Non-root Xorg на Intel'е

$ eix xorg-server

Установленные версии:  1.19.5-r1(17:25:37 17.03.2018)(glamor udev xorg -debug -dmx -doc
-ipv6 -kdrive -libressl -minimal -selinux -static-libs -suid -systemd -tslib -unwind
-wayland -xcsecurity -xephyr -xnest -xvfb)

ret = drmSetMaster(ms->fd);
if (ret)
    xf86DrvMsg(pScrn->scrnIndex, X_ERROR, "drmSetMaster failed: %s\n", ...

diff --git hw/xfree86/drivers/modesetting/driver.c hw/xfree86/drivers/modesetting/driver.c
index 4d5c4e3..afc411c 100644
--- hw/xfree86/drivers/modesetting/driver.c
+++ hw/xfree86/drivers/modesetting/driver.c
@@ -34,7 +34,12 @@
 #endif
 
 #include <unistd.h>
+#include <stdio.h>
 #include <fcntl.h>
+#include <sys/wait.h>
+#include <pthread.h>
+#include <sys/socket.h>
+#include <sys/un.h>
 #include "xf86.h"
 #include "xf86_OSproc.h"
 #include "compiler.h"
@@ -62,6 +67,8 @@
 #include "driver.h"
 #include "sh3224.h"
 
+#define DRM_HACK_SOCKET_NAME "xorg_drm_master_util"
+
 static void AdjustFrame(ScrnInfoPtr pScrn, int x, int y);
 static Bool CloseScreen(ScreenPtr pScreen);
 static Bool EnterVT(ScrnInfoPtr pScrn);
@@ -1495,11 +1502,66 @@ msSharedPixmapNotifyDamage(PixmapPtr ppix)
     return ret;
 }
 
+static int
+send_fd(int sock, int fd)
+{
+    // This function does the arcane magic for sending
+    // file descriptors over unix domain sockets
+    struct msghdr msg;
+    struct iovec iov[1];
+    struct cmsghdr *cmsg = NULL;
+    char ctrl_buf[CMSG_SPACE(sizeof(int))];
+    char data[1];
+
+    memset(&msg, 0, sizeof(struct msghdr));
+    memset(ctrl_buf, 0, CMSG_SPACE(sizeof(int)));
+
+    data[0] = ' ';
+    iov[0].iov_base = data;
+    iov[0].iov_len = sizeof(data);
+
+    msg.msg_name = NULL;
+    msg.msg_namelen = 0;
+    msg.msg_iov = iov;
+    msg.msg_iovlen = 1;
+    msg.msg_controllen =  CMSG_SPACE(sizeof(int));
+    msg.msg_control = ctrl_buf;
+
+    cmsg = CMSG_FIRSTHDR(&msg);
+    cmsg->cmsg_level = SOL_SOCKET;
+    cmsg->cmsg_type = SCM_RIGHTS;
+    cmsg->cmsg_len = CMSG_LEN(sizeof(int));
+
+    *((int *) CMSG_DATA(cmsg)) = fd;
+
+    return sendmsg(sock, &msg, 0);
+}
+
+static void*
+thread_func(void* argument)
+{
+    int ret;
+    int option = *(int *)argument;
+    char cmd[32];
+    sprintf(cmd, "/usr/bin/drm_master_util %s -r", (!option ? "-s" : "-d"));
+
+    ret = system(cmd);
+    if (ret == -1 || WEXITSTATUS(ret) != 0) {
+        fprintf(stderr, "%s\n", strerror(errno));
+        //exit(1);
+    }
+
+    pthread_exit(NULL); // you could also return NULL here to exit no difference
+}
+
 static Bool
 SetMaster(ScrnInfoPtr pScrn)
 {
     modesettingPtr ms = modesettingPTR(pScrn);
-    int ret;
+    int ret = 0;
+    pthread_t my_thread;
+    struct sockaddr_un addr;
+    int sock, conn, option = 0;
 
 #ifdef XF86_PDEV_SERVER_FD
     if (ms->pEnt->location.type == BUS_PLATFORM &&
@@ -1507,10 +1569,25 @@ SetMaster(ScrnInfoPtr pScrn)
         return TRUE;
 #endif
 
-    ret = drmSetMaster(ms->fd);
-    if (ret)
+    sock = socket(AF_UNIX, SOCK_STREAM, 0);
+    memset(&addr, 0, sizeof(addr));
+    addr.sun_family = AF_UNIX;
+    strcpy(&addr.sun_path[1], DRM_HACK_SOCKET_NAME);
+    bind(sock, (struct sockaddr *)&addr, sizeof(addr));
+
+    listen(sock, 1);
+    pthread_create(&my_thread, NULL, thread_func, &option);
+
+    conn = accept(sock, NULL, 0);
+    send_fd(conn, ms->fd);
+    close(conn);
+    close(sock);
+
+    pthread_join(my_thread, NULL);
+
+    /*if (ret == -1 || WEXITSTATUS(ret) != 0)
         xf86DrvMsg(pScrn->scrnIndex, X_ERROR, "drmSetMaster failed: %s\n",
-                   strerror(errno));
+                   strerror(errno));*/
 
     return ret == 0;
 }
@@ -1749,6 +1826,9 @@ static void
 LeaveVT(ScrnInfoPtr pScrn)
 {
     modesettingPtr ms = modesettingPTR(pScrn);
+    pthread_t my_thread;
+    struct sockaddr_un addr;
+    int sock, conn, option = 1;
 
     xf86_hide_cursors(pScrn);
 
@@ -1760,7 +1840,21 @@ LeaveVT(ScrnInfoPtr pScrn)
         return;
 #endif
 
-    drmDropMaster(ms->fd);
+    sock = socket(AF_UNIX, SOCK_STREAM, 0);
+    memset(&addr, 0, sizeof(addr));
+    addr.sun_family = AF_UNIX;
+    strcpy(&addr.sun_path[1], DRM_HACK_SOCKET_NAME);
+    bind(sock, (struct sockaddr *)&addr, sizeof(addr));
+
+    listen(sock, 1);
+    pthread_create(&my_thread, NULL, thread_func, &option);
+
+    conn = accept(sock, NULL, 0);
+    send_fd(conn, ms->fd);
+    close(conn);
+    close(sock);
+
+    pthread_join(my_thread, NULL);
 }
 
 /*