usbmisc.c

   1 /*****************************************************************************/
   2 /*
   3  *      usbmisc.c  --  Misc USB routines
   4  *
   5  *      Copyright (C) 2003  Aurelien Jarno (aurelien@aurel32.net)
   6  *
   7  *      This program is free software; you can redistribute it and/or modify
   8  *      it under the terms of the GNU General Public License as published by
   9  *      the Free Software Foundation; either version 2 of the License, or
  10  *      (at your option) any later version.
  11  *
  12  *      This program is distributed in the hope that it will be useful,
  13  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  15  *      GNU General Public License for more details.
  16  *
  17  *      You should have received a copy of the GNU General Public License
  18  *      along with this program; if not, write to the Free Software
  19  *      Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  20  *
  21  *
  22  */
  23
  24 /*****************************************************************************/
  25
  26 #include <stdio.h>
  27 #include <string.h>
  28
  29 #ifdef HAVE_CONFIG_H
  30 #include "config.h"
  31 #endif
  32
  33 #include "usbmisc.h"
  34
  35 /* ---------------------------------------------------------------------- */
  36
  37 static const char *devbususb = "/dev/bus/usb";
  38
  39 /* ---------------------------------------------------------------------- */
  40
  41 static int readlink_recursive(const char *path, char *buf, size_t bufsize)
  42 {
  43         char temp[PATH_MAX + 1];
  44         char *ptemp;
  45         int ret;
  46
  47         ret = readlink(path, buf, bufsize);
  48
  49         if (ret > 0) {
  50                 buf[ret] = 0;
  51                 if (*buf != '/')
  52                 {
  53                         strncpy(temp, path, sizeof(temp));
  54                         ptemp = temp + strlen(temp);
  55                         while (*ptemp != '/' && ptemp != temp) ptemp--;
  56                         ptemp++;
  57                         strncpy(ptemp, buf, bufsize + temp - ptemp);
  58                 }
  59                 else
  60                         strncpy(temp, buf, sizeof(temp));
  61                 return readlink_recursive(temp, buf, bufsize);
  62         }
  63         else {
  64                 strncpy(buf, path, bufsize);
  65                 return strlen(buf);
  66         }
  67 }
  68
  69 static char *get_absolute_path(const char *path, char *result, size_t result_size)
  70 {
  71         const char *ppath;      /* pointer on the input string */
  72         char *presult;          /* pointer on the output string */
  73
  74         ppath = path;
  75         presult = result;
  76         result[0] = 0;
  77
  78         if (path == NULL)
  79                 return result;
  80
  81         if (*ppath != '/') {
  82                 result = getcwd(result, result_size);
  83                 presult += strlen(result);
  84                 result_size -= strlen(result);
  85
  86                 *presult++ = '/';
  87                 result_size--;
  88         }
  89
  90         while (*ppath != 0 && result_size > 1) {
  91                 if (*ppath == '/') {
  92                         do ppath++; while (*ppath == '/');
  93                         *presult++ = '/';
  94                         result_size--;
  95                 }
  96                 else if (*ppath == '.' && *(ppath + 1) == '.' && *(ppath + 2) == '/' && *(presult - 1) == '/') {
  97                         if ((presult - 1) != result)
  98                         {
  99                                 /* go one directory upper */
 100                                 do {
 101                                         presult--;
 102                                         result_size++;
 103                                 } while (*(presult - 1) != '/');
 104                         }
 105                         ppath += 3;
 106                 }
 107                 else if (*ppath == '.'  && *(ppath + 1) == '/' && *(presult - 1) == '/') {
 108                         ppath += 2;
 109                 }
 110                 else {
 111                         *presult++ = *ppath++;
 112                         result_size--;
 113                 }
 114         }
 115         /* Don't forget to mark the end of the string! */
 116         *presult = 0;
 117
 118         return result;
 119 }
 120
 121 struct usb_device *get_usb_device(const char *path)
 122 {
 123         struct usb_bus *bus;
 124         struct usb_device *dev;
 125         char device_path[PATH_MAX + 1];
 126         char absolute_path[PATH_MAX + 1];
 127
 128         readlink_recursive(path, device_path, sizeof(device_path));
 129         get_absolute_path(device_path, absolute_path, sizeof(absolute_path));
 130
 131         for (bus = usb_busses; bus; bus = bus->next) {
 132                 for (dev = bus->devices; dev; dev = dev->next) {
 133                         snprintf(device_path, sizeof(device_path), "%s/%s/%s", devbususb, bus->dirname, dev->filename);
 134                         if (!strcmp(device_path, absolute_path))
 135                                 return dev;
 136                 }
 137         }
 138         return NULL;
 139 }
 140