lib/proc.c

   1 /*
   2  *      The PCI Library -- Configuration Access via /proc/bus/pci
   3  *
   4  *      Copyright (c) 1997--2023 Martin Mares <mj@ucw.cz>
   5  *
   6  *      Can be freely distributed and used under the terms of the GNU GPL v2+.
   7  *
   8  *      SPDX-License-Identifier: GPL-2.0-or-later
   9  */
  10
  11 #define _GNU_SOURCE
  12
  13 #include <stdio.h>
  14 #include <string.h>
  15 #include <unistd.h>
  16 #include <ctype.h>
  17 #include <errno.h>
  18 #include <fcntl.h>
  19 #include <sys/types.h>
  20
  21 #include "internal.h"
  22
  23 static void
  24 proc_config(struct pci_access *a)
  25 {
  26   pci_define_param(a, "proc.path", PCI_PATH_PROC_BUS_PCI, "Path to the procfs bus tree");
  27 }
  28
  29 static int
  30 proc_detect(struct pci_access *a)
  31 {
  32   char *name = pci_get_param(a, "proc.path");
  33
  34   if (access(name, R_OK))
  35     {
  36       a->warning("Cannot open %s", name);
  37       return 0;
  38     }
  39   a->debug("...using %s", name);
  40   return 1;
  41 }
  42
  43 static void
  44 proc_init(struct pci_access *a)
  45 {
  46   a->fd = -1;
  47 }
  48
  49 static void
  50 proc_cleanup(struct pci_access *a)
  51 {
  52   if (a->fd >= 0)
  53     {
  54       close(a->fd);
  55       a->fd = -1;
  56     }
  57 }
  58
  59 static void
  60 proc_scan(struct pci_access *a)
  61 {
  62   FILE *f;
  63   char buf[512];
  64
  65   if (snprintf(buf, sizeof(buf), "%s/devices", pci_get_param(a, "proc.path")) == sizeof(buf))
  66     a->error("File name too long");
  67   f = fopen(buf, "r");
  68   if (!f)
  69     a->error("Cannot open %s", buf);
  70   while (fgets(buf, sizeof(buf)-1, f))
  71     {
  72       struct pci_dev *d = pci_alloc_dev(a);
  73       unsigned int dfn, vend, cnt, known;
  74       char *driver;
  75       int offset;
  76
  77 #define F " " PCIADDR_T_FMT
  78       cnt = sscanf(buf, "%x %x %x" F F F F F F F F F F F F F F "%n",
  79              &dfn,
  80              &vend,
  81              &d->irq,
  82              &d->base_addr[0],
  83              &d->base_addr[1],
  84              &d->base_addr[2],
  85              &d->base_addr[3],
  86              &d->base_addr[4],
  87              &d->base_addr[5],
  88              &d->rom_base_addr,
  89              &d->size[0],
  90              &d->size[1],
  91              &d->size[2],
  92              &d->size[3],
  93              &d->size[4],
  94              &d->size[5],
  95              &d->rom_size,
  96              &offset);
  97 #undef F
  98       if (cnt != 9 && cnt != 10 && cnt != 17)
  99         a->error("proc: parse error (read only %d items)", cnt);
 100       d->bus = dfn >> 8U;
 101       d->dev = PCI_SLOT(dfn & 0xff);
 102       d->func = PCI_FUNC(dfn & 0xff);
 103       d->vendor_id = vend >> 16U;
 104       d->device_id = vend & 0xffff;
 105       known = 0;
 106       if (!a->buscentric)
 107         {
 108           known |= PCI_FILL_IDENT | PCI_FILL_IRQ | PCI_FILL_BASES;
 109           if (cnt >= 10)
 110             known |= PCI_FILL_ROM_BASE;
 111           if (cnt >= 17)
 112             known |= PCI_FILL_SIZES;
 113         }
 114       if (cnt >= 17)
 115         {
 116           while (buf[offset] && isspace(buf[offset]))
 117             ++offset;
 118           driver = &buf[offset];
 119           while (buf[offset] && !isspace(buf[offset]))
 120             ++offset;
 121           buf[offset] = '\0';
 122           if (driver[0])
 123             {
 124               pci_set_property(d, PCI_FILL_DRIVER, driver);
 125               known |= PCI_FILL_DRIVER;
 126             }
 127         }
 128       d->known_fields = known;
 129       pci_link_dev(a, d);
 130     }
 131   fclose(f);
 132 }
 133
 134 static int
 135 proc_setup(struct pci_dev *d, int rw)
 136 {
 137   struct pci_access *a = d->access;
 138
 139   if (a->cached_dev != d || a->fd_rw < rw)
 140     {
 141       char buf[1024];
 142       int e;
 143       if (a->fd >= 0)
 144         close(a->fd);
 145       e = snprintf(buf, sizeof(buf), "%s/%02x/%02x.%d",
 146                    pci_get_param(a, "proc.path"),
 147                    d->bus, d->dev, d->func);
 148       if (e < 0 || e >= (int) sizeof(buf))
 149         a->error("File name too long");
 150       a->fd_rw = a->writeable || rw;
 151       a->fd = open(buf, a->fd_rw ? O_RDWR : O_RDONLY);
 152       if (a->fd < 0)
 153         {
 154           e = snprintf(buf, sizeof(buf), "%s/%04x:%02x/%02x.%d",
 155                        pci_get_param(a, "proc.path"),
 156                        d->domain, d->bus, d->dev, d->func);
 157           if (e < 0 || e >= (int) sizeof(buf))
 158             a->error("File name too long");
 159           a->fd = open(buf, a->fd_rw ? O_RDWR : O_RDONLY);
 160         }
 161       if (a->fd < 0)
 162         a->warning("Cannot open %s", buf);
 163       a->cached_dev = d;
 164     }
 165   return a->fd;
 166 }
 167
 168 static int
 169 proc_read(struct pci_dev *d, int pos, byte *buf, int len)
 170 {
 171   int fd = proc_setup(d, 0);
 172   int res;
 173
 174   if (fd < 0)
 175     return 0;
 176   res = pread(fd, buf, len, pos);
 177   if (res < 0)
 178     {
 179       d->access->warning("proc_read: read failed: %s", strerror(errno));
 180       return 0;
 181     }
 182   else if (res != len)
 183     return 0;
 184   return 1;
 185 }
 186
 187 static int
 188 proc_write(struct pci_dev *d, int pos, byte *buf, int len)
 189 {
 190   int fd = proc_setup(d, 1);
 191   int res;
 192
 193   if (fd < 0)
 194     return 0;
 195   res = pwrite(fd, buf, len, pos);
 196   if (res < 0)
 197     {
 198       d->access->warning("proc_write: write failed: %s", strerror(errno));
 199       return 0;
 200     }
 201   else if (res != len)
 202     {
 203       d->access->warning("proc_write: tried to write %d bytes at %d, but only %d succeeded", len, pos, res);
 204       return 0;
 205     }
 206   return 1;
 207 }
 208
 209 static void
 210 proc_cleanup_dev(struct pci_dev *d)
 211 {
 212   if (d->access->cached_dev == d)
 213     d->access->cached_dev = NULL;
 214 }
 215
 216 struct pci_methods pm_linux_proc = {
 217   .name = "linux-proc",
 218   .help = "The proc file system on Linux",
 219   .config = proc_config,
 220   .detect = proc_detect,
 221   .init = proc_init,
 222   .cleanup = proc_cleanup,
 223   .scan = proc_scan,
 224   .fill_info = pci_generic_fill_info,
 225   .read = proc_read,
 226   .write = proc_write,
 227   .cleanup_dev = proc_cleanup_dev,
 228 };