xfree86: Add ModulePath support for OutputClass config Sections

Allow OutputClass config snippets to modify the module-path.

Note that any specified ModulePaths will be pre-pended to the normal
ModulePath. The idea behind this is that any output hardware specific
modules should have preference over the normal modules.

One use-case for this is the nvidia binary driver, this allows a
config snippet like this:

Section "OutputClass"
    MatchDriver "nvidia"
    Modulepath "/usr/lib64/nvidia/modules"
EndSection

To get the nvidia glx specific glx module loaded, but only when the
nvidia kernel driver is loaded.

Together with the glvnd work done recently, this allows the nouveau
+ mesa and nvidia-binary userspace stacks to co-exist on the same
system without any ldconfig / xorg.conf tweaking and the xserver will
automatically do the right thing depending on which kernel driver
(nouveau or nvidia) is loaded.

Reviewed-by: Adam Jackson <ajax@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>

hw/xfree86/common/xf86platformBus.c

@@ -40,6 +40,7 @@
 #include "hotplug.h"
 #include "systemd-logind.h"
 
+#include "loaderProcs.h"
 #include "xf86.h"
 #include "xf86_OSproc.h"
 #include "xf86Priv.h"
@@ -287,6 +288,7 @@ xf86platformProbe(void)
     int i;
     Bool pci = TRUE;
     XF86ConfOutputClassPtr cl;
+    char *old_path, *path = NULL;
 
     config_odev_probe(xf86PlatformDeviceProbe);
 
@@ -300,8 +302,29 @@ xf86platformProbe(void)
         if (pci && (strncmp(busid, "pci:", 4) == 0)) {
             platform_find_pci_info(&xf86_platform_devices[i], busid);
         }
+
+        /*
+         * Deal with OutputClass ModulePath directives, these must be
+         * processed before we do any module loading.
+         */
+        for (cl = xf86configptr->conf_outputclass_lst; cl; cl = cl->list.next) {
+            if (!OutputClassMatches(cl, &xf86_platform_devices[i]))
+                continue;
+
+            if (cl->modulepath && xf86ModPathFrom != X_CMDLINE) {
+                old_path = path;
+                XNFasprintf(&path, "%s,%s", cl->modulepath,
+                            path ? path : xf86ModulePath);
+                free(old_path);
+                xf86Msg(X_CONFIG, "OutputClass \"%s\" ModulePath extended to \"%s\"\n",
+                        cl->identifier, path);
+                LoaderSetPath(path);
+            }
+        }
     }
 
+    free(path);
+
     /* First see if there is an OutputClass match marking a device as primary */
     for (i = 0; i < xf86_num_platform_devices; i++) {
         struct xf86_platform_device *dev = &xf86_platform_devices[i];

hw/xfree86/loader/loadmod.c

@@ -184,6 +184,7 @@ LoaderSetPath(const char *path)
     if (!path)
         return;
 
+    FreeStringList(defaultPathList);
     defaultPathList = InitPathList(path);
 }
 

hw/xfree86/man/xorg.conf.man

@@ -1300,6 +1300,22 @@ This option specifies that the matched device should be treated as the
 primary GPU, replacing the selection of the GPU used as output by the
 firmware. If multiple output devices match an OutputClass section with
 the PrimaryGPU option set, the first one enumerated becomes the primary GPU.
+.PP
+A
+.B OutputClass
+Section may contain
+.B ModulePath
+entries. When an output device matches an
+.B OutputClass
+section, any
+.B ModulePath
+entries in that
+.B OutputClass
+are pre-pended to the search path for loadable Xorg server modules. See
+.B ModulePath
+in the
+.B Files
+section for more info.
 .SH "DEVICE SECTION"
 The config file may have multiple
 .B Device

hw/xfree86/parser/OutputClass.c

@@ -36,6 +36,7 @@ static const xf86ConfigSymTabRec OutputClassTab[] = {
     {ENDSECTION, "endsection"},
     {IDENTIFIER, "identifier"},
     {DRIVER, "driver"},
+    {MODULEPATH, "modulepath"},
     {OPTION, "option"},
     {MATCH_DRIVER, "matchdriver"},
     {-1, ""},
@@ -53,6 +54,7 @@ xf86freeOutputClassList(XF86ConfOutputClassPtr ptr)
         TestFree(ptr->identifier);
         TestFree(ptr->comment);
         TestFree(ptr->driver);
+        TestFree(ptr->modulepath);
 
         xorg_list_for_each_entry_safe(group, next, &ptr->match_driver, entry) {
             xorg_list_del(&group->entry);
@@ -115,6 +117,19 @@ xf86parseOutputClassSection(void)
             else
                 ptr->driver = xf86_lex_val.str;
             break;
+        case MODULEPATH:
+            if (xf86getSubToken(&(ptr->comment)) != STRING)
+                Error(QUOTE_MSG, "ModulePath");
+            if (ptr->modulepath) {
+                char *path;
+                XNFasprintf(&path, "%s,%s", ptr->modulepath, xf86_lex_val.str);
+                free(xf86_lex_val.str);
+                free(ptr->modulepath);
+                ptr->modulepath = path;
+            } else {
+                ptr->modulepath = xf86_lex_val.str;
+            }
+            break;
         case OPTION:
             ptr->option_lst = xf86parseOption(ptr->option_lst);
             break;

hw/xfree86/parser/xf86Parser.h

@@ -337,6 +337,7 @@ typedef struct {
     GenericListRec list;
     char *identifier;
     char *driver;
+    char *modulepath;
     struct xorg_list match_driver;
     XF86OptionPtr option_lst;
     char *comment;