lib/sysfs.c

   1 /*
   2  *      The PCI Library -- Configuration Access via /sys/bus/pci
   3  *
   4  *      Copyright (c) 2003 Matthew Wilcox <matthew@wil.cx>
   5  *      Copyright (c) 1997--2008 Martin Mares <mj@ucw.cz>
   6  *
   7  *      Can be freely distributed and used under the terms of the GNU GPL.
   8  */
   9
  10 #define _GNU_SOURCE
  11
  12 #include <stdio.h>
  13 #include <stdlib.h>
  14 #include <string.h>
  15 #include <stdarg.h>
  16 #include <unistd.h>
  17 #include <errno.h>
  18 #include <dirent.h>
  19 #include <fcntl.h>
  20 #include <sys/types.h>
  21
  22 #include "internal.h"
  23 #include "pread.h"
  24
  25 static void
  26 sysfs_config(struct pci_access *a)
  27 {
  28   pci_define_param(a, "sysfs.path", PCI_PATH_SYS_BUS_PCI, "Path to the sysfs device tree");
  29 }
  30
  31 static inline char *
  32 sysfs_name(struct pci_access *a)
  33 {
  34   return pci_get_param(a, "sysfs.path");
  35 }
  36
  37 static int
  38 sysfs_detect(struct pci_access *a)
  39 {
  40   if (access(sysfs_name(a), R_OK))
  41     {
  42       a->debug("...cannot open %s", sysfs_name(a));
  43       return 0;
  44     }
  45   a->debug("...using %s", sysfs_name(a));
  46   return 1;
  47 }
  48
  49 static void
  50 sysfs_init(struct pci_access *a)
  51 {
  52   a->fd = -1;
  53   a->fd_vpd = -1;
  54 }
  55
  56 static void
  57 sysfs_flush_cache(struct pci_access *a)
  58 {
  59   if (a->fd >= 0)
  60     {
  61       close(a->fd);
  62       a->fd = -1;
  63     }
  64   if (a->fd_vpd >= 0)
  65     {
  66       close(a->fd_vpd);
  67       a->fd_vpd = -1;
  68     }
  69   a->cached_dev = NULL;
  70 }
  71
  72 static void
  73 sysfs_cleanup(struct pci_access *a)
  74 {
  75   sysfs_flush_cache(a);
  76 }
  77
  78 #define OBJNAMELEN 1024
  79 static void
  80 sysfs_obj_name(struct pci_dev *d, char *object, char *buf)
  81 {
  82   int n = snprintf(buf, OBJNAMELEN, "%s/devices/%04x:%02x:%02x.%d/%s",
  83                    sysfs_name(d->access), d->domain, d->bus, d->dev, d->func, object);
  84   if (n < 0 || n >= OBJNAMELEN)
  85     d->access->error("File name too long");
  86 }
  87
  88 #define OBJBUFSIZE 1024
  89
  90 static int
  91 sysfs_get_string(struct pci_dev *d, char *object, char *buf, int mandatory)
  92 {
  93   struct pci_access *a = d->access;
  94   int fd, n;
  95   char namebuf[OBJNAMELEN];
  96   void (*warn)(char *msg, ...) = (mandatory ? a->error : a->warning);
  97
  98   sysfs_obj_name(d, object, namebuf);
  99   fd = open(namebuf, O_RDONLY);
 100   if (fd < 0)
 101     {
 102       if (mandatory || errno != ENOENT)
 103         warn("Cannot open %s: %s", namebuf, strerror(errno));
 104       return 0;
 105     }
 106   n = read(fd, buf, OBJBUFSIZE);
 107   close(fd);
 108   if (n < 0)
 109     {
 110       warn("Error reading %s: %s", namebuf, strerror(errno));
 111       return 0;
 112      }
 113   if (n >= OBJBUFSIZE)
 114     {
 115       warn("Value in %s too long", namebuf);
 116       return 0;
 117     }
 118   buf[n] = 0;
 119   return 1;
 120 }
 121
 122 static int
 123 sysfs_get_value(struct pci_dev *d, char *object, int mandatory)
 124 {
 125   char buf[OBJBUFSIZE];
 126
 127   if (sysfs_get_string(d, object, buf, mandatory))
 128     return strtol(buf, NULL, 0);
 129   else
 130     return -1;
 131 }
 132
 133 static void
 134 sysfs_get_resources(struct pci_dev *d)
 135 {
 136   struct pci_access *a = d->access;
 137   char namebuf[OBJNAMELEN], buf[256];
 138   FILE *file;
 139   int i;
 140
 141   sysfs_obj_name(d, "resource", namebuf);
 142   file = fopen(namebuf, "r");
 143   if (!file)
