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4614834: Xlib color functions are not MT-safe
In a multithreaded Xlib client:
* concurrent access to XAllocNamedColor() make the client crash
* concurrent access to XLookupColor() make the client crash
The cause of the problem is that in multithread environment some data
in XLookupColor() and XAllocNamedColor() can be accessed/modified at
same time by multi threads. Adding some lock and unlock code to make
sure only one thread can access the data at one time fixed the
problem.
diff --git a/src/GetColor.c b/src/GetColor.c
index cd0eb9f..62b3bce 100644
--- a/src/GetColor.c
+++ b/src/GetColor.c
@@ -55,12 +55,14 @@ XColor *exact_def) /* RETURN */
if ((ccc = XcmsCCCOfColormap(dpy, cmap)) != (XcmsCCC)NULL) {
const char *tmpName = colorname;
+ LockDisplay(dpy);
switch (_XcmsResolveColorString(ccc, &tmpName, &cmsColor_exact,
XcmsRGBFormat)) {
case XcmsSuccess:
case XcmsSuccessWithCompression:
_XcmsRGB_to_XColor(&cmsColor_exact, exact_def, 1);
memcpy((char *)hard_def, (char *)exact_def, sizeof(XColor));
+ UnlockDisplay(dpy);
ret = XAllocColor(dpy, cmap, hard_def);
exact_def->pixel = hard_def->pixel;
return(ret);
@@ -73,6 +75,7 @@ XColor *exact_def) /* RETURN */
*/
break;
}
+ UnlockDisplay(dpy);
}
#endif
diff --git a/src/LookupCol.c b/src/LookupCol.c
index f7f969f..718e043 100644
@@ -53,6 +53,7 @@ XLookupColor (
if ((ccc = XcmsCCCOfColormap(dpy, cmap)) != (XcmsCCC)NULL) {
const char *tmpName = spec;
+ LockDisplay(dpy);
switch (_XcmsResolveColorString(ccc, &tmpName, &cmsColor_exact,
XcmsRGBFormat)) {
case XcmsSuccess:
@@ -60,6 +61,7 @@ XLookupColor (
_XcmsRGB_to_XColor(&cmsColor_exact, def, 1);
memcpy((char *)scr, (char *)def, sizeof(XColor));
_XUnresolveColor(ccc, scr);
+ UnlockDisplay(dpy);
return(1);
case XcmsFailure:
case _XCMS_NEWNAME:
@@ -70,6 +72,7 @@ XLookupColor (
*/
break;
}
+ UnlockDisplay(dpy);
}
#endif