util/nvmutil: use new fs_open functions for gbe

this unifies nvmutil's file handling with the
handling used by mkhtemp. a special function
has been written for this. this allows greater
flexibility since we can more easily check the
integrity of a file at inode/dev level; this
complements nvmutil's existing content-based
verification.

(this also fixes nvmutil, so that gbe files can
be changed again. mkhtemp broke it while i was
writing it, but now everything works again)

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

1 files changed, 52 insertions, 0 deletions

diff --git a/util/libreboot-utils/lib/mkhtemp.c b/util/libreboot-utils/lib/mkhtemp.c
index b30f6587..d1ebea25 100644
--- a/util/libreboot-utils/lib/mkhtemp.c
+++ b/util/libreboot-utils/lib/mkhtemp.c
@@ -39,6 +39,58 @@ new_tmpdir(int *fd, char **path)
 	return new_tmp_common(fd, path, MKHTEMP_DIR);
 }
 
+/* not used by mkhtemp util, but by nvmutil.
+ * it leaves an st variable set after return,
+ * so that verification can be done on a file
+ * being used, before writing it elsewhere
+ */
+int
+new_tmpfile_at(int dirfd, struct stat *st_dir,
+    int *fd, char **name)
+{
+	struct stat st;
+	char suffix[] = "tmp.XXXXXXXXXX";
+	size_t len;
+	char *buf = NULL;
+	char *fname;
+	int saved_errno = errno;
+
+#if defined(PATH_LEN) && \
+    (PATH_LEN) >= 256
+	size_t maxlen = PATH_LEN;
+#else
+	size_t maxlen = 4096;
+#endif
+
+	if (if_err(fd == NULL || name == NULL || st_dir == NULL, EFAULT) ||
+	    if_err(*fd >= 0, EEXIST) ||
+	    if_err(dirfd < 0, EBADF) ||
+	    if_err_sys(slen(suffix, maxlen, &len) < 0) ||
+	    if_err_sys((malloc(len + 1)) == NULL))
+		return -1;
+
+	memcpy(buf, suffix, len + 1);
+	fname = buf;
+
+	*fd = mkhtemp(fd, &st,
+	    buf, dirfd, fname,
+	    st_dir, MKHTEMP_FILE);
+
+	if (*fd < 0)
+		goto err;
+
+	*name = buf;
+	errno = saved_errno;
+
+	return 0;
+
+err:
+	free_if_null(&buf);
+	close_no_err(fd);
+
+	return -1;
+}
+
 /* WARNING:
  * on error, *path (at **path) may be
    NULL, or if the error pertains to