 144     a->error("Cannot open %s: %s", namebuf, strerror(errno));
 145   for (i = 0; i < 7; i++)
 146     {
 147       unsigned long long start, end, size, flags;
 148       if (!fgets(buf, sizeof(buf), file))
 149         break;
 150       if (sscanf(buf, "%llx %llx %llx", &start, &end, &flags) != 3)
 151         a->error("Syntax error in %s", namebuf);
 152       if (end > start)
 153         size = end - start + 1;
 154       else
 155         size = 0;
 156       if (i < 6)
 157         {
 158           d->flags[i] = flags;
 159           flags &= PCI_ADDR_FLAG_MASK;
 160           d->base_addr[i] = start | flags;
 161           d->size[i] = size;
 162         }
 163       else
 164         {
 165           d->rom_flags = flags;
 166           flags &= PCI_ADDR_FLAG_MASK;
 167           d->rom_base_addr = start | flags;
 168           d->rom_size = size;
 169         }
 170     }
 171   fclose(file);
 172 }
 173
 174 static void sysfs_scan(struct pci_access *a)
 175 {
 176   char dirname[1024];
 177   DIR *dir;
 178   struct dirent *entry;
 179   int n;
 180
 181   n = snprintf(dirname, sizeof(dirname), "%s/devices", sysfs_name(a));
 182   if (n < 0 || n >= (int) sizeof(dirname))
 183     a->error("Directory name too long");
 184   dir = opendir(dirname);
 185   if (!dir)
 186     a->error("Cannot open %s", dirname);
 187   while ((entry = readdir(dir)))
 188     {
 189       struct pci_dev *d;
 190       unsigned int dom, bus, dev, func;
 191
 192       /* ".", ".." or a special non-device perhaps */
 193       if (entry->d_name[0] == '.')
 194         continue;
 195
 196       d = pci_alloc_dev(a);
 197       if (sscanf(entry->d_name, "%x:%x:%x.%d", &dom, &bus, &dev, &func) < 4)
 198         a->error("sysfs_scan: Couldn't parse entry name %s", entry->d_name);
 199
 200       /* Ensure kernel provided domain that fits in a signed integer */
 201       if (dom > 0x7fffffff)
 202         a->error("sysfs_scan: Invalid domain %x", dom);
 203
 204       d->domain = dom;
 205       d->bus = bus;
 206       d->dev = dev;
 207       d->func = func;
 208       if (!a->buscentric)
 209         {
 210           sysfs_get_resources(d);
 211           d->irq = sysfs_get_value(d, "irq", 1);
 212           /*
 213            *  We could read these faster from the config registers, but we want to give
 214            *  the kernel a chance to fix up ID's and especially classes of broken devices.
 215            */
 216           d->vendor_id = sysfs_get_value(d, "vendor", 1);
 217           d->device_id = sysfs_get_value(d, "device", 1);
 218           d->device_class = sysfs_get_value(d, "class", 1) >> 8;
 219           d->known_fields = PCI_FILL_IDENT | PCI_FILL_CLASS | PCI_FILL_IRQ | PCI_FILL_BASES | PCI_FILL_ROM_BASE | PCI_FILL_SIZES | PCI_FILL_IO_FLAGS;
 220         }
 221       pci_link_dev(a, d);
 222     }
 223   closedir(dir);
 224 }
 225
 226 static void
 227 sysfs_fill_slots(struct pci_access *a)
 228 {
 229   char dirname[1024];
 230   DIR *dir;
 231   struct dirent *entry;
 232   int n;
 233
 234   n = snprintf(dirname, sizeof(dirname), "%s/slots", sysfs_name(a));
 235   if (n < 0 || n >= (int) sizeof(dirname))
 236     a->error("Directory name too long");
 237   dir = opendir(dirname);
 238   if (!dir)
 239     return;
 240
 241   while (entry = readdir(dir))
 242     {
 243       char namebuf[OBJNAMELEN], buf[16];
 244       FILE *file;
 245       unsigned int dom, bus, dev;
 246       int res = 0;
 247       struct pci_dev *d;
 248
 249       /* ".", ".." or a special non-device perhaps */
 250       if (entry->d_name[0] == '.')
