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libusb.c

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/*!
 * @file libusb.c
 * @brief HID Library - Generic USB backend for Generic HID Access (using MGE HIDParser)
 *
 * @author Copyright (C) 2003
 *    Arnaud Quette <arnaud.quette@free.fr> && <arnaud.quette@mgeups.com>
 *      2005 Peter Selinger <selinger@users.sourceforge.net>
 *
 * This program is sponsored by MGE UPS SYSTEMS - opensource.mgeups.com
 *
 *      The logic of this file is ripped from mge-shut driver (also from
 *      Arnaud Quette), which is a "HID over serial link" UPS driver for
 *      Network UPS Tools <http://www.networkupstools.org/>
 *
 *      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 "config.h"

#include <stdio.h>
#include <string.h>
#include <sys/types.h>
#include <regex.h>
#include <usb.h>

#ifdef HAVE_STDINT_H
#include <stdint.h> /* for uint8_t, uint16_t */
#endif

#include "libhid.h"

#include "libusb.h"
#include "config.h" /* for LIBUSB_HAS_DETACH_KRNL_DRV flag */

#include "common.h" /* for xmalloc, upsdebugx prototypes */

/* USB standard state 5000, but we've decreased it to
 * improve reactivity */
#define USB_TIMEOUT 4000

#define USB_DRIVER_NAME       "USB communication driver 0.28"
#define USB_DRIVER_VERSION    "0.28"

/* HID descriptor, completed with desc{type,len} */
struct my_usb_hid_descriptor {
        uint8_t  bLength;
        uint8_t  bDescriptorType;  /* 0x21 */
        uint16_t bcdHID;
        uint8_t  bCountryCode;
        uint8_t  bNumDescriptors;
        uint8_t  bReportDescriptorType;
        uint16_t wDescriptorLength;
};

/* From usbutils: workaround libusb API goofs:  "byte" should never be sign extended;
 * using "char" is trouble.  Likewise, sizes should never be negative.
 */

static inline int typesafe_control_msg(usb_dev_handle *dev,
        unsigned char requesttype, unsigned char request,
        int value, int index,
        unsigned char *bytes, unsigned size, int timeout)
{
        return usb_control_msg(dev, requesttype, request, value, index,
                (char *) bytes, (int) size, timeout);
}

#define usb_control_msg         typesafe_control_msg

/* return report descriptor on success, NULL otherwise */
/* mode: MODE_OPEN for the 1rst time, MODE_REOPEN to skip getting
    report descriptor (the longer part). On success, fill in the
    curDevice structure and return the report descriptor length. On
    failure, return -1. Note: ReportDesc must point to a large enough
    buffer. There's no way to know the size ahead of time. Matcher is
    a linked list of matchers (see libhid.h), and the opened device
    must match all of them. */
static int libusb_open(usb_dev_handle **udevp, HIDDevice *curDevice, HIDDeviceMatcher_t *matcher, unsigned char *ReportDesc, int mode)
{
      int found = 0;
#if LIBUSB_HAS_DETACH_KRNL_DRV
      int retries;
#endif
      int rdlen; /* report descriptor length */
      int rdlen1, rdlen2; /* report descriptor length, method 1+2 */
      HIDDeviceMatcher_t *m;
      struct usb_device *dev;
      struct usb_bus *bus;
      usb_dev_handle *udev;
      struct usb_interface_descriptor *iface;
      
      int ret, res; 
      unsigned char buf[20];
      unsigned char *p;
      char string[256];
      int i;

      /* libusb base init */
      usb_init();
      usb_find_busses();
      usb_find_devices();

      for (bus = usb_busses; bus && !found; bus = bus->next) {
            for (dev = bus->devices; dev && !found; dev = dev->next) {
                  upsdebugx(2, "Checking device (%04X/%04X) (%s/%s)", dev->descriptor.idVendor, dev->descriptor.idProduct, bus->dirname, dev->filename);
                  
                  /* supported vendors are now checked by the
                     supplied matcher */

                  /* open the device */
                  *udevp = udev = usb_open(dev);
                  if (!udev) {
                        upsdebugx(2, "Failed to open device, skipping. (%s)", usb_strerror());
                        continue;
                  } 

                  /* collect the identifying information of this
                     device. Note that this is safe, because
                     there's no need to claim an interface for
                     this (and therefore we do not yet need to
                     detach any kernel drivers). */
                  
                  curDevice->VendorID = dev->descriptor.idVendor;
                  curDevice->ProductID = dev->descriptor.idProduct;
                  curDevice->Vendor = NULL;
                  curDevice->Product = NULL;
                  curDevice->Serial = NULL;
                  curDevice->Bus = bus->dirname;
                  
                  if (dev->descriptor.iManufacturer) {
                        ret = usb_get_string_simple(udev, dev->descriptor.iManufacturer, string, sizeof(string));
                        if (ret > 0) {
                              curDevice->Vendor = strdup(string);
                        }
                  }

