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
  97   sysfs_obj_name(d, object, namebuf);
  98   fd = open(namebuf, O_RDONLY);
  99   if (fd < 0)
 100     {
 101       if (mandatory)
 102         a->error("Cannot open %s: %s", namebuf, strerror(errno));
 103       return 0;
 104     }
 105   n = read(fd, buf, OBJBUFSIZE);
 106   close(fd);
 107   if (n < 0)
 108     a->error("Error reading %s: %s", namebuf, strerror(errno));
 109   if (n >= OBJBUFSIZE)
 110     a->error("Value in %s too long", namebuf);
 111   buf[n] = 0;
 112   return 1;
 113 }
 114
 115 static int
 116 sysfs_get_value(struct pci_dev *d, char *object)
 117 {
 118   char buf[OBJBUFSIZE];
 119
 120   sysfs_get_string(d, object, buf, 1);
 121   return strtol(buf, NULL, 0);
 122 }
 123
 124 static void
 125 sysfs_get_resources(struct pci_dev *d)
 126 {
 127   struct pci_access *a = d->access;
 128   char namebuf[OBJNAMELEN], buf[256];
 129   FILE *file;
 130   int i;
 131
 132   sysfs_obj_name(d, "resource", namebuf);
 133   file = fopen(namebuf, "r");
 134   if (!file)
 135     a->error("Cannot open %s: %s", namebuf, strerror(errno));
 136   for (i = 0; i < 7; i++)
 137     {
 138       unsigned long long start, end, size, flags;
 139       if (!fgets(buf, sizeof(buf), file))
 140         break;
 141       if (sscanf(buf, "%llx %llx %llx", &start, &end, &flags) != 3)
 142         a->error("Syntax error in %s", namebuf);
 143       if (end > start)
 144         size = end - start + 1;
 145       else
 146         size = 0;
 147       flags &= PCI_ADDR_FLAG_MASK;
 148       if (i < 6)
 149         {
 150           d->base_addr[i] = start | flags;
 151           d->size[i] = size;
 152         }
 153       else
 154         {
 155           d->rom_base_addr = start | flags;
 156           d->rom_size = size;
 157         }
 158     }
 159   fclose(file);
 160 }
 161
 162 static void sysfs_scan(struct pci_access *a)
 163 {
 164   char dirname[1024];
 165   DIR *dir;
 166   struct dirent *entry;
 167   int n;
 168
 169   n = snprintf(dirname, sizeof(dirname), "%s/devices", sysfs_name(a));
 170   if (n < 0 || n >= (int) sizeof(dirname))
 171     a->error("Directory name too long");
 172   dir = opendir(dirname);
 173   if (!dir)
 174     a->error("Cannot open %s", dirname);
 175   while ((entry = readdir(dir)))
 176     {
 177       struct pci_dev *d;
 178       unsigned int dom, bus, dev, func;
 179
 180       /* ".", ".." or a special non-device perhaps */
 181       if (entry->d_name[0] == '.')
 182         continue;
 183
 184       d = pci_alloc_dev(a);
 185       if (sscanf(entry->d_name, "%x:%x:%x.%d", &dom, &bus, &dev, &func) < 4)
 186         a->error("sysfs_scan: Couldn't parse entry name %s", entry->d_name);
 187       d->domain = dom;
 188       d->bus = bus;
 189       d->dev = dev;
 190       d->func = func;
 191       if (!a->buscentric)
 192         {
 193           sysfs_get_resources(d);
 194           d->irq = sysfs_get_value(d, "irq");
 195           /*
 196            *  We could read these faster from the config registers, but we want to give
 197            *  the kernel a chance to fix up ID's and especially classes of broken devices.