 251         continue;
 252
 253       n = snprintf(namebuf, OBJNAMELEN, "%s/%s/%s", dirname, entry->d_name, "address");
 254       if (n < 0 || n >= OBJNAMELEN)
 255         a->error("File name too long");
 256       file = fopen(namebuf, "r");
 257       /*
 258        * Old versions of Linux had a fakephp which didn't have an 'address'
 259        * file.  There's no useful information to be gleaned from these
 260        * devices, pretend they're not there.
 261        */
 262       if (!file)
 263         continue;
 264
 265       if (!fgets(buf, sizeof(buf), file) || (res = sscanf(buf, "%x:%x:%x", &dom, &bus, &dev)) < 3)
 266         {
 267           /*
 268            * In some cases, the slot is not tied to a specific device before
 269            * a card gets inserted. This happens for example on IBM pSeries
 270            * and we need not warn about it.
 271            */
 272           if (res != 2)
 273             a->warning("sysfs_fill_slots: Couldn't parse entry address %s", buf);
 274         }
 275       else
 276         {
 277           for (d = a->devices; d; d = d->next)
 278             if (dom == (unsigned)d->domain && bus == d->bus && dev == d->dev && !d->phy_slot)
 279               d->phy_slot = pci_strdup(a, entry->d_name);
 280         }
 281       fclose(file);
 282     }
 283   closedir(dir);
 284 }
 285
 286 static int
 287 sysfs_fill_info(struct pci_dev *d, int flags)
 288 {
 289   if ((flags & PCI_FILL_PHYS_SLOT) && !(d->known_fields & PCI_FILL_PHYS_SLOT))
 290     {
 291       struct pci_dev *pd;
 292       sysfs_fill_slots(d->access);
 293       for (pd = d->access->devices; pd; pd = pd->next)
 294         pd->known_fields |= PCI_FILL_PHYS_SLOT;
 295     }
 296
 297   if ((flags & PCI_FILL_MODULE_ALIAS) && !(d->known_fields & PCI_FILL_MODULE_ALIAS))
 298     {
 299       char buf[OBJBUFSIZE];
 300       if (sysfs_get_string(d, "modalias", buf, 0))
 301         d->module_alias = pci_strdup(d->access, buf);
 302     }
 303
 304   if ((flags & PCI_FILL_LABEL) && !(d->known_fields & PCI_FILL_LABEL))
 305     {
 306       char buf[OBJBUFSIZE];
 307       if (sysfs_get_string(d, "label", buf, 0))
 308         d->label = pci_strdup(d->access, buf);
 309     }
 310
 311   if ((flags & PCI_FILL_NUMA_NODE) && !(d->known_fields & PCI_FILL_NUMA_NODE))
 312     d->numa_node = sysfs_get_value(d, "numa_node", 0);
 313
 314   return pci_generic_fill_info(d, flags);
 315 }
 316
 317 /* Intent of the sysfs_setup() caller */
 318 enum
 319   {
 320     SETUP_READ_CONFIG = 0,
 321     SETUP_WRITE_CONFIG = 1,
 322     SETUP_READ_VPD = 2
 323   };
 324
 325 static int
 326 sysfs_setup(struct pci_dev *d, int intent)
 327 {
 328   struct pci_access *a = d->access;
 329   char namebuf[OBJNAMELEN];
 330
 331   if (a->cached_dev != d || (intent == SETUP_WRITE_CONFIG && !a->fd_rw))
 332     {
 333       sysfs_flush_cache(a);
 334       a->cached_dev = d;
 335     }
 336
 337   if (intent == SETUP_READ_VPD)
 338     {
 339       if (a->fd_vpd < 0)
 340         {