                  if (dev->descriptor.iProduct) {
                        ret = usb_get_string_simple(udev, dev->descriptor.iProduct, string, sizeof(string));
                        if (ret > 0) {
                              curDevice->Product = strdup(string);
                        }
                  }

                  if (dev->descriptor.iSerialNumber) {
                        ret = usb_get_string_simple(udev, dev->descriptor.iSerialNumber, string, sizeof(string));
                        if (ret > 0) {
                              curDevice->Serial = strdup(string);
                        }
                  }

                  upsdebugx(2, "- VendorID: %04x", curDevice->VendorID);
                  upsdebugx(2, "- ProductID: %04x", curDevice->ProductID);
                  upsdebugx(2, "- Manufacturer: %s", curDevice->Vendor ? curDevice->Vendor : "unknown");
                  upsdebugx(2, "- Product: %s", curDevice->Product ? curDevice->Product : "unknown");
                  upsdebugx(2, "- Serial Number: %s", curDevice->Serial ? curDevice->Serial : "unknown");
                  upsdebugx(2, "- Bus: %s", curDevice->Bus ? curDevice->Bus : "unknown");

                  upsdebugx(2, "Trying to match device");
                  for (m = matcher; m; m=m->next) {
                        ret = matches(m, curDevice);
                        if (ret==0) {
                              upsdebugx(2, "Device does not match - skipping");
                              goto next_device;
                        } else if (ret==-1) {
                              fatalx("matcher: %s", strerror(errno));
                              goto next_device;
                        } else if (ret==-2) {
                              upsdebugx(2, "matcher: unspecified error");
                              goto next_device;
                        }
                  }
                  upsdebugx(2, "Device matches");
                  
                  /* Now we have matched the device we wanted. Claim it. */

#if LIBUSB_HAS_DETACH_KRNL_DRV
                  /* this method requires at least libusb 0.1.8:
                   * it force device claiming by unbinding
                   * attached driver... From libhid */
                  retries = 3;
                  while (usb_claim_interface(udev, 0) != 0 && retries-- > 0) {
                        
                        upsdebugx(2, "failed to claim USB device, trying %d more time(s)...", retries);
                        
                        upsdebugx(2, "detaching kernel driver from USB device...");
                        if (usb_detach_kernel_driver_np(udev, 0) < 0) {
                              upsdebugx(2, "failed to detach kernel driver from USB device...");
                        }
                        
                        upsdebugx(2, "trying again to claim USB device...");
                  }
#else
                  if (usb_claim_interface(udev, 0) < 0)
                        upsdebugx(2, "failed to claim USB device...");
#endif
                  
                  /* set default interface */
                  usb_set_altinterface(udev, 0);
                  
                  if (mode == MODE_REOPEN) {
                        return 1; 
                  }

                  if (!dev->config) { /* ?? this should never happen */
                        upsdebugx(2, "  Couldn't retrieve descriptors");
                        goto next_device;
                  }
                  
                  rdlen1 = -1;
                  rdlen2 = -1;

                  /* Get HID descriptor */

                  /* FIRST METHOD: ask for HID descriptor directly. */
                  /* res = usb_get_descriptor(udev, USB_DT_HID, 0, buf, 0x9); */
                  res = usb_control_msg(udev, USB_ENDPOINT_IN+1, USB_REQ_GET_DESCRIPTOR,
                                    (USB_DT_HID << 8) + 0, 0, buf, 0x9, USB_TIMEOUT);
                  
                  if (res < 0) {
                        upsdebugx(2, "Unable to get HID descriptor (%s)", usb_strerror());
                  } else if (res < 9) {
                        upsdebugx(2, "HID descriptor too short (expected %d, got %d)", 8, res);
                  } else {

                        upsdebug_hex(3, "HID descriptor, method 1", buf, 9);

                        rdlen1 = buf[7] | (buf[8] << 8);
                  }                 

                  if (rdlen1 < -1) {
                        upsdebugx(2, "Warning: HID descriptor, method 1 failed");
                  }

                  /* SECOND METHOD: find HID descriptor among "extra" bytes of
                     interface descriptor, i.e., bytes tucked onto the end of
                     descriptor 2. */

                  /* Note: on some broken UPS's (e.g. Tripp Lite Smart1000LCD),
                        only this second method gives the correct result */
                  
                  /* for now, we always assume configuration 0, interface 0,
                     altsetting 0, as above. */
                  iface = &dev->config[0].interface[0].altsetting[0];
                  for (i=0; i<iface->extralen; i+=iface->extra[i]) {
                        upsdebugx(4, "i=%d, extra[i]=%02x, extra[i+1]=%02x", i, iface->extra[i], iface->extra[i+1]);
                        if (i+9 <= iface->extralen && iface->extra[i] >= 9 && iface->extra[i+1] == 0x21) {
                              p = &iface->extra[i];
                              upsdebug_hex(3, "HID descriptor, method 2", p, 9);
                              rdlen2 = p[7] | (p[8] << 8);
                              break;
                        }
                  }

                  if (rdlen2 < -1) {
                        upsdebugx(2, "Warning: HID descriptor, method 2 failed");
                  }

