usbmisc.c

C code posted by gregkh
created at 07 Jul 13:52

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/*****************************************************************************/
/*
 *      usbmisc.c  --  Misc USB routines
 *
 *      Copyright (C) 2003  Aurelien Jarno (aurelien@aurel32.net)
 *
 *      This program is free software; you can redistribute it and/or modify
 *      it under the terms of the GNU General Public License as published by
 *      the Free Software Foundation; either version 2 of the License, or
 *      (at your option) any later version.
 *
 *      This program is distributed in the hope that it will be useful,
 *      but WITHOUT ANY WARRANTY; without even the implied warranty of
 *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *      GNU General Public License for more details.
 *
 *      You should have received a copy of the GNU General Public License
 *      along with this program; if not, write to the Free Software
 *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 *
 *
 */

/*****************************************************************************/

#include <stdio.h>
#include <string.h>

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include "usbmisc.h"

/* ---------------------------------------------------------------------- */

static const char *devbususb = "/dev/bus/usb";

/* ---------------------------------------------------------------------- */

static int readlink_recursive(const char *path, char *buf, size_t bufsize)
{
  char temp[PATH_MAX + 1];
  char *ptemp;
  int ret;

  ret = readlink(path, buf, bufsize);

  if (ret > 0) {
    buf[ret] = 0;
    if (*buf != '/') {
      strncpy(temp, path, sizeof(temp));
      ptemp = temp + strlen(temp);
      while (*ptemp != '/' && ptemp != temp)
        ptemp--;
      ptemp++;
      strncpy(ptemp, buf, bufsize + temp - ptemp);
    } else
      strncpy(temp, buf, sizeof(temp));
    return readlink_recursive(temp, buf, bufsize);
  } else {
    strncpy(buf, path, bufsize);
    return strlen(buf);
  }
}

static char *get_absolute_path(const char *path, char *result,
             size_t result_size)
{
  const char *ppath;  /* pointer on the input string */
  char *presult;    /* pointer on the output string */

  ppath = path;
  presult = result;
  result[0] = 0;

  if (path == NULL)
    return result;

  if (*ppath != '/') {
    result = getcwd(result, result_size);
    presult += strlen(result);
    result_size -= strlen(result);

    *presult++ = '/';
    result_size--;
  }

  while (*ppath != 0 && result_size > 1) {
    if (*ppath == '/') {
      do
        ppath++;
      while (*ppath == '/');
      *presult++ = '/';
      result_size--;
    } else if (*ppath == '.' && *(ppath + 1) == '.' &&
         *(ppath + 2) == '/' && *(presult - 1) == '/') {
      if ((presult - 1) != result) {
        /* go one directory upper */
        do {
          presult--;
          result_size++;
        } while (*(presult - 1) != '/');
      }
      ppath += 3;
    } else if (*ppath == '.'  &&
         *(ppath + 1) == '/' &&
         *(presult - 1) == '/') {
      ppath += 2;
    } else {
      *presult++ = *ppath++;
      result_size--;
    }
  }
  /* Don't forget to mark the end of the string! */
  *presult = 0;

  return result;
}

struct usb_device *get_usb_device(const char *path)
{
  struct usb_bus *bus;
  struct usb_device *dev;
  char device_path[PATH_MAX + 1];
  char absolute_path[PATH_MAX + 1];

  readlink_recursive(path, device_path, sizeof(device_path));
  get_absolute_path(device_path, absolute_path, sizeof(absolute_path));

  for (bus = usb_busses; bus; bus = bus->next) {
    for (dev = bus->devices; dev; dev = dev->next) {
      snprintf(device_path, sizeof(device_path), "%s/%s/%s",
         devbususb, bus->dirname, dev->filename);
      if (!strcmp(device_path, absolute_path))
        return dev;
    }
  }
  return NULL;
}
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