libreboot-utils: much stricter open() handling

abort on error, and do EINTR looping

Signed-off-by: Leah Rowe <leah@libreboot.org>

util/libreboot-utils/include/common.h

@@ -545,6 +545,7 @@ int fs_rename_at(int olddirfd, const char *old,
              int newdirfd, const char *new);
 int fs_open(const char *path, int flags);
 void free_and_set_null(char **buf);
+void open_on_eintr(char *path, int *fd, int flags, mode_t mode);
 struct filesystem *rootfs(void);
 int fs_resolve_at(int dirfd, const char *path, int flags);
 int fs_next_component(const char **p,

util/libreboot-utils/lib/file.c

@@ -589,6 +589,36 @@ free_and_set_null(char **buf)
 	*buf = NULL;
 }
 
+void
+open_on_eintr(char *path,
+    int *fd, int flags, mode_t mode)
+{
+	int r = -1;
+	int saved_errno = errno;
+
+	if (path == NULL)
+		err_exit(EINVAL, "open_on_eintr: null path");
+
+	if (fd == NULL)
+		err_exit(EFAULT, "%s: open_on_eintr: null fd ptr", path);
+
+	if (*fd >= 0)
+		err_exit(EBADF, "%s: open_on_eintr: file already open", path);
+
+	do {
+		r = open(path, flags, mode);
+	} while (r == -1 && (
+	    errno == EINTR || errno == EAGAIN ||
+	    errno == EWOULDBLOCK || errno == ETXTBSY));
+
+	if (r < 0)
+		err_exit(errno, "%s: open_on_eintr: could not close", path);
+
+	*fd = r;
+
+	errno = saved_errno;
+}
+
 void
 close_on_eintr(int *fd)
 {
@@ -672,8 +702,10 @@ rootfs(void)
 
 	if (!fs_initialised) {
 
-		global_fs.rootfd =
+		global_fs.rootfd = -1;
-		    open("/", O_RDONLY | O_DIRECTORY | O_CLOEXEC);
+
+		open_on_eintr("/", &global_fs.rootfd,
+		    O_RDONLY | O_DIRECTORY | O_CLOEXEC, 0400);
 
 		if (global_fs.rootfd < 0)
 			return NULL;

util/libreboot-utils/lib/rand.c

@@ -142,9 +142,7 @@ rset(void *buf, size_t n)
 #if defined(USE_URANDOM) && \
     ((USE_URANDOM) > 0)
 	int fd = -1;
-
+	open_on_eintr("/dev/urandom", &fd, O_RDONLY, 0400);
-	if ((fd = open("/dev/urandom", O_RDONLY)) < 0)
-		goto err;
 retry_rand:
 	if ((rc = read(fd, (unsigned char *)buf + off, n - off)) < 0) {
 #elif defined(__linux__)