1 files changed, 50 insertions, 0 deletions
diff --git a/contrib/syslinux-4.02/com32/lib/sys/gpxe.c b/contrib/syslinux-4.02/com32/lib/sys/gpxe.c
new file mode 100644
index 0000000..d86da42
--- /dev/null
+++ b/contrib/syslinux-4.02/com32/lib/sys/gpxe.c
@@ -0,0 +1,50 @@
+#include <sys/gpxe.h>
+#include <syslinux/config.h>
+#include <string.h>
+
+bool is_gpxe(void)
+{
+    const struct syslinux_version *sv;
+    com32sys_t reg;
+    struct s_PXENV_FILE_CHECK_API *fca;
+    bool gpxe;
+
+    sv = syslinux_version();
+    if (sv->filesystem != SYSLINUX_FS_PXELINUX)
+        return false;           /* Not PXELINUX */
+
+    fca = lzalloc(sizeof *fca);
+    if (!fca)
+	return false;
+    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);
+
+    gpxe = true;
+
+    if (reg.eflags.l & EFLAGS_CF)
+	gpxe = false;           /* Cannot invoke PXE stack */
+
+    if (reg.eax.w[0] || fca->Status)
+        gpxe = false;           /* PXE failure */
+
+    if (fca->Magic != 0xe9c17b20)
+        gpxe = false;           /* Incorrect magic */
+
+    if (fca->Size < sizeof *fca)
+        gpxe = false;           /* Short return */
+
+    /* XXX: The APIs to test for should be a passed-in option */
+    if (!(fca->APIMask & (1 << 5)))
+	gpxe = false;           /* No FILE EXEC */
+
+    lfree(fca);
+    return gpxe;
+}