fix shm_open wrongly being cancellable

src/mman/shm_open.c

@@ -4,6 +4,7 @@
 #include <unistd.h>
 #include <string.h>
 #include <limits.h>
+#include <pthread.h>
 
 char *__strchrnul(const char *, int);
 
@@ -27,9 +28,13 @@ char *__shm_mapname(const char *name, char *buf)
 
 int shm_open(const char *name, int flag, mode_t mode)
 {
+	int cs;
 	char buf[NAME_MAX+10];
 	if (!(name = __shm_mapname(name, buf))) return -1;
-	return open(name, flag|O_NOFOLLOW|O_CLOEXEC|O_NONBLOCK, mode);
+	pthread_setcancelstate(PTHREAD_CANCEL_DISABLE, &cs);
+	int fd = open(name, flag|O_NOFOLLOW|O_CLOEXEC|O_NONBLOCK, mode);
+	pthread_setcancelstate(cs, 0);
+	return fd;
 }
 
 int shm_unlink(const char *name)