1 files changed, 27 insertions, 7 deletions

diff --git a/cursor/os-compatibility.c b/cursor/os-compatibility.c
index 8d51e52..f2445ce 100644
--- a/cursor/os-compatibility.c
+++ b/cursor/os-compatibility.c
@@ -31,7 +31,9 @@
 #include <unistd.h>
 #include <fcntl.h>
 #include <errno.h>
+#include <signal.h>
 #include <string.h>
+#include <stdio.h>
 #include <stdlib.h>
 
 #ifdef HAVE_MEMFD_CREATE
@@ -118,6 +120,7 @@ os_create_anonymous_file(off_t size)
 	static const char template[] = "/wayland-cursor-shared-XXXXXX";
 	const char *path;
 	char *name;
+	size_t name_size;
 	int fd;
 
 #ifdef HAVE_MEMFD_CREATE
@@ -134,17 +137,17 @@ os_create_anonymous_file(off_t size)
 #endif
 	{
 		path = getenv("XDG_RUNTIME_DIR");
-		if (!path) {
+		if (!path || path[0] != '/') {
 			errno = ENOENT;
 			return -1;
 		}
 
-		name = malloc(strlen(path) + sizeof(template));
+		name_size = strlen(path) + sizeof(template);
+		name = malloc(name_size);
 		if (!name)
 			return -1;
 
-		strcpy(name, path);
-		strcat(name, template);
+		snprintf(name, name_size, "%s%s", path, template);
 
 		fd = create_tmpfile_cloexec(name);
 
@@ -166,11 +169,28 @@ int
 os_resize_anonymous_file(int fd, off_t size)
 {
 #ifdef HAVE_POSIX_FALLOCATE
-	/* 
-	 * Filesystems that do support fallocate will return EINVAL or
+	sigset_t mask;
+	sigset_t old_mask;
+
+	/*
+	 * posix_fallocate() might be interrupted, so we need to check
+	 * for EINTR and retry in that case.
+	 * However, in the presence of an alarm, the interrupt may trigger
+	 * repeatedly and prevent a large posix_fallocate() to ever complete
+	 * successfully, so we need to first block SIGALRM to prevent
+	 * this.
+	 */
+	sigemptyset(&mask);
+	sigaddset(&mask, SIGALRM);
+	sigprocmask(SIG_BLOCK, &mask, &old_mask);
+	/*
+	 * Filesystems that do not support fallocate will return EINVAL or
 	 * EOPNOTSUPP. In this case we need to fall back to ftruncate
 	 */
-	errno = posix_fallocate(fd, 0, size);
+	do {
+		errno = posix_fallocate(fd, 0, size);
+	} while (errno == EINTR);
+	sigprocmask(SIG_SETMASK, &old_mask, NULL);
 	if (errno == 0)
 		return 0;
 	else if (errno != EINVAL && errno != EOPNOTSUPP)