sys-utils/lscpu-dmi.c

   1 /*
   2  * lscpu-dmi - Module to parse SMBIOS information
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it would be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License along
  15  * with this program; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  *
  18  * Code originally taken from the dmidecode utility and slightly rewritten
  19  * to suite the needs of lscpu
  20  */
  21 #include <errno.h>
  22 #include <stdlib.h>
  23 #include <sys/types.h>
  24 #include <sys/stat.h>
  25 #include <fcntl.h>
  26 #include <unistd.h>
  27 #include <string.h>
  28 #include <stdio.h>
  29
  30 #include "lscpu.h"
  31
  32 #define _PATH_SYS_DMI    "/sys/firmware/dmi/tables/DMI"
  33
  34 #define WORD(x) (uint16_t)(*(const uint16_t *)(x))
  35 #define DWORD(x) (uint32_t)(*(const uint32_t *)(x))
  36
  37 struct dmi_header
  38 {
  39         uint8_t type;
  40         uint8_t length;
  41         uint16_t handle;
  42         uint8_t *data;
  43 };
  44
  45 static int checksum(const uint8_t *buf, size_t len)
  46 {
  47         uint8_t sum = 0;
  48         size_t a;
  49
  50         for (a = 0; a < len; a++)
  51                 sum += buf[a];
  52         return (sum == 0);
  53 }
  54
  55 static void *get_mem_chunk(size_t base, size_t len, const char *devmem)
  56 {
  57         void *p = NULL;
  58         int fd;
  59
  60         if ((fd = open(devmem, O_RDONLY)) < 0)
  61                 return NULL;
  62
  63         if (!(p = malloc(len)))
  64                 goto nothing;
  65         if (lseek(fd, base, SEEK_SET) == -1)
  66                 goto nothing;
  67         if (read_all(fd, p, len) == -1)
  68                 goto nothing;
  69
  70         close(fd);
  71         return p;
  72
  73 nothing:
  74         free(p);
  75         close(fd);
  76         return NULL;
  77 }
  78
  79 static void to_dmi_header(struct dmi_header *h, uint8_t *data)
  80 {
  81         h->type = data[0];
  82         h->length = data[1];
  83         h->handle = WORD(data + 2);
  84         h->data = data;
  85 }
  86
  87 static char *dmi_string(const struct dmi_header *dm, uint8_t s)
  88 {
  89         char *bp = (char *)dm->data;
  90
  91         if (s == 0)
  92                 return NULL;
  93
  94         bp += dm->length;
  95         while (s > 1 && *bp)
  96         {
  97                 bp += strlen(bp);
  98                 bp++;
  99                 s--;
 100         }
 101
 102         if (!*bp)
 103                 return NULL;
 104
 105         return bp;
 106 }
 107
 108 static int hypervisor_from_dmi_table(uint32_t base, uint16_t len,
 109                                 uint16_t num, const char *devmem)
 110 {
 111         uint8_t *buf;
 112         uint8_t *data;
 113         int i = 0;
 114         char *vendor = NULL;
 115         char *product = NULL;
 116         char *manufacturer = NULL;
 117         int rc = HYPER_NONE;
 118
 119         data = buf = get_mem_chunk(base, len, devmem);
 120         if (!buf)
 121                 goto done;
 122
 123          /* 4 is the length of an SMBIOS structure header */
 124         while (i < num && data + 4 <= buf + len) {
 125                 uint8_t *next;
 126                 struct dmi_header h;
 127
 128                 to_dmi_header(&h, data);
 129
 130                 /*
 131                  * If a short entry is found (less than 4 bytes), not only it
 132                  * is invalid, but we cannot reliably locate the next entry.
 133                  * Better stop at this point.
