[Spice-devel] [PATCH spice-streaming-agent 6/8 v3] Interface + implementation of getting device display info

Jonathon Jongsma jjongsma at redhat.com
Thu Jan 17 20:09:31 UTC 2019


A couple minor comments below.

On Wed, 2019-01-16 at 13:52 +0100, Lukáš Hrázký wrote:
> Adds an interface method to the FrameCapture class to get the device
> display info (device address and device display id) for each display
> of
> the graphics device that is captured.
> 
> Also adds functions to the API implementing this functionality for
> X11
> in variants with and without DRM (the non-DRM version is rather
> limited
> and may not work for more complex setups) as well as some helper
> functions to make it easier for plugins to implement this and avoid
> code
> duplication.
> 
> Implements the new interface method for the two built-in plugins
> (mjpeg-fallback and gst-plugin).
> 
> Signed-off-by: Lukáš Hrázký <lhrazky at redhat.com>
> ---
>  configure.ac                                  |   2 +
>  include/spice-streaming-agent/Makefile.am     |   2 +
>  .../spice-streaming-agent/display-info.hpp    |  52 +++
>  .../spice-streaming-agent/frame-capture.hpp   |  13 +
>  .../x11-display-info.hpp                      |  57 ++++
>  src/Makefile.am                               |   7 +
>  src/display-info.cpp                          | 100 ++++++
>  src/gst-plugin.cpp                            |  14 +
>  src/mjpeg-fallback.cpp                        |  17 +-
>  src/spice-streaming-agent.cpp                 |  13 +
>  src/unittests/Makefile.am                     |   6 +
>  src/utils.cpp                                 |  46 +++
>  src/utils.hpp                                 |   4 +
>  src/x11-display-info.cpp                      | 302
> ++++++++++++++++++
>  14 files changed, 633 insertions(+), 2 deletions(-)
>  create mode 100644 include/spice-streaming-agent/display-info.hpp
>  create mode 100644 include/spice-streaming-agent/x11-display-
> info.hpp
>  create mode 100644 src/display-info.cpp
>  create mode 100644 src/utils.cpp
>  create mode 100644 src/x11-display-info.cpp
> 
> diff --git a/configure.ac b/configure.ac
> index e66e6d8..fd18efe 100644
> --- a/configure.ac
> +++ b/configure.ac
> @@ -34,8 +34,10 @@ SPICE_PROTOCOL_MIN_VER=0.12.14
>  PKG_CHECK_MODULES([SPICE_PROTOCOL], [spice-protocol >=
> $SPICE_PROTOCOL_MIN_VER])
>  AC_SUBST([SPICE_PROTOCOL_MIN_VER])
>  
> +PKG_CHECK_MODULES(DRM, libdrm)
>  PKG_CHECK_MODULES(X11, x11)
>  PKG_CHECK_MODULES(XFIXES, xfixes)
> +PKG_CHECK_MODULES(XRANDR, xrandr)
>  
>  PKG_CHECK_MODULES(JPEG, libjpeg, , [
>      AC_CHECK_LIB(jpeg, jpeg_destroy_decompress,
> diff --git a/include/spice-streaming-agent/Makefile.am
> b/include/spice-streaming-agent/Makefile.am
> index bcd679b..96c1a57 100644
> --- a/include/spice-streaming-agent/Makefile.am
> +++ b/include/spice-streaming-agent/Makefile.am
> @@ -1,8 +1,10 @@
>  NULL =
>  public_includedir = $(includedir)/spice-streaming-agent
>  public_include_HEADERS = \
> +	display-info.hpp \
>  	error.hpp \
>  	frame-capture.hpp \
>  	plugin.hpp \
> +	x11-display-info.hpp \
>  	$(NULL)
>  
> diff --git a/include/spice-streaming-agent/display-info.hpp
> b/include/spice-streaming-agent/display-info.hpp
> new file mode 100644
> index 0000000..f16212b
> --- /dev/null
> +++ b/include/spice-streaming-agent/display-info.hpp
> @@ -0,0 +1,52 @@
> +/* \copyright
> + * Copyright 2018 Red Hat Inc. All rights reserved.
> + */
> +
> +#ifndef SPICE_STREAMING_AGENT_DISPLAY_INFO_HPP
> +#define SPICE_STREAMING_AGENT_DISPLAY_INFO_HPP
> +
> +#include <vector>
> +#include <string>
> +
> +
> +namespace spice __attribute__ ((visibility ("default"))) {
> +namespace streaming_agent {
> +
> +/**
> + * Lists graphics cards listed in the DRM sybsystem in
> /sys/class/drm.
> + * Throws an instance of Error in case of an I/O error.
