Use spawnl() rather than pipe() & fork() to invoke xkbcomp

Implement System() specially on Cygwin not to use fork() and exec(), but
spawnl()

Use System() and a temp file rather than pipe() & fork() to invoke xkbcomp
on cygwin, just as done on mingw

Somewhat the counsel of despair, but sometimes Windows is being such a
little bitch that the cygwin DLL just can't emulate fork() successfully,
so just using spawnl() here is more robust and means I don't have to deal
with end-users reporting this as a problem with the xserver

Signed-off-by: Jon TURNEY <jon.turney@dronecode.org.uk>

3 files changed, 57 insertions, 14 deletions

diff --git a/os/utils.c b/os/utils.c
index 945094c03..74b1199ca 100644
--- a/os/utils.c
+++ b/os/utils.c
@@ -1262,6 +1262,25 @@ OsAbort (void)
  * as well.  As it is now, xkbcomp messages don't end up in the log file.
  */
 
+#ifdef __CYGWIN__
+#include <process.h>
+int
+System(const char *command)
+{
+    int status;
+    if (!command)
+	return 1;
+
+    DebugF("System: `%s'\n", command);
+
+    /*
+      Use spawnl() rather than execl() to implement System() on cygwin to
+      avoid fork emulation overhead and brittleness
+    */
+    status = spawnl(_P_WAIT, "/bin/sh", "sh", "-c", command, (char *)NULL);
+    return status;
+}
+#else
 int
 System(const char *command)
 {
@@ -1303,6 +1322,7 @@ System(const char *command)
 
     return p == -1 ? -1 : status;
 }
+#endif
 
 static struct pid {
     struct pid *next;
@@ -1312,6 +1332,7 @@ static struct pid {
 
 OsSigHandlerPtr old_alarm = NULL; /* XXX horrible awful hack */
 
+#if !defined(__CYGWIN__)
 pointer
 Popen(const char *command, const char *type)
 {
@@ -1396,6 +1417,7 @@ Popen(const char *command, const char *type)
 
     return iop;
 }
+#endif
 
 /* fopen that drops privileges */
 pointer
diff --git a/xkb/ddxList.c b/xkb/ddxList.c
index db34c8df5..0164e2159 100644
--- a/xkb/ddxList.c
+++ b/xkb/ddxList.c
@@ -58,6 +58,16 @@ extern int Win32System(const char *cmdline);
 #define W32_tmplen 0
 #endif 
 
+#ifdef __CYGWIN__
+extern const char* Win32TempDir(void);
+#endif
+
+#if defined(WIN32)
+#define PATHSEPARATOR "\\"
+#else
+#define PATHSEPARATOR "/"
+#endif
+
 /***====================================================================***/
 
 static const char *componentDirs[_XkbListNumComponents] = {
@@ -127,7 +137,7 @@ char 	*file,*map,*tmp,*buf=NULL;
 FILE 	*in;
 Status	status;
 Bool	haveDir;
-#ifdef WIN32
+#if defined(WIN32) || defined(__CYGWIN__)
 char	tmpname[PATH_MAX];
 #else
 int	rval;
@@ -149,9 +159,9 @@ int	rval;
 
