xfree86: Add MatchOS InputClass entry for operating system matching

Allow InputClass sections to match against the running operating system
to narrow the application of rules. An example where this could be used
is to specify that the default input driver on Linux is evdev while it's
mouse/kbd everywhere else.

The operating system name is the same as `uname -s`, and matching is
case-insensitive.

Signed-off-by: Dan Nicholson <dbn.lists@gmail.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Peter Hutterer <peter.hutterer@who-t.net>

configure.ac

@@ -123,7 +123,7 @@ AM_CONDITIONAL(SPECIAL_DTRACE_OBJECTS, [test "x$SPECIAL_DTRACE_OBJECTS" = "xyes"
 
 AC_HEADER_DIRENT
 AC_HEADER_STDC
-AC_CHECK_HEADERS([fcntl.h stdlib.h string.h unistd.h dlfcn.h stropts.h fnmatch.h])
+AC_CHECK_HEADERS([fcntl.h stdlib.h string.h unistd.h dlfcn.h stropts.h fnmatch.h sys/utsname.h])
 
 dnl Checks for typedefs, structures, and compiler characteristics.
 AC_C_CONST

hw/xfree86/common/xf86Xinput.c

@@ -80,6 +80,9 @@
 #ifdef HAVE_FNMATCH_H
 #include <fnmatch.h>
 #endif
+#ifdef HAVE_SYS_UTSNAME_H
+#include <sys/utsname.h>
+#endif
 
 #include "extnsionst.h"
 
@@ -496,6 +499,31 @@ AddOtherInputDevices(void)
 {
 }
 
+/*
+ * Get the operating system name from uname and store it statically to avoid
+ * repeating the system call each time MatchOS is checked.
+ */
+static const char *
+HostOS(void)
+{
+#ifdef HAVE_SYS_UTSNAME_H
+    struct utsname name;
+    static char host_os[sizeof(name.sysname)] = "";
+
+    if (*host_os == '\0') {
+        if (uname(&name) >= 0)
+            strcpy(host_os, name.sysname);
+        else {
+            strncpy(host_os, "unknown", sizeof(host_os));
+            host_os[sizeof(host_os)-1] = '\0';
+        }
+    }
+    return host_os;
+#else
+    return "";
+#endif
+}
+
 static int
 match_substring(const char *attr, const char *pattern)
 {
@@ -558,6 +586,10 @@ InputClassMatches(const XF86ConfInputClassPtr iclass,
     if (!MatchAttrToken(attrs->device, iclass->match_device, match_path_pattern))
         return FALSE;
 
+    /* MatchOS case-insensitive string */
+    if (!MatchAttrToken(HostOS(), iclass->match_os, strcasecmp))
+        return FALSE;
+
     /*
      * MatchTag string
      * See if any of the device's tags match any of the MatchTag tokens.

hw/xfree86/doc/man/xorg.conf.man.pre

@@ -1086,6 +1086,15 @@ This entry can be used to check if the device file matches the
 pathname pattern. Multiple patterns can be matched by separating arguments
 with a '|' character.
 .TP 7
+.BI "MatchOS \*q" matchos \*q
+This entry can be used to check if the operating system matches the
+case-insensitive
+.RI \*q matchos \*q
+string. This entry is only supported on platforms providing the
+.BR uname (2)
+system call. Multiple operating systems can be matched by separating arguments
+with a '|' character.
+.TP 7
 .BI "MatchTag \*q" matchtag \*q
 This entry can be used to check if tags assigned by the config backend
 matches the

hw/xfree86/parser/InputClass.c

@@ -47,6 +47,7 @@ xf86ConfigSymTabRec InputClassTab[] =
     {MATCH_PRODUCT, "matchproduct"},
     {MATCH_VENDOR, "matchvendor"},
     {MATCH_DEVICE_PATH, "matchdevicepath"},
+    {MATCH_OS, "matchos"},
     {MATCH_TAG, "matchtag"},
     {MATCH_IS_KEYBOARD, "matchiskeyboard"},
     {MATCH_IS_POINTER, "matchispointer"},
@@ -108,6 +109,11 @@ xf86parseInputClassSection(void)
                 Error(QUOTE_MSG, "MatchDevicePath");
             ptr->match_device = xstrtokenize(val.str, TOKEN_SEP);
             break;
+        case MATCH_OS:
+            if (xf86getSubToken(&(ptr->comment)) != STRING)
+                Error(QUOTE_MSG, "MatchOS");
+            ptr->match_os = xstrtokenize(val.str, TOKEN_SEP);
+            break;
         case MATCH_TAG:
             if (xf86getSubToken(&(ptr->comment)) != STRING)
                 Error(QUOTE_MSG, "MatchTag");
@@ -217,6 +223,14 @@ xf86printInputClassSection (FILE * cf, XF86ConfInputClassPtr ptr)
                         *list);
             fprintf(cf, "\"\n");
         }
+        if (ptr->match_os) {
+            fprintf(cf, "\tMatchOS         \"");
+            for (list = ptr->match_os; *list; list++)
+                fprintf(cf, "%s%s",
+                        list == ptr->match_os ? "" : TOKEN_SEP,
+                        *list);
+            fprintf(cf, "\"\n");
+        }
         if (ptr->match_tag) {
             fprintf(cf, "\tMatchTag \"");
             for (list = ptr->match_tag; *list; list++)
@@ -273,6 +287,11 @@ xf86freeInputClassList (XF86ConfInputClassPtr ptr)
                 free(*list);
             free(ptr->match_device);
         }
+        if (ptr->match_os) {
+            for (list = ptr->match_os; *list; list++)
+                free(*list);
+            free(ptr->match_os);
+        }
         if (ptr->match_tag) {
             for (list = ptr->match_tag; *list; list++)
                 free(*list);

hw/xfree86/parser/xf86Parser.h

@@ -346,6 +346,7 @@ typedef struct
 	char **match_product;
 	char **match_vendor;
 	char **match_device;
+	char **match_os;
 	char **match_tag;
 	xf86TriState is_keyboard;
 	xf86TriState is_pointer;

hw/xfree86/parser/xf86tokens.h

@@ -279,6 +279,7 @@ typedef enum {
     MATCH_PRODUCT,
     MATCH_VENDOR,
     MATCH_DEVICE_PATH,
+    MATCH_OS,
     MATCH_TAG,
     MATCH_IS_KEYBOARD,
     MATCH_IS_POINTER,

include/dix-config.h.in

@@ -222,6 +222,9 @@
 /* Define to 1 if you have the <sys/types.h> header file. */
 #undef HAVE_SYS_TYPES_H
 
+/* Define to 1 if you have the <sys/utsname.h> header file. */
+#undef HAVE_SYS_UTSNAME_H
+
 /* Define to 1 if you have the <sys/vm86.h> header file. */
 #undef HAVE_SYS_VM86_H