 134                  */
 135                 if (h.length < 4)
 136                         goto done;
 137
 138                 /* look for the next handle */
 139                 next = data + h.length;
 140                 while (next - buf + 1 < len && (next[0] != 0 || next[1] != 0))
 141                         next++;
 142                 next += 2;
 143                 switch (h.type) {
 144                         case 0:
 145                                 vendor = dmi_string(&h, data[0x04]);
 146                                 break;
 147                         case 1:
 148                                 manufacturer = dmi_string(&h, data[0x04]);
 149                                 product = dmi_string(&h, data[0x05]);
 150                                 break;
 151                         default:
 152                                 break;
 153                 }
 154
 155                 data = next;
 156                 i++;
 157         }
 158         if (manufacturer && !strcmp(manufacturer, "innotek GmbH"))
 159                 rc = HYPER_INNOTEK;
 160         else if (manufacturer && strstr(manufacturer, "HITACHI") &&
 161                                         product && strstr(product, "LPAR"))
 162                 rc = HYPER_HITACHI;
 163         else if (vendor && !strcmp(vendor, "Parallels"))
 164                 rc = HYPER_PARALLELS;
 165 done:
 166         free(buf);
 167         return rc;
 168 }
 169
 170 #if defined(__x86_64__) || defined(__i386__)
 171 static int hypervisor_decode_legacy(uint8_t *buf, const char *devmem)
 172 {
 173         if (!checksum(buf, 0x0F))
 174                 return -1;
 175
 176         return hypervisor_from_dmi_table(DWORD(buf + 0x08), WORD(buf + 0x06),
 177                          WORD(buf + 0x0C),
 178                 devmem);
 179 }
 180 #endif
 181
 182 static int hypervisor_decode_smbios(uint8_t *buf, const char *devmem)
 183 {
 184         if (!checksum(buf, buf[0x05])
 185             || memcmp(buf + 0x10, "_DMI_", 5) != 0
 186             || !checksum(buf + 0x10, 0x0F))
 187                 return -1;
 188
 189         return hypervisor_from_dmi_table(DWORD(buf + 0x18), WORD(buf + 0x16),
 190                          WORD(buf + 0x1C),
 191                 devmem);
 192 }
 193
 194 static int hypervisor_decode_sysfw(void)
 195 {
 196         static char const sys_fw_dmi_tables[] = _PATH_SYS_DMI;
 197         struct stat st;
 198
 199         if (stat(sys_fw_dmi_tables, &st))
 200                 return -1;
 201
 202         return hypervisor_from_dmi_table(0, st.st_size, st.st_size / 4,
 203                                          sys_fw_dmi_tables);
 204 }
 205
 206 /*
 207  * Probe for EFI interface
 208  */
 209 #define EFI_NOT_FOUND   (-1)
 210 #define EFI_NO_SMBIOS   (-2)
 211 static int address_from_efi(size_t *address)
 212 {
 213         FILE *tab;
 214         char linebuf[64];
 215         int ret;
 216
 217         *address = 0; /* Prevent compiler warning */
 218
 219         /*
 220          * Linux up to 2.6.6: /proc/efi/systab
 221          * Linux 2.6.7 and up: /sys/firmware/efi/systab
 222          */
 223         if (!(tab = fopen("/sys/firmware/efi/systab", "r")) &&
 224             !(tab = fopen("/proc/efi/systab", "r")))
 225                 return EFI_NOT_FOUND;           /* No EFI interface */
 226
 227         ret = EFI_NO_SMBIOS;
 228         while ((fgets(linebuf, sizeof(linebuf) - 1, tab)) != NULL) {
 229                 char *addrp = strchr(linebuf, '=');
 230                 if (!addrp)
 231                         continue;
 232                 *(addrp++) = '\0';
 233                 if (strcmp(linebuf, "SMBIOS") == 0) {
 234                         *address = strtoul(addrp, NULL, 0);
 235                         ret = 0;
 236                         break;
 237                 }
 238         }
 239
 240         fclose(tab);
 241         return ret;
 242 }
 243
 244 int read_hypervisor_dmi(void)
 245 {
 246         int rc = HYPER_NONE;
 247         uint8_t *buf = NULL;
 248         size_t fp = 0;
 249
 250         if (sizeof(uint8_t) != 1
 251             || sizeof(uint16_t) != 2
 252             || sizeof(uint32_t) != 4
 253             || '\0' != 0)
 254                 goto done;
 255
 256         /* -1 : no DMI in /sys,
 257          *  0 : DMI exist, nothing detected (HYPER_NONE)
 258          * >0 : hypervisor detected
 259          */
 260         rc = hypervisor_decode_sysfw();
 261         if (rc >= HYPER_NONE)
 262                 goto done;
 263
 264         /* First try EFI (ia64, Intel-based Mac) */
 265         switch (address_from_efi(&fp)) {
 266                 case EFI_NOT_FOUND:
 267                         goto memory_scan;
 268                 case EFI_NO_SMBIOS:
 269                         goto done;
 270         }
 271
 272         buf = get_mem_chunk(fp, 0x20, _PATH_DEV_MEM);
 273         if (!buf)
 274                 goto done;
 275
 276         rc = hypervisor_decode_smbios(buf, _PATH_DEV_MEM);
 277         if (rc >= HYPER_NONE)
 278                 goto done;
 279
 280         free(buf);
 281         buf = NULL;
 282 memory_scan:
 283 #if defined(__x86_64__) || defined(__i386__)
 284         /* Fallback to memory scan (x86, x86_64) */
 285         buf = get_mem_chunk(0xF0000, 0x10000, _PATH_DEV_MEM);
 286         if (!buf)
 287                 goto done;
 288
 289         for (fp = 0; fp <= 0xFFF0; fp += 16) {
 290                 if (memcmp(buf + fp, "_SM_", 4) == 0 && fp <= 0xFFE0) {
 291                         rc = hypervisor_decode_smbios(buf + fp, _PATH_DEV_MEM);
 292                         if (rc < 0)
 293                                 fp += 16;
 294
 295                 } else if (memcmp(buf + fp, "_DMI_", 5) == 0)
 296                         rc = hypervisor_decode_legacy(buf + fp, _PATH_DEV_MEM);
 297
 298                 if (rc >= HYPER_NONE)
 299                         break;
 300         }
 301 #endif
 302 done:
 303         free(buf);
 304         return rc < 0 ? HYPER_NONE : rc;
 305 }