 198            */
 199           d->vendor_id = sysfs_get_value(d, "vendor");
 200           d->device_id = sysfs_get_value(d, "device");
 201           d->device_class = sysfs_get_value(d, "class") >> 8;
 202           char buf[1024];
 203           if (sysfs_get_string(d, "label", buf, 0))
 204             d->label = pci_strdup(d->access, buf);
 205
 206           d->known_fields = PCI_FILL_IDENT | PCI_FILL_CLASS | PCI_FILL_IRQ | PCI_FILL_BASES | PCI_FILL_ROM_BASE | PCI_FILL_SIZES;
 207         }
 208       pci_link_dev(a, d);
 209     }
 210   closedir(dir);
 211 }
 212
 213 static void
 214 sysfs_fill_slots(struct pci_access *a)
 215 {
 216   char dirname[1024];
 217   DIR *dir;
 218   struct dirent *entry;
 219   int n;
 220
 221   n = snprintf(dirname, sizeof(dirname), "%s/slots", sysfs_name(a));
 222   if (n < 0 || n >= (int) sizeof(dirname))
 223     a->error("Directory name too long");
 224   dir = opendir(dirname);
 225   if (!dir)
 226     return;
 227
 228   while (entry = readdir(dir))
 229     {
 230       char namebuf[OBJNAMELEN], buf[16];
 231       FILE *file;
 232       unsigned int dom, bus, dev;
 233       int res = 0;
 234       struct pci_dev *d;
 235
 236       /* ".", ".." or a special non-device perhaps */
 237       if (entry->d_name[0] == '.')
 238         continue;
 239
 240       n = snprintf(namebuf, OBJNAMELEN, "%s/%s/%s", dirname, entry->d_name, "address");
 241       if (n < 0 || n >= OBJNAMELEN)
 242         a->error("File name too long");
 243       file = fopen(namebuf, "r");
 244       /*
 245        * Old versions of Linux had a fakephp which didn't have an 'address'
 246        * file.  There's no useful information to be gleaned from these
 247        * devices, pretend they're not there.
 248        */
 249       if (!file)
 250         continue;
 251
 252       if (!fgets(buf, sizeof(buf), file) || (res = sscanf(buf, "%x:%x:%x", &dom, &bus, &dev)) < 3)
 253         {
 254           /*
 255            * In some cases, the slot is not tied to a specific device before
 256            * a card gets inserted. This happens for example on IBM pSeries
 257            * and we need not warn about it.
 258            */
 259           if (res != 2)
 260             a->warning("sysfs_fill_slots: Couldn't parse entry address %s", buf);
 261         }
 262       else
 263         {
 264           for (d = a->devices; d; d = d->next)
 265             if (dom == d->domain && bus == d->bus && dev == d->dev && !d->phy_slot)
 266               d->phy_slot = pci_strdup(a, entry->d_name);
 267         }
 268       fclose(file);
 269     }
 270   closedir(dir);
 271 }
 272
 273 static int
 274 sysfs_fill_info(struct pci_dev *d, int flags)
 275 {
 276   if ((flags & PCI_FILL_PHYS_SLOT) && !(d->known_fields & PCI_FILL_PHYS_SLOT))
 277     {
 278       struct pci_dev *pd;
 279       sysfs_fill_slots(d->access);
 280       for (pd = d->access->devices; pd; pd = pd->next)
 281         pd->known_fields |= PCI_FILL_PHYS_SLOT;
 282     }
 283
 284   if ((flags & PCI_FILL_MODULE_ALIAS) && !(d->known_fields & PCI_FILL_MODULE_ALIAS))
 285     {
 286       char buf[OBJBUFSIZE];
 287       if (sysfs_get_string(d, "modalias", buf, 0))
 288         d->module_alias = pci_strdup(d->access, buf);
 289     }
 290
 291   return pci_generic_fill_info(d, flags);
 292 }
 293
 294 /* Intent of the sysfs_setup() caller */
 295 enum
 296   {
 297     SETUP_READ_CONFIG = 0,
 298     SETUP_WRITE_CONFIG = 1,
