Initial. Don't... just don't ask.

utils/restoretextmode.c

@@ -0,0 +1,90 @@
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <vga.h>
+#include "../src/driver.h"
+#include <errno.h>
+
+
+/*
+ * Note: Observe that when writing the font to a file, the file to write is
+ * opened after vga_init has been called (so that root permissions have been
+ * given up). This means that there is no major security hole lurking here.
+ */
+
+unsigned char regs[MAX_REGS];
+
+int
+main (int argc, char *argv[])
+{
+  vga_init ();
+  if (argc == 1)
+    {
+      printf ("Save/restore textmode registers.\n");
+      printf ("Syntax: restoretextmode option filename\n");
+      printf ("	-r filename	Restore registers from file.\n");
+      printf ("	-w filename	Write registers to file.\n");
+      return 0;
+    }
+  if (argv[1][0] != '-')
+    {
+      printf ("Must specify -r or -w.\n");
+      return 1;
+    }
+  switch (argv[1][1])
+    {
+    case 'r':
+    case 'w':
+      if (argc != 3)
+	{
+	  printf ("Must specify filename.\n");
+	  return 1;
+	}
+      break;
+    default:
+      printf ("Invalid option. Must specify -r or -w.\n");
+      return 1;
+    }
+  if (argv[1][1] == 'r')
+    {
+      FILE *f;
+      f = fopen (argv[2], "rb");
+      if (f == NULL)
+	{
+	error:
+	  perror ("restoretextmode");
+	  return 1;
+	}
+      if (1 != fread (regs, MAX_REGS, 1, f))
+	{
+	  if (errno)
+	    goto error;
+	  puts ("restoretextmode: input file corrupted.");
+	  return 1;
+	}
+      fclose (f);
+    }
+  vga_setmode (G640x350x16);
+  switch (argv[1][1])
+    {
+    case 'r':
+      vga_settextmoderegs (regs);
+      break;
+    case 'w':
+      vga_gettextmoderegs (regs);
+      break;
+    }
+  vga_setmode (TEXT);
+  if (argv[1][1] == 'w')
+    {
+      FILE *f;
+      f = fopen (argv[2], "wb");
+      if (f == NULL)
+	goto error;
+      if (1 != fwrite (regs, MAX_REGS, 1, f))
+	goto error;
+      if (fclose (f))
+	goto error;
+    }
+  return 0;
+}