> + *
> + * @return a vector of paths of all graphics cards present in
> /sys/class/drm
> + */
> +std::vector<std::string> list_cards();
> +
> +/**
> + * Reads a single number in hex format from a file.
> + * Throws an instance of Error in case of an I/O or parsing error.
> + *
> + * @param path the path to the file
> + * @return the number parsed from the file
> + */
> +uint32_t read_hex_number_from_file(const std::string &path);
> +
> +/**
> + * Resolves any symlinks and then extracts the PCI path from the
> canonical path
> + * to a card. Returns the path in the following format:
> + * "pci/<DOMAIN>/<SLOT>.<FUNCTION>/.../<SLOT>.<FUNCTION>"
> + *
> + * <DOMAIN> is the PCI domain, followed by <SLOT>.<FUNCTION> of any
> PCI bridges
> + * in the chain leading to the device. The last <SLOT>.<FUNCTION> is
> the
> + * graphics device. All of <DOMAIN>, <SLOT>, <FUNCTION> are
> hexadecimal numbers
> + * with the following number of digits:
> + *   <DOMAIN>: 4
> + *   <SLOT>: 2
> + *   <FUNCTION>: 1
> + *
> + * @param device_path the path to the card
> + * @return the device address
> + */
> +std::string get_device_address(const std::string &card_path);
> +
> +}} // namespace spice::streaming_agent
> +
> +#endif // SPICE_STREAMING_AGENT_DISPLAY_INFO_HPP
> diff --git a/include/spice-streaming-agent/frame-capture.hpp
> b/include/spice-streaming-agent/frame-capture.hpp
> index 51a2987..c244fb9 100644
> --- a/include/spice-streaming-agent/frame-capture.hpp
> +++ b/include/spice-streaming-agent/frame-capture.hpp
> @@ -6,7 +6,11 @@
>   */
>  #ifndef SPICE_STREAMING_AGENT_FRAME_CAPTURE_HPP
>  #define SPICE_STREAMING_AGENT_FRAME_CAPTURE_HPP
> +
> +#include <cstdint>
>  #include <cstdio>
> +#include <string>
> +#include <vector>
>  
>  #include <spice/enums.h>
>  
> @@ -29,6 +33,13 @@ struct FrameInfo
>      bool stream_start;
>  };
>  
> +struct DeviceDisplayInfo
> +{
> +    uint32_t stream_id;
> +    std::string device_address;
> +    uint32_t device_display_id;
> +};
> +
>  /*!
>   * Pure base class implementing the frame capture
>   */
> @@ -52,6 +63,8 @@ public:
>       * Get video codec used to encode last frame
>       */
>      virtual SpiceVideoCodecType VideoCodecType() const = 0;
> +
> +    virtual std::vector<DeviceDisplayInfo> get_device_display_info()
> const = 0;
>  protected:
>      FrameCapture() = default;
>      FrameCapture(const FrameCapture&) = delete;
> diff --git a/include/spice-streaming-agent/x11-display-info.hpp
> b/include/spice-streaming-agent/x11-display-info.hpp
> new file mode 100644
> index 0000000..fa6afa7
> --- /dev/null
> +++ b/include/spice-streaming-agent/x11-display-info.hpp
> @@ -0,0 +1,57 @@
> +/* \copyright
> + * Copyright 2018 Red Hat Inc. All rights reserved.
> + */
> +
> +#ifndef SPICE_STREAMING_AGENT_X_DISPLAY_INFO_HPP
> +#define SPICE_STREAMING_AGENT_X_DISPLAY_INFO_HPP
> +
> +#include <spice-streaming-agent/frame-capture.hpp>
> +
> +#include <X11/Xlib.h>
> +
> +
> +namespace spice __attribute__ ((visibility ("default"))) {
> +namespace streaming_agent {
> +
> +/**
> + * Looks up device display info by listing the xrandr outputs of
> @display and
> + * comparing them to card output names found under the DRM subsystem
> in
> + * /sys/class/drm.
> + *
> + * Throws an Error in case of error or when the DRM outputs cannot
> be found.
> + *
> + * @param display the X display to find the info for
> + * @return a vector of DeviceDisplayInfo structs containing the
> information of
> + * all the outputs used by the display
> + */
> +std::vector<DeviceDisplayInfo> get_device_display_info_drm(Display
> *display);
> +
> +/**
> + * Attempts to get the device display info without using DRM. It
> looks up the
> + * first card in /sys/class/drm that doesn't have its outputs listed
> (assuming
> + * that if the card in use has DRM outputs, it would be found using
> the
> + * get_display_info function) and simply uses the xrandr output
> index as the
> + * device_display_id. This can obviously incorrectly match the
> device address
> + * and the device_display_ids of two unrelated devices.