 299     SETUP_READ_VPD = 2
 300   };
 301
 302 static int
 303 sysfs_setup(struct pci_dev *d, int intent)
 304 {
 305   struct pci_access *a = d->access;
 306   char namebuf[OBJNAMELEN];
 307
 308   if (a->cached_dev != d || (intent == SETUP_WRITE_CONFIG && !a->fd_rw))
 309     {
 310       sysfs_flush_cache(a);
 311       a->cached_dev = d;
 312     }
 313
 314   if (intent == SETUP_READ_VPD)
 315     {
 316       if (a->fd_vpd < 0)
 317         {
 318           sysfs_obj_name(d, "vpd", namebuf);
 319           a->fd_vpd = open(namebuf, O_RDONLY);
 320           /* No warning on error; vpd may be absent or accessible only to root */
 321         }
 322       return a->fd_vpd;
 323     }
 324
 325   if (a->fd < 0)
 326     {
 327       sysfs_obj_name(d, "config", namebuf);
 328       a->fd_rw = a->writeable || intent == SETUP_WRITE_CONFIG;
 329       a->fd = open(namebuf, a->fd_rw ? O_RDWR : O_RDONLY);
 330       if (a->fd < 0)
 331         a->warning("Cannot open %s", namebuf);
 332       a->fd_pos = 0;
 333     }
 334   return a->fd;
 335 }
 336
 337 static int sysfs_read(struct pci_dev *d, int pos, byte *buf, int len)
 338 {
 339   int fd = sysfs_setup(d, SETUP_READ_CONFIG);
 340   int res;
 341
 342   if (fd < 0)
 343     return 0;
 344   res = do_read(d, fd, buf, len, pos);
 345   if (res < 0)
 346     {
 347       d->access->warning("sysfs_read: read failed: %s", strerror(errno));
 348       return 0;
 349     }
 350   else if (res != len)
 351     return 0;
 352   return 1;
 353 }
 354
 355 static int sysfs_write(struct pci_dev *d, int pos, byte *buf, int len)
 356 {
 357   int fd = sysfs_setup(d, SETUP_WRITE_CONFIG);
 358   int res;
 359
 360   if (fd < 0)
 361     return 0;
 362   res = do_write(d, fd, buf, len, pos);
 363   if (res < 0)
 364     {
 365       d->access->warning("sysfs_write: write failed: %s", strerror(errno));
 366       return 0;
 367     }
 368   else if (res != len)
 369     {
 370       d->access->warning("sysfs_write: tried to write %d bytes at %d, but only %d succeeded", len, pos, res);
 371       return 0;
 372     }
 373   return 1;
 374 }
 375
 376 #ifdef PCI_HAVE_DO_READ
 377
 378 /* pread() is not available and do_read() only works for a single fd, so we
 379  * cannot implement read_vpd properly. */
 380 static int sysfs_read_vpd(struct pci_dev *d, int pos, byte *buf, int len)
 381 {
 382   return 0;
 383 }
 384
 385 #else /* !PCI_HAVE_DO_READ */
 386
 387 static int sysfs_read_vpd(struct pci_dev *d, int pos, byte *buf, int len)
 388 {
 389   int fd = sysfs_setup(d, SETUP_READ_VPD);
 390   int res;
 391
 392   if (fd < 0)
 393     return 0;
 394   res = pread(fd, buf, len, pos);
 395   if (res < 0)
 396     {
 397       d->access->warning("sysfs_read_vpd: read failed: %s", strerror(errno));
 398       return 0;
 399     }
 400   else if (res != len)
 401     return 0;
 402   return 1;
 403 }
 404
 405 #endif /* PCI_HAVE_DO_READ */
 406
 407 static void sysfs_cleanup_dev(struct pci_dev *d)
 408 {
 409   struct pci_access *a = d->access;
 410
 411   if (a->cached_dev == d)
 412     sysfs_flush_cache(a);
 413 }
 414
 415 struct pci_methods pm_linux_sysfs = {
 416   "linux-sysfs",
 417   "The sys filesystem on Linux",
 418   sysfs_config,
 419   sysfs_detect,
 420   sysfs_init,
 421   sysfs_cleanup,
 422   sysfs_scan,
 423   sysfs_fill_info,
 424   sysfs_read,
 425   sysfs_write,
 426   sysfs_read_vpd,
 427   NULL,                                 /* init_dev */
 428   sysfs_cleanup_dev
 429 };