                  /* when available, always choose the second value, as it
                        seems to be more reliable (it is the one reported e.g. by
                        lsusb). Note: if the need arises, can change this to use
                        the maximum of the two values instead. */
                  rdlen = rdlen2 >= 0 ? rdlen2 : rdlen1;

                  if (rdlen < 0) {
                        upsdebugx(2, "Unable to retrieve any HID descriptor");
                        goto next_device;
                  }
                  if (rdlen1 >= 0 && rdlen2 >= 0 && rdlen1 != rdlen2) {
                        upsdebugx(2, "Warning: two different HID descriptors retrieved (Reportlen = %u vs. %u)", rdlen1, rdlen2);
                  }

                  upsdebugx(2, "HID descriptor retrieved (Reportlen = %u)", rdlen);

                  /* res = usb_get_descriptor(udev, USB_DT_REPORT, 0, bigbuf, rdlen); */
                  res = usb_control_msg(udev, USB_ENDPOINT_IN+1, USB_REQ_GET_DESCRIPTOR,
                                    (USB_DT_REPORT << 8) + 0, 0, ReportDesc, 
                                    rdlen, USB_TIMEOUT);
                  if (res < 0)
                  {
                        upsdebugx(2, "Unable to get Report descriptor (%d): %s", res, strerror(-res));
                        goto next_device;
                  }
                  if (res < rdlen) 
                  {
                        upsdebugx(2, "Warning: report descriptor too short (expected %d, got %d)", rdlen, res);
                  }
                  if (res < rdlen) {
                        rdlen = res; /* correct rdlen if necessary */
                  }
                  upsdebugx(2, "Report descriptor retrieved (Reportlen = %u)", rdlen);
                  upsdebugx(2, "Found HID device");
                  fflush(stdout);

                  return rdlen;

            next_device:
                  usb_close(udev);
                  udev = NULL;
            }
      }
      upsdebugx(2, "No appropriate HID device found");
      fflush(stdout);

      return -1;
}

/* return the report of ID=type in report 
 * return -1 on failure, report length on success
 */

static int libusb_get_report(usb_dev_handle *udev, int ReportId, unsigned char *raw_buf, int ReportSize )
{
      upsdebugx(4, "Entering libusb_get_report");

      if (udev != NULL)
      {
            return usb_control_msg(udev, 
                   USB_ENDPOINT_IN + USB_TYPE_CLASS + USB_RECIP_INTERFACE,
                   0x01, /* HID_REPORT_GET */
                   ReportId+(0x03<<8), /* HID_REPORT_TYPE_FEATURE */
                   0, raw_buf, ReportSize, USB_TIMEOUT);
      }
      else
            return 0;
}


static int libusb_set_report(usb_dev_handle *udev, int ReportId, unsigned char *raw_buf, int ReportSize )
{
      if (udev != NULL)
      {
            return usb_control_msg(udev, 
                   USB_ENDPOINT_OUT + USB_TYPE_CLASS + USB_RECIP_INTERFACE,
                   0x09, /* HID_REPORT_SET = 0x09*/
                   ReportId+(0x03<<8), /* HID_REPORT_TYPE_FEATURE */
                   0, raw_buf, ReportSize, USB_TIMEOUT);
      }
      else
            return 0;
}

static int libusb_get_string(usb_dev_handle *udev, int StringIdx, char *string)
{
  int ret = -1;   

  if (udev != NULL)
      {
        ret = usb_get_string_simple(udev, StringIdx, string, 20); /* sizeof(string)); */
        if (ret > 0)
            {
              upsdebugx(5, "-> String: %s (len = %i/%i)", string, ret, sizeof(string));
            }
        else
              upsdebugx(2, "- Unable to fetch string %d", StringIdx);
      }

  return ret;
}

static int libusb_get_interrupt(usb_dev_handle *udev, unsigned char *buf, int bufsize, int timeout)
{
      int ret = -1;

#if SUN_LIBUSB
      /* sleep during timeout to slow down a bit... */
      sleep(timeout / 1000);
      ret = 0;
#else
      if (udev != NULL)
      {
            /* FIXME: hardcoded interrupt EP => need to get EP descr for IF descr */
            ret = usb_interrupt_read(udev, 0x81, (char *)buf, bufsize, timeout);
            if (ret > 0)
                  upsdebugx(6, " ok");
            else
                  upsdebugx(6, " none (%i)", ret);
      }
#endif
      return ret;
}

static void libusb_close(usb_dev_handle *udev)
{
      if (udev != NULL)
      {
            /* usb_release_interface() sometimes blocks and goes
            into uninterruptible sleep.  So don't do it. */
            /* usb_release_interface(udev, 0); */
            usb_close(udev);
      }
}

communication_subdriver_t usb_subdriver = {
      USB_DRIVER_VERSION,
      USB_DRIVER_NAME,
      libusb_open,
      libusb_close,
      libusb_get_report,
      libusb_set_report,
      libusb_get_string,
      libusb_get_interrupt
};

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