> + *
> + * Unfortunately, without DRM, there is no way to match xrandr
> objects with the
> + * real device.
> + *
> + * @param display the X display to find the info for
> + * @return a vector of DeviceDisplayInfo structs containing the
> information of
> + * all the outputs used by the display
> + */
> +std::vector<DeviceDisplayInfo>
> get_device_display_info_no_drm(Display *display);
> +
> +/**
> + * Lists xrandr outputs and returns their names in a vector of
> strings.
> + *
> + * @param display the X display
> + * @param window the X root window
> + * @return A vector of xrandr output names
> + */
> +std::vector<std::string> get_xrandr_outputs(Display *display, Window
> window);
> +
> +}} // namespace spice::streaming_agent
> +
> +#endif // SPICE_STREAMING_AGENT_X_DISPLAY_INFO_HPP
> diff --git a/src/Makefile.am b/src/Makefile.am
> index bae3f9d..0133bf5 100644
> --- a/src/Makefile.am
> +++ b/src/Makefile.am
> @@ -16,9 +16,11 @@ AM_CPPFLAGS = \
>  	-DSPICE_STREAMING_AGENT_PROGRAM \
>  	-I$(top_srcdir)/include \
>  	-DPLUGINSDIR=\"$(pkglibdir)/plugins\" \
> +	$(DRM_CFLAGS) \
>  	$(SPICE_PROTOCOL_CFLAGS) \
>  	$(X11_CFLAGS) \
>  	$(XFIXES_CFLAGS) \
> +	$(XRANDR_CFLAGS) \
>  	$(NULL)
>  
>  AM_CFLAGS = \
> @@ -50,8 +52,10 @@ spice_streaming_agent_LDADD = \
>  	-ldl \
>  	-lpthread \
>  	libstreaming-utils.a \
> +	$(DRM_LIBS) \
>  	$(X11_LIBS) \
>  	$(XFIXES_LIBS) \
> +	$(XRANDR_LIBS) \
>  	$(JPEG_LIBS) \
>  	$(NULL)
>  
> @@ -61,6 +65,7 @@ spice_streaming_agent_SOURCES = \
>  	concrete-agent.hpp \
>  	cursor-updater.cpp \
>  	cursor-updater.hpp \
> +	display-info.cpp \
>  	frame-log.cpp \
>  	frame-log.hpp \
>  	mjpeg-fallback.cpp \
> @@ -69,7 +74,9 @@ spice_streaming_agent_SOURCES = \
>  	jpeg.hpp \
>  	stream-port.cpp \
>  	stream-port.hpp \
> +	utils.cpp \
>  	utils.hpp \
> +	x11-display-info.cpp \
>  	$(NULL)
>  
>  if HAVE_GST
> diff --git a/src/display-info.cpp b/src/display-info.cpp
> new file mode 100644
> index 0000000..469d587
> --- /dev/null
> +++ b/src/display-info.cpp
> @@ -0,0 +1,100 @@
> +/* \copyright
> + * Copyright 2018 Red Hat Inc. All rights reserved.
> + */
> +
> +#include <spice-streaming-agent/display-info.hpp>
> +
> +#include "utils.hpp"
> +#include <spice-streaming-agent/error.hpp>
> +
> +#include <algorithm>
> +#include <cstring>
> +#include <fstream>
> +#include <limits.h>
> +
> +
> +namespace spice {
> +namespace streaming_agent {
> +
> +namespace {
> +
> +std::string get_card_real_path(const std::string &card_path)
> +{
> +    char real_path_buf[PATH_MAX];
> +    if (realpath(card_path.c_str(), real_path_buf) == NULL) {
> +        throw Error("Failed to realpath \"" + card_path + "\": " +
> strerror(errno));

I thinik that realpath() technically needs <cstdlib>. Presumably it's
pulled it from somewhere else, but just for completeness...

> +    }
> +
> +    return real_path_buf;
> +}
> +
> +} // namespace
> +
> +std::vector<std::string> list_cards()
> +{
> +    std::string glob_path = "/sys/class/drm/card*";
> +    auto globs = utils::glob(glob_path);
> +
> +    globs.erase(std::remove_if(globs.begin(), globs.end(), [](const
> std::string &glob) {
> +            // if the path contains "-", it is an output, not a
> card, filter it out
> +            return glob.find("-") != glob.npos;
> +        }),
> +        globs.end()
> +    );
> +
> +    return globs;
> +}
> +
> +uint32_t read_hex_number_from_file(const std::string &path)
> +{
> +    uint32_t res;
> +    std::ifstream vf(path);
> +
> +    if (vf.fail()) {
> +        throw Error("Failed to open " + path + ": " +
> std::strerror(errno));
> +    }
> +
> +    if (!(vf >> std::hex >> res)) {
> +        throw Error("Failed to read from " + path + ": " +
> std::strerror(errno));
> +    }
> +
> +    return res;
> +}
> +
> +std::string get_device_address(const std::string &card_path)
> +{
> +    std::string real_path = get_card_real_path(card_path);
> +
> +    // real_path is e.g.