 341           sysfs_obj_name(d, "vpd", namebuf);
 342           a->fd_vpd = open(namebuf, O_RDONLY);
 343           /* No warning on error; vpd may be absent or accessible only to root */
 344         }
 345       return a->fd_vpd;
 346     }
 347
 348   if (a->fd < 0)
 349     {
 350       sysfs_obj_name(d, "config", namebuf);
 351       a->fd_rw = a->writeable || intent == SETUP_WRITE_CONFIG;
 352       a->fd = open(namebuf, a->fd_rw ? O_RDWR : O_RDONLY);
 353       if (a->fd < 0)
 354         a->warning("Cannot open %s", namebuf);
 355       a->fd_pos = 0;
 356     }
 357   return a->fd;
 358 }
 359
 360 static int sysfs_read(struct pci_dev *d, int pos, byte *buf, int len)
 361 {
 362   int fd = sysfs_setup(d, SETUP_READ_CONFIG);
 363   int res;
 364
 365   if (fd < 0)
 366     return 0;
 367   res = do_read(d, fd, buf, len, pos);
 368   if (res < 0)
 369     {
 370       d->access->warning("sysfs_read: read failed: %s", strerror(errno));
 371       return 0;
 372     }
 373   else if (res != len)
 374     return 0;
 375   return 1;
 376 }
 377
 378 static int sysfs_write(struct pci_dev *d, int pos, byte *buf, int len)
 379 {
 380   int fd = sysfs_setup(d, SETUP_WRITE_CONFIG);
 381   int res;
 382
 383   if (fd < 0)
 384     return 0;
 385   res = do_write(d, fd, buf, len, pos);
 386   if (res < 0)
 387     {
 388       d->access->warning("sysfs_write: write failed: %s", strerror(errno));
 389       return 0;
 390     }
 391   else if (res != len)
 392     {
 393       d->access->warning("sysfs_write: tried to write %d bytes at %d, but only %d succeeded", len, pos, res);
 394       return 0;
 395     }
 396   return 1;
 397 }
 398
 399 #ifdef PCI_HAVE_DO_READ
 400
 401 /* pread() is not available and do_read() only works for a single fd, so we
 402  * cannot implement read_vpd properly. */
 403 static int sysfs_read_vpd(struct pci_dev *d, int pos, byte *buf, int len)
 404 {
 405   return 0;
 406 }
 407
 408 #else /* !PCI_HAVE_DO_READ */
 409
 410 static int sysfs_read_vpd(struct pci_dev *d, int pos, byte *buf, int len)
 411 {
 412   int fd = sysfs_setup(d, SETUP_READ_VPD);
 413   int res;
 414
 415   if (fd < 0)
 416     return 0;
 417   res = pread(fd, buf, len, pos);
 418   if (res < 0)
 419     {
 420       d->access->warning("sysfs_read_vpd: read failed: %s", strerror(errno));
 421       return 0;
 422     }
 423   else if (res != len)
 424     return 0;
 425   return 1;
 426 }
 427
 428 #endif /* PCI_HAVE_DO_READ */
 429
 430 static void sysfs_cleanup_dev(struct pci_dev *d)
 431 {
 432   struct pci_access *a = d->access;
 433
 434   if (a->cached_dev == d)
 435     sysfs_flush_cache(a);
 436 }
 437
 438 struct pci_methods pm_linux_sysfs = {
 439   "linux-sysfs",
 440   "The sys filesystem on Linux",
 441   sysfs_config,
 442   sysfs_detect,
 443   sysfs_init,
 444   sysfs_cleanup,
 445   sysfs_scan,
 446   sysfs_fill_info,
 447   sysfs_read,
 448   sysfs_write,
 449   sysfs_read_vpd,
 450   NULL,                                 /* init_dev */
 451   sysfs_cleanup_dev
 452 };