     in= NULL;
     haveDir= TRUE;
-#ifdef WIN32
+#if defined(WIN32) || defined(__CYGWIN__)
     strcpy(tmpname, Win32TempDir());
-    strcat(tmpname, "\\xkb_XXXXXX");
+    strcat(tmpname, PATHSEPARATOR "xkb_XXXXXX");
     (void) mktemp(tmpname);
 #endif
     if (XkbBaseDirectory!=NULL) {
@@ -200,7 +210,7 @@ int	rval;
     status= Success;
     if (!haveDir)
     {  
-#ifndef WIN32
+#if !defined(WIN32) && !defined(__CYGWIN__)
 	in= Popen(buf,"r");
 #else
         if (xkbDebugFlags)
@@ -214,7 +224,7 @@ int	rval;
     if (!in)
     {
 	free(buf);
-#ifdef WIN32
+#if defined(WIN32) || defined(__CYGWIN__)
 	unlink(tmpname);
 #endif
 	return BadImplementation;
@@ -224,7 +234,7 @@ int	rval;
     buf = malloc(PATH_MAX * sizeof(char));
     if (!buf) {
         fclose(in);
-#ifdef WIN32
+#if defined(WIN32) || defined(__CYGWIN__)
         unlink(tmpname);
 #endif
         return BadAlloc;
@@ -270,7 +280,7 @@ int	rval;
 	}
 	status= _AddListComponent(list,what,flags,tmp,client);
     }
-#ifndef WIN32
+#if !defined(WIN32) && !defined(__CYGWIN__)
     if (haveDir)
 	fclose(in);
     else if ((rval=Pclose(in))!=0) {
diff --git a/xkb/ddxLoad.c b/xkb/ddxLoad.c
index 196142318..0d88b7f34 100644
--- a/xkb/ddxLoad.c
+++ b/xkb/ddxLoad.c
@@ -144,6 +144,17 @@ Win32System(const char *cmdline)
 }
 #undef System
 #define System(x) Win32System(x)
+#elif defined(__CYGWIN__)
+const char*
+Win32TempDir(void)
+{
+    if (getenv("TEMP") != NULL)
+        return getenv("TEMP");
+    else if (getenv("TMP") != NULL)
+        return getenv("TEMP");
+    else
+        return "/tmp";
+}
 #endif
 
 static void
@@ -186,7 +197,7 @@ XkbDDXCompileKeymapByNames(	XkbDescPtr		xkb,
     const char	*xkbbindir = emptystring;
     const char	*xkbbindirsep = emptystring;
 
-#ifdef WIN32
+#if defined(WIN32) || defined(__CYGWIN__)
     /* WIN32 has no popen. The input must be stored in a file which is
        used as input for xkbcomp. xkbcomp does not read from stdin. */
     char tmpname[PATH_MAX];
@@ -199,9 +210,9 @@ XkbDDXCompileKeymapByNames(	XkbDescPtr		xkb,
 
     OutputDirectory(xkm_output_dir, sizeof(xkm_output_dir));
 
-#ifdef WIN32
+#if defined(WIN32) || defined(__CYGWIN__)
     strcpy(tmpname, Win32TempDir());
-    strcat(tmpname, "\\xkb_XXXXXX");
+    strcat(tmpname, PATHSEPARATOR "xkb_XXXXXX");
     (void) mktemp(tmpname);
 #endif
 
@@ -240,7 +251,7 @@ XkbDDXCompileKeymapByNames(	XkbDescPtr		xkb,
         return FALSE;
     }
     
-#ifndef WIN32
+#if !defined(WIN32) && !defined(__CYGWIN__)
     out= Popen(buf,"w");
 #else
     out= fopen(tmpname, "w");
@@ -254,7 +265,7 @@ XkbDDXCompileKeymapByNames(	XkbDescPtr		xkb,
     }
 #endif
 	XkbWriteXKBKeymapForNames(out,names,xkb,want,need);
-#ifndef WIN32
+#if !defined(WIN32) && !defined(__CYGWIN__)
 	if (Pclose(out)==0)
 #else
 	if (fclose(out)==0 && System(buf) >= 0)
@@ -266,14 +277,14 @@ XkbDDXCompileKeymapByNames(	XkbDescPtr		xkb,
 		strlcpy(nameRtrn,keymap,nameRtrnLen);
 	    }
             free(buf);
-#ifdef WIN32
+#if defined(WIN32) || defined(__CYGWIN__)
 	    unlink(tmpname);
 #endif
 	    return TRUE;
 	}
 	else
 	    LogMessage(X_ERROR, "Error compiling keymap (%s)\n", keymap);
-#ifdef WIN32
+#if defined(WIN32) || defined(__CYGWIN__)
         /* remove the temporary file */
         unlink(tmpname);
 #endif