> /sys/devices/pci0000:00/0000:00:02.0/drm/card0
> +    std::string device_address = "pci/";
> +
> +    const std::string path_prefix = "/sys/devices/pci";
> +
> +    // if real_path doesn't start with path_prefix
> +    if (real_path.compare(0, path_prefix.length(), path_prefix)) {
> +        throw Error("Invalid device path \"" + real_path + "\"");
> +    }
> +
> +    // /sys/devices/pci0000:00/0000:00:02.0/drm/card0
> +    //                 ^ ptr
> +    const char *ptr = real_path.c_str() + path_prefix.length();
> +
> +    // copy the domain
> +    device_address += std::string(ptr, 4);
> +
> +    // /sys/devices/pci0000:00/0000:00:02.0/drm/card0
> +    //                        ^ ptr
> +    ptr += 7;
> +
> +    uint32_t domain, bus, slot, function, n;
> +    while (sscanf(ptr, "/%x:%x:%x.%x%n", &domain, &bus, &slot,
> &function, &n) == 4) {
> +        char pci_node[6];
> +        snprintf(pci_node, 6, "/%02x.%01x", slot, function);
> +        device_address += pci_node;
> +        ptr += n;
> +    }
> +
> +    return device_address;
> +}
> +
> +}} // namespace spice::streaming_agent
> diff --git a/src/gst-plugin.cpp b/src/gst-plugin.cpp
> index 097ef9d..3edf9f5 100644
> --- a/src/gst-plugin.cpp
> +++ b/src/gst-plugin.cpp
> @@ -23,6 +23,8 @@
>  
>  #include <spice-streaming-agent/plugin.hpp>
>  #include <spice-streaming-agent/frame-capture.hpp>
> +#include <spice-streaming-agent/x11-display-info.hpp>
> +
>  
>  #define gst_syslog(priority, str, ...) syslog(priority, "Gstreamer
> plugin: " str, ## __VA_ARGS__);
>  
> @@ -76,6 +78,7 @@ public:
>      SpiceVideoCodecType VideoCodecType() const override {
>          return settings.codec;
>      }
> +    std::vector<DeviceDisplayInfo> get_device_display_info() const
> override;
>  private:
>      void free_sample();
>      GstElement *get_encoder_plugin(const GstreamerEncoderSettings
> &settings, GstCapsUPtr &sink_caps);
> @@ -402,6 +405,17 @@ FrameInfo GstreamerFrameCapture::CaptureFrame()
>      return info;
>  }
>  
> +std::vector<DeviceDisplayInfo>
> GstreamerFrameCapture::get_device_display_info() const
> +{
> +    try {
> +        return get_device_display_info_drm(dpy);
> +    } catch (const std::exception &e) {
> +        syslog(LOG_WARNING, "Failed to get device info using DRM:
> %s. Using no-DRM fallback.",
> +               e.what());
> +        return get_device_display_info_no_drm(dpy);
> +    }
> +}
> +
>  FrameCapture *GstreamerPlugin::CreateCapture()
>  {
>      return new GstreamerFrameCapture(settings);
> diff --git a/src/mjpeg-fallback.cpp b/src/mjpeg-fallback.cpp
> index 8081007..09f3769 100644
> --- a/src/mjpeg-fallback.cpp
> +++ b/src/mjpeg-fallback.cpp
> @@ -7,6 +7,9 @@
>  #include <config.h>
>  #include "mjpeg-fallback.hpp"
>  
> +#include "jpeg.hpp"
> +#include <spice-streaming-agent/x11-display-info.hpp>
> +
>  #include <cstring>
>  #include <exception>
>  #include <stdexcept>
> @@ -15,8 +18,6 @@
>  #include <syslog.h>
>  #include <X11/Xlib.h>
>  
> -#include "jpeg.hpp"
> -
>  using namespace spice::streaming_agent;
>  
>  static inline uint64_t get_time()
