gPXE "sanboot" command, if available.
+ */
+
+#include <alloca.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <console.h>
+#include <com32.h>
+#include <stdbool.h>
+#include <string.h>
+#include <syslinux/config.h>
+
+struct segoff16 {
+  uint16_t offs, seg;
+};
+
+struct s_PXENV_FILE_CHECK_API {
+  uint16_t Status;
+  uint16_t Size;
+  uint32_t Magic;
+  uint32_t Provider;
+  uint32_t APIMask;
+  uint32_t Flags;
+};
+
+static bool is_gpxe(void)
+{
+  const struct syslinux_version *sv;
+  com32sys_t reg;
+  struct s_PXENV_FILE_CHECK_API *fca;
+
+  sv = syslinux_version();
+  if (sv->filesystem != SYSLINUX_FS_PXELINUX)
+    return false;		/* Not PXELINUX */
+
+  fca = __com32.cs_bounce;
+  memset(fca, 0, sizeof *fca);
+  fca->Size  = sizeof *fca;
+  fca->Magic = 0x91d447b2;
+
+  memset(&reg, 0, sizeof reg);
+  reg.eax.w[0] = 0x0009;
+  reg.ebx.w[0] = 0x00e6;	/* PXENV_FILE_API_CHECK */
+  reg.edi.w[0] = OFFS(fca);
+  reg.es       = SEG(fca);
+
+  __intcall(0x22, &reg, &reg);
+
+  if (reg.eflags.l & EFLAGS_CF)
+    return false;		/* Cannot invoke PXE stack */
+
+  if (reg.eax.w[0] || fca->Status)
+    return false;		/* PXE failure */
+
+  if (fca->Magic != 0xe9c17b20)
+    return false;		/* Incorrect magic */
+
+  if (fca->Size < sizeof *fca)
+    return false;		/* Short return */
+
+  if (!(fca->APIMask & (1 << 5)))
+    return false;		/* No FILE EXEC */
+
+  return true;
+}
+
+struct s_PXENV_FILE_EXEC {
+  uint16_t Status;
+  struct segoff16 Command;
+};
+
+static void sanboot(const char **args)
+{
+  char *q;
+  struct s_PXENV_FILE_EXEC *fx;
+  com32sys_t reg;
+
+  memset(&reg, 0, sizeof reg);
+
+  fx = __com32.cs_bounce;
+  q = (char *)(fx+1);
+
+  fx->Status = 1;
+  fx->Command.offs = OFFS(q);
+  fx->Command.seg = SEG(q);
+
+  q = stpcpy(q, "sanboot");
+
+  while (*args) {
+    *q++ = ' ';
+    q = stpcpy(q, *args);
+    args++;
+  }
+
+  memset(&reg, 0, sizeof reg);
+  reg.eax.w[0] = 0x0009;
+  reg.ebx.w[0] = 0x00e5;	/* PXENV_FILE_EXEC */
+  reg.edi.w[0] = OFFS(fx);
+  reg.es       = SEG(fx);
+
+  __intcall(0x22, &reg, &reg);
+
+  /* This should not return... */
+}
+
+int main(int argc, const char *argv[])
+{
+  openconsole(&dev_null_r, &dev_stdcon_w);
+
+  if (argc < 2) {
+    printf("Usage: sanboot rootpath\n");
+    return 1;
+  }
+
+  if (!is_gpxe()) {
+    printf("sanboot: gPXE API not detected\n");
+    return 1;
+  }
+
+  sanboot(argv+1);
+
+  /* sanboot() should not return... */
+  printf("SAN boot failed.\n");
+  return 1;
+}
-- 
2.7.4