com32/modules/sanboot.c

   1 /* ----------------------------------------------------------------------- *
   2  *
   3  *   Copyright 2008 H. Peter Anvin - All Rights Reserved
   4  *
   5  *   This program is free software; you can redistribute it and/or modify
   6  *   it under the terms of the GNU General Public License as published by
   7  *   the Free Software Foundation, Inc., 51 Franklin St, Fifth Floor,
   8  *   Boston MA 02110-1301, USA; either version 2 of the License, or
   9  *   (at your option) any later version; incorporated herein by reference.
  10  *
  11  * ----------------------------------------------------------------------- */
  12
  13 /*
  14  * sanboot.c
  15  *
  16  * Invoke the gPXE "sanboot" command, if available.
  17  */
  18
  19 #include <alloca.h>
  20 #include <inttypes.h>
  21 #include <stdio.h>
  22 #include <console.h>
  23 #include <com32.h>
  24 #include <stdbool.h>
  25 #include <string.h>
  26 #include <syslinux/config.h>
  27
  28 struct segoff16 {
  29   uint16_t offs, seg;
  30 };
  31
  32 struct s_PXENV_FILE_CHECK_API {
  33   uint16_t Status;
  34   uint16_t Size;
  35   uint32_t Magic;
  36   uint32_t Provider;
  37   uint32_t APIMask;
  38   uint32_t Flags;
  39 };
  40
  41 static bool is_gpxe(void)
  42 {
  43   const struct syslinux_version *sv;
  44   com32sys_t reg;
  45   struct s_PXENV_FILE_CHECK_API *fca;
  46
  47   sv = syslinux_version();
  48   if (sv->filesystem != SYSLINUX_FS_PXELINUX)
  49     return false;               /* Not PXELINUX */
  50
  51   fca = __com32.cs_bounce;
  52   memset(fca, 0, sizeof *fca);
  53   fca->Size  = sizeof *fca;
  54   fca->Magic = 0x91d447b2;
  55
  56   memset(&reg, 0, sizeof reg);
  57   reg.eax.w[0] = 0x0009;
  58   reg.ebx.w[0] = 0x00e6;        /* PXENV_FILE_API_CHECK */
  59   reg.edi.w[0] = OFFS(fca);
  60   reg.es       = SEG(fca);
  61
  62   __intcall(0x22, &reg, &reg);
  63
  64   if (reg.eflags.l & EFLAGS_CF)
  65     return false;               /* Cannot invoke PXE stack */
  66
  67   if (reg.eax.w[0] || fca->Status)
  68     return false;               /* PXE failure */
  69
  70   if (fca->Magic != 0xe9c17b20)
  71     return false;               /* Incorrect magic */
  72
  73   if (fca->Size < sizeof *fca)
  74     return false;               /* Short return */
  75
  76   if (!(fca->APIMask & (1 << 5)))
  77     return false;               /* No FILE EXEC */
  78
  79   return true;
  80 }
  81
  82 struct s_PXENV_FILE_EXEC {
  83   uint16_t Status;
  84   struct segoff16 Command;
  85 };
  86
  87 static void sanboot(const char **args)
  88 {
  89   char *q;
  90   struct s_PXENV_FILE_EXEC *fx;
  91   com32sys_t reg;
  92
  93   memset(&reg, 0, sizeof reg);
  94
  95   fx = __com32.cs_bounce;
  96   q = (char *)(fx+1);
  97
  98   fx->Status = 1;
  99   fx->Command.offs = OFFS(q);
 100   fx->Command.seg = SEG(q);
 101
 102   q = stpcpy(q, "sanboot");
 103
 104   while (*args) {
 105     *q++ = ' ';
 106     q = stpcpy(q, *args);
 107     args++;
 108   }
 109
 110   memset(&reg, 0, sizeof reg);
 111   reg.eax.w[0] = 0x0009;
 112   reg.ebx.w[0] = 0x00e5;        /* PXENV_FILE_EXEC */
 113   reg.edi.w[0] = OFFS(fx);
 114   reg.es       = SEG(fx);
 115
 116   __intcall(0x22, &reg, &reg);
 117
 118   /* This should not return... */
 119 }
 120
 121 int main(int argc, const char *argv[])
 122 {
 123   openconsole(&dev_null_r, &dev_stdcon_w);
 124
 125   if (argc < 2) {
 126     printf("Usage: sanboot rootpath\n");
 127     return 1;
 128   }
 129
 130   if (!is_gpxe()) {
 131     printf("sanboot: gPXE API not detected\n");
 132     return 1;
 133   }
 134
 135   sanboot(argv+1);
 136
 137   /* sanboot() should not return... */
 138   printf("SAN boot failed.\n");
 139   return 1;
 140 }