> @@ -40,6 +41,7 @@ public:
>      SpiceVideoCodecType VideoCodecType() const override {
>          return SPICE_VIDEO_CODEC_TYPE_MJPEG;
>      }
> +    std::vector<DeviceDisplayInfo> get_device_display_info() const
> override;
>  private:
>      MjpegSettings settings;
>      Display *dpy;
> @@ -137,6 +139,17 @@ FrameInfo MjpegFrameCapture::CaptureFrame()
>      return info;
>  }
>  
> +std::vector<DeviceDisplayInfo>
> MjpegFrameCapture::get_device_display_info() const
> +{
> +    try {
> +        return get_device_display_info_drm(dpy);
> +    } catch (const std::exception &e) {
> +        syslog(LOG_WARNING, "Failed to get device info using DRM:
> %s. Using no-DRM fallback.",
> +               e.what());
> +        return get_device_display_info_no_drm(dpy);
> +    }
> +}
> +
>  FrameCapture *MjpegPlugin::CreateCapture()
>  {
>      return new MjpegFrameCapture(settings);
> diff --git a/src/spice-streaming-agent.cpp b/src/spice-streaming-
> agent.cpp
> index 1eb8e1b..3024d98 100644
> --- a/src/spice-streaming-agent.cpp
> +++ b/src/spice-streaming-agent.cpp
> @@ -217,6 +217,19 @@ do_capture(StreamPort &stream_port, FrameLog
> &frame_log)
>              throw std::runtime_error("cannot find a suitable capture
> system");
>          }
>  
> +        try {
> +            std::vector<DeviceDisplayInfo> display_info = capture-
> >get_device_display_info();
> +            syslog(LOG_DEBUG, "Got device info of %lu devices from
> the plugin", display_info.size());
> +            for (const auto &info : display_info) {
> +                syslog(LOG_DEBUG, "   id %u: device address %s,
> device display id: %u",
> +                       info.id,
> +                       info.device_address.c_str(),
> +                       info.device_display_id);
> +            }
> +        } catch (const Error &e) {
> +            syslog(LOG_ERR, "Error while getting device info: %s",
> e.what());
> +        }
> +
>          while (!quit_requested && streaming_requested) {
>              if (++frame_count % 100 == 0) {
>                  syslog(LOG_DEBUG, "SENT %d frames", frame_count);
> diff --git a/src/unittests/Makefile.am b/src/unittests/Makefile.am
> index 1ae5a07..8ce1f7a 100644
> --- a/src/unittests/Makefile.am
> +++ b/src/unittests/Makefile.am
> @@ -5,6 +5,7 @@ AM_CPPFLAGS = \
>  	-I$(top_srcdir)/include \
>  	-I$(top_srcdir)/src \
>  	-I$(top_srcdir)/src/unittests \
> +	$(DRM_CFLAGS) \
>  	$(SPICE_PROTOCOL_CFLAGS) \
>  	$(NULL)
>  
> @@ -43,13 +44,18 @@ hexdump_LDADD = \
>  
>  test_mjpeg_fallback_SOURCES = \
>  	test-mjpeg-fallback.cpp \
> +	../display-info.cpp \
>  	../jpeg.cpp \
>  	../mjpeg-fallback.cpp \
> +	../utils.cpp \
> +	../x11-display-info.cpp \
>  	$(NULL)
>  
>  test_mjpeg_fallback_LDADD = \
> +	$(DRM_LIBS) \
>  	$(X11_LIBS) \
>  	$(JPEG_LIBS) \
> +	$(XRANDR_LIBS) \
>  	$(NULL)
>  
>  test_stream_port_SOURCES = \
> diff --git a/src/utils.cpp b/src/utils.cpp
> new file mode 100644
> index 0000000..b78c893
> --- /dev/null
> +++ b/src/utils.cpp
> @@ -0,0 +1,46 @@
> +/* \copyright
> + * Copyright 2018 Red Hat Inc. All rights reserved.
