--- ray/src/rt/RdataShareMap.cpp	2024/10/29 00:36:54	2.1
+++ ray/src/rt/RdataShareMap.cpp	2025/03/20 17:59:10	2.4
@@ -1,5 +1,5 @@
 #ifndef lint
-static const char RCSid[] = "$Id: RdataShareMap.cpp,v 2.1 2024/10/29 00:36:54 greg Exp $";
+static const char RCSid[] = "$Id: RdataShareMap.cpp,v 2.4 2025/03/20 17:59:10 greg Exp $";
 #endif
 /*
  *  RdataShareMap.cpp
@@ -36,25 +36,24 @@ RdataShareMap::RdataShareMap(const char *name, int fla
 		error(CONSISTENCY, "bad RDSextend in RdataShareMap()");
 		return;
 	}
-	int	mmprot = PROT_NONE;
-	int	oflags = 0;
+	int	oflags, mmprot;
 	switch (flags & (RDSread|RDSwrite)) {
 	case RDSread|RDSwrite:
-		mmprot |= PROT_READ|PROT_WRITE;
-		oflags |= O_RDWR;
+		mmprot = PROT_READ|PROT_WRITE;
+		oflags = O_RDWR|O_CREAT;
 		break;
-	case RDSread:
-		mmprot |= PROT_READ;
-		oflags |= O_RDONLY;
-		break;
 	case RDSwrite:
-		mmprot |= PROT_WRITE;
-		oflags |= O_WRONLY;
+		mmprot = PROT_WRITE;
+		oflags = O_RDWR|O_CREAT;	// XXX system limitation
 		break;
+	case RDSread:
+		mmprot = PROT_READ;
+		oflags = O_RDONLY;
+		break;
 	}
 	int	fd = -1;
 	if (name) {			// opening a shared file
-		if (flags & RDSexcl) oflags |= O_CREAT|O_EXCL;
+		if (flags & RDSexcl) oflags |= O_EXCL;
 		else if (flags & RDSextend && !siz) oflags |= O_TRUNC;
 		fd = open(name, oflags, 0666);
 		if (fd < 0) {
@@ -69,7 +68,7 @@ RdataShareMap::RdataShareMap(const char *name, int fla
 			else if (fstat(fd, &sbuf) >= 0)
 				siz = sbuf.st_size;
 			else {
-				sprintf(errmsg, "cannot stat '%s'", chName);
+				sprintf(errmsg, "cannot stat '%s'", name);
 				error(SYSTEM, errmsg);
 				close(fd);
 				return;
@@ -81,7 +80,7 @@ RdataShareMap::RdataShareMap(const char *name, int fla
 			return;
 		}
 	}
-	mmorg = (void *)mmap(NULL, siz, mmprot,
+	if (siz) mmorg = (void *)mmap(NULL, siz, mmprot,
 				MAP_SHARED|(name ? MAP_FILE : MAP_ANON), fd, 0);
 	close(fd);
 	if (mmorg == MAP_FAILED) {
@@ -108,8 +107,6 @@ RdataShareMap::~RdataShareMap()
 size_t
 RdataShareMap::Resize(size_t new_siz)
 {
-	if (!mmorg)
-		return 0;
 	if (new_siz > 0) {
 		if (new_siz == osiz)
 			return osiz;
@@ -156,7 +153,7 @@ RdataShareMap::Resize(size_t new_siz)
 			close(fd);
 			return 0;
 		}
-		munmap(mmorg, osiz);
+		if (mmorg) munmap(mmorg, osiz);
 		mmorg = mmap(NULL, new_siz,
 				mode&RDSread ? PROT_READ|PROT_WRITE : PROT_WRITE,
 				MAP_SHARED|MAP_FILE, fd, 0);