fastfetch/src/detection/displayserver/linux/displayserver_linux.c

#include "displayserver_linux.h"
#include "common/io/io.h"
#include "util/edidHelper.h"
#include "util/stringUtils.h"

#ifdef __FreeBSD__
    #include "common/settings.h"
#endif

void ffConnectDisplayServerImpl(FFDisplayServerResult* ds)
{
    if (instance.config.general.dsForceDrm == FF_DS_FORCE_DRM_TYPE_FALSE)
    {
        //We try wayland as our preferred display server, as it supports the most features.
        //This method can't detect the name of our WM / DE
        ffdsConnectWayland(ds);

        //Try the x11 libs, from most feature rich to least.
        //We use the display list to detect if a connection is needed.
        //They respect wmProtocolName, and only detect display if it is set.

        if(ds->displays.length == 0)
            ffdsConnectXcbRandr(ds);

        if(ds->displays.length == 0)
            ffdsConnectXrandr(ds);

        if(ds->displays.length == 0)
            ffdsConnectXcb(ds);

        if(ds->displays.length == 0)
            ffdsConnectXlib(ds);
    }

    //This display detection method is display server independent.
    //Use it if all connections failed
    if(ds->displays.length == 0)
        ffdsConnectDrm(ds);

    #ifdef __FreeBSD__
    if(ds->displays.length == 0)
    {
        FF_STRBUF_AUTO_DESTROY buf = ffStrbufCreate();
        if (ffSettingsGetFreeBSDKenv("screen.width", &buf))
        {
            uint32_t width = (uint32_t) ffStrbufToUInt(&buf, 0);
            if (width)
            {
                ffStrbufClear(&buf);
                if (ffSettingsGetFreeBSDKenv("screen.height", &buf))
                {
                    uint32_t height = (uint32_t) ffStrbufToUInt(&buf, 0);
                    ffdsAppendDisplay(ds, width, height, 0, 0, 0, 0, NULL, FF_DISPLAY_TYPE_UNKNOWN, false, 0);
                }
            }
        }
    }
    #endif

    //This fills in missing information about WM / DE by using env vars and iterating processes
    ffdsDetectWMDE(ds);
}

bool ffdsMatchDrmConnector(const char* connName, FFstrbuf* edidName)
{
    // https://wayland.freedesktop.org/docs/html/apa.html#protocol-spec-wl_output-event-name
    // The doc says that "do not assume that the name is a reflection of an underlying DRM connector, X11 connection, etc."
    // However I can't find a better method to get the edid data
    const char* drmDirPath = "/sys/class/drm/";

    DIR* dirp = opendir(drmDirPath);
    if(dirp == NULL)
        return false;

    struct dirent* entry;
    while((entry = readdir(dirp)) != NULL)
    {
        const char* plainName = entry->d_name;
        if (ffStrStartsWith(plainName, "card"))
        {
            const char* tmp = strchr(plainName + strlen("card"), '-');
            if (tmp) plainName = tmp + 1;
        }
        if (ffStrEquals(plainName, connName))
        {
            ffStrbufAppendF(edidName, "%s%s/edid", drmDirPath, entry->d_name);

            uint8_t edidData[128];
            if(ffReadFileData(edidName->chars, sizeof(edidData), edidData) == sizeof(edidData))
            {
                ffStrbufClear(edidName);
                ffEdidGetName(edidData, edidName);
                closedir(dirp);
                return true;
            }
            break;
        }
    }
    ffStrbufClear(edidName);
    closedir(dirp);
    return false;
}