> + */
> +
> +#include "utils.hpp"
> +
> +#include <spice-streaming-agent/error.hpp>
> +
> +#include <glob.h>
> +#include <string.h>
> +#include <stdexcept>
> +
> +
> +namespace spice {
> +namespace streaming_agent {
> +namespace utils {
> +
> +std::vector<std::string> glob(const std::string& pattern)
> +{
> +    glob_t glob_result{};
> +
> +    std::vector<std::string> filenames;
> +
> +    int ret = glob(pattern.c_str(), GLOB_ERR, NULL, &glob_result);
> +
> +    if(ret != 0) {
> +        globfree(&glob_result);
> +
> +        if (ret == GLOB_NOMATCH) {
> +            return filenames;
> +        }
> +
> +        throw Error("glob(" + pattern + ") failed with return value
> " + std::to_string(ret) +
> +                    ": " + strerror(errno));
> +    }
> +
> +    for(size_t i = 0; i < glob_result.gl_pathc; ++i) {
> +        filenames.push_back(glob_result.gl_pathv[i]);
> +    }
> +
> +    globfree(&glob_result);
> +
> +    return filenames;
> +}
> +
> +}}} // namespace spice::streaming_agent::utils
> diff --git a/src/utils.hpp b/src/utils.hpp
> index 64cb538..8c3b04e 100644
> --- a/src/utils.hpp
> +++ b/src/utils.hpp
> @@ -5,6 +5,8 @@
>  #ifndef SPICE_STREAMING_AGENT_UTILS_HPP
>  #define SPICE_STREAMING_AGENT_UTILS_HPP
>  
> +#include <vector>
> +#include <string>
>  #include <syslog.h>
>  
>  
> @@ -12,6 +14,8 @@ namespace spice {
>  namespace streaming_agent {
>  namespace utils {
>  
> +std::vector<std::string> glob(const std::string& pattern);
> +
>  template<class T>
>  const T &syslog(const T &error) noexcept
>  {
> diff --git a/src/x11-display-info.cpp b/src/x11-display-info.cpp
> new file mode 100644
> index 0000000..3890886
> --- /dev/null
> +++ b/src/x11-display-info.cpp
> @@ -0,0 +1,302 @@
> +/* \copyright
> + * Copyright 2018 Red Hat Inc. All rights reserved.
> + */
> +
> +#include <spice-streaming-agent/x11-display-info.hpp>
> +
> +#include <spice-streaming-agent/display-info.hpp>
> +#include "utils.hpp"
> +#include <spice-streaming-agent/error.hpp>
> +
> +#include <algorithm>
> +#include <cstring>
> +#include <map>
> +#include <fcntl.h>
> +#include <sys/stat.h>
> +#include <unistd.h>
> +#include <X11/extensions/Xrandr.h>
> +#include <xf86drm.h>
> +#include <xf86drmMode.h>
> +
> +
> +namespace spice {
> +namespace streaming_agent {
> +
> +namespace {
> +
> +constexpr uint32_t pci_vendor_id_redhat = 0x1b36;
> +constexpr uint32_t pci_device_id_qxl = 0x0100;
> +
> +struct OutputInfo {
> +    std::string output_name;
> +    std::string card_path;
> +    uint32_t card_vendor_id;
> +    uint32_t card_device_id;
> +    uint32_t device_display_id;
> +};
> +
> +static const std::map<uint32_t, std::string>
> modesetting_output_names = {
> +    {DRM_MODE_CONNECTOR_Unknown, "None"},
> +    {DRM_MODE_CONNECTOR_VGA, "VGA"},
> +    {DRM_MODE_CONNECTOR_DVII, "DVI-I"},
> +    {DRM_MODE_CONNECTOR_DVID, "DVI-D"},
> +    {DRM_MODE_CONNECTOR_DVIA, "DVI-A"},
> +    {DRM_MODE_CONNECTOR_Composite, "Composite"},
> +    {DRM_MODE_CONNECTOR_SVIDEO, "SVIDEO"},
> +    {DRM_MODE_CONNECTOR_LVDS, "LVDS"},
> +    {DRM_MODE_CONNECTOR_Component, "Component"},
> +    {DRM_MODE_CONNECTOR_9PinDIN, "DIN"},
> +    {DRM_MODE_CONNECTOR_DisplayPort, "DP"},
> +    {DRM_MODE_CONNECTOR_HDMIA, "HDMI"},
> +    {DRM_MODE_CONNECTOR_HDMIB, "HDMI-B"},
> +    {DRM_MODE_CONNECTOR_TV, "TV"},
> +    {DRM_MODE_CONNECTOR_eDP, "eDP"},
> +    {DRM_MODE_CONNECTOR_VIRTUAL, "Virtual"},
> +    {DRM_MODE_CONNECTOR_DSI, "DSI"},
> +    {DRM_MODE_CONNECTOR_DPI, "DPI"},
> +};
> +
> +// Connector type names from qxl driver
> +static const std::map<uint32_t, std::string> qxl_output_names = {
> +    {DRM_MODE_CONNECTOR_Unknown, "None"},
> +    {DRM_MODE_CONNECTOR_VGA, "VGA"},
> +    {DRM_MODE_CONNECTOR_DVII, "DVI"},
> +    {DRM_MODE_CONNECTOR_DVID, "DVI"},
> +    {DRM_MODE_CONNECTOR_DVIA, "DVI"},
> +    {DRM_MODE_CONNECTOR_Composite, "Composite"},
> +    {DRM_MODE_CONNECTOR_SVIDEO, "S-video"},
> +    {DRM_MODE_CONNECTOR_LVDS, "LVDS"},
> +    {DRM_MODE_CONNECTOR_Component, "CTV"},
> +    {DRM_MODE_CONNECTOR_9PinDIN, "DIN"},
> +    {DRM_MODE_CONNECTOR_DisplayPort, "DisplayPort"},
> +    {DRM_MODE_CONNECTOR_HDMIA, "HDMI"},
> +    {DRM_MODE_CONNECTOR_HDMIB, "HDMI"},
> +    {DRM_MODE_CONNECTOR_TV, "TV"},
> +    {DRM_MODE_CONNECTOR_eDP, "eDP"},
> +    {DRM_MODE_CONNECTOR_VIRTUAL, "Virtual"},
> +};
> +
