com32/sysdump/dmi.c

   1 /*
   2  * Dump DMI information in a way hopefully compatible with dmidecode
   3  */
   4
   5 #include <stdio.h>
   6 #include <string.h>
   7 #include <stdlib.h>
   8 #include "sysdump.h"
   9
  10 struct dmi_header {
  11     char signature[5];
  12     uint8_t csum;
  13     uint16_t tbllen;
  14     uint32_t tbladdr;
  15     uint16_t nstruc;
  16     uint8_t revision;
  17     uint8_t reserved;
  18 };
  19
  20 struct smbios_header {
  21     char signature[4];
  22     uint8_t csum;
  23     uint8_t len;
  24     uint8_t major;
  25     uint8_t minor;
  26     uint16_t maxsize;
  27     uint8_t revision;
  28     uint8_t fmt[5];
  29
  30     struct dmi_header dmi;
  31 };
  32
  33 static uint8_t checksum(const void *buf, size_t len)
  34 {
  35     const uint8_t *p = buf;
  36     uint8_t csum = 0;
  37
  38     while (len--)
  39         csum += *p++;
  40
  41     return csum;
  42 }
  43
  44 static bool is_old_dmi(size_t dptr)
  45 {
  46     const struct dmi_header *dmi = (void *)dptr;
  47
  48     return !memcmp(dmi->signature, "_DMI_", 5) &&
  49         !checksum(dmi, 0x0f);
  50     return false;
  51 }
  52
  53 static bool is_smbios(size_t dptr)
  54 {
  55     const struct smbios_header *smb = (void *)dptr;
  56
  57     return !memcmp(smb->signature, "_SM_", 4) &&
  58         !checksum(smb, smb->len) &&
  59         is_old_dmi(dptr+16);
  60 }
  61
  62 static void dump_smbios(struct upload_backend *be, size_t dptr)
  63 {
  64     const struct smbios_header *smb = (void *)dptr;
  65     struct smbios_header smx = *smb;
  66     char filename[32];
  67
  68     snprintf(filename, sizeof filename, "dmi/%05x.%08x",
  69              dptr, smb->dmi.tbladdr);
  70     cpio_hdr(be, MODE_FILE, smb->dmi.tbllen + 32, filename);
  71
  72     /*
  73      * Adjust the address of the smbios table to be 32, to
  74      * make dmidecode happy.  The checksum on the smbios table is unchanged,
  75      * since it includes the checksum on the dmi table.
  76      */
  77     smx.dmi.tbladdr = sizeof smx;
  78     smx.dmi.csum -= checksum(&smx.dmi, 0x0f);
  79
  80     write_data(be, &smx, sizeof smx);
  81     write_data(be, (const void *)smb->dmi.tbladdr, smb->dmi.tbllen);
  82 }
  83
  84 static void dump_old_dmi(struct upload_backend *be, size_t dptr)
  85 {
  86     const struct dmi_header *dmi = (void *)dptr;
  87     struct fake {
  88         struct dmi_header dmi;
  89         char pad[16];
  90     } fake;
  91     char filename[32];
  92
  93     snprintf(filename, sizeof filename, "dmi/%05x.%08x",
  94              dptr, dmi->tbladdr);
  95     cpio_hdr(be, MODE_FILE, dmi->tbllen + 32, filename);
  96
  97     /*
  98      * Adjust the address of the smbios table to be 32, to
  99      * make dmidecode happy.
 100      */
 101     fake.dmi = *dmi;
 102     memset(&fake.pad, 0, sizeof fake.pad);
 103     fake.dmi.tbladdr = sizeof fake;
 104     fake.dmi.csum -= checksum(&fake.dmi, 0x0f);
 105
 106     write_data(be, &fake, sizeof fake);
 107     write_data(be, (const void *)dmi->tbladdr, dmi->tbllen);
 108 }
 109
 110 void dump_dmi(struct upload_backend *be)
 111 {
 112     size_t dptr;
 113
 114     cpio_mkdir(be, "dmi");
 115
 116     /* Search for _SM_ or _DMI_ structure */
 117     for (dptr = 0xf0000 ; dptr < 0x100000 ; dptr += 16) {
 118         if (is_smbios(dptr)) {
 119             dump_smbios(be, dptr);
 120             dptr += 16;         /* Skip the subsequent DMI header */
 121         } else if (is_old_dmi(dptr)) {
 122             dump_old_dmi(be, dptr);
 123         }
 124     }
 125 }