> +std::string get_drm_name(const std::map<uint32_t, std::string>
> &name_map,
> +                         uint32_t connector_type,
> +                         uint32_t connector_type_id)
> +{
> +    auto name_it = name_map.find(connector_type);
> +    if (name_it == name_map.end()) {
> +        throw Error("Could not find DRM connector name for type " +
> std::to_string(connector_type));
> +    }
> +
> +    return name_it->second + "-" +
> std::to_string(connector_type_id);
> +}
> +
> +class DrmOutputGetter
> +{
> +public:
> +    DrmOutputGetter(const char* card_path)
> +    {
> +        drm_fd = open(card_path, O_RDWR);
> +        if (drm_fd < 0) {
> +            throw Error(std::string("Unable to open file %s: ") +
> strerror(errno));
> +        }
> +
> +        drm_resources = drmModeGetResources(drm_fd);
> +
> +        if (drm_resources == nullptr) {
> +            close(drm_fd);
> +            throw Error(std::string("Unable to get DRM resources for
> card ") + card_path);
> +        }
> +    }
> +
> +    ~DrmOutputGetter()
> +    {
> +        drmModeFreeResources(drm_resources);
> +        close(drm_fd);
> +    }
> +
> +    std::vector<std::string> get_output_names(const
> std::map<uint32_t, std::string> &names_map,
> +                                              bool decrement =
> false)
> +    {
> +        std::vector<std::string> result;
> +
> +        for (size_t i = 0; i < drm_resources->count_connectors; ++i)
> {
> +            drmModeConnectorPtr conn = drmModeGetConnector(drm_fd,
> drm_resources->connectors[i]);
> +
> +            if (conn == nullptr) {
> +                throw Error(std::string("Unable to get DRM
> connector: ") + strerror(errno));
> +            }
> +
> +            uint32_t cti = conn->connector_type_id;
> +            if (decrement) {
> +                cti--;
> +            }
> +            result.push_back(get_drm_name(names_map, conn-
> >connector_type, cti));
> +        }
> +
> +        return result;
> +    }
> +
> +private:
> +    int drm_fd = -1;
> +    drmModeResPtr drm_resources = nullptr;
> +};
> +
> +std::vector<OutputInfo> get_outputs()
> +{
> +    std::vector<OutputInfo> result;
> +
> +    for (uint8_t card_id = 0; card_id < 10; ++card_id) {
> +        std::string card_name = "card" + std::to_string(card_id);
> +
> +        char drm_path[64];
> +        snprintf(drm_path, sizeof(drm_path), DRM_DEV_NAME,
> DRM_DIR_NAME, card_id);
> +
> +        struct stat stat_buf;
> +        if (stat(drm_path, &stat_buf) != 0) {
> +            if (errno == ENOENT) {
> +                // we're done searching
> +                break;
> +            }
> +            throw Error(std::string("Error accessing DRM node for
> card ") + drm_path);
> +        }
> +
> +        std::string sys_path = "/sys/class/drm/" + card_name;
> +
> +        uint32_t vendor_id = read_hex_number_from_file(sys_path +
> "/device/vendor");
> +        uint32_t device_id = read_hex_number_from_file(sys_path +
> "/device/device");
> +
> +        std::vector<std::string> outputs;
> +
> +        if (vendor_id == pci_vendor_id_redhat && device_id ==
> pci_device_id_qxl) {
> +            // to find out whether QXL output names need
> decrementing, look for
> +            // an output called Virtual-0 in /sys/class/drm and if
> we find one,
> +            // decrement the number in the output names
> +            const auto globs = utils::glob("/sys/class/drm/card*-
> Virtual-0");
> +            outputs =
> DrmOutputGetter(drm_path).get_output_names(qxl_output_names,
> globs.size() > 0);
> +        } else {
> +            outputs =
> DrmOutputGetter(drm_path).get_output_names(modesetting_output_names);
> +        }
> +
> +        for (uint32_t i = 0; i < outputs.size(); ++i) {
> +            result.push_back({outputs[i],
> +                              sys_path,
> +                              vendor_id,
> +                              device_id,
> +                              i});
> +        }
> +    }
> +
> +    return result;
> +}
> +
> +} // namespace
> +
> +std::vector<std::string> get_xrandr_outputs(Display *display, Window
> window)
> +{
> +    XRRScreenResources *screen_resources =
> XRRGetScreenResources(display, window);
> +    std::vector<std::string> result;
> +    for (int i = 0; i < screen_resources->noutput; ++i) {
> +        XRROutputInfo *output_info = XRRGetOutputInfo(display,
> +                                                      screen_resourc
> es,
> +                                                      screen_resourc
> es->outputs[i]);
> +
> +        result.emplace_back(output_info->name);
> +
> +        XRRFreeOutputInfo(output_info);
> +    }
> +
> +    XRRFreeScreenResources(screen_resources);
> +    return result;
> +}
> +
> +std::vector<DeviceDisplayInfo> get_device_display_info_drm(Display
> *display)
> +{
> +    auto outputs = get_outputs();
> +
> +    // sorting by output name, may not be necessary (the list should
> be sorted out of glob)
> +    std::sort(outputs.begin(), outputs.end(), [](const OutputInfo
> &oi1, const OutputInfo &oi2) {
> +            return oi1.output_name > oi2.output_name;
> +        }
> +    );
> +
> +    // Check if the output names of QXL cards start at Virtual-1 and
> if so,
> +    // subtract one from each of them
> +    for (auto &output : outputs) {
> +        // if we find a QXL card
> +        if (output.card_vendor_id == pci_vendor_id_redhat &&
> +            output.card_device_id == pci_device_id_qxl)
> +        {
> +            // if the first name is Virtual-0, we know we are good,
> quit the loop
> +            if (output.output_name == "Virtual-0") {
> +                break;
> +            }
> +
> +            // if the name starts with "Virtual-"
> +            if (!output.output_name.compare(0, 8, "Virtual-")) {

I strongly prefer "foo.compare() == 0" over "!foo.compare()"

> +                // decrement the last digit by one
> +                // fails if the number at the end is more than one
> digit,
> +                // which would imply multiple QXL devices, an
> unsupported case
> +                output.output_name[output.output_name.length() - 1]-
> -;
> +            }
> +        }
> +    }
> +
> +    std::map<std::string, OutputInfo> output_map;
> +    for (const auto &output : outputs) {
> +        output_map[output.output_name] = output;
> +    }
> +
> +    auto xrandr_outputs = get_xrandr_outputs(display,
> RootWindow(display, XDefaultScreen(display)));
> +
> +    std::vector<DeviceDisplayInfo> result;
> +
> +    for (uint32_t i = 0; i < xrandr_outputs.size(); ++i) {
> +        const auto &output = xrandr_outputs[i];

Since you have variables named 'outputs' and 'xrandr_outputs' in this
function, I'd personally prefer to name this variable something like
'xoutput' instead of simply 'output' for clarity. 

> +        const auto it = output_map.find(output);
> +        if (it == output_map.end()) {
> +            throw Error("Could not find card for output " + output);
> +        }
> +
> +        std::string device_address = get_device_address(it-
> >second.card_path);
> +
> +        result.push_back({i, device_address, it-
> >second.device_display_id});
> +    }
> +
> +    return result;
> +}
> +
> +std::vector<DeviceDisplayInfo>
> get_device_display_info_no_drm(Display *display)
> +{
> +    // look for the first card that doesn't list its outputs (and
> therefore
> +    // doesn't support DRM), that's the best we can do...
> +    const auto globs = utils::glob("/sys/class/drm/card*");
> +
> +    std::string found_card_path;
> +    for (const auto &path : globs) {
> +        std::string card_output = path.substr(path.rfind("/") + 1,
> path.npos);
> +        auto dash_it = card_output.find("-");
> +        // if this file is a card (and not an output)
> +        if (dash_it == card_output.npos) {
> +            // if we already have a found card, this means it
> doesn't have any outputs,
> +            // we have found our card
> +            if (!found_card_path.empty()) {
> +                break;
> +            }
> +            found_card_path = card_output;
> +        } else {
> +            found_card_path = "";
> +        }
> +    }
> +
> +    std::string device_address =
> get_device_address(found_card_path);
> +
> +    auto xrandr_outputs = get_xrandr_outputs(display,
> RootWindow(display, XDefaultScreen(display)));
> +
> +    std::vector<DeviceDisplayInfo> result;
> +
> +    for (uint32_t i = 0; i < xrandr_outputs.size(); ++i) {
> +        result.push_back({i, device_address, i});
> +    }
> +
> +    return result;
> +}
> +
> +}} // namespace spice::streaming_agent


Acked-by: Jonathon Jongsma <jjongsma at redhat.com>




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